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

   1 // -*- C++ -*- ARM specific Exception handling support routines.
   2 // Copyright (C) 2004, 2005, 2008 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   bool dependent_exception =
  52     __is_dependent_exception(ue_header->exception_class);
  53   __cxa_exception* xh = __get_exception_header_from_ue(ue_header);
  54   __cxa_dependent_exception *dx = __get_dependent_exception_from_ue(ue_header);
  55   const std::type_info* throw_type;
  56
  57   if (forced_unwind)
  58     throw_type = &typeid(abi::__forced_unwind);
  59   else if (foreign_exception)
  60     throw_type = &typeid(abi::__foreign_exception);
  61   else if (dependent_exception)
  62     throw_type = __get_exception_header_from_obj
  63       (dx->primaryException)->exceptionType;
  64   else
  65     throw_type = xh->exceptionType;
  66
  67   void* thrown_ptr = *thrown_ptr_p;
  68
  69   // Pointer types need to adjust the actual pointer, not
  70   // the pointer to pointer that is the exception object.
  71   // This also has the effect of passing pointer types
  72   // "by value" through the __cxa_begin_catch return value.
  73   if (throw_type->__is_pointer_p())
  74     thrown_ptr = *(void**) thrown_ptr;
  75
  76   if (catch_type->__do_catch(throw_type, &thrown_ptr, 1))
  77     {
  78       *thrown_ptr_p = thrown_ptr;
  79
  80       if (typeid(*catch_type) == typeid (typeid(void*)))
  81         {
  82           const __pointer_type_info *catch_pointer_type =
  83             static_cast<const __pointer_type_info *> (catch_type);
  84           const __pointer_type_info *throw_pointer_type =
  85             static_cast<const __pointer_type_info *> (throw_type);
  86
  87           if (typeid (*catch_pointer_type->__pointee) != typeid (void)
  88               && (*catch_pointer_type->__pointee !=
  89                   *throw_pointer_type->__pointee))
  90             return ctm_succeeded_with_ptr_to_base;
  91         }
  92
  93       return ctm_succeeded;
  94     }
  95
  96   return ctm_failed;
  97 }
  98
  99 // ABI defined routine called at the start of a cleanup handler.
 100 extern "C" bool
 101 __cxa_begin_cleanup(_Unwind_Exception* ue_header)
 102 {
 103   __cxa_eh_globals *globals = __cxa_get_globals();
 104   __cxa_exception *header = __get_exception_header_from_ue(ue_header);
 105   bool native = __is_gxx_exception_class(header->unwindHeader.exception_class);
 106
 107
 108   if (native)
 109     {
 110       header->propagationCount++;
 111       // Add it to the chain if this is the first time we've seen this
 112       // exception.
 113       if (header->propagationCount == 1)
 114         {
 115           header->nextPropagatingException = globals->propagatingExceptions;
 116           globals->propagatingExceptions = header;
 117         }
 118     }
 119   else
 120     {
 121       // Remember the exception object, so end_cleanup can return it.
 122       // These cannot be stacked, so we must abort if we already have
 123       // a propagating exception.
 124       if (globals->propagatingExceptions)
 125         std::terminate ();
 126       globals->propagatingExceptions = header;
 127     }
 128
 129   return true;
 130 }
 131
 132 // Do the work for __cxa_end_cleanup.  Returns the currently propagating
 133 // exception object.
 134 extern "C" _Unwind_Exception *
 135 __gnu_end_cleanup(void)
 136 {
 137   __cxa_exception *header;
 138   __cxa_eh_globals *globals = __cxa_get_globals();
 139
 140   header = globals->propagatingExceptions;
 141
 142   // Check something hasn't gone horribly wrong.
 143   if (!header)
 144     std::terminate();
 145
 146   if (__is_gxx_exception_class(header->unwindHeader.exception_class))
 147     {
 148       header->propagationCount--;
 149       if (header->propagationCount == 0)
 150         {
 151           // Remove exception from chain.
 152           globals->propagatingExceptions = header->nextPropagatingException;
 153           header->nextPropagatingException = NULL;
 154         }
 155     }
 156   else
 157     globals->propagatingExceptions = NULL;
 158
 159   return &header->unwindHeader;
 160 }
 161
 162 // Assembly wrapper to call __gnu_end_cleanup without clobbering r1-r3.
 163 // Also push r4 to preserve stack alignment.
 164 #ifdef __thumb__
 165 asm (".global __cxa_end_cleanup\n"
 166 "       .type __cxa_end_cleanup, \"function\"\n"
 167 "       .thumb_func\n"
 168 "__cxa_end_cleanup:\n"
 169 "       push\t{r1, r2, r3, r4}\n"
 170 "       bl\t__gnu_end_cleanup\n"
 171 "       pop\t{r1, r2, r3, r4}\n"
 172 "       bl\t_Unwind_Resume @ Never returns\n");
 173 #else
 174 asm (".global __cxa_end_cleanup\n"
 175 "       .type __cxa_end_cleanup, \"function\"\n"
 176 "__cxa_end_cleanup:\n"
 177 "       stmfd\tsp!, {r1, r2, r3, r4}\n"
 178 "       bl\t__gnu_end_cleanup\n"
 179 "       ldmfd\tsp!, {r1, r2, r3, r4}\n"
 180 "       bl\t_Unwind_Resume @ Never returns\n");
 181 #endif
 182
 183 #endif