contrib/gcc-4.4/libstdc++-v3/libsupc++/eh_arm.cc

   1 // -*- C++ -*- ARM specific Exception handling support routines.
   2 // Copyright (C) 2004, 2005, 2008, 2009 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 3, 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 // Under Section 7 of GPL version 3, you are granted additional
  17 // permissions described in the GCC Runtime Library Exception, version
  18 // 3.1, as published by the Free Software Foundation.
  19 //
  20 // You should have received a copy of the GNU General Public License and
  21 // a copy of the GCC Runtime Library Exception along with this program;
  22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 // <http://www.gnu.org/licenses/>.
  24
  25 #include <cxxabi.h>
  26 #include "unwind-cxx.h"
  27
  28 #ifdef __ARM_EABI_UNWINDER__
  29
  30 using namespace __cxxabiv1;
  31
  32
  33 // Given the thrown type THROW_TYPE, pointer to a variable containing a
  34 // pointer to the exception object THROWN_PTR_P and a type CATCH_TYPE to
  35 // compare against, return whether or not there is a match and if so,
  36 // update *THROWN_PTR_P.
  37
  38 extern "C" __cxa_type_match_result
  39 __cxa_type_match(_Unwind_Exception* ue_header,
  40                  const std::type_info* catch_type,
  41                  bool is_reference __attribute__((__unused__)),
  42                  void** thrown_ptr_p)
  43 {
  44   bool forced_unwind = __is_gxx_forced_unwind_class(ue_header->exception_class);
  45   bool foreign_exception = !forced_unwind && !__is_gxx_exception_class(ue_header->exception_class);
  46   bool dependent_exception =
  47     __is_dependent_exception(ue_header->exception_class);
  48   __cxa_exception* xh = __get_exception_header_from_ue(ue_header);
  49   __cxa_dependent_exception *dx = __get_dependent_exception_from_ue(ue_header);
  50   const std::type_info* throw_type;
  51
  52   if (forced_unwind)
  53     throw_type = &typeid(abi::__forced_unwind);
  54   else if (foreign_exception)
  55     throw_type = &typeid(abi::__foreign_exception);
  56   else if (dependent_exception)
  57     throw_type = __get_exception_header_from_obj
  58       (dx->primaryException)->exceptionType;
  59   else
  60     throw_type = xh->exceptionType;
  61
  62   void* thrown_ptr = *thrown_ptr_p;
  63
  64   // Pointer types need to adjust the actual pointer, not
  65   // the pointer to pointer that is the exception object.
  66   // This also has the effect of passing pointer types
  67   // "by value" through the __cxa_begin_catch return value.
  68   if (throw_type->__is_pointer_p())
  69     thrown_ptr = *(void**) thrown_ptr;
  70
  71   if (catch_type->__do_catch(throw_type, &thrown_ptr, 1))
  72     {
  73       *thrown_ptr_p = thrown_ptr;
  74
  75       if (typeid(*catch_type) == typeid (typeid(void*)))
  76         {
  77           const __pointer_type_info *catch_pointer_type =
  78             static_cast<const __pointer_type_info *> (catch_type);
  79           const __pointer_type_info *throw_pointer_type =
  80             static_cast<const __pointer_type_info *> (throw_type);
  81
  82           if (typeid (*catch_pointer_type->__pointee) != typeid (void)
  83               && (*catch_pointer_type->__pointee !=
  84                   *throw_pointer_type->__pointee))
  85             return ctm_succeeded_with_ptr_to_base;
  86         }
  87
  88       return ctm_succeeded;
  89     }
  90
  91   return ctm_failed;
  92 }
  93
  94 // ABI defined routine called at the start of a cleanup handler.
  95 extern "C" bool
  96 __cxa_begin_cleanup(_Unwind_Exception* ue_header)
  97 {
  98   __cxa_eh_globals *globals = __cxa_get_globals();
  99   __cxa_exception *header = __get_exception_header_from_ue(ue_header);
 100   bool native = __is_gxx_exception_class(header->unwindHeader.exception_class);
 101
 102
 103   if (native)
 104     {
 105       header->propagationCount++;
 106       // Add it to the chain if this is the first time we've seen this
 107       // exception.
 108       if (header->propagationCount == 1)
 109         {
 110           header->nextPropagatingException = globals->propagatingExceptions;
 111           globals->propagatingExceptions = header;
 112         }
 113     }
 114   else
 115     {
 116       // Remember the exception object, so end_cleanup can return it.
 117       // These cannot be stacked, so we must abort if we already have
 118       // a propagating exception.
 119       if (globals->propagatingExceptions)
 120         std::terminate ();
 121       globals->propagatingExceptions = header;
 122     }
 123
 124   return true;
 125 }
 126
 127 // Do the work for __cxa_end_cleanup.  Returns the currently propagating
 128 // exception object.
 129 extern "C" _Unwind_Exception *
 130 __gnu_end_cleanup(void)
 131 {
 132   __cxa_exception *header;
 133   __cxa_eh_globals *globals = __cxa_get_globals();
 134
 135   header = globals->propagatingExceptions;
 136
 137   // Check something hasn't gone horribly wrong.
 138   if (!header)
 139     std::terminate();
 140
 141   if (__is_gxx_exception_class(header->unwindHeader.exception_class))
 142     {
 143       header->propagationCount--;
 144       if (header->propagationCount == 0)
 145         {
 146           // Remove exception from chain.
 147           globals->propagatingExceptions = header->nextPropagatingException;
 148           header->nextPropagatingException = NULL;
 149         }
 150     }
 151   else
 152     globals->propagatingExceptions = NULL;
 153
 154   return &header->unwindHeader;
 155 }
 156
 157 // Assembly wrapper to call __gnu_end_cleanup without clobbering r1-r3.
 158 // Also push r4 to preserve stack alignment.
 159 #ifdef __thumb__
 160 asm (".global __cxa_end_cleanup\n"
 161 "       .type __cxa_end_cleanup, \"function\"\n"
 162 "       .thumb_func\n"
 163 "__cxa_end_cleanup:\n"
 164 "       push\t{r1, r2, r3, r4}\n"
 165 "       bl\t__gnu_end_cleanup\n"
 166 "       pop\t{r1, r2, r3, r4}\n"
 167 "       bl\t_Unwind_Resume @ Never returns\n");
 168 #else
 169 asm (".global __cxa_end_cleanup\n"
 170 "       .type __cxa_end_cleanup, \"function\"\n"
 171 "__cxa_end_cleanup:\n"
 172 "       stmfd\tsp!, {r1, r2, r3, r4}\n"
 173 "       bl\t__gnu_end_cleanup\n"
 174 "       ldmfd\tsp!, {r1, r2, r3, r4}\n"
 175 "       bl\t_Unwind_Resume @ Never returns\n");
 176 #endif
 177
 178 #endif