libstdc++-v3/libsupc++/eh_arm.cc

   1 // -*- C++ -*- ARM specific Exception handling support routines.
   2 // Copyright (C) 2004, 2005 Free Software Foundation, Inc.
   3 //
   4 // This file is part of GCC.
   5 //
   6 // GCC is free software; you can redistribute it and/or modify
   7 // it under the terms of the GNU General Public License as published by
   8 // the Free Software Foundation; either version 2, or (at your option)
   9 // any later version.
  10 //
  11 // GCC is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15 //
  16 // You should have received a copy of the GNU General Public License
  17 // along with GCC; see the file COPYING.  If not, write to
  18 // the Free Software Foundation, 51 Franklin Street, Fifth Floor,
  19 // Boston, MA 02110-1301, USA.
  20
  21 // As a special exception, you may use this file as part of a free software
  22 // library without restriction.  Specifically, if other files instantiate
  23 // templates or use macros or inline functions from this file, or you compile
  24 // this file and link it with other files to produce an executable, this
  25 // file does not by itself cause the resulting executable to be covered by
  26 // the GNU General Public License.  This exception does not however
  27 // invalidate any other reasons why the executable file might be covered by
  28 // the GNU General Public License.
  29
  30 #include <cxxabi.h>
  31 #include "unwind-cxx.h"
  32
  33 #ifdef __ARM_EABI_UNWINDER__
  34
  35 using namespace __cxxabiv1;
  36
  37
  38 // Given the thrown type THROW_TYPE, pointer to a variable containing a
  39 // pointer to the exception object THROWN_PTR_P and a type CATCH_TYPE to
  40 // compare against, return whether or not there is a match and if so,
  41 // update *THROWN_PTR_P.
  42
  43 extern "C" __cxa_type_match_result
  44 __cxa_type_match(_Unwind_Exception* ue_header,
  45                  const std::type_info* catch_type,
  46                  bool is_reference __attribute__((__unused__)),
  47                  void** thrown_ptr_p)
  48 {
  49   bool forced_unwind = __is_gxx_forced_unwind_class(ue_header->exception_class);
  50   bool foreign_exception = !forced_unwind && !__is_gxx_exception_class(ue_header->exception_class);
  51   __cxa_exception* xh = __get_exception_header_from_ue(ue_header);
  52   const std::type_info* throw_type;
  53
  54   if (forced_unwind)
  55     throw_type = &typeid(abi::__forced_unwind);
  56   else if (foreign_exception)
  57     throw_type = &typeid(abi::__foreign_exception);
  58   else
  59     throw_type = xh->exceptionType;
  60
  61   void* thrown_ptr = *thrown_ptr_p;
  62
  63   // Pointer types need to adjust the actual pointer, not
  64   // the pointer to pointer that is the exception object.
  65   // This also has the effect of passing pointer types
  66   // "by value" through the __cxa_begin_catch return value.
  67   if (throw_type->__is_pointer_p())
  68     thrown_ptr = *(void**) thrown_ptr;
  69
  70   if (catch_type->__do_catch(throw_type, &thrown_ptr, 1))
  71     {
  72       *thrown_ptr_p = thrown_ptr;
  73
  74       if (typeid(*catch_type) == typeid (typeid(void*)))
  75         {
  76           const __pointer_type_info *catch_pointer_type =
  77             static_cast<const __pointer_type_info *> (catch_type);
  78           const __pointer_type_info *throw_pointer_type =
  79             static_cast<const __pointer_type_info *> (throw_type);
  80
  81           if (typeid (*catch_pointer_type->__pointee) != typeid (void)
  82               && (*catch_pointer_type->__pointee !=
  83                   *throw_pointer_type->__pointee))
  84             return ctm_succeeded_with_ptr_to_base;
  85         }
  86
  87       return ctm_succeeded;
  88     }
  89
  90   return ctm_failed;
  91 }
  92
  93 // ABI defined routine called at the start of a cleanup handler.
  94 extern "C" bool
  95 __cxa_begin_cleanup(_Unwind_Exception* ue_header)
  96 {
  97   __cxa_eh_globals *globals = __cxa_get_globals();
  98   __cxa_exception *header = __get_exception_header_from_ue(ue_header);
  99   bool native = __is_gxx_exception_class(header->unwindHeader.exception_class);
 100
 101
 102   if (native)
 103     {
 104       header->propagationCount++;
 105       // Add it to the chain if this is the first time we've seen this
 106       // exception.
 107       if (header->propagationCount == 1)
 108         {
 109           header->nextPropagatingException = globals->propagatingExceptions;
 110           globals->propagatingExceptions = header;
 111         }
 112     }
 113   else
 114     {
 115       // Remember the exception object, so end_cleanup can return it.
 116       // These cannot be stacked, so we must abort if we already have
 117       // a propagating exception.
 118       if (globals->propagatingExceptions)
 119         std::terminate ();
 120       globals->propagatingExceptions = header;
 121     }
 122
 123   return true;
 124 }
 125
 126 // Do the work for __cxa_end_cleanup.  Returns the currently propagating
 127 // exception object.
 128 extern "C" _Unwind_Exception *
 129 __gnu_end_cleanup(void)
 130 {
 131   __cxa_exception *header;
 132   __cxa_eh_globals *globals = __cxa_get_globals();
 133
 134   header = globals->propagatingExceptions;
 135
 136   // Check something hasn't gone horribly wrong.
 137   if (!header)
 138     std::terminate();
 139
 140   if (__is_gxx_exception_class(header->unwindHeader.exception_class))
 141     {
 142       header->propagationCount--;
 143       if (header->propagationCount == 0)
 144         {
 145           // Remove exception from chain.
 146           globals->propagatingExceptions = header->nextPropagatingException;
 147           header->nextPropagatingException = NULL;
 148         }
 149     }
 150   else
 151     globals->propagatingExceptions = NULL;
 152
 153   return &header->unwindHeader;
 154 }
 155
 156 // Assembly wrapper to call __gnu_end_cleanup without clobbering r1-r3.
 157 // Also push r4 to preserve stack alignment.
 158 #ifdef __thumb__
 159 asm (".global __cxa_end_cleanup\n"
 160 "       .type __cxa_end_cleanup, \"function\"\n"
 161 "       .thumb_func\n"
 162 "__cxa_end_cleanup:\n"
 163 "       push\t{r1, r2, r3, r4}\n"
 164 "       bl\t__gnu_end_cleanup\n"
 165 "       pop\t{r1, r2, r3, r4}\n"
 166 "       bl\t_Unwind_Resume @ Never returns\n");
 167 #else
 168 asm (".global __cxa_end_cleanup\n"
 169 "       .type __cxa_end_cleanup, \"function\"\n"
 170 "__cxa_end_cleanup:\n"
 171 "       stmfd\tsp!, {r1, r2, r3, r4}\n"
 172 "       bl\t__gnu_end_cleanup\n"
 173 "       ldmfd\tsp!, {r1, r2, r3, r4}\n"
 174 "       bl\t_Unwind_Resume @ Never returns\n");
 175 #endif
 176
 177 #endif