1 /* Functions related to building classes and their related objects.
2 Copyright (C) 1987-2019 Free Software Foundation, Inc.
3 Contributed by Michael Tiemann (tiemann@cygnus.com)
4
5 This file is part of GCC.
6
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
10 any later version.
11
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
20
21
22 /* High-level class interface. */
23
24 #include "config.h"
25 #include "system.h"
26 #include "coretypes.h"
27 #include "target.h"
28 #include "cp-tree.h"
29 #include "stringpool.h"
30 #include "cgraph.h"
31 #include "stor-layout.h"
32 #include "attribs.h"
33 #include "flags.h"
34 #include "toplev.h"
35 #include "convert.h"
36 #include "dumpfile.h"
37 #include "gimplify.h"
38 #include "intl.h"
39 #include "asan.h"
40
41 /* Id for dumping the class hierarchy. */
42 int class_dump_id;
43
44 /* The number of nested classes being processed. If we are not in the
45 scope of any class, this is zero. */
46
47 int current_class_depth;
48
49 /* In order to deal with nested classes, we keep a stack of classes.
50 The topmost entry is the innermost class, and is the entry at index
51 CURRENT_CLASS_DEPTH */
52
53 typedef struct class_stack_node {
54 /* The name of the class. */
55 tree name;
56
57 /* The _TYPE node for the class. */
58 tree type;
59
60 /* The access specifier pending for new declarations in the scope of
61 this class. */
62 tree access;
63
64 /* If were defining TYPE, the names used in this class. */
65 splay_tree names_used;
66
67 /* Nonzero if this class is no longer open, because of a call to
68 push_to_top_level. */
69 size_t hidden;
70 }* class_stack_node_t;
71
72 struct vtbl_init_data
73 {
74 /* The base for which we're building initializers. */
75 tree binfo;
76 /* The type of the most-derived type. */
77 tree derived;
78 /* The binfo for the dynamic type. This will be TYPE_BINFO (derived),
79 unless ctor_vtbl_p is true. */
80 tree rtti_binfo;
81 /* The negative-index vtable initializers built up so far. These
82 are in order from least negative index to most negative index. */
83 vec<constructor_elt, va_gc> *inits;
84 /* The binfo for the virtual base for which we're building
85 vcall offset initializers. */
86 tree vbase;
87 /* The functions in vbase for which we have already provided vcall
88 offsets. */
89 vec<tree, va_gc> *fns;
90 /* The vtable index of the next vcall or vbase offset. */
91 tree index;
92 /* Nonzero if we are building the initializer for the primary
93 vtable. */
94 int primary_vtbl_p;
95 /* Nonzero if we are building the initializer for a construction
96 vtable. */
97 int ctor_vtbl_p;
98 /* True when adding vcall offset entries to the vtable. False when
99 merely computing the indices. */
100 bool generate_vcall_entries;
101 };
102
103 /* The type of a function passed to walk_subobject_offsets. */
104 typedef int (*subobject_offset_fn) (tree, tree, splay_tree);
105
106 /* The stack itself. This is a dynamically resized array. The
107 number of elements allocated is CURRENT_CLASS_STACK_SIZE. */
108 static int current_class_stack_size;
109 static class_stack_node_t current_class_stack;
110
111 /* The size of the largest empty class seen in this translation unit. */
112 static GTY (()) tree sizeof_biggest_empty_class;
113
114 static tree get_vfield_name (tree);
115 static void finish_struct_anon (tree);
116 static tree get_vtable_name (tree);
117 static void get_basefndecls (tree, tree, vec<tree> *);
118 static int build_primary_vtable (tree, tree);
119 static int build_secondary_vtable (tree);
120 static void finish_vtbls (tree);
121 static void modify_vtable_entry (tree, tree, tree, tree, tree *);
122 static void finish_struct_bits (tree);
123 static int alter_access (tree, tree, tree);
124 static void handle_using_decl (tree, tree);
125 static tree dfs_modify_vtables (tree, void *);
126 static tree modify_all_vtables (tree, tree);
127 static void determine_primary_bases (tree);
128 static void maybe_warn_about_overly_private_class (tree);
129 static void add_implicitly_declared_members (tree, tree*, int, int);
130 static tree fixed_type_or_null (tree, int *, int *);
131 static tree build_simple_base_path (tree expr, tree binfo);
132 static void build_vtbl_initializer (tree, tree, tree, tree, int *,
133 vec<constructor_elt, va_gc> **);
134 static bool check_bitfield_decl (tree);
135 static bool check_field_decl (tree, tree, int *, int *);
136 static void check_field_decls (tree, tree *, int *, int *);
137 static tree *build_base_field (record_layout_info, tree, splay_tree, tree *);
138 static void build_base_fields (record_layout_info, splay_tree, tree *);
139 static void check_methods (tree);
140 static void remove_zero_width_bit_fields (tree);
141 static bool accessible_nvdtor_p (tree);
142
143 /* Used by find_flexarrays and related functions. */
144 struct flexmems_t;
145 static void diagnose_flexarrays (tree, const flexmems_t *);
146 static void find_flexarrays (tree, flexmems_t *, bool = false,
147 tree = NULL_TREE, tree = NULL_TREE);
148 static void check_flexarrays (tree, flexmems_t * = NULL, bool = false);
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 propagate_binfo_offsets (tree, tree);
155 static void layout_virtual_bases (record_layout_info, splay_tree);
156 static void build_vbase_offset_vtbl_entries (tree, vtbl_init_data *);
157 static void add_vcall_offset_vtbl_entries_r (tree, vtbl_init_data *);
158 static void add_vcall_offset_vtbl_entries_1 (tree, vtbl_init_data *);
159 static void build_vcall_offset_vtbl_entries (tree, vtbl_init_data *);
160 static void add_vcall_offset (tree, tree, vtbl_init_data *);
161 static void layout_vtable_decl (tree, int);
162 static tree dfs_find_final_overrider_pre (tree, void *);
163 static tree dfs_find_final_overrider_post (tree, void *);
164 static tree find_final_overrider (tree, tree, tree);
165 static int make_new_vtable (tree, tree);
166 static tree get_primary_binfo (tree);
167 static int maybe_indent_hierarchy (FILE *, int, int);
168 static tree dump_class_hierarchy_r (FILE *, dump_flags_t, tree, tree, int);
169 static void dump_class_hierarchy (tree);
170 static void dump_class_hierarchy_1 (FILE *, dump_flags_t, tree);
171 static void dump_array (FILE *, tree);
172 static void dump_vtable (tree, tree, tree);
173 static void dump_vtt (tree, tree);
174 static void dump_thunk (FILE *, int, tree);
175 static tree build_vtable (tree, tree, tree);
176 static void initialize_vtable (tree, vec<constructor_elt, va_gc> *);
177 static void layout_nonempty_base_or_field (record_layout_info,
178 tree, tree, splay_tree);
179 static void accumulate_vtbl_inits (tree, tree, tree, tree, tree,
180 vec<constructor_elt, va_gc> **);
181 static void dfs_accumulate_vtbl_inits (tree, tree, tree, tree, tree,
182 vec<constructor_elt, va_gc> **);
183 static void build_rtti_vtbl_entries (tree, vtbl_init_data *);
184 static void build_vcall_and_vbase_vtbl_entries (tree, vtbl_init_data *);
185 static void clone_constructors_and_destructors (tree);
186 static tree build_clone (tree, tree);
187 static void update_vtable_entry_for_fn (tree, tree, tree, tree *, unsigned);
188 static void build_ctor_vtbl_group (tree, tree);
189 static void build_vtt (tree);
190 static tree binfo_ctor_vtable (tree);
191 static void build_vtt_inits (tree, tree, vec<constructor_elt, va_gc> **,
192 tree *);
193 static tree dfs_build_secondary_vptr_vtt_inits (tree, void *);
194 static tree dfs_fixup_binfo_vtbls (tree, void *);
195 static int record_subobject_offset (tree, tree, splay_tree);
196 static int check_subobject_offset (tree, tree, splay_tree);
197 static int walk_subobject_offsets (tree, subobject_offset_fn,
198 tree, splay_tree, tree, int);
199 static int layout_conflict_p (tree, tree, splay_tree, int);
200 static int splay_tree_compare_integer_csts (splay_tree_key k1,
201 splay_tree_key k2);
202 static void warn_about_ambiguous_bases (tree);
203 static bool type_requires_array_cookie (tree);
204 static bool base_derived_from (tree, tree);
205 static int empty_base_at_nonzero_offset_p (tree, tree, splay_tree);
206 static tree end_of_base (tree);
207 static tree get_vcall_index (tree, tree);
208 static bool type_maybe_constexpr_default_constructor (tree);
209 static bool field_poverlapping_p (tree);
210
211 /* Return a COND_EXPR that executes TRUE_STMT if this execution of the
212 'structor is in charge of 'structing virtual bases, or FALSE_STMT
213 otherwise. */
214
215 tree
build_if_in_charge(tree true_stmt,tree false_stmt)216 build_if_in_charge (tree true_stmt, tree false_stmt)
217 {
218 gcc_assert (DECL_HAS_IN_CHARGE_PARM_P (current_function_decl));
219 tree cmp = build2 (NE_EXPR, boolean_type_node,
220 current_in_charge_parm, integer_zero_node);
221 tree type = unlowered_expr_type (true_stmt);
222 if (VOID_TYPE_P (type))
223 type = unlowered_expr_type (false_stmt);
224 tree cond = build3 (COND_EXPR, type,
225 cmp, true_stmt, false_stmt);
226 return cond;
227 }
228
229 /* Convert to or from a base subobject. EXPR is an expression of type
230 `A' or `A*', an expression of type `B' or `B*' is returned. To
231 convert A to a base B, CODE is PLUS_EXPR and BINFO is the binfo for
232 the B base instance within A. To convert base A to derived B, CODE
233 is MINUS_EXPR and BINFO is the binfo for the A instance within B.
234 In this latter case, A must not be a morally virtual base of B.
235 NONNULL is true if EXPR is known to be non-NULL (this is only
236 needed when EXPR is of pointer type). CV qualifiers are preserved
237 from EXPR. */
238
239 tree
build_base_path(enum tree_code code,tree expr,tree binfo,int nonnull,tsubst_flags_t complain)240 build_base_path (enum tree_code code,
241 tree expr,
242 tree binfo,
243 int nonnull,
244 tsubst_flags_t complain)
245 {
246 tree v_binfo = NULL_TREE;
247 tree d_binfo = NULL_TREE;
248 tree probe;
249 tree offset;
250 tree target_type;
251 tree null_test = NULL;
252 tree ptr_target_type;
253 int fixed_type_p;
254 int want_pointer = TYPE_PTR_P (TREE_TYPE (expr));
255 bool has_empty = false;
256 bool virtual_access;
257 bool rvalue = false;
258
259 if (expr == error_mark_node || binfo == error_mark_node || !binfo)
260 return error_mark_node;
261
262 for (probe = binfo; probe; probe = BINFO_INHERITANCE_CHAIN (probe))
263 {
264 d_binfo = probe;
265 if (is_empty_class (BINFO_TYPE (probe)))
266 has_empty = true;
267 if (!v_binfo && BINFO_VIRTUAL_P (probe))
268 v_binfo = probe;
269 }
270
271 probe = TYPE_MAIN_VARIANT (TREE_TYPE (expr));
272 if (want_pointer)
273 probe = TYPE_MAIN_VARIANT (TREE_TYPE (probe));
274 if (dependent_type_p (probe))
275 if (tree open = currently_open_class (probe))
276 probe = open;
277
278 if (code == PLUS_EXPR
279 && !SAME_BINFO_TYPE_P (BINFO_TYPE (d_binfo), probe))
280 {
281 /* This can happen when adjust_result_of_qualified_name_lookup can't
282 find a unique base binfo in a call to a member function. We
283 couldn't give the diagnostic then since we might have been calling
284 a static member function, so we do it now. In other cases, eg.
285 during error recovery (c++/71979), we may not have a base at all. */
286 if (complain & tf_error)
287 {
288 tree base = lookup_base (probe, BINFO_TYPE (d_binfo),
289 ba_unique, NULL, complain);
290 gcc_assert (base == error_mark_node || !base);
291 }
292 return error_mark_node;
293 }
294
295 gcc_assert ((code == MINUS_EXPR
296 && SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), probe))
297 || code == PLUS_EXPR);
298
299 if (binfo == d_binfo)
300 /* Nothing to do. */
301 return expr;
302
303 if (code == MINUS_EXPR && v_binfo)
304 {
305 if (complain & tf_error)
306 {
307 if (SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), BINFO_TYPE (v_binfo)))
308 {
309 if (want_pointer)
310 error ("cannot convert from pointer to base class %qT to "
311 "pointer to derived class %qT because the base is "
312 "virtual", BINFO_TYPE (binfo), BINFO_TYPE (d_binfo));
313 else
314 error ("cannot convert from base class %qT to derived "
315 "class %qT because the base is virtual",
316 BINFO_TYPE (binfo), BINFO_TYPE (d_binfo));
317 }
318 else
319 {
320 if (want_pointer)
321 error ("cannot convert from pointer to base class %qT to "
322 "pointer to derived class %qT via virtual base %qT",
323 BINFO_TYPE (binfo), BINFO_TYPE (d_binfo),
324 BINFO_TYPE (v_binfo));
325 else
326 error ("cannot convert from base class %qT to derived "
327 "class %qT via virtual base %qT", BINFO_TYPE (binfo),
328 BINFO_TYPE (d_binfo), BINFO_TYPE (v_binfo));
329 }
330 }
331 return error_mark_node;
332 }
333
334 if (!want_pointer)
335 {
336 rvalue = !lvalue_p (expr);
337 /* This must happen before the call to save_expr. */
338 expr = cp_build_addr_expr (expr, complain);
339 }
340 else
341 expr = mark_rvalue_use (expr);
342
343 offset = BINFO_OFFSET (binfo);
344 fixed_type_p = resolves_to_fixed_type_p (expr, &nonnull);
345 target_type = code == PLUS_EXPR ? BINFO_TYPE (binfo) : BINFO_TYPE (d_binfo);
346 /* TARGET_TYPE has been extracted from BINFO, and, is therefore always
347 cv-unqualified. Extract the cv-qualifiers from EXPR so that the
348 expression returned matches the input. */
349 target_type = cp_build_qualified_type
350 (target_type, cp_type_quals (TREE_TYPE (TREE_TYPE (expr))));
351 ptr_target_type = build_pointer_type (target_type);
352
353 /* Do we need to look in the vtable for the real offset? */
354 virtual_access = (v_binfo && fixed_type_p <= 0);
355
356 /* Don't bother with the calculations inside sizeof; they'll ICE if the
357 source type is incomplete and the pointer value doesn't matter. In a
358 template (even in instantiate_non_dependent_expr), we don't have vtables
359 set up properly yet, and the value doesn't matter there either; we're
360 just interested in the result of overload resolution. */
361 if (cp_unevaluated_operand != 0
362 || processing_template_decl
363 || in_template_function ())
364 {
365 expr = build_nop (ptr_target_type, expr);
366 goto indout;
367 }
368
369 if (!COMPLETE_TYPE_P (probe))
370 {
371 if (complain & tf_error)
372 error ("cannot convert from %qT to base class %qT because %qT is "
373 "incomplete", BINFO_TYPE (d_binfo), BINFO_TYPE (binfo),
374 BINFO_TYPE (d_binfo));
375 return error_mark_node;
376 }
377
378 /* If we're in an NSDMI, we don't have the full constructor context yet
379 that we need for converting to a virtual base, so just build a stub
380 CONVERT_EXPR and expand it later in bot_replace. */
381 if (virtual_access && fixed_type_p < 0
382 && current_scope () != current_function_decl)
383 {
384 expr = build1 (CONVERT_EXPR, ptr_target_type, expr);
385 CONVERT_EXPR_VBASE_PATH (expr) = true;
386 goto indout;
387 }
388
389 /* Do we need to check for a null pointer? */
390 if (want_pointer && !nonnull)
391 {
392 /* If we know the conversion will not actually change the value
393 of EXPR, then we can avoid testing the expression for NULL.
394 We have to avoid generating a COMPONENT_REF for a base class
395 field, because other parts of the compiler know that such
396 expressions are always non-NULL. */
397 if (!virtual_access && integer_zerop (offset))
398 return build_nop (ptr_target_type, expr);
399 null_test = error_mark_node;
400 }
401
402 /* Protect against multiple evaluation if necessary. */
403 if (TREE_SIDE_EFFECTS (expr) && (null_test || virtual_access))
404 expr = save_expr (expr);
405
406 /* Now that we've saved expr, build the real null test. */
407 if (null_test)
408 {
409 tree zero = cp_convert (TREE_TYPE (expr), nullptr_node, complain);
410 null_test = build2_loc (input_location, NE_EXPR, boolean_type_node,
411 expr, zero);
412 /* This is a compiler generated comparison, don't emit
413 e.g. -Wnonnull-compare warning for it. */
414 TREE_NO_WARNING (null_test) = 1;
415 }
416
417 /* If this is a simple base reference, express it as a COMPONENT_REF. */
418 if (code == PLUS_EXPR && !virtual_access
419 /* We don't build base fields for empty bases, and they aren't very
420 interesting to the optimizers anyway. */
421 && !has_empty)
422 {
423 expr = cp_build_fold_indirect_ref (expr);
424 expr = build_simple_base_path (expr, binfo);
425 if (rvalue && lvalue_p (expr))
426 expr = move (expr);
427 if (want_pointer)
428 expr = build_address (expr);
429 target_type = TREE_TYPE (expr);
430 goto out;
431 }
432
433 if (virtual_access)
434 {
435 /* Going via virtual base V_BINFO. We need the static offset
436 from V_BINFO to BINFO, and the dynamic offset from D_BINFO to
437 V_BINFO. That offset is an entry in D_BINFO's vtable. */
438 tree v_offset;
439
440 if (fixed_type_p < 0 && in_base_initializer)
441 {
442 /* In a base member initializer, we cannot rely on the
443 vtable being set up. We have to indirect via the
444 vtt_parm. */
445 tree t;
446
447 t = TREE_TYPE (TYPE_VFIELD (current_class_type));
448 t = build_pointer_type (t);
449 v_offset = fold_convert (t, current_vtt_parm);
450 v_offset = cp_build_fold_indirect_ref (v_offset);
451 }
452 else
453 {
454 tree t = expr;
455 if (sanitize_flags_p (SANITIZE_VPTR)
456 && fixed_type_p == 0)
457 {
458 t = cp_ubsan_maybe_instrument_cast_to_vbase (input_location,
459 probe, expr);
460 if (t == NULL_TREE)
461 t = expr;
462 }
463 v_offset = build_vfield_ref (cp_build_fold_indirect_ref (t),
464 TREE_TYPE (TREE_TYPE (expr)));
465 }
466
467 if (v_offset == error_mark_node)
468 return error_mark_node;
469
470 v_offset = fold_build_pointer_plus (v_offset, BINFO_VPTR_FIELD (v_binfo));
471 v_offset = build1 (NOP_EXPR,
472 build_pointer_type (ptrdiff_type_node),
473 v_offset);
474 v_offset = cp_build_fold_indirect_ref (v_offset);
475 TREE_CONSTANT (v_offset) = 1;
476
477 offset = convert_to_integer (ptrdiff_type_node,
478 size_diffop_loc (input_location, offset,
479 BINFO_OFFSET (v_binfo)));
480
481 if (!integer_zerop (offset))
482 v_offset = build2 (code, ptrdiff_type_node, v_offset, offset);
483
484 if (fixed_type_p < 0)
485 /* Negative fixed_type_p means this is a constructor or destructor;
486 virtual base layout is fixed in in-charge [cd]tors, but not in
487 base [cd]tors. */
488 offset = build_if_in_charge
489 (convert_to_integer (ptrdiff_type_node, BINFO_OFFSET (binfo)),
490 v_offset);
491 else
492 offset = v_offset;
493 }
494
495 if (want_pointer)
496 target_type = ptr_target_type;
497
498 expr = build1 (NOP_EXPR, ptr_target_type, expr);
499
500 if (!integer_zerop (offset))
501 {
502 offset = fold_convert (sizetype, offset);
503 if (code == MINUS_EXPR)
504 offset = fold_build1_loc (input_location, NEGATE_EXPR, sizetype, offset);
505 expr = fold_build_pointer_plus (expr, offset);
506 }
507 else
508 null_test = NULL;
509
510 indout:
511 if (!want_pointer)
512 {
513 expr = cp_build_fold_indirect_ref (expr);
514 if (rvalue)
515 expr = move (expr);
516 }
517
518 out:
519 if (null_test)
520 expr = fold_build3_loc (input_location, COND_EXPR, target_type, null_test, expr,
521 build_zero_cst (target_type));
522
523 return expr;
524 }
525
526 /* Subroutine of build_base_path; EXPR and BINFO are as in that function.
527 Perform a derived-to-base conversion by recursively building up a
528 sequence of COMPONENT_REFs to the appropriate base fields. */
529
530 static tree
build_simple_base_path(tree expr,tree binfo)531 build_simple_base_path (tree expr, tree binfo)
532 {
533 tree type = BINFO_TYPE (binfo);
534 tree d_binfo = BINFO_INHERITANCE_CHAIN (binfo);
535 tree field;
536
537 if (d_binfo == NULL_TREE)
538 {
539 tree temp;
540
541 gcc_assert (TYPE_MAIN_VARIANT (TREE_TYPE (expr)) == type);
542
543 /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x'
544 into `(*(a ? &b : &c)).x', and so on. A COND_EXPR is only
545 an lvalue in the front end; only _DECLs and _REFs are lvalues
546 in the back end. */
547 temp = unary_complex_lvalue (ADDR_EXPR, expr);
548 if (temp)
549 expr = cp_build_fold_indirect_ref (temp);
550
551 return expr;
552 }
553
554 /* Recurse. */
555 expr = build_simple_base_path (expr, d_binfo);
556
557 for (field = TYPE_FIELDS (BINFO_TYPE (d_binfo));
558 field; field = DECL_CHAIN (field))
559 /* Is this the base field created by build_base_field? */
560 if (TREE_CODE (field) == FIELD_DECL
561 && DECL_FIELD_IS_BASE (field)
562 && TREE_TYPE (field) == type
563 /* If we're looking for a field in the most-derived class,
564 also check the field offset; we can have two base fields
565 of the same type if one is an indirect virtual base and one
566 is a direct non-virtual base. */
567 && (BINFO_INHERITANCE_CHAIN (d_binfo)
568 || tree_int_cst_equal (byte_position (field),
569 BINFO_OFFSET (binfo))))
570 {
571 /* We don't use build_class_member_access_expr here, as that
572 has unnecessary checks, and more importantly results in
573 recursive calls to dfs_walk_once. */
574 int type_quals = cp_type_quals (TREE_TYPE (expr));
575
576 expr = build3 (COMPONENT_REF,
577 cp_build_qualified_type (type, type_quals),
578 expr, field, NULL_TREE);
579 /* Mark the expression const or volatile, as appropriate.
580 Even though we've dealt with the type above, we still have
581 to mark the expression itself. */
582 if (type_quals & TYPE_QUAL_CONST)
583 TREE_READONLY (expr) = 1;
584 if (type_quals & TYPE_QUAL_VOLATILE)
585 TREE_THIS_VOLATILE (expr) = 1;
586
587 return expr;
588 }
589
590 /* Didn't find the base field?!? */
591 gcc_unreachable ();
592 }
593
594 /* Convert OBJECT to the base TYPE. OBJECT is an expression whose
595 type is a class type or a pointer to a class type. In the former
596 case, TYPE is also a class type; in the latter it is another
597 pointer type. If CHECK_ACCESS is true, an error message is emitted
598 if TYPE is inaccessible. If OBJECT has pointer type, the value is
599 assumed to be non-NULL. */
600
601 tree
convert_to_base(tree object,tree type,bool check_access,bool nonnull,tsubst_flags_t complain)602 convert_to_base (tree object, tree type, bool check_access, bool nonnull,
603 tsubst_flags_t complain)
604 {
605 tree binfo;
606 tree object_type;
607
608 if (TYPE_PTR_P (TREE_TYPE (object)))
609 {
610 object_type = TREE_TYPE (TREE_TYPE (object));
611 type = TREE_TYPE (type);
612 }
613 else
614 object_type = TREE_TYPE (object);
615
616 binfo = lookup_base (object_type, type, check_access ? ba_check : ba_unique,
617 NULL, complain);
618 if (!binfo || binfo == error_mark_node)
619 return error_mark_node;
620
621 return build_base_path (PLUS_EXPR, object, binfo, nonnull, complain);
622 }
623
624 /* EXPR is an expression with unqualified class type. BASE is a base
625 binfo of that class type. Returns EXPR, converted to the BASE
626 type. This function assumes that EXPR is the most derived class;
627 therefore virtual bases can be found at their static offsets. */
628
629 tree
convert_to_base_statically(tree expr,tree base)630 convert_to_base_statically (tree expr, tree base)
631 {
632 tree expr_type;
633
634 expr_type = TREE_TYPE (expr);
635 if (!SAME_BINFO_TYPE_P (BINFO_TYPE (base), expr_type))
636 {
637 /* If this is a non-empty base, use a COMPONENT_REF. */
638 if (!is_empty_class (BINFO_TYPE (base)))
639 return build_simple_base_path (expr, base);
640
641 /* We use fold_build2 and fold_convert below to simplify the trees
642 provided to the optimizers. It is not safe to call these functions
643 when processing a template because they do not handle C++-specific
644 trees. */
645 gcc_assert (!processing_template_decl);
646 expr = cp_build_addr_expr (expr, tf_warning_or_error);
647 if (!integer_zerop (BINFO_OFFSET (base)))
648 expr = fold_build_pointer_plus_loc (input_location,
649 expr, BINFO_OFFSET (base));
650 expr = fold_convert (build_pointer_type (BINFO_TYPE (base)), expr);
651 expr = build_fold_indirect_ref_loc (input_location, expr);
652 }
653
654 return expr;
655 }
656
657
658 tree
build_vfield_ref(tree datum,tree type)659 build_vfield_ref (tree datum, tree type)
660 {
661 tree vfield, vcontext;
662
663 if (datum == error_mark_node
664 /* Can happen in case of duplicate base types (c++/59082). */
665 || !TYPE_VFIELD (type))
666 return error_mark_node;
667
668 /* First, convert to the requested type. */
669 if (!same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (datum), type))
670 datum = convert_to_base (datum, type, /*check_access=*/false,
671 /*nonnull=*/true, tf_warning_or_error);
672
673 /* Second, the requested type may not be the owner of its own vptr.
674 If not, convert to the base class that owns it. We cannot use
675 convert_to_base here, because VCONTEXT may appear more than once
676 in the inheritance hierarchy of TYPE, and thus direct conversion
677 between the types may be ambiguous. Following the path back up
678 one step at a time via primary bases avoids the problem. */
679 vfield = TYPE_VFIELD (type);
680 vcontext = DECL_CONTEXT (vfield);
681 while (!same_type_ignoring_top_level_qualifiers_p (vcontext, type))
682 {
683 datum = build_simple_base_path (datum, CLASSTYPE_PRIMARY_BINFO (type));
684 type = TREE_TYPE (datum);
685 }
686
687 return build3 (COMPONENT_REF, TREE_TYPE (vfield), datum, vfield, NULL_TREE);
688 }
689
690 /* Given an object INSTANCE, return an expression which yields the
691 vtable element corresponding to INDEX. There are many special
692 cases for INSTANCE which we take care of here, mainly to avoid
693 creating extra tree nodes when we don't have to. */
694
695 tree
build_vtbl_ref(tree instance,tree idx)696 build_vtbl_ref (tree instance, tree idx)
697 {
698 tree aref;
699 tree vtbl = NULL_TREE;
700
701 /* Try to figure out what a reference refers to, and
702 access its virtual function table directly. */
703
704 int cdtorp = 0;
705 tree fixed_type = fixed_type_or_null (instance, NULL, &cdtorp);
706
707 tree basetype = non_reference (TREE_TYPE (instance));
708
709 if (fixed_type && !cdtorp)
710 {
711 tree binfo = lookup_base (fixed_type, basetype,
712 ba_unique, NULL, tf_none);
713 if (binfo && binfo != error_mark_node)
714 vtbl = unshare_expr (BINFO_VTABLE (binfo));
715 }
716
717 if (!vtbl)
718 vtbl = build_vfield_ref (instance, basetype);
719
720 aref = build_array_ref (input_location, vtbl, idx);
721 TREE_CONSTANT (aref) |= TREE_CONSTANT (vtbl) && TREE_CONSTANT (idx);
722
723 return aref;
724 }
725
726 /* Given a stable object pointer INSTANCE_PTR, return an expression which
727 yields a function pointer corresponding to vtable element INDEX. */
728
729 tree
build_vfn_ref(tree instance_ptr,tree idx)730 build_vfn_ref (tree instance_ptr, tree idx)
731 {
732 tree aref;
733
734 aref = build_vtbl_ref (cp_build_fold_indirect_ref (instance_ptr), idx);
735
736 /* When using function descriptors, the address of the
737 vtable entry is treated as a function pointer. */
738 if (TARGET_VTABLE_USES_DESCRIPTORS)
739 aref = build1 (NOP_EXPR, TREE_TYPE (aref),
740 cp_build_addr_expr (aref, tf_warning_or_error));
741
742 /* Remember this as a method reference, for later devirtualization. */
743 aref = build3 (OBJ_TYPE_REF, TREE_TYPE (aref), aref, instance_ptr, idx);
744
745 return aref;
746 }
747
748 /* Return the name of the virtual function table (as an IDENTIFIER_NODE)
749 for the given TYPE. */
750
751 static tree
get_vtable_name(tree type)752 get_vtable_name (tree type)
753 {
754 return mangle_vtbl_for_type (type);
755 }
756
757 /* DECL is an entity associated with TYPE, like a virtual table or an
758 implicitly generated constructor. Determine whether or not DECL
759 should have external or internal linkage at the object file
760 level. This routine does not deal with COMDAT linkage and other
761 similar complexities; it simply sets TREE_PUBLIC if it possible for
762 entities in other translation units to contain copies of DECL, in
763 the abstract. */
764
765 void
set_linkage_according_to_type(tree,tree decl)766 set_linkage_according_to_type (tree /*type*/, tree decl)
767 {
768 TREE_PUBLIC (decl) = 1;
769 determine_visibility (decl);
770 }
771
772 /* Create a VAR_DECL for a primary or secondary vtable for CLASS_TYPE.
773 (For a secondary vtable for B-in-D, CLASS_TYPE should be D, not B.)
774 Use NAME for the name of the vtable, and VTABLE_TYPE for its type. */
775
776 static tree
build_vtable(tree class_type,tree name,tree vtable_type)777 build_vtable (tree class_type, tree name, tree vtable_type)
778 {
779 tree decl;
780
781 decl = build_lang_decl (VAR_DECL, name, vtable_type);
782 /* vtable names are already mangled; give them their DECL_ASSEMBLER_NAME
783 now to avoid confusion in mangle_decl. */
784 SET_DECL_ASSEMBLER_NAME (decl, name);
785 DECL_CONTEXT (decl) = class_type;
786 DECL_ARTIFICIAL (decl) = 1;
787 TREE_STATIC (decl) = 1;
788 TREE_READONLY (decl) = 1;
789 DECL_VIRTUAL_P (decl) = 1;
790 SET_DECL_ALIGN (decl, TARGET_VTABLE_ENTRY_ALIGN);
791 DECL_USER_ALIGN (decl) = true;
792 DECL_VTABLE_OR_VTT_P (decl) = 1;
793 set_linkage_according_to_type (class_type, decl);
794 /* The vtable has not been defined -- yet. */
795 DECL_EXTERNAL (decl) = 1;
796 DECL_NOT_REALLY_EXTERN (decl) = 1;
797
798 /* Mark the VAR_DECL node representing the vtable itself as a
799 "gratuitous" one, thereby forcing dwarfout.c to ignore it. It
800 is rather important that such things be ignored because any
801 effort to actually generate DWARF for them will run into
802 trouble when/if we encounter code like:
803
804 #pragma interface
805 struct S { virtual void member (); };
806
807 because the artificial declaration of the vtable itself (as
808 manufactured by the g++ front end) will say that the vtable is
809 a static member of `S' but only *after* the debug output for
810 the definition of `S' has already been output. This causes
811 grief because the DWARF entry for the definition of the vtable
812 will try to refer back to an earlier *declaration* of the
813 vtable as a static member of `S' and there won't be one. We
814 might be able to arrange to have the "vtable static member"
815 attached to the member list for `S' before the debug info for
816 `S' get written (which would solve the problem) but that would
817 require more intrusive changes to the g++ front end. */
818 DECL_IGNORED_P (decl) = 1;
819
820 return decl;
821 }
822
823 /* Get the VAR_DECL of the vtable for TYPE. TYPE need not be polymorphic,
824 or even complete. If this does not exist, create it. If COMPLETE is
825 nonzero, then complete the definition of it -- that will render it
826 impossible to actually build the vtable, but is useful to get at those
827 which are known to exist in the runtime. */
828
829 tree
get_vtable_decl(tree type,int complete)830 get_vtable_decl (tree type, int complete)
831 {
832 tree decl;
833
834 if (CLASSTYPE_VTABLES (type))
835 return CLASSTYPE_VTABLES (type);
836
837 decl = build_vtable (type, get_vtable_name (type), vtbl_type_node);
838 CLASSTYPE_VTABLES (type) = decl;
839
840 if (complete)
841 {
842 DECL_EXTERNAL (decl) = 1;
843 cp_finish_decl (decl, NULL_TREE, false, NULL_TREE, 0);
844 }
845
846 return decl;
847 }
848
849 /* Build the primary virtual function table for TYPE. If BINFO is
850 non-NULL, build the vtable starting with the initial approximation
851 that it is the same as the one which is the head of the association
852 list. Returns a nonzero value if a new vtable is actually
853 created. */
854
855 static int
build_primary_vtable(tree binfo,tree type)856 build_primary_vtable (tree binfo, tree type)
857 {
858 tree decl;
859 tree virtuals;
860
861 decl = get_vtable_decl (type, /*complete=*/0);
862
863 if (binfo)
864 {
865 if (BINFO_NEW_VTABLE_MARKED (binfo))
866 /* We have already created a vtable for this base, so there's
867 no need to do it again. */
868 return 0;
869
870 virtuals = copy_list (BINFO_VIRTUALS (binfo));
871 TREE_TYPE (decl) = TREE_TYPE (get_vtbl_decl_for_binfo (binfo));
872 DECL_SIZE (decl) = TYPE_SIZE (TREE_TYPE (decl));
873 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (TREE_TYPE (decl));
874 }
875 else
876 {
877 gcc_assert (TREE_TYPE (decl) == vtbl_type_node);
878 virtuals = NULL_TREE;
879 }
880
881 /* Initialize the association list for this type, based
882 on our first approximation. */
883 BINFO_VTABLE (TYPE_BINFO (type)) = decl;
884 BINFO_VIRTUALS (TYPE_BINFO (type)) = virtuals;
885 SET_BINFO_NEW_VTABLE_MARKED (TYPE_BINFO (type));
886 return 1;
887 }
888
889 /* Give BINFO a new virtual function table which is initialized
890 with a skeleton-copy of its original initialization. The only
891 entry that changes is the `delta' entry, so we can really
892 share a lot of structure.
893
894 FOR_TYPE is the most derived type which caused this table to
895 be needed.
896
897 Returns nonzero if we haven't met BINFO before.
898
899 The order in which vtables are built (by calling this function) for
900 an object must remain the same, otherwise a binary incompatibility
901 can result. */
902
903 static int
build_secondary_vtable(tree binfo)904 build_secondary_vtable (tree binfo)
905 {
906 if (BINFO_NEW_VTABLE_MARKED (binfo))
907 /* We already created a vtable for this base. There's no need to
908 do it again. */
909 return 0;
910
911 /* Remember that we've created a vtable for this BINFO, so that we
912 don't try to do so again. */
913 SET_BINFO_NEW_VTABLE_MARKED (binfo);
914
915 /* Make fresh virtual list, so we can smash it later. */
916 BINFO_VIRTUALS (binfo) = copy_list (BINFO_VIRTUALS (binfo));
917
918 /* Secondary vtables are laid out as part of the same structure as
919 the primary vtable. */
920 BINFO_VTABLE (binfo) = NULL_TREE;
921 return 1;
922 }
923
924 /* Create a new vtable for BINFO which is the hierarchy dominated by
925 T. Return nonzero if we actually created a new vtable. */
926
927 static int
make_new_vtable(tree t,tree binfo)928 make_new_vtable (tree t, tree binfo)
929 {
930 if (binfo == TYPE_BINFO (t))
931 /* In this case, it is *type*'s vtable we are modifying. We start
932 with the approximation that its vtable is that of the
933 immediate base class. */
934 return build_primary_vtable (binfo, t);
935 else
936 /* This is our very own copy of `basetype' to play with. Later,
937 we will fill in all the virtual functions that override the
938 virtual functions in these base classes which are not defined
939 by the current type. */
940 return build_secondary_vtable (binfo);
941 }
942
943 /* Make *VIRTUALS, an entry on the BINFO_VIRTUALS list for BINFO
944 (which is in the hierarchy dominated by T) list FNDECL as its
945 BV_FN. DELTA is the required constant adjustment from the `this'
946 pointer where the vtable entry appears to the `this' required when
947 the function is actually called. */
948
949 static void
modify_vtable_entry(tree t,tree binfo,tree fndecl,tree delta,tree * virtuals)950 modify_vtable_entry (tree t,
951 tree binfo,
952 tree fndecl,
953 tree delta,
954 tree *virtuals)
955 {
956 tree v;
957
958 v = *virtuals;
959
960 if (fndecl != BV_FN (v)
961 || !tree_int_cst_equal (delta, BV_DELTA (v)))
962 {
963 /* We need a new vtable for BINFO. */
964 if (make_new_vtable (t, binfo))
965 {
966 /* If we really did make a new vtable, we also made a copy
967 of the BINFO_VIRTUALS list. Now, we have to find the
968 corresponding entry in that list. */
969 *virtuals = BINFO_VIRTUALS (binfo);
970 while (BV_FN (*virtuals) != BV_FN (v))
971 *virtuals = TREE_CHAIN (*virtuals);
972 v = *virtuals;
973 }
974
975 BV_DELTA (v) = delta;
976 BV_VCALL_INDEX (v) = NULL_TREE;
977 BV_FN (v) = fndecl;
978 }
979 }
980
981
982 /* Add method METHOD to class TYPE. If VIA_USING indicates whether
983 METHOD is being injected via a using_decl. Returns true if the
984 method could be added to the method vec. */
985
986 bool
add_method(tree type,tree method,bool via_using)987 add_method (tree type, tree method, bool via_using)
988 {
989 if (method == error_mark_node)
990 return false;
991
992 gcc_assert (!DECL_EXTERN_C_P (method));
993
994 tree *slot = find_member_slot (type, DECL_NAME (method));
995 tree current_fns = slot ? *slot : NULL_TREE;
996
997 /* Check to see if we've already got this method. */
998 for (ovl_iterator iter (current_fns); iter; ++iter)
999 {
1000 tree fn = *iter;
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 /* Two using-declarations can coexist, we'll complain about ambiguity in
1010 overload resolution. */
1011 if (via_using && iter.using_p ()
1012 /* Except handle inherited constructors specially. */
1013 && ! DECL_CONSTRUCTOR_P (fn))
1014 continue;
1015
1016 /* [over.load] Member function declarations with the
1017 same name and the same parameter types cannot be
1018 overloaded if any of them is a static member
1019 function declaration.
1020
1021 [over.load] Member function declarations with the same name and
1022 the same parameter-type-list as well as member function template
1023 declarations with the same name, the same parameter-type-list, and
1024 the same template parameter lists cannot be overloaded if any of
1025 them, but not all, have a ref-qualifier.
1026
1027 [namespace.udecl] When a using-declaration brings names
1028 from a base class into a derived class scope, member
1029 functions in the derived class override and/or hide member
1030 functions with the same name and parameter types in a base
1031 class (rather than conflicting). */
1032 fn_type = TREE_TYPE (fn);
1033 method_type = TREE_TYPE (method);
1034 parms1 = TYPE_ARG_TYPES (fn_type);
1035 parms2 = TYPE_ARG_TYPES (method_type);
1036
1037 /* Compare the quals on the 'this' parm. Don't compare
1038 the whole types, as used functions are treated as
1039 coming from the using class in overload resolution. */
1040 if (! DECL_STATIC_FUNCTION_P (fn)
1041 && ! DECL_STATIC_FUNCTION_P (method)
1042 /* Either both or neither need to be ref-qualified for
1043 differing quals to allow overloading. */
1044 && (FUNCTION_REF_QUALIFIED (fn_type)
1045 == FUNCTION_REF_QUALIFIED (method_type))
1046 && (type_memfn_quals (fn_type) != type_memfn_quals (method_type)
1047 || type_memfn_rqual (fn_type) != type_memfn_rqual (method_type)))
1048 continue;
1049
1050 /* For templates, the return type and template parameters
1051 must be identical. */
1052 if (TREE_CODE (fn) == TEMPLATE_DECL
1053 && (!same_type_p (TREE_TYPE (fn_type),
1054 TREE_TYPE (method_type))
1055 || !comp_template_parms (DECL_TEMPLATE_PARMS (fn),
1056 DECL_TEMPLATE_PARMS (method))))
1057 continue;
1058
1059 if (! DECL_STATIC_FUNCTION_P (fn))
1060 parms1 = TREE_CHAIN (parms1);
1061 if (! DECL_STATIC_FUNCTION_P (method))
1062 parms2 = TREE_CHAIN (parms2);
1063
1064 /* Bring back parameters omitted from an inherited ctor. */
1065 if (ctor_omit_inherited_parms (fn))
1066 parms1 = FUNCTION_FIRST_USER_PARMTYPE (DECL_ORIGIN (fn));
1067 if (ctor_omit_inherited_parms (method))
1068 parms2 = FUNCTION_FIRST_USER_PARMTYPE (DECL_ORIGIN (method));
1069
1070 if (compparms (parms1, parms2)
1071 && (!DECL_CONV_FN_P (fn)
1072 || same_type_p (TREE_TYPE (fn_type),
1073 TREE_TYPE (method_type)))
1074 && equivalently_constrained (fn, method))
1075 {
1076 /* If these are versions of the same function, process and
1077 move on. */
1078 if (TREE_CODE (fn) == FUNCTION_DECL
1079 && maybe_version_functions (method, fn, true))
1080 continue;
1081
1082 if (DECL_INHERITED_CTOR (method))
1083 {
1084 if (DECL_INHERITED_CTOR (fn))
1085 {
1086 tree basem = DECL_INHERITED_CTOR_BASE (method);
1087 tree basef = DECL_INHERITED_CTOR_BASE (fn);
1088 if (flag_new_inheriting_ctors)
1089 {
1090 if (basem == basef)
1091 {
1092 /* Inheriting the same constructor along different
1093 paths, combine them. */
1094 SET_DECL_INHERITED_CTOR
1095 (fn, ovl_make (DECL_INHERITED_CTOR (method),
1096 DECL_INHERITED_CTOR (fn)));
1097 /* And discard the new one. */
1098 return false;
1099 }
1100 else
1101 /* Inherited ctors can coexist until overload
1102 resolution. */
1103 continue;
1104 }
1105 error_at (DECL_SOURCE_LOCATION (method),
1106 "%q#D conflicts with version inherited from %qT",
1107 method, basef);
1108 inform (DECL_SOURCE_LOCATION (fn),
1109 "version inherited from %qT declared here",
1110 basef);
1111 }
1112 /* Otherwise defer to the other function. */
1113 return false;
1114 }
1115
1116 if (via_using)
1117 /* Defer to the local function. */
1118 return false;
1119 else if (flag_new_inheriting_ctors
1120 && DECL_INHERITED_CTOR (fn))
1121 {
1122 /* Remove the inherited constructor. */
1123 current_fns = iter.remove_node (current_fns);
1124 continue;
1125 }
1126 else
1127 {
1128 error_at (DECL_SOURCE_LOCATION (method),
1129 "%q#D cannot be overloaded with %q#D", method, fn);
1130 inform (DECL_SOURCE_LOCATION (fn),
1131 "previous declaration %q#D", fn);
1132 return false;
1133 }
1134 }
1135 }
1136
1137 current_fns = ovl_insert (method, current_fns, via_using);
1138
1139 if (!COMPLETE_TYPE_P (type) && !DECL_CONV_FN_P (method)
1140 && !push_class_level_binding (DECL_NAME (method), current_fns))
1141 return false;
1142
1143 if (!slot)
1144 slot = add_member_slot (type, DECL_NAME (method));
1145
1146 /* Maintain TYPE_HAS_USER_CONSTRUCTOR, etc. */
1147 grok_special_member_properties (method);
1148
1149 *slot = current_fns;
1150
1151 return true;
1152 }
1153
1154 /* Subroutines of finish_struct. */
1155
1156 /* Change the access of FDECL to ACCESS in T. Return 1 if change was
1157 legit, otherwise return 0. */
1158
1159 static int
alter_access(tree t,tree fdecl,tree access)1160 alter_access (tree t, tree fdecl, tree access)
1161 {
1162 tree elem;
1163
1164 retrofit_lang_decl (fdecl);
1165
1166 gcc_assert (!DECL_DISCRIMINATOR_P (fdecl));
1167
1168 elem = purpose_member (t, DECL_ACCESS (fdecl));
1169 if (elem)
1170 {
1171 if (TREE_VALUE (elem) != access)
1172 {
1173 if (TREE_CODE (TREE_TYPE (fdecl)) == FUNCTION_DECL)
1174 error ("conflicting access specifications for method"
1175 " %q+D, ignored", TREE_TYPE (fdecl));
1176 else
1177 error ("conflicting access specifications for field %qE, ignored",
1178 DECL_NAME (fdecl));
1179 }
1180 else
1181 {
1182 /* They're changing the access to the same thing they changed
1183 it to before. That's OK. */
1184 ;
1185 }
1186 }
1187 else
1188 {
1189 perform_or_defer_access_check (TYPE_BINFO (t), fdecl, fdecl,
1190 tf_warning_or_error);
1191 DECL_ACCESS (fdecl) = tree_cons (t, access, DECL_ACCESS (fdecl));
1192 return 1;
1193 }
1194 return 0;
1195 }
1196
1197 /* Return the access node for DECL's access in its enclosing class. */
1198
1199 tree
declared_access(tree decl)1200 declared_access (tree decl)
1201 {
1202 return (TREE_PRIVATE (decl) ? access_private_node
1203 : TREE_PROTECTED (decl) ? access_protected_node
1204 : access_public_node);
1205 }
1206
1207 /* Process the USING_DECL, which is a member of T. */
1208
1209 static void
handle_using_decl(tree using_decl,tree t)1210 handle_using_decl (tree using_decl, tree t)
1211 {
1212 tree decl = USING_DECL_DECLS (using_decl);
1213 tree name = DECL_NAME (using_decl);
1214 tree access = declared_access (using_decl);
1215 tree flist = NULL_TREE;
1216 tree old_value;
1217
1218 gcc_assert (!processing_template_decl && decl);
1219
1220 old_value = lookup_member (t, name, /*protect=*/0, /*want_type=*/false,
1221 tf_warning_or_error);
1222 if (old_value)
1223 {
1224 old_value = OVL_FIRST (old_value);
1225
1226 if (DECL_P (old_value) && DECL_CONTEXT (old_value) == t)
1227 /* OK */;
1228 else
1229 old_value = NULL_TREE;
1230 }
1231
1232 cp_emit_debug_info_for_using (decl, t);
1233
1234 if (is_overloaded_fn (decl))
1235 flist = decl;
1236
1237 if (! old_value)
1238 ;
1239 else if (is_overloaded_fn (old_value))
1240 {
1241 if (flist)
1242 /* It's OK to use functions from a base when there are functions with
1243 the same name already present in the current class. */;
1244 else
1245 {
1246 error_at (DECL_SOURCE_LOCATION (using_decl), "%qD invalid in %q#T "
1247 "because of local method %q#D with same name",
1248 using_decl, t, old_value);
1249 inform (DECL_SOURCE_LOCATION (old_value),
1250 "local method %q#D declared here", old_value);
1251 return;
1252 }
1253 }
1254 else if (!DECL_ARTIFICIAL (old_value))
1255 {
1256 error_at (DECL_SOURCE_LOCATION (using_decl), "%qD invalid in %q#T "
1257 "because of local member %q#D with same name",
1258 using_decl, t, old_value);
1259 inform (DECL_SOURCE_LOCATION (old_value),
1260 "local member %q#D declared here", old_value);
1261 return;
1262 }
1263
1264 /* Make type T see field decl FDECL with access ACCESS. */
1265 if (flist)
1266 for (ovl_iterator iter (flist); iter; ++iter)
1267 {
1268 add_method (t, *iter, true);
1269 alter_access (t, *iter, access);
1270 }
1271 else
1272 alter_access (t, decl, access);
1273 }
1274
1275 /* Data structure for find_abi_tags_r, below. */
1276
1277 struct abi_tag_data
1278 {
1279 tree t; // The type that we're checking for missing tags.
1280 tree subob; // The subobject of T that we're getting tags from.
1281 tree tags; // error_mark_node for diagnostics, or a list of missing tags.
