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// -*- C++ -*- The GNU C++ exception personality routine.

// Copyright (C) 2001, 2002, 2003, 2006 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 2, 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.

//

// You should have received a copy of the GNU General Public License

// along with GCC; see the file COPYING.  If not, write to

// the Free Software Foundation, 51 Franklin Street, Fifth Floor,

// Boston, MA 02110-1301, USA.

// As a special exception, you may use this file as part of a free software

// library without restriction.  Specifically, if other files instantiate

// templates or use macros or inline functions from this file, or you compile

// this file and link it with other files to produce an executable, this

// file does not by itself cause the resulting executable to be covered by

// the GNU General Public License.  This exception does not however

// invalidate any other reasons why the executable file might be covered by

// the GNU General Public License.

#include <bits/c++config.h>

#include <cstdlib>

#include <exception_defines.h>

#include "unwind-cxx.h"

using namespace __cxxabiv1;

#ifdef __ARM_EABI_UNWINDER__

#define NO_SIZE_OF_ENCODED_VALUE

#endif

#include "unwind-pe.h"

struct lsda_header_info

{

  _Unwind_Ptr Start;

  _Unwind_Ptr LPStart;

  _Unwind_Ptr ttype_base;

  const unsigned char *TType;

  const unsigned char *action_table;

  unsigned char ttype_encoding;

  unsigned char call_site_encoding;

};

static const unsigned char *

parse_lsda_header (_Unwind_Context *context, const unsigned char *p,

                   lsda_header_info *info)

{

  _Unwind_Word tmp;

  unsigned char lpstart_encoding;

  info->Start = (context ? _Unwind_GetRegionStart (context) : 0);

  // Find @LPStart, the base to which landing pad offsets are relative.

  lpstart_encoding = *p++;

  if (lpstart_encoding != DW_EH_PE_omit)

    p = read_encoded_value (context, lpstart_encoding, p, &info->LPStart);

  else

    info->LPStart = info->Start;

  // Find @TType, the base of the handler and exception spec type data.

  info->ttype_encoding = *p++;

  if (info->ttype_encoding != DW_EH_PE_omit)

    {

      p = read_uleb128 (p, &tmp);

      info->TType = p + tmp;

    }

  else

    info->TType = 0;

  // The encoding and length of the call-site table; the action table

  // immediately follows.

  info->call_site_encoding = *p++;

  p = read_uleb128 (p, &tmp);

  info->action_table = p + tmp;

  return p;

}

#ifdef __ARM_EABI_UNWINDER__

// Return an element from a type table.

static const std::type_info*

get_ttype_entry(lsda_header_info* info, _Unwind_Word i)

{

  _Unwind_Ptr ptr;

  ptr = (_Unwind_Ptr) (info->TType - (i * 4));

  ptr = _Unwind_decode_target2(ptr);

  return reinterpret_cast<const std::type_info *>(ptr);

}

// The ABI provides a routine for matching exception object types.

typedef _Unwind_Control_Block _throw_typet;

#define get_adjusted_ptr(catch_type, throw_type, thrown_ptr_p) \

  (__cxa_type_match (throw_type, catch_type, false, thrown_ptr_p) \

   != ctm_failed)

// Return true if THROW_TYPE matches one if the filter types.

static bool

check_exception_spec(lsda_header_info* info, _throw_typet* throw_type,

                     void* thrown_ptr, _Unwind_Sword filter_value)

{

  const _Unwind_Word* e = ((const _Unwind_Word*) info->TType)

                          - filter_value - 1;

  while (1)

    {

      const std::type_info* catch_type;

      _Unwind_Word tmp;

      tmp = *e;

      // Zero signals the end of the list.  If we've not found

      // a match by now, then we've failed the specification.

      if (tmp == 0)

        return false;

      tmp = _Unwind_decode_target2((_Unwind_Word) e);

      // Match a ttype entry.

      catch_type = reinterpret_cast<const std::type_info*>(tmp);

      // ??? There is currently no way to ask the RTTI code about the

      // relationship between two types without reference to a specific

      // object.  There should be; then we wouldn't need to mess with

      // thrown_ptr here.

      if (get_adjusted_ptr(catch_type, throw_type, &thrown_ptr))

        return true;

      // Advance to the next entry.

      e++;

