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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// This file implements the default terminate_handler, unexpected_handler and
9// new_handler.
10//===----------------------------------------------------------------------===//
11
12#include <cstdlib> // std::abort
13#include <exception>
14#include <new>
15#include "abort_message.h"
16#include "cxxabi.h"
17#include "cxa_handlers.h"
18#include "cxa_exception.h"
19#include "private_typeinfo.h"
20#include "include/atomic_support.h" // from libc++
21
22#if !defined(LIBCXXABI_SILENT_TERMINATE)
23
24static constinit const char* cause = "uncaught";
25
26# ifndef _LIBCXXABI_NO_EXCEPTIONS
27__attribute__((noreturn))
28static void demangling_terminate_handler()
29{
30 using namespace __cxxabiv1;
31 __cxa_eh_globals* globals = __cxa_get_globals_fast();
32
33 // If there is no uncaught exception, just note that we're terminating
34 if (!globals)
35 __abort_message("terminating");
36
37 __cxa_exception* exception_header = globals->caughtExceptions;
38 if (!exception_header)
39 __abort_message("terminating");
40
41 _Unwind_Exception* unwind_exception =
42 reinterpret_cast<_Unwind_Exception*>(exception_header + 1) - 1;
43
44 // If we're terminating due to a foreign exception
45 if (!__isOurExceptionClass(unwind_exception))
46 __abort_message("terminating due to %s foreign exception", cause);
47
48 void* thrown_object =
49 __getExceptionClass(unwind_exception) == kOurDependentExceptionClass ?
50 ((__cxa_dependent_exception*)exception_header)->primaryException :
51 exception_header + 1;
52 const __shim_type_info* thrown_type =
53 static_cast<const __shim_type_info*>(exception_header->exceptionType);
54
55 auto name = [str = thrown_type->name()] {
56# ifndef LIBCXXABI_NON_DEMANGLING_TERMINATE
57 if (const char* result = __cxxabiv1::__cxa_demangle(str, nullptr, nullptr, nullptr))
58 // We're about to abort(), this memory can never be freed; so it's fine
59 // to just return a raw pointer
60 return result;
61# endif
62 return str;
63 }();
64
65 // If the uncaught exception can be caught with std::exception&
66 const __shim_type_info* catch_type =
67 static_cast<const __shim_type_info*>(&typeid(std::exception));
68 if (catch_type->can_catch(thrown_type, thrown_object))
69 {
70 // Include the what() message from the exception
71 const std::exception* e = static_cast<const std::exception*>(thrown_object);
72 __abort_message("terminating due to %s exception of type %s: %s", cause, name, e->what());
73 }
74 else
75 {
76 // Else just note that we're terminating due to an exception
77 __abort_message("terminating due to %s exception of type %s", cause, name);
78 }
79}
80#else // !_LIBCXXABI_NO_EXCEPTIONS
81__attribute__((noreturn))
82static void demangling_terminate_handler()
83{
84 __abort_message("terminating");
85}
86#endif // !_LIBCXXABI_NO_EXCEPTIONS
87
88__attribute__((noreturn))
89static void demangling_unexpected_handler()
90{
91 cause = "unexpected";
92 std::terminate();
93}
94
95static constexpr std::terminate_handler default_terminate_handler = demangling_terminate_handler;
96static constexpr std::terminate_handler default_unexpected_handler = demangling_unexpected_handler;
97#else // !LIBCXXABI_SILENT_TERMINATE
98static constexpr std::terminate_handler default_terminate_handler = std::abort;
99static constexpr std::terminate_handler default_unexpected_handler = std::terminate;
100#endif // !LIBCXXABI_SILENT_TERMINATE
101
102//
103// Global variables that hold the pointers to the current handler
104//
105_LIBCXXABI_DATA_VIS
106constinit std::terminate_handler __cxa_terminate_handler = default_terminate_handler;
107
108_LIBCXXABI_DATA_VIS
109constinit std::unexpected_handler __cxa_unexpected_handler = default_unexpected_handler;
110
111_LIBCXXABI_DATA_VIS
112constinit std::new_handler __cxa_new_handler = nullptr;
113
114namespace std
115{
116
117unexpected_handler
118set_unexpected(unexpected_handler func) noexcept
119{
120 if (func == 0)
121 func = default_unexpected_handler;
122 return __libcpp_atomic_exchange(&__cxa_unexpected_handler, func,
123 _AO_Acq_Rel);
124}
125
126terminate_handler
127set_terminate(terminate_handler func) noexcept
128{
129 if (func == 0)
130 func = default_terminate_handler;
131 return __libcpp_atomic_exchange(&__cxa_terminate_handler, func,
132 _AO_Acq_Rel);
133}
134
135new_handler
136set_new_handler(new_handler handler) noexcept
137{
138 return __libcpp_atomic_exchange(&__cxa_new_handler, handler, _AO_Acq_Rel);
139}
140
141}