1282 };
1283
1284 /* Subroutine of find_abi_tags_r. Handle a single TAG found on the class TP
1285 in the context of P. TAG can be either an identifier (the DECL_NAME of
1286 a tag NAMESPACE_DECL) or a STRING_CST (a tag attribute). */
1287
1288 static void
check_tag(tree tag,tree id,tree * tp,abi_tag_data * p)1289 check_tag (tree tag, tree id, tree *tp, abi_tag_data *p)
1290 {
1291 if (!IDENTIFIER_MARKED (id))
1292 {
1293 if (p->tags != error_mark_node)
1294 {
1295 /* We're collecting tags from template arguments or from
1296 the type of a variable or function return type. */
1297 p->tags = tree_cons (NULL_TREE, tag, p->tags);
1298
1299 /* Don't inherit this tag multiple times. */
1300 IDENTIFIER_MARKED (id) = true;
1301
1302 if (TYPE_P (p->t))
1303 {
1304 /* Tags inherited from type template arguments are only used
1305 to avoid warnings. */
1306 ABI_TAG_IMPLICIT (p->tags) = true;
1307 return;
1308 }
1309 /* For functions and variables we want to warn, too. */
1310 }
1311
1312 /* Otherwise we're diagnosing missing tags. */
1313 if (TREE_CODE (p->t) == FUNCTION_DECL)
1314 {
1315 auto_diagnostic_group d;
1316 if (warning (OPT_Wabi_tag, "%qD inherits the %E ABI tag "
1317 "that %qT (used in its return type) has",
1318 p->t, tag, *tp))
1319 inform (location_of (*tp), "%qT declared here", *tp);
1320 }
1321 else if (VAR_P (p->t))
1322 {
1323 auto_diagnostic_group d;
1324 if (warning (OPT_Wabi_tag, "%qD inherits the %E ABI tag "
1325 "that %qT (used in its type) has", p->t, tag, *tp))
1326 inform (location_of (*tp), "%qT declared here", *tp);
1327 }
1328 else if (TYPE_P (p->subob))
1329 {
1330 auto_diagnostic_group d;
1331 if (warning (OPT_Wabi_tag, "%qT does not have the %E ABI tag "
1332 "that base %qT has", p->t, tag, p->subob))
1333 inform (location_of (p->subob), "%qT declared here",
1334 p->subob);
1335 }
1336 else
1337 {
1338 auto_diagnostic_group d;
1339 if (warning (OPT_Wabi_tag, "%qT does not have the %E ABI tag "
1340 "that %qT (used in the type of %qD) has",
1341 p->t, tag, *tp, p->subob))
1342 {
1343 inform (location_of (p->subob), "%qD declared here",
1344 p->subob);
1345 inform (location_of (*tp), "%qT declared here", *tp);
1346 }
1347 }
1348 }
1349 }
1350
1351 /* Find all the ABI tags in the attribute list ATTR and either call
1352 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1353
1354 static void
mark_or_check_attr_tags(tree attr,tree * tp,abi_tag_data * p,bool val)1355 mark_or_check_attr_tags (tree attr, tree *tp, abi_tag_data *p, bool val)
1356 {
1357 if (!attr)
1358 return;
1359 for (; (attr = lookup_attribute ("abi_tag", attr));
1360 attr = TREE_CHAIN (attr))
1361 for (tree list = TREE_VALUE (attr); list;
1362 list = TREE_CHAIN (list))
1363 {
1364 tree tag = TREE_VALUE (list);
1365 tree id = get_identifier (TREE_STRING_POINTER (tag));
1366 if (tp)
1367 check_tag (tag, id, tp, p);
1368 else
1369 IDENTIFIER_MARKED (id) = val;
1370 }
1371 }
1372
1373 /* Find all the ABI tags on T and its enclosing scopes and either call
1374 check_tag (if TP is non-null) or set IDENTIFIER_MARKED to val. */
1375
1376 static void
mark_or_check_tags(tree t,tree * tp,abi_tag_data * p,bool val)1377 mark_or_check_tags (tree t, tree *tp, abi_tag_data *p, bool val)
1378 {
1379 while (t != global_namespace)
1380 {
1381 tree attr;
1382 if (TYPE_P (t))
1383 {
1384 attr = TYPE_ATTRIBUTES (t);
1385 t = CP_TYPE_CONTEXT (t);
1386 }
1387 else
1388 {
1389 attr = DECL_ATTRIBUTES (t);
1390 t = CP_DECL_CONTEXT (t);
1391 }
1392 mark_or_check_attr_tags (attr, tp, p, val);
1393 }
1394 }
1395
1396 /* walk_tree callback for check_abi_tags: if the type at *TP involves any
1397 types with ABI tags, add the corresponding identifiers to the VEC in
1398 *DATA and set IDENTIFIER_MARKED. */
1399
1400 static tree
find_abi_tags_r(tree * tp,int * walk_subtrees,void * data)1401 find_abi_tags_r (tree *tp, int *walk_subtrees, void *data)
1402 {
1403 if (!OVERLOAD_TYPE_P (*tp))
1404 return NULL_TREE;
1405
1406 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1407 anyway, but let's make sure of it. */
1408 *walk_subtrees = false;
1409
1410 abi_tag_data *p = static_cast<struct abi_tag_data*>(data);
1411
1412 mark_or_check_tags (*tp, tp, p, false);
1413
1414 return NULL_TREE;
1415 }
1416
1417 /* walk_tree callback for mark_abi_tags: if *TP is a class, set
1418 IDENTIFIER_MARKED on its ABI tags. */
1419
1420 static tree
mark_abi_tags_r(tree * tp,int * walk_subtrees,void * data)1421 mark_abi_tags_r (tree *tp, int *walk_subtrees, void *data)
1422 {
1423 if (!OVERLOAD_TYPE_P (*tp))
1424 return NULL_TREE;
1425
1426 /* walk_tree shouldn't be walking into any subtrees of a RECORD_TYPE
1427 anyway, but let's make sure of it. */
1428 *walk_subtrees = false;
1429
1430 bool *valp = static_cast<bool*>(data);
1431
1432 mark_or_check_tags (*tp, NULL, NULL, *valp);
1433
1434 return NULL_TREE;
1435 }
1436
1437 /* Set IDENTIFIER_MARKED on all the ABI tags on T and its enclosing
1438 scopes. */
1439
1440 static void
mark_abi_tags(tree t,bool val)1441 mark_abi_tags (tree t, bool val)
1442 {
1443 mark_or_check_tags (t, NULL, NULL, val);
1444 if (DECL_P (t))
1445 {
1446 if (DECL_LANG_SPECIFIC (t) && DECL_USE_TEMPLATE (t)
1447 && PRIMARY_TEMPLATE_P (DECL_TI_TEMPLATE (t)))
1448 {
1449 /* Template arguments are part of the signature. */
1450 tree level = INNERMOST_TEMPLATE_ARGS (DECL_TI_ARGS (t));
1451 for (int j = 0; j < TREE_VEC_LENGTH (level); ++j)
1452 {
1453 tree arg = TREE_VEC_ELT (level, j);
1454 cp_walk_tree_without_duplicates (&arg, mark_abi_tags_r, &val);
1455 }
1456 }
1457 if (TREE_CODE (t) == FUNCTION_DECL)
1458 /* A function's parameter types are part of the signature, so
1459 we don't need to inherit any tags that are also in them. */
1460 for (tree arg = FUNCTION_FIRST_USER_PARMTYPE (t); arg;
1461 arg = TREE_CHAIN (arg))
1462 cp_walk_tree_without_duplicates (&TREE_VALUE (arg),
1463 mark_abi_tags_r, &val);
1464 }
1465 }
1466
1467 /* Check that T has all the ABI tags that subobject SUBOB has, or
1468 warn if not. If T is a (variable or function) declaration, also
1469 return any missing tags, and add them to T if JUST_CHECKING is false. */
1470
1471 static tree
1472 check_abi_tags (tree t, tree subob, bool just_checking = false)
1473 {
1474 bool inherit = DECL_P (t);
1475
1476 if (!inherit && !warn_abi_tag)
1477 return NULL_TREE;
1478
1479 tree decl = TYPE_P (t) ? TYPE_NAME (t) : t;
1480 if (!TREE_PUBLIC (decl))
1481 /* No need to worry about things local to this TU. */
1482 return NULL_TREE;
1483
1484 mark_abi_tags (t, true);
1485
1486 tree subtype = TYPE_P (subob) ? subob : TREE_TYPE (subob);
1487 struct abi_tag_data data = { t, subob, error_mark_node };
1488 if (inherit)
1489 data.tags = NULL_TREE;
1490
1491 cp_walk_tree_without_duplicates (&subtype, find_abi_tags_r, &data);
1492
1493 if (!(inherit && data.tags))
1494 /* We don't need to do anything with data.tags. */;
1495 else if (just_checking)
1496 for (tree t = data.tags; t; t = TREE_CHAIN (t))
1497 {
1498 tree id = get_identifier (TREE_STRING_POINTER (TREE_VALUE (t)));
1499 IDENTIFIER_MARKED (id) = false;
1500 }
1501 else
1502 {
1503 tree attr = lookup_attribute ("abi_tag", DECL_ATTRIBUTES (t));
1504 if (attr)
1505 TREE_VALUE (attr) = chainon (data.tags, TREE_VALUE (attr));
1506 else
1507 DECL_ATTRIBUTES (t)
1508 = tree_cons (abi_tag_identifier, data.tags, DECL_ATTRIBUTES (t));
1509 }
1510
1511 mark_abi_tags (t, false);
1512
1513 return data.tags;
1514 }
1515
1516 /* Check that DECL has all the ABI tags that are used in parts of its type
1517 that are not reflected in its mangled name. */
1518
1519 void
check_abi_tags(tree decl)1520 check_abi_tags (tree decl)
1521 {
1522 if (VAR_P (decl))
1523 check_abi_tags (decl, TREE_TYPE (decl));
1524 else if (TREE_CODE (decl) == FUNCTION_DECL
1525 && !DECL_CONV_FN_P (decl)
1526 && !mangle_return_type_p (decl))
1527 check_abi_tags (decl, TREE_TYPE (TREE_TYPE (decl)));
1528 }
1529
1530 /* Return any ABI tags that are used in parts of the type of DECL
1531 that are not reflected in its mangled name. This function is only
1532 used in backward-compatible mangling for ABI <11. */
1533
1534 tree
missing_abi_tags(tree decl)1535 missing_abi_tags (tree decl)
1536 {
1537 if (VAR_P (decl))
1538 return check_abi_tags (decl, TREE_TYPE (decl), true);
1539 else if (TREE_CODE (decl) == FUNCTION_DECL
1540 /* Don't check DECL_CONV_FN_P here like we do in check_abi_tags, so
1541 that we can use this function for setting need_abi_warning
1542 regardless of the current flag_abi_version. */
1543 && !mangle_return_type_p (decl))
1544 return check_abi_tags (decl, TREE_TYPE (TREE_TYPE (decl)), true);
1545 else
1546 return NULL_TREE;
1547 }
1548
1549 void
inherit_targ_abi_tags(tree t)1550 inherit_targ_abi_tags (tree t)
1551 {
1552 if (!CLASS_TYPE_P (t)
1553 || CLASSTYPE_TEMPLATE_INFO (t) == NULL_TREE)
1554 return;
1555
1556 mark_abi_tags (t, true);
1557
1558 tree args = CLASSTYPE_TI_ARGS (t);
1559 struct abi_tag_data data = { t, NULL_TREE, NULL_TREE };
1560 for (int i = 0; i < TMPL_ARGS_DEPTH (args); ++i)
1561 {
1562 tree level = TMPL_ARGS_LEVEL (args, i+1);
1563 for (int j = 0; j < TREE_VEC_LENGTH (level); ++j)
1564 {
1565 tree arg = TREE_VEC_ELT (level, j);
1566 data.subob = arg;
1567 cp_walk_tree_without_duplicates (&arg, find_abi_tags_r, &data);
1568 }
1569 }
1570
1571 // If we found some tags on our template arguments, add them to our
1572 // abi_tag attribute.
1573 if (data.tags)
1574 {
1575 tree attr = lookup_attribute ("abi_tag", TYPE_ATTRIBUTES (t));
1576 if (attr)
1577 TREE_VALUE (attr) = chainon (data.tags, TREE_VALUE (attr));
1578 else
1579 TYPE_ATTRIBUTES (t)
1580 = tree_cons (abi_tag_identifier, data.tags, TYPE_ATTRIBUTES (t));
1581 }
1582
1583 mark_abi_tags (t, false);
1584 }
1585
1586 /* Return true, iff class T has a non-virtual destructor that is
1587 accessible from outside the class heirarchy (i.e. is public, or
1588 there's a suitable friend. */
1589
1590 static bool
accessible_nvdtor_p(tree t)1591 accessible_nvdtor_p (tree t)
1592 {
1593 tree dtor = CLASSTYPE_DESTRUCTOR (t);
1594
1595 /* An implicitly declared destructor is always public. And,
1596 if it were virtual, we would have created it by now. */
1597 if (!dtor)
1598 return true;
1599
1600 if (DECL_VINDEX (dtor))
1601 return false; /* Virtual */
1602
1603 if (!TREE_PRIVATE (dtor) && !TREE_PROTECTED (dtor))
1604 return true; /* Public */
1605
1606 if (CLASSTYPE_FRIEND_CLASSES (t)
1607 || DECL_FRIENDLIST (TYPE_MAIN_DECL (t)))
1608 return true; /* Has friends */
1609
1610 return false;
1611 }
1612
1613 /* Run through the base classes of T, updating CANT_HAVE_CONST_CTOR_P,
1614 and NO_CONST_ASN_REF_P. Also set flag bits in T based on
1615 properties of the bases. */
1616
1617 static void
check_bases(tree t,int * cant_have_const_ctor_p,int * no_const_asn_ref_p)1618 check_bases (tree t,
1619 int* cant_have_const_ctor_p,
1620 int* no_const_asn_ref_p)
1621 {
1622 int i;
1623 bool seen_non_virtual_nearly_empty_base_p = 0;
1624 int seen_tm_mask = 0;
1625 tree base_binfo;
1626 tree binfo;
1627 tree field = NULL_TREE;
1628
1629 if (!CLASSTYPE_NON_STD_LAYOUT (t))
1630 for (field = TYPE_FIELDS (t); field; field = DECL_CHAIN (field))
1631 if (TREE_CODE (field) == FIELD_DECL)
1632 break;
1633
1634 for (binfo = TYPE_BINFO (t), i = 0;
1635 BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
1636 {
1637 tree basetype = TREE_TYPE (base_binfo);
1638
1639 gcc_assert (COMPLETE_TYPE_P (basetype));
1640
1641 if (CLASSTYPE_FINAL (basetype))
1642 error ("cannot derive from %<final%> base %qT in derived type %qT",
1643 basetype, t);
1644
1645 /* If any base class is non-literal, so is the derived class. */
1646 if (!CLASSTYPE_LITERAL_P (basetype))
1647 CLASSTYPE_LITERAL_P (t) = false;
1648
1649 /* If the base class doesn't have copy constructors or
1650 assignment operators that take const references, then the
1651 derived class cannot have such a member automatically
1652 generated. */
1653 if (TYPE_HAS_COPY_CTOR (basetype)
1654 && ! TYPE_HAS_CONST_COPY_CTOR (basetype))
1655 *cant_have_const_ctor_p = 1;
1656 if (TYPE_HAS_COPY_ASSIGN (basetype)
1657 && !TYPE_HAS_CONST_COPY_ASSIGN (basetype))
1658 *no_const_asn_ref_p = 1;
1659
1660 if (BINFO_VIRTUAL_P (base_binfo))
1661 /* A virtual base does not effect nearly emptiness. */
1662 ;
1663 else if (CLASSTYPE_NEARLY_EMPTY_P (basetype))
1664 {
1665 if (seen_non_virtual_nearly_empty_base_p)
1666 /* And if there is more than one nearly empty base, then the
1667 derived class is not nearly empty either. */
1668 CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
1669 else
1670 /* Remember we've seen one. */
1671 seen_non_virtual_nearly_empty_base_p = 1;
1672 }
1673 else if (!is_empty_class (basetype))
1674 /* If the base class is not empty or nearly empty, then this
1675 class cannot be nearly empty. */
1676 CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
1677
1678 /* A lot of properties from the bases also apply to the derived
1679 class. */
1680 TYPE_NEEDS_CONSTRUCTING (t) |= TYPE_NEEDS_CONSTRUCTING (basetype);
1681 TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t)
1682 |= TYPE_HAS_NONTRIVIAL_DESTRUCTOR (basetype);
1683 TYPE_HAS_COMPLEX_COPY_ASSIGN (t)
1684 |= (TYPE_HAS_COMPLEX_COPY_ASSIGN (basetype)
1685 || !TYPE_HAS_COPY_ASSIGN (basetype));
1686 TYPE_HAS_COMPLEX_COPY_CTOR (t) |= (TYPE_HAS_COMPLEX_COPY_CTOR (basetype)
1687 || !TYPE_HAS_COPY_CTOR (basetype));
1688 TYPE_HAS_COMPLEX_MOVE_ASSIGN (t)
1689 |= TYPE_HAS_COMPLEX_MOVE_ASSIGN (basetype);
1690 TYPE_HAS_COMPLEX_MOVE_CTOR (t) |= TYPE_HAS_COMPLEX_MOVE_CTOR (basetype);
1691 TYPE_POLYMORPHIC_P (t) |= TYPE_POLYMORPHIC_P (basetype);
1692 CLASSTYPE_CONTAINS_EMPTY_CLASS_P (t)
1693 |= CLASSTYPE_CONTAINS_EMPTY_CLASS_P (basetype);
1694 TYPE_HAS_COMPLEX_DFLT (t) |= (!TYPE_HAS_DEFAULT_CONSTRUCTOR (basetype)
1695 || TYPE_HAS_COMPLEX_DFLT (basetype));
1696 SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT
1697 (t, CLASSTYPE_READONLY_FIELDS_NEED_INIT (t)
1698 | CLASSTYPE_READONLY_FIELDS_NEED_INIT (basetype));
1699 SET_CLASSTYPE_REF_FIELDS_NEED_INIT
1700 (t, CLASSTYPE_REF_FIELDS_NEED_INIT (t)
1701 | CLASSTYPE_REF_FIELDS_NEED_INIT (basetype));
1702 if (TYPE_HAS_MUTABLE_P (basetype))
1703 CLASSTYPE_HAS_MUTABLE (t) = 1;
1704
1705 /* A standard-layout class is a class that:
1706 ...
1707 * has no non-standard-layout base classes, */
1708 CLASSTYPE_NON_STD_LAYOUT (t) |= CLASSTYPE_NON_STD_LAYOUT (basetype);
1709 if (!CLASSTYPE_NON_STD_LAYOUT (t))
1710 {
1711 tree basefield;
1712 /* ...has no base classes of the same type as the first non-static
1713 data member... */
1714 if (field && DECL_CONTEXT (field) == t
1715 && (same_type_ignoring_top_level_qualifiers_p
1716 (TREE_TYPE (field), basetype)))
1717 CLASSTYPE_NON_STD_LAYOUT (t) = 1;
1718 else
1719 /* ...either has no non-static data members in the most-derived
1720 class and at most one base class with non-static data
1721 members, or has no base classes with non-static data
1722 members */
1723 for (basefield = TYPE_FIELDS (basetype); basefield;
1724 basefield = DECL_CHAIN (basefield))
1725 if (TREE_CODE (basefield) == FIELD_DECL
1726 && !(DECL_FIELD_IS_BASE (basefield)
1727 && integer_zerop (DECL_SIZE (basefield))))
1728 {
1729 if (field)
1730 CLASSTYPE_NON_STD_LAYOUT (t) = 1;
1731 else
1732 field = basefield;
1733 break;
1734 }
1735 }
1736
1737 /* Don't bother collecting tm attributes if transactional memory
1738 support is not enabled. */
1739 if (flag_tm)
1740 {
1741 tree tm_attr = find_tm_attribute (TYPE_ATTRIBUTES (basetype));
1742 if (tm_attr)
1743 seen_tm_mask |= tm_attr_to_mask (tm_attr);
1744 }
1745
1746 check_abi_tags (t, basetype);
1747 }
1748
1749 /* If one of the base classes had TM attributes, and the current class
1750 doesn't define its own, then the current class inherits one. */
1751 if (seen_tm_mask && !find_tm_attribute (TYPE_ATTRIBUTES (t)))
1752 {
1753 tree tm_attr = tm_mask_to_attr (least_bit_hwi (seen_tm_mask));
1754 TYPE_ATTRIBUTES (t) = tree_cons (tm_attr, NULL, TYPE_ATTRIBUTES (t));
1755 }
1756 }
1757
1758 /* Determine all the primary bases within T. Sets BINFO_PRIMARY_BASE_P for
1759 those that are primaries. Sets BINFO_LOST_PRIMARY_P for those
1760 that have had a nearly-empty virtual primary base stolen by some
1761 other base in the hierarchy. Determines CLASSTYPE_PRIMARY_BASE for
1762 T. */
1763
1764 static void
determine_primary_bases(tree t)1765 determine_primary_bases (tree t)
1766 {
1767 unsigned i;
1768 tree primary = NULL_TREE;
1769 tree type_binfo = TYPE_BINFO (t);
1770 tree base_binfo;
1771
1772 /* Determine the primary bases of our bases. */
1773 for (base_binfo = TREE_CHAIN (type_binfo); base_binfo;
1774 base_binfo = TREE_CHAIN (base_binfo))
1775 {
1776 tree primary = CLASSTYPE_PRIMARY_BINFO (BINFO_TYPE (base_binfo));
1777
1778 /* See if we're the non-virtual primary of our inheritance
1779 chain. */
1780 if (!BINFO_VIRTUAL_P (base_binfo))
1781 {
1782 tree parent = BINFO_INHERITANCE_CHAIN (base_binfo);
1783 tree parent_primary = CLASSTYPE_PRIMARY_BINFO (BINFO_TYPE (parent));
1784
1785 if (parent_primary
1786 && SAME_BINFO_TYPE_P (BINFO_TYPE (base_binfo),
1787 BINFO_TYPE (parent_primary)))
1788 /* We are the primary binfo. */
1789 BINFO_PRIMARY_P (base_binfo) = 1;
1790 }
1791 /* Determine if we have a virtual primary base, and mark it so.
1792 */
1793 if (primary && BINFO_VIRTUAL_P (primary))
1794 {
1795 tree this_primary = copied_binfo (primary, base_binfo);
1796
1797 if (BINFO_PRIMARY_P (this_primary))
1798 /* Someone already claimed this base. */
1799 BINFO_LOST_PRIMARY_P (base_binfo) = 1;
1800 else
1801 {
1802 tree delta;
1803
1804 BINFO_PRIMARY_P (this_primary) = 1;
1805 BINFO_INHERITANCE_CHAIN (this_primary) = base_binfo;
1806
1807 /* A virtual binfo might have been copied from within
1808 another hierarchy. As we're about to use it as a
1809 primary base, make sure the offsets match. */
1810 delta = size_diffop_loc (input_location,
1811 fold_convert (ssizetype,
1812 BINFO_OFFSET (base_binfo)),
1813 fold_convert (ssizetype,
1814 BINFO_OFFSET (this_primary)));
1815
1816 propagate_binfo_offsets (this_primary, delta);
1817 }
1818 }
1819 }
1820
1821 /* First look for a dynamic direct non-virtual base. */
1822 for (i = 0; BINFO_BASE_ITERATE (type_binfo, i, base_binfo); i++)
1823 {
1824 tree basetype = BINFO_TYPE (base_binfo);
1825
1826 if (TYPE_CONTAINS_VPTR_P (basetype) && !BINFO_VIRTUAL_P (base_binfo))
1827 {
1828 primary = base_binfo;
1829 goto found;
1830 }
1831 }
1832
1833 /* A "nearly-empty" virtual base class can be the primary base
1834 class, if no non-virtual polymorphic base can be found. Look for
1835 a nearly-empty virtual dynamic base that is not already a primary
1836 base of something in the hierarchy. If there is no such base,
1837 just pick the first nearly-empty virtual base. */
1838
1839 for (base_binfo = TREE_CHAIN (type_binfo); base_binfo;
1840 base_binfo = TREE_CHAIN (base_binfo))
1841 if (BINFO_VIRTUAL_P (base_binfo)
1842 && CLASSTYPE_NEARLY_EMPTY_P (BINFO_TYPE (base_binfo)))
1843 {
1844 if (!BINFO_PRIMARY_P (base_binfo))
1845 {
1846 /* Found one that is not primary. */
1847 primary = base_binfo;
1848 goto found;
1849 }
1850 else if (!primary)
1851 /* Remember the first candidate. */
1852 primary = base_binfo;
1853 }
1854
1855 found:
1856 /* If we've got a primary base, use it. */
1857 if (primary)
1858 {
1859 tree basetype = BINFO_TYPE (primary);
1860
1861 CLASSTYPE_PRIMARY_BINFO (t) = primary;
1862 if (BINFO_PRIMARY_P (primary))
1863 /* We are stealing a primary base. */
1864 BINFO_LOST_PRIMARY_P (BINFO_INHERITANCE_CHAIN (primary)) = 1;
1865 BINFO_PRIMARY_P (primary) = 1;
1866 if (BINFO_VIRTUAL_P (primary))
1867 {
1868 tree delta;
1869
1870 BINFO_INHERITANCE_CHAIN (primary) = type_binfo;
1871 /* A virtual binfo might have been copied from within
1872 another hierarchy. As we're about to use it as a primary
1873 base, make sure the offsets match. */
1874 delta = size_diffop_loc (input_location, ssize_int (0),
1875 fold_convert (ssizetype, BINFO_OFFSET (primary)));
1876
1877 propagate_binfo_offsets (primary, delta);
1878 }
1879
1880 primary = TYPE_BINFO (basetype);
1881
1882 TYPE_VFIELD (t) = TYPE_VFIELD (basetype);
1883 BINFO_VTABLE (type_binfo) = BINFO_VTABLE (primary);
1884 BINFO_VIRTUALS (type_binfo) = BINFO_VIRTUALS (primary);
1885 }
1886 }
1887
1888 /* Update the variant types of T. */
1889
1890 void
fixup_type_variants(tree t)1891 fixup_type_variants (tree t)
1892 {
1893 tree variants;
1894
1895 if (!t)
1896 return;
1897
1898 for (variants = TYPE_NEXT_VARIANT (t);
1899 variants;
1900 variants = TYPE_NEXT_VARIANT (variants))
1901 {
1902 /* These fields are in the _TYPE part of the node, not in
1903 the TYPE_LANG_SPECIFIC component, so they are not shared. */
1904 TYPE_HAS_USER_CONSTRUCTOR (variants) = TYPE_HAS_USER_CONSTRUCTOR (t);
1905 TYPE_NEEDS_CONSTRUCTING (variants) = TYPE_NEEDS_CONSTRUCTING (t);
1906 TYPE_HAS_NONTRIVIAL_DESTRUCTOR (variants)
1907 = TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t);
1908
1909 TYPE_POLYMORPHIC_P (variants) = TYPE_POLYMORPHIC_P (t);
1910
1911 TYPE_BINFO (variants) = TYPE_BINFO (t);
1912
1913 /* Copy whatever these are holding today. */
1914 TYPE_VFIELD (variants) = TYPE_VFIELD (t);
1915 TYPE_FIELDS (variants) = TYPE_FIELDS (t);
1916 }
1917 }
1918
1919 /* KLASS is a class that we're applying may_alias to after the body is
1920 parsed. Fixup any POINTER_TO and REFERENCE_TO types. The
1921 canonical type(s) will be implicitly updated. */
1922
1923 static void
fixup_may_alias(tree klass)1924 fixup_may_alias (tree klass)
1925 {
1926 tree t, v;
1927
1928 for (t = TYPE_POINTER_TO (klass); t; t = TYPE_NEXT_PTR_TO (t))
1929 for (v = TYPE_MAIN_VARIANT (t); v; v = TYPE_NEXT_VARIANT (v))
1930 TYPE_REF_CAN_ALIAS_ALL (v) = true;
1931 for (t = TYPE_REFERENCE_TO (klass); t; t = TYPE_NEXT_REF_TO (t))
1932 for (v = TYPE_MAIN_VARIANT (t); v; v = TYPE_NEXT_VARIANT (v))
1933 TYPE_REF_CAN_ALIAS_ALL (v) = true;
1934 }
1935
1936 /* Early variant fixups: we apply attributes at the beginning of the class
1937 definition, and we need to fix up any variants that have already been
1938 made via elaborated-type-specifier so that check_qualified_type works. */
1939
1940 void
fixup_attribute_variants(tree t)1941 fixup_attribute_variants (tree t)
1942 {
1943 tree variants;
1944
1945 if (!t)
1946 return;
1947
1948 tree attrs = TYPE_ATTRIBUTES (t);
1949 unsigned align = TYPE_ALIGN (t);
1950 bool user_align = TYPE_USER_ALIGN (t);
1951 bool may_alias = lookup_attribute ("may_alias", attrs);
1952 bool packed = TYPE_PACKED (t);
1953
1954 if (may_alias)
1955 fixup_may_alias (t);
1956
1957 for (variants = TYPE_NEXT_VARIANT (t);
1958 variants;
1959 variants = TYPE_NEXT_VARIANT (variants))
1960 {
1961 /* These are the two fields that check_qualified_type looks at and
1962 are affected by attributes. */
1963 TYPE_ATTRIBUTES (variants) = attrs;
1964 unsigned valign = align;
1965 if (TYPE_USER_ALIGN (variants))
1966 valign = MAX (valign, TYPE_ALIGN (variants));
1967 else
1968 TYPE_USER_ALIGN (variants) = user_align;
1969 SET_TYPE_ALIGN (variants, valign);
1970 TYPE_PACKED (variants) = packed;
1971 if (may_alias)
1972 fixup_may_alias (variants);
1973 }
1974 }
1975
1976 /* Set memoizing fields and bits of T (and its variants) for later
1977 use. */
1978
1979 static void
finish_struct_bits(tree t)1980 finish_struct_bits (tree t)
1981 {
1982 /* Fix up variants (if any). */
1983 fixup_type_variants (t);
1984
1985 if (BINFO_N_BASE_BINFOS (TYPE_BINFO (t)) && TYPE_POLYMORPHIC_P (t))
1986 /* For a class w/o baseclasses, 'finish_struct' has set
1987 CLASSTYPE_PURE_VIRTUALS correctly (by definition).
1988 Similarly for a class whose base classes do not have vtables.
1989 When neither of these is true, we might have removed abstract
1990 virtuals (by providing a definition), added some (by declaring
1991 new ones), or redeclared ones from a base class. We need to
1992 recalculate what's really an abstract virtual at this point (by
1993 looking in the vtables). */
1994 get_pure_virtuals (t);
1995
1996 /* If this type has a copy constructor or a destructor, force its
1997 mode to be BLKmode, and force its TREE_ADDRESSABLE bit to be
1998 nonzero. This will cause it to be passed by invisible reference
1999 and prevent it from being returned in a register. */
2000 if (type_has_nontrivial_copy_init (t)
2001 || TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t))
2002 {
2003 tree variants;
2004 SET_DECL_MODE (TYPE_MAIN_DECL (t), BLKmode);
2005 for (variants = t; variants; variants = TYPE_NEXT_VARIANT (variants))
2006 {
2007 SET_TYPE_MODE (variants, BLKmode);
2008 TREE_ADDRESSABLE (variants) = 1;
2009 }
2010 }
2011 }
2012
2013 /* Issue warnings about T having private constructors, but no friends,
2014 and so forth.
2015
2016 HAS_NONPRIVATE_METHOD is nonzero if T has any non-private methods or
2017 static members. HAS_NONPRIVATE_STATIC_FN is nonzero if T has any
2018 non-private static member functions. */
2019
2020 static void
maybe_warn_about_overly_private_class(tree t)2021 maybe_warn_about_overly_private_class (tree t)
2022 {
2023 int has_member_fn = 0;
2024 int has_nonprivate_method = 0;
2025 bool nonprivate_ctor = false;
2026
2027 if (!warn_ctor_dtor_privacy
2028 /* If the class has friends, those entities might create and
2029 access instances, so we should not warn. */
2030 || (CLASSTYPE_FRIEND_CLASSES (t)
2031 || DECL_FRIENDLIST (TYPE_MAIN_DECL (t)))
2032 /* We will have warned when the template was declared; there's
2033 no need to warn on every instantiation. */
2034 || CLASSTYPE_TEMPLATE_INSTANTIATION (t))
2035 /* There's no reason to even consider warning about this
2036 class. */
2037 return;
2038
2039 /* We only issue one warning, if more than one applies, because
2040 otherwise, on code like:
2041
2042 class A {
2043 // Oops - forgot `public:'
2044 A();
2045 A(const A&);
2046 ~A();
2047 };
2048
2049 we warn several times about essentially the same problem. */
2050
2051 /* Check to see if all (non-constructor, non-destructor) member
2052 functions are private. (Since there are no friends or
2053 non-private statics, we can't ever call any of the private member
2054 functions.) */
2055 for (tree fn = TYPE_FIELDS (t); fn; fn = DECL_CHAIN (fn))
2056 if (TREE_CODE (fn) == USING_DECL
2057 && DECL_NAME (fn) == ctor_identifier
2058 && !TREE_PRIVATE (fn))
2059 nonprivate_ctor = true;
2060 else if (!DECL_DECLARES_FUNCTION_P (fn))
2061 /* Not a function. */;
2062 else if (DECL_ARTIFICIAL (fn))
2063 /* We're not interested in compiler-generated methods; they don't
2064 provide any way to call private members. */;
2065 else if (!TREE_PRIVATE (fn))
2066 {
2067 if (DECL_STATIC_FUNCTION_P (fn))
2068 /* A non-private static member function is just like a
2069 friend; it can create and invoke private member
2070 functions, and be accessed without a class
2071 instance. */
2072 return;
2073
2074 has_nonprivate_method = 1;
2075 /* Keep searching for a static member function. */
2076 }
2077 else if (!DECL_CONSTRUCTOR_P (fn) && !DECL_DESTRUCTOR_P (fn))
2078 has_member_fn = 1;
2079
2080 if (!has_nonprivate_method && has_member_fn)
2081 {
2082 /* There are no non-private methods, and there's at least one
2083 private member function that isn't a constructor or
2084 destructor. (If all the private members are
2085 constructors/destructors we want to use the code below that
2086 issues error messages specifically referring to
2087 constructors/destructors.) */
2088 unsigned i;
2089 tree binfo = TYPE_BINFO (t);
2090
2091 for (i = 0; i != BINFO_N_BASE_BINFOS (binfo); i++)
2092 if (BINFO_BASE_ACCESS (binfo, i) != access_private_node)
2093 {
2094 has_nonprivate_method = 1;
2095 break;
2096 }
2097 if (!has_nonprivate_method)
2098 {
2099 warning (OPT_Wctor_dtor_privacy,
2100 "all member functions in class %qT are private", t);
2101 return;
2102 }
2103 }
2104
2105 /* Even if some of the member functions are non-private, the class
2106 won't be useful for much if all the constructors or destructors
2107 are private: such an object can never be created or destroyed. */
2108 if (tree dtor = CLASSTYPE_DESTRUCTOR (t))
2109 if (TREE_PRIVATE (dtor))
2110 {
2111 warning (OPT_Wctor_dtor_privacy,
2112 "%q#T only defines a private destructor and has no friends",
2113 t);
2114 return;
2115 }
2116
2117 /* Warn about classes that have private constructors and no friends. */
2118 if (TYPE_HAS_USER_CONSTRUCTOR (t)
2119 /* Implicitly generated constructors are always public. */
2120 && !CLASSTYPE_LAZY_DEFAULT_CTOR (t))
2121 {
2122 tree copy_or_move = NULL_TREE;
2123
2124 /* If a non-template class does not define a copy
2125 constructor, one is defined for it, enabling it to avoid
2126 this warning. For a template class, this does not
2127 happen, and so we would normally get a warning on:
2128
2129 template <class T> class C { private: C(); };
2130
2131 To avoid this asymmetry, we check TYPE_HAS_COPY_CTOR. All
2132 complete non-template or fully instantiated classes have this
2133 flag set. */
2134 if (!TYPE_HAS_COPY_CTOR (t))
2135 nonprivate_ctor = true;
2136 else
2137 for (ovl_iterator iter (CLASSTYPE_CONSTRUCTORS (t));
2138 !nonprivate_ctor && iter; ++iter)
2139 if (TREE_PRIVATE (*iter))
2140 continue;
2141 else if (copy_fn_p (*iter) || move_fn_p (*iter))
2142 /* Ideally, we wouldn't count any constructor that takes
2143 an argument of the class type as a parameter, because
2144 such things cannot be used to construct an instance of
2145 the class unless you already have one. */
2146 copy_or_move = *iter;
2147 else
2148 nonprivate_ctor = true;
2149
2150 if (!nonprivate_ctor)
2151 {
2152 warning (OPT_Wctor_dtor_privacy,
2153 "%q#T only defines private constructors and has no friends",
2154 t);
2155 if (copy_or_move)
2156 inform (DECL_SOURCE_LOCATION (copy_or_move),
2157 "%q#D is public, but requires an existing %q#T object",
2158 copy_or_move, t);
2159 return;
2160 }
2161 }
2162 }
2163
2164 /* Make BINFO's vtable have N entries, including RTTI entries,
2165 vbase and vcall offsets, etc. Set its type and call the back end
2166 to lay it out. */
2167
2168 static void
layout_vtable_decl(tree binfo,int n)2169 layout_vtable_decl (tree binfo, int n)
2170 {
2171 tree atype;
2172 tree vtable;
2173
2174 atype = build_array_of_n_type (vtable_entry_type, n);
2175 layout_type (atype);
2176
2177 /* We may have to grow the vtable. */
2178 vtable = get_vtbl_decl_for_binfo (binfo);
2179 if (!same_type_p (TREE_TYPE (vtable), atype))
2180 {
2181 TREE_TYPE (vtable) = atype;
2182 DECL_SIZE (vtable) = DECL_SIZE_UNIT (vtable) = NULL_TREE;
2183 layout_decl (vtable, 0);
2184 }
2185 }
2186
2187 /* True iff FNDECL and BASE_FNDECL (both non-static member functions)
2188 have the same signature. */
2189
2190 int
same_signature_p(const_tree fndecl,const_tree base_fndecl)2191 same_signature_p (const_tree fndecl, const_tree base_fndecl)
2192 {
2193 /* One destructor overrides another if they are the same kind of
2194 destructor. */
2195 if (DECL_DESTRUCTOR_P (base_fndecl) && DECL_DESTRUCTOR_P (fndecl)
2196 && special_function_p (base_fndecl) == special_function_p (fndecl))
2197 return 1;
2198 /* But a non-destructor never overrides a destructor, nor vice
2199 versa, nor do different kinds of destructors override
2200 one-another. For example, a complete object destructor does not
2201 override a deleting destructor. */
2202 if (DECL_DESTRUCTOR_P (base_fndecl) || DECL_DESTRUCTOR_P (fndecl))
2203 return 0;
2204
2205 if (DECL_NAME (fndecl) == DECL_NAME (base_fndecl)
2206 || (DECL_CONV_FN_P (fndecl)
2207 && DECL_CONV_FN_P (base_fndecl)
2208 && same_type_p (DECL_CONV_FN_TYPE (fndecl),
2209 DECL_CONV_FN_TYPE (base_fndecl))))
2210 {
2211 tree fntype = TREE_TYPE (fndecl);
2212 tree base_fntype = TREE_TYPE (base_fndecl);
2213 if (type_memfn_quals (fntype) == type_memfn_quals (base_fntype)
2214 && type_memfn_rqual (fntype) == type_memfn_rqual (base_fntype)
2215 && compparms (FUNCTION_FIRST_USER_PARMTYPE (fndecl),
2216 FUNCTION_FIRST_USER_PARMTYPE (base_fndecl)))
2217 return 1;
2218 }
2219 return 0;
2220 }
2221
2222 /* Returns TRUE if DERIVED is a binfo containing the binfo BASE as a
2223 subobject. */
2224
2225 static bool
base_derived_from(tree derived,tree base)2226 base_derived_from (tree derived, tree base)
2227 {
2228 tree probe;
2229
2230 for (probe = base; probe; probe = BINFO_INHERITANCE_CHAIN (probe))
2231 {
2232 if (probe == derived)
2233 return true;
2234 else if (BINFO_VIRTUAL_P (probe))
2235 /* If we meet a virtual base, we can't follow the inheritance
2236 any more. See if the complete type of DERIVED contains
2237 such a virtual base. */
2238 return (binfo_for_vbase (BINFO_TYPE (probe), BINFO_TYPE (derived))
2239 != NULL_TREE);
2240 }
2241 return false;
2242 }
2243
2244 struct find_final_overrider_data {
2245 /* The function for which we are trying to find a final overrider. */
2246 tree fn;
2247 /* The base class in which the function was declared. */
2248 tree declaring_base;
2249 /* The candidate overriders. */
2250 tree candidates;
2251 /* Path to most derived. */
2252 vec<tree> path;
2253 };
2254
2255 /* Add the overrider along the current path to FFOD->CANDIDATES.
2256 Returns true if an overrider was found; false otherwise. */
2257
2258 static bool
dfs_find_final_overrider_1(tree binfo,find_final_overrider_data * ffod,unsigned depth)2259 dfs_find_final_overrider_1 (tree binfo,
2260 find_final_overrider_data *ffod,
2261 unsigned depth)
2262 {
2263 tree method;
2264
2265 /* If BINFO is not the most derived type, try a more derived class.
2266 A definition there will overrider a definition here. */
2267 if (depth)
2268 {
2269 depth--;
2270 if (dfs_find_final_overrider_1
2271 (ffod->path[depth], ffod, depth))
2272 return true;
2273 }
2274
2275 method = look_for_overrides_here (BINFO_TYPE (binfo), ffod->fn);
2276 if (method)
2277 {
2278 tree *candidate = &ffod->candidates;
2279
2280 /* Remove any candidates overridden by this new function. */
2281 while (*candidate)
2282 {
2283 /* If *CANDIDATE overrides METHOD, then METHOD
2284 cannot override anything else on the list. */
2285 if (base_derived_from (TREE_VALUE (*candidate), binfo))
2286 return true;
2287 /* If METHOD overrides *CANDIDATE, remove *CANDIDATE. */
2288 if (base_derived_from (binfo, TREE_VALUE (*candidate)))
2289 *candidate = TREE_CHAIN (*candidate);
2290 else
2291 candidate = &TREE_CHAIN (*candidate);
2292 }
2293
2294 /* Add the new function. */
2295 ffod->candidates = tree_cons (method, binfo, ffod->candidates);
2296 return true;
2297 }
2298
2299 return false;
2300 }
2301
2302 /* Called from find_final_overrider via dfs_walk. */
2303
2304 static tree
dfs_find_final_overrider_pre(tree binfo,void * data)2305 dfs_find_final_overrider_pre (tree binfo, void *data)
2306 {
2307 find_final_overrider_data *ffod = (find_final_overrider_data *) data;
2308
2309 if (binfo == ffod->declaring_base)
2310 dfs_find_final_overrider_1 (binfo, ffod, ffod->path.length ());
2311 ffod->path.safe_push (binfo);
2312
2313 return NULL_TREE;
2314 }
2315
2316 static tree
dfs_find_final_overrider_post(tree,void * data)2317 dfs_find_final_overrider_post (tree /*binfo*/, void *data)
2318 {
2319 find_final_overrider_data *ffod = (find_final_overrider_data *) data;
2320 ffod->path.pop ();
2321
2322 return NULL_TREE;
2323 }
2324
2325 /* Returns a TREE_LIST whose TREE_PURPOSE is the final overrider for
2326 FN and whose TREE_VALUE is the binfo for the base where the
2327 overriding occurs. BINFO (in the hierarchy dominated by the binfo
2328 DERIVED) is the base object in which FN is declared. */
2329
2330 static tree
find_final_overrider(tree derived,tree binfo,tree fn)2331 find_final_overrider (tree derived, tree binfo, tree fn)
2332 {
2333 find_final_overrider_data ffod;
2334
2335 /* Getting this right is a little tricky. This is valid:
2336
2337 struct S { virtual void f (); };
2338 struct T { virtual void f (); };
2339 struct U : public S, public T { };
2340
2341 even though calling `f' in `U' is ambiguous. But,
2342
2343 struct R { virtual void f(); };
2344 struct S : virtual public R { virtual void f (); };
2345 struct T : virtual public R { virtual void f (); };
2346 struct U : public S, public T { };
2347
2348 is not -- there's no way to decide whether to put `S::f' or
2349 `T::f' in the vtable for `R'.
2350
2351 The solution is to look at all paths to BINFO. If we find
2352 different overriders along any two, then there is a problem. */
2353 if (DECL_THUNK_P (fn))
2354 fn = THUNK_TARGET (fn);
2355
2356 /* Determine the depth of the hierarchy. */
2357 ffod.fn = fn;
2358 ffod.declaring_base = binfo;
2359 ffod.candidates = NULL_TREE;
2360 ffod.path.create (30);
2361
2362 dfs_walk_all (derived, dfs_find_final_overrider_pre,
2363 dfs_find_final_overrider_post, &ffod);
2364
2365 ffod.path.release ();
2366
2367 /* If there was no winner, issue an error message. */
2368 if (!ffod.candidates || TREE_CHAIN (ffod.candidates))
2369 return error_mark_node;
2370
2371 return ffod.candidates;
2372 }
2373
2374 /* Return the index of the vcall offset for FN when TYPE is used as a
2375 virtual base. */
2376
2377 static tree
get_vcall_index(tree fn,tree type)2378 get_vcall_index (tree fn, tree type)
2379 {
2380 vec<tree_pair_s, va_gc> *indices = CLASSTYPE_VCALL_INDICES (type);
2381 tree_pair_p p;
2382 unsigned ix;
2383
2384 FOR_EACH_VEC_SAFE_ELT (indices, ix, p)
2385 if ((DECL_DESTRUCTOR_P (fn) && DECL_DESTRUCTOR_P (p->purpose))
2386 || same_signature_p (fn, p->purpose))
2387 return p->value;
2388
2389 /* There should always be an appropriate index. */
2390 gcc_unreachable ();
2391 }
2392
2393 /* Update an entry in the vtable for BINFO, which is in the hierarchy
2394 dominated by T. FN is the old function; VIRTUALS points to the
2395 corresponding position in the new BINFO_VIRTUALS list. IX is the index
2396 of that entry in the list. */
2397
2398 static void
update_vtable_entry_for_fn(tree t,tree binfo,tree fn,tree * virtuals,unsigned ix)2399 update_vtable_entry_for_fn (tree t, tree binfo, tree fn, tree* virtuals,
2400 unsigned ix)
2401 {
2402 tree b;
2403 tree overrider;
2404 tree delta;
2405 tree virtual_base;
2406 tree first_defn;
2407 tree overrider_fn, overrider_target;
2408 tree target_fn = DECL_THUNK_P (fn) ? THUNK_TARGET (fn) : fn;
2409 tree over_return, base_return;
2410 bool lost = false;
2411
2412 /* Find the nearest primary base (possibly binfo itself) which defines
2413 this function; this is the class the caller will convert to when
2414 calling FN through BINFO. */
2415 for (b = binfo; ; b = get_primary_binfo (b))
2416 {
2417 gcc_assert (b);
2418 if (look_for_overrides_here (BINFO_TYPE (b), target_fn))
2419 break;
2420
2421 /* The nearest definition is from a lost primary. */
2422 if (BINFO_LOST_PRIMARY_P (b))
2423 lost = true;
2424 }
2425 first_defn = b;
2426
2427 /* Find the final overrider. */
2428 overrider = find_final_overrider (TYPE_BINFO (t), b, target_fn);
2429 if (overrider == error_mark_node)
2430 {
2431 error ("no unique final overrider for %qD in %qT", target_fn, t);
2432 return;
2433 }
2434 overrider_target = overrider_fn = TREE_PURPOSE (overrider);
2435
2436 /* Check for adjusting covariant return types. */
2437 over_return = TREE_TYPE (TREE_TYPE (overrider_target));
2438 base_return = TREE_TYPE (TREE_TYPE (target_fn));
2439
2440 if (INDIRECT_TYPE_P (over_return)
2441 && TREE_CODE (over_return) == TREE_CODE (base_return)
2442 && CLASS_TYPE_P (TREE_TYPE (over_return))
2443 && CLASS_TYPE_P (TREE_TYPE (base_return))
2444 /* If the overrider is invalid, don't even try. */
2445 && !DECL_INVALID_OVERRIDER_P (overrider_target))
2446 {
2447 /* If FN is a covariant thunk, we must figure out the adjustment
2448 to the final base FN was converting to. As OVERRIDER_TARGET might
2449 also be converting to the return type of FN, we have to
2450 combine the two conversions here. */
2451 tree fixed_offset, virtual_offset;
2452
2453 over_return = TREE_TYPE (over_return);
2454 base_return = TREE_TYPE (base_return);
2455
2456 if (DECL_THUNK_P (fn))
2457 {
2458 gcc_assert (DECL_RESULT_THUNK_P (fn));
2459 fixed_offset = ssize_int (THUNK_FIXED_OFFSET (fn));
2460 virtual_offset = THUNK_VIRTUAL_OFFSET (fn);
2461 }
2462 else
2463 fixed_offset = virtual_offset = NULL_TREE;
2464
2465 if (virtual_offset)
2466 /* Find the equivalent binfo within the return type of the
2467 overriding function. We will want the vbase offset from
2468 there. */
2469 virtual_offset = binfo_for_vbase (BINFO_TYPE (virtual_offset),
2470 over_return);
2471 else if (!same_type_ignoring_top_level_qualifiers_p
2472 (over_return, base_return))
2473 {
2474 /* There was no existing virtual thunk (which takes
2475 precedence). So find the binfo of the base function's
2476 return type within the overriding function's return type.
