//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "private_typeinfo.h"
// The flag _LIBCXXABI_FORGIVING_DYNAMIC_CAST is used to make dynamic_cast
// more forgiving when type_info's mistakenly have hidden visibility and
// thus multiple type_infos can exist for a single type.
//
// When _LIBCXXABI_FORGIVING_DYNAMIC_CAST is defined, and only in the case where
// there is a detected inconsistency in the type_info hierarchy during a
// dynamic_cast, then the equality operation will fall back to using strcmp
// on type_info names to determine type_info equality.
//
// This change happens *only* under dynamic_cast, and only when
// dynamic_cast is faced with the choice: abort, or possibly give back the
// wrong answer. If when the dynamic_cast is done with this fallback
// algorithm and an inconsistency is still detected, dynamic_cast will call
// abort with an appropriate message.
//
// The current implementation of _LIBCXXABI_FORGIVING_DYNAMIC_CAST requires a
// printf-like function called syslog:
//
// void syslog(int facility_priority, const char* format, ...);
//
// If you want this functionality but your platform doesn't have syslog,
// just implement it in terms of fprintf(stderr, ...).
//
// _LIBCXXABI_FORGIVING_DYNAMIC_CAST is currently off by default.
// On Windows, typeids are different between DLLs and EXEs, so comparing
// type_info* will work for typeids from the same compiled file but fail
// for typeids from a DLL and an executable. Among other things, exceptions
// are not caught by handlers since can_catch() returns false.
//
// Defining _LIBCXXABI_FORGIVING_DYNAMIC_CAST does not help since can_catch() calls
// is_equal() with use_strcmp=false so the string names are not compared.
#include <cstdint>
#include <cassert>
#include <string.h>
#include "abort_message.h"
#ifdef _LIBCXXABI_FORGIVING_DYNAMIC_CAST
#include <sys/syslog.h>
#include <atomic>
#endif
#if __has_feature(ptrauth_calls)
#include <ptrauth.h>
#endif
template <typename T>
static inline T* strip_vtable(T* vtable) {
#if __has_feature(ptrauth_calls)
vtable = ptrauth_strip(vtable, ptrauth_key_cxx_vtable_pointer);
#endif
return vtable;
}
static inline
bool
is_equal(const std::type_info* x, const std::type_info* y, bool use_strcmp)
{
// Use std::type_info's default comparison unless we've explicitly asked
// for strcmp.
if (!use_strcmp)
return *x == *y;
// Still allow pointer equality to short circut.
return x == y || strcmp(x->name(), y->name()) == 0;
}
static inline ptrdiff_t update_offset_to_base(const char* vtable,
ptrdiff_t offset_to_base) {
#if __has_feature(cxx_abi_relative_vtable)
// VTable components are 32 bits in the relative vtables ABI.
return *reinterpret_cast<const int32_t*>(vtable + offset_to_base);
#else
return *reinterpret_cast<const ptrdiff_t*>(vtable + offset_to_base);
#endif
}
namespace __cxxabiv1
{
namespace {
struct derived_object_info {
const void* dynamic_ptr;
const __class_type_info* dynamic_type;
std::ptrdiff_t offset_to_derived;
};
/// A helper function that gets (dynamic_ptr, dynamic_type, offset_to_derived) from static_ptr.
void dyn_cast_get_derived_info(derived_object_info* info, const void* static_ptr)
{
#if __has_feature(cxx_abi_relative_vtable)
// The vtable address will point to the first virtual function, which is 8
// bytes after the start of the vtable (4 for the offset from top + 4 for
// the typeinfo component).
const int32_t* vtable =
*reinterpret_cast<const int32_t* const*>(static_ptr);
info->offset_to_derived = static_cast<std::ptrdiff_t>(vtable[-2]);
info->dynamic_ptr = static_cast<const char*>(static_ptr) + info->offset_to_derived;
// The typeinfo component is now a relative offset to a proxy.
int32_t offset_to_ti_proxy = vtable[-1];
const uint8_t* ptr_to_ti_proxy =
reinterpret_cast<const uint8_t*>(vtable) + offset_to_ti_proxy;
info->dynamic_type = *(reinterpret_cast<const __class_type_info* const*>(ptr_to_ti_proxy));
#else
void** vtable = strip_vtable(*static_cast<void** const*>(static_ptr));
info->offset_to_derived = reinterpret_cast<ptrdiff_t>(vtable[-2]);
info->dynamic_ptr = static_cast<const char*>(static_ptr) + info->offset_to_derived;
info->dynamic_type = static_cast<const __class_type_info*>(vtable[-1]);
#endif
}
/// A helper function for __dynamic_cast that casts a base sub-object pointer
/// to the object's dynamic type.
///
/// This function returns the casting result directly. No further processing
/// required.
///
/// Specifically, this function can only be called if the following pre-
/// condition holds:
/// * The dynamic type of the object pointed to by `static_ptr` is exactly
/// the same as `dst_type`.
const void* dyn_cast_to_derived(const void* static_ptr,
const void* dynamic_ptr,
const __class_type_info* static_type,
const __class_type_info* dst_type,
std::ptrdiff_t offset_to_derived,
std::ptrdiff_t src2dst_offset)
{
// We're downcasting from src_type to the complete object's dynamic type.
// This is a really hot path that can be further optimized with the
// `src2dst_offset` hint.
// In such a case, dynamic_ptr already gives the casting result if the
// casting ever succeeds. All we have to do now is to check static_ptr
// points to a public base sub-object of dynamic_ptr.
if (src2dst_offset >= 0)
{
// The static type is a unique public non-virtual base type of
// dst_type at offset `src2dst_offset` from the origin of dst.
// Note that there might be other non-public static_type bases. The
// hint only guarantees that the public base is non-virtual and
// unique. So we have to check whether static_ptr points to that
// unique public base sub-object.
if (offset_to_derived != -src2dst_offset)
return nullptr;
return dynamic_ptr;
}
if (src2dst_offset == -2)
{
// static_type is not a public base of dst_type.
return nullptr;
}
// If src2dst_offset == -3, then:
// src_type is a multiple public base type but never a virtual
// base type. We can't conclude that static_ptr points to those
// public base sub-objects because there might be other non-
// public static_type bases. The search is inevitable.
// Fallback to the slow path to check that static_type is a public
// base type of dynamic_type.
// Using giant short cut. Add that information to info.