    }

}

// Save stage1 handler information in the exception object

static inline void

save_caught_exception(struct _Unwind_Exception* ue_header,

                      struct _Unwind_Context* context,

                      void* thrown_ptr,

                      int handler_switch_value,

                      const unsigned char* language_specific_data,

                      _Unwind_Ptr landing_pad,

                      const unsigned char* action_record

                        __attribute__((__unused__)))

{

    ue_header->barrier_cache.sp = _Unwind_GetGR(context, 13);

    ue_header->barrier_cache.bitpattern[0] = (_uw) thrown_ptr;

    ue_header->barrier_cache.bitpattern[1]

      = (_uw) handler_switch_value;

    ue_header->barrier_cache.bitpattern[2]

      = (_uw) language_specific_data;

    ue_header->barrier_cache.bitpattern[3] = (_uw) landing_pad;

}

// Restore the catch handler data saved during phase1.

static inline void

restore_caught_exception(struct _Unwind_Exception* ue_header,

                         int& handler_switch_value,

                         const unsigned char*& language_specific_data,

                         _Unwind_Ptr& landing_pad)

{

  handler_switch_value = (int) ue_header->barrier_cache.bitpattern[1];

  language_specific_data =

    (const unsigned char*) ue_header->barrier_cache.bitpattern[2];

  landing_pad = (_Unwind_Ptr) ue_header->barrier_cache.bitpattern[3];

}

#define CONTINUE_UNWINDING \

  do                                                            \

    {                                                           \

      if (__gnu_unwind_frame(ue_header, context) != _URC_OK)    \

        return _URC_FAILURE;                                    \

      return _URC_CONTINUE_UNWIND;                              \

    }                                                           \

  while (0)

#else

typedef const std::type_info _throw_typet;

// Return an element from a type table.

static const std::type_info *

get_ttype_entry (lsda_header_info *info, _Unwind_Word i)

{

  _Unwind_Ptr ptr;

  i *= size_of_encoded_value (info->ttype_encoding);

  read_encoded_value_with_base (info->ttype_encoding, info->ttype_base,

                                info->TType - i, &ptr);

  return reinterpret_cast<const std::type_info *>(ptr);

}

// Given the thrown type THROW_TYPE, pointer to a variable containing a

// pointer to the exception object THROWN_PTR_P and a type CATCH_TYPE to

// compare against, return whether or not there is a match and if so,

// update *THROWN_PTR_P.

static bool

get_adjusted_ptr (const std::type_info *catch_type,

                  const std::type_info *throw_type,

                  void **thrown_ptr_p)

{

  void *thrown_ptr = *thrown_ptr_p;

  // Pointer types need to adjust the actual pointer, not

  // the pointer to pointer that is the exception object.

  // This also has the effect of passing pointer types

  // "by value" through the __cxa_begin_catch return value.

  if (throw_type->__is_pointer_p ())

    thrown_ptr = *(void **) thrown_ptr;

  if (catch_type->__do_catch (throw_type, &thrown_ptr, 1))

    {

      *thrown_ptr_p = thrown_ptr;

      return true;

    }

  return false;

}

// Return true if THROW_TYPE matches one if the filter types.

static bool

check_exception_spec(lsda_header_info* info, _throw_typet* throw_type,

                      void* thrown_ptr, _Unwind_Sword filter_value)

{

  const unsigned char *e = info->TType - filter_value - 1;

  while (1)

    {

      const std::type_info *catch_type;

      _Unwind_Word tmp;

      e = read_uleb128 (e, &tmp);

      // Zero signals the end of the list.  If we've not found

      // a match by now, then we've failed the specification.

      if (tmp == 0)

        return false;

      // Match a ttype entry.

      catch_type = get_ttype_entry (info, tmp);

      // ??? There is currently no way to ask the RTTI code about the

      // relationship between two types without reference to a specific

      // object.  There should be; then we wouldn't need to mess with

      // thrown_ptr here.

      if (get_adjusted_ptr (catch_type, throw_type, &thrown_ptr))

        return true;

    }

}

// Save stage1 handler information in the exception object

static inline void

save_caught_exception(struct _Unwind_Exception* ue_header,

                      struct _Unwind_Context* context

                        __attribute__((__unused__)),

                      void* thrown_ptr,

                      int handler_switch_value,

                      const unsigned char* language_specific_data,

                      _Unwind_Ptr landing_pad __attribute__((__unused__)),

                      const unsigned char* action_record)

{

  __cxa_exception* xh = __get_exception_header_from_ue(ue_header);

  xh->handlerSwitchValue = handler_switch_value;

  xh->actionRecord = action_record;

  xh->languageSpecificData = language_specific_data;

  xh->adjustedPtr = thrown_ptr;

  // ??? Completely unknown what this field is supposed to be for.