2477 Fortunately we know the covariancy is valid (it
2478 has already been checked), so we can just iterate along
2479 the binfos, which have been chained in inheritance graph
2480 order. Of course it is lame that we have to repeat the
2481 search here anyway -- we should really be caching pieces
2482 of the vtable and avoiding this repeated work. */
2483 tree thunk_binfo = NULL_TREE;
2484 tree base_binfo = TYPE_BINFO (base_return);
2485
2486 /* Find the base binfo within the overriding function's
2487 return type. We will always find a thunk_binfo, except
2488 when the covariancy is invalid (which we will have
2489 already diagnosed). */
2490 if (base_binfo)
2491 for (thunk_binfo = TYPE_BINFO (over_return); thunk_binfo;
2492 thunk_binfo = TREE_CHAIN (thunk_binfo))
2493 if (SAME_BINFO_TYPE_P (BINFO_TYPE (thunk_binfo),
2494 BINFO_TYPE (base_binfo)))
2495 break;
2496 gcc_assert (thunk_binfo || errorcount);
2497
2498 /* See if virtual inheritance is involved. */
2499 for (virtual_offset = thunk_binfo;
2500 virtual_offset;
2501 virtual_offset = BINFO_INHERITANCE_CHAIN (virtual_offset))
2502 if (BINFO_VIRTUAL_P (virtual_offset))
2503 break;
2504
2505 if (virtual_offset
2506 || (thunk_binfo && !BINFO_OFFSET_ZEROP (thunk_binfo)))
2507 {
2508 tree offset = fold_convert (ssizetype, BINFO_OFFSET (thunk_binfo));
2509
2510 if (virtual_offset)
2511 {
2512 /* We convert via virtual base. Adjust the fixed
2513 offset to be from there. */
2514 offset =
2515 size_diffop (offset,
2516 fold_convert (ssizetype,
2517 BINFO_OFFSET (virtual_offset)));
2518 }
2519 if (fixed_offset)
2520 /* There was an existing fixed offset, this must be
2521 from the base just converted to, and the base the
2522 FN was thunking to. */
2523 fixed_offset = size_binop (PLUS_EXPR, fixed_offset, offset);
2524 else
2525 fixed_offset = offset;
2526 }
2527 }
2528
2529 if (fixed_offset || virtual_offset)
2530 /* Replace the overriding function with a covariant thunk. We
2531 will emit the overriding function in its own slot as
2532 well. */
2533 overrider_fn = make_thunk (overrider_target, /*this_adjusting=*/0,
2534 fixed_offset, virtual_offset);
2535 }
2536 else
2537 gcc_assert (DECL_INVALID_OVERRIDER_P (overrider_target) ||
2538 !DECL_THUNK_P (fn));
2539
2540 /* If we need a covariant thunk, then we may need to adjust first_defn.
2541 The ABI specifies that the thunks emitted with a function are
2542 determined by which bases the function overrides, so we need to be
2543 sure that we're using a thunk for some overridden base; even if we
2544 know that the necessary this adjustment is zero, there may not be an
2545 appropriate zero-this-adjustment thunk for us to use since thunks for
2546 overriding virtual bases always use the vcall offset.
2547
2548 Furthermore, just choosing any base that overrides this function isn't
2549 quite right, as this slot won't be used for calls through a type that
2550 puts a covariant thunk here. Calling the function through such a type
2551 will use a different slot, and that slot is the one that determines
2552 the thunk emitted for that base.
2553
2554 So, keep looking until we find the base that we're really overriding
2555 in this slot: the nearest primary base that doesn't use a covariant
2556 thunk in this slot. */
2557 if (overrider_target != overrider_fn)
2558 {
2559 if (BINFO_TYPE (b) == DECL_CONTEXT (overrider_target))
2560 /* We already know that the overrider needs a covariant thunk. */
2561 b = get_primary_binfo (b);
2562 for (; ; b = get_primary_binfo (b))
2563 {
2564 tree main_binfo = TYPE_BINFO (BINFO_TYPE (b));
2565 tree bv = chain_index (ix, BINFO_VIRTUALS (main_binfo));
2566 if (!DECL_THUNK_P (TREE_VALUE (bv)))
2567 break;
2568 if (BINFO_LOST_PRIMARY_P (b))
2569 lost = true;
2570 }
2571 first_defn = b;
2572 }
2573
2574 /* Assume that we will produce a thunk that convert all the way to
2575 the final overrider, and not to an intermediate virtual base. */
2576 virtual_base = NULL_TREE;
2577
2578 /* See if we can convert to an intermediate virtual base first, and then
2579 use the vcall offset located there to finish the conversion. */
2580 for (; b; b = BINFO_INHERITANCE_CHAIN (b))
2581 {
2582 /* If we find the final overrider, then we can stop
2583 walking. */
2584 if (SAME_BINFO_TYPE_P (BINFO_TYPE (b),
2585 BINFO_TYPE (TREE_VALUE (overrider))))
2586 break;
2587
2588 /* If we find a virtual base, and we haven't yet found the
2589 overrider, then there is a virtual base between the
2590 declaring base (first_defn) and the final overrider. */
2591 if (BINFO_VIRTUAL_P (b))
2592 {
2593 virtual_base = b;
2594 break;
2595 }
2596 }
2597
2598 /* Compute the constant adjustment to the `this' pointer. The
2599 `this' pointer, when this function is called, will point at BINFO
2600 (or one of its primary bases, which are at the same offset). */
2601 if (virtual_base)
2602 /* The `this' pointer needs to be adjusted from the declaration to
2603 the nearest virtual base. */
2604 delta = size_diffop_loc (input_location,
2605 fold_convert (ssizetype, BINFO_OFFSET (virtual_base)),
2606 fold_convert (ssizetype, BINFO_OFFSET (first_defn)));
2607 else if (lost)
2608 /* If the nearest definition is in a lost primary, we don't need an
2609 entry in our vtable. Except possibly in a constructor vtable,
2610 if we happen to get our primary back. In that case, the offset
2611 will be zero, as it will be a primary base. */
2612 delta = size_zero_node;
2613 else
2614 /* The `this' pointer needs to be adjusted from pointing to
2615 BINFO to pointing at the base where the final overrider
2616 appears. */
2617 delta = size_diffop_loc (input_location,
2618 fold_convert (ssizetype,
2619 BINFO_OFFSET (TREE_VALUE (overrider))),
2620 fold_convert (ssizetype, BINFO_OFFSET (binfo)));
2621
2622 modify_vtable_entry (t, binfo, overrider_fn, delta, virtuals);
2623
2624 if (virtual_base)
2625 BV_VCALL_INDEX (*virtuals)
2626 = get_vcall_index (overrider_target, BINFO_TYPE (virtual_base));
2627 else
2628 BV_VCALL_INDEX (*virtuals) = NULL_TREE;
2629
2630 BV_LOST_PRIMARY (*virtuals) = lost;
2631 }
2632
2633 /* Called from modify_all_vtables via dfs_walk. */
2634
2635 static tree
dfs_modify_vtables(tree binfo,void * data)2636 dfs_modify_vtables (tree binfo, void* data)
2637 {
2638 tree t = (tree) data;
2639 tree virtuals;
2640 tree old_virtuals;
2641 unsigned ix;
2642
2643 if (!TYPE_CONTAINS_VPTR_P (BINFO_TYPE (binfo)))
2644 /* A base without a vtable needs no modification, and its bases
2645 are uninteresting. */
2646 return dfs_skip_bases;
2647
2648 if (SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), t)
2649 && !CLASSTYPE_HAS_PRIMARY_BASE_P (t))
2650 /* Don't do the primary vtable, if it's new. */
2651 return NULL_TREE;
2652
2653 if (BINFO_PRIMARY_P (binfo) && !BINFO_VIRTUAL_P (binfo))
2654 /* There's no need to modify the vtable for a non-virtual primary
2655 base; we're not going to use that vtable anyhow. We do still
2656 need to do this for virtual primary bases, as they could become
2657 non-primary in a construction vtable. */
2658 return NULL_TREE;
2659
2660 make_new_vtable (t, binfo);
2661
2662 /* Now, go through each of the virtual functions in the virtual
2663 function table for BINFO. Find the final overrider, and update
2664 the BINFO_VIRTUALS list appropriately. */
2665 for (ix = 0, virtuals = BINFO_VIRTUALS (binfo),
2666 old_virtuals = BINFO_VIRTUALS (TYPE_BINFO (BINFO_TYPE (binfo)));
2667 virtuals;
2668 ix++, virtuals = TREE_CHAIN (virtuals),
2669 old_virtuals = TREE_CHAIN (old_virtuals))
2670 update_vtable_entry_for_fn (t,
2671 binfo,
2672 BV_FN (old_virtuals),
2673 &virtuals, ix);
2674
2675 return NULL_TREE;
2676 }
2677
2678 /* Update all of the primary and secondary vtables for T. Create new
2679 vtables as required, and initialize their RTTI information. Each
2680 of the functions in VIRTUALS is declared in T and may override a
2681 virtual function from a base class; find and modify the appropriate
2682 entries to point to the overriding functions. Returns a list, in
2683 declaration order, of the virtual functions that are declared in T,
2684 but do not appear in the primary base class vtable, and which
2685 should therefore be appended to the end of the vtable for T. */
2686
2687 static tree
modify_all_vtables(tree t,tree virtuals)2688 modify_all_vtables (tree t, tree virtuals)
2689 {
2690 tree binfo = TYPE_BINFO (t);
2691 tree *fnsp;
2692
2693 /* Mangle the vtable name before entering dfs_walk (c++/51884). */
2694 if (TYPE_CONTAINS_VPTR_P (t))
2695 get_vtable_decl (t, false);
2696
2697 /* Update all of the vtables. */
2698 dfs_walk_once (binfo, dfs_modify_vtables, NULL, t);
2699
2700 /* Add virtual functions not already in our primary vtable. These
2701 will be both those introduced by this class, and those overridden
2702 from secondary bases. It does not include virtuals merely
2703 inherited from secondary bases. */
2704 for (fnsp = &virtuals; *fnsp; )
2705 {
2706 tree fn = TREE_VALUE (*fnsp);
2707
2708 if (!value_member (fn, BINFO_VIRTUALS (binfo))
2709 || DECL_VINDEX (fn) == error_mark_node)
2710 {
2711 /* We don't need to adjust the `this' pointer when
2712 calling this function. */
2713 BV_DELTA (*fnsp) = integer_zero_node;
2714 BV_VCALL_INDEX (*fnsp) = NULL_TREE;
2715
2716 /* This is a function not already in our vtable. Keep it. */
2717 fnsp = &TREE_CHAIN (*fnsp);
2718 }
2719 else
2720 /* We've already got an entry for this function. Skip it. */
2721 *fnsp = TREE_CHAIN (*fnsp);
2722 }
2723
2724 return virtuals;
2725 }
2726
2727 /* Get the base virtual function declarations in T that have the
2728 indicated NAME. */
2729
2730 static void
get_basefndecls(tree name,tree t,vec<tree> * base_fndecls)2731 get_basefndecls (tree name, tree t, vec<tree> *base_fndecls)
2732 {
2733 bool found_decls = false;
2734
2735 /* Find virtual functions in T with the indicated NAME. */
2736 for (ovl_iterator iter (get_class_binding (t, name)); iter; ++iter)
2737 {
2738 tree method = *iter;
2739
2740 if (TREE_CODE (method) == FUNCTION_DECL && DECL_VINDEX (method))
2741 {
2742 base_fndecls->safe_push (method);
2743 found_decls = true;
2744 }
2745 }
2746
2747 if (found_decls)
2748 return;
2749
2750 int n_baseclasses = BINFO_N_BASE_BINFOS (TYPE_BINFO (t));
2751 for (int i = 0; i < n_baseclasses; i++)
2752 {
2753 tree basetype = BINFO_TYPE (BINFO_BASE_BINFO (TYPE_BINFO (t), i));
2754 get_basefndecls (name, basetype, base_fndecls);
2755 }
2756 }
2757
2758 /* If this declaration supersedes the declaration of
2759 a method declared virtual in the base class, then
2760 mark this field as being virtual as well. */
2761
2762 void
check_for_override(tree decl,tree ctype)2763 check_for_override (tree decl, tree ctype)
2764 {
2765 bool overrides_found = false;
2766 if (TREE_CODE (decl) == TEMPLATE_DECL)
2767 /* In [temp.mem] we have:
2768
2769 A specialization of a member function template does not
2770 override a virtual function from a base class. */
2771 return;
2772 if ((DECL_DESTRUCTOR_P (decl)
2773 || IDENTIFIER_VIRTUAL_P (DECL_NAME (decl))
2774 || DECL_CONV_FN_P (decl))
2775 && look_for_overrides (ctype, decl)
2776 && !DECL_STATIC_FUNCTION_P (decl))
2777 /* Set DECL_VINDEX to a value that is neither an INTEGER_CST nor
2778 the error_mark_node so that we know it is an overriding
2779 function. */
2780 {
2781 DECL_VINDEX (decl) = decl;
2782 overrides_found = true;
2783 if (warn_override && !DECL_OVERRIDE_P (decl)
2784 && !DECL_DESTRUCTOR_P (decl))
2785 warning_at (DECL_SOURCE_LOCATION (decl), OPT_Wsuggest_override,
2786 "%qD can be marked override", decl);
2787 }
2788
2789 if (DECL_VIRTUAL_P (decl))
2790 {
2791 if (!DECL_VINDEX (decl))
2792 DECL_VINDEX (decl) = error_mark_node;
2793 IDENTIFIER_VIRTUAL_P (DECL_NAME (decl)) = 1;
2794 if (DECL_DESTRUCTOR_P (decl))
2795 TYPE_HAS_NONTRIVIAL_DESTRUCTOR (ctype) = true;
2796 }
2797 else if (DECL_FINAL_P (decl))
2798 error ("%q+#D marked %<final%>, but is not virtual", decl);
2799 if (DECL_OVERRIDE_P (decl) && !overrides_found)
2800 error ("%q+#D marked %<override%>, but does not override", decl);
2801 }
2802
2803 /* Warn about hidden virtual functions that are not overridden in t.
2804 We know that constructors and destructors don't apply. */
2805
2806 static void
warn_hidden(tree t)2807 warn_hidden (tree t)
2808 {
2809 if (vec<tree, va_gc> *member_vec = CLASSTYPE_MEMBER_VEC (t))
2810 for (unsigned ix = member_vec->length (); ix--;)
2811 {
2812 tree fns = (*member_vec)[ix];
2813
2814 if (!OVL_P (fns))
2815 continue;
2816
2817 tree name = OVL_NAME (fns);
2818 auto_vec<tree, 20> base_fndecls;
2819 tree base_binfo;
2820 tree binfo;
2821 unsigned j;
2822
2823 /* Iterate through all of the base classes looking for possibly
2824 hidden functions. */
2825 for (binfo = TYPE_BINFO (t), j = 0;
2826 BINFO_BASE_ITERATE (binfo, j, base_binfo); j++)
2827 {
2828 tree basetype = BINFO_TYPE (base_binfo);
2829 get_basefndecls (name, basetype, &base_fndecls);
2830 }
2831
2832 /* If there are no functions to hide, continue. */
2833 if (base_fndecls.is_empty ())
2834 continue;
2835
2836 /* Remove any overridden functions. */
2837 for (ovl_iterator iter (fns); iter; ++iter)
2838 {
2839 tree fndecl = *iter;
2840 if (TREE_CODE (fndecl) == FUNCTION_DECL
2841 && DECL_VINDEX (fndecl))
2842 {
2843 /* If the method from the base class has the same
2844 signature as the method from the derived class, it
2845 has been overridden. */
2846 for (size_t k = 0; k < base_fndecls.length (); k++)
2847 if (base_fndecls[k]
2848 && same_signature_p (fndecl, base_fndecls[k]))
2849 base_fndecls[k] = NULL_TREE;
2850 }
2851 }
2852
2853 /* Now give a warning for all base functions without overriders,
2854 as they are hidden. */
2855 tree base_fndecl;
2856 FOR_EACH_VEC_ELT (base_fndecls, j, base_fndecl)
2857 if (base_fndecl)
2858 {
2859 /* Here we know it is a hider, and no overrider exists. */
2860 warning_at (location_of (base_fndecl),
2861 OPT_Woverloaded_virtual,
2862 "%qD was hidden", base_fndecl);
2863 warning_at (location_of (fns),
2864 OPT_Woverloaded_virtual, " by %qD", fns);
2865 }
2866 }
2867 }
2868
2869 /* Recursive helper for finish_struct_anon. */
2870
2871 static void
finish_struct_anon_r(tree field,bool complain)2872 finish_struct_anon_r (tree field, bool complain)
2873 {
2874 for (tree elt = TYPE_FIELDS (TREE_TYPE (field)); elt; elt = DECL_CHAIN (elt))
2875 {
2876 /* We're generally only interested in entities the user
2877 declared, but we also find nested classes by noticing
2878 the TYPE_DECL that we create implicitly. You're
2879 allowed to put one anonymous union inside another,
2880 though, so we explicitly tolerate that. We use
2881 TYPE_UNNAMED_P rather than ANON_AGGR_TYPE_P so that
2882 we also allow unnamed types used for defining fields. */
2883 if (DECL_ARTIFICIAL (elt)
2884 && (!DECL_IMPLICIT_TYPEDEF_P (elt)
2885 || TYPE_UNNAMED_P (TREE_TYPE (elt))))
2886 continue;
2887
2888 if (complain
2889 && (TREE_CODE (elt) != FIELD_DECL
2890 || (TREE_PRIVATE (elt) || TREE_PROTECTED (elt))))
2891 {
2892 /* We already complained about static data members in
2893 finish_static_data_member_decl. */
2894 if (!VAR_P (elt))
2895 {
2896 auto_diagnostic_group d;
2897 if (permerror (DECL_SOURCE_LOCATION (elt),
2898 TREE_CODE (TREE_TYPE (field)) == UNION_TYPE
2899 ? "%q#D invalid; an anonymous union may "
2900 "only have public non-static data members"
2901 : "%q#D invalid; an anonymous struct may "
2902 "only have public non-static data members", elt))
2903 {
2904 static bool hint;
2905 if (flag_permissive && !hint)
2906 {
2907 hint = true;
2908 inform (DECL_SOURCE_LOCATION (elt),
2909 "this flexibility is deprecated and will be "
2910 "removed");
2911 }
2912 }
2913 }
2914 }
2915
2916 TREE_PRIVATE (elt) = TREE_PRIVATE (field);
2917 TREE_PROTECTED (elt) = TREE_PROTECTED (field);
2918
2919 /* Recurse into the anonymous aggregates to correctly handle
2920 access control (c++/24926):
2921
2922 class A {
2923 union {
2924 union {
2925 int i;
2926 };
2927 };
2928 };
2929
2930 int j=A().i; */
2931 if (DECL_NAME (elt) == NULL_TREE
2932 && ANON_AGGR_TYPE_P (TREE_TYPE (elt)))
2933 finish_struct_anon_r (elt, /*complain=*/false);
2934 }
2935 }
2936
2937 /* Check for things that are invalid. There are probably plenty of other
2938 things we should check for also. */
2939
2940 static void
finish_struct_anon(tree t)2941 finish_struct_anon (tree t)
2942 {
2943 for (tree field = TYPE_FIELDS (t); field; field = DECL_CHAIN (field))
2944 {
2945 if (TREE_STATIC (field))
2946 continue;
2947 if (TREE_CODE (field) != FIELD_DECL)
2948 continue;
2949
2950 if (DECL_NAME (field) == NULL_TREE
2951 && ANON_AGGR_TYPE_P (TREE_TYPE (field)))
2952 finish_struct_anon_r (field, /*complain=*/true);
2953 }
2954 }
2955
2956 /* Add T to CLASSTYPE_DECL_LIST of current_class_type which
2957 will be used later during class template instantiation.
2958 When FRIEND_P is zero, T can be a static member data (VAR_DECL),
2959 a non-static member data (FIELD_DECL), a member function
2960 (FUNCTION_DECL), a nested type (RECORD_TYPE, ENUM_TYPE),
2961 a typedef (TYPE_DECL) or a member class template (TEMPLATE_DECL)
2962 When FRIEND_P is nonzero, T is either a friend class
2963 (RECORD_TYPE, TEMPLATE_DECL) or a friend function
2964 (FUNCTION_DECL, TEMPLATE_DECL). */
2965
2966 void
maybe_add_class_template_decl_list(tree type,tree t,int friend_p)2967 maybe_add_class_template_decl_list (tree type, tree t, int friend_p)
2968 {
2969 /* Save some memory by not creating TREE_LIST if TYPE is not template. */
2970 if (CLASSTYPE_TEMPLATE_INFO (type))
2971 CLASSTYPE_DECL_LIST (type)
2972 = tree_cons (friend_p ? NULL_TREE : type,
2973 t, CLASSTYPE_DECL_LIST (type));
2974 }
2975
2976 /* This function is called from declare_virt_assop_and_dtor via
2977 dfs_walk_all.
2978
2979 DATA is a type that direcly or indirectly inherits the base
2980 represented by BINFO. If BINFO contains a virtual assignment [copy
2981 assignment or move assigment] operator or a virtual constructor,
2982 declare that function in DATA if it hasn't been already declared. */
2983
2984 static tree
dfs_declare_virt_assop_and_dtor(tree binfo,void * data)2985 dfs_declare_virt_assop_and_dtor (tree binfo, void *data)
2986 {
2987 tree bv, fn, t = (tree)data;
2988 tree opname = assign_op_identifier;
2989
2990 gcc_assert (t && CLASS_TYPE_P (t));
2991 gcc_assert (binfo && TREE_CODE (binfo) == TREE_BINFO);
2992
2993 if (!TYPE_CONTAINS_VPTR_P (BINFO_TYPE (binfo)))
2994 /* A base without a vtable needs no modification, and its bases
2995 are uninteresting. */
2996 return dfs_skip_bases;
2997
2998 if (BINFO_PRIMARY_P (binfo))
2999 /* If this is a primary base, then we have already looked at the
3000 virtual functions of its vtable. */
3001 return NULL_TREE;
3002
3003 for (bv = BINFO_VIRTUALS (binfo); bv; bv = TREE_CHAIN (bv))
3004 {
3005 fn = BV_FN (bv);
3006
3007 if (DECL_NAME (fn) == opname)
3008 {
3009 if (CLASSTYPE_LAZY_COPY_ASSIGN (t))
3010 lazily_declare_fn (sfk_copy_assignment, t);
3011 if (CLASSTYPE_LAZY_MOVE_ASSIGN (t))
3012 lazily_declare_fn (sfk_move_assignment, t);
3013 }
3014 else if (DECL_DESTRUCTOR_P (fn)
3015 && CLASSTYPE_LAZY_DESTRUCTOR (t))
3016 lazily_declare_fn (sfk_destructor, t);
3017 }
3018
3019 return NULL_TREE;
3020 }
3021
3022 /* If the class type T has a direct or indirect base that contains a
3023 virtual assignment operator or a virtual destructor, declare that
3024 function in T if it hasn't been already declared. */
3025
3026 static void
declare_virt_assop_and_dtor(tree t)3027 declare_virt_assop_and_dtor (tree t)
3028 {
3029 if (!(TYPE_POLYMORPHIC_P (t)
3030 && (CLASSTYPE_LAZY_COPY_ASSIGN (t)
3031 || CLASSTYPE_LAZY_MOVE_ASSIGN (t)
3032 || CLASSTYPE_LAZY_DESTRUCTOR (t))))
3033 return;
3034
3035 dfs_walk_all (TYPE_BINFO (t),
3036 dfs_declare_virt_assop_and_dtor,
3037 NULL, t);
3038 }
3039
3040 /* Declare the inheriting constructor for class T inherited from base
3041 constructor CTOR with the parameter array PARMS of size NPARMS. */
3042
3043 static void
one_inheriting_sig(tree t,tree ctor,tree * parms,int nparms)3044 one_inheriting_sig (tree t, tree ctor, tree *parms, int nparms)
3045 {
3046 gcc_assert (TYPE_MAIN_VARIANT (t) == t);
3047
3048 /* We don't declare an inheriting ctor that would be a default,
3049 copy or move ctor for derived or base. */
3050 if (nparms == 0)
3051 return;
3052 if (nparms == 1
3053 && TYPE_REF_P (parms[0]))
3054 {
3055 tree parm = TYPE_MAIN_VARIANT (TREE_TYPE (parms[0]));
3056 if (parm == t || parm == DECL_CONTEXT (ctor))
3057 return;
3058 }
3059
3060 tree parmlist = void_list_node;
3061 for (int i = nparms - 1; i >= 0; i--)
3062 parmlist = tree_cons (NULL_TREE, parms[i], parmlist);
3063 tree fn = implicitly_declare_fn (sfk_inheriting_constructor,
3064 t, false, ctor, parmlist);
3065
3066 if (add_method (t, fn, false))
3067 {
3068 DECL_CHAIN (fn) = TYPE_FIELDS (t);
3069 TYPE_FIELDS (t) = fn;
3070 }
3071 }
3072
3073 /* Declare all the inheriting constructors for class T inherited from base
3074 constructor CTOR. */
3075
3076 static void
one_inherited_ctor(tree ctor,tree t,tree using_decl)3077 one_inherited_ctor (tree ctor, tree t, tree using_decl)
3078 {
3079 tree parms = FUNCTION_FIRST_USER_PARMTYPE (ctor);
3080
3081 if (flag_new_inheriting_ctors)
3082 {
3083 ctor = implicitly_declare_fn (sfk_inheriting_constructor,
3084 t, /*const*/false, ctor, parms);
3085 add_method (t, ctor, using_decl != NULL_TREE);
3086 TYPE_HAS_USER_CONSTRUCTOR (t) = true;
3087 return;
3088 }
3089
3090 tree *new_parms = XALLOCAVEC (tree, list_length (parms));
3091 int i = 0;
3092 for (; parms && parms != void_list_node; parms = TREE_CHAIN (parms))
3093 {
3094 if (TREE_PURPOSE (parms))
3095 one_inheriting_sig (t, ctor, new_parms, i);
3096 new_parms[i++] = TREE_VALUE (parms);
3097 }
3098 one_inheriting_sig (t, ctor, new_parms, i);
3099 if (parms == NULL_TREE)
3100 {
3101 auto_diagnostic_group d;
3102 if (warning (OPT_Winherited_variadic_ctor,
3103 "the ellipsis in %qD is not inherited", ctor))
3104 inform (DECL_SOURCE_LOCATION (ctor), "%qD declared here", ctor);
3105 }
3106 }
3107
3108 /* Create default constructors, assignment operators, and so forth for
3109 the type indicated by T, if they are needed. CANT_HAVE_CONST_CTOR,
3110 and CANT_HAVE_CONST_ASSIGNMENT are nonzero if, for whatever reason,
3111 the class cannot have a default constructor, copy constructor
3112 taking a const reference argument, or an assignment operator taking
3113 a const reference, respectively. */
3114
3115 static void
add_implicitly_declared_members(tree t,tree * access_decls,int cant_have_const_cctor,int cant_have_const_assignment)3116 add_implicitly_declared_members (tree t, tree* access_decls,
3117 int cant_have_const_cctor,
3118 int cant_have_const_assignment)
3119 {
3120 /* Destructor. */
3121 if (!CLASSTYPE_DESTRUCTOR (t))
3122 /* In general, we create destructors lazily. */
3123 CLASSTYPE_LAZY_DESTRUCTOR (t) = 1;
3124
3125 bool move_ok = false;
3126 if (cxx_dialect >= cxx11 && CLASSTYPE_LAZY_DESTRUCTOR (t)
3127 && !TYPE_HAS_COPY_CTOR (t) && !TYPE_HAS_COPY_ASSIGN (t)
3128 && !classtype_has_move_assign_or_move_ctor_p (t, false))
3129 move_ok = true;
3130
3131 /* [class.ctor]
3132
3133 If there is no user-declared constructor for a class, a default
3134 constructor is implicitly declared. */
3135 if (! TYPE_HAS_USER_CONSTRUCTOR (t))
3136 {
3137 TYPE_HAS_DEFAULT_CONSTRUCTOR (t) = 1;
3138 CLASSTYPE_LAZY_DEFAULT_CTOR (t) = 1;
3139 if (cxx_dialect >= cxx11)
3140 TYPE_HAS_CONSTEXPR_CTOR (t)
3141 /* Don't force the declaration to get a hard answer; if the
3142 definition would have made the class non-literal, it will still be
3143 non-literal because of the base or member in question, and that
3144 gives a better diagnostic. */
3145 = type_maybe_constexpr_default_constructor (t);
3146 }
3147
3148 /* [class.ctor]
3149
3150 If a class definition does not explicitly declare a copy
3151 constructor, one is declared implicitly. */
3152 if (! TYPE_HAS_COPY_CTOR (t))
3153 {
3154 TYPE_HAS_COPY_CTOR (t) = 1;
3155 TYPE_HAS_CONST_COPY_CTOR (t) = !cant_have_const_cctor;
3156 CLASSTYPE_LAZY_COPY_CTOR (t) = 1;
3157 if (move_ok)
3158 CLASSTYPE_LAZY_MOVE_CTOR (t) = 1;
3159 }
3160
3161 /* If there is no assignment operator, one will be created if and
3162 when it is needed. For now, just record whether or not the type
3163 of the parameter to the assignment operator will be a const or
3164 non-const reference. */
3165 if (!TYPE_HAS_COPY_ASSIGN (t))
3166 {
3167 TYPE_HAS_COPY_ASSIGN (t) = 1;
3168 TYPE_HAS_CONST_COPY_ASSIGN (t) = !cant_have_const_assignment;
3169 CLASSTYPE_LAZY_COPY_ASSIGN (t) = 1;
3170 if (move_ok && !LAMBDA_TYPE_P (t))
3171 CLASSTYPE_LAZY_MOVE_ASSIGN (t) = 1;
3172 }
3173
3174 /* We can't be lazy about declaring functions that might override
3175 a virtual function from a base class. */
3176 declare_virt_assop_and_dtor (t);
3177
3178 while (*access_decls)
3179 {
3180 tree using_decl = TREE_VALUE (*access_decls);
3181 tree decl = USING_DECL_DECLS (using_decl);
3182 if (DECL_NAME (using_decl) == ctor_identifier)
3183 {
3184 /* declare, then remove the decl */
3185 tree ctor_list = decl;
3186 location_t loc = input_location;
3187 input_location = DECL_SOURCE_LOCATION (using_decl);
3188 for (ovl_iterator iter (ctor_list); iter; ++iter)
3189 one_inherited_ctor (*iter, t, using_decl);
3190 *access_decls = TREE_CHAIN (*access_decls);
3191 input_location = loc;
3192 }
3193 else
3194 access_decls = &TREE_CHAIN (*access_decls);
3195 }
3196 }
3197
3198 /* FIELD is a bit-field. We are finishing the processing for its
3199 enclosing type. Issue any appropriate messages and set appropriate
3200 flags. Returns false if an error has been diagnosed. */
3201
3202 static bool
check_bitfield_decl(tree field)3203 check_bitfield_decl (tree field)
3204 {
3205 tree type = TREE_TYPE (field);
3206 tree w;
3207
3208 /* Extract the declared width of the bitfield, which has been
3209 temporarily stashed in DECL_BIT_FIELD_REPRESENTATIVE by grokbitfield. */
3210 w = DECL_BIT_FIELD_REPRESENTATIVE (field);
3211 gcc_assert (w != NULL_TREE);
3212 /* Remove the bit-field width indicator so that the rest of the
3213 compiler does not treat that value as a qualifier. */
3214 DECL_BIT_FIELD_REPRESENTATIVE (field) = NULL_TREE;
3215
3216 /* Detect invalid bit-field type. */
3217 if (!INTEGRAL_OR_ENUMERATION_TYPE_P (type))
3218 {
3219 error_at (DECL_SOURCE_LOCATION (field),
3220 "bit-field %q#D with non-integral type %qT", field, type);
3221 w = error_mark_node;
3222 }
3223 else
3224 {
3225 location_t loc = input_location;
3226 /* Avoid the non_lvalue wrapper added by fold for PLUS_EXPRs. */
3227 STRIP_NOPS (w);
3228
3229 /* detect invalid field size. */
3230 input_location = DECL_SOURCE_LOCATION (field);
3231 w = cxx_constant_value (w);
3232 input_location = loc;
3233
3234 if (TREE_CODE (w) != INTEGER_CST)
3235 {
3236 error ("bit-field %q+D width not an integer constant", field);
3237 w = error_mark_node;
3238 }
3239 else if (tree_int_cst_sgn (w) < 0)
3240 {
3241 error ("negative width in bit-field %q+D", field);
3242 w = error_mark_node;
3243 }
3244 else if (integer_zerop (w) && DECL_NAME (field) != 0)
3245 {
3246 error ("zero width for bit-field %q+D", field);
3247 w = error_mark_node;
3248 }
3249 else if ((TREE_CODE (type) != ENUMERAL_TYPE
3250 && TREE_CODE (type) != BOOLEAN_TYPE
3251 && compare_tree_int (w, TYPE_PRECISION (type)) > 0)
3252 || ((TREE_CODE (type) == ENUMERAL_TYPE
3253 || TREE_CODE (type) == BOOLEAN_TYPE)
3254 && tree_int_cst_lt (TYPE_SIZE (type), w)))
3255 warning_at (DECL_SOURCE_LOCATION (field), 0,
3256 "width of %qD exceeds its type", field);
3257 else if (TREE_CODE (type) == ENUMERAL_TYPE)
3258 {
3259 int prec = TYPE_PRECISION (ENUM_UNDERLYING_TYPE (type));
3260 if (compare_tree_int (w, prec) < 0)
3261 warning_at (DECL_SOURCE_LOCATION (field), 0,
3262 "%qD is too small to hold all values of %q#T",
3263 field, type);
3264 }
3265 }
3266
3267 if (w != error_mark_node)
3268 {
3269 DECL_SIZE (field) = fold_convert (bitsizetype, w);
3270 DECL_BIT_FIELD (field) = 1;
3271 return true;
3272 }
3273 else
3274 {
3275 /* Non-bit-fields are aligned for their type. */
3276 DECL_BIT_FIELD (field) = 0;
3277 CLEAR_DECL_C_BIT_FIELD (field);
3278 return false;
3279 }
3280 }
3281
3282 /* FIELD is a non bit-field. We are finishing the processing for its
3283 enclosing type T. Issue any appropriate messages and set appropriate
3284 flags. */
3285
3286 static bool
check_field_decl(tree field,tree t,int * cant_have_const_ctor,int * no_const_asn_ref)3287 check_field_decl (tree field,
3288 tree t,
3289 int* cant_have_const_ctor,
3290 int* no_const_asn_ref)
3291 {
3292 tree type = strip_array_types (TREE_TYPE (field));
3293 bool any_default_members = false;
3294
3295 /* In C++98 an anonymous union cannot contain any fields which would change
3296 the settings of CANT_HAVE_CONST_CTOR and friends. */
3297 if (ANON_UNION_TYPE_P (type) && cxx_dialect < cxx11)
3298 ;
3299 /* And, we don't set TYPE_HAS_CONST_COPY_CTOR, etc., for anonymous
3300 structs. So, we recurse through their fields here. */
3301 else if (ANON_AGGR_TYPE_P (type))
3302 {
3303 for (tree fields = TYPE_FIELDS (type); fields;
3304 fields = DECL_CHAIN (fields))
3305 if (TREE_CODE (fields) == FIELD_DECL)
3306 any_default_members |= check_field_decl (fields, t,
3307 cant_have_const_ctor,
3308 no_const_asn_ref);
3309 }
3310 /* Check members with class type for constructors, destructors,
3311 etc. */
3312 else if (CLASS_TYPE_P (type))
3313 {
3314 /* Never let anything with uninheritable virtuals
3315 make it through without complaint. */
3316 abstract_virtuals_error (field, type);
3317
3318 if (TREE_CODE (t) == UNION_TYPE && cxx_dialect < cxx11)
3319 {
3320 static bool warned;
3321 int oldcount = errorcount;
3322 if (TYPE_NEEDS_CONSTRUCTING (type))
3323 error ("member %q+#D with constructor not allowed in union",
3324 field);
3325 if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type))
3326 error ("member %q+#D with destructor not allowed in union", field);
3327 if (TYPE_HAS_COMPLEX_COPY_ASSIGN (type))
3328 error ("member %q+#D with copy assignment operator not allowed in union",
3329 field);
3330 if (!warned && errorcount > oldcount)
3331 {
3332 inform (DECL_SOURCE_LOCATION (field), "unrestricted unions "
3333 "only available with %<-std=c++11%> or %<-std=gnu++11%>");
3334 warned = true;
3335 }
3336 }
3337 else
3338 {
3339 TYPE_NEEDS_CONSTRUCTING (t) |= TYPE_NEEDS_CONSTRUCTING (type);
3340 TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t)
3341 |= TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type);
3342 TYPE_HAS_COMPLEX_COPY_ASSIGN (t)
3343 |= (TYPE_HAS_COMPLEX_COPY_ASSIGN (type)
3344 || !TYPE_HAS_COPY_ASSIGN (type));
3345 TYPE_HAS_COMPLEX_COPY_CTOR (t) |= (TYPE_HAS_COMPLEX_COPY_CTOR (type)
3346 || !TYPE_HAS_COPY_CTOR (type));
3347 TYPE_HAS_COMPLEX_MOVE_ASSIGN (t) |= TYPE_HAS_COMPLEX_MOVE_ASSIGN (type);
3348 TYPE_HAS_COMPLEX_MOVE_CTOR (t) |= TYPE_HAS_COMPLEX_MOVE_CTOR (type);
3349 TYPE_HAS_COMPLEX_DFLT (t) |= (!TYPE_HAS_DEFAULT_CONSTRUCTOR (type)
3350 || TYPE_HAS_COMPLEX_DFLT (type));
3351 }
3352
3353 if (TYPE_HAS_COPY_CTOR (type)
3354 && !TYPE_HAS_CONST_COPY_CTOR (type))
3355 *cant_have_const_ctor = 1;
3356
3357 if (TYPE_HAS_COPY_ASSIGN (type)
3358 && !TYPE_HAS_CONST_COPY_ASSIGN (type))
3359 *no_const_asn_ref = 1;
3360 }
3361
3362 check_abi_tags (t, field);
3363
3364 if (DECL_INITIAL (field) != NULL_TREE)
3365 /* `build_class_init_list' does not recognize
3366 non-FIELD_DECLs. */
3367 any_default_members = true;
3368
3369 return any_default_members;
3370 }
3371
3372 /* Check the data members (both static and non-static), class-scoped
3373 typedefs, etc., appearing in the declaration of T. Issue
3374 appropriate diagnostics. Sets ACCESS_DECLS to a list (in
3375 declaration order) of access declarations; each TREE_VALUE in this
3376 list is a USING_DECL.
3377
3378 In addition, set the following flags:
3379
3380 EMPTY_P
3381 The class is empty, i.e., contains no non-static data members.
3382
3383 CANT_HAVE_CONST_CTOR_P
3384 This class cannot have an implicitly generated copy constructor
3385 taking a const reference.
3386
3387 CANT_HAVE_CONST_ASN_REF
3388 This class cannot have an implicitly generated assignment
3389 operator taking a const reference.
3390
3391 All of these flags should be initialized before calling this
3392 function.
3393
3394 Returns a pointer to the end of the TYPE_FIELDs chain; additional
3395 fields can be added by adding to this chain. */
3396
3397 static void
check_field_decls(tree t,tree * access_decls,int * cant_have_const_ctor_p,int * no_const_asn_ref_p)3398 check_field_decls (tree t, tree *access_decls,
3399 int *cant_have_const_ctor_p,
3400 int *no_const_asn_ref_p)
3401 {
3402 tree *field;
3403 tree *next;
3404 bool has_pointers;
3405 bool any_default_members;
3406 int cant_pack = 0;
3407 int field_access = -1;
3408
3409 /* Assume there are no access declarations. */
3410 *access_decls = NULL_TREE;
3411 /* Assume this class has no pointer members. */
3412 has_pointers = false;
3413 /* Assume none of the members of this class have default
3414 initializations. */
3415 any_default_members = false;
3416
3417 for (field = &TYPE_FIELDS (t); *field; field = next)
3418 {
3419 tree x = *field;
3420 tree type = TREE_TYPE (x);
3421 int this_field_access;
3422
3423 next = &DECL_CHAIN (x);
3424
3425 if (TREE_CODE (x) == USING_DECL)
3426 {
3427 /* Save the access declarations for our caller. */
3428 *access_decls = tree_cons (NULL_TREE, x, *access_decls);
3429 continue;
3430 }
3431
3432 if (TREE_CODE (x) == TYPE_DECL
3433 || TREE_CODE (x) == TEMPLATE_DECL)
3434 continue;
3435
3436 if (TREE_CODE (x) == FUNCTION_DECL)
3437 /* FIXME: We should fold in the checking from check_methods. */
3438 continue;
3439
3440 /* If we've gotten this far, it's a data member, possibly static,
3441 or an enumerator. */
3442 if (TREE_CODE (x) != CONST_DECL)
3443 DECL_CONTEXT (x) = t;
3444
3445 /* When this goes into scope, it will be a non-local reference. */
3446 DECL_NONLOCAL (x) = 1;
3447
3448 if (TREE_CODE (t) == UNION_TYPE)
3449 {
3450 /* [class.union] (C++98)
3451
3452 If a union contains a static data member, or a member of
3453 reference type, the program is ill-formed.
3454
3455 In C++11 [class.union] says:
3456 If a union contains a non-static data member of reference type
3457 the program is ill-formed. */
3458 if (VAR_P (x) && cxx_dialect < cxx11)
3459 {
3460 error ("in C++98 %q+D may not be static because it is "
3461 "a member of a union", x);
3462 continue;
3463 }
3464 if (TYPE_REF_P (type)
3465 && TREE_CODE (x) == FIELD_DECL)
3466 {
3467 error ("non-static data member %q+D in a union may not "
3468 "have reference type %qT", x, type);
3469 continue;
3470 }
3471 }
3472
3473 /* Perform error checking that did not get done in
3474 grokdeclarator. */
3475 if (TREE_CODE (type) == FUNCTION_TYPE)
3476 {
3477 error ("field %q+D invalidly declared function type", x);
3478 type = build_pointer_type (type);
3479 TREE_TYPE (x) = type;
3480 }
3481 else if (TREE_CODE (type) == METHOD_TYPE)
3482 {
3483 error ("field %q+D invalidly declared method type", x);
3484 type = build_pointer_type (type);
3485 TREE_TYPE (x) = type;
3486 }
3487
3488 if (type == error_mark_node)
3489 continue;
3490
3491 if (TREE_CODE (x) == CONST_DECL || VAR_P (x))
3492 continue;
3493
3494 /* Now it can only be a FIELD_DECL. */
3495
3496 if (TREE_PRIVATE (x) || TREE_PROTECTED (x))
3497 CLASSTYPE_NON_AGGREGATE (t) = 1;
3498
3499 /* If at least one non-static data member is non-literal, the whole
3500 class becomes non-literal. Per Core/1453, volatile non-static
3501 data members and base classes are also not allowed.
3502 Note: if the type is incomplete we will complain later on. */
3503 if (COMPLETE_TYPE_P (type)
3504 && (!literal_type_p (type) || CP_TYPE_VOLATILE_P (type)))
3505 CLASSTYPE_LITERAL_P (t) = false;
3506
3507 /* A standard-layout class is a class that:
3508 ...
3509 has the same access control (Clause 11) for all non-static data members,
3510 ... */
3511 this_field_access = TREE_PROTECTED (x) ? 1 : TREE_PRIVATE (x) ? 2 : 0;
3512 if (field_access == -1)
3513 field_access = this_field_access;
3514 else if (this_field_access != field_access)
3515 CLASSTYPE_NON_STD_LAYOUT (t) = 1;
3516
3517 /* If this is of reference type, check if it needs an init. */
3518 if (TYPE_REF_P (type))
3519 {
3520 CLASSTYPE_NON_LAYOUT_POD_P (t) = 1;
3521 CLASSTYPE_NON_STD_LAYOUT (t) = 1;
3522 if (DECL_INITIAL (x) == NULL_TREE)
3523 SET_CLASSTYPE_REF_FIELDS_NEED_INIT (t, 1);
3524 if (cxx_dialect < cxx11)
3525 {
3526 /* ARM $12.6.2: [A member initializer list] (or, for an
3527 aggregate, initialization by a brace-enclosed list) is the
3528 only way to initialize nonstatic const and reference
3529 members. */
3530 TYPE_HAS_COMPLEX_COPY_ASSIGN (t) = 1;
3531 TYPE_HAS_COMPLEX_MOVE_ASSIGN (t) = 1;
3532 }
3533 }
3534
3535 type = strip_array_types (type);
3536
3537 if (TYPE_PACKED (t))
3538 {
3539 if (!layout_pod_type_p (type) && !TYPE_PACKED (type))
3540 {
3541 warning_at
3542 (DECL_SOURCE_LOCATION (x), 0,
3543 "ignoring packed attribute because of unpacked non-POD field %q#D",
3544 x);
3545 cant_pack = 1;
3546 }
3547 else if (DECL_C_BIT_FIELD (x)
3548 || TYPE_ALIGN (TREE_TYPE (x)) > BITS_PER_UNIT)
3549 DECL_PACKED (x) = 1;
3550 }
3551
3552 if (DECL_C_BIT_FIELD (x)
3553 && integer_zerop (DECL_BIT_FIELD_REPRESENTATIVE (x)))
3554 /* We don't treat zero-width bitfields as making a class
3555 non-empty. */
3556 ;
3557 else if (field_poverlapping_p (x) && is_empty_class (type))
3558 {
3559 /* Empty data members also don't make a class non-empty. */
3560 CLASSTYPE_CONTAINS_EMPTY_CLASS_P (t) = 1;
3561 }
3562 else
3563 {
3564 /* The class is non-empty. */
3565 CLASSTYPE_EMPTY_P (t) = 0;
3566 /* The class is not even nearly empty. */
3567 CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
3568 /* If one of the data members contains an empty class,
3569 so does T. */
3570 if (CLASS_TYPE_P (type)
3571 && CLASSTYPE_CONTAINS_EMPTY_CLASS_P (type))
3572 CLASSTYPE_CONTAINS_EMPTY_CLASS_P (t) = 1;
3573 }
3574
3575 /* This is used by -Weffc++ (see below). Warn only for pointers
3576 to members which might hold dynamic memory. So do not warn
3577 for pointers to functions or pointers to members. */
3578 if (TYPE_PTR_P (type)
3579 && !TYPE_PTRFN_P (type))
3580 has_pointers = true;
3581
3582 if (CLASS_TYPE_P (type))
3583 {
3584 if (CLASSTYPE_REF_FIELDS_NEED_INIT (type))
3585 SET_CLASSTYPE_REF_FIELDS_NEED_INIT (t, 1);
3586 if (CLASSTYPE_READONLY_FIELDS_NEED_INIT (type))
3587 SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT (t, 1);
3588 }
3589
3590 if (DECL_MUTABLE_P (x) || TYPE_HAS_MUTABLE_P (type))
3591 CLASSTYPE_HAS_MUTABLE (t) = 1;
3592
3593 if (DECL_MUTABLE_P (x))
3594 {
3595 if (CP_TYPE_CONST_P (type))
3596 {
3597 error ("member %q+D cannot be declared both %<const%> "
3598 "and %<mutable%>", x);
3599 continue;
3600 }
3601 if (TYPE_REF_P (type))
3602 {
3603 error ("member %q+D cannot be declared as a %<mutable%> "
3604 "reference", x);
3605 continue;
3606 }
3607 }
3608
3609 if (! layout_pod_type_p (type))
3610 /* DR 148 now allows pointers to members (which are POD themselves),
3611 to be allowed in POD structs. */
3612 CLASSTYPE_NON_LAYOUT_POD_P (t) = 1;
3613
3614 if (field_poverlapping_p (x))
3615 /* A potentially-overlapping non-static data member makes the class
3616 non-layout-POD. */
3617 CLASSTYPE_NON_LAYOUT_POD_P (t) = 1;
3618
3619 if (!std_layout_type_p (type))
3620 CLASSTYPE_NON_STD_LAYOUT (t) = 1;
3621
3622 if (! zero_init_p (type))
3623 CLASSTYPE_NON_ZERO_INIT_P (t) = 1;
3624
3625 /* We set DECL_C_BIT_FIELD in grokbitfield.
3626 If the type and width are valid, we'll also set DECL_BIT_FIELD. */
3627 if (DECL_C_BIT_FIELD (x))
3628 check_bitfield_decl (x);
3629
3630 if (check_field_decl (x, t, cant_have_const_ctor_p, no_const_asn_ref_p))
3631 {
3632 if (any_default_members
3633 && TREE_CODE (t) == UNION_TYPE)
3634 error ("multiple fields in union %qT initialized", t);
3635 any_default_members = true;
3636 }
3637
3638 /* Now that we've removed bit-field widths from DECL_INITIAL,
3639 anything left in DECL_INITIAL is an NSDMI that makes the class
3640 non-aggregate in C++11. */
3641 if (DECL_INITIAL (x) && cxx_dialect < cxx14)
3642 CLASSTYPE_NON_AGGREGATE (t) = true;
3643
3644 /* If any field is const, the structure type is pseudo-const. */
3645 if (CP_TYPE_CONST_P (type))
3646 {
3647 C_TYPE_FIELDS_READONLY (t) = 1;
3648 if (DECL_INITIAL (x) == NULL_TREE)
3649 SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT (t, 1);
3650 if (cxx_dialect < cxx11)
3651 {
3652 /* ARM $12.6.2: [A member initializer list] (or, for an
3653 aggregate, initialization by a brace-enclosed list) is the
3654 only way to initialize nonstatic const and reference
3655 members. */
3656 TYPE_HAS_COMPLEX_COPY_ASSIGN (t) = 1;
3657 TYPE_HAS_COMPLEX_MOVE_ASSIGN (t) = 1;
3658 }
3659 }
3660 /* A field that is pseudo-const makes the structure likewise. */
3661 else if (CLASS_TYPE_P (type))
3662 {
3663 C_TYPE_FIELDS_READONLY (t) |= C_TYPE_FIELDS_READONLY (type);
3664 SET_CLASSTYPE_READONLY_FIELDS_NEED_INIT (t,
3665 CLASSTYPE_READONLY_FIELDS_NEED_INIT (t)
3666 | CLASSTYPE_READONLY_FIELDS_NEED_INIT (type));
3667 }
3668
3669 /* Core issue 80: A nonstatic data member is required to have a
3670 different name from the class iff the class has a
3671 user-declared constructor. */
3672 if (constructor_name_p (DECL_NAME (x), t)
3673 && TYPE_HAS_USER_CONSTRUCTOR (t))
3674 permerror (DECL_SOURCE_LOCATION (x),
3675 "field %q#D with same name as class", x);
3676 }
3677
3678 /* Effective C++ rule 11: if a class has dynamic memory held by pointers,
3679 it should also define a copy constructor and an assignment operator to
3680 implement the correct copy semantic (deep vs shallow, etc.). As it is
3681 not feasible to check whether the constructors do allocate dynamic memory
3682 and store it within members, we approximate the warning like this:
3683
3684 -- Warn only if there are members which are pointers
3685 -- Warn only if there is a non-trivial constructor (otherwise,
3686 there cannot be memory allocated).
3687 -- Warn only if there is a non-trivial destructor. We assume that the
3688 user at least implemented the cleanup correctly, and a destructor
3689 is needed to free dynamic memory.
