Index: libcfa/src/exception.c =================================================================== --- libcfa/src/exception.c (revision 2a3b019aa0163c7f5574a142e8a058af99a7fa71) +++ libcfa/src/exception.c (revision 9cb89b8729329516d0bdd5fc3576f17ad688fcd5) @@ -58,10 +58,10 @@ exception_t * current_exception; int current_handler_index; -} shared_stack = {NULL, NULL, 0, 0}; +} static shared_stack = {NULL, NULL, NULL, 0}; // Get the current exception context. // There can be a single global until multithreading occurs, then each stack // needs its own. It will have to be updated to handle that. -inline static struct exception_context_t * this_exception_context() { +struct exception_context_t * this_exception_context() { return &shared_stack; } @@ -162,5 +162,5 @@ node = EXCEPT_TO_NODE(context->current_exception); // It may always be in the first or second position. - while( to_free != node->next ) { + while ( to_free != node->next ) { node = node->next; } @@ -191,6 +191,6 @@ struct _Unwind_Context * unwind_context, void * stop_param) { - if( actions & _UA_END_OF_STACK ) exit(1); - if( actions & _UA_CLEANUP_PHASE ) return _URC_NO_REASON; + if ( actions & _UA_END_OF_STACK ) exit(1); + if ( actions & _UA_CLEANUP_PHASE ) return _URC_NO_REASON; return _URC_FATAL_PHASE2_ERROR; @@ -215,5 +215,5 @@ // the whole stack. - if( ret == _URC_END_OF_STACK ) { + if ( ret == _URC_END_OF_STACK ) { // No proper handler was found. This can be handled in many ways, C++ calls std::terminate. // Here we force unwind the stack, basically raising a cancellation. @@ -257,5 +257,5 @@ // If we've reached the end of the stack then there is nothing much we can do... - if( actions & _UA_END_OF_STACK ) return _URC_END_OF_STACK; + if (actions & _UA_END_OF_STACK) return _URC_END_OF_STACK; if (actions & _UA_SEARCH_PHASE) { @@ -272,7 +272,7 @@ // Get a pointer to the language specific data from which we will read what we need - const unsigned char * lsd = (const unsigned char*) _Unwind_GetLanguageSpecificData( unwind_context ); - - if( !lsd ) { //Nothing to do, keep unwinding + const unsigned char * lsd = _Unwind_GetLanguageSpecificData( unwind_context ); + + if ( !lsd ) { //Nothing to do, keep unwinding printf(" no LSD"); goto UNWIND; @@ -287,5 +287,5 @@ // Linearly search the table for stuff to do - while( cur_ptr < lsd_info.action_table ) { + while ( cur_ptr < lsd_info.action_table ) { _Unwind_Ptr callsite_start; _Unwind_Ptr callsite_len; @@ -300,5 +300,5 @@ // Have we reach the correct frame info yet? - if( lsd_info.Start + callsite_start + callsite_len < instruction_ptr ) { + if ( lsd_info.Start + callsite_start + callsite_len < instruction_ptr ) { #ifdef __CFA_DEBUG_PRINT__ void * ls = (void*)lsd_info.Start; @@ -315,87 +315,85 @@ // Have we gone too far? - if( lsd_info.Start + callsite_start > instruction_ptr ) { + if ( lsd_info.Start + callsite_start > instruction_ptr ) { printf(" gone too far"); break; } - // Something to do? + // Check for what we must do: if ( 0 == callsite_landing_pad ) { // Nothing to do, move along __cfaabi_dbg_print_safe(" no landing pad"); - } else { - // Which phase are we in - if (actions & _UA_SEARCH_PHASE) { - // In search phase, these means we found a potential handler we must check. - - // We have arbitrarily decided that 0 means nothing to do and 1 means there is - // a potential handler. This doesn't seem to conflict the gcc default behavior. - if (callsite_action != 0) { - // Now we want to run some code to see if the handler matches - // This is the tricky part where we want to the power to run arbitrary code - // However, generating a new exception table entry and try routine every time - // is way more expansive than we might like - // The information we have is : - // - The GR (Series of registers) - // GR1=GP Global Pointer of frame ref by context - // - The instruction pointer - // - The instruction pointer info (???) - // - The CFA (Canonical Frame Address) - // - The BSP (Probably the base stack pointer) - - - // The current apprach uses one exception table entry per try block - _uleb128_t imatcher; - // Get the relative offset to the {...}? - cur_ptr = read_uleb128(cur_ptr, &imatcher); - -# if defined( __x86_64 ) - _Unwind_Word match_pos = _Unwind_GetCFA(unwind_context) + 8; -# elif defined( __i386 ) - _Unwind_Word match_pos = _Unwind_GetCFA(unwind_context) + 24; -# endif - int (*matcher)(exception_t *) = *(int(**)(exception_t *))match_pos; - - int index = matcher(context->current_exception); - _Unwind_Reason_Code ret = (0 == index) - ? _URC_CONTINUE_UNWIND : _URC_HANDLER_FOUND; - context->current_handler_index = index; - - // Based on the return value, check if we matched the exception - if( ret == _URC_HANDLER_FOUND) { - __cfaabi_dbg_print_safe(" handler found\n"); - } else { - __cfaabi_dbg_print_safe(" no handler\n"); - } - return ret; + } else if (actions & _UA_SEARCH_PHASE) { + // In search phase, these means we found a potential handler we must check. + + // We have arbitrarily decided that 0 means nothing to do and 1 means there is + // a potential handler. This doesn't seem to conflict the gcc default behavior. + if (callsite_action != 0) { + // Now we want to run some code to see if the handler matches + // This is the tricky part where we want to the power to run arbitrary code + // However, generating a new exception table entry and try routine every time + // is way more expansive than we might like + // The information we have is : + // - The GR (Series of registers) + // GR1=GP Global Pointer of frame ref by context + // - The instruction pointer + // - The instruction pointer info (???) + // - The CFA (Canonical Frame Address) + // - The BSP (Probably the base stack pointer) + + + // The current apprach uses one exception table entry per try block + _uleb128_t imatcher; + // Get the relative offset to the {...