  // ??? Need to cache TType encoding base for call_unexpected.

  xh->catchTemp = landing_pad;

}

// Restore the catch handler information saved during phase1.

static inline void

restore_caught_exception(struct _Unwind_Exception* ue_header,

                         int& handler_switch_value,

                         const unsigned char*& language_specific_data,

                         _Unwind_Ptr& landing_pad)

{

  __cxa_exception* xh = __get_exception_header_from_ue(ue_header);

  handler_switch_value = xh->handlerSwitchValue;

  language_specific_data = xh->languageSpecificData;

  landing_pad = (_Unwind_Ptr) xh->catchTemp;

}

#define CONTINUE_UNWINDING return _URC_CONTINUE_UNWIND

#endif // !__ARM_EABI_UNWINDER__

// Return true if the filter spec is empty, ie throw().

static bool

empty_exception_spec (lsda_header_info *info, _Unwind_Sword filter_value)

{

  const unsigned char *e = info->TType - filter_value - 1;

  _Unwind_Word tmp;

  e = read_uleb128 (e, &tmp);

  return tmp == 0;

}

// Using a different personality function name causes link failures

// when trying to mix code using different exception handling models.

#ifdef _GLIBCXX_SJLJ_EXCEPTIONS

#define PERSONALITY_FUNCTION    __gxx_personality_sj0

#define __builtin_eh_return_data_regno(x) x

#else

#define PERSONALITY_FUNCTION    __gxx_personality_v0

#endif

extern "C" _Unwind_Reason_Code

#ifdef __ARM_EABI_UNWINDER__

PERSONALITY_FUNCTION (_Unwind_State state,

                      struct _Unwind_Exception* ue_header,

                      struct _Unwind_Context* context)

#else

PERSONALITY_FUNCTION (int version,

                      _Unwind_Action actions,

                      _Unwind_Exception_Class exception_class,

                      struct _Unwind_Exception *ue_header,

                      struct _Unwind_Context *context)

#endif

{

  enum found_handler_type

  {

    found_nothing,

    found_terminate,

    found_cleanup,

    found_handler

  } found_type;

  lsda_header_info info;

  const unsigned char *language_specific_data;

  const unsigned char *action_record;

  const unsigned char *p;

  _Unwind_Ptr landing_pad, ip;

  int handler_switch_value;

  void* thrown_ptr = ue_header + 1;

  bool foreign_exception;

#ifdef __ARM_EABI_UNWINDER__

  _Unwind_Action actions;

  switch (state & _US_ACTION_MASK)

    {

    case _US_VIRTUAL_UNWIND_FRAME:

      actions = _UA_SEARCH_PHASE;

      break;

    case _US_UNWIND_FRAME_STARTING:

      actions = _UA_CLEANUP_PHASE;

      if (!(state & _US_FORCE_UNWIND)

          && ue_header->barrier_cache.sp == _Unwind_GetGR(context, 13))

        actions |= _UA_HANDLER_FRAME;

      break;

    case _US_UNWIND_FRAME_RESUME:

      CONTINUE_UNWINDING;

      break;

    default:

      std::abort();

    }

  actions |= state & _US_FORCE_UNWIND;

  // We don't know which runtime we're working with, so can't check this.

  // However the ABI routines hide this from us, and we don't actually need

  // to know.

  foreign_exception = false;

  // The dwarf unwinder assumes the context structure holds things like the

  // function and LSDA pointers.  The ARM implementation caches these in

  // the exception header (UCB).  To avoid rewriting everything we make the

  // virtual IP register point at the UCB.

  ip = (_Unwind_Ptr) ue_header;

  _Unwind_SetGR(context, 12, ip);

#else

  __cxa_exception* xh = __get_exception_header_from_ue(ue_header);

  // Interface version check.

  if (version != 1)

    return _URC_FATAL_PHASE1_ERROR;

  foreign_exception = !__is_gxx_exception_class(exception_class);

#endif

  // Shortcut for phase 2 found handler for domestic exception.

  if (actions == (_UA_CLEANUP_PHASE | _UA_HANDLER_FRAME)

      && !foreign_exception)

    {

      restore_caught_exception(ue_header, handler_switch_value,

                               language_specific_data, landing_pad);

      found_type = (landing_pad == 0 ? found_terminate : found_handler);

      goto install_context;

    }

  language_specific_data = (const unsigned char *)

    _Unwind_GetLanguageSpecificData (context);

  // If no LSDA, then there are no handlers or cleanups.

  if (! language_specific_data)

    CONTINUE_UNWINDING;

  // Parse the LSDA header.

