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