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   if (!__is_gxx_exception_class(ue_header->exception_class))
  50     return ctm_failed;
  51
  52   __cxa_exception* xh = __get_exception_header_from_ue(ue_header);
  53   const std::type_info* throw_type = xh->exceptionType;
  54   void* thrown_ptr = *thrown_ptr_p;
  55
  56   // Pointer types need to adjust the actual pointer, not
  57   // the pointer to pointer that is the exception object.
  58   // This also has the effect of passing pointer types
  59   // "by value" through the __cxa_begin_catch return value.
  60   if (throw_type->__is_pointer_p())
  61     thrown_ptr = *(void**) thrown_ptr;
  62
  63   if (catch_type->__do_catch(throw_type, &thrown_ptr, 1))
  64     {
  65       *thrown_ptr_p = thrown_ptr;
  66
  67       if (typeid(*catch_type) == typeid (typeid(void*)))
  68         {
  69           const __pointer_type_info *catch_pointer_type =
  70             static_cast<const __pointer_type_info *> (catch_type);
  71           const __pointer_type_info *throw_pointer_type =
  72             static_cast<const __pointer_type_info *> (throw_type);
  73
  74           if (typeid (*catch_pointer_type->__pointee) != typeid (void)
  75               && (*catch_pointer_type->__pointee !=
  76                   *throw_pointer_type->__pointee))
  77             return ctm_succeeded_with_ptr_to_base;
  78         }
  79
  80       return ctm_succeeded;
  81     }
  82
  83   return ctm_failed;
  84 }
  85
  86 // ABI defined routine called at the start of a cleanup handler.
  87 extern "C" bool
  88 __cxa_begin_cleanup(_Unwind_Exception* ue_header)
  89 {
  90   __cxa_eh_globals *globals = __cxa_get_globals();
  91   __cxa_exception *header = __get_exception_header_from_ue(ue_header);
  92
  93   if (!__is_gxx_exception_class(header->unwindHeader.exception_class))
  94     {
  95       // TODO: cleanups with foreign exceptions.
  96       return false;
  97     }
  98   header->propagationCount++;
  99   // Add it to the chain if this is the first time we've seen this exception.
 100   if (header->propagationCount == 1)
 101     {
 102       header->nextPropagatingException = globals->propagatingExceptions;
 103       globals->propagatingExceptions = header;
 104     }
 105   return true;
 106 }
 107
 108 // Do the work for __cxa_end_cleanup.  Returns the currently propagating
 109 // exception object.
 110 extern "C" _Unwind_Exception *
 111 __gnu_end_cleanup(void)
 112 {
 113   __cxa_exception *header;
 114   __cxa_eh_globals *globals = __cxa_get_globals();
 115
 116   header = globals->propagatingExceptions;
 117
 118   // Check something hasn't gone horribly wrong.
 119   if (!header)
 120     std::terminate();
 121
 122   header->propagationCount--;
 123   if (header->propagationCount == 0)
 124     {
 125       // Remove exception from chain.
 126       globals->propagatingExceptions = header->nextPropagatingException;
 127       header->nextPropagatingException = NULL;
 128     }
 129   return &header->unwindHeader;
 130 }
 131
 132 // Assembly wrapper to call __gnu_end_cleanup without clobbering r1-r3.
 133 // Also push r4 to preserve stack alignment.
 134 #ifdef __thumb__
 135 asm (".global __cxa_end_cleanup\n"
 136 "       .type __cxa_end_cleanup, \"function\"\n"
 137 "       .thumb_func\n"
 138 "__cxa_end_cleanup:\n"
 139 "       push\t{r1, r2, r3, r4}\n"
 140 "       bl\t__gnu_end_cleanup\n"
 141 "       pop\t{r1, r2, r3, r4}\n"
 142 "       bl\t_Unwind_Resume @ Never returns\n");
 143 #else
 144 asm (".global __cxa_end_cleanup\n"
 145 "       .type __cxa_end_cleanup, \"function\"\n"
 146 "__cxa_end_cleanup:\n"
 147 "       stmfd\tsp!, {r1, r2, r3, r4}\n"
 148 "       bl\t__gnu_end_cleanup\n"
 149 "       ldmfd\tsp!, {r1, r2, r3, r4}\n"
 150 "       bl\t_Unwind_Resume @ Never returns\n");
 151 #endif
 152
 153 #endif