  p = parse_lsda_header (context, language_specific_data, &info);

  info.ttype_base = base_of_encoded_value (info.ttype_encoding, context);

  ip = _Unwind_GetIP (context) - 1;

  landing_pad = 0;

  action_record = 0;

  handler_switch_value = 0;

#ifdef _GLIBCXX_SJLJ_EXCEPTIONS

  // The given "IP" is an index into the call-site table, with two

  // exceptions -- -1 means no-action, and 0 means terminate.  But

  // since we're using uleb128 values, we've not got random access

  // to the array.

  if ((int) ip < 0)

    return _URC_CONTINUE_UNWIND;

  else if (ip == 0)

    {

      // Fall through to set found_terminate.

    }

  else

    {

      _Unwind_Word cs_lp, cs_action;

      do

        {

          p = read_uleb128 (p, &cs_lp);

          p = read_uleb128 (p, &cs_action);

        }

      while (--ip);

      // Can never have null landing pad for sjlj -- that would have

      // been indicated by a -1 call site index.

      landing_pad = cs_lp + 1;

      if (cs_action)

        action_record = info.action_table + cs_action - 1;

      goto found_something;

    }

#else

  // Search the call-site table for the action associated with this IP.

  while (p < info.action_table)

    {

      _Unwind_Ptr cs_start, cs_len, cs_lp;

      _Unwind_Word cs_action;

      // Note that all call-site encodings are "absolute" displacements.

      p = read_encoded_value (0, info.call_site_encoding, p, &cs_start);

      p = read_encoded_value (0, info.call_site_encoding, p, &cs_len);

      p = read_encoded_value (0, info.call_site_encoding, p, &cs_lp);

      p = read_uleb128 (p, &cs_action);

      // The table is sorted, so if we've passed the ip, stop.

      if (ip < info.Start + cs_start)

        p = info.action_table;

      else if (ip < info.Start + cs_start + cs_len)

        {

          if (cs_lp)

            landing_pad = info.LPStart + cs_lp;

          if (cs_action)

            action_record = info.action_table + cs_action - 1;

          goto found_something;

        }

    }

#endif // _GLIBCXX_SJLJ_EXCEPTIONS

  // If ip is not present in the table, call terminate.  This is for

  // a destructor inside a cleanup, or a library routine the compiler

  // was not expecting to throw.

  found_type = found_terminate;

  goto do_something;

 found_something:

  if (landing_pad == 0)

    {

      // If ip is present, and has a null landing pad, there are

      // no cleanups or handlers to be run.

      found_type = found_nothing;

    }

  else if (action_record == 0)

    {

      // If ip is present, has a non-null landing pad, and a null

      // action table offset, then there are only cleanups present.

      // Cleanups use a zero switch value, as set above.

      found_type = found_cleanup;

    }

  else

    {

      // Otherwise we have a catch handler or exception specification.

      _Unwind_Sword ar_filter, ar_disp;

      const std::type_info* catch_type;

      _throw_typet* throw_type;

      bool saw_cleanup = false;

      bool saw_handler = false;

      // During forced unwinding, we only run cleanups.  With a foreign

      // exception class, there's no exception type.

      // ??? What to do about GNU Java and GNU Ada exceptions.

      if ((actions & _UA_FORCE_UNWIND)

          || foreign_exception)

        throw_type = 0;

      else

#ifdef __ARM_EABI_UNWINDER__

        throw_type = ue_header;

#else

        throw_type = xh->exceptionType;

#endif

      while (1)

        {

          p = action_record;

          p = read_sleb128 (p, &ar_filter);

          read_sleb128 (p, &ar_disp);

          if (ar_filter == 0)

            {

              // Zero filter values are cleanups.

              saw_cleanup = true;

            }

          else if (ar_filter > 0)

            {

              // Positive filter values are handlers.

              catch_type = get_ttype_entry (&info, ar_filter);

              // Null catch type is a catch-all handler; we can catch foreign

              // exceptions with this.  Otherwise we must match types.

              if (! catch_type

                  || (throw_type

                      && get_adjusted_ptr (catch_type, throw_type,

                                           &thrown_ptr)))

                {

                  saw_handler = true;

                  break;

                }

            }

          else

            {

              // Negative filter values are exception specifications.

              // ??? How do foreign exceptions fit in?  As far as I can

              // see we can't match because there's no __cxa_exception

              // object to stuff bits in for __cxa_call_unexpected to use.

              // Allow them iff the exception spec is non-empty.  I.e.