__dynamic_cast_info info = {dst_type, static_ptr, static_type, src2dst_offset, 0, 0, 0, 0, 0, 0, 0, 0,
1, // number_of_dst_type
false, false, false, true, nullptr};
// Do the search
dst_type->search_above_dst(&info, dynamic_ptr, dynamic_ptr, public_path, false);
#ifdef _LIBCXXABI_FORGIVING_DYNAMIC_CAST
// The following if should always be false because we should
// definitely find (static_ptr, static_type), either on a public
// or private path
if (info.path_dst_ptr_to_static_ptr == unknown)
{
// We get here only if there is some kind of visibility problem
// in client code.
static_assert(std::atomic<size_t>::is_always_lock_free, "");
static std::atomic<size_t> error_count(0);
size_t error_count_snapshot = error_count.fetch_add(1, std::memory_order_relaxed);
if ((error_count_snapshot & (error_count_snapshot-1)) == 0)
syslog(LOG_ERR, "dynamic_cast error 1: Both of the following type_info's "
"should have public visibility. At least one of them is hidden. %s"
", %s.\n", static_type->name(), dst_type->name());
// Redo the search comparing type_info's using strcmp
info = {dst_type, static_ptr, static_type, src2dst_offset, 0, 0, 0, 0, 0, 0,
0, 0, 0, false, false, false, true, nullptr};
info.number_of_dst_type = 1;
dst_type->search_above_dst(&info, dynamic_ptr, dynamic_ptr, public_path, true);
}
#endif // _LIBCXXABI_FORGIVING_DYNAMIC_CAST
// Query the search.
if (info.path_dst_ptr_to_static_ptr != public_path)
return nullptr;
return dynamic_ptr;
}
/// A helper function for __dynamic_cast that tries to perform a downcast
/// before giving up and falling back to the slow path.
const void* dyn_cast_try_downcast(const void* static_ptr,
const void* dynamic_ptr,
const __class_type_info* dst_type,
const __class_type_info* dynamic_type,
std::ptrdiff_t src2dst_offset)
{
if (src2dst_offset < 0)
{
// We can only optimize the case if the static type is a unique public
// base of dst_type. Give up.
return nullptr;
}
// Pretend there is a dst_type object that leads to static_ptr. Later we
// will check whether this imagined dst_type object exists. If it exists
// then it will be the casting result.
const void* dst_ptr_to_static = reinterpret_cast<const char*>(static_ptr) - src2dst_offset;
if (reinterpret_cast<std::intptr_t>(dst_ptr_to_static) < reinterpret_cast<std::intptr_t>(dynamic_ptr))
{
// The imagined dst_type object does not exist. Bail-out quickly.
return nullptr;
}
// Try to search a path from dynamic_type to dst_type.
__dynamic_cast_info dynamic_to_dst_info = {dynamic_type,
dst_ptr_to_static,
dst_type,
src2dst_offset,
0,
0,
0,
0,
0,
0,
0,
0,
1, // number_of_dst_type
false,
false,
false,
true,
nullptr};
dynamic_type->search_above_dst(&dynamic_to_dst_info, dynamic_ptr, dynamic_ptr, public_path, false);
if (dynamic_to_dst_info.path_dst_ptr_to_static_ptr != unknown) {
// We have found at least one path from dynamic_ptr to dst_ptr. The
// downcast can succeed.
return dst_ptr_to_static;
}
return nullptr;
}
const void* dyn_cast_slow(const void* static_ptr,
const void* dynamic_ptr,
const __class_type_info* static_type,
const __class_type_info* dst_type,
const __class_type_info* dynamic_type,
std::ptrdiff_t src2dst_offset)
{
// Not using giant short cut. Do the search
// Initialize info struct for this search.
__dynamic_cast_info info = {dst_type, static_ptr, static_type, src2dst_offset, 0, 0, 0, 0, 0, 0,
0, 0, 0, false, false, false, true, nullptr};
dynamic_type->search_below_dst(&info, dynamic_ptr, public_path, false);
#ifdef _LIBCXXABI_FORGIVING_DYNAMIC_CAST
// The following if should always be false because we should
// definitely find (static_ptr, static_type), either on a public
// or private path
if (info.path_dst_ptr_to_static_ptr == unknown &&
info.path_dynamic_ptr_to_static_ptr == unknown)
{
static_assert(std::atomic<size_t>::is_always_lock_free, "");
static std::atomic<size_t> error_count(0);
size_t error_count_snapshot = error_count.fetch_add(1, std::memory_order_relaxed);
if ((error_count_snapshot & (error_count_snapshot-1)) == 0)
syslog(LOG_ERR, "dynamic_cast error 2: One or more of the following type_info's "
"has hidden visibility or is defined in more than one translation "
"unit. They should all have public visibility. "
"%s, %s, %s.\n", static_type->name(), dynamic_type->name(),
dst_type->name());
// Redo the search comparing type_info's using strcmp
info = {dst_type, static_ptr, static_type, src2dst_offset, 0, 0, 0, 0, 0, 0,
0, 0, 0, false, false, false, true, nullptr};
dynamic_type->search_below_dst(&info, dynamic_ptr, public_path, true);
}
#endif // _LIBCXXABI_FORGIVING_DYNAMIC_CAST
// Query the search.
switch (info.number_to_static_ptr)
{
case 0:
if (info.number_to_dst_ptr == 1 &&
info.path_dynamic_ptr_to_static_ptr == public_path &&
info.path_dynamic_ptr_to_dst_ptr == public_path)
return info.dst_ptr_not_leading_to_static_ptr;
break;
case 1:
if (info.path_dst_ptr_to_static_ptr == public_path ||
(
info.number_to_dst_ptr == 0 &&
info.path_dynamic_ptr_to_static_ptr == public_path &&
info.path_dynamic_ptr_to_dst_ptr == public_path
)
)
return info.dst_ptr_leading_to_static_ptr;
break;
}
return nullptr;
}
} // namespace
// __shim_type_info
__shim_type_info::~__shim_type_info()
{
}
void __shim_type_info::noop1() const {}
void __shim_type_info::noop2() const {}
// __fundamental_type_info
// This miraculously (compiler magic) emits the type_info's for:
// 1. all of the fundamental types
// 2. pointers to all of the fundamental types
// 3. pointers to all of the const fundamental types
__fundamental_type_info::~__fundamental_type_info()
{
}
// __array_type_info
__array_type_info::~__array_type_info()
{
}
// __function_type_info
__function_type_info::~__function_type_info()
{
}
// __enum_type_info
__enum_type_info::~__enum_type_info()
{
}
// __class_type_info
__class_type_info::~__class_type_info()
{
}
// __si_class_type_info
__si_class_type_info::~__si_class_type_info()
{
}
// __vmi_class_type_info
__vmi_class_type_info::~__vmi_class_type_info()
{
}
// __pbase_type_info
__pbase_type_info::~__pbase_type_info()
{
}
// __pointer_type_info
__pointer_type_info::~__pointer_type_info()
{
}
// __pointer_to_member_type_info
__pointer_to_member_type_info::~__pointer_to_member_type_info()
{
}
// can_catch
// A handler is a match for an exception object of type E if
// 1. The handler is of type cv T or cv T& and E and T are the same type
// (ignoring the top-level cv-qualifiers), or
// 2. the handler is of type cv T or cv T& and T is an unambiguous public
// base class of E, or
// 3. the handler is of type cv1 T* cv2 and E is a pointer type that can be
// converted to the type of the handler by either or both of
// A. a standard pointer conversion (4.10) not involving conversions to
// pointers to private or protected or ambiguous classes
// B. a qualification conversion
// 4. the handler is a pointer or pointer to member type and E is
// std::nullptr_t.
