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" 96 #ifdef __ARM_EABI_UNWINDER__ 97 void 98 #else 99 bool 100 #endif 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 #ifndef __ARM_EABI_UNWINDER__ 130 return true; 131 #endif 132 } 133 134 // Do the work for __cxa_end_cleanup. Returns the currently propagating 135 // exception object. 136 extern "C" _Unwind_Exception * 137 __gnu_end_cleanup(void) 138 { 139 __cxa_exception *header; 140 __cxa_eh_globals *globals = __cxa_get_globals(); 141 142 header = globals->propagatingExceptions; 143 144 // Check something hasn't gone horribly wrong. 145 if (!header) 146 std::terminate(); 147 148 if (__is_gxx_exception_class(header->unwindHeader.exception_class)) 149 { 150 header->propagationCount--; 151 if (header->propagationCount == 0) 152 { 153 // Remove exception from chain. 154 globals->propagatingExceptions = header->nextPropagatingException; 155 header->nextPropagatingException = NULL; 156 } 157 } 158 else 159 globals->propagatingExceptions = NULL; 160 161 return &header->unwindHeader; 162 } 163 164 // Assembly wrapper to call __gnu_end_cleanup without clobbering r1-r3. 165 // Also push r4 to preserve stack alignment. 166 #ifdef __thumb__ 167 asm (".global __cxa_end_cleanup\n" 168 " .type __cxa_end_cleanup, \"function\"\n" 169 " .thumb_func\n" 170 "__cxa_end_cleanup:\n" 171 " push\t{r1, r2, r3, r4}\n" 172 " bl\t__gnu_end_cleanup\n" 173 " pop\t{r1, r2, r3, r4}\n" 174 " bl\t_Unwind_Resume @ Never returns\n"); 175 #else 176 asm (".global __cxa_end_cleanup\n" 177 " .type __cxa_end_cleanup, \"function\"\n" 178 "__cxa_end_cleanup:\n" 179 " stmfd\tsp!, {r1, r2, r3, r4}\n" 180 " bl\t__gnu_end_cleanup\n" 181 " ldmfd\tsp!, {r1, r2, r3, r4}\n" 182 " bl\t_Unwind_Resume @ Never returns\n"); 183 #endif 184 185 #endif 186