// -*- C++ -*- Exception handling and frame unwind runtime interface routines. // Copyright (C) 2001-2021 Free Software Foundation, Inc. // // This file is part of GCC. // // GCC is free software; you can redistribute it and/or modify // it under the terms of the GNU General Public License as published by // the Free Software Foundation; either version 3, or (at your option) // any later version. // // GCC is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // // Under Section 7 of GPL version 3, you are granted additional // permissions described in the GCC Runtime Library Exception, version // 3.1, as published by the Free Software Foundation. // You should have received a copy of the GNU General Public License and // a copy of the GCC Runtime Library Exception along with this program; // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see // . // This is derived from the C++ ABI for IA-64. Where we diverge // for cross-architecture compatibility are noted with "@@@". #ifndef _UNWIND_CXX_H #define _UNWIND_CXX_H 1 // Level 2: C++ ABI #include #include #include #include "unwind.h" #include #include #ifdef _GLIBCXX_HAVE_SYS_SDT_H #include /* We only want to use stap probes starting with v3. Earlier versions added too much startup cost. */ #if defined (STAP_PROBE2) && _SDT_NOTE_TYPE >= 3 #define PROBE2(name, arg1, arg2) STAP_PROBE2 (libstdcxx, name, arg1, arg2) #endif #endif #ifndef PROBE2 #define PROBE2(name, arg1, arg2) #endif #pragma GCC visibility push(default) namespace __cxxabiv1 { // A primary C++ exception object consists of a header, which is a wrapper // around an unwind object header with additional C++ specific information, // followed by the exception object itself. struct __cxa_exception { // Manage the exception object itself. std::type_info *exceptionType; void (_GLIBCXX_CDTOR_CALLABI *exceptionDestructor)(void *); // The C++ standard has entertaining rules wrt calling set_terminate // and set_unexpected in the middle of the exception cleanup process. std::unexpected_handler unexpectedHandler; std::terminate_handler terminateHandler; // The caught exception stack threads through here. __cxa_exception *nextException; // How many nested handlers have caught this exception. A negated // value is a signal that this object has been rethrown. int handlerCount; #ifdef __ARM_EABI_UNWINDER__ // Stack of exceptions in cleanups. __cxa_exception* nextPropagatingException; // The number of active cleanup handlers for this exception. int propagationCount; #else // Cache parsed handler data from the personality routine Phase 1 // for Phase 2 and __cxa_call_unexpected. int handlerSwitchValue; const unsigned char *actionRecord; const unsigned char *languageSpecificData; _Unwind_Ptr catchTemp; void *adjustedPtr; #endif // The generic exception header. Must be last. _Unwind_Exception unwindHeader; }; struct __cxa_refcounted_exception { // Manage this header. _Atomic_word referenceCount; // __cxa_exception must be last, and no padding can be after it. __cxa_exception exc; }; // A dependent C++ exception object consists of a wrapper around an unwind // object header with additional C++ specific information, containing a pointer // to a primary exception object. struct __cxa_dependent_exception { // The primary exception this thing depends on. void *primaryException; // Unused member to get similar layout to __cxa_exception, otherwise the // alignment requirements of _Unwind_Exception would require padding bytes // before the unwindHeader member. void (_GLIBCXX_CDTOR_CALLABI *__padding)(void *); // The C++ standard has entertaining rules wrt calling set_terminate // and set_unexpected in the middle of the exception cleanup process. std::unexpected_handler