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 foreign_exception = !__is_gxx_exception_class(ue_header->exception_class);
  50   __cxa_exception* xh = __get_exception_header_from_ue(ue_header);
  51   const std::type_info* throw_type;
  52
  53   // XXX What to do with forced unwind?
  54   if (foreign_exception)
  55     throw_type = &typeid(abi::__foreign_exception);
  56   else
  57     throw_type = xh->exceptionType;
  58
  59   void* thrown_ptr = *thrown_ptr_p;
  60
  61   // Pointer types need to adjust the actual pointer, not
  62   // the pointer to pointer that is the exception object.
  63   // This also has the effect of passing pointer types
  64   // "by value" through the __cxa_begin_catch return value.
  65   if (throw_type->__is_pointer_p())
  66     thrown_ptr = *(void**) thrown_ptr;
  67
  68   if (catch_type->__do_catch(throw_type, &thrown_ptr, 1))
  69     {
  70       *thrown_ptr_p = thrown_ptr;
  71
  72       if (typeid(*catch_type) == typeid (typeid(void*)))
  73         {
  74           const __pointer_type_info *catch_pointer_type =
  75             static_cast<const __pointer_type_info *> (catch_type);
  76           const __pointer_type_info *throw_pointer_type =
  77             static_cast<const __pointer_type_info *> (throw_type);
  78
  79           if (typeid (*catch_pointer_type->__pointee) != typeid (void)
  80               && (*catch_pointer_type->__pointee !=
  81                   *throw_pointer_type->__pointee))
  82             return ctm_succeeded_with_ptr_to_base;
  83         }
  84
  85       return ctm_succeeded;
  86     }
  87
  88   return ctm_failed;
  89 }
  90
  91 // ABI defined routine called at the start of a cleanup handler.
  92 extern "C" bool
  93 __cxa_begin_cleanup(_Unwind_Exception* ue_header)
  94 {
  95   __cxa_eh_globals *globals = __cxa_get_globals();
  96   __cxa_exception *header = __get_exception_header_from_ue(ue_header);
  97   bool native = __is_gxx_exception_class(header->unwindHeader.exception_class);
  98
  99
 100   if (native)
 101     {
 102       header->propagationCount++;
 103       // Add it to the chain if this is the first time we've seen this
 104       // exception.
 105       if (header->propagationCount == 1)
 106         {
 107           header->nextPropagatingException = globals->propagatingExceptions;
 108           globals->propagatingExceptions = header;
 109         }
 110     }
 111   else
 112     {
 113       // Remember the exception object, so end_cleanup can return it.
 114       // These cannot be stacked, so we must abort if we already have
 115       // a propagating exception.
 116       if (globals->propagatingExceptions)
 117         std::terminate ();
 118       globals->propagatingExceptions = header;
 119     }
 120
 121   return true;
 122 }
 123
 124 // Do the work for __cxa_end_cleanup.  Returns the currently propagating
 125 // exception object.
 126 extern "C" _Unwind_Exception *
 127 __gnu_end_cleanup(void)
 128 {
 129   __cxa_exception *header;
 130   __cxa_eh_globals *globals = __cxa_get_globals();
 131
 132   header = globals->propagatingExceptions;
 133
 134   // Check something hasn't gone horribly wrong.
 135   if (!header)
 136     std::terminate();
 137
 138   if (__is_gxx_exception_class(header->unwindHeader.exception_class))
 139     {
 140       header->propagationCount--;
 141       if (header->propagationCount == 0)
 142         {
 143           // Remove exception from chain.
 144           globals->propagatingExceptions = header->nextPropagatingException;
 145           header->nextPropagatingException = NULL;
 146         }
 147     }
 148   else
 149     globals->propagatingExceptions = NULL;
 150
 151   return &header->unwindHeader;
 152 }
 153
 154 // Assembly wrapper to call __gnu_end_cleanup without clobbering r1-r3.
 155 // Also push r4 to preserve stack alignment.
 156 #ifdef __thumb__
 157 asm (".global __cxa_end_cleanup\n"
 158 "       .type __cxa_end_cleanup, \"function\"\n"
 159 "       .thumb_func\n"
 160 "__cxa_end_cleanup:\n"
 161 "       push\t{r1, r2, r3, r4}\n"
 162 "       bl\t__gnu_end_cleanup\n"
 163 "       pop\t{r1, r2, r3, r4}\n"
 164 "       bl\t_Unwind_Resume @ Never returns\n");
 165 #else
 166 asm (".global __cxa_end_cleanup\n"
 167 "       .type __cxa_end_cleanup, \"function\"\n"
 168 "__cxa_end_cleanup:\n"
 169 "       stmfd\tsp!, {r1, r2, r3, r4}\n"
 170 "       bl\t__gnu_end_cleanup\n"
 171 "       ldmfd\tsp!, {r1, r2, r3, r4}\n"
 172 "       bl\t_Unwind_Resume @ Never returns\n");
 173 #endif
 174
 175 #endif