1//===----------------------- private_typeinfo.cpp -------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "private_typeinfo.h"
10
11// The flag _LIBCXX_DYNAMIC_FALLBACK is used to make dynamic_cast more
12// forgiving when type_info's mistakenly have hidden visibility and thus
13// multiple type_infos can exist for a single type.
14//
15// When _LIBCXX_DYNAMIC_FALLBACK is defined, and only in the case where
16// there is a detected inconsistency in the type_info hierarchy during a
17// dynamic_cast, then the equality operation will fall back to using strcmp
18// on type_info names to determine type_info equality.
19//
20// This change happens *only* under dynamic_cast, and only when
21// dynamic_cast is faced with the choice: abort, or possibly give back the
22// wrong answer. If when the dynamic_cast is done with this fallback
23// algorithm and an inconsistency is still detected, dynamic_cast will call
24// abort with an appropriate message.
25//
26// The current implementation of _LIBCXX_DYNAMIC_FALLBACK requires a
27// printf-like function called syslog:
28//
29// void syslog(int facility_priority, const char* format, ...);
30//
31// If you want this functionality but your platform doesn't have syslog,
32// just implement it in terms of fprintf(stderr, ...).
33//
34// _LIBCXX_DYNAMIC_FALLBACK is currently off by default.
35
36
37#include <string.h>
38
39
40#ifdef _LIBCXX_DYNAMIC_FALLBACK
41#include "abort_message.h"
42#include <sys/syslog.h>
43#endif
44
45// On Windows, typeids are different between DLLs and EXEs, so comparing
46// type_info* will work for typeids from the same compiled file but fail
47// for typeids from a DLL and an executable. Among other things, exceptions
48// are not caught by handlers since can_catch() returns false.
49//
50// Defining _LIBCXX_DYNAMIC_FALLBACK does not help since can_catch() calls
51// is_equal() with use_strcmp=false so the string names are not compared.
52
53#ifdef _WIN32
54#include <string.h>
55#endif
56
57static inline
58bool
59is_equal(const std::type_info* x, const std::type_info* y, bool use_strcmp)
60{
61 // Use std::type_info's default comparison unless we've explicitly asked
62 // for strcmp.
63 if (!use_strcmp)
64 return *x == *y;
65 // Still allow pointer equality to short circut.
66 return x == y || strcmp(x->name(), y->name()) == 0;
67}
68
69namespace __cxxabiv1
70{
71
72// __shim_type_info
73
74__shim_type_info::~__shim_type_info()
75{
76}
77
78void __shim_type_info::noop1() const {}
79void __shim_type_info::noop2() const {}
80
81// __fundamental_type_info
82
83// This miraculously (compiler magic) emits the type_info's for:
84// 1. all of the fundamental types
85// 2. pointers to all of the fundamental types
86// 3. pointers to all of the const fundamental types
87__fundamental_type_info::~__fundamental_type_info()
88{
89}
90
91// __array_type_info
92
93__array_type_info::~__array_type_info()
94{
95}
96
97// __function_type_info
98
99__function_type_info::~__function_type_info()
100{
101}
102
103// __enum_type_info
104
105__enum_type_info::~__enum_type_info()
106{
107}
108
109// __class_type_info
110
111__class_type_info::~__class_type_info()
112{
113}
114
115// __si_class_type_info
116
117__si_class_type_info::~__si_class_type_info()
118{
119}
120
121// __vmi_class_type_info
122
123__vmi_class_type_info::~__vmi_class_type_info()
124{
125}
126
127// __pbase_type_info
128
129__pbase_type_info::~__pbase_type_info()
130{
131}
132
133// __pointer_type_info
134
135__pointer_type_info::~__pointer_type_info()
136{
137}
138
139// __pointer_to_member_type_info
140
141__pointer_to_member_type_info::~__pointer_to_member_type_info()
142{
143}
144
145// can_catch
146
147// A handler is a match for an exception object of type E if
148// 1. The handler is of type cv T or cv T& and E and T are the same type
149// (ignoring the top-level cv-qualifiers), or
150// 2. the handler is of type cv T or cv T& and T is an unambiguous public
151// base class of E, or
152// 3. the handler is of type cv1 T* cv2 and E is a pointer type that can be
153// converted to the type of the handler by either or both of
154// A. a standard pointer conversion (4.10) not involving conversions to
155// pointers to private or protected or ambiguous classes
156// B. a qualification conversion
157// 4. the handler is a pointer or pointer to member type and E is
158// std::nullptr_t.
159
160// adjustedPtr:
161//
162// catch (A& a) : adjustedPtr == &a
163// catch (A* a) : adjustedPtr == a
164// catch (A** a) : adjustedPtr == a
165//
166// catch (D2& d2) : adjustedPtr == &d2 (d2 is base class of thrown object)
167// catch (D2* d2) : adjustedPtr == d2
168// catch (D2*& d2) : adjustedPtr == d2
169//
170// catch (...) : adjustedPtr == & of the exception
171//
172// If the thrown type is nullptr_t and the caught type is a pointer to
173// member type, adjustedPtr points to a statically-allocated null pointer
174// representation of that type.
175
176// Handles bullet 1
177bool
178__fundamental_type_info::can_catch(const __shim_type_info* thrown_type,
179 void*&) const
180{
181 return is_equal(this, thrown_type, false);
182}
183
184bool
185__array_type_info::can_catch(const __shim_type_info*, void*&) const
186{
187 // We can get here if someone tries to catch an array by reference.
188 // However if someone tries to throw an array, it immediately gets
189 // converted to a pointer, which will not convert back to an array
190 // at the catch clause. So this can never catch anything.
191 return false;
192}
193
194bool
195__function_type_info::can_catch(const __shim_type_info*, void*&) const
196{
197 // We can get here if someone tries to catch a function by reference.
198 // However if someone tries to throw a function, it immediately gets
199 // converted to a pointer, which will not convert back to a function
200 // at the catch clause. So this can never catch anything.