unexpectedHandler; std::terminate_handler terminateHandler; // The caught exception stack threads through here. __cxa_exception *nextException; // How many nested handlers have caught this exception. A negated // value is a signal that this object has been rethrown. int handlerCount; #ifdef __ARM_EABI_UNWINDER__ // Stack of exceptions in cleanups. __cxa_exception* nextPropagatingException; // The number of active cleanup handlers for this exception. int propagationCount; #else // Cache parsed handler data from the personality routine Phase 1 // for Phase 2 and __cxa_call_unexpected. int handlerSwitchValue; const unsigned char *actionRecord; const unsigned char *languageSpecificData; _Unwind_Ptr catchTemp; void *adjustedPtr; #endif // The generic exception header. Must be last. _Unwind_Exception unwindHeader; }; // Each thread in a C++ program has access to a __cxa_eh_globals object. struct __cxa_eh_globals { __cxa_exception *caughtExceptions; unsigned int uncaughtExceptions; #ifdef __ARM_EABI_UNWINDER__ __cxa_exception* propagatingExceptions; #endif }; // @@@ These are not directly specified by the IA-64 C++ ABI. // Handles re-checking the exception specification if unexpectedHandler // throws, and if bad_exception needs to be thrown. Called from the // compiler. extern "C" void __cxa_call_unexpected (void *) __attribute__((__noreturn__)); extern "C" void __cxa_call_terminate (_Unwind_Exception*) throw () __attribute__((__noreturn__)); #ifdef __ARM_EABI_UNWINDER__ // Arm EABI specified routines. typedef enum { ctm_failed = 0, ctm_succeeded = 1, ctm_succeeded_with_ptr_to_base = 2 } __cxa_type_match_result; extern "C" __cxa_type_match_result __cxa_type_match(_Unwind_Exception*, const std::type_info*, bool, void**); extern "C" bool __cxa_begin_cleanup (_Unwind_Exception*); extern "C" void __cxa_end_cleanup (void); #endif // Handles cleanup from transactional memory restart. extern "C" void __cxa_tm_cleanup (void *, void *, unsigned int) throw(); // Invokes given handler, dying appropriately if the user handler was // so inconsiderate as to return. extern void __terminate(std::terminate_handler) throw () __attribute__((__noreturn__)); extern void __unexpected(std::unexpected_handler) __attribute__((__noreturn__)); // The current installed user handlers. extern std::terminate_handler __terminate_handler; extern std::unexpected_handler __unexpected_handler; // These are explicitly GNU C++ specific. // Acquire the C++ exception header from the C++ object. static inline __cxa_exception * __get_exception_header_from_obj (void *ptr) { return reinterpret_cast<__cxa_exception *>(ptr) - 1; } // Acquire the C++ exception header from the generic exception header. static inline __cxa_exception * __get_exception_header_from_ue (_Unwind_Exception *exc) { return reinterpret_cast<__cxa_exception *>(exc + 1) - 1; } // Acquire the C++ refcounted exception header from the C++ object. static inline __cxa_refcounted_exception * __get_refcounted_exception_header_from_obj (void *ptr) { return reinterpret_cast<__cxa_refcounted_exception *>(ptr) - 1; } // Acquire the C++ refcounted exception header from the generic exception // header. static inline __cxa_refcounted_exception * __get_refcounted_exception_header_from_ue (_Unwind_Exception *exc) { return reinterpret_cast<__cxa_refcounted_exception *>(exc + 1) - 1; } static inline __cxa_dependent_exception * __get_dependent_exception_from_ue (_Unwind_Exception *exc) { return reinterpret_cast<__cxa_dependent_exception *>(exc + 1) - 1; } #ifdef __ARM_EABI_UNWINDER__ static inline bool __is_gxx_exception_class(_Unwind_Exception_Class c) { // TODO: Take advantage of the fact that c will always be word aligned. return