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 "Exception Handling APIs"
9// https://itanium-cxx-abi.github.io/cxx-abi/abi-eh.html
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef _CXA_EXCEPTION_H
14#define _CXA_EXCEPTION_H
15
16#include <exception> // for std::unexpected_handler and std::terminate_handler
17#include "cxxabi.h"
18#include "unwind.h"
19
20namespace __cxxabiv1 {
21
22static const uint64_t kOurExceptionClass = 0x434C4E47432B2B00; // CLNGC++\0
23static const uint64_t kOurDependentExceptionClass = 0x434C4E47432B2B01; // CLNGC++\1
24static const uint64_t get_vendor_and_language = 0xFFFFFFFFFFFFFF00; // mask for CLNGC++
25
26_LIBCXXABI_HIDDEN uint64_t __getExceptionClass (const _Unwind_Exception*);
27_LIBCXXABI_HIDDEN void __setExceptionClass ( _Unwind_Exception*, uint64_t);
28_LIBCXXABI_HIDDEN bool __isOurExceptionClass(const _Unwind_Exception*);
29
30struct _LIBCXXABI_HIDDEN __cxa_exception {
31#if defined(__LP64__) || defined(_WIN64) || defined(_LIBCXXABI_ARM_EHABI)
32 // Now _Unwind_Exception is marked with __attribute__((aligned)),
33 // which implies __cxa_exception is also aligned. Insert padding
34 // in the beginning of the struct, rather than before unwindHeader.
35 void *reserve;
36
37 // This is a new field to support C++11 exception_ptr.
38 // For binary compatibility it is at the start of this
39 // struct which is prepended to the object thrown in
40 // __cxa_allocate_exception.
41 size_t referenceCount;
42#endif
43
44 // Manage the exception object itself.
45 std::type_info *exceptionType;
46#ifdef __wasm__
47 // In Wasm, a destructor returns its argument
48 void *(_LIBCXXABI_DTOR_FUNC *exceptionDestructor)(void *);
49#else
50 void (_LIBCXXABI_DTOR_FUNC *exceptionDestructor)(void *);
51#endif
52 std::unexpected_handler unexpectedHandler;
53 std::terminate_handler terminateHandler;
54
55 __cxa_exception *nextException;
56
57 int handlerCount;
58
59#if defined(_LIBCXXABI_ARM_EHABI)
60 __cxa_exception* nextPropagatingException;
61 int propagationCount;
62#else
63 int handlerSwitchValue;
64 const unsigned char *actionRecord;
65 const unsigned char *languageSpecificData;
66 void *catchTemp;
67 void *adjustedPtr;
68#endif
69
70#if !defined(__LP64__) && !defined(_WIN64) && !defined(_LIBCXXABI_ARM_EHABI)
71 // This is a new field to support C++11 exception_ptr.
72 // For binary compatibility it is placed where the compiler
73 // previously added padding to 64-bit align unwindHeader.
74 size_t referenceCount;
75#endif
76 _Unwind_Exception unwindHeader;
77};
78
79// http://sourcery.mentor.com/archives/cxx-abi-dev/msg01924.html
80// The layout of this structure MUST match the layout of __cxa_exception, with
81// primaryException instead of referenceCount.
82struct _LIBCXXABI_HIDDEN __cxa_dependent_exception {
83#if defined(__LP64__) || defined(_WIN64) || defined(_LIBCXXABI_ARM_EHABI)
84 void* reserve; // padding.
85 void* primaryException;
86#endif
87
88 std::type_info *exceptionType;
89 void (_LIBCXXABI_DTOR_FUNC *exceptionDestructor)(void *);
90 std::unexpected_handler unexpectedHandler;
91 std::terminate_handler terminateHandler;
92
93 __cxa_exception *nextException;
94
95 int handlerCount;
96
97#if defined(_LIBCXXABI_ARM_EHABI)
98 __cxa_exception* nextPropagatingException;
99 int propagationCount;
100#else
101 int handlerSwitchValue;
102 const unsigned char *actionRecord;
103 const unsigned char *languageSpecificData;
104 void * catchTemp;
105 void *adjustedPtr;
106#endif
107
108#if !defined(__LP64__) && !defined(_WIN64) && !defined(_LIBCXXABI_ARM_EHABI)
109 void* primaryException;
110#endif
111 _Unwind_Exception unwindHeader;
112};
113
114// Verify the negative offsets of different fields.
115static_assert(sizeof(_Unwind_Exception) +
116 offsetof(__cxa_exception, unwindHeader) ==
117 sizeof(__cxa_exception),
118 "unwindHeader has wrong negative offsets");
119static_assert(sizeof(_Unwind_Exception) +
120 offsetof(__cxa_dependent_exception, unwindHeader) ==
121 sizeof(__cxa_dependent_exception),
122 "unwindHeader has wrong negative offsets");
123
124#if defined(_LIBCXXABI_ARM_EHABI)
125static_assert(offsetof(__cxa_exception, propagationCount) +
126 sizeof(_Unwind_Exception) + sizeof(void*) ==
127 sizeof(__cxa_exception),
128 "propagationCount has wrong negative offset");
129static_assert(offsetof(__cxa_dependent_exception, propagationCount) +
130 sizeof(_Unwind_Exception) + sizeof(void*) ==
131 sizeof(__cxa_dependent_exception),
132 "propagationCount has wrong negative offset");
133#elif defined(__LP64__) || defined(_WIN64)
134static_assert(offsetof(__cxa_exception, adjustedPtr) +
135 sizeof(_Unwind_Exception) + sizeof(void*) ==
136 sizeof(__cxa_exception),
137 "adjustedPtr has wrong negative offset");
138static_assert(offsetof(__cxa_dependent_exception, adjustedPtr) +
139 sizeof(_Unwind_Exception) + sizeof(void*) ==
140 sizeof(__cxa_dependent_exception),
141 "adjustedPtr has wrong negative offset");
142#else
143static_assert(offsetof(__cxa_exception, referenceCount) +
144 sizeof(_Unwind_Exception) + sizeof(void*) ==
145 sizeof(__cxa_exception),
146 "referenceCount has wrong negative offset");
147static_assert(offsetof(__cxa_dependent_exception, primaryException) +
148 sizeof(_Unwind_Exception) + sizeof(void*) ==
149 sizeof(__cxa_dependent_exception),
150 "primaryException has wrong negative offset");
151#endif
152
153struct _LIBCXXABI_HIDDEN __cxa_eh_globals {
154 __cxa_exception * caughtExceptions;
155 unsigned int uncaughtExceptions;
156#if defined(_LIBCXXABI_ARM_EHABI)
157 __cxa_exception* propagatingExceptions;
158#endif
159};
160
161extern "C" _LIBCXXABI_FUNC_VIS __cxa_eh_globals * __cxa_get_globals ();
162extern "C" _LIBCXXABI_FUNC_VIS __cxa_eh_globals * __cxa_get_globals_fast ();
163
164extern "C" _LIBCXXABI_FUNC_VIS void * __cxa_allocate_dependent_exception ();
165extern "C" _LIBCXXABI_FUNC_VIS void __cxa_free_dependent_exception (void * dependent_exception);
166
167} // namespace __cxxabiv1
168
169#endif // _CXA_EXCEPTION_H
170