3690
3691 This seems enough for practical purposes. */
3692 if (warn_ecpp
3693 && has_pointers
3694 && TYPE_HAS_USER_CONSTRUCTOR (t)
3695 && TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t)
3696 && !(TYPE_HAS_COPY_CTOR (t) && TYPE_HAS_COPY_ASSIGN (t)))
3697 {
3698 warning (OPT_Weffc__, "%q#T has pointer data members", t);
3699
3700 if (! TYPE_HAS_COPY_CTOR (t))
3701 {
3702 warning (OPT_Weffc__,
3703 " but does not override %<%T(const %T&)%>", t, t);
3704 if (!TYPE_HAS_COPY_ASSIGN (t))
3705 warning (OPT_Weffc__, " or %<operator=(const %T&)%>", t);
3706 }
3707 else if (! TYPE_HAS_COPY_ASSIGN (t))
3708 warning (OPT_Weffc__,
3709 " but does not override %<operator=(const %T&)%>", t);
3710 }
3711
3712 /* Non-static data member initializers make the default constructor
3713 non-trivial. */
3714 if (any_default_members)
3715 {
3716 TYPE_NEEDS_CONSTRUCTING (t) = true;
3717 TYPE_HAS_COMPLEX_DFLT (t) = true;
3718 }
3719
3720 /* If any of the fields couldn't be packed, unset TYPE_PACKED. */
3721 if (cant_pack)
3722 TYPE_PACKED (t) = 0;
3723
3724 /* Check anonymous struct/anonymous union fields. */
3725 finish_struct_anon (t);
3726
3727 /* We've built up the list of access declarations in reverse order.
3728 Fix that now. */
3729 *access_decls = nreverse (*access_decls);
3730 }
3731
3732 /* If TYPE is an empty class type, records its OFFSET in the table of
3733 OFFSETS. */
3734
3735 static int
record_subobject_offset(tree type,tree offset,splay_tree offsets)3736 record_subobject_offset (tree type, tree offset, splay_tree offsets)
3737 {
3738 splay_tree_node n;
3739
3740 if (!is_empty_class (type))
3741 return 0;
3742
3743 /* Record the location of this empty object in OFFSETS. */
3744 n = splay_tree_lookup (offsets, (splay_tree_key) offset);
3745 if (!n)
3746 n = splay_tree_insert (offsets,
3747 (splay_tree_key) offset,
3748 (splay_tree_value) NULL_TREE);
3749 n->value = ((splay_tree_value)
3750 tree_cons (NULL_TREE,
3751 type,
3752 (tree) n->value));
3753
3754 return 0;
3755 }
3756
3757 /* Returns nonzero if TYPE is an empty class type and there is
3758 already an entry in OFFSETS for the same TYPE as the same OFFSET. */
3759
3760 static int
check_subobject_offset(tree type,tree offset,splay_tree offsets)3761 check_subobject_offset (tree type, tree offset, splay_tree offsets)
3762 {
3763 splay_tree_node n;
3764 tree t;
3765
3766 if (!is_empty_class (type))
3767 return 0;
3768
3769 /* Record the location of this empty object in OFFSETS. */
3770 n = splay_tree_lookup (offsets, (splay_tree_key) offset);
3771 if (!n)
3772 return 0;
3773
3774 for (t = (tree) n->value; t; t = TREE_CHAIN (t))
3775 if (same_type_p (TREE_VALUE (t), type))
3776 return 1;
3777
3778 return 0;
3779 }
3780
3781 /* Walk through all the subobjects of TYPE (located at OFFSET). Call
3782 F for every subobject, passing it the type, offset, and table of
3783 OFFSETS. If VBASES_P is one, then virtual non-primary bases should
3784 be traversed.
3785
3786 If MAX_OFFSET is non-NULL, then subobjects with an offset greater
3787 than MAX_OFFSET will not be walked.
3788
3789 If F returns a nonzero value, the traversal ceases, and that value
3790 is returned. Otherwise, returns zero. */
3791
3792 static int
walk_subobject_offsets(tree type,subobject_offset_fn f,tree offset,splay_tree offsets,tree max_offset,int vbases_p)3793 walk_subobject_offsets (tree type,
3794 subobject_offset_fn f,
3795 tree offset,
3796 splay_tree offsets,
3797 tree max_offset,
3798 int vbases_p)
3799 {
3800 int r = 0;
3801 tree type_binfo = NULL_TREE;
3802
3803 /* If this OFFSET is bigger than the MAX_OFFSET, then we should
3804 stop. */
3805 if (max_offset && tree_int_cst_lt (max_offset, offset))
3806 return 0;
3807
3808 if (type == error_mark_node)
3809 return 0;
3810
3811 if (!TYPE_P (type))
3812 {
3813 type_binfo = type;
3814 type = BINFO_TYPE (type);
3815 }
3816
3817 if (CLASS_TYPE_P (type))
3818 {
3819 tree field;
3820 tree binfo;
3821 int i;
3822
3823 /* Avoid recursing into objects that are not interesting. */
3824 if (!CLASSTYPE_CONTAINS_EMPTY_CLASS_P (type))
3825 return 0;
3826
3827 /* Record the location of TYPE. */
3828 r = (*f) (type, offset, offsets);
3829 if (r)
3830 return r;
3831
3832 /* Iterate through the direct base classes of TYPE. */
3833 if (!type_binfo)
3834 type_binfo = TYPE_BINFO (type);
3835 for (i = 0; BINFO_BASE_ITERATE (type_binfo, i, binfo); i++)
3836 {
3837 tree binfo_offset;
3838
3839 if (BINFO_VIRTUAL_P (binfo))
3840 continue;
3841
3842 tree orig_binfo;
3843 /* We cannot rely on BINFO_OFFSET being set for the base
3844 class yet, but the offsets for direct non-virtual
3845 bases can be calculated by going back to the TYPE. */
3846 orig_binfo = BINFO_BASE_BINFO (TYPE_BINFO (type), i);
3847 binfo_offset = size_binop (PLUS_EXPR,
3848 offset,
3849 BINFO_OFFSET (orig_binfo));
3850
3851 r = walk_subobject_offsets (binfo,
3852 f,
3853 binfo_offset,
3854 offsets,
3855 max_offset,
3856 /*vbases_p=*/0);
3857 if (r)
3858 return r;
3859 }
3860
3861 if (CLASSTYPE_VBASECLASSES (type))
3862 {
3863 unsigned ix;
3864 vec<tree, va_gc> *vbases;
3865
3866 /* Iterate through the virtual base classes of TYPE. In G++
3867 3.2, we included virtual bases in the direct base class
3868 loop above, which results in incorrect results; the
3869 correct offsets for virtual bases are only known when
3870 working with the most derived type. */
3871 if (vbases_p)
3872 for (vbases = CLASSTYPE_VBASECLASSES (type), ix = 0;
3873 vec_safe_iterate (vbases, ix, &binfo); ix++)
3874 {
3875 r = walk_subobject_offsets (binfo,
3876 f,
3877 size_binop (PLUS_EXPR,
3878 offset,
3879 BINFO_OFFSET (binfo)),
3880 offsets,
3881 max_offset,
3882 /*vbases_p=*/0);
3883 if (r)
3884 return r;
3885 }
3886 else
3887 {
3888 /* We still have to walk the primary base, if it is
3889 virtual. (If it is non-virtual, then it was walked
3890 above.) */
3891 tree vbase = get_primary_binfo (type_binfo);
3892
3893 if (vbase && BINFO_VIRTUAL_P (vbase)
3894 && BINFO_PRIMARY_P (vbase)
3895 && BINFO_INHERITANCE_CHAIN (vbase) == type_binfo)
3896 {
3897 r = (walk_subobject_offsets
3898 (vbase, f, offset,
3899 offsets, max_offset, /*vbases_p=*/0));
3900 if (r)
3901 return r;
3902 }
3903 }
3904 }
3905
3906 /* Iterate through the fields of TYPE. */
3907 for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
3908 if (TREE_CODE (field) == FIELD_DECL
3909 && TREE_TYPE (field) != error_mark_node
3910 && !DECL_ARTIFICIAL (field))
3911 {
3912 tree field_offset;
3913
3914 field_offset = byte_position (field);
3915
3916 r = walk_subobject_offsets (TREE_TYPE (field),
3917 f,
3918 size_binop (PLUS_EXPR,
3919 offset,
3920 field_offset),
3921 offsets,
3922 max_offset,
3923 /*vbases_p=*/1);
3924 if (r)
3925 return r;
3926 }
3927 }
3928 else if (TREE_CODE (type) == ARRAY_TYPE)
3929 {
3930 tree element_type = strip_array_types (type);
3931 tree domain = TYPE_DOMAIN (type);
3932 tree index;
3933
3934 /* Avoid recursing into objects that are not interesting. */
3935 if (!CLASS_TYPE_P (element_type)
3936 || !CLASSTYPE_CONTAINS_EMPTY_CLASS_P (element_type)
3937 || !domain
3938 || integer_minus_onep (TYPE_MAX_VALUE (domain)))
3939 return 0;
3940
3941 /* Step through each of the elements in the array. */
3942 for (index = size_zero_node;
3943 !tree_int_cst_lt (TYPE_MAX_VALUE (domain), index);
3944 index = size_binop (PLUS_EXPR, index, size_one_node))
3945 {
3946 r = walk_subobject_offsets (TREE_TYPE (type),
3947 f,
3948 offset,
3949 offsets,
3950 max_offset,
3951 /*vbases_p=*/1);
3952 if (r)
3953 return r;
3954 offset = size_binop (PLUS_EXPR, offset,
3955 TYPE_SIZE_UNIT (TREE_TYPE (type)));
3956 /* If this new OFFSET is bigger than the MAX_OFFSET, then
3957 there's no point in iterating through the remaining
3958 elements of the array. */
3959 if (max_offset && tree_int_cst_lt (max_offset, offset))
3960 break;
3961 }
3962 }
3963
3964 return 0;
3965 }
3966
3967 /* Return true iff FIELD_DECL DECL is potentially overlapping. */
3968
3969 static bool
field_poverlapping_p(tree decl)3970 field_poverlapping_p (tree decl)
3971 {
3972 /* Base fields are actually potentially overlapping, but C++ bases go through
3973 a different code path based on binfos, and ObjC++ base fields are laid out
3974 in objc-act, so we don't want layout_class_type to mess with them. */
3975 if (DECL_FIELD_IS_BASE (decl))
3976 {
3977 gcc_checking_assert (c_dialect_objc ());
3978 return false;
3979 }
3980
3981 return lookup_attribute ("no_unique_address",
3982 DECL_ATTRIBUTES (decl));
3983 }
3984
3985 /* Record all of the empty subobjects of DECL_OR_BINFO. */
3986
3987 static void
record_subobject_offsets(tree decl_or_binfo,splay_tree offsets)3988 record_subobject_offsets (tree decl_or_binfo,
3989 splay_tree offsets)
3990 {
3991 tree type, offset;
3992 bool overlapping, vbases_p;
3993
3994 if (DECL_P (decl_or_binfo))
3995 {
3996 tree decl = decl_or_binfo;
3997 type = TREE_TYPE (decl);
3998 offset = byte_position (decl);
3999 overlapping = field_poverlapping_p (decl);
4000 vbases_p = true;
4001 }
4002 else
4003 {
4004 type = BINFO_TYPE (decl_or_binfo);
4005 offset = BINFO_OFFSET (decl_or_binfo);
4006 overlapping = true;
4007 vbases_p = false;
4008 }
4009
4010 tree max_offset;
4011 /* If recording subobjects for a non-static data member or a
4012 non-empty base class, we do not need to record offsets beyond
4013 the size of the biggest empty class. Additional data members
4014 will go at the end of the class. Additional base classes will go
4015 either at offset zero (if empty, in which case they cannot
4016 overlap with offsets past the size of the biggest empty class) or
4017 at the end of the class.
4018
4019 However, if we are placing an empty base class, then we must record
4020 all offsets, as either the empty class is at offset zero (where
4021 other empty classes might later be placed) or at the end of the
4022 class (where other objects might then be placed, so other empty
4023 subobjects might later overlap). */
4024 if (!overlapping
4025 || !is_empty_class (type))
4026 max_offset = sizeof_biggest_empty_class;
4027 else
4028 max_offset = NULL_TREE;
4029 walk_subobject_offsets (type, record_subobject_offset, offset,
4030 offsets, max_offset, vbases_p);
4031 }
4032
4033 /* Returns nonzero if any of the empty subobjects of TYPE (located at
4034 OFFSET) conflict with entries in OFFSETS. If VBASES_P is nonzero,
4035 virtual bases of TYPE are examined. */
4036
4037 static int
layout_conflict_p(tree type,tree offset,splay_tree offsets,int vbases_p)4038 layout_conflict_p (tree type,
4039 tree offset,
4040 splay_tree offsets,
4041 int vbases_p)
4042 {
4043 splay_tree_node max_node;
4044
4045 /* Get the node in OFFSETS that indicates the maximum offset where
4046 an empty subobject is located. */
4047 max_node = splay_tree_max (offsets);
4048 /* If there aren't any empty subobjects, then there's no point in
4049 performing this check. */
4050 if (!max_node)
4051 return 0;
4052
4053 return walk_subobject_offsets (type, check_subobject_offset, offset,
4054 offsets, (tree) (max_node->key),
4055 vbases_p);
4056 }
4057
4058 /* DECL is a FIELD_DECL corresponding either to a base subobject of a
4059 non-static data member of the type indicated by RLI. BINFO is the
4060 binfo corresponding to the base subobject, OFFSETS maps offsets to
4061 types already located at those offsets. This function determines
4062 the position of the DECL. */
4063
4064 static void
layout_nonempty_base_or_field(record_layout_info rli,tree decl,tree binfo,splay_tree offsets)4065 layout_nonempty_base_or_field (record_layout_info rli,
4066 tree decl,
4067 tree binfo,
4068 splay_tree offsets)
4069 {
4070 tree offset = NULL_TREE;
4071 bool field_p;
4072 tree type;
4073
4074 if (binfo)
4075 {
4076 /* For the purposes of determining layout conflicts, we want to
4077 use the class type of BINFO; TREE_TYPE (DECL) will be the
4078 CLASSTYPE_AS_BASE version, which does not contain entries for
4079 zero-sized bases. */
4080 type = TREE_TYPE (binfo);
4081 field_p = false;
4082 }
4083 else
4084 {
4085 type = TREE_TYPE (decl);
4086 field_p = true;
4087 }
4088
4089 /* Try to place the field. It may take more than one try if we have
4090 a hard time placing the field without putting two objects of the
4091 same type at the same address. */
4092 while (1)
4093 {
4094 struct record_layout_info_s old_rli = *rli;
4095
4096 /* Place this field. */
4097 place_field (rli, decl);
4098 offset = byte_position (decl);
4099
4100 /* We have to check to see whether or not there is already
4101 something of the same type at the offset we're about to use.
4102 For example, consider:
4103
4104 struct S {};
4105 struct T : public S { int i; };
4106 struct U : public S, public T {};
4107
4108 Here, we put S at offset zero in U. Then, we can't put T at
4109 offset zero -- its S component would be at the same address
4110 as the S we already allocated. So, we have to skip ahead.
4111 Since all data members, including those whose type is an
4112 empty class, have nonzero size, any overlap can happen only
4113 with a direct or indirect base-class -- it can't happen with
4114 a data member. */
4115 /* In a union, overlap is permitted; all members are placed at
4116 offset zero. */
4117 if (TREE_CODE (rli->t) == UNION_TYPE)
4118 break;
4119 if (layout_conflict_p (field_p ? type : binfo, offset,
4120 offsets, field_p))
4121 {
4122 /* Strip off the size allocated to this field. That puts us
4123 at the first place we could have put the field with
4124 proper alignment. */
4125 *rli = old_rli;
4126
4127 /* Bump up by the alignment required for the type. */
4128 rli->bitpos
4129 = size_binop (PLUS_EXPR, rli->bitpos,
4130 bitsize_int (binfo
4131 ? CLASSTYPE_ALIGN (type)
4132 : TYPE_ALIGN (type)));
4133 normalize_rli (rli);
4134 }
4135 else if (TREE_CODE (type) == NULLPTR_TYPE
4136 && warn_abi && abi_version_crosses (9))
4137 {
4138 /* Before ABI v9, we were giving nullptr_t alignment of 1; if
4139 the offset wasn't aligned like a pointer when we started to
4140 layout this field, that affects its position. */
4141 tree pos = rli_size_unit_so_far (&old_rli);
4142 if (int_cst_value (pos) % TYPE_ALIGN_UNIT (ptr_type_node) != 0)
4143 {
4144 if (abi_version_at_least (9))
4145 warning_at (DECL_SOURCE_LOCATION (decl), OPT_Wabi,
4146 "alignment of %qD increased in %<-fabi-version=9%> "
4147 "(GCC 5.2)", decl);
4148 else
4149 warning_at (DECL_SOURCE_LOCATION (decl), OPT_Wabi, "alignment "
4150 "of %qD will increase in %<-fabi-version=9%>",
4151 decl);
4152 }
4153 break;
4154 }
4155 else
4156 /* There was no conflict. We're done laying out this field. */
4157 break;
4158 }
4159
4160 /* Now that we know where it will be placed, update its
4161 BINFO_OFFSET. */
4162 if (binfo && CLASS_TYPE_P (BINFO_TYPE (binfo)))
4163 /* Indirect virtual bases may have a nonzero BINFO_OFFSET at
4164 this point because their BINFO_OFFSET is copied from another
4165 hierarchy. Therefore, we may not need to add the entire
4166 OFFSET. */
4167 propagate_binfo_offsets (binfo,
4168 size_diffop_loc (input_location,
4169 fold_convert (ssizetype, offset),
4170 fold_convert (ssizetype,
4171 BINFO_OFFSET (binfo))));
4172 }
4173
4174 /* Returns true if TYPE is empty and OFFSET is nonzero. */
4175
4176 static int
empty_base_at_nonzero_offset_p(tree type,tree offset,splay_tree)4177 empty_base_at_nonzero_offset_p (tree type,
4178 tree offset,
4179 splay_tree /*offsets*/)
4180 {
4181 return is_empty_class (type) && !integer_zerop (offset);
4182 }
4183
4184 /* Layout the empty base BINFO. EOC indicates the byte currently just
4185 past the end of the class, and should be correctly aligned for a
4186 class of the type indicated by BINFO; OFFSETS gives the offsets of
4187 the empty bases allocated so far. T is the most derived
4188 type. Return nonzero iff we added it at the end. */
4189
4190 static bool
layout_empty_base_or_field(record_layout_info rli,tree binfo_or_decl,splay_tree offsets)4191 layout_empty_base_or_field (record_layout_info rli, tree binfo_or_decl,
4192 splay_tree offsets)
4193 {
4194 tree alignment;
4195 bool atend = false;
4196 tree binfo = NULL_TREE;
4197 tree decl = NULL_TREE;
4198 tree type;
4199 if (TREE_CODE (binfo_or_decl) == TREE_BINFO)
4200 {
4201 binfo = binfo_or_decl;
4202 type = BINFO_TYPE (binfo);
4203 }
4204 else
4205 {
4206 decl = binfo_or_decl;
4207 type = TREE_TYPE (decl);
4208 }
4209
4210 /* On some platforms (ARM), even empty classes will not be
4211 byte-aligned. */
4212 tree eoc = round_up_loc (input_location,
4213 rli_size_unit_so_far (rli),
4214 CLASSTYPE_ALIGN_UNIT (type));
4215
4216 /* This routine should only be used for empty classes. */
4217 gcc_assert (is_empty_class (type));
4218 alignment = size_int (CLASSTYPE_ALIGN_UNIT (type));
4219
4220 /* This is an empty base class. We first try to put it at offset
4221 zero. */
4222 tree offset = size_zero_node;
4223 if (layout_conflict_p (type,
4224 offset,
4225 offsets,
4226 /*vbases_p=*/0))
4227 {
4228 /* That didn't work. Now, we move forward from the next
4229 available spot in the class. */
4230 atend = true;
4231 offset = eoc;
4232 while (1)
4233 {
4234 if (!layout_conflict_p (type,
4235 offset,
4236 offsets,
4237 /*vbases_p=*/0))
4238 /* We finally found a spot where there's no overlap. */
4239 break;
4240
4241 /* There's overlap here, too. Bump along to the next spot. */
4242 offset = size_binop (PLUS_EXPR, offset, alignment);
4243 }
4244 }
4245
4246 if (CLASSTYPE_USER_ALIGN (type))
4247 {
4248 rli->record_align = MAX (rli->record_align, CLASSTYPE_ALIGN (type));
4249 if (warn_packed)
4250 rli->unpacked_align = MAX (rli->unpacked_align, CLASSTYPE_ALIGN (type));
4251 TYPE_USER_ALIGN (rli->t) = 1;
4252 }
4253
4254 if (binfo)
4255 /* Adjust BINFO_OFFSET (binfo) to be exactly OFFSET. */
4256 propagate_binfo_offsets (binfo,
4257 size_diffop (offset, BINFO_OFFSET (binfo)));
4258 else
4259 {
4260 DECL_FIELD_OFFSET (decl) = offset;
4261 DECL_FIELD_BIT_OFFSET (decl) = bitsize_zero_node;
4262 SET_DECL_OFFSET_ALIGN (decl, BITS_PER_UNIT);
4263 }
4264
4265 return atend;
4266 }
4267
4268 /* Build the FIELD_DECL for BASETYPE as a base of T, add it to the chain of
4269 fields at NEXT_FIELD, and return it. */
4270
4271 static tree
build_base_field_1(tree t,tree basetype,tree * & next_field)4272 build_base_field_1 (tree t, tree basetype, tree *&next_field)
4273 {
4274 /* Create the FIELD_DECL. */
4275 gcc_assert (CLASSTYPE_AS_BASE (basetype));
4276 tree decl = build_decl (input_location,
4277 FIELD_DECL, NULL_TREE, CLASSTYPE_AS_BASE (basetype));
4278 DECL_ARTIFICIAL (decl) = 1;
4279 DECL_IGNORED_P (decl) = 1;
4280 DECL_FIELD_CONTEXT (decl) = t;
4281 if (is_empty_class (basetype))
4282 /* CLASSTYPE_SIZE is one byte, but the field needs to have size zero. */
4283 DECL_SIZE (decl) = DECL_SIZE_UNIT (decl) = size_zero_node;
4284 else
4285 {
4286 DECL_SIZE (decl) = CLASSTYPE_SIZE (basetype);
4287 DECL_SIZE_UNIT (decl) = CLASSTYPE_SIZE_UNIT (basetype);
4288 }
4289 SET_DECL_ALIGN (decl, CLASSTYPE_ALIGN (basetype));
4290 DECL_USER_ALIGN (decl) = CLASSTYPE_USER_ALIGN (basetype);
4291 SET_DECL_MODE (decl, TYPE_MODE (basetype));
4292 DECL_FIELD_IS_BASE (decl) = 1;
4293
4294 /* Add the new FIELD_DECL to the list of fields for T. */
4295 DECL_CHAIN (decl) = *next_field;
4296 *next_field = decl;
4297 next_field = &DECL_CHAIN (decl);
4298
4299 return decl;
4300 }
4301
4302 /* Layout the base given by BINFO in the class indicated by RLI.
4303 *BASE_ALIGN is a running maximum of the alignments of
4304 any base class. OFFSETS gives the location of empty base
4305 subobjects. T is the most derived type. Return nonzero if the new
4306 object cannot be nearly-empty. A new FIELD_DECL is inserted at
4307 *NEXT_FIELD, unless BINFO is for an empty base class.
4308
4309 Returns the location at which the next field should be inserted. */
4310
4311 static tree *
build_base_field(record_layout_info rli,tree binfo,splay_tree offsets,tree * next_field)4312 build_base_field (record_layout_info rli, tree binfo,
4313 splay_tree offsets, tree *next_field)
4314 {
4315 tree t = rli->t;
4316 tree basetype = BINFO_TYPE (binfo);
4317
4318 if (!COMPLETE_TYPE_P (basetype))
4319 /* This error is now reported in xref_tag, thus giving better
4320 location information. */
4321 return next_field;
4322
4323 /* Place the base class. */
4324 if (!is_empty_class (basetype))
4325 {
4326 tree decl;
4327
4328 /* The containing class is non-empty because it has a non-empty
4329 base class. */
4330 CLASSTYPE_EMPTY_P (t) = 0;
4331
4332 /* Create the FIELD_DECL. */
4333 decl = build_base_field_1 (t, basetype, next_field);
4334
4335 /* Try to place the field. It may take more than one try if we
4336 have a hard time placing the field without putting two
4337 objects of the same type at the same address. */
4338 layout_nonempty_base_or_field (rli, decl, binfo, offsets);
4339 }
4340 else
4341 {
4342 bool atend = layout_empty_base_or_field (rli, binfo, offsets);
4343 /* A nearly-empty class "has no proper base class that is empty,
4344 not morally virtual, and at an offset other than zero." */
4345 if (!BINFO_VIRTUAL_P (binfo) && CLASSTYPE_NEARLY_EMPTY_P (t))
4346 {
4347 if (atend)
4348 CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
4349 /* The check above (used in G++ 3.2) is insufficient because
4350 an empty class placed at offset zero might itself have an
4351 empty base at a nonzero offset. */
4352 else if (walk_subobject_offsets (basetype,
4353 empty_base_at_nonzero_offset_p,
4354 size_zero_node,
4355 /*offsets=*/NULL,
4356 /*max_offset=*/NULL_TREE,
4357 /*vbases_p=*/true))
4358 CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
4359 }
4360
4361 /* We used to not create a FIELD_DECL for empty base classes because of
4362 back end issues with overlapping FIELD_DECLs, but that doesn't seem to
4363 be a problem anymore. We need them to handle initialization of C++17
4364 aggregate bases. */
4365 if (cxx_dialect >= cxx17 && !BINFO_VIRTUAL_P (binfo))
4366 {
4367 tree decl = build_base_field_1 (t, basetype, next_field);
4368 DECL_FIELD_OFFSET (decl) = BINFO_OFFSET (binfo);
4369 DECL_FIELD_BIT_OFFSET (decl) = bitsize_zero_node;
4370 SET_DECL_OFFSET_ALIGN (decl, BITS_PER_UNIT);
4371 }
4372
4373 /* An empty virtual base causes a class to be non-empty
4374 -- but in that case we do not need to clear CLASSTYPE_EMPTY_P
4375 here because that was already done when the virtual table
4376 pointer was created. */
4377 }
4378
4379 /* Record the offsets of BINFO and its base subobjects. */
4380 record_subobject_offsets (binfo, offsets);
4381
4382 return next_field;
4383 }
4384
4385 /* Layout all of the non-virtual base classes. Record empty
4386 subobjects in OFFSETS. T is the most derived type. Return nonzero
4387 if the type cannot be nearly empty. The fields created
4388 corresponding to the base classes will be inserted at
4389 *NEXT_FIELD. */
4390
4391 static void
build_base_fields(record_layout_info rli,splay_tree offsets,tree * next_field)4392 build_base_fields (record_layout_info rli,
4393 splay_tree offsets, tree *next_field)
4394 {
4395 /* Chain to hold all the new FIELD_DECLs which stand in for base class
4396 subobjects. */
4397 tree t = rli->t;
4398 int n_baseclasses = BINFO_N_BASE_BINFOS (TYPE_BINFO (t));
4399 int i;
4400
4401 /* The primary base class is always allocated first. */
4402 if (CLASSTYPE_HAS_PRIMARY_BASE_P (t))
4403 next_field = build_base_field (rli, CLASSTYPE_PRIMARY_BINFO (t),
4404 offsets, next_field);
4405
4406 /* Now allocate the rest of the bases. */
4407 for (i = 0; i < n_baseclasses; ++i)
4408 {
4409 tree base_binfo;
4410
4411 base_binfo = BINFO_BASE_BINFO (TYPE_BINFO (t), i);
4412
4413 /* The primary base was already allocated above, so we don't
4414 need to allocate it again here. */
4415 if (base_binfo == CLASSTYPE_PRIMARY_BINFO (t))
4416 continue;
4417
4418 /* Virtual bases are added at the end (a primary virtual base
4419 will have already been added). */
4420 if (BINFO_VIRTUAL_P (base_binfo))
4421 continue;
4422
4423 next_field = build_base_field (rli, base_binfo,
4424 offsets, next_field);
4425 }
4426 }
4427
4428 /* Go through the TYPE_FIELDS of T issuing any appropriate
4429 diagnostics, figuring out which methods override which other
4430 methods, and so forth. */
4431
4432 static void
check_methods(tree t)4433 check_methods (tree t)
4434 {
4435 for (tree x = TYPE_FIELDS (t); x; x = DECL_CHAIN (x))
4436 if (DECL_DECLARES_FUNCTION_P (x))
4437 {
4438 check_for_override (x, t);
4439
4440 if (DECL_PURE_VIRTUAL_P (x)
4441 && (TREE_CODE (x) != FUNCTION_DECL || ! DECL_VINDEX (x)))
4442 error ("initializer specified for non-virtual method %q+D", x);
4443 /* The name of the field is the original field name
4444 Save this in auxiliary field for later overloading. */
4445 if (TREE_CODE (x) == FUNCTION_DECL && DECL_VINDEX (x))
4446 {
4447 TYPE_POLYMORPHIC_P (t) = 1;
4448 if (DECL_PURE_VIRTUAL_P (x))
4449 vec_safe_push (CLASSTYPE_PURE_VIRTUALS (t), x);
4450 }
4451
4452 /* All user-provided destructors are non-trivial.
4453 Constructors and assignment ops are handled in
4454 grok_special_member_properties. */
4455 if (DECL_DESTRUCTOR_P (x) && user_provided_p (x))
4456 TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t) = 1;
4457 if (!DECL_VIRTUAL_P (x)
4458 && lookup_attribute ("transaction_safe_dynamic",
4459 DECL_ATTRIBUTES (x)))
4460 error_at (DECL_SOURCE_LOCATION (x),
4461 "%<transaction_safe_dynamic%> may only be specified for "
4462 "a virtual function");
4463 }
4464 }
4465
4466 /* FN is a constructor or destructor. Clone the declaration to create
4467 a specialized in-charge or not-in-charge version, as indicated by
4468 NAME. */
4469
4470 static tree
build_clone(tree fn,tree name)4471 build_clone (tree fn, tree name)
4472 {
4473 tree parms;
4474 tree clone;
4475
4476 /* Copy the function. */
4477 clone = copy_decl (fn);
4478 /* Reset the function name. */
4479 DECL_NAME (clone) = name;
4480 /* Remember where this function came from. */
4481 DECL_ABSTRACT_ORIGIN (clone) = fn;
4482 /* Make it easy to find the CLONE given the FN. */
4483 DECL_CHAIN (clone) = DECL_CHAIN (fn);
4484 DECL_CHAIN (fn) = clone;
4485
4486 /* If this is a template, do the rest on the DECL_TEMPLATE_RESULT. */
4487 if (TREE_CODE (clone) == TEMPLATE_DECL)
4488 {
4489 tree result = build_clone (DECL_TEMPLATE_RESULT (clone), name);
4490 DECL_TEMPLATE_RESULT (clone) = result;
4491 DECL_TEMPLATE_INFO (result) = copy_node (DECL_TEMPLATE_INFO (result));
4492 DECL_TI_TEMPLATE (result) = clone;
4493 TREE_TYPE (clone) = TREE_TYPE (result);
4494 return clone;
4495 }
4496 else
4497 {
4498 // Clone constraints.
4499 if (flag_concepts)
4500 if (tree ci = get_constraints (fn))
4501 set_constraints (clone, copy_node (ci));
4502 }
4503
4504
4505 SET_DECL_ASSEMBLER_NAME (clone, NULL_TREE);
4506 DECL_CLONED_FUNCTION (clone) = fn;
4507 /* There's no pending inline data for this function. */
4508 DECL_PENDING_INLINE_INFO (clone) = NULL;
4509 DECL_PENDING_INLINE_P (clone) = 0;
4510
4511 /* The base-class destructor is not virtual. */
4512 if (name == base_dtor_identifier)
4513 {
4514 DECL_VIRTUAL_P (clone) = 0;
4515 if (TREE_CODE (clone) != TEMPLATE_DECL)
4516 DECL_VINDEX (clone) = NULL_TREE;
4517 }
4518
4519 bool ctor_omit_inherited_parms_p = ctor_omit_inherited_parms (clone);
4520 if (ctor_omit_inherited_parms_p)
4521 gcc_assert (DECL_HAS_IN_CHARGE_PARM_P (clone));
4522
4523 /* If there was an in-charge parameter, drop it from the function
4524 type. */
4525 if (DECL_HAS_IN_CHARGE_PARM_P (clone))
4526 {
4527 tree basetype = TYPE_METHOD_BASETYPE (TREE_TYPE (clone));
4528 tree parmtypes = TYPE_ARG_TYPES (TREE_TYPE (clone));
4529 /* Skip the `this' parameter. */
4530 parmtypes = TREE_CHAIN (parmtypes);
4531 /* Skip the in-charge parameter. */
4532 parmtypes = TREE_CHAIN (parmtypes);
4533 /* And the VTT parm, in a complete [cd]tor. */
4534 if (DECL_HAS_VTT_PARM_P (fn)
4535 && ! DECL_NEEDS_VTT_PARM_P (clone))
4536 parmtypes = TREE_CHAIN (parmtypes);
4537 if (ctor_omit_inherited_parms_p)
4538 {
4539 /* If we're omitting inherited parms, that just leaves the VTT. */
4540 gcc_assert (DECL_NEEDS_VTT_PARM_P (clone));
4541 parmtypes = tree_cons (NULL_TREE, vtt_parm_type, void_list_node);
4542 }
4543 TREE_TYPE (clone)
4544 = build_method_type_directly (basetype,
4545 TREE_TYPE (TREE_TYPE (clone)),
4546 parmtypes);
4547 TREE_TYPE (clone)
4548 = cp_build_type_attribute_variant (TREE_TYPE (clone),
4549 TYPE_ATTRIBUTES (TREE_TYPE (fn)));
4550 TREE_TYPE (clone)
4551 = cxx_copy_lang_qualifiers (TREE_TYPE (clone), TREE_TYPE (fn));
4552 }
4553
4554 /* Copy the function parameters. */
4555 DECL_ARGUMENTS (clone) = copy_list (DECL_ARGUMENTS (clone));
4556 /* Remove the in-charge parameter. */
4557 if (DECL_HAS_IN_CHARGE_PARM_P (clone))
4558 {
4559 DECL_CHAIN (DECL_ARGUMENTS (clone))
4560 = DECL_CHAIN (DECL_CHAIN (DECL_ARGUMENTS (clone)));
4561 DECL_HAS_IN_CHARGE_PARM_P (clone) = 0;
4562 }
4563 /* And the VTT parm, in a complete [cd]tor. */
4564 if (DECL_HAS_VTT_PARM_P (fn))
4565 {
4566 if (DECL_NEEDS_VTT_PARM_P (clone))
4567 DECL_HAS_VTT_PARM_P (clone) = 1;
4568 else
4569 {
4570 DECL_CHAIN (DECL_ARGUMENTS (clone))
4571 = DECL_CHAIN (DECL_CHAIN (DECL_ARGUMENTS (clone)));
4572 DECL_HAS_VTT_PARM_P (clone) = 0;
4573 }
4574 }
4575
4576 /* A base constructor inheriting from a virtual base doesn't get the
4577 arguments. */
4578 if (ctor_omit_inherited_parms_p)
4579 DECL_CHAIN (DECL_CHAIN (DECL_ARGUMENTS (clone))) = NULL_TREE;
4580
4581 for (parms = DECL_ARGUMENTS (clone); parms; parms = DECL_CHAIN (parms))
4582 {
4583 DECL_CONTEXT (parms) = clone;
4584 cxx_dup_lang_specific_decl (parms);
4585 }
4586
4587 /* Create the RTL for this function. */
4588 SET_DECL_RTL (clone, NULL);
4589 rest_of_decl_compilation (clone, /*top_level=*/1, at_eof);
4590
4591 return clone;
4592 }
4593
4594 /* Implementation of DECL_CLONED_FUNCTION and DECL_CLONED_FUNCTION_P, do
4595 not invoke this function directly.
4596
4597 For a non-thunk function, returns the address of the slot for storing
4598 the function it is a clone of. Otherwise returns NULL_TREE.
4599
4600 If JUST_TESTING, looks through TEMPLATE_DECL and returns NULL if
4601 cloned_function is unset. This is to support the separate
4602 DECL_CLONED_FUNCTION and DECL_CLONED_FUNCTION_P modes; using the latter
4603 on a template makes sense, but not the former. */
4604
4605 tree *
decl_cloned_function_p(const_tree decl,bool just_testing)4606 decl_cloned_function_p (const_tree decl, bool just_testing)
4607 {
4608 tree *ptr;
4609 if (just_testing)
4610 decl = STRIP_TEMPLATE (decl);
4611
4612 if (TREE_CODE (decl) != FUNCTION_DECL
4613 || !DECL_LANG_SPECIFIC (decl)
4614 || DECL_LANG_SPECIFIC (decl)->u.fn.thunk_p)
4615 {
4616 #if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
4617 if (!just_testing)
4618 lang_check_failed (__FILE__, __LINE__, __FUNCTION__);
4619 else
4620 #endif
4621 return NULL;
4622 }
4623
4624 ptr = &DECL_LANG_SPECIFIC (decl)->u.fn.u5.cloned_function;
4625 if (just_testing && *ptr == NULL_TREE)
4626 return NULL;
4627 else
4628 return ptr;
4629 }
4630
4631 /* Produce declarations for all appropriate clones of FN. If
4632 UPDATE_METHODS is true, the clones are added to the
4633 CLASSTYPE_MEMBER_VEC. */
4634
4635 void
clone_function_decl(tree fn,bool update_methods)4636 clone_function_decl (tree fn, bool update_methods)
4637 {
4638 tree clone;
4639
4640 /* Avoid inappropriate cloning. */
4641 if (DECL_CHAIN (fn)
4642 && DECL_CLONED_FUNCTION_P (DECL_CHAIN (fn)))
4643 return;
4644
4645 if (DECL_MAYBE_IN_CHARGE_CONSTRUCTOR_P (fn))
4646 {
4647 /* For each constructor, we need two variants: an in-charge version
4648 and a not-in-charge version. */
4649 clone = build_clone (fn, complete_ctor_identifier);
4650 if (update_methods)
4651 add_method (DECL_CONTEXT (clone), clone, false);
4652 clone = build_clone (fn, base_ctor_identifier);
4653 if (update_methods)
4654 add_method (DECL_CONTEXT (clone), clone, false);
4655 }
4656 else
4657 {
4658 gcc_assert (DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (fn));
4659
4660 /* For each destructor, we need three variants: an in-charge
4661 version, a not-in-charge version, and an in-charge deleting
4662 version. We clone the deleting version first because that
4663 means it will go second on the TYPE_FIELDS list -- and that
4664 corresponds to the correct layout order in the virtual
4665 function table.
4666
4667 For a non-virtual destructor, we do not build a deleting
4668 destructor. */
4669 if (DECL_VIRTUAL_P (fn))
4670 {
4671 clone = build_clone (fn, deleting_dtor_identifier);
4672 if (update_methods)
4673 add_method (DECL_CONTEXT (clone), clone, false);
4674 }
4675 clone = build_clone (fn, complete_dtor_identifier);
4676 if (update_methods)
4677 add_method (DECL_CONTEXT (clone), clone, false);
4678 clone = build_clone (fn, base_dtor_identifier);
4679 if (update_methods)
4680 add_method (DECL_CONTEXT (clone), clone, false);
4681 }
4682
4683 /* Note that this is an abstract function that is never emitted. */
4684 DECL_ABSTRACT_P (fn) = true;
4685 }
4686
4687 /* DECL is an in charge constructor, which is being defined. This will
4688 have had an in class declaration, from whence clones were
4689 declared. An out-of-class definition can specify additional default
4690 arguments. As it is the clones that are involved in overload
4691 resolution, we must propagate the information from the DECL to its
4692 clones. */
4693
4694 void
adjust_clone_args(tree decl)4695 adjust_clone_args (tree decl)
4696 {
4697 tree clone;
4698
4699 for (clone = DECL_CHAIN (decl); clone && DECL_CLONED_FUNCTION_P (clone);
4700 clone = DECL_CHAIN (clone))
4701 {
4702 tree orig_clone_parms = TYPE_ARG_TYPES (TREE_TYPE (clone));
4703 tree orig_decl_parms = TYPE_ARG_TYPES (TREE_TYPE (decl));
4704 tree decl_parms, clone_parms;
4705
4706 clone_parms = orig_clone_parms;
4707
4708 /* Skip the 'this' parameter. */
4709 orig_clone_parms = TREE_CHAIN (orig_clone_parms);
4710 orig_decl_parms = TREE_CHAIN (orig_decl_parms);
4711
4712 if (DECL_HAS_IN_CHARGE_PARM_P (decl))
4713 orig_decl_parms = TREE_CHAIN (orig_decl_parms);
4714 if (DECL_HAS_VTT_PARM_P (decl))
4715 orig_decl_parms = TREE_CHAIN (orig_decl_parms);
4716
4717 clone_parms = orig_clone_parms;
4718 if (DECL_HAS_VTT_PARM_P (clone))
4719 clone_parms = TREE_CHAIN (clone_parms);
4720
4721 for (decl_parms = orig_decl_parms; decl_parms;
4722 decl_parms = TREE_CHAIN (decl_parms),
4723 clone_parms = TREE_CHAIN (clone_parms))
4724 {
4725 if (clone_parms == void_list_node)
4726 {
4727 gcc_assert (decl_parms == clone_parms
4728 || ctor_omit_inherited_parms (clone));
4729 break;
4730 }
4731
4732 gcc_assert (same_type_p (TREE_TYPE (decl_parms),
4733 TREE_TYPE (clone_parms)));
4734
4735 if (TREE_PURPOSE (decl_parms) && !TREE_PURPOSE (clone_parms))
4736 {
4737 /* A default parameter has been added. Adjust the
4738 clone's parameters. */
4739 clone_parms = orig_decl_parms;
4740
4741 if (DECL_HAS_VTT_PARM_P (clone))
4742 {
4743 clone_parms = tree_cons (TREE_PURPOSE (orig_clone_parms),
4744 TREE_VALUE (orig_clone_parms),
4745 clone_parms);
4746 TREE_TYPE (clone_parms) = TREE_TYPE (orig_clone_parms);
4747 }
4748
4749 tree basetype = TYPE_METHOD_BASETYPE (TREE_TYPE (clone));
4750 tree type
4751 = build_method_type_directly (basetype,
4752 TREE_TYPE (TREE_TYPE (clone)),
4753 clone_parms);
4754 if (tree attrs = TYPE_ATTRIBUTES (TREE_TYPE (clone)))
4755 type = cp_build_type_attribute_variant (type, attrs);
4756 type = cxx_copy_lang_qualifiers (type, TREE_TYPE (clone));
4757 TREE_TYPE (clone) = type;
4758
4759 clone_parms = NULL_TREE;
4760 break;
4761 }
4762 }
4763 gcc_assert (!clone_parms || clone_parms == void_list_node);
4764 }
4765 }
4766
4767 /* For each of the constructors and destructors in T, create an
4768 in-charge and not-in-charge variant. */
4769
4770 static void
clone_constructors_and_destructors(tree t)4771 clone_constructors_and_destructors (tree t)
4772 {
4773 /* While constructors can be via a using declaration, at this point
4774 we no longer need to know that. */
4775 for (ovl_iterator iter (CLASSTYPE_CONSTRUCTORS (t)); iter; ++iter)
4776 clone_function_decl (*iter, /*update_methods=*/true);
4777
4778 if (tree dtor = CLASSTYPE_DESTRUCTOR (t))
4779 clone_function_decl (dtor, /*update_methods=*/true);
4780 }
4781
4782 /* Deduce noexcept for a destructor DTOR. */
4783
4784 void
deduce_noexcept_on_destructor(tree dtor)4785 deduce_noexcept_on_destructor (tree dtor)
4786 {
4787 if (!TYPE_RAISES_EXCEPTIONS (TREE_TYPE (dtor)))
4788 TREE_TYPE (dtor) = build_exception_variant (TREE_TYPE (dtor),
4789 noexcept_deferred_spec);
4790 }
4791
4792 /* Subroutine of set_one_vmethod_tm_attributes. Search base classes
4793 of TYPE for virtual functions which FNDECL overrides. Return a
4794 mask of the tm attributes found therein. */
4795
4796 static int
look_for_tm_attr_overrides(tree type,tree fndecl)4797 look_for_tm_attr_overrides (tree type, tree fndecl)
4798 {
4799 tree binfo = TYPE_BINFO (type);
4800 tree base_binfo;
4801 int ix, found = 0;
4802
4803 for (ix = 0; BINFO_BASE_ITERATE (binfo, ix, base_binfo); ++ix)
4804 {
4805 tree o, basetype = BINFO_TYPE (base_binfo);
4806
4807 if (!TYPE_POLYMORPHIC_P (basetype))
4808 continue;
4809
4810 o = look_for_overrides_here (basetype, fndecl);
4811 if (o)
4812 {
4813 if (lookup_attribute ("transaction_safe_dynamic",
4814 DECL_ATTRIBUTES (o)))
4815 /* transaction_safe_dynamic is not inherited. */;
4816 else
4817 found |= tm_attr_to_mask (find_tm_attribute
4818 (TYPE_ATTRIBUTES (TREE_TYPE (o))));
4819 }
4820 else
4821 found |= look_for_tm_attr_overrides (basetype, fndecl);
4822 }
4823
4824 return found;
4825 }
4826
4827 /* Subroutine of set_method_tm_attributes. Handle the checks and
4828 inheritance for one virtual method FNDECL. */
4829
4830 static void
set_one_vmethod_tm_attributes(tree type,tree fndecl)4831 set_one_vmethod_tm_attributes (tree type, tree fndecl)
4832 {
4833 tree tm_attr;
4834 int found, have;
4835
4836 found = look_for_tm_attr_overrides (type, fndecl);
4837
4838 /* If FNDECL doesn't actually override anything (i.e. T is the
4839 class that first declares FNDECL virtual), then we're done. */
4840 if (found == 0)
4841 return;
4842
4843 tm_attr = find_tm_attribute (TYPE_ATTRIBUTES (TREE_TYPE (fndecl)));
4844 have = tm_attr_to_mask (tm_attr);
4845
4846 /* Intel STM Language Extension 3.0, Section 4.2 table 4:
4847 tm_pure must match exactly, otherwise no weakening of
4848 tm_safe > tm_callable > nothing. */
4849 /* ??? The tm_pure attribute didn't make the transition to the
4850 multivendor language spec. */
4851 if (have == TM_ATTR_PURE)
4852 {
4853 if (found != TM_ATTR_PURE)
4854 {
4855 found &= -found;
4856 goto err_override;
4857 }
4858 }
4859 /* If the overridden function is tm_pure, then FNDECL must be. */
4860 else if (found == TM_ATTR_PURE && tm_attr)
4861 goto err_override;
4862 /* Look for base class combinations that cannot be satisfied. */
4863 else if (found != TM_ATTR_PURE && (found & TM_ATTR_PURE))
4864 {
4865 found &= ~TM_ATTR_PURE;
4866 found &= -found;
4867 error_at (DECL_SOURCE_LOCATION (fndecl),
4868 "method overrides both %<transaction_pure%> and %qE methods",
4869 tm_mask_to_attr (found));
4870 }
4871 /* If FNDECL did not declare an attribute, then inherit the most
4872 restrictive one. */
4873 else if (tm_attr == NULL)
4874 {
4875 apply_tm_attr (fndecl, tm_mask_to_attr (least_bit_hwi (found)));
4876 }
4877 /* Otherwise validate that we're not weaker than a function
4878 that is being overridden. */
4879 else
4880 {
4881 found &= -found;
4882 if (found <= TM_ATTR_CALLABLE && have > found)
4883 goto err_override;
4884 }
4885 return;
4886
4887 err_override:
4888 error_at (DECL_SOURCE_LOCATION (fndecl),
4889 "method declared %qE overriding %qE method",
4890 tm_attr, tm_mask_to_attr (found));
4891 }
4892
4893 /* For each of the methods in T, propagate a class-level tm attribute. */
4894
4895 static void
set_method_tm_attributes(tree t)4896 set_method_tm_attributes (tree t)
4897 {
4898 tree class_tm_attr, fndecl;
4899
4900 /* Don't bother collecting tm attributes if transactional memory
4901 support is not enabled. */
4902 if (!flag_tm)
4903 return;
4904
4905 /* Process virtual methods first, as they inherit directly from the
4906 base virtual function and also require validation of new attributes. */
4907 if (TYPE_CONTAINS_VPTR_P (t))
4908 {
4909 tree vchain;
4910 for (vchain = BINFO_VIRTUALS (TYPE_BINFO (t)); vchain;
4911 vchain = TREE_CHAIN (vchain))
4912 {
4913 fndecl = BV_FN (vchain);
4914 if (DECL_THUNK_P (fndecl))
4915 fndecl = THUNK_TARGET (fndecl);
4916 set_one_vmethod_tm_attributes (t, fndecl);
4917 }
4918 }
4919
4920 /* If the class doesn't have an attribute, nothing more to do. */
4921 class_tm_attr = find_tm_attribute (TYPE_ATTRIBUTES (t));
4922 if (class_tm_attr == NULL)
4923 return;
4924
4925 /* Any method that does not yet have a tm attribute inherits
4926 the one from the class. */
4927 for (fndecl = TYPE_FIELDS (t); fndecl; fndecl = DECL_CHAIN (fndecl))
4928 if (DECL_DECLARES_FUNCTION_P (fndecl)
4929 && !find_tm_attribute (TYPE_ATTRIBUTES (TREE_TYPE (fndecl))))
4930 apply_tm_attr (fndecl, class_tm_attr);
4931 }
4932
4933 /* Returns true if FN is a default constructor. */
4934
4935 bool
default_ctor_p(tree fn)4936 default_ctor_p (tree fn)
4937 {
4938 return (DECL_CONSTRUCTOR_P (fn)
4939 && sufficient_parms_p (FUNCTION_FIRST_USER_PARMTYPE (fn)));
4940 }
4941
4942 /* Returns true iff class T has a user-provided constructor that can be called
4943 with more than zero arguments. */
4944
4945 bool
type_has_user_nondefault_constructor(tree t)4946 type_has_user_nondefault_constructor (tree t)
4947 {
4948 if (!TYPE_HAS_USER_CONSTRUCTOR (t))
4949 return false;
4950
4951 for (ovl_iterator iter (CLASSTYPE_CONSTRUCTORS (t)); iter; ++iter)
4952 {
4953 tree fn = *iter;
4954 if (user_provided_p (fn)
4955 && (TREE_CODE (fn) == TEMPLATE_DECL
4956 || (skip_artificial_parms_for (fn, DECL_ARGUMENTS (fn))
4957 != NULL_TREE)))
4958 return true;
4959 }
4960
4961 return false;
4962 }
4963
4964 /* Returns the defaulted constructor if T has one. Otherwise, returns
4965 NULL_TREE. */
4966
4967 tree
in_class_defaulted_default_constructor(tree t)4968 in_class_defaulted_default_constructor (tree t)
4969 {
4970 if (!TYPE_HAS_USER_CONSTRUCTOR (t))
4971 return NULL_TREE;
4972
4973 for (ovl_iterator iter (CLASSTYPE_CONSTRUCTORS (t)); iter; ++iter)
4974 {
4975 tree fn = *iter;
4976
4977 if (DECL_DEFAULTED_IN_CLASS_P (fn)
4978 && default_ctor_p (fn))
4979 return fn;
4980 }
4981
4982 return NULL_TREE;
4983 }
4984
4985 /* Returns true iff FN is a user-provided function, i.e. user-declared
4986 and not defaulted at its first declaration. */
4987
4988 bool
user_provided_p(tree fn)4989 user_provided_p (tree fn)
4990 {
4991 if (TREE_CODE (fn) == TEMPLATE_DECL)
4992 return true;
4993 else
4994 return (!DECL_ARTIFICIAL (fn)
4995 && !(DECL_INITIALIZED_IN_CLASS_P (fn)
4996 && (DECL_DEFAULTED_FN (fn) || DECL_DELETED_FN (fn))));
4997 }
4998
4999 /* Returns true iff class T has a user-provided constructor. */
5000
5001 bool
type_has_user_provided_constructor(tree t)5002 type_has_user_provided_constructor (tree t)
5003 {
5004 if (!CLASS_TYPE_P (t))
5005 return false;
5006
5007 if (!TYPE_HAS_USER_CONSTRUCTOR (t))
5008 return false;
5009
5010 for (ovl_iterator iter (CLASSTYPE_CONSTRUCTORS (t)); iter; ++iter)
5011 if (user_provided_p (*iter))
5012 return true;
5013
5014 return false;
5015 }
5016
5017 /* Returns true iff class T has a user-provided or explicit constructor. */
5018
5019 bool
type_has_user_provided_or_explicit_constructor(tree t)5020 type_has_user_provided_or_explicit_constructor (tree t)
5021 {
5022 if (!CLASS_TYPE_P (t))
5023 return false;
5024
5025 if (!TYPE_HAS_USER_CONSTRUCTOR (t))
5026 return false;
5027
5028 for (ovl_iterator iter (CLASSTYPE_CONSTRUCTORS (t)); iter; ++iter)
5029 {
5030 tree fn = *iter;
5031 if (user_provided_p (fn) || DECL_NONCONVERTING_P (fn))
5032 return true;
5033 }
5034
5035 return false;
5036 }
5037
5038 /* Returns true iff class T has a non-user-provided (i.e. implicitly
5039 declared or explicitly defaulted in the class body) default
5040 constructor. */
5041
5042 bool
type_has_non_user_provided_default_constructor(tree t)5043 type_has_non_user_provided_default_constructor (tree t)
5044 {
5045 if (!TYPE_HAS_DEFAULT_CONSTRUCTOR (t))
5046 return false;
5047 if (CLASSTYPE_LAZY_DEFAULT_CTOR (t))
5048 return true;
5049
5050 for (ovl_iterator iter (CLASSTYPE_CONSTRUCTORS (t)); iter; ++iter)
5051 {
5052 tree fn = *iter;
5053 if (TREE_CODE (fn) == FUNCTION_DECL
5054 && default_ctor_p (fn)
5055 && !user_provided_p (fn))
5056 return true;
5057 }
5058
5059 return false;
5060 }
5061
5062 /* TYPE is being used as a virtual base, and has a non-trivial move
5063 assignment. Return true if this is due to there being a user-provided
5064 move assignment in TYPE or one of its subobjects; if there isn't, then
5065 multiple move assignment can't cause any harm. */
5066
5067 bool
vbase_has_user_provided_move_assign(tree type)5068 vbase_has_user_provided_move_assign (tree type)
5069 {
5070 /* Does the type itself have a user-provided move assignment operator? */
5071 if (!CLASSTYPE_LAZY_MOVE_ASSIGN (type))
5072 for (ovl_iterator iter (get_class_binding_direct
5073 (type, assign_op_identifier));
5074 iter; ++iter)
5075 if (user_provided_p (*iter) && move_fn_p (*iter))
5076 return true;
5077
5078 /* Do any of its bases? */
5079 tree binfo = TYPE_BINFO (type);
5080 tree base_binfo;
5081 for (int i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
5082 if (vbase_has_user_provided_move_assign (BINFO_TYPE (base_binfo)))
5083 return true;
5084
5085 /* Or non-static data members? */
5086 for (tree field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
5087 {
5088 if (TREE_CODE (field) == FIELD_DECL
5089 && CLASS_TYPE_P (TREE_TYPE (field))
5090 && vbase_has_user_provided_move_assign (TREE_TYPE (field)))
5091 return true;
5092 }
5093
5094 /* Seems not. */
5095 return false;
5096 }
5097
5098 /* If default-initialization leaves part of TYPE uninitialized, returns
5099 a DECL for the field or TYPE itself (DR 253). */
5100
5101 tree
default_init_uninitialized_part(tree type)5102 default_init_uninitialized_part (tree type)
5103 {
5104 tree t, r, binfo;
5105 int i;
5106
5107 type = strip_array_types (type);
5108 if (!CLASS_TYPE_P (type))
5109 return type;
5110 if (!type_has_non_user_provided_default_constructor (type))
5111 return NULL_TREE;
5112 for (binfo = TYPE_BINFO (type), i = 0;
5113 BINFO_BASE_ITERATE (binfo, i, t); ++i)
5114 {
5115 r = default_init_uninitialized_part (BINFO_TYPE (t));
5116 if (r)
5117 return r;
5118 }
5119 for (t = TYPE_FIELDS (type); t; t = DECL_CHAIN (t))
5120 if (TREE_CODE (t) == FIELD_DECL
5121 && !DECL_ARTIFICIAL (t)
5122 && !DECL_INITIAL (t))
5123 {
5124 r = default_init_uninitialized_part (TREE_TYPE (t));
5125 if (r)
5126 return DECL_P (r) ? r : t;
5127 }
5128
5129 return NULL_TREE;
5130 }
5131
5132 /* Returns true iff for class T, a trivial synthesized default constructor
5133 would be constexpr. */
5134
5135 bool
trivial_default_constructor_is_constexpr(tree t)5136 trivial_default_constructor_is_constexpr (tree t)
5137 {
5138 /* A defaulted trivial default constructor is constexpr
5139 if there is nothing to initialize. */
5140 gcc_assert (!TYPE_HAS_COMPLEX_DFLT (t));
5141 /* A class with a vptr doesn't have a trivial default ctor. */
5142 return is_really_empty_class (t, /*ignore_vptr*/true);
5143 }
5144
5145 /* Returns true iff class T has a constexpr default constructor. */
5146
5147 bool
type_has_constexpr_default_constructor(tree t)5148 type_has_constexpr_default_constructor (tree t)
5149 {
5150 tree fns;
5151
5152 if (!CLASS_TYPE_P (t))
5153 {
5154 /* The caller should have stripped an enclosing array. */
5155 gcc_assert (TREE_CODE (t) != ARRAY_TYPE);
5156 return false;
5157 }
5158 if (CLASSTYPE_LAZY_DEFAULT_CTOR (t))
5159 {
5160 if (!TYPE_HAS_COMPLEX_DFLT (t))
5161 return trivial_default_constructor_is_constexpr (t);
5162 /* Non-trivial, we need to check subobject constructors. */
5163 lazily_declare_fn (sfk_constructor, t);
5164 }
5165 fns = locate_ctor (t);
5166 return (fns && DECL_DECLARED_CONSTEXPR_P (fns));
5167 }
5168
5169 /* Returns true iff class T has a constexpr default constructor or has an
5170 implicitly declared default constructor that we can't tell if it's constexpr
5171 without forcing a lazy declaration (which might cause undesired
5172 instantiations). */
5173
5174 bool
type_maybe_constexpr_default_constructor(tree t)5175 type_maybe_constexpr_default_constructor (tree t)
5176 {
5177 if (CLASS_TYPE_P (t) && CLASSTYPE_LAZY_DEFAULT_CTOR (t)
5178 && TYPE_HAS_COMPLEX_DFLT (t))
5179 /* Assume it's constexpr. */
5180 return true;
5181 return type_has_constexpr_default_constructor (t);
5182 }
5183
5184 /* Returns true iff class TYPE has a virtual destructor. */
5185
5186 bool
type_has_virtual_destructor(tree type)5187 type_has_virtual_destructor (tree type)
5188 {
5189 tree dtor;
5190
5191 if (!CLASS_TYPE_P (type))
5192 return false;
5193
5194 gcc_assert (COMPLETE_TYPE_P (type));
5195 dtor = CLASSTYPE_DESTRUCTOR (type);
5196 return (dtor && DECL_VIRTUAL_P (dtor));
5197 }
5198
5199 /* Returns true iff T, a class, has a move-assignment or
5200 move-constructor. Does not lazily declare either.