201 return false;
202}
203
204// Handles bullet 1
205bool
206__enum_type_info::can_catch(const __shim_type_info* thrown_type,
207 void*&) const
208{
209 return is_equal(this, thrown_type, false);
210}
211
212#ifdef __clang__
213#pragma clang diagnostic push
214#pragma clang diagnostic ignored "-Wmissing-field-initializers"
215#endif
216
217// Handles bullets 1 and 2
218bool
219__class_type_info::can_catch(const __shim_type_info* thrown_type,
220 void*& adjustedPtr) const
221{
222 // bullet 1
223 if (is_equal(this, thrown_type, false))
224 return true;
225 const __class_type_info* thrown_class_type =
226 dynamic_cast<const __class_type_info*>(thrown_type);
227 if (thrown_class_type == 0)
228 return false;
229 // bullet 2
230 __dynamic_cast_info info = {thrown_class_type, 0, this, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,};
231 info.number_of_dst_type = 1;
232 thrown_class_type->has_unambiguous_public_base(&info, adjustedPtr, public_path);
233 if (info.path_dst_ptr_to_static_ptr == public_path)
234 {
235 adjustedPtr = const_cast<void*>(info.dst_ptr_leading_to_static_ptr);
236 return true;
237 }
238 return false;
239}
240
241#ifdef __clang__
242#pragma clang diagnostic pop
243#endif
244
245void
246__class_type_info::process_found_base_class(__dynamic_cast_info* info,
247 void* adjustedPtr,
248 int path_below) const
249{
250 if (info->dst_ptr_leading_to_static_ptr == 0)
251 {
252 // First time here
253 info->dst_ptr_leading_to_static_ptr = adjustedPtr;
254 info->path_dst_ptr_to_static_ptr = path_below;
255 info->number_to_static_ptr = 1;
256 }
257 else if (info->dst_ptr_leading_to_static_ptr == adjustedPtr)
258 {
259 // We've been here before. Update path to "most public"
260 if (info->path_dst_ptr_to_static_ptr == not_public_path)
261 info->path_dst_ptr_to_static_ptr = path_below;
262 }
263 else
264 {
265 // We've detected an ambiguous cast from (thrown_class_type, adjustedPtr)
266 // to a static_type
267 info->number_to_static_ptr += 1;
268 info->path_dst_ptr_to_static_ptr = not_public_path;
269 info->search_done = true;
270 }
271}
272
273void
274__class_type_info::has_unambiguous_public_base(__dynamic_cast_info* info,
275 void* adjustedPtr,
276 int path_below) const
277{
278 if (is_equal(this, info->static_type, false))
279 process_found_base_class(info, adjustedPtr, path_below);
280}
281
282void
283__si_class_type_info::has_unambiguous_public_base(__dynamic_cast_info* info,
284 void* adjustedPtr,
285 int path_below) const
286{
287 if (is_equal(this, info->static_type, false))
288 process_found_base_class(info, adjustedPtr, path_below);
289 else
290 __base_type->has_unambiguous_public_base(info, adjustedPtr, path_below);
291}
292
293void
294__base_class_type_info::has_unambiguous_public_base(__dynamic_cast_info* info,
295 void* adjustedPtr,
296 int path_below) const
297{
298 ptrdiff_t offset_to_base = 0;
299 if (adjustedPtr != nullptr)
300 {
301 offset_to_base = __offset_flags >> __offset_shift;
302 if (__offset_flags & __virtual_mask)
303 {
304 const char* vtable = *static_cast<const char*const*>(adjustedPtr);
305 offset_to_base = *reinterpret_cast<const ptrdiff_t*>(vtable + offset_to_base);
306 }
307 }
308 __base_type->has_unambiguous_public_base(
309 info,
310 static_cast<char*>(adjustedPtr) + offset_to_base,
311 (__offset_flags & __public_mask) ? path_below : not_public_path);
312}
313
314void
315__vmi_class_type_info::has_unambiguous_public_base(__dynamic_cast_info* info,
316 void* adjustedPtr,
317 int path_below) const
318{
319 if (is_equal(this, info->static_type, false))
320 process_found_base_class(info, adjustedPtr, path_below);
321 else
322 {
323 typedef const __base_class_type_info* Iter;
324 const Iter e = __base_info + __base_count;
325 Iter p = __base_info;
326 p->has_unambiguous_public_base(info, adjustedPtr, path_below);
327 if (++p < e)
328 {
329 do
330 {
331 p->has_unambiguous_public_base(info, adjustedPtr, path_below);
332 if (info->search_done)
333 break;
334 } while (++p < e);
335 }
336 }
337}
338
339// Handles bullet 1 for both pointers and member pointers
340bool
341__pbase_type_info::can_catch(const __shim_type_info* thrown_type,
342 void*&) const
343{
344 bool use_strcmp = this->__flags & (__incomplete_class_mask |
345 __incomplete_mask);
346 if (!use_strcmp) {
347 const __pbase_type_info* thrown_pbase = dynamic_cast<const __pbase_type_info*>(
348 thrown_type);
349 if (!thrown_pbase) return false;
350 use_strcmp = thrown_pbase->__flags & (__incomplete_class_mask |
351 __incomplete_mask);
352 }
353 return is_equal(this, thrown_type, use_strcmp);
354}
355
356#ifdef __clang__
357#pragma clang diagnostic push
358#pragma clang diagnostic ignored "-Wmissing-field-initializers"
359#endif
360
361// Handles bullets 1, 3 and 4
362// NOTE: It might not be safe to adjust the pointer if it is not not a pointer
363// type. Only adjust the pointer after we know it is safe to do so.
364bool
365__pointer_type_info::can_catch(const __shim_type_info* thrown_type,
366 void*& adjustedPtr) const
367{
368 // bullet 4
369 if (is_equal(thrown_type, &typeid(std::nullptr_t), false)) {
370 adjustedPtr = nullptr;
371 return true;
372 }
373
374 // bullet 1
375 if (__pbase_type_info::can_catch(thrown_type, adjustedPtr)) {
376 if (adjustedPtr != NULL)
377 adjustedPtr = *static_cast<void**>(adjustedPtr);
378 return true;
379 }
380 // bullet 3
381 const __pointer_type_info* thrown_pointer_type =
382 dynamic_cast<const __pointer_type_info*>(thrown_type);
383 if (thrown_pointer_type == 0)
384 return false;
385 // Do the dereference adjustment
386 if (adjustedPtr != NULL)
387 adjustedPtr = *static_cast<void**>(adjustedPtr);
388 // bullet 3B and 3C
389 if (thrown_pointer_type->__flags & ~__flags & __no_remove_flags_mask)
390 return false;
391 if (__flags & ~thrown_pointer_type->__flags & __no_add_flags_mask)
392 return false;
393 if (is_equal(__pointee, thrown_pointer_type->__pointee, false))
394 return true;
395 // bullet 3A
396 if (is_equal(__pointee, &typeid(void), false)) {
397 // pointers to functions cannot be converted to void*.