// adjustedPtr:
//
// catch (A& a) : adjustedPtr == &a
// catch (A* a) : adjustedPtr == a
// catch (A** a) : adjustedPtr == a
//
// catch (D2& d2) : adjustedPtr == &d2 (d2 is base class of thrown object)
// catch (D2* d2) : adjustedPtr == d2
// catch (D2*& d2) : adjustedPtr == d2
//
// catch (...) : adjustedPtr == & of the exception
//
// If the thrown type is nullptr_t and the caught type is a pointer to
// member type, adjustedPtr points to a statically-allocated null pointer
// representation of that type.
// Handles bullet 1
bool
__fundamental_type_info::can_catch(const __shim_type_info* thrown_type,
void*&) const
{
return is_equal(this, thrown_type, false);
}
bool
__array_type_info::can_catch(const __shim_type_info*, void*&) const
{
// We can get here if someone tries to catch an array by reference.
// However if someone tries to throw an array, it immediately gets
// converted to a pointer, which will not convert back to an array
// at the catch clause. So this can never catch anything.
return false;
}
bool
__function_type_info::can_catch(const __shim_type_info*, void*&) const
{
// We can get here if someone tries to catch a function by reference.
// However if someone tries to throw a function, it immediately gets
// converted to a pointer, which will not convert back to a function
// at the catch clause. So this can never catch anything.
return false;
}
// Handles bullet 1
bool
__enum_type_info::can_catch(const __shim_type_info* thrown_type,
void*&) const
{
return is_equal(this, thrown_type, false);
}
#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wmissing-field-initializers"
#endif
// Handles bullets 1 and 2
bool
__class_type_info::can_catch(const __shim_type_info* thrown_type,
void*& adjustedPtr) const
{
// bullet 1
if (is_equal(this, thrown_type, false))
return true;
const __class_type_info* thrown_class_type =
dynamic_cast<const __class_type_info*>(thrown_type);
if (thrown_class_type == 0)
return false;
// bullet 2
_LIBCXXABI_ASSERT(adjustedPtr, "catching a class without an object?");
__dynamic_cast_info info = {thrown_class_type, 0, this, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, true, nullptr};
info.number_of_dst_type = 1;
thrown_class_type->has_unambiguous_public_base(&info, adjustedPtr, public_path);
if (info.path_dst_ptr_to_static_ptr == public_path)
{
adjustedPtr = const_cast<void*>(info.dst_ptr_leading_to_static_ptr);
return true;
}
return false;
}
#ifdef __clang__
#pragma clang diagnostic pop
#endif
// When we have an object to inspect - we just pass the pointer to the sub-
// object that matched the static_type we just checked. If that is different
// from any previously recorded pointer to that object type, then we have
// an ambiguous case.
// When we have no object to inspect, we need to account for virtual bases
// explicitly.
// info->vbase_cookie is a pointer to the name of the innermost virtual base
// type, or nullptr if there is no virtual base on the path so far.
// adjustedPtr points to the subobject we just found.
// If vbase_cookie != any previously recorded (including the case of nullptr
// representing an already-found static sub-object) then we have an ambiguous
// case. Assuming that the vbase_cookie values agree; if then we have a
// different offset (adjustedPtr) from any previously recorded, this indicates
// an ambiguous case within the virtual base.
void
__class_type_info::process_found_base_class(__dynamic_cast_info* info,
void* adjustedPtr,
int path_below) const
{
if (info->number_to_static_ptr == 0) {
// First time we found this base
info->dst_ptr_leading_to_static_ptr = adjustedPtr;
info->path_dst_ptr_to_static_ptr = path_below;
// stash the virtual base cookie.
info->dst_ptr_not_leading_to_static_ptr = info->vbase_cookie;
info->number_to_static_ptr = 1;
} else if (info->dst_ptr_not_leading_to_static_ptr == info->vbase_cookie &&
info->dst_ptr_leading_to_static_ptr == adjustedPtr) {
// We've been here before. Update path to "most public"
if (info->path_dst_ptr_to_static_ptr == not_public_path)
info->path_dst_ptr_to_static_ptr = path_below;
} else {
// We've detected an ambiguous cast from (thrown_class_type, adjustedPtr)
// to a static_type.
info->number_to_static_ptr += 1;
info->path_dst_ptr_to_static_ptr = not_public_path;
info->search_done = true;
}
}
void
__class_type_info::has_unambiguous_public_base(__dynamic_cast_info* info,
void* adjustedPtr,
int path_below) const
{
if (is_equal(this, info->static_type, false))
process_found_base_class(info, adjustedPtr, path_below);
}
void
__si_class_type_info::has_unambiguous_public_base(__dynamic_cast_info* info,
void* adjustedPtr,
int path_below) const
{
if (is_equal(this, info->static_type, false))
process_found_base_class(info, adjustedPtr, path_below);
else
__base_type->has_unambiguous_public_base(info, adjustedPtr, path_below);
}
void
__base_class_type_info::has_unambiguous_public_base(__dynamic_cast_info* info,
void* adjustedPtr,
int path_below) const
{
bool is_virtual = __offset_flags & __virtual_mask;
ptrdiff_t offset_to_base = 0;
if (info->have_object) {
/* We have an object to inspect, we can look through its vtables to
find the layout. */
offset_to_base = __offset_flags >> __offset_shift;
if (is_virtual) {
const char* vtable = strip_vtable(*static_cast<const char* const*>(adjustedPtr));
offset_to_base = update_offset_to_base(vtable, offset_to_base);
}
} else if (!is_virtual) {
/* We have no object; however, for non-virtual bases, (since we do not
need to inspect any content) we can pretend to have an object based
at '0'. */
offset_to_base = __offset_flags >> __offset_shift;
} else {
/* No object to inspect, and the next base is virtual.
We cannot indirect through the vtable to find the actual object offset.