5201 If USER_P is false, any move function will do. If it is true, the
5202 move function must be user-declared.
5203
5204 Note that user-declared here is different from "user-provided",
5205 which doesn't include functions that are defaulted in the
5206 class. */
5207
5208 bool
classtype_has_move_assign_or_move_ctor_p(tree t,bool user_p)5209 classtype_has_move_assign_or_move_ctor_p (tree t, bool user_p)
5210 {
5211 gcc_assert (user_p
5212 || (!CLASSTYPE_LAZY_MOVE_CTOR (t)
5213 && !CLASSTYPE_LAZY_MOVE_ASSIGN (t)));
5214
5215 if (!CLASSTYPE_LAZY_MOVE_CTOR (t))
5216 for (ovl_iterator iter (CLASSTYPE_CONSTRUCTORS (t)); iter; ++iter)
5217 if ((!user_p || !DECL_ARTIFICIAL (*iter)) && move_fn_p (*iter))
5218 return true;
5219
5220 if (!CLASSTYPE_LAZY_MOVE_ASSIGN (t))
5221 for (ovl_iterator iter (get_class_binding_direct
5222 (t, assign_op_identifier));
5223 iter; ++iter)
5224 if ((!user_p || !DECL_ARTIFICIAL (*iter))
5225 && DECL_CONTEXT (*iter) == t
5226 && move_fn_p (*iter))
5227 return true;
5228
5229 return false;
5230 }
5231
5232 /* True iff T has a move constructor that is not deleted. */
5233
5234 bool
classtype_has_non_deleted_move_ctor(tree t)5235 classtype_has_non_deleted_move_ctor (tree t)
5236 {
5237 if (CLASSTYPE_LAZY_MOVE_CTOR (t))
5238 lazily_declare_fn (sfk_move_constructor, t);
5239 for (ovl_iterator iter (CLASSTYPE_CONSTRUCTORS (t)); iter; ++iter)
5240 if (move_fn_p (*iter) && !DECL_DELETED_FN (*iter))
5241 return true;
5242 return false;
5243 }
5244
5245 /* If T, a class, has a user-provided copy constructor, copy assignment
5246 operator, or destructor, returns that function. Otherwise, null. */
5247
5248 tree
classtype_has_depr_implicit_copy(tree t)5249 classtype_has_depr_implicit_copy (tree t)
5250 {
5251 if (!CLASSTYPE_LAZY_COPY_CTOR (t))
5252 for (ovl_iterator iter (CLASSTYPE_CONSTRUCTORS (t)); iter; ++iter)
5253 {
5254 tree fn = *iter;
5255 if (user_provided_p (fn) && copy_fn_p (fn))
5256 return fn;
5257 }
5258
5259 if (!CLASSTYPE_LAZY_COPY_ASSIGN (t))
5260 for (ovl_iterator iter (get_class_binding_direct
5261 (t, assign_op_identifier));
5262 iter; ++iter)
5263 {
5264 tree fn = *iter;
5265 if (user_provided_p (fn) && copy_fn_p (fn))
5266 return fn;
5267 }
5268
5269 if (!CLASSTYPE_LAZY_DESTRUCTOR (t))
5270 {
5271 tree fn = CLASSTYPE_DESTRUCTOR (t);
5272 if (user_provided_p (fn))
5273 return fn;
5274 }
5275
5276 return NULL_TREE;
5277 }
5278
5279 /* Nonzero if we need to build up a constructor call when initializing an
5280 object of this class, either because it has a user-declared constructor
5281 or because it doesn't have a default constructor (so we need to give an
5282 error if no initializer is provided). Use TYPE_NEEDS_CONSTRUCTING when
5283 what you care about is whether or not an object can be produced by a
5284 constructor (e.g. so we don't set TREE_READONLY on const variables of
5285 such type); use this function when what you care about is whether or not
5286 to try to call a constructor to create an object. The latter case is
5287 the former plus some cases of constructors that cannot be called. */
5288
5289 bool
type_build_ctor_call(tree t)5290 type_build_ctor_call (tree t)
5291 {
5292 tree inner;
5293 if (TYPE_NEEDS_CONSTRUCTING (t))
5294 return true;
5295 inner = strip_array_types (t);
5296 if (!CLASS_TYPE_P (inner) || ANON_AGGR_TYPE_P (inner))
5297 return false;
5298 if (!TYPE_HAS_DEFAULT_CONSTRUCTOR (inner))
5299 return true;
5300 if (cxx_dialect < cxx11)
5301 return false;
5302 /* A user-declared constructor might be private, and a constructor might
5303 be trivial but deleted. */
5304 for (ovl_iterator iter (get_class_binding (inner, complete_ctor_identifier));
5305 iter; ++iter)
5306 {
5307 tree fn = *iter;
5308 if (!DECL_ARTIFICIAL (fn)
5309 || TREE_DEPRECATED (fn)
5310 || DECL_DELETED_FN (fn))
5311 return true;
5312 }
5313 return false;
5314 }
5315
5316 /* Like type_build_ctor_call, but for destructors. */
5317
5318 bool
type_build_dtor_call(tree t)5319 type_build_dtor_call (tree t)
5320 {
5321 tree inner;
5322 if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t))
5323 return true;
5324 inner = strip_array_types (t);
5325 if (!CLASS_TYPE_P (inner) || ANON_AGGR_TYPE_P (inner)
5326 || !COMPLETE_TYPE_P (inner))
5327 return false;
5328 if (cxx_dialect < cxx11)
5329 return false;
5330 /* A user-declared destructor might be private, and a destructor might
5331 be trivial but deleted. */
5332 for (ovl_iterator iter (get_class_binding (inner, complete_dtor_identifier));
5333 iter; ++iter)
5334 {
5335 tree fn = *iter;
5336 if (!DECL_ARTIFICIAL (fn)
5337 || TREE_DEPRECATED (fn)
5338 || DECL_DELETED_FN (fn))
5339 return true;
5340 }
5341 return false;
5342 }
5343
5344 /* Remove all zero-width bit-fields from T. */
5345
5346 static void
remove_zero_width_bit_fields(tree t)5347 remove_zero_width_bit_fields (tree t)
5348 {
5349 tree *fieldsp;
5350
5351 fieldsp = &TYPE_FIELDS (t);
5352 while (*fieldsp)
5353 {
5354 if (TREE_CODE (*fieldsp) == FIELD_DECL
5355 && DECL_C_BIT_FIELD (*fieldsp)
5356 /* We should not be confused by the fact that grokbitfield
5357 temporarily sets the width of the bit field into
5358 DECL_BIT_FIELD_REPRESENTATIVE (*fieldsp).
5359 check_bitfield_decl eventually sets DECL_SIZE (*fieldsp)
5360 to that width. */
5361 && (DECL_SIZE (*fieldsp) == NULL_TREE
5362 || integer_zerop (DECL_SIZE (*fieldsp))))
5363 *fieldsp = DECL_CHAIN (*fieldsp);
5364 else
5365 fieldsp = &DECL_CHAIN (*fieldsp);
5366 }
5367 }
5368
5369 /* Returns TRUE iff we need a cookie when dynamically allocating an
5370 array whose elements have the indicated class TYPE. */
5371
5372 static bool
type_requires_array_cookie(tree type)5373 type_requires_array_cookie (tree type)
5374 {
5375 tree fns;
5376 bool has_two_argument_delete_p = false;
5377
5378 gcc_assert (CLASS_TYPE_P (type));
5379
5380 /* If there's a non-trivial destructor, we need a cookie. In order
5381 to iterate through the array calling the destructor for each
5382 element, we'll have to know how many elements there are. */
5383 if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type))
5384 return true;
5385
5386 /* If the usual deallocation function is a two-argument whose second
5387 argument is of type `size_t', then we have to pass the size of
5388 the array to the deallocation function, so we will need to store
5389 a cookie. */
5390 fns = lookup_fnfields (TYPE_BINFO (type),
5391 ovl_op_identifier (false, VEC_DELETE_EXPR),
5392 /*protect=*/0);
5393 /* If there are no `operator []' members, or the lookup is
5394 ambiguous, then we don't need a cookie. */
5395 if (!fns || fns == error_mark_node)
5396 return false;
5397 /* Loop through all of the functions. */
5398 for (lkp_iterator iter (BASELINK_FUNCTIONS (fns)); iter; ++iter)
5399 {
5400 tree fn = *iter;
5401
5402 /* See if this function is a one-argument delete function. If
5403 it is, then it will be the usual deallocation function. */
5404 tree second_parm = TREE_CHAIN (TYPE_ARG_TYPES (TREE_TYPE (fn)));
5405 if (second_parm == void_list_node)
5406 return false;
5407 /* Do not consider this function if its second argument is an
5408 ellipsis. */
5409 if (!second_parm)
5410 continue;
5411 /* Otherwise, if we have a two-argument function and the second
5412 argument is `size_t', it will be the usual deallocation
5413 function -- unless there is one-argument function, too. */
5414 if (TREE_CHAIN (second_parm) == void_list_node
5415 && same_type_p (TREE_VALUE (second_parm), size_type_node))
5416 has_two_argument_delete_p = true;
5417 }
5418
5419 return has_two_argument_delete_p;
5420 }
5421
5422 /* Finish computing the `literal type' property of class type T.
5423
5424 At this point, we have already processed base classes and
5425 non-static data members. We need to check whether the copy
5426 constructor is trivial, the destructor is trivial, and there
5427 is a trivial default constructor or at least one constexpr
5428 constructor other than the copy constructor. */
5429
5430 static void
finalize_literal_type_property(tree t)5431 finalize_literal_type_property (tree t)
5432 {
5433 tree fn;
5434
5435 if (cxx_dialect < cxx11
5436 || TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t))
5437 CLASSTYPE_LITERAL_P (t) = false;
5438 else if (CLASSTYPE_LITERAL_P (t) && LAMBDA_TYPE_P (t))
5439 CLASSTYPE_LITERAL_P (t) = (cxx_dialect >= cxx17);
5440 else if (CLASSTYPE_LITERAL_P (t) && !TYPE_HAS_TRIVIAL_DFLT (t)
5441 && CLASSTYPE_NON_AGGREGATE (t)
5442 && !TYPE_HAS_CONSTEXPR_CTOR (t))
5443 CLASSTYPE_LITERAL_P (t) = false;
5444
5445 /* C++14 DR 1684 removed this restriction. */
5446 if (cxx_dialect < cxx14
5447 && !CLASSTYPE_LITERAL_P (t) && !LAMBDA_TYPE_P (t))
5448 for (fn = TYPE_FIELDS (t); fn; fn = DECL_CHAIN (fn))
5449 if (TREE_CODE (fn) == FUNCTION_DECL
5450 && DECL_DECLARED_CONSTEXPR_P (fn)
5451 && DECL_NONSTATIC_MEMBER_FUNCTION_P (fn)
5452 && !DECL_CONSTRUCTOR_P (fn))
5453 {
5454 DECL_DECLARED_CONSTEXPR_P (fn) = false;
5455 if (!DECL_GENERATED_P (fn))
5456 {
5457 auto_diagnostic_group d;
5458 if (pedwarn (DECL_SOURCE_LOCATION (fn), OPT_Wpedantic,
5459 "enclosing class of %<constexpr%> non-static "
5460 "member function %q+#D is not a literal type", fn))
5461 explain_non_literal_class (t);
5462 }
5463 }
5464 }
5465
5466 /* T is a non-literal type used in a context which requires a constant
5467 expression. Explain why it isn't literal. */
5468
5469 void
explain_non_literal_class(tree t)5470 explain_non_literal_class (tree t)
5471 {
5472 static hash_set<tree> *diagnosed;
5473
5474 if (!CLASS_TYPE_P (t))
5475 return;
5476 t = TYPE_MAIN_VARIANT (t);
5477
5478 if (diagnosed == NULL)
5479 diagnosed = new hash_set<tree>;
5480 if (diagnosed->add (t))
5481 /* Already explained. */
5482 return;
5483
5484 auto_diagnostic_group d;
5485 inform (UNKNOWN_LOCATION, "%q+T is not literal because:", t);
5486 if (cxx_dialect < cxx17 && LAMBDA_TYPE_P (t))
5487 inform (UNKNOWN_LOCATION,
5488 " %qT is a closure type, which is only literal in "
5489 "C++17 and later", t);
5490 else if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t))
5491 inform (UNKNOWN_LOCATION, " %q+T has a non-trivial destructor", t);
5492 else if (CLASSTYPE_NON_AGGREGATE (t)
5493 && !TYPE_HAS_TRIVIAL_DFLT (t)
5494 && !LAMBDA_TYPE_P (t)
5495 && !TYPE_HAS_CONSTEXPR_CTOR (t))
5496 {
5497 inform (UNKNOWN_LOCATION,
5498 " %q+T is not an aggregate, does not have a trivial "
5499 "default constructor, and has no %<constexpr%> constructor that "
5500 "is not a copy or move constructor", t);
5501 if (type_has_non_user_provided_default_constructor (t))
5502 /* Note that we can't simply call locate_ctor because when the
5503 constructor is deleted it just returns NULL_TREE. */
5504 for (ovl_iterator iter (CLASSTYPE_CONSTRUCTORS (t)); iter; ++iter)
5505 {
5506 tree fn = *iter;
5507 tree parms = TYPE_ARG_TYPES (TREE_TYPE (fn));
5508
5509 parms = skip_artificial_parms_for (fn, parms);
5510
5511 if (sufficient_parms_p (parms))
5512 {
5513 if (DECL_DELETED_FN (fn))
5514 maybe_explain_implicit_delete (fn);
5515 else
5516 explain_invalid_constexpr_fn (fn);
5517 break;
5518 }
5519 }
5520 }
5521 else
5522 {
5523 tree binfo, base_binfo, field; int i;
5524 for (binfo = TYPE_BINFO (t), i = 0;
5525 BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
5526 {
5527 tree basetype = TREE_TYPE (base_binfo);
5528 if (!CLASSTYPE_LITERAL_P (basetype))
5529 {
5530 inform (UNKNOWN_LOCATION,
5531 " base class %qT of %q+T is non-literal",
5532 basetype, t);
5533 explain_non_literal_class (basetype);
5534 return;
5535 }
5536 }
5537 for (field = TYPE_FIELDS (t); field; field = TREE_CHAIN (field))
5538 {
5539 tree ftype;
5540 if (TREE_CODE (field) != FIELD_DECL)
5541 continue;
5542 ftype = TREE_TYPE (field);
5543 if (!literal_type_p (ftype))
5544 {
5545 inform (DECL_SOURCE_LOCATION (field),
5546 " non-static data member %qD has non-literal type",
5547 field);
5548 if (CLASS_TYPE_P (ftype))
5549 explain_non_literal_class (ftype);
5550 }
5551 if (CP_TYPE_VOLATILE_P (ftype))
5552 inform (DECL_SOURCE_LOCATION (field),
5553 " non-static data member %qD has volatile type", field);
5554 }
5555 }
5556 }
5557
5558 /* Check the validity of the bases and members declared in T. Add any
5559 implicitly-generated functions (like copy-constructors and
5560 assignment operators). Compute various flag bits (like
5561 CLASSTYPE_NON_LAYOUT_POD_T) for T. This routine works purely at the C++
5562 level: i.e., independently of the ABI in use. */
5563
5564 static void
check_bases_and_members(tree t)5565 check_bases_and_members (tree t)
5566 {
5567 /* Nonzero if the implicitly generated copy constructor should take
5568 a non-const reference argument. */
5569 int cant_have_const_ctor;
5570 /* Nonzero if the implicitly generated assignment operator
5571 should take a non-const reference argument. */
5572 int no_const_asn_ref;
5573 tree access_decls;
5574 bool saved_complex_asn_ref;
5575 bool saved_nontrivial_dtor;
5576 tree fn;
5577
5578 /* By default, we use const reference arguments and generate default
5579 constructors. */
5580 cant_have_const_ctor = 0;
5581 no_const_asn_ref = 0;
5582
5583 /* Check all the base-classes and set FMEM members to point to arrays
5584 of potential interest. */
5585 check_bases (t, &cant_have_const_ctor, &no_const_asn_ref);
5586
5587 /* Deduce noexcept on destructor. This needs to happen after we've set
5588 triviality flags appropriately for our bases. */
5589 if (cxx_dialect >= cxx11)
5590 if (tree dtor = CLASSTYPE_DESTRUCTOR (t))
5591 deduce_noexcept_on_destructor (dtor);
5592
5593 /* Check all the method declarations. */
5594 check_methods (t);
5595
5596 /* Save the initial values of these flags which only indicate whether
5597 or not the class has user-provided functions. As we analyze the
5598 bases and members we can set these flags for other reasons. */
5599 saved_complex_asn_ref = TYPE_HAS_COMPLEX_COPY_ASSIGN (t);
5600 saved_nontrivial_dtor = TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t);
5601
5602 /* Check all the data member declarations. We cannot call
5603 check_field_decls until we have called check_bases check_methods,
5604 as check_field_decls depends on TYPE_HAS_NONTRIVIAL_DESTRUCTOR
5605 being set appropriately. */
5606 check_field_decls (t, &access_decls,
5607 &cant_have_const_ctor,
5608 &no_const_asn_ref);
5609
5610 /* A nearly-empty class has to be vptr-containing; a nearly empty
5611 class contains just a vptr. */
5612 if (!TYPE_CONTAINS_VPTR_P (t))
5613 CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
5614
5615 /* Do some bookkeeping that will guide the generation of implicitly
5616 declared member functions. */
5617 TYPE_HAS_COMPLEX_COPY_CTOR (t) |= TYPE_CONTAINS_VPTR_P (t);
5618 TYPE_HAS_COMPLEX_MOVE_CTOR (t) |= TYPE_CONTAINS_VPTR_P (t);
5619 /* We need to call a constructor for this class if it has a
5620 user-provided constructor, or if the default constructor is going
5621 to initialize the vptr. (This is not an if-and-only-if;
5622 TYPE_NEEDS_CONSTRUCTING is set elsewhere if bases or members
5623 themselves need constructing.) */
5624 TYPE_NEEDS_CONSTRUCTING (t)
5625 |= (type_has_user_provided_constructor (t) || TYPE_CONTAINS_VPTR_P (t));
5626 /* [dcl.init.aggr]
5627
5628 An aggregate is an array or a class with no user-provided
5629 constructors ... and no virtual functions.
5630
5631 Again, other conditions for being an aggregate are checked
5632 elsewhere. */
5633 CLASSTYPE_NON_AGGREGATE (t)
5634 |= ((cxx_dialect < cxx2a
5635 ? type_has_user_provided_or_explicit_constructor (t)
5636 : TYPE_HAS_USER_CONSTRUCTOR (t))
5637 || TYPE_POLYMORPHIC_P (t));
5638 /* This is the C++98/03 definition of POD; it changed in C++0x, but we
5639 retain the old definition internally for ABI reasons. */
5640 CLASSTYPE_NON_LAYOUT_POD_P (t)
5641 |= (CLASSTYPE_NON_AGGREGATE (t)
5642 || saved_nontrivial_dtor || saved_complex_asn_ref);
5643 CLASSTYPE_NON_STD_LAYOUT (t) |= TYPE_CONTAINS_VPTR_P (t);
5644 TYPE_HAS_COMPLEX_COPY_ASSIGN (t) |= TYPE_CONTAINS_VPTR_P (t);
5645 TYPE_HAS_COMPLEX_MOVE_ASSIGN (t) |= TYPE_CONTAINS_VPTR_P (t);
5646 TYPE_HAS_COMPLEX_DFLT (t) |= TYPE_CONTAINS_VPTR_P (t);
5647
5648 /* If the only explicitly declared default constructor is user-provided,
5649 set TYPE_HAS_COMPLEX_DFLT. */
5650 if (!TYPE_HAS_COMPLEX_DFLT (t)
5651 && TYPE_HAS_DEFAULT_CONSTRUCTOR (t)
5652 && !type_has_non_user_provided_default_constructor (t))
5653 TYPE_HAS_COMPLEX_DFLT (t) = true;
5654
5655 /* Warn if a public base of a polymorphic type has an accessible
5656 non-virtual destructor. It is only now that we know the class is
5657 polymorphic. Although a polymorphic base will have a already
5658 been diagnosed during its definition, we warn on use too. */
5659 if (TYPE_POLYMORPHIC_P (t) && warn_nonvdtor)
5660 {
5661 tree binfo = TYPE_BINFO (t);
5662 vec<tree, va_gc> *accesses = BINFO_BASE_ACCESSES (binfo);
5663 tree base_binfo;
5664 unsigned i;
5665
5666 for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
5667 {
5668 tree basetype = TREE_TYPE (base_binfo);
5669
5670 if ((*accesses)[i] == access_public_node
5671 && (TYPE_POLYMORPHIC_P (basetype) || warn_ecpp)
5672 && accessible_nvdtor_p (basetype))
5673 warning (OPT_Wnon_virtual_dtor,
5674 "base class %q#T has accessible non-virtual destructor",
5675 basetype);
5676 }
5677 }
5678
5679 /* If the class has no user-declared constructor, but does have
5680 non-static const or reference data members that can never be
5681 initialized, issue a warning. */
5682 if (warn_uninitialized
5683 /* Classes with user-declared constructors are presumed to
5684 initialize these members. */
5685 && !TYPE_HAS_USER_CONSTRUCTOR (t)
5686 /* Aggregates can be initialized with brace-enclosed
5687 initializers. */
5688 && CLASSTYPE_NON_AGGREGATE (t))
5689 {
5690 tree field;
5691
5692 for (field = TYPE_FIELDS (t); field; field = DECL_CHAIN (field))
5693 {
5694 tree type;
5695
5696 if (TREE_CODE (field) != FIELD_DECL
5697 || DECL_INITIAL (field) != NULL_TREE)
5698 continue;
5699
5700 type = TREE_TYPE (field);
5701 if (TYPE_REF_P (type))
5702 warning_at (DECL_SOURCE_LOCATION (field),
5703 OPT_Wuninitialized, "non-static reference %q#D "
5704 "in class without a constructor", field);
5705 else if (CP_TYPE_CONST_P (type)
5706 && (!CLASS_TYPE_P (type)
5707 || !TYPE_HAS_DEFAULT_CONSTRUCTOR (type)))
5708 warning_at (DECL_SOURCE_LOCATION (field),
5709 OPT_Wuninitialized, "non-static const member %q#D "
5710 "in class without a constructor", field);
5711 }
5712 }
5713
5714 /* Synthesize any needed methods. */
5715 add_implicitly_declared_members (t, &access_decls,
5716 cant_have_const_ctor,
5717 no_const_asn_ref);
5718
5719 /* Check defaulted declarations here so we have cant_have_const_ctor
5720 and don't need to worry about clones. */
5721 for (fn = TYPE_FIELDS (t); fn; fn = DECL_CHAIN (fn))
5722 if (DECL_DECLARES_FUNCTION_P (fn)
5723 && !DECL_ARTIFICIAL (fn)
5724 && DECL_DEFAULTED_IN_CLASS_P (fn))
5725 {
5726 int copy = copy_fn_p (fn);
5727 if (copy > 0)
5728 {
5729 bool imp_const_p
5730 = (DECL_CONSTRUCTOR_P (fn) ? !cant_have_const_ctor
5731 : !no_const_asn_ref);
5732 bool fn_const_p = (copy == 2);
5733
5734 if (fn_const_p && !imp_const_p)
5735 /* If the function is defaulted outside the class, we just
5736 give the synthesis error. Core Issue #1331 says this is
5737 no longer ill-formed, it is defined as deleted instead. */
5738 DECL_DELETED_FN (fn) = true;
5739 }
5740 defaulted_late_check (fn);
5741 }
5742
5743 if (LAMBDA_TYPE_P (t))
5744 {
5745 /* "This class type is not an aggregate." */
5746 CLASSTYPE_NON_AGGREGATE (t) = 1;
5747 }
5748
5749 /* Compute the 'literal type' property before we
5750 do anything with non-static member functions. */
5751 finalize_literal_type_property (t);
5752
5753 /* Create the in-charge and not-in-charge variants of constructors
5754 and destructors. */
5755 clone_constructors_and_destructors (t);
5756
5757 /* Process the using-declarations. */
5758 for (; access_decls; access_decls = TREE_CHAIN (access_decls))
5759 handle_using_decl (TREE_VALUE (access_decls), t);
5760
5761 /* Figure out whether or not we will need a cookie when dynamically
5762 allocating an array of this type. */
5763 LANG_TYPE_CLASS_CHECK (t)->vec_new_uses_cookie
5764 = type_requires_array_cookie (t);
5765 }
5766
5767 /* If T needs a pointer to its virtual function table, set TYPE_VFIELD
5768 accordingly. If a new vfield was created (because T doesn't have a
5769 primary base class), then the newly created field is returned. It
5770 is not added to the TYPE_FIELDS list; it is the caller's
5771 responsibility to do that. Accumulate declared virtual functions
5772 on VIRTUALS_P. */
5773
5774 static tree
create_vtable_ptr(tree t,tree * virtuals_p)5775 create_vtable_ptr (tree t, tree* virtuals_p)
5776 {
5777 tree fn;
5778
5779 /* Collect the virtual functions declared in T. */
5780 for (fn = TYPE_FIELDS (t); fn; fn = DECL_CHAIN (fn))
5781 if (TREE_CODE (fn) == FUNCTION_DECL
5782 && DECL_VINDEX (fn) && !DECL_MAYBE_IN_CHARGE_DESTRUCTOR_P (fn)
5783 && TREE_CODE (DECL_VINDEX (fn)) != INTEGER_CST)
5784 {
5785 tree new_virtual = make_node (TREE_LIST);
5786
5787 BV_FN (new_virtual) = fn;
5788 BV_DELTA (new_virtual) = integer_zero_node;
5789 BV_VCALL_INDEX (new_virtual) = NULL_TREE;
5790
5791 TREE_CHAIN (new_virtual) = *virtuals_p;
5792 *virtuals_p = new_virtual;
5793 }
5794
5795 /* If we couldn't find an appropriate base class, create a new field
5796 here. Even if there weren't any new virtual functions, we might need a
5797 new virtual function table if we're supposed to include vptrs in
5798 all classes that need them. */
5799 if (!TYPE_VFIELD (t) && (*virtuals_p || TYPE_CONTAINS_VPTR_P (t)))
5800 {
5801 /* We build this decl with vtbl_ptr_type_node, which is a
5802 `vtable_entry_type*'. It might seem more precise to use
5803 `vtable_entry_type (*)[N]' where N is the number of virtual
5804 functions. However, that would require the vtable pointer in
5805 base classes to have a different type than the vtable pointer
5806 in derived classes. We could make that happen, but that
5807 still wouldn't solve all the problems. In particular, the
5808 type-based alias analysis code would decide that assignments
5809 to the base class vtable pointer can't alias assignments to
5810 the derived class vtable pointer, since they have different
5811 types. Thus, in a derived class destructor, where the base
5812 class constructor was inlined, we could generate bad code for
5813 setting up the vtable pointer.
5814
5815 Therefore, we use one type for all vtable pointers. We still
5816 use a type-correct type; it's just doesn't indicate the array
5817 bounds. That's better than using `void*' or some such; it's
5818 cleaner, and it let's the alias analysis code know that these
5819 stores cannot alias stores to void*! */
5820 tree field;
5821
5822 field = build_decl (input_location,
5823 FIELD_DECL, get_vfield_name (t), vtbl_ptr_type_node);
5824 DECL_VIRTUAL_P (field) = 1;
5825 DECL_ARTIFICIAL (field) = 1;
5826 DECL_FIELD_CONTEXT (field) = t;
5827 DECL_FCONTEXT (field) = t;
5828 if (TYPE_PACKED (t))
5829 DECL_PACKED (field) = 1;
5830
5831 TYPE_VFIELD (t) = field;
5832
5833 /* This class is non-empty. */
5834 CLASSTYPE_EMPTY_P (t) = 0;
5835
5836 return field;
5837 }
5838
5839 return NULL_TREE;
5840 }
5841
5842 /* Add OFFSET to all base types of BINFO which is a base in the
5843 hierarchy dominated by T.
5844
5845 OFFSET, which is a type offset, is number of bytes. */
5846
5847 static void
propagate_binfo_offsets(tree binfo,tree offset)5848 propagate_binfo_offsets (tree binfo, tree offset)
5849 {
5850 int i;
5851 tree primary_binfo;
5852 tree base_binfo;
5853
5854 /* Update BINFO's offset. */
5855 BINFO_OFFSET (binfo)
5856 = fold_convert (sizetype,
5857 size_binop (PLUS_EXPR,
5858 fold_convert (ssizetype, BINFO_OFFSET (binfo)),
5859 offset));
5860
5861 /* Find the primary base class. */
5862 primary_binfo = get_primary_binfo (binfo);
5863
5864 if (primary_binfo && BINFO_INHERITANCE_CHAIN (primary_binfo) == binfo)
5865 propagate_binfo_offsets (primary_binfo, offset);
5866
5867 /* Scan all of the bases, pushing the BINFO_OFFSET adjust
5868 downwards. */
5869 for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
5870 {
5871 /* Don't do the primary base twice. */
5872 if (base_binfo == primary_binfo)
5873 continue;
5874
5875 if (BINFO_VIRTUAL_P (base_binfo))
5876 continue;
5877
5878 propagate_binfo_offsets (base_binfo, offset);
5879 }
5880 }
5881
5882 /* Set BINFO_OFFSET for all of the virtual bases for RLI->T. Update
5883 TYPE_ALIGN and TYPE_SIZE for T. OFFSETS gives the location of
5884 empty subobjects of T. */
5885
5886 static void
layout_virtual_bases(record_layout_info rli,splay_tree offsets)5887 layout_virtual_bases (record_layout_info rli, splay_tree offsets)
5888 {
5889 tree vbase;
5890 tree t = rli->t;
5891 tree *next_field;
5892
5893 if (BINFO_N_BASE_BINFOS (TYPE_BINFO (t)) == 0)
5894 return;
5895
5896 /* Find the last field. The artificial fields created for virtual
5897 bases will go after the last extant field to date. */
5898 next_field = &TYPE_FIELDS (t);
5899 while (*next_field)
5900 next_field = &DECL_CHAIN (*next_field);
5901
5902 /* Go through the virtual bases, allocating space for each virtual
5903 base that is not already a primary base class. These are
5904 allocated in inheritance graph order. */
5905 for (vbase = TYPE_BINFO (t); vbase; vbase = TREE_CHAIN (vbase))
5906 {
5907 if (!BINFO_VIRTUAL_P (vbase))
5908 continue;
5909
5910 if (!BINFO_PRIMARY_P (vbase))
5911 {
5912 /* This virtual base is not a primary base of any class in the
5913 hierarchy, so we have to add space for it. */
5914 next_field = build_base_field (rli, vbase,
5915 offsets, next_field);
5916 }
5917 }
5918 }
5919
5920 /* Returns the offset of the byte just past the end of the base class
5921 BINFO. */
5922
5923 static tree
end_of_base(tree binfo)5924 end_of_base (tree binfo)
5925 {
5926 tree size;
5927
5928 if (!CLASSTYPE_AS_BASE (BINFO_TYPE (binfo)))
5929 size = TYPE_SIZE_UNIT (char_type_node);
5930 else if (is_empty_class (BINFO_TYPE (binfo)))
5931 /* An empty class has zero CLASSTYPE_SIZE_UNIT, but we need to
5932 allocate some space for it. It cannot have virtual bases, so
5933 TYPE_SIZE_UNIT is fine. */
5934 size = TYPE_SIZE_UNIT (BINFO_TYPE (binfo));
5935 else
5936 size = CLASSTYPE_SIZE_UNIT (BINFO_TYPE (binfo));
5937
5938 return size_binop (PLUS_EXPR, BINFO_OFFSET (binfo), size);
5939 }
5940
5941 /* Returns the offset of the byte just past the end of the base class or empty
5942 data member with the highest offset in T. If INCLUDE_VIRTUALS_P is zero,
5943 then only non-virtual bases are included. */
5944
5945 static tree
end_of_class(tree t,bool include_virtuals_p)5946 end_of_class (tree t, bool include_virtuals_p)
5947 {
5948 tree result = size_zero_node;
5949 vec<tree, va_gc> *vbases;
5950 tree binfo;
5951 tree base_binfo;
5952 tree offset;
5953 int i;
5954
5955 for (binfo = TYPE_BINFO (t), i = 0;
5956 BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
5957 {
5958 if (!include_virtuals_p
5959 && BINFO_VIRTUAL_P (base_binfo)
5960 && (!BINFO_PRIMARY_P (base_binfo)
5961 || BINFO_INHERITANCE_CHAIN (base_binfo) != TYPE_BINFO (t)))
5962 continue;
5963
5964 offset = end_of_base (base_binfo);
5965 if (tree_int_cst_lt (result, offset))
5966 result = offset;
5967 }
5968
5969 /* Also consider empty data members. */
5970 for (tree field = TYPE_FIELDS (t); field; field = DECL_CHAIN (field))
5971 if (TREE_CODE (field) == FIELD_DECL
5972 && !DECL_ARTIFICIAL (field)
5973 && field_poverlapping_p (field)
5974 && is_empty_class (TREE_TYPE (field)))
5975 {
5976 /* Update sizeof(C) to max (sizeof(C), offset(D)+sizeof(D)) */
5977 offset = size_binop (PLUS_EXPR, DECL_FIELD_OFFSET (field),
5978 TYPE_SIZE_UNIT (TREE_TYPE (field)));
5979 if (tree_int_cst_lt (result, offset))
5980 result = offset;
5981 }
5982
5983 if (include_virtuals_p)
5984 for (vbases = CLASSTYPE_VBASECLASSES (t), i = 0;
5985 vec_safe_iterate (vbases, i, &base_binfo); i++)
5986 {
5987 offset = end_of_base (base_binfo);
5988 if (tree_int_cst_lt (result, offset))
5989 result = offset;
5990 }
5991
5992 return result;
5993 }
5994
5995 /* Warn about bases of T that are inaccessible because they are
5996 ambiguous. For example:
5997
5998 struct S {};
5999 struct T : public S {};
6000 struct U : public S, public T {};
6001
6002 Here, `(S*) new U' is not allowed because there are two `S'
6003 subobjects of U. */
6004
6005 static void
warn_about_ambiguous_bases(tree t)6006 warn_about_ambiguous_bases (tree t)
6007 {
6008 int i;
6009 vec<tree, va_gc> *vbases;
6010 tree basetype;
6011 tree binfo;
6012 tree base_binfo;
6013
6014 /* If there are no repeated bases, nothing can be ambiguous. */
6015 if (!CLASSTYPE_REPEATED_BASE_P (t))
6016 return;
6017
6018 /* Check direct bases. */
6019 for (binfo = TYPE_BINFO (t), i = 0;
6020 BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
6021 {
6022 basetype = BINFO_TYPE (base_binfo);
6023
6024 if (!uniquely_derived_from_p (basetype, t))
6025 warning (0, "direct base %qT inaccessible in %qT due to ambiguity",
6026 basetype, t);
6027 }
6028
6029 /* Check for ambiguous virtual bases. */
6030 if (extra_warnings)
6031 for (vbases = CLASSTYPE_VBASECLASSES (t), i = 0;
6032 vec_safe_iterate (vbases, i, &binfo); i++)
6033 {
6034 basetype = BINFO_TYPE (binfo);
6035
6036 if (!uniquely_derived_from_p (basetype, t))
6037 warning (OPT_Wextra, "virtual base %qT inaccessible in %qT due "
6038 "to ambiguity", basetype, t);
6039 }
6040 }
6041
6042 /* Compare two INTEGER_CSTs K1 and K2. */
6043
6044 static int
splay_tree_compare_integer_csts(splay_tree_key k1,splay_tree_key k2)6045 splay_tree_compare_integer_csts (splay_tree_key k1, splay_tree_key k2)
6046 {
6047 return tree_int_cst_compare ((tree) k1, (tree) k2);
6048 }
6049
6050 /* Increase the size indicated in RLI to account for empty classes
6051 that are "off the end" of the class. */
6052
6053 static void
include_empty_classes(record_layout_info rli)6054 include_empty_classes (record_layout_info rli)
6055 {
6056 tree eoc;
6057 tree rli_size;
6058
6059 /* It might be the case that we grew the class to allocate a
6060 zero-sized base class. That won't be reflected in RLI, yet,
6061 because we are willing to overlay multiple bases at the same
6062 offset. However, now we need to make sure that RLI is big enough
6063 to reflect the entire class. */
6064 eoc = end_of_class (rli->t, CLASSTYPE_AS_BASE (rli->t) != NULL_TREE);
6065 rli_size = rli_size_unit_so_far (rli);
6066 if (TREE_CODE (rli_size) == INTEGER_CST
6067 && tree_int_cst_lt (rli_size, eoc))
6068 {
6069 /* The size should have been rounded to a whole byte. */
6070 gcc_assert (tree_int_cst_equal
6071 (rli->bitpos, round_down (rli->bitpos, BITS_PER_UNIT)));
6072 rli->bitpos
6073 = size_binop (PLUS_EXPR,
6074 rli->bitpos,
6075 size_binop (MULT_EXPR,
6076 fold_convert (bitsizetype,
6077 size_binop (MINUS_EXPR,
6078 eoc, rli_size)),
6079 bitsize_int (BITS_PER_UNIT)));
6080 normalize_rli (rli);
6081 }
6082 }
6083
6084 /* Calculate the TYPE_SIZE, TYPE_ALIGN, etc for T. Calculate
6085 BINFO_OFFSETs for all of the base-classes. Position the vtable
6086 pointer. Accumulate declared virtual functions on VIRTUALS_P. */
6087
6088 static void
layout_class_type(tree t,tree * virtuals_p)6089 layout_class_type (tree t, tree *virtuals_p)
6090 {
6091 tree non_static_data_members;
6092 tree field;
6093 tree vptr;
6094 record_layout_info rli;
6095 /* Maps offsets (represented as INTEGER_CSTs) to a TREE_LIST of
6096 types that appear at that offset. */
6097 splay_tree empty_base_offsets;
6098 /* True if the last field laid out was a bit-field. */
6099 bool last_field_was_bitfield = false;
6100 /* The location at which the next field should be inserted. */
6101 tree *next_field;
6102
6103 /* Keep track of the first non-static data member. */
6104 non_static_data_members = TYPE_FIELDS (t);
6105
6106 /* Start laying out the record. */
6107 rli = start_record_layout (t);
6108
6109 /* Mark all the primary bases in the hierarchy. */
6110 determine_primary_bases (t);
6111
6112 /* Create a pointer to our virtual function table. */
6113 vptr = create_vtable_ptr (t, virtuals_p);
6114
6115 /* The vptr is always the first thing in the class. */
6116 if (vptr)
6117 {
6118 DECL_CHAIN (vptr) = TYPE_FIELDS (t);
6119 TYPE_FIELDS (t) = vptr;
6120 next_field = &DECL_CHAIN (vptr);
6121 place_field (rli, vptr);
6122 }
6123 else
6124 next_field = &TYPE_FIELDS (t);
6125
6126 /* Build FIELD_DECLs for all of the non-virtual base-types. */
6127 empty_base_offsets = splay_tree_new (splay_tree_compare_integer_csts,
6128 NULL, NULL);
6129 build_base_fields (rli, empty_base_offsets, next_field);
6130
6131 /* Layout the non-static data members. */
6132 for (field = non_static_data_members; field; field = DECL_CHAIN (field))
6133 {
6134 tree type;
6135 tree padding;
6136
6137 /* We still pass things that aren't non-static data members to
6138 the back end, in case it wants to do something with them. */
6139 if (TREE_CODE (field) != FIELD_DECL)
6140 {
6141 place_field (rli, field);
6142 /* If the static data member has incomplete type, keep track
6143 of it so that it can be completed later. (The handling
6144 of pending statics in finish_record_layout is
6145 insufficient; consider:
6146
6147 struct S1;
6148 struct S2 { static S1 s1; };
6149
6150 At this point, finish_record_layout will be called, but
6151 S1 is still incomplete.) */
6152 if (VAR_P (field))
6153 {
6154 maybe_register_incomplete_var (field);
6155 /* The visibility of static data members is determined
6156 at their point of declaration, not their point of
6157 definition. */
6158 determine_visibility (field);
6159 }
6160 continue;
6161 }
6162
6163 type = TREE_TYPE (field);
6164 if (type == error_mark_node)
6165 continue;
6166
6167 padding = NULL_TREE;
6168
6169 bool might_overlap = field_poverlapping_p (field);
6170
6171 if (might_overlap && CLASS_TYPE_P (type)
6172 && (CLASSTYPE_NON_LAYOUT_POD_P (type) || CLASSTYPE_EMPTY_P (type)))
6173 {
6174 /* if D is a potentially-overlapping data member, update sizeof(C) to
6175 max (sizeof(C), offset(D)+max (nvsize(D), dsize(D))). */
6176 tree nvsize = CLASSTYPE_SIZE_UNIT (type);
6177 /* end_of_class doesn't always give dsize, but it does in the case of
6178 a class with virtual bases, which is when dsize > nvsize. */
6179 tree dsize = end_of_class (type, /*vbases*/true);
6180 if (tree_int_cst_le (dsize, nvsize))
6181 {
6182 DECL_SIZE_UNIT (field) = nvsize;
6183 DECL_SIZE (field) = CLASSTYPE_SIZE (type);
6184 }
6185 else
6186 {
6187 DECL_SIZE_UNIT (field) = dsize;
6188 DECL_SIZE (field) = bit_from_pos (dsize, bitsize_zero_node);
6189 }
6190 }
6191
6192 /* If this field is a bit-field whose width is greater than its
6193 type, then there are some special rules for allocating
6194 it. */
6195 if (DECL_C_BIT_FIELD (field)
6196 && tree_int_cst_lt (TYPE_SIZE (type), DECL_SIZE (field)))
6197 {
6198 bool was_unnamed_p = false;
6199 /* We must allocate the bits as if suitably aligned for the
6200 longest integer type that fits in this many bits. Then,
6201 we are supposed to use the left over bits as additional
6202 padding. */
6203
6204 /* Do not pick a type bigger than MAX_FIXED_MODE_SIZE. */
6205 tree limit = size_int (MAX_FIXED_MODE_SIZE);
6206 if (tree_int_cst_lt (DECL_SIZE (field), limit))
6207 limit = DECL_SIZE (field);
6208
6209 tree integer_type = integer_types[itk_char];
6210 for (unsigned itk = itk_char; itk != itk_none; itk++)
6211 if (tree next = integer_types[itk])
6212 {
6213 if (tree_int_cst_lt (limit, TYPE_SIZE (next)))
6214 /* Too big, so our current guess is what we want. */
6215 break;
6216 /* Not bigger than limit, ok */
6217 integer_type = next;
6218 }
6219
6220 /* Figure out how much additional padding is required. */
6221 if (TREE_CODE (t) == UNION_TYPE)
6222 /* In a union, the padding field must have the full width
6223 of the bit-field; all fields start at offset zero. */
6224 padding = DECL_SIZE (field);
6225 else
6226 padding = size_binop (MINUS_EXPR, DECL_SIZE (field),
6227 TYPE_SIZE (integer_type));
6228
6229 if (integer_zerop (padding))
6230 padding = NULL_TREE;
6231
6232 /* An unnamed bitfield does not normally affect the
6233 alignment of the containing class on a target where
6234 PCC_BITFIELD_TYPE_MATTERS. But, the C++ ABI does not
6235 make any exceptions for unnamed bitfields when the
6236 bitfields are longer than their types. Therefore, we
6237 temporarily give the field a name. */
6238 if (PCC_BITFIELD_TYPE_MATTERS && !DECL_NAME (field))
6239 {
6240 was_unnamed_p = true;
6241 DECL_NAME (field) = make_anon_name ();
6242 }
6243
6244 DECL_SIZE (field) = TYPE_SIZE (integer_type);
6245 SET_DECL_ALIGN (field, TYPE_ALIGN (integer_type));
6246 DECL_USER_ALIGN (field) = TYPE_USER_ALIGN (integer_type);
6247 layout_nonempty_base_or_field (rli, field, NULL_TREE,
6248 empty_base_offsets);
6249 if (was_unnamed_p)
6250 DECL_NAME (field) = NULL_TREE;
6251 /* Now that layout has been performed, set the size of the
6252 field to the size of its declared type; the rest of the
6253 field is effectively invisible. */
6254 DECL_SIZE (field) = TYPE_SIZE (type);
6255 /* We must also reset the DECL_MODE of the field. */
6256 SET_DECL_MODE (field, TYPE_MODE (type));
6257 }
6258 else if (might_overlap && is_empty_class (type))
6259 layout_empty_base_or_field (rli, field, empty_base_offsets);
6260 else
6261 layout_nonempty_base_or_field (rli, field, NULL_TREE,
6262 empty_base_offsets);
6263
6264 /* Remember the location of any empty classes in FIELD. */
6265 record_subobject_offsets (field, empty_base_offsets);
6266
6267 /* If a bit-field does not immediately follow another bit-field,
6268 and yet it starts in the middle of a byte, we have failed to
6269 comply with the ABI. */
6270 if (warn_abi
6271 && DECL_C_BIT_FIELD (field)
6272 /* The TREE_NO_WARNING flag gets set by Objective-C when
6273 laying out an Objective-C class. The ObjC ABI differs
6274 from the C++ ABI, and so we do not want a warning
6275 here. */
6276 && !TREE_NO_WARNING (field)
6277 && !last_field_was_bitfield
6278 && !integer_zerop (size_binop (TRUNC_MOD_EXPR,
6279 DECL_FIELD_BIT_OFFSET (field),
6280 bitsize_unit_node)))
6281 warning_at (DECL_SOURCE_LOCATION (field), OPT_Wabi,
6282 "offset of %qD is not ABI-compliant and may "
6283 "change in a future version of GCC", field);
6284
6285 /* The middle end uses the type of expressions to determine the
6286 possible range of expression values. In order to optimize
6287 "x.i > 7" to "false" for a 2-bit bitfield "i", the middle end
6288 must be made aware of the width of "i", via its type.