398 // pointers to member functions are not handled here.
399 const __function_type_info* thrown_function =
400 dynamic_cast<const __function_type_info*>(thrown_pointer_type->__pointee);
401 return (thrown_function == nullptr);
402 }
403 // Handle pointer to pointer
404 const __pointer_type_info* nested_pointer_type =
405 dynamic_cast<const __pointer_type_info*>(__pointee);
406 if (nested_pointer_type) {
407 if (~__flags & __const_mask) return false;
408 return nested_pointer_type->can_catch_nested(thrown_pointer_type->__pointee);
409 }
410
411 // Handle pointer to pointer to member
412 const __pointer_to_member_type_info* member_ptr_type =
413 dynamic_cast<const __pointer_to_member_type_info*>(__pointee);
414 if (member_ptr_type) {
415 if (~__flags & __const_mask) return false;
416 return member_ptr_type->can_catch_nested(thrown_pointer_type->__pointee);
417 }
418
419 // Handle pointer to class type
420 const __class_type_info* catch_class_type =
421 dynamic_cast<const __class_type_info*>(__pointee);
422 if (catch_class_type == 0)
423 return false;
424 const __class_type_info* thrown_class_type =
425 dynamic_cast<const __class_type_info*>(thrown_pointer_type->__pointee);
426 if (thrown_class_type == 0)
427 return false;
428 __dynamic_cast_info info = {thrown_class_type, 0, catch_class_type, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,};
429 info.number_of_dst_type = 1;
430 thrown_class_type->has_unambiguous_public_base(&info, adjustedPtr, public_path);
431 if (info.path_dst_ptr_to_static_ptr == public_path)
432 {
433 if (adjustedPtr != NULL)
434 adjustedPtr = const_cast<void*>(info.dst_ptr_leading_to_static_ptr);
435 return true;
436 }
437 return false;
438}
439
440bool __pointer_type_info::can_catch_nested(
441 const __shim_type_info* thrown_type) const
442{
443 const __pointer_type_info* thrown_pointer_type =
444 dynamic_cast<const __pointer_type_info*>(thrown_type);
445 if (thrown_pointer_type == 0)
446 return false;
447 // bullet 3B
448 if (thrown_pointer_type->__flags & ~__flags)
449 return false;
450 if (is_equal(__pointee, thrown_pointer_type->__pointee, false))
451 return true;
452 // If the pointed to types differ then the catch type must be const
453 // qualified.
454 if (~__flags & __const_mask)
455 return false;
456
457 // Handle pointer to pointer
458 const __pointer_type_info* nested_pointer_type =
459 dynamic_cast<const __pointer_type_info*>(__pointee);
460 if (nested_pointer_type) {
461 return nested_pointer_type->can_catch_nested(
462 thrown_pointer_type->__pointee);
463 }
464
465 // Handle pointer to pointer to member
466 const __pointer_to_member_type_info* member_ptr_type =
467 dynamic_cast<const __pointer_to_member_type_info*>(__pointee);
468 if (member_ptr_type) {
469 return member_ptr_type->can_catch_nested(thrown_pointer_type->__pointee);
470 }
471
472 return false;
473}
474
475bool __pointer_to_member_type_info::can_catch(
476 const __shim_type_info* thrown_type, void*& adjustedPtr) const {
477 // bullet 4
478 if (is_equal(thrown_type, &typeid(std::nullptr_t), false)) {
479 // We assume that the pointer to member representation is the same for
480 // all pointers to data members and for all pointers to member functions.
481 struct X {};
482 if (dynamic_cast<const __function_type_info*>(__pointee)) {
483 static int (X::*const null_ptr_rep)() = nullptr;
484 adjustedPtr = const_cast<int (X::**)()>(&null_ptr_rep);
485 } else {
486 static int X::*const null_ptr_rep = nullptr;
487 adjustedPtr = const_cast<int X::**>(&null_ptr_rep);
488 }
489 return true;
490 }
491
492 // bullet 1
493 if (__pbase_type_info::can_catch(thrown_type, adjustedPtr))
494 return true;
495
496 const __pointer_to_member_type_info* thrown_pointer_type =
497 dynamic_cast<const __pointer_to_member_type_info*>(thrown_type);
498 if (thrown_pointer_type == 0)
499 return false;
500 if (thrown_pointer_type->__flags & ~__flags & __no_remove_flags_mask)
501 return false;
502 if (__flags & ~thrown_pointer_type->__flags & __no_add_flags_mask)
503 return false;
504 if (!is_equal(__pointee, thrown_pointer_type->__pointee, false))
505 return false;
506 if (is_equal(__context, thrown_pointer_type->__context, false))
507 return true;
508
509 // [except.handle] does not allow the pointer-to-member conversions mentioned
510 // in [mem.conv] to take place. For this reason we don't check Derived->Base
511 // for Derived->Base conversions.
512
513 return false;
514}
515
516bool __pointer_to_member_type_info::can_catch_nested(
517 const __shim_type_info* thrown_type) const
518{
519 const __pointer_to_member_type_info* thrown_member_ptr_type =
520 dynamic_cast<const __pointer_to_member_type_info*>(thrown_type);
521 if (thrown_member_ptr_type == 0)
522 return false;
523 if (~__flags & thrown_member_ptr_type->__flags)
524 return false;
525 if (!is_equal(__pointee, thrown_member_ptr_type->__pointee, false))
526 return false;
527 if (!is_equal(__context, thrown_member_ptr_type->__context, false))
528 return false;
529 return true;
530}
531
532#ifdef __clang__
533#pragma clang diagnostic pop
534#endif
535
536#ifdef __clang__
537#pragma clang diagnostic push
538#pragma clang diagnostic ignored "-Wmissing-field-initializers"
539#endif
540
541// __dynamic_cast
542
543// static_ptr: pointer to an object of type static_type; nonnull, and since the
544// object is polymorphic, *(void**)static_ptr is a virtual table pointer.
545// static_ptr is &v in the expression dynamic_cast<T>(v).
546// static_type: static type of the object pointed to by static_ptr.
547// dst_type: destination type of the cast (the "T" in "dynamic_cast<T>(v)").
548// src2dst_offset: a static hint about the location of the
549// source subobject with respect to the complete object;
550// special negative values are:
551// -1: no hint
552// -2: static_type is not a public base of dst_type
553// -3: static_type is a multiple public base type but never a
554// virtual base type
555// otherwise, the static_type type is a unique public nonvirtual
556// base type of dst_type at offset src2dst_offset from the
557// origin of dst_type.