So, update vbase_cookie to the new innermost virtual base using the
pointer to the typeinfo name as a key. */
info->vbase_cookie = static_cast<const void*>(__base_type->name());
// .. and reset the pointer.
adjustedPtr = nullptr;
}
__base_type->has_unambiguous_public_base(
info,
static_cast<char*>(adjustedPtr) + offset_to_base,
(__offset_flags & __public_mask) ? path_below : not_public_path);
}
void
__vmi_class_type_info::has_unambiguous_public_base(__dynamic_cast_info* info,
void* adjustedPtr,
int path_below) const
{
if (is_equal(this, info->static_type, false))
process_found_base_class(info, adjustedPtr, path_below);
else
{
typedef const __base_class_type_info* Iter;
const Iter e = __base_info + __base_count;
Iter p = __base_info;
p->has_unambiguous_public_base(info, adjustedPtr, path_below);
if (++p < e)
{
do
{
p->has_unambiguous_public_base(info, adjustedPtr, path_below);
if (info->search_done)
break;
} while (++p < e);
}
}
}
// Handles bullet 1 for both pointers and member pointers
bool
__pbase_type_info::can_catch(const __shim_type_info* thrown_type,
void*&) const
{
bool use_strcmp = this->__flags & (__incomplete_class_mask |
__incomplete_mask);
if (!use_strcmp) {
const __pbase_type_info* thrown_pbase = dynamic_cast<const __pbase_type_info*>(
thrown_type);
if (!thrown_pbase) return false;
use_strcmp = thrown_pbase->__flags & (__incomplete_class_mask |
__incomplete_mask);
}
return is_equal(this, thrown_type, use_strcmp);
}
#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wmissing-field-initializers"
#endif
// Handles bullets 1, 3 and 4
// NOTE: It might not be safe to adjust the pointer if it is not not a pointer
// type. Only adjust the pointer after we know it is safe to do so.
bool
__pointer_type_info::can_catch(const __shim_type_info* thrown_type,
void*& adjustedPtr) const
{
// bullet 4
if (is_equal(thrown_type, &typeid(std::nullptr_t), false)) {
adjustedPtr = nullptr;
return true;
}
// bullet 1
if (__pbase_type_info::can_catch(thrown_type, adjustedPtr)) {
if (adjustedPtr != NULL)
adjustedPtr = *static_cast<void**>(adjustedPtr);
return true;
}
// bullet 3
const __pointer_type_info* thrown_pointer_type =
dynamic_cast<const __pointer_type_info*>(thrown_type);
if (thrown_pointer_type == 0)
return false;
// Do the dereference adjustment
if (adjustedPtr != NULL)
adjustedPtr = *static_cast<void**>(adjustedPtr);
// bullet 3B and 3C
if (thrown_pointer_type->__flags & ~__flags & __no_remove_flags_mask)
return false;
if (__flags & ~thrown_pointer_type->__flags & __no_add_flags_mask)
return false;
if (is_equal(__pointee, thrown_pointer_type->__pointee, false))
return true;
// bullet 3A
if (is_equal(__pointee, &typeid(void), false)) {
// pointers to functions cannot be converted to void*.
// pointers to member functions are not handled here.
const __function_type_info* thrown_function =
dynamic_cast<const __function_type_info*>(thrown_pointer_type->__pointee);
return (thrown_function == nullptr);
}
// Handle pointer to pointer
const __pointer_type_info* nested_pointer_type =
dynamic_cast<const __pointer_type_info*>(__pointee);
if (nested_pointer_type) {
if (~__flags & __const_mask) return false;
return nested_pointer_type->can_catch_nested(thrown_pointer_type->__pointee);
}
// Handle pointer to pointer to member
const __pointer_to_member_type_info* member_ptr_type =
dynamic_cast<const __pointer_to_member_type_info*>(__pointee);
if (member_ptr_type) {
if (~__flags & __const_mask) return false;
return member_ptr_type->can_catch_nested(thrown_pointer_type->__pointee);
}
// Handle pointer to class type
const __class_type_info* catch_class_type =
dynamic_cast<const __class_type_info*>(__pointee);
if (catch_class_type == 0)
return false;
const __class_type_info* thrown_class_type =
dynamic_cast<const __class_type_info*>(thrown_pointer_type->__pointee);
if (thrown_class_type == 0)
return false;
bool have_object = adjustedPtr != nullptr;
__dynamic_cast_info info = {thrown_class_type, 0, catch_class_type, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
have_object, nullptr};
info.number_of_dst_type = 1;
thrown_class_type->has_unambiguous_public_base(&info, adjustedPtr, public_path);
if (info.path_dst_ptr_to_static_ptr == public_path)
{
// In the case of a thrown null pointer, we have no object but we might
// well have computed the offset to where a public sub-object would be.
// However, we do not want to return that offset to the user; we still
// want them to catch a null ptr.
if (have_object)
adjustedPtr = const_cast<void*>(info.dst_ptr_leading_to_static_ptr);
else
adjustedPtr = nullptr;
return true;
}
return false;
}
bool __pointer_type_info::can_catch_nested(
const __shim_type_info* thrown_type) const
{
const __pointer_type_info* thrown_pointer_type =
dynamic_cast<const __pointer_type_info*>(thrown_type);
if (thrown_pointer_type == 0)
return false;
// bullet 3B
if (thrown_pointer_type->__flags & ~__flags)
return false;
if (is_equal(__pointee, thrown_pointer_type->__pointee, false))
return true;
// If the pointed to types differ then the catch type must be const
// qualified.
if (~__flags & __const_mask)
return false;
// Handle pointer to pointer
const __pointer_type_info* nested_pointer_type =
dynamic_cast<const __pointer_type_info*>(__pointee);
if (nested_pointer_type) {
return nested_pointer_type->can_catch_nested(
thrown_pointer_type->__pointee);
}
// Handle pointer to pointer to member
const __pointer_to_member_type_info* member_ptr_type =
dynamic_cast<const __pointer_to_member_type_info*>(__pointee);
if (member_ptr_type) {
return member_ptr_type->can_catch_nested(thrown_pointer_type->__pointee);
}
return false;
}
bool __pointer_to_member_type_info::can_catch(
const __shim_type_info* thrown_type, void*& adjustedPtr) const {
// bullet 4
if (is_equal(thrown_type, &typeid(std::nullptr_t), false)) {
// We assume that the pointer to member representation is the same for
// all pointers to data members and for all pointers to member functions.
struct X {};
if (dynamic_cast<const __function_type_info*>(__pointee)) {
static int (X::*const null_ptr_rep)() = nullptr;
adjustedPtr = const_cast<int (X::**)()>(&null_ptr_rep);
} else {
static int X::*const null_ptr_rep = nullptr;
adjustedPtr = const_cast<int X::**>(&null_ptr_rep);
}
return true;
}
// bullet 1
if (__pbase_type_info::can_catch(thrown_type, adjustedPtr))
return true;
const __pointer_to_member_type_info* thrown_pointer_type =
dynamic_cast<const __pointer_to_member_type_info*>(thrown_type);
if (thrown_pointer_type == 0)
return false;
if (thrown_pointer_type->__flags & ~__flags & __no_remove_flags_mask)
return false;
if (__flags & ~thrown_pointer_type->__flags & __no_add_flags_mask)
return false;
if (!is_equal(__pointee, thrown_pointer_type->__pointee, false))
return false;
if (is_equal(__context, thrown_pointer_type->__context, false))
return true;
// [except.handle] does not allow the pointer-to-member conversions mentioned
// in [mem.conv] to take place. For this reason we don't check Derived->Base
// for Derived->Base conversions.