6289
6290 Because C++ does not have integer types of arbitrary width,
6291 we must (for the purposes of the front end) convert from the
6292 type assigned here to the declared type of the bitfield
6293 whenever a bitfield expression is used as an rvalue.
6294 Similarly, when assigning a value to a bitfield, the value
6295 must be converted to the type given the bitfield here. */
6296 if (DECL_C_BIT_FIELD (field))
6297 {
6298 unsigned HOST_WIDE_INT width;
6299 tree ftype = TREE_TYPE (field);
6300 width = tree_to_uhwi (DECL_SIZE (field));
6301 if (width != TYPE_PRECISION (ftype))
6302 {
6303 TREE_TYPE (field)
6304 = c_build_bitfield_integer_type (width,
6305 TYPE_UNSIGNED (ftype));
6306 TREE_TYPE (field)
6307 = cp_build_qualified_type (TREE_TYPE (field),
6308 cp_type_quals (ftype));
6309 }
6310 }
6311
6312 /* If we needed additional padding after this field, add it
6313 now. */
6314 if (padding)
6315 {
6316 tree padding_field;
6317
6318 padding_field = build_decl (input_location,
6319 FIELD_DECL,
6320 NULL_TREE,
6321 char_type_node);
6322 DECL_BIT_FIELD (padding_field) = 1;
6323 DECL_SIZE (padding_field) = padding;
6324 DECL_CONTEXT (padding_field) = t;
6325 DECL_ARTIFICIAL (padding_field) = 1;
6326 DECL_IGNORED_P (padding_field) = 1;
6327 DECL_PADDING_P (padding_field) = 1;
6328 layout_nonempty_base_or_field (rli, padding_field,
6329 NULL_TREE,
6330 empty_base_offsets);
6331 }
6332
6333 last_field_was_bitfield = DECL_C_BIT_FIELD (field);
6334 }
6335
6336 if (!integer_zerop (rli->bitpos))
6337 {
6338 /* Make sure that we are on a byte boundary so that the size of
6339 the class without virtual bases will always be a round number
6340 of bytes. */
6341 rli->bitpos = round_up_loc (input_location, rli->bitpos, BITS_PER_UNIT);
6342 normalize_rli (rli);
6343 }
6344
6345 /* Delete all zero-width bit-fields from the list of fields. Now
6346 that the type is laid out they are no longer important. */
6347 remove_zero_width_bit_fields (t);
6348
6349 if (CLASSTYPE_NON_LAYOUT_POD_P (t) || CLASSTYPE_EMPTY_P (t))
6350 {
6351 /* T needs a different layout as a base (eliding virtual bases
6352 or whatever). Create that version. */
6353 tree base_t = make_node (TREE_CODE (t));
6354
6355 /* If the ABI version is not at least two, and the last
6356 field was a bit-field, RLI may not be on a byte
6357 boundary. In particular, rli_size_unit_so_far might
6358 indicate the last complete byte, while rli_size_so_far
6359 indicates the total number of bits used. Therefore,
6360 rli_size_so_far, rather than rli_size_unit_so_far, is
6361 used to compute TYPE_SIZE_UNIT. */
6362 tree eoc = end_of_class (t, /*include_virtuals_p=*/0);
6363 TYPE_SIZE_UNIT (base_t)
6364 = size_binop (MAX_EXPR,
6365 fold_convert (sizetype,
6366 size_binop (CEIL_DIV_EXPR,
6367 rli_size_so_far (rli),
6368 bitsize_int (BITS_PER_UNIT))),
6369 eoc);
6370 TYPE_SIZE (base_t)
6371 = size_binop (MAX_EXPR,
6372 rli_size_so_far (rli),
6373 size_binop (MULT_EXPR,
6374 fold_convert (bitsizetype, eoc),
6375 bitsize_int (BITS_PER_UNIT)));
6376 SET_TYPE_ALIGN (base_t, rli->record_align);
6377 TYPE_USER_ALIGN (base_t) = TYPE_USER_ALIGN (t);
6378 TYPE_TYPELESS_STORAGE (base_t) = TYPE_TYPELESS_STORAGE (t);
6379
6380 /* Copy the non-static data members of T. This will include its
6381 direct non-virtual bases & vtable. */
6382 next_field = &TYPE_FIELDS (base_t);
6383 for (field = TYPE_FIELDS (t); field; field = DECL_CHAIN (field))
6384 if (TREE_CODE (field) == FIELD_DECL)
6385 {
6386 *next_field = copy_node (field);
6387 DECL_CONTEXT (*next_field) = base_t;
6388 next_field = &DECL_CHAIN (*next_field);
6389 }
6390 *next_field = NULL_TREE;
6391
6392 /* We use the base type for trivial assignments, and hence it
6393 needs a mode. */
6394 compute_record_mode (base_t);
6395
6396 TYPE_CONTEXT (base_t) = t;
6397
6398 /* Record the base version of the type. */
6399 CLASSTYPE_AS_BASE (t) = base_t;
6400 }
6401 else
6402 CLASSTYPE_AS_BASE (t) = t;
6403
6404 /* Every empty class contains an empty class. */
6405 if (CLASSTYPE_EMPTY_P (t))
6406 CLASSTYPE_CONTAINS_EMPTY_CLASS_P (t) = 1;
6407
6408 /* Set the TYPE_DECL for this type to contain the right
6409 value for DECL_OFFSET, so that we can use it as part
6410 of a COMPONENT_REF for multiple inheritance. */
6411 layout_decl (TYPE_MAIN_DECL (t), 0);
6412
6413 /* Now fix up any virtual base class types that we left lying
6414 around. We must get these done before we try to lay out the
6415 virtual function table. As a side-effect, this will remove the
6416 base subobject fields. */
6417 layout_virtual_bases (rli, empty_base_offsets);
6418
6419 /* Make sure that empty classes are reflected in RLI at this
6420 point. */
6421 include_empty_classes (rli);
6422
6423 /* Make sure not to create any structures with zero size. */
6424 if (integer_zerop (rli_size_unit_so_far (rli)) && CLASSTYPE_EMPTY_P (t))
6425 place_field (rli,
6426 build_decl (input_location,
6427 FIELD_DECL, NULL_TREE, char_type_node));
6428
6429 /* If this is a non-POD, declaring it packed makes a difference to how it
6430 can be used as a field; don't let finalize_record_size undo it. */
6431 if (TYPE_PACKED (t) && !layout_pod_type_p (t))
6432 rli->packed_maybe_necessary = true;
6433
6434 /* Let the back end lay out the type. */
6435 finish_record_layout (rli, /*free_p=*/true);
6436
6437 if (TYPE_SIZE_UNIT (t)
6438 && TREE_CODE (TYPE_SIZE_UNIT (t)) == INTEGER_CST
6439 && !TREE_OVERFLOW (TYPE_SIZE_UNIT (t))
6440 && !valid_constant_size_p (TYPE_SIZE_UNIT (t)))
6441 error ("size of type %qT is too large (%qE bytes)", t, TYPE_SIZE_UNIT (t));
6442
6443 /* Warn about bases that can't be talked about due to ambiguity. */
6444 warn_about_ambiguous_bases (t);
6445
6446 /* Now that we're done with layout, give the base fields the real types. */
6447 for (field = TYPE_FIELDS (t); field; field = DECL_CHAIN (field))
6448 if (DECL_ARTIFICIAL (field) && IS_FAKE_BASE_TYPE (TREE_TYPE (field)))
6449 TREE_TYPE (field) = TYPE_CONTEXT (TREE_TYPE (field));
6450
6451 /* Clean up. */
6452 splay_tree_delete (empty_base_offsets);
6453
6454 if (CLASSTYPE_EMPTY_P (t)
6455 && tree_int_cst_lt (sizeof_biggest_empty_class,
6456 TYPE_SIZE_UNIT (t)))
6457 sizeof_biggest_empty_class = TYPE_SIZE_UNIT (t);
6458 }
6459
6460 /* Determine the "key method" for the class type indicated by TYPE,
6461 and set CLASSTYPE_KEY_METHOD accordingly. */
6462
6463 void
determine_key_method(tree type)6464 determine_key_method (tree type)
6465 {
6466 tree method;
6467
6468 if (processing_template_decl
6469 || CLASSTYPE_TEMPLATE_INSTANTIATION (type)
6470 || CLASSTYPE_INTERFACE_KNOWN (type))
6471 return;
6472
6473 /* The key method is the first non-pure virtual function that is not
6474 inline at the point of class definition. On some targets the
6475 key function may not be inline; those targets should not call
6476 this function until the end of the translation unit. */
6477 for (method = TYPE_FIELDS (type); method; method = DECL_CHAIN (method))
6478 if (TREE_CODE (method) == FUNCTION_DECL
6479 && DECL_VINDEX (method) != NULL_TREE
6480 && ! DECL_DECLARED_INLINE_P (method)
6481 && ! DECL_PURE_VIRTUAL_P (method))
6482 {
6483 CLASSTYPE_KEY_METHOD (type) = method;
6484 break;
6485 }
6486
6487 return;
6488 }
6489
6490 /* Helper of find_flexarrays. Return true when FLD refers to a non-static
6491 class data member of non-zero size, otherwise false. */
6492
6493 static inline bool
field_nonempty_p(const_tree fld)6494 field_nonempty_p (const_tree fld)
6495 {
6496 if (TREE_CODE (fld) == ERROR_MARK)
6497 return false;
6498
6499 tree type = TREE_TYPE (fld);
6500 if (TREE_CODE (fld) == FIELD_DECL
6501 && TREE_CODE (type) != ERROR_MARK
6502 && (DECL_NAME (fld) || RECORD_OR_UNION_TYPE_P (type)))
6503 {
6504 return TYPE_SIZE (type)
6505 && (TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST
6506 || !tree_int_cst_equal (size_zero_node, TYPE_SIZE (type)));
6507 }
6508
6509 return false;
6510 }
6511
6512 /* Used by find_flexarrays and related functions. */
6513
6514 struct flexmems_t
6515 {
6516 /* The first flexible array member or non-zero array member found
6517 in the order of layout. */
6518 tree array;
6519 /* First non-static non-empty data member in the class or its bases. */
6520 tree first;
6521 /* The first non-static non-empty data member following either
6522 the flexible array member, if found, or the zero-length array member
6523 otherwise. AFTER[1] refers to the first such data member of a union
6524 of which the struct containing the flexible array member or zero-length
6525 array is a member, or NULL when no such union exists. This element is
6526 only used during searching, not for diagnosing problems. AFTER[0]
6527 refers to the first such data member that is not a member of such
6528 a union. */
6529 tree after[2];
6530
6531 /* Refers to a struct (not union) in which the struct of which the flexible
6532 array is member is defined. Used to diagnose strictly (according to C)
6533 invalid uses of the latter structs. */
6534 tree enclosing;
6535 };
6536
6537 /* Find either the first flexible array member or the first zero-length
6538 array, in that order of preference, among members of class T (but not
6539 its base classes), and set members of FMEM accordingly.
6540 BASE_P is true if T is a base class of another class.
6541 PUN is set to the outermost union in which the flexible array member
6542 (or zero-length array) is defined if one such union exists, otherwise
6543 to NULL.
6544 Similarly, PSTR is set to a data member of the outermost struct of
6545 which the flexible array is a member if one such struct exists,
6546 otherwise to NULL. */
6547
6548 static void
find_flexarrays(tree t,flexmems_t * fmem,bool base_p,tree pun,tree pstr)6549 find_flexarrays (tree t, flexmems_t *fmem, bool base_p,
6550 tree pun /* = NULL_TREE */,
6551 tree pstr /* = NULL_TREE */)
6552 {
6553 /* Set the "pointer" to the outermost enclosing union if not set
6554 yet and maintain it for the remainder of the recursion. */
6555 if (!pun && TREE_CODE (t) == UNION_TYPE)
6556 pun = t;
6557
6558 for (tree fld = TYPE_FIELDS (t); fld; fld = DECL_CHAIN (fld))
6559 {
6560 if (fld == error_mark_node)
6561 return;
6562
6563 /* Is FLD a typedef for an anonymous struct? */
6564
6565 /* FIXME: Note that typedefs (as well as arrays) need to be fully
6566 handled elsewhere so that errors like the following are detected
6567 as well:
6568 typedef struct { int i, a[], j; } S; // bug c++/72753
6569 S s [2]; // bug c++/68489
6570 */
6571 if (TREE_CODE (fld) == TYPE_DECL
6572 && DECL_IMPLICIT_TYPEDEF_P (fld)
6573 && CLASS_TYPE_P (TREE_TYPE (fld))
6574 && anon_aggrname_p (DECL_NAME (fld)))
6575 {
6576 /* Check the nested unnamed type referenced via a typedef
6577 independently of FMEM (since it's not a data member of
6578 the enclosing class). */
6579 check_flexarrays (TREE_TYPE (fld));
6580 continue;
6581 }
6582
6583 /* Skip anything that's GCC-generated or not a (non-static) data
6584 member. */
6585 if (DECL_ARTIFICIAL (fld) || TREE_CODE (fld) != FIELD_DECL)
6586 continue;
6587
6588 /* Type of the member. */
6589 tree fldtype = TREE_TYPE (fld);
6590 if (fldtype == error_mark_node)
6591 return;
6592
6593 /* Determine the type of the array element or object referenced
6594 by the member so that it can be checked for flexible array
6595 members if it hasn't been yet. */
6596 tree eltype = fldtype;
6597 while (TREE_CODE (eltype) == ARRAY_TYPE
6598 || INDIRECT_TYPE_P (eltype))
6599 eltype = TREE_TYPE (eltype);
6600
6601 if (RECORD_OR_UNION_TYPE_P (eltype))
6602 {
6603 if (fmem->array && !fmem->after[bool (pun)])
6604 {
6605 /* Once the member after the flexible array has been found
6606 we're done. */
6607 fmem->after[bool (pun)] = fld;
6608 break;
6609 }
6610
6611 if (eltype == fldtype || TYPE_UNNAMED_P (eltype))
6612 {
6613 /* Descend into the non-static member struct or union and try
6614 to find a flexible array member or zero-length array among
6615 its members. This is only necessary for anonymous types
6616 and types in whose context the current type T has not been
6617 defined (the latter must not be checked again because they
6618 are already in the process of being checked by one of the
6619 recursive calls). */
6620
6621 tree first = fmem->first;
6622 tree array = fmem->array;
6623
6624 /* If this member isn't anonymous and a prior non-flexible array
6625 member has been seen in one of the enclosing structs, clear
6626 the FIRST member since it doesn't contribute to the flexible
6627 array struct's members. */
6628 if (first && !array && !ANON_AGGR_TYPE_P (eltype))
6629 fmem->first = NULL_TREE;
6630
6631 find_flexarrays (eltype, fmem, false, pun,
6632 !pstr && TREE_CODE (t) == RECORD_TYPE ? fld : pstr);
6633
6634 if (fmem->array != array)
6635 continue;
6636
6637 if (first && !array && !ANON_AGGR_TYPE_P (eltype))
6638 {
6639 /* Restore the FIRST member reset above if no flexible
6640 array member has been found in this member's struct. */
6641 fmem->first = first;
6642 }
6643
6644 /* If the member struct contains the first flexible array
6645 member, or if this member is a base class, continue to
6646 the next member and avoid setting the FMEM->NEXT pointer
6647 to point to it. */
6648 if (base_p)
6649 continue;
6650 }
6651 }
6652
6653 if (field_nonempty_p (fld))
6654 {
6655 /* Remember the first non-static data member. */
6656 if (!fmem->first)
6657 fmem->first = fld;
6658
6659 /* Remember the first non-static data member after the flexible
6660 array member, if one has been found, or the zero-length array
6661 if it has been found. */
6662 if (fmem->array && !fmem->after[bool (pun)])
6663 fmem->after[bool (pun)] = fld;
6664 }
6665
6666 /* Skip non-arrays. */
6667 if (TREE_CODE (fldtype) != ARRAY_TYPE)
6668 continue;
6669
6670 /* Determine the upper bound of the array if it has one. */
6671 if (TYPE_DOMAIN (fldtype))
6672 {
6673 if (fmem->array)
6674 {
6675 /* Make a record of the zero-length array if either one
6676 such field or a flexible array member has been seen to
6677 handle the pathological and unlikely case of multiple
6678 such members. */
6679 if (!fmem->after[bool (pun)])
6680 fmem->after[bool (pun)] = fld;
6681 }
6682 else if (integer_all_onesp (TYPE_MAX_VALUE (TYPE_DOMAIN (fldtype))))
6683 {
6684 /* Remember the first zero-length array unless a flexible array
6685 member has already been seen. */
6686 fmem->array = fld;
6687 fmem->enclosing = pstr;
6688 }
6689 }
6690 else
6691 {
6692 /* Flexible array members have no upper bound. */
6693 if (fmem->array)
6694 {
6695 if (TYPE_DOMAIN (TREE_TYPE (fmem->array)))
6696 {
6697 /* Replace the zero-length array if it's been stored and
6698 reset the after pointer. */
6699 fmem->after[bool (pun)] = NULL_TREE;
6700 fmem->array = fld;
6701 fmem->enclosing = pstr;
6702 }
6703 else if (!fmem->after[bool (pun)])
6704 /* Make a record of another flexible array member. */
6705 fmem->after[bool (pun)] = fld;
6706 }
6707 else
6708 {
6709 fmem->array = fld;
6710 fmem->enclosing = pstr;
6711 }
6712 }
6713 }
6714 }
6715
6716 /* Diagnose a strictly (by the C standard) invalid use of a struct with
6717 a flexible array member (or the zero-length array extension). */
6718
6719 static void
diagnose_invalid_flexarray(const flexmems_t * fmem)6720 diagnose_invalid_flexarray (const flexmems_t *fmem)
6721 {
6722 if (fmem->array && fmem->enclosing)
6723 {
6724 auto_diagnostic_group d;
6725 if (pedwarn (location_of (fmem->enclosing), OPT_Wpedantic,
6726 TYPE_DOMAIN (TREE_TYPE (fmem->array))
6727 ? G_("invalid use of %q#T with a zero-size array "
6728 "in %q#D")
6729 : G_("invalid use of %q#T with a flexible array member "
6730 "in %q#T"),
6731 DECL_CONTEXT (fmem->array),
6732 DECL_CONTEXT (fmem->enclosing)))
6733 inform (DECL_SOURCE_LOCATION (fmem->array),
6734 "array member %q#D declared here", fmem->array);
6735 }
6736 }
6737
6738 /* Issue diagnostics for invalid flexible array members or zero-length
6739 arrays that are not the last elements of the containing class or its
6740 base classes or that are its sole members. */
6741
6742 static void
diagnose_flexarrays(tree t,const flexmems_t * fmem)6743 diagnose_flexarrays (tree t, const flexmems_t *fmem)
6744 {
6745 if (!fmem->array)
6746 return;
6747
6748 if (fmem->first && !fmem->after[0])
6749 {
6750 diagnose_invalid_flexarray (fmem);
6751 return;
6752 }
6753
6754 /* Has a diagnostic been issued? */
6755 bool diagd = false;
6756
6757 const char *msg = 0;
6758
6759 if (TYPE_DOMAIN (TREE_TYPE (fmem->array)))
6760 {
6761 if (fmem->after[0])
6762 msg = G_("zero-size array member %qD not at end of %q#T");
6763 else if (!fmem->first)
6764 msg = G_("zero-size array member %qD in an otherwise empty %q#T");
6765
6766 if (msg)
6767 {
6768 location_t loc = DECL_SOURCE_LOCATION (fmem->array);
6769
6770 auto_diagnostic_group d;
6771 if (pedwarn (loc, OPT_Wpedantic, msg, fmem->array, t))
6772 {
6773 inform (location_of (t), "in the definition of %q#T", t);
6774 diagd = true;
6775 }
6776 }
6777 }
6778 else
6779 {
6780 if (fmem->after[0])
6781 msg = G_("flexible array member %qD not at end of %q#T");
6782 else if (!fmem->first)
6783 msg = G_("flexible array member %qD in an otherwise empty %q#T");
6784
6785 if (msg)
6786 {
6787 location_t loc = DECL_SOURCE_LOCATION (fmem->array);
6788 diagd = true;
6789
6790 auto_diagnostic_group d;
6791 error_at (loc, msg, fmem->array, t);
6792
6793 /* In the unlikely event that the member following the flexible
6794 array member is declared in a different class, or the member
6795 overlaps another member of a common union, point to it.
6796 Otherwise it should be obvious. */
6797 if (fmem->after[0]
6798 && ((DECL_CONTEXT (fmem->after[0])
6799 != DECL_CONTEXT (fmem->array))))
6800 {
6801 inform (DECL_SOURCE_LOCATION (fmem->after[0]),
6802 "next member %q#D declared here",
6803 fmem->after[0]);
6804 inform (location_of (t), "in the definition of %q#T", t);
6805 }
6806 }
6807 }
6808
6809 if (!diagd && fmem->array && fmem->enclosing)
6810 diagnose_invalid_flexarray (fmem);
6811 }
6812
6813
6814 /* Recursively check to make sure that any flexible array or zero-length
6815 array members of class T or its bases are valid (i.e., not the sole
6816 non-static data member of T and, if one exists, that it is the last
6817 non-static data member of T and its base classes. FMEM is expected
6818 to be initially null and is used internally by recursive calls to
6819 the function. Issue the appropriate diagnostics for the array member
6820 that fails the checks. */
6821
6822 static void
check_flexarrays(tree t,flexmems_t * fmem,bool base_p)6823 check_flexarrays (tree t, flexmems_t *fmem /* = NULL */,
6824 bool base_p /* = false */)
6825 {
6826 /* Initialize the result of a search for flexible array and zero-length
6827 array members. Avoid doing any work if the most interesting FMEM data
6828 have already been populated. */
6829 flexmems_t flexmems = flexmems_t ();
6830 if (!fmem)
6831 fmem = &flexmems;
6832 else if (fmem->array && fmem->first && fmem->after[0])
6833 return;
6834
6835 tree fam = fmem->array;
6836
6837 /* Recursively check the primary base class first. */
6838 if (CLASSTYPE_HAS_PRIMARY_BASE_P (t))
6839 {
6840 tree basetype = BINFO_TYPE (CLASSTYPE_PRIMARY_BINFO (t));
6841 check_flexarrays (basetype, fmem, true);
6842 }
6843
6844 /* Recursively check the base classes. */
6845 int nbases = TYPE_BINFO (t) ? BINFO_N_BASE_BINFOS (TYPE_BINFO (t)) : 0;
6846 for (int i = 0; i < nbases; ++i)
6847 {
6848 tree base_binfo = BINFO_BASE_BINFO (TYPE_BINFO (t), i);
6849
6850 /* The primary base class was already checked above. */
6851 if (base_binfo == CLASSTYPE_PRIMARY_BINFO (t))
6852 continue;
6853
6854 /* Virtual base classes are at the end. */
6855 if (BINFO_VIRTUAL_P (base_binfo))
6856 continue;
6857
6858 /* Check the base class. */
6859 check_flexarrays (BINFO_TYPE (base_binfo), fmem, /*base_p=*/true);
6860 }
6861
6862 if (fmem == &flexmems)
6863 {
6864 /* Check virtual base classes only once per derived class.
6865 I.e., this check is not performed recursively for base
6866 classes. */
6867 int i;
6868 tree base_binfo;
6869 vec<tree, va_gc> *vbases;
6870 for (vbases = CLASSTYPE_VBASECLASSES (t), i = 0;
6871 vec_safe_iterate (vbases, i, &base_binfo); i++)
6872 {
6873 /* Check the virtual base class. */
6874 tree basetype = TREE_TYPE (base_binfo);
6875
6876 check_flexarrays (basetype, fmem, /*base_p=*/true);
6877 }
6878 }
6879
6880 /* Is the type unnamed (and therefore a member of it potentially
6881 an anonymous struct or union)? */
6882 bool maybe_anon_p = TYPE_UNNAMED_P (t);
6883
6884 /* Search the members of the current (possibly derived) class, skipping
6885 unnamed structs and unions since those could be anonymous. */
6886 if (fmem != &flexmems || !maybe_anon_p)
6887 find_flexarrays (t, fmem, base_p || fam != fmem->array);
6888
6889 if (fmem == &flexmems && !maybe_anon_p)
6890 {
6891 /* Issue diagnostics for invalid flexible and zero-length array
6892 members found in base classes or among the members of the current
6893 class. Ignore anonymous structs and unions whose members are
6894 considered to be members of the enclosing class and thus will
6895 be diagnosed when checking it. */
6896 diagnose_flexarrays (t, fmem);
6897 }
6898 }
6899
6900 /* Perform processing required when the definition of T (a class type)
6901 is complete. Diagnose invalid definitions of flexible array members
6902 and zero-size arrays. */
6903
6904 void
finish_struct_1(tree t)6905 finish_struct_1 (tree t)
6906 {
6907 tree x;
6908 /* A TREE_LIST. The TREE_VALUE of each node is a FUNCTION_DECL. */
6909 tree virtuals = NULL_TREE;
6910
6911 if (COMPLETE_TYPE_P (t))
6912 {
6913 gcc_assert (MAYBE_CLASS_TYPE_P (t));
6914 error ("redefinition of %q#T", t);
6915 popclass ();
6916 return;
6917 }
6918
6919 /* If this type was previously laid out as a forward reference,
6920 make sure we lay it out again. */
6921 TYPE_SIZE (t) = NULL_TREE;
6922 CLASSTYPE_PRIMARY_BINFO (t) = NULL_TREE;
6923
6924 /* Make assumptions about the class; we'll reset the flags if
6925 necessary. */
6926 CLASSTYPE_EMPTY_P (t) = 1;
6927 CLASSTYPE_NEARLY_EMPTY_P (t) = 1;
6928 CLASSTYPE_CONTAINS_EMPTY_CLASS_P (t) = 0;
6929 CLASSTYPE_LITERAL_P (t) = true;
6930
6931 /* Do end-of-class semantic processing: checking the validity of the
6932 bases and members and add implicitly generated methods. */
6933 check_bases_and_members (t);
6934
6935 /* Find the key method. */
6936 if (TYPE_CONTAINS_VPTR_P (t))
6937 {
6938 /* The Itanium C++ ABI permits the key method to be chosen when
6939 the class is defined -- even though the key method so
6940 selected may later turn out to be an inline function. On
6941 some systems (such as ARM Symbian OS) the key method cannot
6942 be determined until the end of the translation unit. On such
6943 systems, we leave CLASSTYPE_KEY_METHOD set to NULL, which
6944 will cause the class to be added to KEYED_CLASSES. Then, in
6945 finish_file we will determine the key method. */
6946 if (targetm.cxx.key_method_may_be_inline ())
6947 determine_key_method (t);
6948
6949 /* If a polymorphic class has no key method, we may emit the vtable
6950 in every translation unit where the class definition appears. If
6951 we're devirtualizing, we can look into the vtable even if we
6952 aren't emitting it. */
6953 if (!CLASSTYPE_KEY_METHOD (t))
6954 vec_safe_push (keyed_classes, t);
6955 }
6956
6957 /* Layout the class itself. */
6958 layout_class_type (t, &virtuals);
6959 /* COMPLETE_TYPE_P is now true. */
6960
6961 set_class_bindings (t);
6962
6963 /* With the layout complete, check for flexible array members and
6964 zero-length arrays that might overlap other members in the final
6965 layout. */
6966 check_flexarrays (t);
6967
6968 virtuals = modify_all_vtables (t, nreverse (virtuals));
6969
6970 /* If necessary, create the primary vtable for this class. */
6971 if (virtuals || TYPE_CONTAINS_VPTR_P (t))
6972 {
6973 /* We must enter these virtuals into the table. */
6974 if (!CLASSTYPE_HAS_PRIMARY_BASE_P (t))
6975 build_primary_vtable (NULL_TREE, t);
6976 else if (! BINFO_NEW_VTABLE_MARKED (TYPE_BINFO (t)))
6977 /* Here we know enough to change the type of our virtual
6978 function table, but we will wait until later this function. */
6979 build_primary_vtable (CLASSTYPE_PRIMARY_BINFO (t), t);
6980
6981 /* If we're warning about ABI tags, check the types of the new
6982 virtual functions. */
6983 if (warn_abi_tag)
6984 for (tree v = virtuals; v; v = TREE_CHAIN (v))
6985 check_abi_tags (t, TREE_VALUE (v));
6986 }
6987
6988 if (TYPE_CONTAINS_VPTR_P (t))
6989 {
6990 int vindex;
6991 tree fn;
6992
6993 if (BINFO_VTABLE (TYPE_BINFO (t)))
6994 gcc_assert (DECL_VIRTUAL_P (BINFO_VTABLE (TYPE_BINFO (t))));
6995 if (!CLASSTYPE_HAS_PRIMARY_BASE_P (t))
6996 gcc_assert (BINFO_VIRTUALS (TYPE_BINFO (t)) == NULL_TREE);
6997
6998 /* Add entries for virtual functions introduced by this class. */
6999 BINFO_VIRTUALS (TYPE_BINFO (t))
7000 = chainon (BINFO_VIRTUALS (TYPE_BINFO (t)), virtuals);
7001
7002 /* Set DECL_VINDEX for all functions declared in this class. */
7003 for (vindex = 0, fn = BINFO_VIRTUALS (TYPE_BINFO (t));
7004 fn;
7005 fn = TREE_CHAIN (fn),
7006 vindex += (TARGET_VTABLE_USES_DESCRIPTORS
7007 ? TARGET_VTABLE_USES_DESCRIPTORS : 1))
7008 {
7009 tree fndecl = BV_FN (fn);
7010
7011 if (DECL_THUNK_P (fndecl))
7012 /* A thunk. We should never be calling this entry directly
7013 from this vtable -- we'd use the entry for the non
7014 thunk base function. */
7015 DECL_VINDEX (fndecl) = NULL_TREE;
7016 else if (TREE_CODE (DECL_VINDEX (fndecl)) != INTEGER_CST)
7017 DECL_VINDEX (fndecl) = build_int_cst (NULL_TREE, vindex);
7018 }
7019 }
7020
7021 finish_struct_bits (t);
7022
7023 set_method_tm_attributes (t);
7024 if (flag_openmp || flag_openmp_simd)
7025 finish_omp_declare_simd_methods (t);
7026
7027 /* Clear DECL_IN_AGGR_P for all member functions. Complete the rtl
7028 for any static member objects of the type we're working on. */
7029 for (x = TYPE_FIELDS (t); x; x = DECL_CHAIN (x))
7030 if (DECL_DECLARES_FUNCTION_P (x))
7031 DECL_IN_AGGR_P (x) = false;
7032 else if (VAR_P (x) && TREE_STATIC (x)
7033 && TREE_TYPE (x) != error_mark_node
7034 && same_type_p (TYPE_MAIN_VARIANT (TREE_TYPE (x)), t))
7035 SET_DECL_MODE (x, TYPE_MODE (t));
7036
7037 /* Complain if one of the field types requires lower visibility. */
7038 constrain_class_visibility (t);
7039
7040 /* Make the rtl for any new vtables we have created, and unmark
7041 the base types we marked. */
7042 finish_vtbls (t);
7043
7044 /* Build the VTT for T. */
7045 build_vtt (t);
7046
7047 if (warn_nonvdtor
7048 && TYPE_POLYMORPHIC_P (t) && accessible_nvdtor_p (t)
7049 && !CLASSTYPE_FINAL (t))
7050 warning (OPT_Wnon_virtual_dtor,
7051 "%q#T has virtual functions and accessible"
7052 " non-virtual destructor", t);
7053
7054 complete_vars (t);
7055
7056 if (warn_overloaded_virtual)
7057 warn_hidden (t);
7058
7059 /* Class layout, assignment of virtual table slots, etc., is now
7060 complete. Give the back end a chance to tweak the visibility of
7061 the class or perform any other required target modifications. */
7062 targetm.cxx.adjust_class_at_definition (t);
7063
7064 maybe_suppress_debug_info (t);
7065
7066 if (flag_vtable_verify)
7067 vtv_save_class_info (t);
7068
7069 dump_class_hierarchy (t);
7070
7071 /* Finish debugging output for this type. */
7072 rest_of_type_compilation (t, ! LOCAL_CLASS_P (t));
7073
7074 if (TYPE_TRANSPARENT_AGGR (t))
7075 {
7076 tree field = first_field (t);
7077 if (field == NULL_TREE || error_operand_p (field))
7078 {
7079 error ("type transparent %q#T does not have any fields", t);
7080 TYPE_TRANSPARENT_AGGR (t) = 0;
7081 }
7082 else if (DECL_ARTIFICIAL (field))
7083 {
7084 if (DECL_FIELD_IS_BASE (field))
7085 error ("type transparent class %qT has base classes", t);
7086 else
7087 {
7088 gcc_checking_assert (DECL_VIRTUAL_P (field));
7089 error ("type transparent class %qT has virtual functions", t);
7090 }
7091 TYPE_TRANSPARENT_AGGR (t) = 0;
7092 }
7093 else if (TYPE_MODE (t) != DECL_MODE (field))
7094 {
7095 error ("type transparent %q#T cannot be made transparent because "
7096 "the type of the first field has a different ABI from the "
7097 "class overall", t);
7098 TYPE_TRANSPARENT_AGGR (t) = 0;
7099 }
7100 }
7101 }
7102
7103 /* When T was built up, the member declarations were added in reverse
7104 order. Rearrange them to declaration order. */
7105
7106 void
unreverse_member_declarations(tree t)7107 unreverse_member_declarations (tree t)
7108 {
7109 tree next;
7110 tree prev;
7111 tree x;
7112
7113 /* The following lists are all in reverse order. Put them in
7114 declaration order now. */
7115 CLASSTYPE_DECL_LIST (t) = nreverse (CLASSTYPE_DECL_LIST (t));
7116
7117 /* For the TYPE_FIELDS, only the non TYPE_DECLs are in reverse
7118 order, so we can't just use nreverse. Due to stat_hack
7119 chicanery in finish_member_declaration. */
7120 prev = NULL_TREE;
7121 for (x = TYPE_FIELDS (t);
7122 x && TREE_CODE (x) != TYPE_DECL;
7123 x = next)
7124 {
7125 next = DECL_CHAIN (x);
7126 DECL_CHAIN (x) = prev;
7127 prev = x;
7128 }
7129
7130 if (prev)
7131 {
7132 DECL_CHAIN (TYPE_FIELDS (t)) = x;
7133 TYPE_FIELDS (t) = prev;
7134 }
7135 }
7136
7137 tree
finish_struct(tree t,tree attributes)7138 finish_struct (tree t, tree attributes)
7139 {
7140 location_t saved_loc = input_location;
7141
7142 /* Now that we've got all the field declarations, reverse everything
7143 as necessary. */
7144 unreverse_member_declarations (t);
7145
7146 cplus_decl_attributes (&t, attributes, (int) ATTR_FLAG_TYPE_IN_PLACE);
7147 fixup_attribute_variants (t);
7148
7149 /* Nadger the current location so that diagnostics point to the start of
7150 the struct, not the end. */
7151 input_location = DECL_SOURCE_LOCATION (TYPE_NAME (t));
7152
7153 if (processing_template_decl)
7154 {
7155 tree x;
7156
7157 /* We need to add the target functions of USING_DECLS, so that
7158 they can be found when the using declaration is not
7159 instantiated yet. */
7160 for (x = TYPE_FIELDS (t); x; x = DECL_CHAIN (x))
7161 if (TREE_CODE (x) == USING_DECL)
7162 {
7163 tree fn = strip_using_decl (x);
7164 if (OVL_P (fn))
7165 for (lkp_iterator iter (fn); iter; ++iter)
7166 add_method (t, *iter, true);
7167 }
7168 else if (DECL_DECLARES_FUNCTION_P (x))
7169 DECL_IN_AGGR_P (x) = false;
7170
7171 /* Also add a USING_DECL for operator=. We know there'll be (at
7172 least) one, but we don't know the signature(s). We want name
7173 lookup not to fail or recurse into bases. This isn't added
7174 to the template decl list so we drop this at instantiation
7175 time. */
7176 tree ass_op = build_lang_decl (USING_DECL, assign_op_identifier,
7177 NULL_TREE);
7178 DECL_CONTEXT (ass_op) = t;
7179 USING_DECL_SCOPE (ass_op) = t;
7180 DECL_DEPENDENT_P (ass_op) = true;
7181 DECL_ARTIFICIAL (ass_op) = true;
7182 DECL_CHAIN (ass_op) = TYPE_FIELDS (t);
7183 TYPE_FIELDS (t) = ass_op;
7184
7185 TYPE_SIZE (t) = bitsize_zero_node;
7186 TYPE_SIZE_UNIT (t) = size_zero_node;
7187 /* COMPLETE_TYPE_P is now true. */
7188
7189 set_class_bindings (t);
7190
7191 /* We need to emit an error message if this type was used as a parameter
7192 and it is an abstract type, even if it is a template. We construct
7193 a simple CLASSTYPE_PURE_VIRTUALS list without taking bases into
7194 account and we call complete_vars with this type, which will check
7195 the PARM_DECLS. Note that while the type is being defined,
7196 CLASSTYPE_PURE_VIRTUALS contains the list of the inline friends
7197 (see CLASSTYPE_INLINE_FRIENDS) so we need to clear it. */
7198 CLASSTYPE_PURE_VIRTUALS (t) = NULL;
7199 for (x = TYPE_FIELDS (t); x; x = DECL_CHAIN (x))
7200 if (TREE_CODE (x) == FUNCTION_DECL && DECL_PURE_VIRTUAL_P (x))
7201 vec_safe_push (CLASSTYPE_PURE_VIRTUALS (t), x);
7202 complete_vars (t);
7203
7204 /* Remember current #pragma pack value. */
7205 TYPE_PRECISION (t) = maximum_field_alignment;
7206
7207 /* Fix up any variants we've already built. */
7208 for (x = TYPE_NEXT_VARIANT (t); x; x = TYPE_NEXT_VARIANT (x))
7209 {
7210 TYPE_SIZE (x) = TYPE_SIZE (t);
7211 TYPE_SIZE_UNIT (x) = TYPE_SIZE_UNIT (t);
7212 TYPE_FIELDS (x) = TYPE_FIELDS (t);
7213 }
7214 }
7215 else
7216 finish_struct_1 (t);
7217 /* COMPLETE_TYPE_P is now true. */
7218
7219 maybe_warn_about_overly_private_class (t);
7220
7221 if (is_std_init_list (t))
7222 {
7223 /* People keep complaining that the compiler crashes on an invalid
7224 definition of initializer_list, so I guess we should explicitly
7225 reject it. What the compiler internals care about is that it's a
7226 template and has a pointer field followed by size_type field. */
7227 bool ok = false;
7228 if (processing_template_decl)
7229 {
7230 tree f = next_initializable_field (TYPE_FIELDS (t));
7231 if (f && TYPE_PTR_P (TREE_TYPE (f)))
7232 {
7233 f = next_initializable_field (DECL_CHAIN (f));
7234 if (f && same_type_p (TREE_TYPE (f), size_type_node))
7235 ok = true;
7236 }
7237 }
7238 if (!ok)
7239 fatal_error (input_location, "definition of %qD does not match "
7240 "%<#include <initializer_list>%>", TYPE_NAME (t));
7241 }
7242
7243 input_location = saved_loc;
7244
7245 TYPE_BEING_DEFINED (t) = 0;
7246
7247 if (current_class_type)
7248 popclass ();
7249 else
7250 error ("trying to finish struct, but kicked out due to previous parse errors");
7251
7252 if (processing_template_decl && at_function_scope_p ()
7253 /* Lambdas are defined by the LAMBDA_EXPR. */
7254 && !LAMBDA_TYPE_P (t))
7255 add_stmt (build_min (TAG_DEFN, t));
7256
7257 return t;
7258 }
7259
7260 /* Hash table to avoid endless recursion when handling references. */
7261 static hash_table<nofree_ptr_hash<tree_node> > *fixed_type_or_null_ref_ht;
7262
7263 /* Return the dynamic type of INSTANCE, if known.
7264 Used to determine whether the virtual function table is needed
7265 or not.
7266
7267 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
7268 of our knowledge of its type. *NONNULL should be initialized
7269 before this function is called. */
7270
7271 static tree
fixed_type_or_null(tree instance,int * nonnull,int * cdtorp)7272 fixed_type_or_null (tree instance, int *nonnull, int *cdtorp)
7273 {
7274 #define RECUR(T) fixed_type_or_null((T), nonnull, cdtorp)
7275
7276 switch (TREE_CODE (instance))
7277 {
7278 case INDIRECT_REF:
7279 if (INDIRECT_TYPE_P (TREE_TYPE (instance)))
7280 return NULL_TREE;
7281 else
7282 return RECUR (TREE_OPERAND (instance, 0));
7283
7284 case CALL_EXPR:
7285 /* This is a call to a constructor, hence it's never zero. */
7286 if (CALL_EXPR_FN (instance)
7287 && TREE_HAS_CONSTRUCTOR (instance))
7288 {
7289 if (nonnull)
7290 *nonnull = 1;
7291 return TREE_TYPE (instance);
7292 }
7293 return NULL_TREE;
7294
7295 case SAVE_EXPR:
7296 /* This is a call to a constructor, hence it's never zero. */
7297 if (TREE_HAS_CONSTRUCTOR (instance))
7298 {
7299 if (nonnull)
7300 *nonnull = 1;
7301 return TREE_TYPE (instance);
7302 }
7303 return RECUR (TREE_OPERAND (instance, 0));
7304
7305 case POINTER_PLUS_EXPR:
7306 case PLUS_EXPR:
7307 case MINUS_EXPR:
7308 if (TREE_CODE (TREE_OPERAND (instance, 0)) == ADDR_EXPR)
7309 return RECUR (TREE_OPERAND (instance, 0));
7310 if (TREE_CODE (TREE_OPERAND (instance, 1)) == INTEGER_CST)
7311 /* Propagate nonnull. */
7312 return RECUR (TREE_OPERAND (instance, 0));
7313
7314 return NULL_TREE;
7315
7316 CASE_CONVERT:
7317 return RECUR (TREE_OPERAND (instance, 0));
7318
7319 case ADDR_EXPR:
7320 instance = TREE_OPERAND (instance, 0);
7321 if (nonnull)
7322 {
7323 /* Just because we see an ADDR_EXPR doesn't mean we're dealing
7324 with a real object -- given &p->f, p can still be null. */
7325 tree t = get_base_address (instance);
7326 /* ??? Probably should check DECL_WEAK here. */
7327 if (t && DECL_P (t))
7328 *nonnull = 1;
7329 }
7330 return RECUR (instance);
7331
7332 case COMPONENT_REF:
7333 /* If this component is really a base class reference, then the field
7334 itself isn't definitive. */
7335 if (DECL_FIELD_IS_BASE (TREE_OPERAND (instance, 1)))
7336 return RECUR (TREE_OPERAND (instance, 0));
7337 return RECUR (TREE_OPERAND (instance, 1));
7338
7339 case VAR_DECL:
7340 case FIELD_DECL:
7341 if (TREE_CODE (TREE_TYPE (instance)) == ARRAY_TYPE
7342 && MAYBE_CLASS_TYPE_P (TREE_TYPE (TREE_TYPE (instance))))
7343 {
7344 if (nonnull)
7345 *nonnull = 1;
7346 return TREE_TYPE (TREE_TYPE (instance));
7347 }
7348 /* fall through. */
7349 case TARGET_EXPR:
7350 case PARM_DECL:
7351 case RESULT_DECL:
7352 if (MAYBE_CLASS_TYPE_P (TREE_TYPE (instance)))
7353 {
7354 if (nonnull)
7355 *nonnull = 1;
7356 return TREE_TYPE (instance);
7357 }
7358 else if (instance == current_class_ptr)
7359 {
7360 if (nonnull)
7361 *nonnull = 1;
7362
7363 /* if we're in a ctor or dtor, we know our type. If
7364 current_class_ptr is set but we aren't in a function, we're in
7365 an NSDMI (and therefore a constructor). */
7366 if (current_scope () != current_function_decl
7367 || (DECL_LANG_SPECIFIC (current_function_decl)
7368 && (DECL_CONSTRUCTOR_P (current_function_decl)
7369 || DECL_DESTRUCTOR_P (current_function_decl))))
7370 {
7371 if (cdtorp)
7372 *cdtorp = 1;
7373 return TREE_TYPE (TREE_TYPE (instance));
7374 }
7375 }
7376 else if (TYPE_REF_P (TREE_TYPE (instance)))
7377 {
7378 /* We only need one hash table because it is always left empty. */
7379 if (!fixed_type_or_null_ref_ht)
7380 fixed_type_or_null_ref_ht
7381 = new hash_table<nofree_ptr_hash<tree_node> > (37);
7382
7383 /* Reference variables should be references to objects. */
7384 if (nonnull)
7385 *nonnull = 1;
7386
7387 /* Enter the INSTANCE in a table to prevent recursion; a
7388 variable's initializer may refer to the variable
7389 itself. */
7390 if (VAR_P (instance)
7391 && DECL_INITIAL (instance)
7392 && !type_dependent_expression_p_push (DECL_INITIAL (instance))
7393 && !fixed_type_or_null_ref_ht->find (instance))
7394 {
7395 tree type;
7396 tree_node **slot;
7397
7398 slot = fixed_type_or_null_ref_ht->find_slot (instance, INSERT);
7399 *slot = instance;
7400 type = RECUR (DECL_INITIAL (instance));
7401 fixed_type_or_null_ref_ht->remove_elt (instance);
7402
7403 return type;
7404 }
7405 }
7406 return NULL_TREE;
7407
7408 case VIEW_CONVERT_EXPR:
7409 if (location_wrapper_p (instance))
7410 return RECUR (TREE_OPERAND (instance, 0));
7411 else
7412 /* TODO: Recursion may be correct for some non-location-wrapper
7413 uses of VIEW_CONVERT_EXPR. */
7414 return NULL_TREE;
7415
7416 default:
7417 return NULL_TREE;
7418 }
7419 #undef RECUR
7420 }
7421
7422 /* Return nonzero if the dynamic type of INSTANCE is known, and
7423 equivalent to the static type. We also handle the case where
7424 INSTANCE is really a pointer. Return negative if this is a
7425 ctor/dtor. There the dynamic type is known, but this might not be
7426 the most derived base of the original object, and hence virtual
7427 bases may not be laid out according to this type.