558//
559// (dynamic_ptr, dynamic_type) are the run time type of the complete object
560// referred to by static_ptr and a pointer to it. These can be found from
561// static_ptr for polymorphic types.
562// static_type is guaranteed to be a polymorphic type.
563//
564// (dynamic_ptr, dynamic_type) is the root of a DAG that grows upward. Each
565// node of the tree represents a base class/object of its parent (or parents) below.
566// Each node is uniquely represented by a pointer to the object, and a pointer
567// to a type_info - its type. Different nodes may have the same pointer and
568// different nodes may have the same type. But only one node has a specific
569// (pointer-value, type) pair. In C++ two objects of the same type can not
570// share the same address.
571//
572// There are two flavors of nodes which have the type dst_type:
573// 1. Those that are derived from (below) (static_ptr, static_type).
574// 2. Those that are not derived from (below) (static_ptr, static_type).
575//
576// Invariants of the DAG:
577//
578// There is at least one path from the root (dynamic_ptr, dynamic_type) to
579// the node (static_ptr, static_type). This path may or may not be public.
580// There may be more than one such path (some public some not). Such a path may
581// or may not go through a node having type dst_type.
582//
583// No node of type T appears above a node of the same type. That means that
584// there is only one node with dynamic_type. And if dynamic_type == dst_type,
585// then there is only one dst_type in the DAG.
586//
587// No node of type dst_type appears above a node of type static_type. Such
588// DAG's are possible in C++, but the compiler computes those dynamic_casts at
589// compile time, and only calls __dynamic_cast when dst_type lies below
590// static_type in the DAG.
591//
592// dst_type != static_type: The compiler computes the dynamic_cast in this case too.
593// dynamic_type != static_type: The compiler computes the dynamic_cast in this case too.
594//
595// Returns:
596//
597// If there is exactly one dst_type of flavor 1, and
598// If there is a public path from that dst_type to (static_ptr, static_type), or
599// If there are 0 dst_types of flavor 2, and there is a public path from
600// (dynamic_ptr, dynamic_type) to (static_ptr, static_type) and a public
601// path from (dynamic_ptr, dynamic_type) to the one dst_type, then return
602// a pointer to that dst_type.
603// Else if there are 0 dst_types of flavor 1 and exactly 1 dst_type of flavor 2, and
604// if there is a public path from (dynamic_ptr, dynamic_type) to
605// (static_ptr, static_type) and a public path from (dynamic_ptr, dynamic_type)
606// to the one dst_type, then return a pointer to that one dst_type.
607// Else return nullptr.
608//
609// If dynamic_type == dst_type, then the above algorithm collapses to the
610// following cheaper algorithm:
611//
612// If there is a public path from (dynamic_ptr, dynamic_type) to
613// (static_ptr, static_type), then return dynamic_ptr.
614// Else return nullptr.
615
616extern "C" _LIBCXXABI_FUNC_VIS void *
617__dynamic_cast(const void *static_ptr, const __class_type_info *static_type,
618 const __class_type_info *dst_type,
619 std::ptrdiff_t src2dst_offset) {
620 // Possible future optimization: Take advantage of src2dst_offset
621 // Currently clang always sets src2dst_offset to -1 (no hint).
622
623 // Get (dynamic_ptr, dynamic_type) from static_ptr
624 void **vtable = *static_cast<void ** const *>(static_ptr);
625 ptrdiff_t offset_to_derived = reinterpret_cast<ptrdiff_t>(vtable[-2]);
626 const void* dynamic_ptr = static_cast<const char*>(static_ptr) + offset_to_derived;
627 const __class_type_info* dynamic_type = static_cast<const __class_type_info*>(vtable[-1]);
628
629 // Initialize answer to nullptr. This will be changed from the search
630 // results if a non-null answer is found. Regardless, this is what will
631 // be returned.
632 const void* dst_ptr = 0;
633 // Initialize info struct for this search.
634 __dynamic_cast_info info = {dst_type, static_ptr, static_type, src2dst_offset, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,};
635
636 // Find out if we can use a giant short cut in the search
637 if (is_equal(dynamic_type, dst_type, false))
638 {
639 // Using giant short cut. Add that information to info.
640 info.number_of_dst_type = 1;
641 // Do the search
642 dynamic_type->search_above_dst(&info, dynamic_ptr, dynamic_ptr, public_path, false);
643#ifdef _LIBCXX_DYNAMIC_FALLBACK
644 // The following if should always be false because we should definitely
645 // find (static_ptr, static_type), either on a public or private path
646 if (info.path_dst_ptr_to_static_ptr == unknown)
647 {
648 // We get here only if there is some kind of visibility problem
649 // in client code.
650 syslog(LOG_ERR, "dynamic_cast error 1: Both of the following type_info's "
651 "should have public visibility. At least one of them is hidden. %s"
652 ", %s.\n", static_type->name(), dynamic_type->name());
653 // Redo the search comparing type_info's using strcmp
654 info = {dst_type, static_ptr, static_type, src2dst_offset, 0};
655 info.number_of_dst_type = 1;
656 dynamic_type->search_above_dst(&info, dynamic_ptr, dynamic_ptr, public_path, true);
657 }
658#endif // _LIBCXX_DYNAMIC_FALLBACK
659 // Query the search.
660 if (info.path_dst_ptr_to_static_ptr == public_path)
661 dst_ptr = dynamic_ptr;
662 }
663 else
664 {
665 // Not using giant short cut. Do the search
666 dynamic_type->search_below_dst(&info, dynamic_ptr, public_path, false);
667 #ifdef _LIBCXX_DYNAMIC_FALLBACK
668 // The following if should always be false because we should definitely
669 // find (static_ptr, static_type), either on a public or private path
670 if (info.path_dst_ptr_to_static_ptr == unknown &&
671 info.path_dynamic_ptr_to_static_ptr == unknown)
672 {
673 syslog(LOG_ERR, "dynamic_cast error 2: One or more of the following type_info's "
674 "has hidden visibility or is defined in more than one translation "
675 "unit. They should all have public visibility. "
676 "%s, %s, %s.\n", static_type->name(), dynamic_type->name(),
677 dst_type->name());
678 // Redo the search comparing type_info's using strcmp
679 info = {dst_type, static_ptr, static_type, src2dst_offset, 0};
680 dynamic_type->search_below_dst(&info, dynamic_ptr, public_path, true);
681 }
682#endif // _LIBCXX_DYNAMIC_FALLBACK
683 // Query the search.