c[0] == 'G' && c[1] == 'N' && c[2] == 'U' && c[3] == 'C' && c[4] == 'C' && c[5] == '+' && c[6] == '+' && (c[7] == '\0' || c[7] == '\x01'); } // Only checks for primary or dependent, but not that it is a C++ exception at // all. static inline bool __is_dependent_exception(_Unwind_Exception_Class c) { return c[7] == '\x01'; } static inline void __GXX_INIT_PRIMARY_EXCEPTION_CLASS(_Unwind_Exception_Class c) { c[0] = 'G'; c[1] = 'N'; c[2] = 'U'; c[3] = 'C'; c[4] = 'C'; c[5] = '+'; c[6] = '+'; c[7] = '\0'; } static inline void __GXX_INIT_DEPENDENT_EXCEPTION_CLASS(_Unwind_Exception_Class c) { c[0] = 'G'; c[1] = 'N'; c[2] = 'U'; c[3] = 'C'; c[4] = 'C'; c[5] = '+'; c[6] = '+'; c[7] = '\x01'; } static inline bool __is_gxx_forced_unwind_class(_Unwind_Exception_Class c) { return c[0] == 'G' && c[1] == 'N' && c[2] == 'U' && c[3] == 'C' && c[4] == 'F' && c[5] == 'O' && c[6] == 'R' && c[7] == '\0'; } static inline void __GXX_INIT_FORCED_UNWIND_CLASS(_Unwind_Exception_Class c) { c[0] = 'G'; c[1] = 'N'; c[2] = 'U'; c[3] = 'C'; c[4] = 'F'; c[5] = 'O'; c[6] = 'R'; c[7] = '\0'; } static inline void* __gxx_caught_object(_Unwind_Exception* eo) { return (void*)eo->barrier_cache.bitpattern[0]; } #else // !__ARM_EABI_UNWINDER__ // This is the primary exception class we report -- "GNUCC++\0". const _Unwind_Exception_Class __gxx_primary_exception_class = ((((((((_Unwind_Exception_Class) 'G' << 8 | (_Unwind_Exception_Class) 'N') << 8 | (_Unwind_Exception_Class) 'U') << 8 | (_Unwind_Exception_Class) 'C') << 8 | (_Unwind_Exception_Class) 'C') << 8 | (_Unwind_Exception_Class) '+') << 8 | (_Unwind_Exception_Class) '+') << 8 | (_Unwind_Exception_Class) '\0'); // This is the dependent (from std::rethrow_exception) exception class we report // "GNUCC++\x01" const _Unwind_Exception_Class __gxx_dependent_exception_class = ((((((((_Unwind_Exception_Class) 'G' << 8 | (_Unwind_Exception_Class) 'N') << 8 | (_Unwind_Exception_Class) 'U') << 8 | (_Unwind_Exception_Class) 'C') << 8 | (_Unwind_Exception_Class) 'C') << 8 | (_Unwind_Exception_Class) '+') << 8 | (_Unwind_Exception_Class) '+') << 8 | (_Unwind_Exception_Class) '\x01'); static inline bool __is_gxx_exception_class(_Unwind_Exception_Class c) { return c == __gxx_primary_exception_class || c == __gxx_dependent_exception_class; } // Only checks for primary or dependent, but not that it is a C++ exception at // all. static inline bool __is_dependent_exception(_Unwind_Exception_Class c) { return (c & 1); } #define __GXX_INIT_PRIMARY_EXCEPTION_CLASS(c) c = __gxx_primary_exception_class #define __GXX_INIT_DEPENDENT_EXCEPTION_CLASS(c) \ c = __gxx_dependent_exception_class // GNU C++ personality routine, Version 0. extern "C" _Unwind_Reason_Code __gxx_personality_v0 (int, _Unwind_Action, _Unwind_Exception_Class, struct _Unwind_Exception *, struct _Unwind_Context *); // GNU C++ sjlj personality routine, Version 0. extern "C" _Unwind_Reason_Code __gxx_personality_sj0 (int, _Unwind_Action, _Unwind_Exception_Class, struct _Unwind_Exception *, struct _Unwind_Context *); static inline void* __gxx_caught_object(_Unwind_Exception* eo) { // Bad as it looks, this actually works for dependent exceptions too. __cxa_exception* header = __get_exception_header_from_ue (eo); return header->adjustedPtr; } #endif // !__ARM_EABI_UNWINDER__ static inline void* __get_object_from_ue(_Unwind_Exception* eo) throw() { return __is_dependent_exception (eo->exception_class) ? __get_dependent_exception_from_ue (eo)->primaryException : eo + 1; } static inline void * __get_object_from_ambiguous_exception(__cxa_exception *p_or_d) throw() { return __get_object_from_ue (&p_or_d->unwindHeader); } } /* namespace __cxxabiv1 */ #pragma GCC visibility pop #endif // _UNWIND_CXX_H