7428
7429 Used to determine whether the virtual function table is needed
7430 or not.
7431
7432 *NONNULL is set iff INSTANCE can be known to be nonnull, regardless
7433 of our knowledge of its type. *NONNULL should be initialized
7434 before this function is called. */
7435
7436 int
resolves_to_fixed_type_p(tree instance,int * nonnull)7437 resolves_to_fixed_type_p (tree instance, int* nonnull)
7438 {
7439 tree t = TREE_TYPE (instance);
7440 int cdtorp = 0;
7441 tree fixed;
7442
7443 /* processing_template_decl can be false in a template if we're in
7444 instantiate_non_dependent_expr, but we still want to suppress
7445 this check. */
7446 if (in_template_function ())
7447 {
7448 /* In a template we only care about the type of the result. */
7449 if (nonnull)
7450 *nonnull = true;
7451 return true;
7452 }
7453
7454 fixed = fixed_type_or_null (instance, nonnull, &cdtorp);
7455 if (fixed == NULL_TREE)
7456 return 0;
7457 if (INDIRECT_TYPE_P (t))
7458 t = TREE_TYPE (t);
7459 if (!same_type_ignoring_top_level_qualifiers_p (t, fixed))
7460 return 0;
7461 return cdtorp ? -1 : 1;
7462 }
7463
7464
7465 void
init_class_processing(void)7466 init_class_processing (void)
7467 {
7468 current_class_depth = 0;
7469 current_class_stack_size = 10;
7470 current_class_stack
7471 = XNEWVEC (struct class_stack_node, current_class_stack_size);
7472 sizeof_biggest_empty_class = size_zero_node;
7473
7474 ridpointers[(int) RID_PUBLIC] = access_public_node;
7475 ridpointers[(int) RID_PRIVATE] = access_private_node;
7476 ridpointers[(int) RID_PROTECTED] = access_protected_node;
7477 }
7478
7479 /* Restore the cached PREVIOUS_CLASS_LEVEL. */
7480
7481 static void
restore_class_cache(void)7482 restore_class_cache (void)
7483 {
7484 tree type;
7485
7486 /* We are re-entering the same class we just left, so we don't
7487 have to search the whole inheritance matrix to find all the
7488 decls to bind again. Instead, we install the cached
7489 class_shadowed list and walk through it binding names. */
7490 push_binding_level (previous_class_level);
7491 class_binding_level = previous_class_level;
7492 /* Restore IDENTIFIER_TYPE_VALUE. */
7493 for (type = class_binding_level->type_shadowed;
7494 type;
7495 type = TREE_CHAIN (type))
7496 SET_IDENTIFIER_TYPE_VALUE (TREE_PURPOSE (type), TREE_TYPE (type));
7497 }
7498
7499 /* Set global variables CURRENT_CLASS_NAME and CURRENT_CLASS_TYPE as
7500 appropriate for TYPE.
7501
7502 So that we may avoid calls to lookup_name, we cache the _TYPE
7503 nodes of local TYPE_DECLs in the TREE_TYPE field of the name.
7504
7505 For multiple inheritance, we perform a two-pass depth-first search
7506 of the type lattice. */
7507
7508 void
pushclass(tree type)7509 pushclass (tree type)
7510 {
7511 class_stack_node_t csn;
7512
7513 type = TYPE_MAIN_VARIANT (type);
7514
7515 /* Make sure there is enough room for the new entry on the stack. */
7516 if (current_class_depth + 1 >= current_class_stack_size)
7517 {
7518 current_class_stack_size *= 2;
7519 current_class_stack
7520 = XRESIZEVEC (struct class_stack_node, current_class_stack,
7521 current_class_stack_size);
7522 }
7523
7524 /* Insert a new entry on the class stack. */
7525 csn = current_class_stack + current_class_depth;
7526 csn->name = current_class_name;
7527 csn->type = current_class_type;
7528 csn->access = current_access_specifier;
7529 csn->names_used = 0;
7530 csn->hidden = 0;
7531 current_class_depth++;
7532
7533 /* Now set up the new type. */
7534 current_class_name = TYPE_NAME (type);
7535 if (TREE_CODE (current_class_name) == TYPE_DECL)
7536 current_class_name = DECL_NAME (current_class_name);
7537 current_class_type = type;
7538
7539 /* By default, things in classes are private, while things in
7540 structures or unions are public. */
7541 current_access_specifier = (CLASSTYPE_DECLARED_CLASS (type)
7542 ? access_private_node
7543 : access_public_node);
7544
7545 if (previous_class_level
7546 && type != previous_class_level->this_entity
7547 && current_class_depth == 1)
7548 {
7549 /* Forcibly remove any old class remnants. */
7550 invalidate_class_lookup_cache ();
7551 }
7552
7553 if (!previous_class_level
7554 || type != previous_class_level->this_entity
7555 || current_class_depth > 1)
7556 pushlevel_class ();
7557 else
7558 restore_class_cache ();
7559 }
7560
7561 /* When we exit a toplevel class scope, we save its binding level so
7562 that we can restore it quickly. Here, we've entered some other
7563 class, so we must invalidate our cache. */
7564
7565 void
invalidate_class_lookup_cache(void)7566 invalidate_class_lookup_cache (void)
7567 {
7568 previous_class_level = NULL;
7569 }
7570
7571 /* Get out of the current class scope. If we were in a class scope
7572 previously, that is the one popped to. */
7573
7574 void
popclass(void)7575 popclass (void)
7576 {
7577 poplevel_class ();
7578
7579 current_class_depth--;
7580 current_class_name = current_class_stack[current_class_depth].name;
7581 current_class_type = current_class_stack[current_class_depth].type;
7582 current_access_specifier = current_class_stack[current_class_depth].access;
7583 if (current_class_stack[current_class_depth].names_used)
7584 splay_tree_delete (current_class_stack[current_class_depth].names_used);
7585 }
7586
7587 /* Mark the top of the class stack as hidden. */
7588
7589 void
push_class_stack(void)7590 push_class_stack (void)
7591 {
7592 if (current_class_depth)
7593 ++current_class_stack[current_class_depth - 1].hidden;
7594 }
7595
7596 /* Mark the top of the class stack as un-hidden. */
7597
7598 void
pop_class_stack(void)7599 pop_class_stack (void)
7600 {
7601 if (current_class_depth)
7602 --current_class_stack[current_class_depth - 1].hidden;
7603 }
7604
7605 /* If the class type currently being defined is either T or
7606 a nested type of T, returns the type from the current_class_stack,
7607 which might be equivalent to but not equal to T in case of
7608 constrained partial specializations. */
7609
7610 tree
currently_open_class(tree t)7611 currently_open_class (tree t)
7612 {
7613 int i;
7614
7615 if (!CLASS_TYPE_P (t))
7616 return NULL_TREE;
7617
7618 t = TYPE_MAIN_VARIANT (t);
7619
7620 /* We start looking from 1 because entry 0 is from global scope,
7621 and has no type. */
7622 for (i = current_class_depth; i > 0; --i)
7623 {
7624 tree c;
7625 if (i == current_class_depth)
7626 c = current_class_type;
7627 else
7628 {
7629 if (current_class_stack[i].hidden)
7630 break;
7631 c = current_class_stack[i].type;
7632 }
7633 if (!c)
7634 continue;
7635 if (same_type_p (c, t))
7636 return c;
7637 }
7638 return NULL_TREE;
7639 }
7640
7641 /* If either current_class_type or one of its enclosing classes are derived
7642 from T, return the appropriate type. Used to determine how we found
7643 something via unqualified lookup. */
7644
7645 tree
currently_open_derived_class(tree t)7646 currently_open_derived_class (tree t)
7647 {
7648 int i;
7649
7650 /* The bases of a dependent type are unknown. */
7651 if (dependent_type_p (t))
7652 return NULL_TREE;
7653
7654 if (!current_class_type)
7655 return NULL_TREE;
7656
7657 if (DERIVED_FROM_P (t, current_class_type))
7658 return current_class_type;
7659
7660 for (i = current_class_depth - 1; i > 0; --i)
7661 {
7662 if (current_class_stack[i].hidden)
7663 break;
7664 if (DERIVED_FROM_P (t, current_class_stack[i].type))
7665 return current_class_stack[i].type;
7666 }
7667
7668 return NULL_TREE;
7669 }
7670
7671 /* Return the outermost enclosing class type that is still open, or
7672 NULL_TREE. */
7673
7674 tree
outermost_open_class(void)7675 outermost_open_class (void)
7676 {
7677 if (!current_class_type)
7678 return NULL_TREE;
7679 tree r = NULL_TREE;
7680 if (TYPE_BEING_DEFINED (current_class_type))
7681 r = current_class_type;
7682 for (int i = current_class_depth - 1; i > 0; --i)
7683 {
7684 if (current_class_stack[i].hidden)
7685 break;
7686 tree t = current_class_stack[i].type;
7687 if (!TYPE_BEING_DEFINED (t))
7688 break;
7689 r = t;
7690 }
7691 return r;
7692 }
7693
7694 /* Returns the innermost class type which is not a lambda closure type. */
7695
7696 tree
current_nonlambda_class_type(void)7697 current_nonlambda_class_type (void)
7698 {
7699 tree type = current_class_type;
7700 while (type && LAMBDA_TYPE_P (type))
7701 type = decl_type_context (TYPE_NAME (type));
7702 return type;
7703 }
7704
7705 /* When entering a class scope, all enclosing class scopes' names with
7706 static meaning (static variables, static functions, types and
7707 enumerators) have to be visible. This recursive function calls
7708 pushclass for all enclosing class contexts until global or a local
7709 scope is reached. TYPE is the enclosed class. */
7710
7711 void
push_nested_class(tree type)7712 push_nested_class (tree type)
7713 {
7714 /* A namespace might be passed in error cases, like A::B:C. */
7715 if (type == NULL_TREE
7716 || !CLASS_TYPE_P (type))
7717 return;
7718
7719 push_nested_class (DECL_CONTEXT (TYPE_MAIN_DECL (type)));
7720
7721 pushclass (type);
7722 }
7723
7724 /* Undoes a push_nested_class call. */
7725
7726 void
pop_nested_class(void)7727 pop_nested_class (void)
7728 {
7729 tree context = DECL_CONTEXT (TYPE_MAIN_DECL (current_class_type));
7730
7731 popclass ();
7732 if (context && CLASS_TYPE_P (context))
7733 pop_nested_class ();
7734 }
7735
7736 /* Returns the number of extern "LANG" blocks we are nested within. */
7737
7738 int
current_lang_depth(void)7739 current_lang_depth (void)
7740 {
7741 return vec_safe_length (current_lang_base);
7742 }
7743
7744 /* Set global variables CURRENT_LANG_NAME to appropriate value
7745 so that behavior of name-mangling machinery is correct. */
7746
7747 void
push_lang_context(tree name)7748 push_lang_context (tree name)
7749 {
7750 vec_safe_push (current_lang_base, current_lang_name);
7751
7752 if (name == lang_name_cplusplus)
7753 current_lang_name = name;
7754 else if (name == lang_name_c)
7755 current_lang_name = name;
7756 else
7757 error ("language string %<\"%E\"%> not recognized", name);
7758 }
7759
7760 /* Get out of the current language scope. */
7761
7762 void
pop_lang_context(void)7763 pop_lang_context (void)
7764 {
7765 current_lang_name = current_lang_base->pop ();
7766 }
7767
7768 /* Type instantiation routines. */
7769
7770 /* Given an OVERLOAD and a TARGET_TYPE, return the function that
7771 matches the TARGET_TYPE. If there is no satisfactory match, return
7772 error_mark_node, and issue an error & warning messages under
7773 control of FLAGS. Permit pointers to member function if FLAGS
7774 permits. If TEMPLATE_ONLY, the name of the overloaded function was
7775 a template-id, and EXPLICIT_TARGS are the explicitly provided
7776 template arguments.
7777
7778 If OVERLOAD is for one or more member functions, then ACCESS_PATH
7779 is the base path used to reference those member functions. If
7780 the address is resolved to a member function, access checks will be
7781 performed and errors issued if appropriate. */
7782
7783 static tree
resolve_address_of_overloaded_function(tree target_type,tree overload,tsubst_flags_t complain,bool template_only,tree explicit_targs,tree access_path)7784 resolve_address_of_overloaded_function (tree target_type,
7785 tree overload,
7786 tsubst_flags_t complain,
7787 bool template_only,
7788 tree explicit_targs,
7789 tree access_path)
7790 {
7791 /* Here's what the standard says:
7792
7793 [over.over]
7794
7795 If the name is a function template, template argument deduction
7796 is done, and if the argument deduction succeeds, the deduced
7797 arguments are used to generate a single template function, which
7798 is added to the set of overloaded functions considered.
7799
7800 Non-member functions and static member functions match targets of
7801 type "pointer-to-function" or "reference-to-function." Nonstatic
7802 member functions match targets of type "pointer-to-member
7803 function;" the function type of the pointer to member is used to
7804 select the member function from the set of overloaded member
7805 functions. If a nonstatic member function is selected, the
7806 reference to the overloaded function name is required to have the
7807 form of a pointer to member as described in 5.3.1.
7808
7809 If more than one function is selected, any template functions in
7810 the set are eliminated if the set also contains a non-template
7811 function, and any given template function is eliminated if the
7812 set contains a second template function that is more specialized
7813 than the first according to the partial ordering rules 14.5.5.2.
7814 After such eliminations, if any, there shall remain exactly one
7815 selected function. */
7816
7817 int is_ptrmem = 0;
7818 /* We store the matches in a TREE_LIST rooted here. The functions
7819 are the TREE_PURPOSE, not the TREE_VALUE, in this list, for easy
7820 interoperability with most_specialized_instantiation. */
7821 tree matches = NULL_TREE;
7822 tree fn;
7823 tree target_fn_type;
7824
7825 /* By the time we get here, we should be seeing only real
7826 pointer-to-member types, not the internal POINTER_TYPE to
7827 METHOD_TYPE representation. */
7828 gcc_assert (!TYPE_PTR_P (target_type)
7829 || TREE_CODE (TREE_TYPE (target_type)) != METHOD_TYPE);
7830
7831 gcc_assert (is_overloaded_fn (overload));
7832
7833 /* Check that the TARGET_TYPE is reasonable. */
7834 if (TYPE_PTRFN_P (target_type)
7835 || TYPE_REFFN_P (target_type))
7836 /* This is OK. */;
7837 else if (TYPE_PTRMEMFUNC_P (target_type))
7838 /* This is OK, too. */
7839 is_ptrmem = 1;
7840 else if (TREE_CODE (target_type) == FUNCTION_TYPE)
7841 /* This is OK, too. This comes from a conversion to reference
7842 type. */
7843 target_type = build_reference_type (target_type);
7844 else
7845 {
7846 if (complain & tf_error)
7847 error ("cannot resolve overloaded function %qD based on"
7848 " conversion to type %qT",
7849 OVL_NAME (overload), target_type);
7850 return error_mark_node;
7851 }
7852
7853 /* Non-member functions and static member functions match targets of type
7854 "pointer-to-function" or "reference-to-function." Nonstatic member
7855 functions match targets of type "pointer-to-member-function;" the
7856 function type of the pointer to member is used to select the member
7857 function from the set of overloaded member functions.
7858
7859 So figure out the FUNCTION_TYPE that we want to match against. */
7860 target_fn_type = static_fn_type (target_type);
7861
7862 /* If we can find a non-template function that matches, we can just
7863 use it. There's no point in generating template instantiations
7864 if we're just going to throw them out anyhow. But, of course, we
7865 can only do this when we don't *need* a template function. */
7866 if (!template_only)
7867 for (lkp_iterator iter (overload); iter; ++iter)
7868 {
7869 tree fn = *iter;
7870
7871 if (TREE_CODE (fn) == TEMPLATE_DECL)
7872 /* We're not looking for templates just yet. */
7873 continue;
7874
7875 if ((TREE_CODE (TREE_TYPE (fn)) == METHOD_TYPE) != is_ptrmem)
7876 /* We're looking for a non-static member, and this isn't
7877 one, or vice versa. */
7878 continue;
7879
7880 /* In C++17 we need the noexcept-qualifier to compare types. */
7881 if (flag_noexcept_type
7882 && !maybe_instantiate_noexcept (fn, complain))
7883 continue;
7884
7885 /* See if there's a match. */
7886 tree fntype = static_fn_type (fn);
7887 if (same_type_p (target_fn_type, fntype)
7888 || fnptr_conv_p (target_fn_type, fntype))
7889 matches = tree_cons (fn, NULL_TREE, matches);
7890 }
7891
7892 /* Now, if we've already got a match (or matches), there's no need
7893 to proceed to the template functions. But, if we don't have a
7894 match we need to look at them, too. */
7895 if (!matches)
7896 {
7897 tree target_arg_types;
7898 tree target_ret_type;
7899 tree *args;
7900 unsigned int nargs, ia;
7901 tree arg;
7902
7903 target_arg_types = TYPE_ARG_TYPES (target_fn_type);
7904 target_ret_type = TREE_TYPE (target_fn_type);
7905
7906 nargs = list_length (target_arg_types);
7907 args = XALLOCAVEC (tree, nargs);
7908 for (arg = target_arg_types, ia = 0;
7909 arg != NULL_TREE && arg != void_list_node;
7910 arg = TREE_CHAIN (arg), ++ia)
7911 args[ia] = TREE_VALUE (arg);
7912 nargs = ia;
7913
7914 for (lkp_iterator iter (overload); iter; ++iter)
7915 {
7916 tree fn = *iter;
7917 tree instantiation;
7918 tree targs;
7919
7920 if (TREE_CODE (fn) != TEMPLATE_DECL)
7921 /* We're only looking for templates. */
7922 continue;
7923
7924 if ((TREE_CODE (TREE_TYPE (fn)) == METHOD_TYPE)
7925 != is_ptrmem)
7926 /* We're not looking for a non-static member, and this is
7927 one, or vice versa. */
7928 continue;
7929
7930 tree ret = target_ret_type;
7931
7932 /* If the template has a deduced return type, don't expose it to
7933 template argument deduction. */
7934 if (undeduced_auto_decl (fn))
7935 ret = NULL_TREE;
7936
7937 /* Try to do argument deduction. */
7938 targs = make_tree_vec (DECL_NTPARMS (fn));
7939 instantiation = fn_type_unification (fn, explicit_targs, targs, args,
7940 nargs, ret,
7941 DEDUCE_EXACT, LOOKUP_NORMAL,
7942 NULL, false, false);
7943 if (instantiation == error_mark_node)
7944 /* Instantiation failed. */
7945 continue;
7946
7947 /* Constraints must be satisfied. This is done before
7948 return type deduction since that instantiates the
7949 function. */
7950 if (flag_concepts && !constraints_satisfied_p (instantiation))
7951 continue;
7952
7953 /* And now force instantiation to do return type deduction. */
7954 if (undeduced_auto_decl (instantiation))
7955 {
7956 ++function_depth;
7957 instantiate_decl (instantiation, /*defer*/false, /*class*/false);
7958 --function_depth;
7959
7960 require_deduced_type (instantiation);
7961 }
7962
7963 /* In C++17 we need the noexcept-qualifier to compare types. */
7964 if (flag_noexcept_type)
7965 maybe_instantiate_noexcept (instantiation, complain);
7966
7967 /* See if there's a match. */
7968 tree fntype = static_fn_type (instantiation);
7969 if (same_type_p (target_fn_type, fntype)
7970 || fnptr_conv_p (target_fn_type, fntype))
7971 matches = tree_cons (instantiation, fn, matches);
7972 }
7973
7974 /* Now, remove all but the most specialized of the matches. */
7975 if (matches)
7976 {
7977 tree match = most_specialized_instantiation (matches);
7978
7979 if (match != error_mark_node)
7980 matches = tree_cons (TREE_PURPOSE (match),
7981 NULL_TREE,
7982 NULL_TREE);
7983 }
7984 }
7985
7986 /* Now we should have exactly one function in MATCHES. */
7987 if (matches == NULL_TREE)
7988 {
7989 /* There were *no* matches. */
7990 if (complain & tf_error)
7991 {
7992 error ("no matches converting function %qD to type %q#T",
7993 OVL_NAME (overload), target_type);
7994
7995 print_candidates (overload);
7996 }
7997 return error_mark_node;
7998 }
7999 else if (TREE_CHAIN (matches))
8000 {
8001 /* There were too many matches. First check if they're all
8002 the same function. */
8003 tree match = NULL_TREE;
8004
8005 fn = TREE_PURPOSE (matches);
8006
8007 /* For multi-versioned functions, more than one match is just fine and
8008 decls_match will return false as they are different. */
8009 for (match = TREE_CHAIN (matches); match; match = TREE_CHAIN (match))
8010 if (!decls_match (fn, TREE_PURPOSE (match))
8011 && !targetm.target_option.function_versions
8012 (fn, TREE_PURPOSE (match)))
8013 break;
8014
8015 if (match)
8016 {
8017 if (complain & tf_error)
8018 {
8019 error ("converting overloaded function %qD to type %q#T is ambiguous",
8020 OVL_NAME (overload), target_type);
8021
8022 /* Since print_candidates expects the functions in the
8023 TREE_VALUE slot, we flip them here. */
8024 for (match = matches; match; match = TREE_CHAIN (match))
8025 TREE_VALUE (match) = TREE_PURPOSE (match);
8026
8027 print_candidates (matches);
8028 }
8029
8030 return error_mark_node;
8031 }
8032 }
8033
8034 /* Good, exactly one match. Now, convert it to the correct type. */
8035 fn = TREE_PURPOSE (matches);
8036
8037 if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fn)
8038 && !(complain & tf_ptrmem_ok) && !flag_ms_extensions)
8039 {
8040 static int explained;
8041
8042 if (!(complain & tf_error))
8043 return error_mark_node;
8044
8045 auto_diagnostic_group d;
8046 if (permerror (input_location, "assuming pointer to member %qD", fn)
8047 && !explained)
8048 {
8049 inform (input_location, "(a pointer to member can only be "
8050 "formed with %<&%E%>)", fn);
8051 explained = 1;
8052 }
8053 }
8054
8055 /* If a pointer to a function that is multi-versioned is requested, the
8056 pointer to the dispatcher function is returned instead. This works
8057 well because indirectly calling the function will dispatch the right
8058 function version at run-time. */
8059 if (DECL_FUNCTION_VERSIONED (fn))
8060 {
8061 fn = get_function_version_dispatcher (fn);
8062 if (fn == NULL)
8063 return error_mark_node;
8064 /* Mark all the versions corresponding to the dispatcher as used. */
8065 if (!(complain & tf_conv))
8066 mark_versions_used (fn);
8067 }
8068
8069 /* If we're doing overload resolution purely for the purpose of
8070 determining conversion sequences, we should not consider the
8071 function used. If this conversion sequence is selected, the
8072 function will be marked as used at this point. */
8073 if (!(complain & tf_conv))
8074 {
8075 /* Make =delete work with SFINAE. */
8076 if (DECL_DELETED_FN (fn) && !(complain & tf_error))
8077 return error_mark_node;
8078 if (!mark_used (fn, complain) && !(complain & tf_error))
8079 return error_mark_node;
8080 }
8081
8082 /* We could not check access to member functions when this
8083 expression was originally created since we did not know at that
8084 time to which function the expression referred. */
8085 if (DECL_FUNCTION_MEMBER_P (fn))
8086 {
8087 gcc_assert (access_path);
8088 perform_or_defer_access_check (access_path, fn, fn, complain);
8089 }
8090
8091 if (TYPE_PTRFN_P (target_type) || TYPE_PTRMEMFUNC_P (target_type))
8092 return cp_build_addr_expr (fn, complain);
8093 else
8094 {
8095 /* The target must be a REFERENCE_TYPE. Above, cp_build_unary_op
8096 will mark the function as addressed, but here we must do it
8097 explicitly. */
8098 cxx_mark_addressable (fn);
8099
8100 return fn;
8101 }
8102 }
8103
8104 /* This function will instantiate the type of the expression given in
8105 RHS to match the type of LHSTYPE. If errors exist, then return
8106 error_mark_node. COMPLAIN is a bit mask. If TF_ERROR is set, then
8107 we complain on errors. If we are not complaining, never modify rhs,
8108 as overload resolution wants to try many possible instantiations, in
8109 the hope that at least one will work.
8110
8111 For non-recursive calls, LHSTYPE should be a function, pointer to
8112 function, or a pointer to member function. */
8113
8114 tree
instantiate_type(tree lhstype,tree rhs,tsubst_flags_t complain)8115 instantiate_type (tree lhstype, tree rhs, tsubst_flags_t complain)
8116 {
8117 tsubst_flags_t complain_in = complain;
8118 tree access_path = NULL_TREE;
8119
8120 complain &= ~tf_ptrmem_ok;
8121
8122 if (lhstype == unknown_type_node)
8123 {
8124 if (complain & tf_error)
8125 error ("not enough type information");
8126 return error_mark_node;
8127 }
8128
8129 if (TREE_TYPE (rhs) != NULL_TREE && ! (type_unknown_p (rhs)))
8130 {
8131 tree fntype = non_reference (lhstype);
8132 if (same_type_p (fntype, TREE_TYPE (rhs)))
8133 return rhs;
8134 if (fnptr_conv_p (fntype, TREE_TYPE (rhs)))
8135 return rhs;
8136 if (flag_ms_extensions
8137 && TYPE_PTRMEMFUNC_P (fntype)
8138 && !TYPE_PTRMEMFUNC_P (TREE_TYPE (rhs)))
8139 /* Microsoft allows `A::f' to be resolved to a
8140 pointer-to-member. */
8141 ;
8142 else
8143 {
8144 if (complain & tf_error)
8145 error ("cannot convert %qE from type %qT to type %qT",
8146 rhs, TREE_TYPE (rhs), fntype);
8147 return error_mark_node;
8148 }
8149 }
8150
8151 /* If we instantiate a template, and it is a A ?: C expression
8152 with omitted B, look through the SAVE_EXPR. */
8153 if (TREE_CODE (rhs) == SAVE_EXPR)
8154 rhs = TREE_OPERAND (rhs, 0);
8155
8156 if (BASELINK_P (rhs))
8157 {
8158 access_path = BASELINK_ACCESS_BINFO (rhs);
8159 rhs = BASELINK_FUNCTIONS (rhs);
8160 }
8161
8162 /* If we are in a template, and have a NON_DEPENDENT_EXPR, we cannot
8163 deduce any type information. */
8164 if (TREE_CODE (rhs) == NON_DEPENDENT_EXPR)
8165 {
8166 if (complain & tf_error)
8167 error ("not enough type information");
8168 return error_mark_node;
8169 }
8170
8171 /* There are only a few kinds of expressions that may have a type
8172 dependent on overload resolution. */
8173 gcc_assert (TREE_CODE (rhs) == ADDR_EXPR
8174 || TREE_CODE (rhs) == COMPONENT_REF
8175 || is_overloaded_fn (rhs)
8176 || (flag_ms_extensions && TREE_CODE (rhs) == FUNCTION_DECL));
8177
8178 /* This should really only be used when attempting to distinguish
8179 what sort of a pointer to function we have. For now, any
8180 arithmetic operation which is not supported on pointers
8181 is rejected as an error. */
8182
8183 switch (TREE_CODE (rhs))
8184 {
8185 case COMPONENT_REF:
8186 {
8187 tree member = TREE_OPERAND (rhs, 1);
8188
8189 member = instantiate_type (lhstype, member, complain);
8190 if (member != error_mark_node
8191 && TREE_SIDE_EFFECTS (TREE_OPERAND (rhs, 0)))
8192 /* Do not lose object's side effects. */
8193 return build2 (COMPOUND_EXPR, TREE_TYPE (member),
8194 TREE_OPERAND (rhs, 0), member);
8195 return member;
8196 }
8197
8198 case OFFSET_REF:
8199 rhs = TREE_OPERAND (rhs, 1);
8200 if (BASELINK_P (rhs))
8201 return instantiate_type (lhstype, rhs, complain_in);
8202
8203 /* This can happen if we are forming a pointer-to-member for a
8204 member template. */
8205 gcc_assert (TREE_CODE (rhs) == TEMPLATE_ID_EXPR);
8206
8207 /* Fall through. */
8208
8209 case TEMPLATE_ID_EXPR:
8210 {
8211 tree fns = TREE_OPERAND (rhs, 0);
8212 tree args = TREE_OPERAND (rhs, 1);
8213
8214 return
8215 resolve_address_of_overloaded_function (lhstype, fns, complain_in,
8216 /*template_only=*/true,
8217 args, access_path);
8218 }
8219
8220 case OVERLOAD:
8221 case FUNCTION_DECL:
8222 return
8223 resolve_address_of_overloaded_function (lhstype, rhs, complain_in,
8224 /*template_only=*/false,
8225 /*explicit_targs=*/NULL_TREE,
8226 access_path);
8227
8228 case ADDR_EXPR:
8229 {
8230 if (PTRMEM_OK_P (rhs))
8231 complain |= tf_ptrmem_ok;
8232
8233 return instantiate_type (lhstype, TREE_OPERAND (rhs, 0), complain);
8234 }
8235
8236 case ERROR_MARK:
8237 return error_mark_node;
8238
8239 default:
8240 gcc_unreachable ();
8241 }
8242 return error_mark_node;
8243 }
8244
8245 /* Return the name of the virtual function pointer field
8246 (as an IDENTIFIER_NODE) for the given TYPE. Note that
8247 this may have to look back through base types to find the
8248 ultimate field name. (For single inheritance, these could
8249 all be the same name. Who knows for multiple inheritance). */
8250
8251 static tree
get_vfield_name(tree type)8252 get_vfield_name (tree type)
8253 {
8254 tree binfo, base_binfo;
8255
8256 for (binfo = TYPE_BINFO (type);
8257 BINFO_N_BASE_BINFOS (binfo);
8258 binfo = base_binfo)
8259 {
8260 base_binfo = BINFO_BASE_BINFO (binfo, 0);
8261
8262 if (BINFO_VIRTUAL_P (base_binfo)
8263 || !TYPE_CONTAINS_VPTR_P (BINFO_TYPE (base_binfo)))
8264 break;
8265 }
8266
8267 type = BINFO_TYPE (binfo);
8268 tree ctor_name = constructor_name (type);
8269 char *buf = (char *) alloca (sizeof (VFIELD_NAME_FORMAT)
8270 + IDENTIFIER_LENGTH (ctor_name) + 2);
8271 sprintf (buf, VFIELD_NAME_FORMAT, IDENTIFIER_POINTER (ctor_name));
8272 return get_identifier (buf);
8273 }
8274
8275 /* Build a dummy reference to ourselves so Derived::Base (and A::A) works,
8276 according to [class]:
8277 The class-name is also inserted
8278 into the scope of the class itself. For purposes of access checking,
8279 the inserted class name is treated as if it were a public member name. */
8280
8281 void
build_self_reference(void)8282 build_self_reference (void)
8283 {
8284 tree name = DECL_NAME (TYPE_NAME (current_class_type));
8285 tree value = build_lang_decl (TYPE_DECL, name, current_class_type);
8286
8287 DECL_NONLOCAL (value) = 1;
8288 DECL_CONTEXT (value) = current_class_type;
8289 DECL_ARTIFICIAL (value) = 1;
8290 SET_DECL_SELF_REFERENCE_P (value);
8291 set_underlying_type (value);
8292
8293 if (processing_template_decl)
8294 value = push_template_decl (value);
8295
8296 tree saved_cas = current_access_specifier;
8297 current_access_specifier = access_public_node;
8298 finish_member_declaration (value);
8299 current_access_specifier = saved_cas;
8300 }
8301
8302 /* Returns 1 if TYPE contains only padding bytes. */
8303
8304 int
is_empty_class(tree type)8305 is_empty_class (tree type)
8306 {
8307 if (type == error_mark_node)
8308 return 0;
8309
8310 if (! CLASS_TYPE_P (type))
8311 return 0;
8312
8313 return CLASSTYPE_EMPTY_P (type);
8314 }
8315
8316 /* Returns true if TYPE contains no actual data, just various
8317 possible combinations of empty classes. If IGNORE_VPTR is true,
8318 a vptr doesn't prevent the class from being considered empty. Typically
8319 we want to ignore the vptr on assignment, and not on initialization. */
8320
8321 bool
is_really_empty_class(tree type,bool ignore_vptr)8322 is_really_empty_class (tree type, bool ignore_vptr)
8323 {
8324 if (CLASS_TYPE_P (type))
8325 {
8326 tree field;
8327 tree binfo;
8328 tree base_binfo;
8329 int i;
8330
8331 /* CLASSTYPE_EMPTY_P isn't set properly until the class is actually laid
8332 out, but we'd like to be able to check this before then. */
8333 if (COMPLETE_TYPE_P (type) && is_empty_class (type))
8334 return true;
8335
8336 if (!ignore_vptr && TYPE_CONTAINS_VPTR_P (type))
8337 return false;
8338
8339 for (binfo = TYPE_BINFO (type), i = 0;
8340 BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
8341 if (!is_really_empty_class (BINFO_TYPE (base_binfo), ignore_vptr))
8342 return false;
8343 for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
8344 if (TREE_CODE (field) == FIELD_DECL
8345 && !DECL_ARTIFICIAL (field)
8346 /* An unnamed bit-field is not a data member. */
8347 && !DECL_UNNAMED_BIT_FIELD (field)
8348 && !is_really_empty_class (TREE_TYPE (field), ignore_vptr))
8349 return false;
8350 return true;
8351 }
8352 else if (TREE_CODE (type) == ARRAY_TYPE)
8353 return (integer_zerop (array_type_nelts_top (type))
8354 || is_really_empty_class (TREE_TYPE (type), ignore_vptr));
8355 return false;
8356 }
8357
8358 /* Note that NAME was looked up while the current class was being
8359 defined and that the result of that lookup was DECL. */
8360
8361 void
maybe_note_name_used_in_class(tree name,tree decl)8362 maybe_note_name_used_in_class (tree name, tree decl)
8363 {
8364 splay_tree names_used;
8365
8366 /* If we're not defining a class, there's nothing to do. */
8367 if (!(innermost_scope_kind() == sk_class
8368 && TYPE_BEING_DEFINED (current_class_type)
8369 && !LAMBDA_TYPE_P (current_class_type)))
8370 return;
8371
8372 /* If there's already a binding for this NAME, then we don't have
8373 anything to worry about. */
8374 if (lookup_member (current_class_type, name,
8375 /*protect=*/0, /*want_type=*/false, tf_warning_or_error))
8376 return;
8377
8378 if (!current_class_stack[current_class_depth - 1].names_used)
8379 current_class_stack[current_class_depth - 1].names_used
8380 = splay_tree_new (splay_tree_compare_pointers, 0, 0);
8381 names_used = current_class_stack[current_class_depth - 1].names_used;
8382
8383 splay_tree_insert (names_used,
8384 (splay_tree_key) name,
8385 (splay_tree_value) decl);
8386 }
8387
8388 /* Note that NAME was declared (as DECL) in the current class. Check
8389 to see that the declaration is valid. */
8390
8391 void
note_name_declared_in_class(tree name,tree decl)8392 note_name_declared_in_class (tree name, tree decl)
8393 {
8394 splay_tree names_used;
8395 splay_tree_node n;
8396
8397 /* Look to see if we ever used this name. */
8398 names_used
8399 = current_class_stack[current_class_depth - 1].names_used;
8400 if (!names_used)
8401 return;
8402 /* The C language allows members to be declared with a type of the same
8403 name, and the C++ standard says this diagnostic is not required. So
8404 allow it in extern "C" blocks unless predantic is specified.
8405 Allow it in all cases if -ms-extensions is specified. */
8406 if ((!pedantic && current_lang_name == lang_name_c)
8407 || flag_ms_extensions)
8408 return;
8409 n = splay_tree_lookup (names_used, (splay_tree_key) name);
8410 if (n)
8411 {
8412 /* [basic.scope.class]
8413
8414 A name N used in a class S shall refer to the same declaration
8415 in its context and when re-evaluated in the completed scope of
8416 S. */
8417 if (permerror (location_of (decl),
8418 "declaration of %q#D changes meaning of %qD",
8419 decl, OVL_NAME (decl)))
8420 inform (location_of ((tree) n->value),
8421 "%qD declared here as %q#D",
8422 OVL_NAME (decl), (tree) n->value);
8423 }
8424 }
8425
8426 /* Returns the VAR_DECL for the complete vtable associated with BINFO.
8427 Secondary vtables are merged with primary vtables; this function
8428 will return the VAR_DECL for the primary vtable. */
8429
8430 tree
get_vtbl_decl_for_binfo(tree binfo)8431 get_vtbl_decl_for_binfo (tree binfo)
8432 {
8433 tree decl;
8434
8435 decl = BINFO_VTABLE (binfo);
8436 if (decl && TREE_CODE (decl) == POINTER_PLUS_EXPR)
8437 {
8438 gcc_assert (TREE_CODE (TREE_OPERAND (decl, 0)) == ADDR_EXPR);
8439 decl = TREE_OPERAND (TREE_OPERAND (decl, 0), 0);
8440 }
8441 if (decl)
8442 gcc_assert (VAR_P (decl));
8443 return decl;
8444 }
8445
8446
8447 /* Returns the binfo for the primary base of BINFO. If the resulting
8448 BINFO is a virtual base, and it is inherited elsewhere in the
8449 hierarchy, then the returned binfo might not be the primary base of
8450 BINFO in the complete object. Check BINFO_PRIMARY_P or
8451 BINFO_LOST_PRIMARY_P to be sure. */
8452
8453 static tree
get_primary_binfo(tree binfo)8454 get_primary_binfo (tree binfo)
8455 {
8456 tree primary_base;
8457
8458 primary_base = CLASSTYPE_PRIMARY_BINFO (BINFO_TYPE (binfo));
8459 if (!primary_base)
8460 return NULL_TREE;
8461
8462 return copied_binfo (primary_base, binfo);
8463 }
8464
8465 /* As above, but iterate until we reach the binfo that actually provides the
8466 vptr for BINFO. */
8467
8468 static tree
most_primary_binfo(tree binfo)8469 most_primary_binfo (tree binfo)
8470 {
8471 tree b = binfo;
8472 while (CLASSTYPE_HAS_PRIMARY_BASE_P (BINFO_TYPE (b))
8473 && !BINFO_LOST_PRIMARY_P (b))
8474 {
8475 tree primary_base = get_primary_binfo (b);
8476 gcc_assert (BINFO_PRIMARY_P (primary_base)
8477 && BINFO_INHERITANCE_CHAIN (primary_base) == b);
8478 b = primary_base;
8479 }
8480 return b;
8481 }
8482
8483 /* Returns true if BINFO gets its vptr from a virtual base of the most derived
8484 type. Note that the virtual inheritance might be above or below BINFO in
8485 the hierarchy. */
8486
8487 bool
vptr_via_virtual_p(tree binfo)8488 vptr_via_virtual_p (tree binfo)
8489 {
8490 if (TYPE_P (binfo))
8491 binfo = TYPE_BINFO (binfo);
8492 tree primary = most_primary_binfo (binfo);
8493 /* Don't limit binfo_via_virtual, we want to return true when BINFO itself is
8494 a morally virtual base. */
8495 tree virt = binfo_via_virtual (primary, NULL_TREE);
8496 return virt != NULL_TREE;
8497 }
8498
8499 /* If INDENTED_P is zero, indent to INDENT. Return nonzero. */
8500
8501 static int
maybe_indent_hierarchy(FILE * stream,int indent,int indented_p)8502 maybe_indent_hierarchy (FILE * stream, int indent, int indented_p)
8503 {
8504 if (!indented_p)
8505 fprintf (stream, "%*s", indent, "");
8506 return 1;
8507 }
8508
8509 /* Dump the offsets of all the bases rooted at BINFO to STREAM.
8510 INDENT should be zero when called from the top level; it is
8511 incremented recursively. IGO indicates the next expected BINFO in
8512 inheritance graph ordering. */
8513
8514 static tree
dump_class_hierarchy_r(FILE * stream,dump_flags_t flags,tree binfo,tree igo,int indent)8515 dump_class_hierarchy_r (FILE *stream,
8516 dump_flags_t flags,
8517 tree binfo,
8518 tree igo,
8519 int indent)
8520 {
8521 int indented = 0;
8522 tree base_binfo;
8523 int i;
8524
8525 indented = maybe_indent_hierarchy (stream, indent, 0);
8526 fprintf (stream, "%s (0x" HOST_WIDE_INT_PRINT_HEX ") ",
8527 type_as_string (BINFO_TYPE (binfo), TFF_PLAIN_IDENTIFIER),
8528 (HOST_WIDE_INT) (uintptr_t) binfo);
8529 if (binfo != igo)
8530 {
8531 fprintf (stream, "alternative-path\n");
8532 return igo;
8533 }
8534 igo = TREE_CHAIN (binfo);
8535
8536 fprintf (stream, HOST_WIDE_INT_PRINT_DEC,
8537 tree_to_shwi (BINFO_OFFSET (binfo)));
8538 if (is_empty_class (BINFO_TYPE (binfo)))
8539 fprintf (stream, " empty");
8540 else if (CLASSTYPE_NEARLY_EMPTY_P (BINFO_TYPE (binfo)))
8541 fprintf (stream, " nearly-empty");
8542 if (BINFO_VIRTUAL_P (binfo))
8543 fprintf (stream, " virtual");
8544 fprintf (stream, "\n");
8545
8546 indented = 0;
8547 if (BINFO_PRIMARY_P (binfo))
8548 {
8549 indented = maybe_indent_hierarchy (stream, indent + 3, indented);
8550 fprintf (stream, " primary-for %s (0x" HOST_WIDE_INT_PRINT_HEX ")",
8551 type_as_string (BINFO_TYPE (BINFO_INHERITANCE_CHAIN (binfo)),
8552 TFF_PLAIN_IDENTIFIER),
8553 (HOST_WIDE_INT) (uintptr_t) BINFO_INHERITANCE_CHAIN (binfo));
8554 }
8555 if (BINFO_LOST_PRIMARY_P (binfo))
8556 {
8557 indented = maybe_indent_hierarchy (stream, indent + 3, indented);
8558 fprintf (stream, " lost-primary");
8559 }
8560 if (indented)
8561 fprintf (stream, "\n");
8562
8563 if (!(flags & TDF_SLIM))
8564 {
8565 int indented = 0;
8566
8567 if (BINFO_SUBVTT_INDEX (binfo))
8568 {
8569 indented = maybe_indent_hierarchy (stream, indent + 3, indented);
8570 fprintf (stream, " subvttidx=%s",
8571 expr_as_string (BINFO_SUBVTT_INDEX (binfo),
8572 TFF_PLAIN_IDENTIFIER));
8573 }
8574 if (BINFO_VPTR_INDEX (binfo))
8575 {
8576 indented = maybe_indent_hierarchy (stream, indent + 3, indented);
8577 fprintf (stream, " vptridx=%s",
8578 expr_as_string (BINFO_VPTR_INDEX (binfo),
8579 TFF_PLAIN_IDENTIFIER));
8580 }
8581 if (BINFO_VPTR_FIELD (binfo))
8582 {
8583 indented = maybe_indent_hierarchy (stream, indent + 3, indented);
8584 fprintf (stream, " vbaseoffset=%s",
8585 expr_as_string (BINFO_VPTR_FIELD (binfo),
8586 TFF_PLAIN_IDENTIFIER));
8587 }
8588 if (BINFO_VTABLE (binfo))
8589 {
8590 indented = maybe_indent_hierarchy (stream, indent + 3, indented);
8591 fprintf (stream, " vptr=%s",
8592 expr_as_string (BINFO_VTABLE (binfo),
8593 TFF_PLAIN_IDENTIFIER));
8594 }
8595
8596 if (indented)
8597 fprintf (stream, "\n");
8598 }
8599
8600 for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
8601 igo = dump_class_hierarchy_r (stream, flags, base_binfo, igo, indent + 2);
8602
8603 return igo;
8604 }
8605
8606 /* Dump the BINFO hierarchy for T. */
8607
8608 static void
dump_class_hierarchy_1(FILE * stream,dump_flags_t flags,tree t)8609 dump_class_hierarchy_1 (FILE *stream, dump_flags_t flags, tree t)
8610 {
8611 fprintf (stream, "Class %s\n", type_as_string (t, TFF_PLAIN_IDENTIFIER));
8612 fprintf (stream, " size=%lu align=%lu\n",
8613 (unsigned long)(tree_to_shwi (TYPE_SIZE (t)) / BITS_PER_UNIT),
8614 (unsigned long)(TYPE_ALIGN (t) / BITS_PER_UNIT));
8615 fprintf (stream, " base size=%lu base align=%lu\n",
8616 (unsigned long)(tree_to_shwi (TYPE_SIZE (CLASSTYPE_AS_BASE (t)))
8617 / BITS_PER_UNIT),
8618 (unsigned long)(TYPE_ALIGN (CLASSTYPE_AS_BASE (t))
8619 / BITS_PER_UNIT));
8620 dump_class_hierarchy_r (stream, flags, TYPE_BINFO (t), TYPE_BINFO (t), 0);
8621 fprintf (stream, "\n");
8622 }
8623
8624 /* Debug interface to hierarchy dumping. */
8625
8626 void
debug_class(tree t)8627 debug_class (tree t)
8628 {
8629 dump_class_hierarchy_1 (stderr, TDF_SLIM, t);
8630 }
8631
8632 static void
dump_class_hierarchy(tree t)8633 dump_class_hierarchy (tree t)
8634 {
8635 dump_flags_t flags;
8636 if (FILE *stream = dump_begin (class_dump_id, &flags))
8637 {
8638 dump_class_hierarchy_1 (stream, flags, t);
8639 dump_end (class_dump_id, stream);
8640 }
8641 }
8642
8643 static void
dump_array(FILE * stream,tree decl)8644 dump_array (FILE * stream, tree decl)
8645 {
8646 tree value;
8647 unsigned HOST_WIDE_INT ix;
8648 HOST_WIDE_INT elt;
8649 tree size = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (decl)));
8650
8651 elt = (tree_to_shwi (TYPE_SIZE (TREE_TYPE (TREE_TYPE (decl))))
8652 / BITS_PER_UNIT);
8653 fprintf (stream, "%s:", decl_as_string (decl, TFF_PLAIN_IDENTIFIER));
8654 fprintf (stream, " %s entries",
8655 expr_as_string (size_binop (PLUS_EXPR, size, size_one_node),
8656 TFF_PLAIN_IDENTIFIER));
8657 fprintf (stream, "\n");
8658
8659 FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (DECL_INITIAL (decl)),
8660 ix, value)
8661 fprintf (stream, "%-4ld %s\n", (long)(ix * elt),
8662 expr_as_string (value, TFF_PLAIN_IDENTIFIER));
8663 }
8664
8665 static void
dump_vtable(tree t,tree binfo,tree vtable)8666 dump_vtable (tree t, tree binfo, tree vtable)
8667 {
8668 dump_flags_t flags;
8669 FILE *stream = dump_begin (class_dump_id, &flags);
8670
8671 if (!stream)
8672 return;
8673
8674 if (!(flags & TDF_SLIM))
8675 {
8676 int ctor_vtbl_p = TYPE_BINFO (t) != binfo;
8677
8678 fprintf (stream, "%s for %s",
8679 ctor_vtbl_p ? "Construction vtable" : "Vtable",
8680 type_as_string (BINFO_TYPE (binfo), TFF_PLAIN_IDENTIFIER));
8681 if (ctor_vtbl_p)
8682 {
8683 if (!BINFO_VIRTUAL_P (binfo))
8684 fprintf (stream, " (0x" HOST_WIDE_INT_PRINT_HEX " instance)",
8685 (HOST_WIDE_INT) (uintptr_t) binfo);
8686 fprintf (stream, " in %s", type_as_string (t, TFF_PLAIN_IDENTIFIER));
8687 }
8688 fprintf (stream, "\n");
8689 dump_array (stream, vtable);
8690 fprintf (stream, "\n");
8691 }
8692
8693 dump_end (class_dump_id, stream);
8694 }
8695
8696 static void
dump_vtt(tree t,tree vtt)8697 dump_vtt (tree t, tree vtt)
8698 {
8699 dump_flags_t flags;
8700 FILE *stream = dump_begin (class_dump_id, &flags);
8701
8702 if (!stream)
8703 return;
8704
8705 if (!(flags & TDF_SLIM))
8706 {
8707 fprintf (stream, "VTT for %s\n",
8708 type_as_string (t, TFF_PLAIN_IDENTIFIER));
8709 dump_array (stream, vtt);
8710 fprintf (stream, "\n");
8711 }
8712
8713 dump_end (class_dump_id, stream);
8714 }
8715
8716 /* Dump a function or thunk and its thunkees. */
8717
8718 static void
dump_thunk(FILE * stream,int indent,tree thunk)8719 dump_thunk (FILE *stream, int indent, tree thunk)
8720 {
8721 static const char spaces[] = " ";
8722 tree name = DECL_NAME (thunk);
8723 tree thunks;
8724
8725 fprintf (stream, "%.*s%p %s %s", indent, spaces,
8726 (void *)thunk,
8727 !DECL_THUNK_P (thunk) ? "function"
8728 : DECL_THIS_THUNK_P (thunk) ? "this-thunk" : "covariant-thunk",
8729 name ? IDENTIFIER_POINTER (name) : "<unset>");
8730 if (DECL_THUNK_P (thunk))
8731 {
8732 HOST_WIDE_INT fixed_adjust = THUNK_FIXED_OFFSET (thunk);
8733 tree virtual_adjust = THUNK_VIRTUAL_OFFSET (thunk);
8734
8735 fprintf (stream, " fixed=" HOST_WIDE_INT_PRINT_DEC, fixed_adjust);
8736 if (!virtual_adjust)
8737 /*NOP*/;
8738 else if (DECL_THIS_THUNK_P (thunk))
8739 fprintf (stream, " vcall=" HOST_WIDE_INT_PRINT_DEC,
8740 tree_to_shwi (virtual_adjust));
8741 else
8742 fprintf (stream, " vbase=" HOST_WIDE_INT_PRINT_DEC "(%s)",
8743 tree_to_shwi (BINFO_VPTR_FIELD (virtual_adjust)),
8744 type_as_string (BINFO_TYPE (virtual_adjust), TFF_SCOPE));
8745 if (THUNK_ALIAS (thunk))
8746 fprintf (stream, " alias to %p", (void *)THUNK_ALIAS (thunk));
8747 }
8748 fprintf (stream, "\n");
8749 for (thunks = DECL_THUNKS (thunk); thunks; thunks = TREE_CHAIN (thunks))
8750 dump_thunk (stream, indent + 2, thunks);
8751 }
8752
8753 /* Dump the thunks for FN. */
8754
8755 void
debug_thunks(tree fn)8756 debug_thunks (tree fn)
8757 {
8758 dump_thunk (stderr, 0, fn);
8759 }
8760
8761 /* Virtual function table initialization. */
8762
8763 /* Create all the necessary vtables for T and its base classes. */
8764
8765 static void
finish_vtbls(tree t)8766 finish_vtbls (tree t)
8767 {
8768 tree vbase;
8769 vec<constructor_elt, va_gc> *v = NULL;
8770 tree vtable = BINFO_VTABLE (TYPE_BINFO (t));
8771
8772 /* We lay out the primary and secondary vtables in one contiguous
8773 vtable. The primary vtable is first, followed by the non-virtual
8774 secondary vtables in inheritance graph order. */
8775 accumulate_vtbl_inits (TYPE_BINFO (t), TYPE_BINFO (t), TYPE_BINFO (t),
8776 vtable, t, &v);
8777
8778 /* Then come the virtual bases, also in inheritance graph order. */
8779 for (vbase = TYPE_BINFO (t); vbase; vbase = TREE_CHAIN (vbase))
8780 {
8781 if (!BINFO_VIRTUAL_P (vbase))
8782 continue;
8783 accumulate_vtbl_inits (vbase, vbase, TYPE_BINFO (t), vtable, t, &v);
8784 }
8785
8786 if (BINFO_VTABLE (TYPE_BINFO (t)))
8787 initialize_vtable (TYPE_BINFO (t), v);
8788 }
8789
8790 /* Initialize the vtable for BINFO with the INITS. */
8791
8792 static void
initialize_vtable(tree binfo,vec<constructor_elt,va_gc> * inits)8793 initialize_vtable (tree binfo, vec<constructor_elt, va_gc> *inits)
8794 {
8795 tree decl;
8796
8797 layout_vtable_decl (binfo, vec_safe_length (inits));
8798 decl = get_vtbl_decl_for_binfo (binfo);
8799 initialize_artificial_var (decl, inits);
8800 dump_vtable (BINFO_TYPE (binfo), binfo, decl);
8801 }
8802
8803 /* Build the VTT (virtual table table) for T.