684 switch (info.number_to_static_ptr)
685 {
686 case 0:
687 if (info.number_to_dst_ptr == 1 &&
688 info.path_dynamic_ptr_to_static_ptr == public_path &&
689 info.path_dynamic_ptr_to_dst_ptr == public_path)
690 dst_ptr = info.dst_ptr_not_leading_to_static_ptr;
691 break;
692 case 1:
693 if (info.path_dst_ptr_to_static_ptr == public_path ||
694 (
695 info.number_to_dst_ptr == 0 &&
696 info.path_dynamic_ptr_to_static_ptr == public_path &&
697 info.path_dynamic_ptr_to_dst_ptr == public_path
698 )
699 )
700 dst_ptr = info.dst_ptr_leading_to_static_ptr;
701 break;
702 }
703 }
704 return const_cast<void*>(dst_ptr);
705}
706
707#ifdef __clang__
708#pragma clang diagnostic pop
709#endif
710
711// Call this function when you hit a static_type which is a base (above) a dst_type.
712// Let caller know you hit a static_type. But only start recording details if
713// this is (static_ptr, static_type) -- the node we are casting from.
714// If this is (static_ptr, static_type)
715// Record the path (public or not) from the dst_type to here. There may be
716// multiple paths from the same dst_type to here, record the "most public" one.
717// Record the dst_ptr as pointing to (static_ptr, static_type).
718// If more than one (dst_ptr, dst_type) points to (static_ptr, static_type),
719// then mark this dyanmic_cast as ambiguous and stop the search.
720void
721__class_type_info::process_static_type_above_dst(__dynamic_cast_info* info,
722 const void* dst_ptr,
723 const void* current_ptr,
724 int path_below) const
725{
726 // Record that we found a static_type
727 info->found_any_static_type = true;
728 if (current_ptr == info->static_ptr)
729 {
730 // Record that we found (static_ptr, static_type)
731 info->found_our_static_ptr = true;
732 if (info->dst_ptr_leading_to_static_ptr == 0)
733 {
734 // First time here
735 info->dst_ptr_leading_to_static_ptr = dst_ptr;
736 info->path_dst_ptr_to_static_ptr = path_below;
737 info->number_to_static_ptr = 1;
738 // If there is only one dst_type in the entire tree and the path from
739 // there to here is public then we are done!
740 if (info->number_of_dst_type == 1 && info->path_dst_ptr_to_static_ptr == public_path)
741 info->search_done = true;
742 }
743 else if (info->dst_ptr_leading_to_static_ptr == dst_ptr)
744 {
745 // We've been here before. Update path to "most public"
746 if (info->path_dst_ptr_to_static_ptr == not_public_path)
747 info->path_dst_ptr_to_static_ptr = path_below;
748 // If there is only one dst_type in the entire tree and the path from
749 // there to here is public then we are done!
750 if (info->number_of_dst_type == 1 && info->path_dst_ptr_to_static_ptr == public_path)
751 info->search_done = true;
752 }
753 else
754 {
755 // We've detected an ambiguous cast from (static_ptr, static_type)
756 // to a dst_type
757 info->number_to_static_ptr += 1;
758 info->search_done = true;
759 }
760 }
761}
762
763// Call this function when you hit a static_type which is not a base (above) a dst_type.
764// If this is (static_ptr, static_type)
765// Record the path (public or not) from (dynamic_ptr, dynamic_type) to here. There may be
766// multiple paths from (dynamic_ptr, dynamic_type) to here, record the "most public" one.
767void
768__class_type_info::process_static_type_below_dst(__dynamic_cast_info* info,
769 const void* current_ptr,
770 int path_below) const
771{
772 if (current_ptr == info->static_ptr)
773 {
774 // Record the most public path from (dynamic_ptr, dynamic_type) to
775 // (static_ptr, static_type)
776 if (info->path_dynamic_ptr_to_static_ptr != public_path)
777 info->path_dynamic_ptr_to_static_ptr = path_below;
778 }
779}
780
781// Call this function when searching below a dst_type node. This function searches
782// for a path to (static_ptr, static_type) and for paths to one or more dst_type nodes.
783// If it finds a static_type node, there is no need to further search base classes
784// above.
785// If it finds a dst_type node it should search base classes using search_above_dst
786// to find out if this dst_type points to (static_ptr, static_type) or not.
787// Either way, the dst_type is recorded as one of two "flavors": one that does
788// or does not point to (static_ptr, static_type).
789// If this is neither a static_type nor a dst_type node, continue searching
790// base classes above.
791// All the hoopla surrounding the search code is doing nothing but looking for
792// excuses to stop the search prematurely (break out of the for-loop). That is,
793// the algorithm below is simply an optimization of this:
794// void
795// __vmi_class_type_info::search_below_dst(__dynamic_cast_info* info,
796// const void* current_ptr,
797// int path_below) const
798// {
799// typedef const __base_class_type_info* Iter;
800// if (this == info->static_type)
801// process_static_type_below_dst(info, current_ptr, path_below);
802// else if (this == info->dst_type)
803// {
804// // Record the most public access path that got us here
805// if (info->path_dynamic_ptr_to_dst_ptr != public_path)
806// info->path_dynamic_ptr_to_dst_ptr = path_below;
807// bool does_dst_type_point_to_our_static_type = false;
808// for (Iter p = __base_info, e= __base_info + __base_count; p < e; ++p)
809// {
810// p->search_above_dst(info, current_ptr, current_ptr, public_path);
811// if (info->found_our_static_ptr)
812// does_dst_type_point_to_our_static_type = true;
813// // break out early here if you can detect it doesn't matter if you do
814// }
815// if (!does_dst_type_point_to_our_static_type)
816// {
817// // We found a dst_type that doesn't point to (static_ptr, static_type)
818// // So record the address of this dst_ptr and increment the
819// // count of the number of such dst_types found in the tree.
820// info->dst_ptr_not_leading_to_static_ptr = current_ptr;
821// info->number_to_dst_ptr += 1;
822// }
823// }
824// else
825// {
826// // This is not a static_type and not a dst_type.