return false;
}
bool __pointer_to_member_type_info::can_catch_nested(
const __shim_type_info* thrown_type) const
{
const __pointer_to_member_type_info* thrown_member_ptr_type =
dynamic_cast<const __pointer_to_member_type_info*>(thrown_type);
if (thrown_member_ptr_type == 0)
return false;
if (~__flags & thrown_member_ptr_type->__flags)
return false;
if (!is_equal(__pointee, thrown_member_ptr_type->__pointee, false))
return false;
if (!is_equal(__context, thrown_member_ptr_type->__context, false))
return false;
return true;
}
#ifdef __clang__
#pragma clang diagnostic pop
#endif
#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wmissing-field-initializers"
#endif
// __dynamic_cast
// static_ptr: pointer to an object of type static_type; nonnull, and since the
// object is polymorphic, *(void**)static_ptr is a virtual table pointer.
// static_ptr is &v in the expression dynamic_cast<T>(v).
// static_type: static type of the object pointed to by static_ptr.
// dst_type: destination type of the cast (the "T" in "dynamic_cast<T>(v)").
// src2dst_offset: a static hint about the location of the
// source subobject with respect to the complete object;
// special negative values are:
// -1: no hint
// -2: static_type is not a public base of dst_type
// -3: static_type is a multiple public base type but never a
// virtual base type
// otherwise, the static_type type is a unique public nonvirtual
// base type of dst_type at offset src2dst_offset from the
// origin of dst_type.
//
// (dynamic_ptr, dynamic_type) are the run time type of the complete object
// referred to by static_ptr and a pointer to it. These can be found from
// static_ptr for polymorphic types.
// static_type is guaranteed to be a polymorphic type.
//
// (dynamic_ptr, dynamic_type) is the root of a DAG that grows upward. Each
// node of the tree represents a base class/object of its parent (or parents) below.
// Each node is uniquely represented by a pointer to the object, and a pointer
// to a type_info - its type. Different nodes may have the same pointer and
// different nodes may have the same type. But only one node has a specific
// (pointer-value, type) pair. In C++ two objects of the same type can not
// share the same address.
//
// There are two flavors of nodes which have the type dst_type:
// 1. Those that are derived from (below) (static_ptr, static_type).
// 2. Those that are not derived from (below) (static_ptr, static_type).
//
// Invariants of the DAG:
//
// There is at least one path from the root (dynamic_ptr, dynamic_type) to
// the node (static_ptr, static_type). This path may or may not be public.
// There may be more than one such path (some public some not). Such a path may
// or may not go through a node having type dst_type.
//
// No node of type T appears above a node of the same type. That means that
// there is only one node with dynamic_type. And if dynamic_type == dst_type,
// then there is only one dst_type in the DAG.
//
// No node of type dst_type appears above a node of type static_type. Such
// DAG's are possible in C++, but the compiler computes those dynamic_casts at
// compile time, and only calls __dynamic_cast when dst_type lies below
// static_type in the DAG.
//
// dst_type != static_type: The compiler computes the dynamic_cast in this case too.
// dynamic_type != static_type: The compiler computes the dynamic_cast in this case too.
//
// Returns:
//
// If there is exactly one dst_type of flavor 1, and
// If there is a public path from that dst_type to (static_ptr, static_type), or
// If there are 0 dst_types of flavor 2, and there is a public path from
// (dynamic_ptr, dynamic_type) to (static_ptr, static_type) and a public
// path from (dynamic_ptr, dynamic_type) to the one dst_type, then return
// a pointer to that dst_type.
// Else if there are 0 dst_types of flavor 1 and exactly 1 dst_type of flavor 2, and
// if there is a public path from (dynamic_ptr, dynamic_type) to
// (static_ptr, static_type) and a public path from (dynamic_ptr, dynamic_type)
// to the one dst_type, then return a pointer to that one dst_type.
// Else return nullptr.
//
// If dynamic_type == dst_type, then the above algorithm collapses to the
// following cheaper algorithm:
//
// If there is a public path from (dynamic_ptr, dynamic_type) to
// (static_ptr, static_type), then return dynamic_ptr.
// Else return nullptr.
extern "C" _LIBCXXABI_FUNC_VIS void *
__dynamic_cast(const void *static_ptr, const __class_type_info *static_type,
const __class_type_info *dst_type,
std::ptrdiff_t src2dst_offset) {
// Get (dynamic_ptr, dynamic_type) from static_ptr
derived_object_info derived_info;
dyn_cast_get_derived_info(&derived_info, static_ptr);
// Initialize answer to nullptr. This will be changed from the search
// results if a non-null answer is found. Regardless, this is what will
// be returned.
const void* dst_ptr = 0;
// Find out if we can use a giant short cut in the search
if (is_equal(derived_info.dynamic_type, dst_type, false))
{
dst_ptr = dyn_cast_to_derived(static_ptr,
derived_info.dynamic_ptr,
static_type,
dst_type,
derived_info.offset_to_derived,
src2dst_offset);
}
else
{
// Optimize toward downcasting: let's first try to do a downcast before
// falling back to the slow path.
dst_ptr = dyn_cast_try_downcast(static_ptr,
derived_info.dynamic_ptr,
dst_type,
derived_info.dynamic_type,
src2dst_offset);
if (!dst_ptr)
{
dst_ptr = dyn_cast_slow(static_ptr,
derived_info.dynamic_ptr,
static_type,
dst_type,
derived_info.dynamic_type,
src2dst_offset);
}
}
return const_cast<void*>(dst_ptr);
}
#ifdef __clang__
#pragma clang diagnostic pop
#endif
// Call this function when you hit a static_type which is a base (above) a dst_type.
// Let caller know you hit a static_type. But only start recording details if
// this is (static_ptr, static_type) -- the node we are casting from.
// If this is (static_ptr, static_type)
// Record the path (public or not) from the dst_type to here. There may be
// multiple paths from the same dst_type to here, record the "most public" one.
// Record the dst_ptr as pointing to (static_ptr, static_type).