8804 A class requires a VTT if it has virtual bases.
8805
8806 This holds
8807 1 - primary virtual pointer for complete object T
8808 2 - secondary VTTs for each direct non-virtual base of T which requires a
8809 VTT
8810 3 - secondary virtual pointers for each direct or indirect base of T which
8811 has virtual bases or is reachable via a virtual path from T.
8812 4 - secondary VTTs for each direct or indirect virtual base of T.
8813
8814 Secondary VTTs look like complete object VTTs without part 4. */
8815
8816 static void
build_vtt(tree t)8817 build_vtt (tree t)
8818 {
8819 tree type;
8820 tree vtt;
8821 tree index;
8822 vec<constructor_elt, va_gc> *inits;
8823
8824 /* Build up the initializers for the VTT. */
8825 inits = NULL;
8826 index = size_zero_node;
8827 build_vtt_inits (TYPE_BINFO (t), t, &inits, &index);
8828
8829 /* If we didn't need a VTT, we're done. */
8830 if (!inits)
8831 return;
8832
8833 /* Figure out the type of the VTT. */
8834 type = build_array_of_n_type (const_ptr_type_node,
8835 inits->length ());
8836
8837 /* Now, build the VTT object itself. */
8838 vtt = build_vtable (t, mangle_vtt_for_type (t), type);
8839 initialize_artificial_var (vtt, inits);
8840 /* Add the VTT to the vtables list. */
8841 DECL_CHAIN (vtt) = DECL_CHAIN (CLASSTYPE_VTABLES (t));
8842 DECL_CHAIN (CLASSTYPE_VTABLES (t)) = vtt;
8843
8844 dump_vtt (t, vtt);
8845 }
8846
8847 /* When building a secondary VTT, BINFO_VTABLE is set to a TREE_LIST with
8848 PURPOSE the RTTI_BINFO, VALUE the real vtable pointer for this binfo,
8849 and CHAIN the vtable pointer for this binfo after construction is
8850 complete. VALUE can also be another BINFO, in which case we recurse. */
8851
8852 static tree
binfo_ctor_vtable(tree binfo)8853 binfo_ctor_vtable (tree binfo)
8854 {
8855 tree vt;
8856
8857 while (1)
8858 {
8859 vt = BINFO_VTABLE (binfo);
8860 if (TREE_CODE (vt) == TREE_LIST)
8861 vt = TREE_VALUE (vt);
8862 if (TREE_CODE (vt) == TREE_BINFO)
8863 binfo = vt;
8864 else
8865 break;
8866 }
8867
8868 return vt;
8869 }
8870
8871 /* Data for secondary VTT initialization. */
8872 struct secondary_vptr_vtt_init_data
8873 {
8874 /* Is this the primary VTT? */
8875 bool top_level_p;
8876
8877 /* Current index into the VTT. */
8878 tree index;
8879
8880 /* Vector of initializers built up. */
8881 vec<constructor_elt, va_gc> *inits;
8882
8883 /* The type being constructed by this secondary VTT. */
8884 tree type_being_constructed;
8885 };
8886
8887 /* Recursively build the VTT-initializer for BINFO (which is in the
8888 hierarchy dominated by T). INITS points to the end of the initializer
8889 list to date. INDEX is the VTT index where the next element will be
8890 replaced. Iff BINFO is the binfo for T, this is the top level VTT (i.e.
8891 not a subvtt for some base of T). When that is so, we emit the sub-VTTs
8892 for virtual bases of T. When it is not so, we build the constructor
8893 vtables for the BINFO-in-T variant. */
8894
8895 static void
build_vtt_inits(tree binfo,tree t,vec<constructor_elt,va_gc> ** inits,tree * index)8896 build_vtt_inits (tree binfo, tree t, vec<constructor_elt, va_gc> **inits,
8897 tree *index)
8898 {
8899 int i;
8900 tree b;
8901 tree init;
8902 secondary_vptr_vtt_init_data data;
8903 int top_level_p = SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), t);
8904
8905 /* We only need VTTs for subobjects with virtual bases. */
8906 if (!CLASSTYPE_VBASECLASSES (BINFO_TYPE (binfo)))
8907 return;
8908
8909 /* We need to use a construction vtable if this is not the primary
8910 VTT. */
8911 if (!top_level_p)
8912 {
8913 build_ctor_vtbl_group (binfo, t);
8914
8915 /* Record the offset in the VTT where this sub-VTT can be found. */
8916 BINFO_SUBVTT_INDEX (binfo) = *index;
8917 }
8918
8919 /* Add the address of the primary vtable for the complete object. */
8920 init = binfo_ctor_vtable (binfo);
8921 CONSTRUCTOR_APPEND_ELT (*inits, NULL_TREE, init);
8922 if (top_level_p)
8923 {
8924 gcc_assert (!BINFO_VPTR_INDEX (binfo));
8925 BINFO_VPTR_INDEX (binfo) = *index;
8926 }
8927 *index = size_binop (PLUS_EXPR, *index, TYPE_SIZE_UNIT (ptr_type_node));
8928
8929 /* Recursively add the secondary VTTs for non-virtual bases. */
8930 for (i = 0; BINFO_BASE_ITERATE (binfo, i, b); ++i)
8931 if (!BINFO_VIRTUAL_P (b))
8932 build_vtt_inits (b, t, inits, index);
8933
8934 /* Add secondary virtual pointers for all subobjects of BINFO with
8935 either virtual bases or reachable along a virtual path, except
8936 subobjects that are non-virtual primary bases. */
8937 data.top_level_p = top_level_p;
8938 data.index = *index;
8939 data.inits = *inits;
8940 data.type_being_constructed = BINFO_TYPE (binfo);
8941
8942 dfs_walk_once (binfo, dfs_build_secondary_vptr_vtt_inits, NULL, &data);
8943
8944 *index = data.index;
8945
8946 /* data.inits might have grown as we added secondary virtual pointers.
8947 Make sure our caller knows about the new vector. */
8948 *inits = data.inits;
8949
8950 if (top_level_p)
8951 /* Add the secondary VTTs for virtual bases in inheritance graph
8952 order. */
8953 for (b = TYPE_BINFO (BINFO_TYPE (binfo)); b; b = TREE_CHAIN (b))
8954 {
8955 if (!BINFO_VIRTUAL_P (b))
8956 continue;
8957
8958 build_vtt_inits (b, t, inits, index);
8959 }
8960 else
8961 /* Remove the ctor vtables we created. */
8962 dfs_walk_all (binfo, dfs_fixup_binfo_vtbls, NULL, binfo);
8963 }
8964
8965 /* Called from build_vtt_inits via dfs_walk. BINFO is the binfo for the base
8966 in most derived. DATA is a SECONDARY_VPTR_VTT_INIT_DATA structure. */
8967
8968 static tree
dfs_build_secondary_vptr_vtt_inits(tree binfo,void * data_)8969 dfs_build_secondary_vptr_vtt_inits (tree binfo, void *data_)
8970 {
8971 secondary_vptr_vtt_init_data *data = (secondary_vptr_vtt_init_data *)data_;
8972
8973 /* We don't care about bases that don't have vtables. */
8974 if (!TYPE_VFIELD (BINFO_TYPE (binfo)))
8975 return dfs_skip_bases;
8976
8977 /* We're only interested in proper subobjects of the type being
8978 constructed. */
8979 if (SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), data->type_being_constructed))
8980 return NULL_TREE;
8981
8982 /* We're only interested in bases with virtual bases or reachable
8983 via a virtual path from the type being constructed. */
8984 if (!(CLASSTYPE_VBASECLASSES (BINFO_TYPE (binfo))
8985 || binfo_via_virtual (binfo, data->type_being_constructed)))
8986 return dfs_skip_bases;
8987
8988 /* We're not interested in non-virtual primary bases. */
8989 if (!BINFO_VIRTUAL_P (binfo) && BINFO_PRIMARY_P (binfo))
8990 return NULL_TREE;
8991
8992 /* Record the index where this secondary vptr can be found. */
8993 if (data->top_level_p)
8994 {
8995 gcc_assert (!BINFO_VPTR_INDEX (binfo));
8996 BINFO_VPTR_INDEX (binfo) = data->index;
8997
8998 if (BINFO_VIRTUAL_P (binfo))
8999 {
9000 /* It's a primary virtual base, and this is not a
9001 construction vtable. Find the base this is primary of in
9002 the inheritance graph, and use that base's vtable
9003 now. */
9004 while (BINFO_PRIMARY_P (binfo))
9005 binfo = BINFO_INHERITANCE_CHAIN (binfo);
9006 }
9007 }
9008
9009 /* Add the initializer for the secondary vptr itself. */
9010 CONSTRUCTOR_APPEND_ELT (data->inits, NULL_TREE, binfo_ctor_vtable (binfo));
9011
9012 /* Advance the vtt index. */
9013 data->index = size_binop (PLUS_EXPR, data->index,
9014 TYPE_SIZE_UNIT (ptr_type_node));
9015
9016 return NULL_TREE;
9017 }
9018
9019 /* Called from build_vtt_inits via dfs_walk. After building
9020 constructor vtables and generating the sub-vtt from them, we need
9021 to restore the BINFO_VTABLES that were scribbled on. DATA is the
9022 binfo of the base whose sub vtt was generated. */
9023
9024 static tree
dfs_fixup_binfo_vtbls(tree binfo,void * data)9025 dfs_fixup_binfo_vtbls (tree binfo, void* data)
9026 {
9027 tree vtable = BINFO_VTABLE (binfo);
9028
9029 if (!TYPE_CONTAINS_VPTR_P (BINFO_TYPE (binfo)))
9030 /* If this class has no vtable, none of its bases do. */
9031 return dfs_skip_bases;
9032
9033 if (!vtable)
9034 /* This might be a primary base, so have no vtable in this
9035 hierarchy. */
9036 return NULL_TREE;
9037
9038 /* If we scribbled the construction vtable vptr into BINFO, clear it
9039 out now. */
9040 if (TREE_CODE (vtable) == TREE_LIST
9041 && (TREE_PURPOSE (vtable) == (tree) data))
9042 BINFO_VTABLE (binfo) = TREE_CHAIN (vtable);
9043
9044 return NULL_TREE;
9045 }
9046
9047 /* Build the construction vtable group for BINFO which is in the
9048 hierarchy dominated by T. */
9049
9050 static void
build_ctor_vtbl_group(tree binfo,tree t)9051 build_ctor_vtbl_group (tree binfo, tree t)
9052 {
9053 tree type;
9054 tree vtbl;
9055 tree id;
9056 tree vbase;
9057 vec<constructor_elt, va_gc> *v;
9058
9059 /* See if we've already created this construction vtable group. */
9060 id = mangle_ctor_vtbl_for_type (t, binfo);
9061 if (get_global_binding (id))
9062 return;
9063
9064 gcc_assert (!SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), t));
9065 /* Build a version of VTBL (with the wrong type) for use in
9066 constructing the addresses of secondary vtables in the
9067 construction vtable group. */
9068 vtbl = build_vtable (t, id, ptr_type_node);
9069 DECL_CONSTRUCTION_VTABLE_P (vtbl) = 1;
9070 /* Don't export construction vtables from shared libraries. Even on
9071 targets that don't support hidden visibility, this tells
9072 can_refer_decl_in_current_unit_p not to assume that it's safe to
9073 access from a different compilation unit (bz 54314). */
9074 DECL_VISIBILITY (vtbl) = VISIBILITY_HIDDEN;
9075 DECL_VISIBILITY_SPECIFIED (vtbl) = true;
9076
9077 v = NULL;
9078 accumulate_vtbl_inits (binfo, TYPE_BINFO (TREE_TYPE (binfo)),
9079 binfo, vtbl, t, &v);
9080
9081 /* Add the vtables for each of our virtual bases using the vbase in T
9082 binfo. */
9083 for (vbase = TYPE_BINFO (BINFO_TYPE (binfo));
9084 vbase;
9085 vbase = TREE_CHAIN (vbase))
9086 {
9087 tree b;
9088
9089 if (!BINFO_VIRTUAL_P (vbase))
9090 continue;
9091 b = copied_binfo (vbase, binfo);
9092
9093 accumulate_vtbl_inits (b, vbase, binfo, vtbl, t, &v);
9094 }
9095
9096 /* Figure out the type of the construction vtable. */
9097 type = build_array_of_n_type (vtable_entry_type, v->length ());
9098 layout_type (type);
9099 TREE_TYPE (vtbl) = type;
9100 DECL_SIZE (vtbl) = DECL_SIZE_UNIT (vtbl) = NULL_TREE;
9101 layout_decl (vtbl, 0);
9102
9103 /* Initialize the construction vtable. */
9104 CLASSTYPE_VTABLES (t) = chainon (CLASSTYPE_VTABLES (t), vtbl);
9105 initialize_artificial_var (vtbl, v);
9106 dump_vtable (t, binfo, vtbl);
9107 }
9108
9109 /* Add the vtbl initializers for BINFO (and its bases other than
9110 non-virtual primaries) to the list of INITS. BINFO is in the
9111 hierarchy dominated by T. RTTI_BINFO is the binfo within T of
9112 the constructor the vtbl inits should be accumulated for. (If this
9113 is the complete object vtbl then RTTI_BINFO will be TYPE_BINFO (T).)
9114 ORIG_BINFO is the binfo for this object within BINFO_TYPE (RTTI_BINFO).
9115 BINFO is the active base equivalent of ORIG_BINFO in the inheritance
9116 graph of T. Both BINFO and ORIG_BINFO will have the same BINFO_TYPE,
9117 but are not necessarily the same in terms of layout. */
9118
9119 static void
accumulate_vtbl_inits(tree binfo,tree orig_binfo,tree rtti_binfo,tree vtbl,tree t,vec<constructor_elt,va_gc> ** inits)9120 accumulate_vtbl_inits (tree binfo,
9121 tree orig_binfo,
9122 tree rtti_binfo,
9123 tree vtbl,
9124 tree t,
9125 vec<constructor_elt, va_gc> **inits)
9126 {
9127 int i;
9128 tree base_binfo;
9129 int ctor_vtbl_p = !SAME_BINFO_TYPE_P (BINFO_TYPE (rtti_binfo), t);
9130
9131 gcc_assert (SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), BINFO_TYPE (orig_binfo)));
9132
9133 /* If it doesn't have a vptr, we don't do anything. */
9134 if (!TYPE_CONTAINS_VPTR_P (BINFO_TYPE (binfo)))
9135 return;
9136
9137 /* If we're building a construction vtable, we're not interested in
9138 subobjects that don't require construction vtables. */
9139 if (ctor_vtbl_p
9140 && !CLASSTYPE_VBASECLASSES (BINFO_TYPE (binfo))
9141 && !binfo_via_virtual (orig_binfo, BINFO_TYPE (rtti_binfo)))
9142 return;
9143
9144 /* Build the initializers for the BINFO-in-T vtable. */
9145 dfs_accumulate_vtbl_inits (binfo, orig_binfo, rtti_binfo, vtbl, t, inits);
9146
9147 /* Walk the BINFO and its bases. We walk in preorder so that as we
9148 initialize each vtable we can figure out at what offset the
9149 secondary vtable lies from the primary vtable. We can't use
9150 dfs_walk here because we need to iterate through bases of BINFO
9151 and RTTI_BINFO simultaneously. */
9152 for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
9153 {
9154 /* Skip virtual bases. */
9155 if (BINFO_VIRTUAL_P (base_binfo))
9156 continue;
9157 accumulate_vtbl_inits (base_binfo,
9158 BINFO_BASE_BINFO (orig_binfo, i),
9159 rtti_binfo, vtbl, t,
9160 inits);
9161 }
9162 }
9163
9164 /* Called from accumulate_vtbl_inits. Adds the initializers for the
9165 BINFO vtable to L. */
9166
9167 static void
dfs_accumulate_vtbl_inits(tree binfo,tree orig_binfo,tree rtti_binfo,tree orig_vtbl,tree t,vec<constructor_elt,va_gc> ** l)9168 dfs_accumulate_vtbl_inits (tree binfo,
9169 tree orig_binfo,
9170 tree rtti_binfo,
9171 tree orig_vtbl,
9172 tree t,
9173 vec<constructor_elt, va_gc> **l)
9174 {
9175 tree vtbl = NULL_TREE;
9176 int ctor_vtbl_p = !SAME_BINFO_TYPE_P (BINFO_TYPE (rtti_binfo), t);
9177 int n_inits;
9178
9179 if (ctor_vtbl_p
9180 && BINFO_VIRTUAL_P (orig_binfo) && BINFO_PRIMARY_P (orig_binfo))
9181 {
9182 /* In the hierarchy of BINFO_TYPE (RTTI_BINFO), this is a
9183 primary virtual base. If it is not the same primary in
9184 the hierarchy of T, we'll need to generate a ctor vtable
9185 for it, to place at its location in T. If it is the same
9186 primary, we still need a VTT entry for the vtable, but it
9187 should point to the ctor vtable for the base it is a
9188 primary for within the sub-hierarchy of RTTI_BINFO.
9189
9190 There are three possible cases:
9191
9192 1) We are in the same place.
9193 2) We are a primary base within a lost primary virtual base of
9194 RTTI_BINFO.
9195 3) We are primary to something not a base of RTTI_BINFO. */
9196
9197 tree b;
9198 tree last = NULL_TREE;
9199
9200 /* First, look through the bases we are primary to for RTTI_BINFO
9201 or a virtual base. */
9202 b = binfo;
9203 while (BINFO_PRIMARY_P (b))
9204 {
9205 b = BINFO_INHERITANCE_CHAIN (b);
9206 last = b;
9207 if (BINFO_VIRTUAL_P (b) || b == rtti_binfo)
9208 goto found;
9209 }
9210 /* If we run out of primary links, keep looking down our
9211 inheritance chain; we might be an indirect primary. */
9212 for (b = last; b; b = BINFO_INHERITANCE_CHAIN (b))
9213 if (BINFO_VIRTUAL_P (b) || b == rtti_binfo)
9214 break;
9215 found:
9216
9217 /* If we found RTTI_BINFO, this is case 1. If we found a virtual
9218 base B and it is a base of RTTI_BINFO, this is case 2. In
9219 either case, we share our vtable with LAST, i.e. the
9220 derived-most base within B of which we are a primary. */
9221 if (b == rtti_binfo
9222 || (b && binfo_for_vbase (BINFO_TYPE (b), BINFO_TYPE (rtti_binfo))))
9223 /* Just set our BINFO_VTABLE to point to LAST, as we may not have
9224 set LAST's BINFO_VTABLE yet. We'll extract the actual vptr in
9225 binfo_ctor_vtable after everything's been set up. */
9226 vtbl = last;
9227
9228 /* Otherwise, this is case 3 and we get our own. */
9229 }
9230 else if (!BINFO_NEW_VTABLE_MARKED (orig_binfo))
9231 return;
9232
9233 n_inits = vec_safe_length (*l);
9234
9235 if (!vtbl)
9236 {
9237 tree index;
9238 int non_fn_entries;
9239
9240 /* Add the initializer for this vtable. */
9241 build_vtbl_initializer (binfo, orig_binfo, t, rtti_binfo,
9242 &non_fn_entries, l);
9243
9244 /* Figure out the position to which the VPTR should point. */
9245 vtbl = build1 (ADDR_EXPR, vtbl_ptr_type_node, orig_vtbl);
9246 index = size_binop (MULT_EXPR,
9247 TYPE_SIZE_UNIT (vtable_entry_type),
9248 size_int (non_fn_entries + n_inits));
9249 vtbl = fold_build_pointer_plus (vtbl, index);
9250 }
9251
9252 if (ctor_vtbl_p)
9253 /* For a construction vtable, we can't overwrite BINFO_VTABLE.
9254 So, we make a TREE_LIST. Later, dfs_fixup_binfo_vtbls will
9255 straighten this out. */
9256 BINFO_VTABLE (binfo) = tree_cons (rtti_binfo, vtbl, BINFO_VTABLE (binfo));
9257 else if (BINFO_PRIMARY_P (binfo) && BINFO_VIRTUAL_P (binfo))
9258 /* Throw away any unneeded intializers. */
9259 (*l)->truncate (n_inits);
9260 else
9261 /* For an ordinary vtable, set BINFO_VTABLE. */
9262 BINFO_VTABLE (binfo) = vtbl;
9263 }
9264
9265 static GTY(()) tree abort_fndecl_addr;
9266 static GTY(()) tree dvirt_fn;
9267
9268 /* Construct the initializer for BINFO's virtual function table. BINFO
9269 is part of the hierarchy dominated by T. If we're building a
9270 construction vtable, the ORIG_BINFO is the binfo we should use to
9271 find the actual function pointers to put in the vtable - but they
9272 can be overridden on the path to most-derived in the graph that
9273 ORIG_BINFO belongs. Otherwise,
9274 ORIG_BINFO should be the same as BINFO. The RTTI_BINFO is the
9275 BINFO that should be indicated by the RTTI information in the
9276 vtable; it will be a base class of T, rather than T itself, if we
9277 are building a construction vtable.
9278
9279 The value returned is a TREE_LIST suitable for wrapping in a
9280 CONSTRUCTOR to use as the DECL_INITIAL for a vtable. If
9281 NON_FN_ENTRIES_P is not NULL, *NON_FN_ENTRIES_P is set to the
9282 number of non-function entries in the vtable.
9283
9284 It might seem that this function should never be called with a
9285 BINFO for which BINFO_PRIMARY_P holds, the vtable for such a
9286 base is always subsumed by a derived class vtable. However, when
9287 we are building construction vtables, we do build vtables for
9288 primary bases; we need these while the primary base is being
9289 constructed. */
9290
9291 static void
build_vtbl_initializer(tree binfo,tree orig_binfo,tree t,tree rtti_binfo,int * non_fn_entries_p,vec<constructor_elt,va_gc> ** inits)9292 build_vtbl_initializer (tree binfo,
9293 tree orig_binfo,
9294 tree t,
9295 tree rtti_binfo,
9296 int* non_fn_entries_p,
9297 vec<constructor_elt, va_gc> **inits)
9298 {
9299 tree v;
9300 vtbl_init_data vid;
9301 unsigned ix, jx;
9302 tree vbinfo;
9303 vec<tree, va_gc> *vbases;
9304 constructor_elt *e;
9305
9306 /* Initialize VID. */
9307 memset (&vid, 0, sizeof (vid));
9308 vid.binfo = binfo;
9309 vid.derived = t;
9310 vid.rtti_binfo = rtti_binfo;
9311 vid.primary_vtbl_p = SAME_BINFO_TYPE_P (BINFO_TYPE (binfo), t);
9312 vid.ctor_vtbl_p = !SAME_BINFO_TYPE_P (BINFO_TYPE (rtti_binfo), t);
9313 vid.generate_vcall_entries = true;
9314 /* The first vbase or vcall offset is at index -3 in the vtable. */
9315 vid.index = ssize_int(-3 * TARGET_VTABLE_DATA_ENTRY_DISTANCE);
9316
9317 /* Add entries to the vtable for RTTI. */
9318 build_rtti_vtbl_entries (binfo, &vid);
9319
9320 /* Create an array for keeping track of the functions we've
9321 processed. When we see multiple functions with the same
9322 signature, we share the vcall offsets. */
9323 vec_alloc (vid.fns, 32);
9324 /* Add the vcall and vbase offset entries. */
9325 build_vcall_and_vbase_vtbl_entries (binfo, &vid);
9326
9327 /* Clear BINFO_VTABLE_PATH_MARKED; it's set by
9328 build_vbase_offset_vtbl_entries. */
9329 for (vbases = CLASSTYPE_VBASECLASSES (t), ix = 0;
9330 vec_safe_iterate (vbases, ix, &vbinfo); ix++)
9331 BINFO_VTABLE_PATH_MARKED (vbinfo) = 0;
9332
9333 /* If the target requires padding between data entries, add that now. */
9334 if (TARGET_VTABLE_DATA_ENTRY_DISTANCE > 1)
9335 {
9336 int n_entries = vec_safe_length (vid.inits);
9337
9338 vec_safe_grow (vid.inits, TARGET_VTABLE_DATA_ENTRY_DISTANCE * n_entries);
9339
9340 /* Move data entries into their new positions and add padding
9341 after the new positions. Iterate backwards so we don't
9342 overwrite entries that we would need to process later. */
9343 for (ix = n_entries - 1;
9344 vid.inits->iterate (ix, &e);
9345 ix--)
9346 {
9347 int j;
9348 int new_position = (TARGET_VTABLE_DATA_ENTRY_DISTANCE * ix
9349 + (TARGET_VTABLE_DATA_ENTRY_DISTANCE - 1));
9350
9351 (*vid.inits)[new_position] = *e;
9352
9353 for (j = 1; j < TARGET_VTABLE_DATA_ENTRY_DISTANCE; ++j)
9354 {
9355 constructor_elt *f = &(*vid.inits)[new_position - j];
9356 f->index = NULL_TREE;
9357 f->value = build1 (NOP_EXPR, vtable_entry_type,
9358 null_pointer_node);
9359 }
9360 }
9361 }
9362
9363 if (non_fn_entries_p)
9364 *non_fn_entries_p = vec_safe_length (vid.inits);
9365
9366 /* The initializers for virtual functions were built up in reverse
9367 order. Straighten them out and add them to the running list in one
9368 step. */
9369 jx = vec_safe_length (*inits);
9370 vec_safe_grow (*inits, jx + vid.inits->length ());
9371
9372 for (ix = vid.inits->length () - 1;
9373 vid.inits->iterate (ix, &e);
9374 ix--, jx++)
9375 (**inits)[jx] = *e;
9376
9377 /* Go through all the ordinary virtual functions, building up
9378 initializers. */
9379 for (v = BINFO_VIRTUALS (orig_binfo); v; v = TREE_CHAIN (v))
9380 {
9381 tree delta;
9382 tree vcall_index;
9383 tree fn, fn_original;
9384 tree init = NULL_TREE;
9385
9386 fn = BV_FN (v);
9387 fn_original = fn;
9388 if (DECL_THUNK_P (fn))
9389 {
9390 if (!DECL_NAME (fn))
9391 finish_thunk (fn);
9392 if (THUNK_ALIAS (fn))
9393 {
9394 fn = THUNK_ALIAS (fn);
9395 BV_FN (v) = fn;
9396 }
9397 fn_original = THUNK_TARGET (fn);
9398 }
9399
9400 /* If the only definition of this function signature along our
9401 primary base chain is from a lost primary, this vtable slot will
9402 never be used, so just zero it out. This is important to avoid
9403 requiring extra thunks which cannot be generated with the function.
9404
9405 We first check this in update_vtable_entry_for_fn, so we handle
9406 restored primary bases properly; we also need to do it here so we
9407 zero out unused slots in ctor vtables, rather than filling them
9408 with erroneous values (though harmless, apart from relocation
9409 costs). */
9410 if (BV_LOST_PRIMARY (v))
9411 init = size_zero_node;
9412
9413 if (! init)
9414 {
9415 /* Pull the offset for `this', and the function to call, out of
9416 the list. */
9417 delta = BV_DELTA (v);
9418 vcall_index = BV_VCALL_INDEX (v);
9419
9420 gcc_assert (TREE_CODE (delta) == INTEGER_CST);
9421 gcc_assert (TREE_CODE (fn) == FUNCTION_DECL);
9422
9423 /* You can't call an abstract virtual function; it's abstract.
9424 So, we replace these functions with __pure_virtual. */
9425 if (DECL_PURE_VIRTUAL_P (fn_original))
9426 {
9427 fn = abort_fndecl;
9428 if (!TARGET_VTABLE_USES_DESCRIPTORS)
9429 {
9430 if (abort_fndecl_addr == NULL)
9431 abort_fndecl_addr
9432 = fold_convert (vfunc_ptr_type_node,
9433 build_fold_addr_expr (fn));
9434 init = abort_fndecl_addr;
9435 }
9436 }
9437 /* Likewise for deleted virtuals. */
9438 else if (DECL_DELETED_FN (fn_original))
9439 {
9440 if (!dvirt_fn)
9441 {
9442 tree name = get_identifier ("__cxa_deleted_virtual");
9443 dvirt_fn = get_global_binding (name);
9444 if (!dvirt_fn)
9445 dvirt_fn = push_library_fn
9446 (name,
9447 build_function_type_list (void_type_node, NULL_TREE),
9448 NULL_TREE, ECF_NORETURN | ECF_COLD);
9449 }
9450 fn = dvirt_fn;
9451 if (!TARGET_VTABLE_USES_DESCRIPTORS)
9452 init = fold_convert (vfunc_ptr_type_node,
9453 build_fold_addr_expr (fn));
9454 }
9455 else
9456 {
9457 if (!integer_zerop (delta) || vcall_index)
9458 {
9459 fn = make_thunk (fn, /*this_adjusting=*/1,
9460 delta, vcall_index);
9461 if (!DECL_NAME (fn))
9462 finish_thunk (fn);
9463 }
9464 /* Take the address of the function, considering it to be of an
9465 appropriate generic type. */
9466 if (!TARGET_VTABLE_USES_DESCRIPTORS)
9467 init = fold_convert (vfunc_ptr_type_node,
9468 build_fold_addr_expr (fn));
9469 /* Don't refer to a virtual destructor from a constructor
9470 vtable or a vtable for an abstract class, since destroying
9471 an object under construction is undefined behavior and we
9472 don't want it to be considered a candidate for speculative
9473 devirtualization. But do create the thunk for ABI
9474 compliance. */
9475 if (DECL_DESTRUCTOR_P (fn_original)
9476 && (CLASSTYPE_PURE_VIRTUALS (DECL_CONTEXT (fn_original))
9477 || orig_binfo != binfo))
9478 init = size_zero_node;
9479 }
9480 }
9481
9482 /* And add it to the chain of initializers. */
9483 if (TARGET_VTABLE_USES_DESCRIPTORS)
9484 {
9485 int i;
9486 if (init == size_zero_node)
9487 for (i = 0; i < TARGET_VTABLE_USES_DESCRIPTORS; ++i)
9488 CONSTRUCTOR_APPEND_ELT (*inits, size_int (jx++), init);
9489 else
9490 for (i = 0; i < TARGET_VTABLE_USES_DESCRIPTORS; ++i)
9491 {
9492 tree fdesc = build2 (FDESC_EXPR, vfunc_ptr_type_node,
9493 fn, build_int_cst (NULL_TREE, i));
9494 TREE_CONSTANT (fdesc) = 1;
9495
9496 CONSTRUCTOR_APPEND_ELT (*inits, size_int (jx++), fdesc);
9497 }
9498 }
9499 else
9500 CONSTRUCTOR_APPEND_ELT (*inits, size_int (jx++), init);
9501 }
9502 }
9503
9504 /* Adds to vid->inits the initializers for the vbase and vcall
9505 offsets in BINFO, which is in the hierarchy dominated by T. */
9506
9507 static void
build_vcall_and_vbase_vtbl_entries(tree binfo,vtbl_init_data * vid)9508 build_vcall_and_vbase_vtbl_entries (tree binfo, vtbl_init_data* vid)
9509 {
9510 tree b;
9511
9512 /* If this is a derived class, we must first create entries
9513 corresponding to the primary base class. */
9514 b = get_primary_binfo (binfo);
9515 if (b)
9516 build_vcall_and_vbase_vtbl_entries (b, vid);
9517
9518 /* Add the vbase entries for this base. */
9519 build_vbase_offset_vtbl_entries (binfo, vid);
9520 /* Add the vcall entries for this base. */
9521 build_vcall_offset_vtbl_entries (binfo, vid);
9522 }
9523
9524 /* Returns the initializers for the vbase offset entries in the vtable
9525 for BINFO (which is part of the class hierarchy dominated by T), in
9526 reverse order. VBASE_OFFSET_INDEX gives the vtable index
9527 where the next vbase offset will go. */
9528
9529 static void
build_vbase_offset_vtbl_entries(tree binfo,vtbl_init_data * vid)9530 build_vbase_offset_vtbl_entries (tree binfo, vtbl_init_data* vid)
9531 {
9532 tree vbase;
9533 tree t;
9534 tree non_primary_binfo;
9535
9536 /* If there are no virtual baseclasses, then there is nothing to
9537 do. */
9538 if (!CLASSTYPE_VBASECLASSES (BINFO_TYPE (binfo)))
9539 return;
9540
9541 t = vid->derived;
9542
9543 /* We might be a primary base class. Go up the inheritance hierarchy
9544 until we find the most derived class of which we are a primary base:
9545 it is the offset of that which we need to use. */
9546 non_primary_binfo = binfo;
9547 while (BINFO_INHERITANCE_CHAIN (non_primary_binfo))
9548 {
9549 tree b;
9550
9551 /* If we have reached a virtual base, then it must be a primary
9552 base (possibly multi-level) of vid->binfo, or we wouldn't
9553 have called build_vcall_and_vbase_vtbl_entries for it. But it
9554 might be a lost primary, so just skip down to vid->binfo. */
9555 if (BINFO_VIRTUAL_P (non_primary_binfo))
9556 {
9557 non_primary_binfo = vid->binfo;
9558 break;
9559 }
9560
9561 b = BINFO_INHERITANCE_CHAIN (non_primary_binfo);
9562 if (get_primary_binfo (b) != non_primary_binfo)
9563 break;
9564 non_primary_binfo = b;
9565 }
9566
9567 /* Go through the virtual bases, adding the offsets. */
9568 for (vbase = TYPE_BINFO (BINFO_TYPE (binfo));
9569 vbase;
9570 vbase = TREE_CHAIN (vbase))
9571 {
9572 tree b;
9573 tree delta;
9574
9575 if (!BINFO_VIRTUAL_P (vbase))
9576 continue;
9577
9578 /* Find the instance of this virtual base in the complete
9579 object. */
9580 b = copied_binfo (vbase, binfo);
9581
9582 /* If we've already got an offset for this virtual base, we
9583 don't need another one. */
9584 if (BINFO_VTABLE_PATH_MARKED (b))
9585 continue;
9586 BINFO_VTABLE_PATH_MARKED (b) = 1;
9587
9588 /* Figure out where we can find this vbase offset. */
9589 delta = size_binop (MULT_EXPR,
9590 vid->index,
9591 fold_convert (ssizetype,
9592 TYPE_SIZE_UNIT (vtable_entry_type)));
9593 if (vid->primary_vtbl_p)
9594 BINFO_VPTR_FIELD (b) = delta;
9595
9596 if (binfo != TYPE_BINFO (t))
9597 /* The vbase offset had better be the same. */
9598 gcc_assert (tree_int_cst_equal (delta, BINFO_VPTR_FIELD (vbase)));
9599
9600 /* The next vbase will come at a more negative offset. */
9601 vid->index = size_binop (MINUS_EXPR, vid->index,
9602 ssize_int (TARGET_VTABLE_DATA_ENTRY_DISTANCE));
9603
9604 /* The initializer is the delta from BINFO to this virtual base.
9605 The vbase offsets go in reverse inheritance-graph order, and
9606 we are walking in inheritance graph order so these end up in
9607 the right order. */
9608 delta = size_diffop_loc (input_location,
9609 BINFO_OFFSET (b), BINFO_OFFSET (non_primary_binfo));
9610
9611 CONSTRUCTOR_APPEND_ELT (vid->inits, NULL_TREE,
9612 fold_build1_loc (input_location, NOP_EXPR,
9613 vtable_entry_type, delta));
9614 }
9615 }
9616
9617 /* Adds the initializers for the vcall offset entries in the vtable
9618 for BINFO (which is part of the class hierarchy dominated by VID->DERIVED)
9619 to VID->INITS. */
9620
9621 static void
build_vcall_offset_vtbl_entries(tree binfo,vtbl_init_data * vid)9622 build_vcall_offset_vtbl_entries (tree binfo, vtbl_init_data* vid)
9623 {
9624 /* We only need these entries if this base is a virtual base. We
9625 compute the indices -- but do not add to the vtable -- when
9626 building the main vtable for a class. */
9627 if (binfo == TYPE_BINFO (vid->derived)
9628 || (BINFO_VIRTUAL_P (binfo)
9629 /* If BINFO is RTTI_BINFO, then (since BINFO does not
9630 correspond to VID->DERIVED), we are building a primary
9631 construction virtual table. Since this is a primary
9632 virtual table, we do not need the vcall offsets for
9633 BINFO. */
9634 && binfo != vid->rtti_binfo))
9635 {
9636 /* We need a vcall offset for each of the virtual functions in this
9637 vtable. For example:
9638
9639 class A { virtual void f (); };
9640 class B1 : virtual public A { virtual void f (); };
9641 class B2 : virtual public A { virtual void f (); };
9642 class C: public B1, public B2 { virtual void f (); };
9643
9644 A C object has a primary base of B1, which has a primary base of A. A
9645 C also has a secondary base of B2, which no longer has a primary base
9646 of A. So the B2-in-C construction vtable needs a secondary vtable for
9647 A, which will adjust the A* to a B2* to call f. We have no way of
9648 knowing what (or even whether) this offset will be when we define B2,
9649 so we store this "vcall offset" in the A sub-vtable and look it up in
9650 a "virtual thunk" for B2::f.
9651
9652 We need entries for all the functions in our primary vtable and
9653 in our non-virtual bases' secondary vtables. */
9654 vid->vbase = binfo;
9655 /* If we are just computing the vcall indices -- but do not need
9656 the actual entries -- not that. */
9657 if (!BINFO_VIRTUAL_P (binfo))
9658 vid->generate_vcall_entries = false;
9659 /* Now, walk through the non-virtual bases, adding vcall offsets. */
9660 add_vcall_offset_vtbl_entries_r (binfo, vid);
9661 }
9662 }
9663
9664 /* Build vcall offsets, starting with those for BINFO. */
9665
9666 static void
add_vcall_offset_vtbl_entries_r(tree binfo,vtbl_init_data * vid)9667 add_vcall_offset_vtbl_entries_r (tree binfo, vtbl_init_data* vid)
9668 {
9669 int i;
9670 tree primary_binfo;
9671 tree base_binfo;
9672
9673 /* Don't walk into virtual bases -- except, of course, for the
9674 virtual base for which we are building vcall offsets. Any
9675 primary virtual base will have already had its offsets generated
9676 through the recursion in build_vcall_and_vbase_vtbl_entries. */
9677 if (BINFO_VIRTUAL_P (binfo) && vid->vbase != binfo)
9678 return;
9679
9680 /* If BINFO has a primary base, process it first. */
9681 primary_binfo = get_primary_binfo (binfo);
9682 if (primary_binfo)
9683 add_vcall_offset_vtbl_entries_r (primary_binfo, vid);
9684
9685 /* Add BINFO itself to the list. */
9686 add_vcall_offset_vtbl_entries_1 (binfo, vid);
9687
9688 /* Scan the non-primary bases of BINFO. */
9689 for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
9690 if (base_binfo != primary_binfo)
9691 add_vcall_offset_vtbl_entries_r (base_binfo, vid);
9692 }
9693
9694 /* Called from build_vcall_offset_vtbl_entries_r. */
9695
9696 static void
add_vcall_offset_vtbl_entries_1(tree binfo,vtbl_init_data * vid)9697 add_vcall_offset_vtbl_entries_1 (tree binfo, vtbl_init_data* vid)
9698 {
9699 /* Make entries for the rest of the virtuals. */
9700 tree orig_fn;
9701
9702 /* The ABI requires that the methods be processed in declaration
9703 order. */
9704 for (orig_fn = TYPE_FIELDS (BINFO_TYPE (binfo));
9705 orig_fn;
9706 orig_fn = DECL_CHAIN (orig_fn))
9707 if (TREE_CODE (orig_fn) == FUNCTION_DECL && DECL_VINDEX (orig_fn))
9708 add_vcall_offset (orig_fn, binfo, vid);
9709 }
9710
9711 /* Add a vcall offset entry for ORIG_FN to the vtable. */
9712
9713 static void
add_vcall_offset(tree orig_fn,tree binfo,vtbl_init_data * vid)9714 add_vcall_offset (tree orig_fn, tree binfo, vtbl_init_data *vid)
9715 {
9716 size_t i;
9717 tree vcall_offset;
9718 tree derived_entry;
9719
9720 /* If there is already an entry for a function with the same
9721 signature as FN, then we do not need a second vcall offset.
9722 Check the list of functions already present in the derived
9723 class vtable. */
9724 FOR_EACH_VEC_SAFE_ELT (vid->fns, i, derived_entry)
9725 {
9726 if (same_signature_p (derived_entry, orig_fn)
9727 /* We only use one vcall offset for virtual destructors,
9728 even though there are two virtual table entries. */
9729 || (DECL_DESTRUCTOR_P (derived_entry)
9730 && DECL_DESTRUCTOR_P (orig_fn)))
9731 return;
9732 }
9733
9734 /* If we are building these vcall offsets as part of building
9735 the vtable for the most derived class, remember the vcall
9736 offset. */
9737 if (vid->binfo == TYPE_BINFO (vid->derived))
9738 {
9739 tree_pair_s elt = {orig_fn, vid->index};
9740 vec_safe_push (CLASSTYPE_VCALL_INDICES (vid->derived), elt);
9741 }
9742
9743 /* The next vcall offset will be found at a more negative
9744 offset. */
9745 vid->index = size_binop (MINUS_EXPR, vid->index,
9746 ssize_int (TARGET_VTABLE_DATA_ENTRY_DISTANCE));
9747
9748 /* Keep track of this function. */
9749 vec_safe_push (vid->fns, orig_fn);
9750
9751 if (vid->generate_vcall_entries)
9752 {
9753 tree base;
9754 tree fn;
9755
9756 /* Find the overriding function. */
9757 fn = find_final_overrider (vid->rtti_binfo, binfo, orig_fn);
9758 if (fn == error_mark_node)
9759 vcall_offset = build_zero_cst (vtable_entry_type);
9760 else
9761 {
9762 base = TREE_VALUE (fn);
9763
9764 /* The vbase we're working on is a primary base of
9765 vid->binfo. But it might be a lost primary, so its
9766 BINFO_OFFSET might be wrong, so we just use the
9767 BINFO_OFFSET from vid->binfo. */
9768 vcall_offset = size_diffop_loc (input_location,
9769 BINFO_OFFSET (base),
9770 BINFO_OFFSET (vid->binfo));
9771 vcall_offset = fold_build1_loc (input_location,
9772 NOP_EXPR, vtable_entry_type,
9773 vcall_offset);
9774 }
9775 /* Add the initializer to the vtable. */
9776 CONSTRUCTOR_APPEND_ELT (vid->inits, NULL_TREE, vcall_offset);
9777 }
9778 }
9779
9780 /* Return vtbl initializers for the RTTI entries corresponding to the
9781 BINFO's vtable. The RTTI entries should indicate the object given
9782 by VID->rtti_binfo. */
9783
9784 static void
build_rtti_vtbl_entries(tree binfo,vtbl_init_data * vid)9785 build_rtti_vtbl_entries (tree binfo, vtbl_init_data* vid)
9786 {
9787 tree b;
9788 tree t;
9789 tree offset;
9790 tree decl;
9791 tree init;
9792
9793 t = BINFO_TYPE (vid->rtti_binfo);
9794
9795 /* To find the complete object, we will first convert to our most
9796 primary base, and then add the offset in the vtbl to that value. */
9797 b = most_primary_binfo (binfo);
9798 offset = size_diffop_loc (input_location,
9799 BINFO_OFFSET (vid->rtti_binfo), BINFO_OFFSET (b));
9800
9801 /* The second entry is the address of the typeinfo object. */
9802 if (flag_rtti)
9803 decl = build_address (get_tinfo_decl (t));
9804 else
9805 decl = integer_zero_node;
9806
9807 /* Convert the declaration to a type that can be stored in the
9808 vtable. */
9809 init = build_nop (vfunc_ptr_type_node, decl);
9810 CONSTRUCTOR_APPEND_ELT (vid->inits, NULL_TREE, init);
9811
9812 /* Add the offset-to-top entry. It comes earlier in the vtable than
9813 the typeinfo entry. Convert the offset to look like a
9814 function pointer, so that we can put it in the vtable. */
9815 init = build_nop (vfunc_ptr_type_node, offset);
9816 CONSTRUCTOR_APPEND_ELT (vid->inits, NULL_TREE, init);
9817 }
9818
9819 /* TRUE iff TYPE is uniquely derived from PARENT. Ignores
9820 accessibility. */
9821
9822 bool
uniquely_derived_from_p(tree parent,tree type)9823 uniquely_derived_from_p (tree parent, tree type)
9824 {
9825 tree base = lookup_base (type, parent, ba_unique, NULL, tf_none);
9826 return base && base != error_mark_node;
9827 }
9828
9829 /* TRUE iff TYPE is publicly & uniquely derived from PARENT. */
9830
9831 bool
publicly_uniquely_derived_p(tree parent,tree type)9832 publicly_uniquely_derived_p (tree parent, tree type)
9833 {
9834 tree base = lookup_base (type, parent, ba_ignore_scope | ba_check,
9835 NULL, tf_none);
9836 return base && base != error_mark_node;
9837 }
9838
9839 /* CTX1 and CTX2 are declaration contexts. Return the innermost common
9840 class between them, if any. */
9841
9842 tree
common_enclosing_class(tree ctx1,tree ctx2)9843 common_enclosing_class (tree ctx1, tree ctx2)
9844 {
9845 if (!TYPE_P (ctx1) || !TYPE_P (ctx2))
9846 return NULL_TREE;
9847 gcc_assert (ctx1 == TYPE_MAIN_VARIANT (ctx1)
9848 && ctx2 == TYPE_MAIN_VARIANT (ctx2));
9849 if (ctx1 == ctx2)
9850 return ctx1;
9851 for (tree t = ctx1; TYPE_P (t); t = TYPE_CONTEXT (t))
9852 TYPE_MARKED_P (t) = true;
9853 tree found = NULL_TREE;
9854 for (tree t = ctx2; TYPE_P (t); t = TYPE_CONTEXT (t))
9855 if (TYPE_MARKED_P (t))
9856 {
9857 found = t;
9858 break;
9859 }
9860 for (tree t = ctx1; TYPE_P (t); t = TYPE_CONTEXT (t))
9861 TYPE_MARKED_P (t) = false;
9862 return found;
9863 }
9864
9865 #include "gt-cp-class.h"
9866