827// for (Iter p = __base_info, e = __base_info + __base_count; p < e; ++p)
828// {
829// p->search_below_dst(info, current_ptr, public_path);
830// // break out early here if you can detect it doesn't matter if you do
831// }
832// }
833// }
834void
835__vmi_class_type_info::search_below_dst(__dynamic_cast_info* info,
836 const void* current_ptr,
837 int path_below,
838 bool use_strcmp) const
839{
840 typedef const __base_class_type_info* Iter;
841 if (is_equal(this, info->static_type, use_strcmp))
842 process_static_type_below_dst(info, current_ptr, path_below);
843 else if (is_equal(this, info->dst_type, use_strcmp))
844 {
845 // We've been here before if we've recorded current_ptr in one of these
846 // two places:
847 if (current_ptr == info->dst_ptr_leading_to_static_ptr ||
848 current_ptr == info->dst_ptr_not_leading_to_static_ptr)
849 {
850 // We've seen this node before, and therefore have already searched
851 // its base classes above.
852 // Update path to here that is "most public".
853 if (path_below == public_path)
854 info->path_dynamic_ptr_to_dst_ptr = public_path;
855 }
856 else // We have haven't been here before
857 {
858 // Record the access path that got us here
859 // If there is more than one dst_type this path doesn't matter.
860 info->path_dynamic_ptr_to_dst_ptr = path_below;
861 bool does_dst_type_point_to_our_static_type = false;
862 // Only search above here if dst_type derives from static_type, or
863 // if it is unknown if dst_type derives from static_type.
864 if (info->is_dst_type_derived_from_static_type != no)
865 {
866 // Set up flags to record results from all base classes
867 bool is_dst_type_derived_from_static_type = false;
868
869 // We've found a dst_type with a potentially public path to here.
870 // We have to assume the path is public because it may become
871 // public later (if we get back to here with a public path).
872 // We can stop looking above if:
873 // 1. We've found a public path to (static_ptr, static_type).
874 // 2. We've found an ambiguous cast from (static_ptr, static_type) to a dst_type.
875 // This is detected at the (static_ptr, static_type).
876 // 3. We can prove that there is no public path to (static_ptr, static_type)
877 // above here.
878 const Iter e = __base_info + __base_count;
879 for (Iter p = __base_info; p < e; ++p)
880 {
881 // Zero out found flags
882 info->found_our_static_ptr = false;
883 info->found_any_static_type = false;
884 p->search_above_dst(info, current_ptr, current_ptr, public_path, use_strcmp);
885 if (info->search_done)
886 break;
887 if (info->found_any_static_type)
888 {
889 is_dst_type_derived_from_static_type = true;
890 if (info->found_our_static_ptr)
891 {
892 does_dst_type_point_to_our_static_type = true;
893 // If we found what we're looking for, stop looking above.
894 if (info->path_dst_ptr_to_static_ptr == public_path)
895 break;
896 // We found a private path to (static_ptr, static_type)
897 // If there is no diamond then there is only one path
898 // to (static_ptr, static_type) and we just found it.
899 if (!(__flags & __diamond_shaped_mask))
900 break;
901 }
902 else
903 {
904 // If we found a static_type that isn't the one we're looking
905 // for, and if there are no repeated types above here,
906 // then stop looking.
907 if (!(__flags & __non_diamond_repeat_mask))
908 break;
909 }
910 }
911 }
912 // If we found no static_type,s then dst_type doesn't derive
913 // from static_type, else it does. Record this result so that
914 // next time we hit a dst_type we will know not to search above
915 // it if it doesn't derive from static_type.
916 if (is_dst_type_derived_from_static_type)
917 info->is_dst_type_derived_from_static_type = yes;
918 else
919 info->is_dst_type_derived_from_static_type = no;
920 }
921 if (!does_dst_type_point_to_our_static_type)
922 {
923 // We found a dst_type that doesn't point to (static_ptr, static_type)
924 // So record the address of this dst_ptr and increment the
925 // count of the number of such dst_types found in the tree.
926 info->dst_ptr_not_leading_to_static_ptr = current_ptr;
927 info->number_to_dst_ptr += 1;
928 // If there exists another dst with a private path to
929 // (static_ptr, static_type), then the cast from
930 // (dynamic_ptr, dynamic_type) to dst_type is now ambiguous,
931 // so stop search.
932 if (info->number_to_static_ptr == 1 &&
933 info->path_dst_ptr_to_static_ptr == not_public_path)
934 info->search_done = true;
935 }
936 }
937 }
938 else
939 {
940 // This is not a static_type and not a dst_type.
941 const Iter e = __base_info + __base_count;
942 Iter p = __base_info;
943 p->search_below_dst(info, current_ptr, path_below, use_strcmp);
944 if (++p < e)
945 {
946 if ((__flags & __diamond_shaped_mask) || info->number_to_static_ptr == 1)
947 {
948 // If there are multiple paths to a base above from here, or if
949 // a dst_type pointing to (static_ptr, static_type) has been found,
950 // then there is no way to break out of this loop early unless
951 // something below detects the search is done.
952 do
953 {
954 if (info->search_done)
955 break;
956 p->search_below_dst(info, current_ptr, path_below, use_strcmp);
957 } while (++p < e);
958 }
959 else if (__flags & __non_diamond_repeat_mask)
960 {
961 // There are not multiple paths to any base class from here and a
962 // dst_type pointing to (static_ptr, static_type) has not yet been
963 // found.
964 do
965 {
966 if (info->search_done)
967 break;
968 // If we just found a dst_type with a public path to (static_ptr, static_type),
969 // then the only reason to continue the search is to make sure
970 // no other dst_type points to (static_ptr, static_type).
971 // If !diamond, then we don't need to search here.
972 if (info->number_to_static_ptr == 1 &&
973 info->path_dst_ptr_to_static_ptr == public_path)
974 break;
975 p->search_below_dst(info, current_ptr, path_below, use_strcmp);
976 } while (++p < e);
977 }
978 else
979 {
980 // There are no repeated types above this node.
981 // There are no nodes with multiple parents above this node.
982 // no dst_type has been found to (static_ptr, static_type)
983 do
984 {
985 if (info->search_done)
986 break;
987 // If we just found a dst_type with a public path to (static_ptr, static_type),
988 // then the only reason to continue the search is to make sure sure
989 // no other dst_type points to (static_ptr, static_type).
990 // If !diamond, then we don't need to search here.
991 // if we just found a dst_type with a private path to (static_ptr, static_type),
992 // then we're only looking for a public path to (static_ptr, static_type)
993 // and to check for other dst_types.
