1//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___EXCEPTION_EXCEPTION_H
10#define _LIBCPP___EXCEPTION_EXCEPTION_H
11
12#include <__config>
13
14// <vcruntime_exception.h> defines its own std::exception and std::bad_exception types,
15// which we use in order to be ABI-compatible with other STLs on Windows.
16#if defined(_LIBCPP_ABI_VCRUNTIME)
17# include <vcruntime_exception.h>
18#endif
19
20#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
21# pragma GCC system_header
22#endif
23
24_LIBCPP_BEGIN_UNVERSIONED_NAMESPACE_STD
25_LIBCPP_BEGIN_EXPLICIT_ABI_ANNOTATIONS
26
27#if defined(_LIBCPP_ABI_VCRUNTIME) && (!defined(_HAS_EXCEPTIONS) || _HAS_EXCEPTIONS != 0)
28// The std::exception class was already included above, but we're explicit about this condition here for clarity.
29
30#elif defined(_LIBCPP_ABI_VCRUNTIME) && _HAS_EXCEPTIONS == 0
31// However, <vcruntime_exception.h> does not define std::exception and std::bad_exception
32// when _HAS_EXCEPTIONS == 0.
33//
34// Since libc++ still wants to provide the std::exception hierarchy even when _HAS_EXCEPTIONS == 0
35// (after all those are simply types like any other), we define an ABI-compatible version
36// of the VCRuntime std::exception and std::bad_exception types in that mode.
37
38struct __std_exception_data {
39 char const* _What;
40 bool _DoFree;
41};
42
43class exception { // base of all library exceptions
44public:
45 exception() _NOEXCEPT : __data_() {}
46
47 explicit exception(char const* __message) _NOEXCEPT : __data_() {
48 __data_._What = __message;
49 __data_._DoFree = true;
50 }
51
52 exception(exception const&) _NOEXCEPT : __data_() {}
53
54 exception& operator=(exception const&) _NOEXCEPT { return *this; }
55
56 virtual ~exception() _NOEXCEPT {}
57
58 [[__nodiscard__]] virtual char const* what() const _NOEXCEPT {
59 return __data_._What ? __data_._What : "Unknown exception";
60 }
61
62private:
63 __std_exception_data __data_;
64};
65
66class bad_exception : public exception {
67public:
68 bad_exception() _NOEXCEPT : exception("bad exception") {}
69};
70
71#else // !defined(_LIBCPP_ABI_VCRUNTIME)
72// On all other platforms, we define our own std::exception and std::bad_exception types
73// regardless of whether exceptions are turned on as a language feature.
74
75class _LIBCPP_EXPORTED_FROM_ABI exception {
76public:
77 _LIBCPP_HIDE_FROM_ABI exception() _NOEXCEPT {}
78 _LIBCPP_HIDE_FROM_ABI exception(const exception&) _NOEXCEPT = default;
79 _LIBCPP_HIDE_FROM_ABI exception& operator=(const exception&) _NOEXCEPT = default;
80
81 virtual ~exception() _NOEXCEPT;
82 [[__nodiscard__]] virtual const char* what() const _NOEXCEPT;
83};
84
85class _LIBCPP_EXPORTED_FROM_ABI bad_exception : public exception {
86public:
87 _LIBCPP_HIDE_FROM_ABI bad_exception() _NOEXCEPT {}
88 _LIBCPP_HIDE_FROM_ABI bad_exception(const bad_exception&) _NOEXCEPT = default;
89 _LIBCPP_HIDE_FROM_ABI bad_exception& operator=(const bad_exception&) _NOEXCEPT = default;
90 ~bad_exception() _NOEXCEPT override;
91 [[__nodiscard__]] const char* what() const _NOEXCEPT override;
92};
93#endif // !_LIBCPP_ABI_VCRUNTIME
94
95_LIBCPP_END_EXPLICIT_ABI_ANNOTATIONS
96_LIBCPP_END_UNVERSIONED_NAMESPACE_STD
97
98#endif // _LIBCPP___EXCEPTION_EXCEPTION_H
99