// If more than one (dst_ptr, dst_type) points to (static_ptr, static_type),
// then mark this dyanmic_cast as ambiguous and stop the search.
void
__class_type_info::process_static_type_above_dst(__dynamic_cast_info* info,
const void* dst_ptr,
const void* current_ptr,
int path_below) const
{
// Record that we found a static_type
info->found_any_static_type = true;
if (current_ptr == info->static_ptr)
{
// Record that we found (static_ptr, static_type)
info->found_our_static_ptr = true;
if (info->dst_ptr_leading_to_static_ptr == 0)
{
// First time here
info->dst_ptr_leading_to_static_ptr = dst_ptr;
info->path_dst_ptr_to_static_ptr = path_below;
info->number_to_static_ptr = 1;
// If there is only one dst_type in the entire tree and the path from
// there to here is public then we are done!
if (info->number_of_dst_type == 1 && info->path_dst_ptr_to_static_ptr == public_path)
info->search_done = true;
}
else if (info->dst_ptr_leading_to_static_ptr == dst_ptr)
{
// We've been here before. Update path to "most public"
if (info->path_dst_ptr_to_static_ptr == not_public_path)
info->path_dst_ptr_to_static_ptr = path_below;
// If there is only one dst_type in the entire tree and the path from
// there to here is public then we are done!
if (info->number_of_dst_type == 1 && info->path_dst_ptr_to_static_ptr == public_path)
info->search_done = true;
}
else
{
// We've detected an ambiguous cast from (static_ptr, static_type)
// to a dst_type
info->number_to_static_ptr += 1;
info->search_done = true;
}
}
}
// Call this function when you hit a static_type which is not a base (above) a dst_type.
// If this is (static_ptr, static_type)
// Record the path (public or not) from (dynamic_ptr, dynamic_type) to here. There may be
// multiple paths from (dynamic_ptr, dynamic_type) to here, record the "most public" one.
void
__class_type_info::process_static_type_below_dst(__dynamic_cast_info* info,
const void* current_ptr,
int path_below) const
{
if (current_ptr == info->static_ptr)
{
// Record the most public path from (dynamic_ptr, dynamic_type) to
// (static_ptr, static_type)
if (info->path_dynamic_ptr_to_static_ptr != public_path)
info->path_dynamic_ptr_to_static_ptr = path_below;
}
}
// Call this function when searching below a dst_type node. This function searches
// for a path to (static_ptr, static_type) and for paths to one or more dst_type nodes.
// If it finds a static_type node, there is no need to further search base classes
// above.
// If it finds a dst_type node it should search base classes using search_above_dst
// to find out if this dst_type points to (static_ptr, static_type) or not.
// Either way, the dst_type is recorded as one of two "flavors": one that does
// or does not point to (static_ptr, static_type).
// If this is neither a static_type nor a dst_type node, continue searching
// base classes above.
// All the hoopla surrounding the search code is doing nothing but looking for
// excuses to stop the search prematurely (break out of the for-loop). That is,
// the algorithm below is simply an optimization of this:
// void
// __vmi_class_type_info::search_below_dst(__dynamic_cast_info* info,
// const void* current_ptr,
// int path_below) const
// {
// typedef const __base_class_type_info* Iter;
// if (this == info->static_type)
// process_static_type_below_dst(info, current_ptr, path_below);
// else if (this == info->dst_type)
// {
// // Record the most public access path that got us here
// if (info->path_dynamic_ptr_to_dst_ptr != public_path)
// info->path_dynamic_ptr_to_dst_ptr = path_below;
// bool does_dst_type_point_to_our_static_type = false;
// for (Iter p = __base_info, e= __base_info + __base_count; p < e; ++p)
// {
// p->search_above_dst(info, current_ptr, current_ptr, public_path);
// if (info->found_our_static_ptr)
// does_dst_type_point_to_our_static_type = true;
// // break out early here if you can detect it doesn't matter if you do
// }
// if (!does_dst_type_point_to_our_static_type)
// {
// // We found a dst_type that doesn't point to (static_ptr, static_type)
// // So record the address of this dst_ptr and increment the
// // count of the number of such dst_types found in the tree.
// info->dst_ptr_not_leading_to_static_ptr = current_ptr;
// info->number_to_dst_ptr += 1;
// }
// }
// else
// {
// // This is not a static_type and not a dst_type.
// for (Iter p = __base_info, e = __base_info + __base_count; p < e; ++p)
// {
// p->search_below_dst(info, current_ptr, public_path);
// // break out early here if you can detect it doesn't matter if you do
// }
// }
// }
void
__vmi_class_type_info::search_below_dst(__dynamic_cast_info* info,
const void* current_ptr,
int path_below,
bool use_strcmp) const
{
typedef const __base_class_type_info* Iter;
if (is_equal(this, info->static_type, use_strcmp))
process_static_type_below_dst(info, current_ptr, path_below);
else if (is_equal(this, info->dst_type, use_strcmp))
{
// We've been here before if we've recorded current_ptr in one of these
// two places:
if (current_ptr == info->dst_ptr_leading_to_static_ptr ||
current_ptr == info->dst_ptr_not_leading_to_static_ptr)
{
// We've seen this node before, and therefore have already searched
// its base classes above.
// Update path to here that is "most public".
if (path_below == public_path)
info->path_dynamic_ptr_to_dst_ptr = public_path;
}
else // We have haven't been here before
{
// Record the access path that got us here
// If there is more than one dst_type this path doesn't matter.
info->path_dynamic_ptr_to_dst_ptr = path_below;
bool does_dst_type_point_to_our_static_type = false;
// Only search above here if dst_type derives from static_type, or
// if it is unknown if dst_type derives from static_type.
if (info->is_dst_type_derived_from_static_type != no)
{
// Set up flags to record results from all base classes
bool is_dst_type_derived_from_static_type = false;
// We've found a dst_type with a potentially public path to here.
// We have to assume the path is public because it may become
// public later (if we get back to here with a public path).
// We can stop looking above if:
// 1. We've found a public path to (static_ptr, static_type).
// 2. We've found an ambiguous cast from (static_ptr, static_type) to a dst_type.
// This is detected at the (static_ptr, static_type).
// 3. We can prove that there is no public path to (static_ptr, static_type)
// above here.
const Iter e = __base_info + __base_count;
for (Iter p = __base_info; p < e; ++p)
{
// Zero out found flags
info->found_our_static_ptr = false;
info->found_any_static_type = false;
p->search_above_dst(info, current_ptr, current_ptr, public_path, use_strcmp);
if (info->search_done)
break;
if (info->found_any_static_type)
{
is_dst_type_derived_from_static_type = true;
if (info->found_our_static_ptr)
{
does_dst_type_point_to_our_static_type = true;
// If we found what we're looking for, stop looking above.
if (info->path_dst_ptr_to_static_ptr == public_path)
break;
// We found a private path to (static_ptr, static_type)
// If there is no diamond then there is only one path
// to (static_ptr, static_type) and we just found it.
if (!(__flags & __diamond_shaped_mask))
break;
}
else
{
// If we found a static_type that isn't the one we're looking
// for, and if there are no repeated types above here,
// then stop looking.