              // a throw() specification results in __unexpected.

              if (throw_type

                  ? ! check_exception_spec (&info, throw_type, thrown_ptr,

                                            ar_filter)

                  : empty_exception_spec (&info, ar_filter))

                {

                  saw_handler = true;

                  break;

                }

            }

          if (ar_disp == 0)

            break;

          action_record = p + ar_disp;

        }

      if (saw_handler)

        {

          handler_switch_value = ar_filter;

          found_type = found_handler;

        }

      else

        found_type = (saw_cleanup ? found_cleanup : found_nothing);

    }

 do_something:

   if (found_type == found_nothing)

     CONTINUE_UNWINDING;

  if (actions & _UA_SEARCH_PHASE)

    {

      if (found_type == found_cleanup)

        CONTINUE_UNWINDING;

      // For domestic exceptions, we cache data from phase 1 for phase 2.

      if (!foreign_exception)

        {

          save_caught_exception(ue_header, context, thrown_ptr,

                                handler_switch_value, language_specific_data,

                                landing_pad, action_record);

        }

      return _URC_HANDLER_FOUND;

    }

 install_context:

  // We can't use any of the cxa routines with foreign exceptions,

  // because they all expect ue_header to be a struct __cxa_exception.

  // So in that case, call terminate or unexpected directly.

  if ((actions & _UA_FORCE_UNWIND)

      || foreign_exception)

    {

      if (found_type == found_terminate)

        std::terminate ();

      else if (handler_switch_value < 0)

        {

          try

            { std::unexpected (); }

          catch(...)

            { std::terminate (); }

        }

    }

  else

    {

      if (found_type == found_terminate)

        __cxa_call_terminate(ue_header);

      // Cache the TType base value for __cxa_call_unexpected, as we won't

      // have an _Unwind_Context then.

      if (handler_switch_value < 0)

        {

          parse_lsda_header (context, language_specific_data, &info);

#ifdef __ARM_EABI_UNWINDER__

          const _Unwind_Word* e;

          _Unwind_Word n;

          e = ((const _Unwind_Word*) info.TType) - handler_switch_value - 1;

          // Count the number of rtti objects.

          n = 0;

          while (e[n] != 0)

            n++;

          // Count.

          ue_header->barrier_cache.bitpattern[1] = n;

          // Base (obsolete)

          ue_header->barrier_cache.bitpattern[2] = 0;

          // Stride.

          ue_header->barrier_cache.bitpattern[3] = 4;

          // List head.

          ue_header->barrier_cache.bitpattern[4] = (_Unwind_Word) e;

#else

          xh->catchTemp = base_of_encoded_value (info.ttype_encoding, context);

#endif

        }

    }

  /* For targets with pointers smaller than the word size, we must extend the

     pointer, and this extension is target dependent.  */

  _Unwind_SetGR (context, __builtin_eh_return_data_regno (0),

                 __builtin_extend_pointer (ue_header));

  _Unwind_SetGR (context, __builtin_eh_return_data_regno (1),

                 handler_switch_value);

  _Unwind_SetIP (context, landing_pad);

#ifdef __ARM_EABI_UNWINDER__

  if (found_type == found_cleanup)

    __cxa_begin_cleanup(ue_header);

#endif

  return _URC_INSTALL_CONTEXT;

}

/* The ARM EABI implementation of __cxa_call_unexpected is in a different

   file so that the personality routine san be used standalone.  The generic

   routine sahred datastructures with the PR so it is most convenient to

   implement it here.  */

#ifndef __ARM_EABI_UNWINDER__

extern "C" void

__cxa_call_unexpected (void *exc_obj_in)

{

  _Unwind_Exception *exc_obj

    = reinterpret_cast <_Unwind_Exception *>(exc_obj_in);

  __cxa_begin_catch (exc_obj);

  // This function is a handler for our exception argument.  If we exit

  // by throwing a different exception, we'll need the original cleaned up.

  struct end_catch_protect

  {

    end_catch_protect() { }

    ~end_catch_protect() { __cxa_end_catch(); }

  } end_catch_protect_obj;

  lsda_header_info info;

  __cxa_exception *xh = __get_exception_header_from_ue (exc_obj);

  const unsigned char *xh_lsda;

  _Unwind_Sword xh_switch_value;

  std::terminate_handler xh_terminate_handler;

  // If the unexpectedHandler rethrows the exception (e.g. to categorize it),

  // it will clobber data about the current handler.  So copy the data out now.

  xh_lsda = xh->languageSpecificData;

  xh_switch_value = xh->handlerSwitchValue;

  xh_terminate_handler = xh->terminateHandler;