text: // -*- C++ -*- Exception handling and frame unwind runtime interface routines.
  // Copyright (C) 2001-2015 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
  // <http://www.gnu.org/licenses/>.
  
  // 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 <typeinfo>
  #include <exception>
  #include <cstddef>
  #include "unwind.h"
  #include <bits/atomic_word.h>
  #include <cxxabi.h>
  
  #ifdef _GLIBCXX_HAVE_SYS_SDT_H
  //#include <sys/sdt.h>
  /* 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
  