if (!(__flags & __non_diamond_repeat_mask))
break;
}
}
}
// If we found no static_type,s then dst_type doesn't derive
// from static_type, else it does. Record this result so that
// next time we hit a dst_type we will know not to search above
// it if it doesn't derive from static_type.
if (is_dst_type_derived_from_static_type)
info->is_dst_type_derived_from_static_type = yes;
else
info->is_dst_type_derived_from_static_type = no;
}
if (!does_dst_type_point_to_our_static_type)
{
// We found a dst_type that doesn't point to (static_ptr, static_type)
// So record the address of this dst_ptr and increment the
// count of the number of such dst_types found in the tree.
info->dst_ptr_not_leading_to_static_ptr = current_ptr;
info->number_to_dst_ptr += 1;
// If there exists another dst with a private path to
// (static_ptr, static_type), then the cast from
// (dynamic_ptr, dynamic_type) to dst_type is now ambiguous,
// so stop search.
if (info->number_to_static_ptr == 1 &&
info->path_dst_ptr_to_static_ptr == not_public_path)
info->search_done = true;
}
}
}
else
{
// This is not a static_type and not a dst_type.
const Iter e = __base_info + __base_count;
Iter p = __base_info;
p->search_below_dst(info, current_ptr, path_below, use_strcmp);
if (++p < e)
{
if ((__flags & __diamond_shaped_mask) || info->number_to_static_ptr == 1)
{
// If there are multiple paths to a base above from here, or if
// a dst_type pointing to (static_ptr, static_type) has been found,
// then there is no way to break out of this loop early unless
// something below detects the search is done.
do
{
if (info->search_done)
break;
p->search_below_dst(info, current_ptr, path_below, use_strcmp);
} while (++p < e);
}
else if (__flags & __non_diamond_repeat_mask)
{
// There are not multiple paths to any base class from here and a
// dst_type pointing to (static_ptr, static_type) has not yet been
// found.
do
{
if (info->search_done)
break;
// If we just found a dst_type with a public path to (static_ptr, static_type),
// then the only reason to continue the search is to make sure
// no other dst_type points to (static_ptr, static_type).
// If !diamond, then we don't need to search here.
if (info->number_to_static_ptr == 1 &&
info->path_dst_ptr_to_static_ptr == public_path)
break;
p->search_below_dst(info, current_ptr, path_below, use_strcmp);
} while (++p < e);
}
else
{
// There are no repeated types above this node.
// There are no nodes with multiple parents above this node.
// no dst_type has been found to (static_ptr, static_type)
do
{
if (info->search_done)
break;
// If we just found a dst_type with a public path to (static_ptr, static_type),
// then the only reason to continue the search is to make sure
// no other dst_type points to (static_ptr, static_type).
// If !diamond, then we don't need to search here.
// if we just found a dst_type with a private path to (static_ptr, static_type),
// then we're only looking for a public path to (static_ptr, static_type)
// and to check for other dst_types.
// If !diamond & !repeat, then there is not a pointer to (static_ptr, static_type)
// and not a dst_type under here.
if (info->number_to_static_ptr == 1)
break;
p->search_below_dst(info, current_ptr, path_below, use_strcmp);
} while (++p < e);
}
}
}
}
// This is the same algorithm as __vmi_class_type_info::search_below_dst but
// simplified to the case that there is only a single base class.
void
__si_class_type_info::search_below_dst(__dynamic_cast_info* info,
const void* current_ptr,
int path_below,
bool use_strcmp) const
{
if (is_equal(this, info->static_type, use_strcmp))
process_static_type_below_dst(info, current_ptr, path_below);
else if (is_equal(this, info->dst_type, use_strcmp))
{
// We've been here before if we've recorded current_ptr in one of these
// two places:
if (current_ptr == info->dst_ptr_leading_to_static_ptr ||
current_ptr == info->dst_ptr_not_leading_to_static_ptr)
{
// We've seen this node before, and therefore have already searched
// its base classes above.
// Update path to here that is "most public".
if (path_below == public_path)
info->path_dynamic_ptr_to_dst_ptr = public_path;
}
else // We have haven't been here before
{
// Record the access path that got us here
// If there is more than one dst_type this path doesn't matter.
info->path_dynamic_ptr_to_dst_ptr = path_below;
bool does_dst_type_point_to_our_static_type = false;
// Only search above here if dst_type derives from static_type, or
// if it is unknown if dst_type derives from static_type.
if (info->is_dst_type_derived_from_static_type != no)
{
// Set up flags to record results from all base classes
bool is_dst_type_derived_from_static_type = false;
// Zero out found flags
info->found_our_static_ptr = false;
info->found_any_static_type = false;
__base_type->search_above_dst(info, current_ptr, current_ptr, public_path, use_strcmp);
if (info->found_any_static_type)
{
is_dst_type_derived_from_static_type = true;
if (info->found_our_static_ptr)
does_dst_type_point_to_our_static_type = true;
}
// If we found no static_type,s then dst_type doesn't derive
// from static_type, else it does. Record this result so that
// next time we hit a dst_type we will know not to search above
// it if it doesn't derive from static_type.
if (is_dst_type_derived_from_static_type)
info->is_dst_type_derived_from_static_type = yes;
else
info->is_dst_type_derived_from_static_type = no;
}
if (!does_dst_type_point_to_our_static_type)
{
// We found a dst_type that doesn't point to (static_ptr, static_type)
// So record the address of this dst_ptr and increment the
// count of the number of such dst_types found in the tree.
info->dst_ptr_not_leading_to_static_ptr = current_ptr;
info->number_to_dst_ptr += 1;
// If there exists another dst with a private path to
// (static_ptr, static_type), then the cast from
// (dynamic_ptr, dynamic_type) to dst_type is now ambiguous.
if (info->number_to_static_ptr == 1 &&
info->path_dst_ptr_to_static_ptr == not_public_path)
info->search_done = true;
}
}
}
else
{
// This is not a static_type and not a dst_type
__base_type->search_below_dst(info, current_ptr, path_below, use_strcmp);
}
}
// This is the same algorithm as __vmi_class_type_info::search_below_dst but
// simplified to the case that there is no base class.
void
__class_type_info::search_below_dst(__dynamic_cast_info* info,
const void* current_ptr,
int path_below,
bool use_strcmp) const
{
if (is_equal(this, info->static_type, use_strcmp))
process_static_type_below_dst(info, current_ptr, path_below);
else if (is_equal(this, info->dst_type, use_strcmp))
{
// We've been here before if we've recorded current_ptr in one of these
// two places:
if (current_ptr == info->dst_ptr_leading_to_static_ptr ||
current_ptr == info->dst_ptr_not_leading_to_static_ptr)
{
// We've seen this node before, and therefore have already searched
// its base classes above.