}? + cur_ptr = read_uleb128(cur_ptr, &imatcher); + +# if defined( __x86_64 ) + _Unwind_Word match_pos = _Unwind_GetCFA(unwind_context) + 8; +# elif defined( __i386 ) + _Unwind_Word match_pos = _Unwind_GetCFA(unwind_context) + 24; +# endif + int (*matcher)(exception_t *) = *(int(**)(exception_t *))match_pos; + + int index = matcher(context->current_exception); + _Unwind_Reason_Code ret = (0 == index) + ? _URC_CONTINUE_UNWIND : _URC_HANDLER_FOUND; + context->current_handler_index = index; + + // Based on the return value, check if we matched the exception + if (ret == _URC_HANDLER_FOUND) { + __cfaabi_dbg_print_safe(" handler found\n"); + } else { + __cfaabi_dbg_print_safe(" no handler\n"); } - - // This is only a cleanup handler, ignore it - __cfaabi_dbg_print_safe(" no action"); + return ret; } - else if (actions & _UA_CLEANUP_PHASE) { - - if( (callsite_action != 0) && !(actions & _UA_HANDLER_FRAME) ){ - // If this is a potential exception handler - // but not the one that matched the exception in the seach phase, - // just ignore it - goto UNWIND; - } - - // We need to run some clean-up or a handler - // These statment do the right thing but I don't know any specifics at all - _Unwind_SetGR( unwind_context, __builtin_eh_return_data_regno(0), - (_Unwind_Ptr)unwind_exception ); - _Unwind_SetGR( unwind_context, __builtin_eh_return_data_regno(1), 0 ); - - // I assume this sets the instruction pointer to the adress of the landing pad - // It doesn't actually set it, it only state the value that needs to be set once we return _URC_INSTALL_CONTEXT - _Unwind_SetIP( unwind_context, ((lsd_info.LPStart) + (callsite_landing_pad)) ); - - __cfaabi_dbg_print_safe(" action\n"); - - // Return have some action to run - return _URC_INSTALL_CONTEXT; + + // This is only a cleanup handler, ignore it + __cfaabi_dbg_print_safe(" no action"); + } else if (actions & _UA_CLEANUP_PHASE) { + // In clean-up phase, no destructors here but this could be the handler. + + if ( (callsite_action != 0) && !(actions & _UA_HANDLER_FRAME) ){ + // If this is a potential exception handler + // but not the one that matched the exception in the seach phase, + // just ignore it + goto UNWIND; } + + // We need to run some clean-up or a handler + // These statment do the right thing but I don't know any specifics at all + _Unwind_SetGR( unwind_context, __builtin_eh_return_data_regno(0), + (_Unwind_Ptr)unwind_exception ); + _Unwind_SetGR( unwind_context, __builtin_eh_return_data_regno(1), 0 ); + + // I assume this sets the instruction pointer to the adress of the landing pad + // It doesn't actually set it, it only state the value that needs to be set once we + // return _URC_INSTALL_CONTEXT + _Unwind_SetIP( unwind_context, ((lsd_info.LPStart) + (callsite_landing_pad)) ); + + __cfaabi_dbg_print_safe(" action\n"); + + // Return have some action to run + return _URC_INSTALL_CONTEXT; } } @@ -422,10 +420,8 @@ //! printf("%p %p %p %p\n", &try_block, &catch_block, &match_block, &xy); - // Setup statments: These 2 statments won't actually result in any code, they only setup global tables. - // However, they clobber gcc cancellation support from gcc. We can replace the personality routine but - // replacing the exception table gcc generates is not really doable, it generates labels based on how the - // assembly works. - // Setup the personality routine and exception table. + // Unforturnately these clobber gcc cancellation support which means we can't get access to + // the attribute cleanup tables at the same time. We would have to inspect the assembly to + // create a new set ourselves. #ifdef __PIC__ asm volatile (".cfi_personality 0x9b,CFA.ref.__gcfa_personality_v0"); @@ -452,7 +448,7 @@ // Label which defines the end of the area for which the handler is setup. asm volatile (".TRYEND:"); - // Label which defines the start of the exception landing pad. Basically what is called when the exception is - // caught. Note, if multiple handlers are given, the multiplexing should be done by the generated code, not the - // exception runtime. + // Label which defines the start of the exception landing pad. Basically what is called when + // the exception is caught. Note, if multiple handlers are given, the multiplexing should be + // done by the generated code, not the exception runtime. asm volatile (".CATCH:");