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 179