// Update path to here that is "most public".
if (path_below == public_path)
info->path_dynamic_ptr_to_dst_ptr = public_path;
}
else // We have haven't been here before
{
// Record the access path that got us here
// If there is more than one dst_type this path doesn't matter.
info->path_dynamic_ptr_to_dst_ptr = path_below;
// We found a dst_type that doesn't point to (static_ptr, static_type)
// So record the address of this dst_ptr and increment the
// count of the number of such dst_types found in the tree.
info->dst_ptr_not_leading_to_static_ptr = current_ptr;
info->number_to_dst_ptr += 1;
// If there exists another dst with a private path to
// (static_ptr, static_type), then the cast from
// (dynamic_ptr, dynamic_type) to dst_type is now ambiguous.
if (info->number_to_static_ptr == 1 &&
info->path_dst_ptr_to_static_ptr == not_public_path)
info->search_done = true;
// We found that dst_type does not derive from static_type
info->is_dst_type_derived_from_static_type = no;
}
}
}
// Call this function when searching above a dst_type node. This function searches
// for a public path to (static_ptr, static_type).
// This function is guaranteed not to find a node of type dst_type.
// Theoretically this is a very simple function which just stops if it finds a
// static_type node: All the hoopla surrounding the search code is doing
// nothing but looking for excuses to stop the search prematurely (break out of
// the for-loop). That is, the algorithm below is simply an optimization of this:
// void
// __vmi_class_type_info::search_above_dst(__dynamic_cast_info* info,
// const void* dst_ptr,
// const void* current_ptr,
// int path_below) const
// {
// if (this == info->static_type)
// process_static_type_above_dst(info, dst_ptr, current_ptr, path_below);
// else
// {
// typedef const __base_class_type_info* Iter;
// // This is not a static_type and not a dst_type
// for (Iter p = __base_info, e = __base_info + __base_count; p < e; ++p)
// {
// p->search_above_dst(info, dst_ptr, current_ptr, public_path);
// // break out early here if you can detect it doesn't matter if you do
// }
// }
// }
void
__vmi_class_type_info::search_above_dst(__dynamic_cast_info* info,
const void* dst_ptr,
const void* current_ptr,
int path_below,
bool use_strcmp) const
{
if (is_equal(this, info->static_type, use_strcmp))
process_static_type_above_dst(info, dst_ptr, current_ptr, path_below);
else
{
typedef const __base_class_type_info* Iter;
// This is not a static_type and not a dst_type
// Save flags so they can be restored when returning to nodes below.
bool found_our_static_ptr = info->found_our_static_ptr;
bool found_any_static_type = info->found_any_static_type;
// We've found a dst_type below with a path to here. If the path
// to here is not public, there may be another path to here that
// is public. So we have to assume that the path to here is public.
// We can stop looking above if:
// 1. We've found a public path to (static_ptr, static_type).
// 2. We've found an ambiguous cast from (static_ptr, static_type) to a dst_type.
// This is detected at the (static_ptr, static_type).
// 3. We can prove that there is no public path to (static_ptr, static_type)
// above here.
const Iter e = __base_info + __base_count;
Iter p = __base_info;
// Zero out found flags
info->found_our_static_ptr = false;
info->found_any_static_type = false;
p->search_above_dst(info, dst_ptr, current_ptr, path_below, use_strcmp);
found_our_static_ptr |= info->found_our_static_ptr;
found_any_static_type |= info->found_any_static_type;
if (++p < e)
{
do
{
if (info->search_done)
break;
if (info->found_our_static_ptr)
{
// If we found what we're looking for, stop looking above.
if (info->path_dst_ptr_to_static_ptr == public_path)
break;
// We found a private path to (static_ptr, static_type)
// If there is no diamond then there is only one path
// to (static_ptr, static_type) from here and we just found it.
if (!(__flags & __diamond_shaped_mask))
break;
}
else if (info->found_any_static_type)
{
// If we found a static_type that isn't the one we're looking
// for, and if there are no repeated types above here,
// then stop looking.
if (!(__flags & __non_diamond_repeat_mask))
break;
}
// Zero out found flags
info->found_our_static_ptr = false;
info->found_any_static_type = false;
p->search_above_dst(info, dst_ptr, current_ptr, path_below, use_strcmp);
found_our_static_ptr |= info->found_our_static_ptr;
found_any_static_type |= info->found_any_static_type;
} while (++p < e);
}
// Restore flags
info->found_our_static_ptr = found_our_static_ptr;
info->found_any_static_type = found_any_static_type;
}
}
// This is the same algorithm as __vmi_class_type_info::search_above_dst but
// simplified to the case that there is only a single base class.
void
__si_class_type_info::search_above_dst(__dynamic_cast_info* info,
const void* dst_ptr,
const void* current_ptr,
int path_below,
bool use_strcmp) const
{
if (is_equal(this, info->static_type, use_strcmp))
process_static_type_above_dst(info, dst_ptr, current_ptr, path_below);
else
__base_type->search_above_dst(info, dst_ptr, current_ptr, path_below, use_strcmp);
}
// This is the same algorithm as __vmi_class_type_info::search_above_dst but
// simplified to the case that there is no base class.
void
__class_type_info::search_above_dst(__dynamic_cast_info* info,
const void* dst_ptr,
const void* current_ptr,
int path_below,
bool use_strcmp) const
{
if (is_equal(this, info->static_type, use_strcmp))
process_static_type_above_dst(info, dst_ptr, current_ptr, path_below);
}
// The search functions for __base_class_type_info are simply convenience
// functions for adjusting the current_ptr and path_below as the search is
// passed up to the base class node.
void
__base_class_type_info::search_above_dst(__dynamic_cast_info* info,
const void* dst_ptr,
const void* current_ptr,
int path_below,
bool use_strcmp) const
{
ptrdiff_t offset_to_base = __offset_flags >> __offset_shift;
if (__offset_flags & __virtual_mask)
{
const char* vtable = strip_vtable(*static_cast<const char* const*>(current_ptr));
offset_to_base = update_offset_to_base(vtable, offset_to_base);
}
__base_type->search_above_dst(info, dst_ptr,
static_cast<const char*>(current_ptr) + offset_to_base,
(__offset_flags & __public_mask) ?
path_below :
not_public_path,
use_strcmp);
}
void
__base_class_type_info::search_below_dst(__dynamic_cast_info* info,
const void* current_ptr,
int path_below,
bool use_strcmp) const
{
ptrdiff_t offset_to_base = __offset_flags >> __offset_shift;
if (__offset_flags & __virtual_mask)
{
const char* vtable = strip_vtable(*static_cast<const char* const*>(current_ptr));
offset_to_base = update_offset_to_base(vtable, offset_to_base);
}
__base_type->search_below_dst(info,
static_cast<const char*>(current_ptr) + offset_to_base,
(__offset_flags & __public_mask) ?
path_below :
not_public_path,
use_strcmp);
}
} // __cxxabiv1
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