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

   1 // -*- C++ -*- ARM specific Exception handling support routines.
   2 // Copyright (C) 2004, 2005, 2008, 2009, 2010 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, exception object UE_HEADER and a
  34 // type CATCH_TYPE to compare against, return whether or not there is
  35 // a match and if so, update *THROWN_PTR_P to point to either the
  36 // type-matched object, or in the case of a pointer type, the object
  37 // pointed to by the pointer.
  38
  39 extern "C" __cxa_type_match_result
  40 __cxa_type_match(_Unwind_Exception* ue_header,
  41                  const std::type_info* catch_type,
  42                  bool is_reference __attribute__((__unused__)),
  43                  void** thrown_ptr_p)
  44 {
  45   bool forced_unwind
  46     = __is_gxx_forced_unwind_class(ue_header->exception_class);
  47   bool foreign_exception
  48     = !forced_unwind && !__is_gxx_exception_class(ue_header->exception_class);
  49   bool dependent_exception
  50     = __is_dependent_exception(ue_header->exception_class);
  51   __cxa_exception* xh = __get_exception_header_from_ue(ue_header);
  52   __cxa_dependent_exception *dx = __get_dependent_exception_from_ue(ue_header);
  53   const std::type_info* throw_type;
  54   void *thrown_ptr = 0;
  55
  56   if (forced_unwind)
  57     throw_type = &typeid(abi::__forced_unwind);
  58   else if (foreign_exception)
  59     throw_type = &typeid(abi::__foreign_exception);
  60   else
  61     {
  62       if (dependent_exception)
  63         xh = __get_exception_header_from_obj (dx->primaryException);
  64       throw_type = xh->exceptionType;
  65       // We used to require the caller set the target of thrown_ptr_p,
  66       // but that's incorrect -- the EHABI makes no such requirement
  67       // -- and not all callers will set it.  Fortunately callers that
  68       // do initialize will always pass us the value we calculate
  69       // here, so there's no backwards compatibility problem.
  70       thrown_ptr = __get_object_from_ue (ue_header);
  71     }
  72
  73   __cxa_type_match_result result = ctm_succeeded;
  74
  75   // Pointer types need to adjust the actual pointer, not
  76   // the pointer to pointer that is the exception object.
  77   // This also has the effect of passing pointer types
  78   // "by value" through the __cxa_begin_catch return value.
  79   if (throw_type->__is_pointer_p())
  80     {
  81       thrown_ptr = *(void**) thrown_ptr;
  82       // We need to indicate the indirection to our caller.
  83       result = ctm_succeeded_with_ptr_to_base;
  84     }
  85
  86   if (catch_type->__do_catch(throw_type, &thrown_ptr, 1))
  87     {
  88       *thrown_ptr_p = thrown_ptr;
  89       return result;
  90     }
  91
  92   return ctm_failed;
  93 }
  94
  95 // ABI defined routine called at the start of a cleanup handler.
  96 extern "C" bool
  97 __cxa_begin_cleanup(_Unwind_Exception* ue_header)
  98 {
  99   __cxa_eh_globals *globals = __cxa_get_globals();
 100   __cxa_exception *header = __get_exception_header_from_ue(ue_header);
 101   bool native = __is_gxx_exception_class(header->unwindHeader.exception_class);
 102
 103
 104   if (native)
 105     {
 106       header->propagationCount++;
 107       // Add it to the chain if this is the first time we've seen this
 108       // exception.
 109       if (header->propagationCount == 1)
 110         {
 111           header->nextPropagatingException = globals->propagatingExceptions;
 112           globals->propagatingExceptions = header;
 113         }
 114     }
 115   else
 116     {
 117       // Remember the exception object, so end_cleanup can return it.
 118       // These cannot be stacked, so we must abort if we already have
 119       // a propagating exception.
 120       if (globals->propagatingExceptions)
 121         std::terminate ();
 122       globals->propagatingExceptions = header;
 123     }
 124
 125   return true;
 126 }
 127
 128 // Do the work for __cxa_end_cleanup.  Returns the currently propagating
 129 // exception object.
 130 extern "C" _Unwind_Exception *
 131 __gnu_end_cleanup(void)
 132 {
 133   __cxa_exception *header;
 134   __cxa_eh_globals *globals = __cxa_get_globals();
 135
 136   header = globals->propagatingExceptions;
 137
 138   // Check something hasn't gone horribly wrong.