994 // If !diamond & !repeat, then there is not a pointer to (static_ptr, static_type)
995 // and not a dst_type under here.
996 if (info->number_to_static_ptr == 1)
997 break;
998 p->search_below_dst(info, current_ptr, path_below, use_strcmp);
999 } while (++p < e);
1000 }
1001 }
1002 }
1003}
1004
1005// This is the same algorithm as __vmi_class_type_info::search_below_dst but
1006// simplified to the case that there is only a single base class.
1007void
1008__si_class_type_info::search_below_dst(__dynamic_cast_info* info,
1009 const void* current_ptr,
1010 int path_below,
1011 bool use_strcmp) const
1012{
1013 if (is_equal(this, info->static_type, use_strcmp))
1014 process_static_type_below_dst(info, current_ptr, path_below);
1015 else if (is_equal(this, info->dst_type, use_strcmp))
1016 {
1017 // We've been here before if we've recorded current_ptr in one of these
1018 // two places:
1019 if (current_ptr == info->dst_ptr_leading_to_static_ptr ||
1020 current_ptr == info->dst_ptr_not_leading_to_static_ptr)
1021 {
1022 // We've seen this node before, and therefore have already searched
1023 // its base classes above.
1024 // Update path to here that is "most public".
1025 if (path_below == public_path)
1026 info->path_dynamic_ptr_to_dst_ptr = public_path;
1027 }
1028 else // We have haven't been here before
1029 {
1030 // Record the access path that got us here
1031 // If there is more than one dst_type this path doesn't matter.
1032 info->path_dynamic_ptr_to_dst_ptr = path_below;
1033 bool does_dst_type_point_to_our_static_type = false;
1034 // Only search above here if dst_type derives from static_type, or
1035 // if it is unknown if dst_type derives from static_type.
1036 if (info->is_dst_type_derived_from_static_type != no)
1037 {
1038 // Set up flags to record results from all base classes
1039 bool is_dst_type_derived_from_static_type = false;
1040 // Zero out found flags
1041 info->found_our_static_ptr = false;
1042 info->found_any_static_type = false;
1043 __base_type->search_above_dst(info, current_ptr, current_ptr, public_path, use_strcmp);
1044 if (info->found_any_static_type)
1045 {
1046 is_dst_type_derived_from_static_type = true;
1047 if (info->found_our_static_ptr)
1048 does_dst_type_point_to_our_static_type = true;
1049 }
1050 // If we found no static_type,s then dst_type doesn't derive
1051 // from static_type, else it does. Record this result so that
1052 // next time we hit a dst_type we will know not to search above
1053 // it if it doesn't derive from static_type.
1054 if (is_dst_type_derived_from_static_type)
1055 info->is_dst_type_derived_from_static_type = yes;
1056 else
1057 info->is_dst_type_derived_from_static_type = no;
1058 }
1059 if (!does_dst_type_point_to_our_static_type)
1060 {
1061 // We found a dst_type that doesn't point to (static_ptr, static_type)
1062 // So record the address of this dst_ptr and increment the
1063 // count of the number of such dst_types found in the tree.
1064 info->dst_ptr_not_leading_to_static_ptr = current_ptr;
1065 info->number_to_dst_ptr += 1;
1066 // If there exists another dst with a private path to
1067 // (static_ptr, static_type), then the cast from
1068 // (dynamic_ptr, dynamic_type) to dst_type is now ambiguous.
1069 if (info->number_to_static_ptr == 1 &&
1070 info->path_dst_ptr_to_static_ptr == not_public_path)
1071 info->search_done = true;
1072 }
1073 }
1074 }
1075 else
1076 {
1077 // This is not a static_type and not a dst_type
1078 __base_type->search_below_dst(info, current_ptr, path_below, use_strcmp);
1079 }
1080}
1081
1082// This is the same algorithm as __vmi_class_type_info::search_below_dst but
1083// simplified to the case that there is no base class.
1084void
1085__class_type_info::search_below_dst(__dynamic_cast_info* info,
1086 const void* current_ptr,
1087 int path_below,
1088 bool use_strcmp) const
1089{
1090 if (is_equal(this, info->static_type, use_strcmp))
1091 process_static_type_below_dst(info, current_ptr, path_below);
1092 else if (is_equal(this, info->dst_type, use_strcmp))
1093 {
1094 // We've been here before if we've recorded current_ptr in one of these
1095 // two places:
1096 if (current_ptr == info->dst_ptr_leading_to_static_ptr ||
1097 current_ptr == info->dst_ptr_not_leading_to_static_ptr)
1098 {
1099 // We've seen this node before, and therefore have already searched
1100 // its base classes above.
1101 // Update path to here that is "most public".
1102 if (path_below == public_path)
1103 info->path_dynamic_ptr_to_dst_ptr = public_path;
1104 }
1105 else // We have haven't been here before
1106 {
1107 // Record the access path that got us here
1108 // If there is more than one dst_type this path doesn't matter.
1109 info->path_dynamic_ptr_to_dst_ptr = path_below;
1110 // We found a dst_type that doesn't point to (static_ptr, static_type)
1111 // So record the address of this dst_ptr and increment the
1112 // count of the number of such dst_types found in the tree.
1113 info->dst_ptr_not_leading_to_static_ptr = current_ptr;
1114 info->number_to_dst_ptr += 1;
1115 // If there exists another dst with a private path to
1116 // (static_ptr, static_type), then the cast from
1117 // (dynamic_ptr, dynamic_type) to dst_type is now ambiguous.
1118 if (info->number_to_static_ptr == 1 &&
1119 info->path_dst_ptr_to_static_ptr == not_public_path)
1120 info->search_done = true;
1121 // We found that dst_type does not derive from static_type
1122 info->is_dst_type_derived_from_static_type = no;
1123 }
1124 }
1125}
1126
1127// Call this function when searching above a dst_type node. This function searches
1128// for a public path to (static_ptr, static_type).
1129// This function is guaranteed not to find a node of type dst_type.
