1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10// libsupc++ does not implement the dependent EH ABI and the functionality
11// it uses to implement std::exception_ptr (which it declares as an alias of
12// std::__exception_ptr::exception_ptr) is not directly exported to clients. So
13// we have little choice but to hijack std::__exception_ptr::exception_ptr's
14// (which fortunately has the same layout as our std::exception_ptr) copy
15// constructor, assignment operator and destructor (which are part of its
16// stable ABI), and its rethrow_exception(std::__exception_ptr::exception_ptr)
17// function.
18
19namespace std {
20
21namespace __exception_ptr
22{
23
24struct exception_ptr
25{
26    void* __ptr_;
27
28    exception_ptr(const exception_ptr&) _NOEXCEPT;
29    exception_ptr& operator=(const exception_ptr&) _NOEXCEPT;
30    ~exception_ptr() _NOEXCEPT;
31};
32
33}
34
35_LIBCPP_NORETURN void rethrow_exception(__exception_ptr::exception_ptr);
36
37exception_ptr::~exception_ptr() _NOEXCEPT
38{
39    reinterpret_cast<__exception_ptr::exception_ptr*>(this)->~exception_ptr();
40}
41
42exception_ptr::exception_ptr(const exception_ptr& other) _NOEXCEPT
43    : __ptr_(other.__ptr_)
44{
45    new (reinterpret_cast<void*>(this)) __exception_ptr::exception_ptr(
46        reinterpret_cast<const __exception_ptr::exception_ptr&>(other));
47}
48
49exception_ptr& exception_ptr::operator=(const exception_ptr& other) _NOEXCEPT
50{
51    *reinterpret_cast<__exception_ptr::exception_ptr*>(this) =
52        reinterpret_cast<const __exception_ptr::exception_ptr&>(other);
53    return *this;
54}
55
56nested_exception::nested_exception() _NOEXCEPT
57    : __ptr_(current_exception())
58{
59}
60
61
62_LIBCPP_NORETURN
63void
64nested_exception::rethrow_nested() const
65{
66    if (__ptr_ == nullptr)
67        terminate();
68    rethrow_exception(__ptr_);
69}
70
71_LIBCPP_NORETURN
72void rethrow_exception(exception_ptr p)
73{
74    rethrow_exception(reinterpret_cast<__exception_ptr::exception_ptr&>(p));
75}
76
77} // namespace std
78