 139   if (!header)
 140     std::terminate();
 141
 142   if (__is_gxx_exception_class(header->unwindHeader.exception_class))
 143     {
 144       header->propagationCount--;
 145       if (header->propagationCount == 0)
 146         {
 147           // Remove exception from chain.
 148           globals->propagatingExceptions = header->nextPropagatingException;
 149           header->nextPropagatingException = NULL;
 150         }
 151     }
 152   else
 153     globals->propagatingExceptions = NULL;
 154
 155   return &header->unwindHeader;
 156 }
 157
 158 #ifdef __TMS320C6X__
 159 // Assembly wrapper to call __gnu_end_cleanup without clobbering
 160 // function arguments to _Unwind_Resume.
 161 asm (".global __cxa_end_cleanup\n"
 162 "       .type __cxa_end_cleanup, \"function\"\n"
 163 "__cxa_end_cleanup:\n"
 164 "       stw     .d2t2   B9, *B15--[10]\n"
 165 "       stw     .d2t2   B8, *+B15[9]\n"
 166 "       stw     .d2t2   B7, *+B15[8]\n"
 167 "       stw     .d2t2   B6, *+B15[7]\n"
 168 "       stw     .d2t2   B5, *+B15[6]\n"
 169 "       stw     .d2t2   B4, *+B15[5]\n"
 170 "       stw     .d2t1   A9, *+B15[4]\n"
 171 "       stw     .d2t1   A8, *+B15[3]\n"
 172 "       stw     .d2t1   A7, *+B15[2]\n"
 173 "       stw     .d2t1   A6, *+B15[1]\n"
 174 #ifdef _TMS320C6400_PLUS
 175 "       callp   .s2     (__gnu_end_cleanup), B3\n"
 176 #elif defined(_TMS320C6400)
 177 "       call    .s2     (__gnu_end_cleanup)\n"
 178 "       addkpc  .s2     1f, B3, 0\n"
 179 "       nop             4\n"
 180 "1:\n"
 181 #else
 182 "       call    .s2     (__gnu_end_cleanup)\n"
 183 "       mvkl    .s2     1f, B3\n"
 184 "       mvkh    .s2     1f, B3\n"
 185 "       nop             3\n"
 186 "1:\n"
 187 #endif
 188 "       ldw     .d2t1   *+B15[1], A6\n"
 189 "       ldw     .d2t1   *+B15[2], A7\n"
 190 "       ldw     .d2t1   *+B15[3], A8\n"
 191 "       ldw     .d2t1   *+B15[4], A9\n"
 192 "       ldw     .d2t2   *+B15[5], B4\n"
 193 "       ldw     .d2t2   *+B15[6], B5\n"
 194 "       ldw     .d2t2   *+B15[7], B6\n"
 195 "       ldw     .d2t2   *+B15[8], B7\n"
 196 "       ldw     .d2t2   *+B15[9], B8\n"
 197 "       ldw     .d2t2   *++B15[10], B9\n"
 198 "       b       .s2     _Unwind_Resume\n"
 199 "       nop             5\n");
 200 #else
 201 // Assembly wrapper to call __gnu_end_cleanup without clobbering r1-r3.
 202 // Also push r4 to preserve stack alignment.
 203 #ifdef __thumb__
 204 asm ("  .pushsection .text.__cxa_end_cleanup\n"
 205 "       .global __cxa_end_cleanup\n"
 206 "       .type __cxa_end_cleanup, \"function\"\n"
 207 "       .thumb_func\n"
 208 "__cxa_end_cleanup:\n"
 209 "       push\t{r1, r2, r3, r4}\n"
 210 "       bl\t__gnu_end_cleanup\n"
 211 "       pop\t{r1, r2, r3, r4}\n"
 212 "       bl\t_Unwind_Resume @ Never returns\n"
 213 "       .popsection\n");
 214 #else
 215 asm ("  .pushsection .text.__cxa_end_cleanup\n"
 216 "       .global __cxa_end_cleanup\n"
 217 "       .type __cxa_end_cleanup, \"function\"\n"
 218 "__cxa_end_cleanup:\n"
 219 "       stmfd\tsp!, {r1, r2, r3, r4}\n"
 220 "       bl\t__gnu_end_cleanup\n"
 221 "       ldmfd\tsp!, {r1, r2, r3, r4}\n"
 222 "       bl\t_Unwind_Resume @ Never returns\n"
 223 "       .popsection\n");
 224 #endif
 225 #endif
 226
 227 #endif