1130// Theoretically this is a very simple function which just stops if it finds a
1131// static_type node: All the hoopla surrounding the search code is doing
1132// nothing but looking for excuses to stop the search prematurely (break out of
1133// the for-loop). That is, the algorithm below is simply an optimization of this:
1134// void
1135// __vmi_class_type_info::search_above_dst(__dynamic_cast_info* info,
1136// const void* dst_ptr,
1137// const void* current_ptr,
1138// int path_below) const
1139// {
1140// if (this == info->static_type)
1141// process_static_type_above_dst(info, dst_ptr, current_ptr, path_below);
1142// else
1143// {
1144// typedef const __base_class_type_info* Iter;
1145// // This is not a static_type and not a dst_type
1146// for (Iter p = __base_info, e = __base_info + __base_count; p < e; ++p)
1147// {
1148// p->search_above_dst(info, dst_ptr, current_ptr, public_path);
1149// // break out early here if you can detect it doesn't matter if you do
1150// }
1151// }
1152// }
1153void
1154__vmi_class_type_info::search_above_dst(__dynamic_cast_info* info,
1155 const void* dst_ptr,
1156 const void* current_ptr,
1157 int path_below,
1158 bool use_strcmp) const
1159{
1160 if (is_equal(this, info->static_type, use_strcmp))
1161 process_static_type_above_dst(info, dst_ptr, current_ptr, path_below);
1162 else
1163 {
1164 typedef const __base_class_type_info* Iter;
1165 // This is not a static_type and not a dst_type
1166 // Save flags so they can be restored when returning to nodes below.
1167 bool found_our_static_ptr = info->found_our_static_ptr;
1168 bool found_any_static_type = info->found_any_static_type;
1169 // We've found a dst_type below with a path to here. If the path
1170 // to here is not public, there may be another path to here that
1171 // is public. So we have to assume that the path to here is public.
1172 // We can stop looking above if:
1173 // 1. We've found a public path to (static_ptr, static_type).
1174 // 2. We've found an ambiguous cast from (static_ptr, static_type) to a dst_type.
1175 // This is detected at the (static_ptr, static_type).
1176 // 3. We can prove that there is no public path to (static_ptr, static_type)
1177 // above here.
1178 const Iter e = __base_info + __base_count;
1179 Iter p = __base_info;
1180 // Zero out found flags
1181 info->found_our_static_ptr = false;
1182 info->found_any_static_type = false;
1183 p->search_above_dst(info, dst_ptr, current_ptr, path_below, use_strcmp);
1184 found_our_static_ptr |= info->found_our_static_ptr;
1185 found_any_static_type |= info->found_any_static_type;
1186 if (++p < e)
1187 {
1188 do
1189 {
1190 if (info->search_done)
1191 break;
1192 if (info->found_our_static_ptr)
1193 {
1194 // If we found what we're looking for, stop looking above.
1195 if (info->path_dst_ptr_to_static_ptr == public_path)
1196 break;
1197 // We found a private path to (static_ptr, static_type)
1198 // If there is no diamond then there is only one path
1199 // to (static_ptr, static_type) from here and we just found it.
1200 if (!(__flags & __diamond_shaped_mask))
1201 break;
1202 }
1203 else if (info->found_any_static_type)
1204 {
1205 // If we found a static_type that isn't the one we're looking
1206 // for, and if there are no repeated types above here,
1207 // then stop looking.
1208 if (!(__flags & __non_diamond_repeat_mask))
1209 break;
1210 }
1211 // Zero out found flags
1212 info->found_our_static_ptr = false;
1213 info->found_any_static_type = false;
1214 p->search_above_dst(info, dst_ptr, current_ptr, path_below, use_strcmp);
1215 found_our_static_ptr |= info->found_our_static_ptr;
1216 found_any_static_type |= info->found_any_static_type;
1217 } while (++p < e);
1218 }
1219 // Restore flags
1220 info->found_our_static_ptr = found_our_static_ptr;
1221 info->found_any_static_type = found_any_static_type;
1222 }
1223}
1224
1225// This is the same algorithm as __vmi_class_type_info::search_above_dst but
1226// simplified to the case that there is only a single base class.
1227void
1228__si_class_type_info::search_above_dst(__dynamic_cast_info* info,
1229 const void* dst_ptr,
1230 const void* current_ptr,
1231 int path_below,
1232 bool use_strcmp) const
1233{
1234 if (is_equal(this, info->static_type, use_strcmp))
1235 process_static_type_above_dst(info, dst_ptr, current_ptr, path_below);
1236 else
1237 __base_type->search_above_dst(info, dst_ptr, current_ptr, path_below, use_strcmp);
1238}
1239
1240// This is the same algorithm as __vmi_class_type_info::search_above_dst but
1241// simplified to the case that there is no base class.
1242void
1243__class_type_info::search_above_dst(__dynamic_cast_info* info,
1244 const void* dst_ptr,
1245 const void* current_ptr,
1246 int path_below,
1247 bool use_strcmp) const
1248{
1249 if (is_equal(this, info->static_type, use_strcmp))
1250 process_static_type_above_dst(info, dst_ptr, current_ptr, path_below);
1251}
1252
1253// The search functions for __base_class_type_info are simply convenience
1254// functions for adjusting the current_ptr and path_below as the search is
1255// passed up to the base class node.
1256
1257void
1258__base_class_type_info::search_above_dst(__dynamic_cast_info* info,
1259 const void* dst_ptr,
1260 const void* current_ptr,
1261 int path_below,
1262 bool use_strcmp) const
1263{
1264 ptrdiff_t offset_to_base = __offset_flags >> __offset_shift;
1265 if (__offset_flags & __virtual_mask)
1266 {
1267 const char* vtable = *static_cast<const char*const*>(current_ptr);
1268 offset_to_base = *reinterpret_cast<const ptrdiff_t*>(vtable + offset_to_base);
1269 }
1270 __base_type->search_above_dst(info, dst_ptr,
1271 static_cast<const char*>(current_ptr) + offset_to_base,
1272 (__offset_flags & __public_mask) ?
1273 path_below :
1274 not_public_path,
1275 use_strcmp);
1276}
1277
1278void
1279__base_class_type_info::search_below_dst(__dynamic_cast_info* info,
1280 const void* current_ptr,
1281 int path_below,
1282 bool use_strcmp) const
1283{
1284 ptrdiff_t offset_to_base = __offset_flags >> __offset_shift;
1285 if (__offset_flags & __virtual_mask)
1286 {
1287 const char* vtable = *static_cast<const char*const*>(current_ptr);
1288 offset_to_base = *reinterpret_cast<const ptrdiff_t*>(vtable + offset_to_base);
1289 }
1290 __base_type->search_below_dst(info,
1291 static_cast<const char*>(current_ptr) + offset_to_base,
1292 (__offset_flags & __public_mask) ?
1293 path_below :
1294 not_public_path,
1295 use_strcmp);
1296}
1297
1298} // __cxxabiv1
1299