// GNU D Compiler exception personality routines. // Copyright (C) 2011-2022 Free Software Foundation, Inc. // GCC is free software; you can redistribute it and/or modify it under // the terms of the GNU General Public License as published by the Free // Software Foundation; either version 3, or (at your option) any later // version. // GCC is distributed in the hope that it will be useful, but WITHOUT ANY // WARRANTY; without even the implied warranty of MERCHANTABILITY or // FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License // for more details. // Under Section 7 of GPL version 3, you are granted additional // permissions described in the GCC Runtime Library Exception, version // 3.1, as published by the Free Software Foundation. // You should have received a copy of the GNU General Public License and // a copy of the GCC Runtime Library Exception along with this program; // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see // . // This code is based on the libstdc++ exception handling routines. module gcc.deh; import gcc.unwind; import gcc.unwind.pe; import gcc.builtins; import gcc.config; import gcc.attributes; extern(C) { int _d_isbaseof(ClassInfo, ClassInfo) @nogc nothrow pure @safe; void _d_createTrace(Throwable, void*); void _d_print_throwable(Throwable t); } /** * Declare all known and handled exception classes. * D exceptions -- "GNUCD\0\0\0". * C++ exceptions -- "GNUCC++\0" * C++ dependent exceptions -- "GNUCC++\x01" */ static if (GNU_ARM_EABI_Unwinder) { enum _Unwind_Exception_Class gdcExceptionClass = "GNUCD\0\0\0"; enum _Unwind_Exception_Class gxxExceptionClass = "GNUCC++\0"; enum _Unwind_Exception_Class gxxDependentExceptionClass = "GNUCC++\x01"; } else { enum _Unwind_Exception_Class gdcExceptionClass = (cast(_Unwind_Exception_Class)'G' << 56) | (cast(_Unwind_Exception_Class)'N' << 48) | (cast(_Unwind_Exception_Class)'U' << 40) | (cast(_Unwind_Exception_Class)'C' << 32) | (cast(_Unwind_Exception_Class)'D' << 24); enum _Unwind_Exception_Class gxxExceptionClass = (cast(_Unwind_Exception_Class)'G' << 56) | (cast(_Unwind_Exception_Class)'N' << 48) | (cast(_Unwind_Exception_Class)'U' << 40) | (cast(_Unwind_Exception_Class)'C' << 32) | (cast(_Unwind_Exception_Class)'C' << 24) | (cast(_Unwind_Exception_Class)'+' << 16) | (cast(_Unwind_Exception_Class)'+' << 8) | (cast(_Unwind_Exception_Class)0 << 0); enum _Unwind_Exception_Class gxxDependentExceptionClass = gxxExceptionClass + 1; } /** * Checks for GDC exception class. */ bool isGdcExceptionClass(_Unwind_Exception_Class c) @nogc { static if (GNU_ARM_EABI_Unwinder) { return c[0] == gdcExceptionClass[0] && c[1] == gdcExceptionClass[1] && c[2] == gdcExceptionClass[2] && c[3] == gdcExceptionClass[3] && c[4] == gdcExceptionClass[4] && c[5] == gdcExceptionClass[5] && c[6] == gdcExceptionClass[6] && c[7] == gdcExceptionClass[7]; } else { return c == gdcExceptionClass; } } /** * Checks for any C++ exception class. */ bool isGxxExceptionClass(_Unwind_Exception_Class c) @nogc { static if (GNU_ARM_EABI_Unwinder) { return c[0] == gxxExceptionClass[0] && c[1] == gxxExceptionClass[1] && c[2] == gxxExceptionClass[2] && c[3] == gxxExceptionClass[3] && c[4] == gxxExceptionClass[4] && c[5] == gxxExceptionClass[5] && c[6] == gxxExceptionClass[6] && (c[7] == gxxExceptionClass[7] || c[7] == gxxDependentExceptionClass[7]); } else { return c == gxxExceptionClass || c == gxxDependentExceptionClass; } } /** * Checks for primary or dependent, but not that it is a C++ exception. */ bool isDependentException(_Unwind_Exception_Class c) @nogc { static if (GNU_ARM_EABI_Unwinder) return (c[7] == '\x01'); else return (c & 1); } /** * A D exception object consists of a header, which is a wrapper * around an unwind object header with additional D specific * information, prefixed by the exception object itself. */ struct ExceptionHeader { // Because of a lack of __aligned__ style attribute, our object // and the unwind object are the first two fields. static if (Throwable.alignof < _Unwind_Exception.alignof) ubyte[_Unwind_Exception.alignof - Throwable.alignof] pad; // The object being thrown. The compiled code expects this to // be immediately before the generic exception header. Throwable object; // The generic exception header. _Unwind_Exception unwindHeader; static assert(unwindHeader.offsetof - object.offsetof == object.sizeof); // Cache handler details between Phase 1 and Phase 2. static if (GNU_ARM_EABI_Unwinder) { // Nothing here yet. } else { // Which catch was found. int handler; // Language Specific Data Area for function enclosing the handler. const(ubyte)* languageSpecificData; // Pointer to catch code. _Unwind_Ptr landingPad; // Canonical Frame Address (CFA) for the enclosing handler. _Unwind_Word canonicalFrameAddress; } // Stack other thrown exceptions in current thread through here. ExceptionHeader* next; // Thread local stack of chained exceptions. static ExceptionHeader* stack; // Pre-allocate storage for 1 instance per thread. // Use calloc/free for multiple exceptions in flight. static ExceptionHeader ehstorage; /** * Allocate and initialize an ExceptionHeader. */ static ExceptionHeader* create(Throwable o) @nogc { auto eh = &ehstorage; // Check exception object in use. if (eh.object) { eh = cast(ExceptionHeader*) __builtin_calloc(ExceptionHeader.sizeof, 1); // Out of memory while throwing - not much else can be done. if (!eh) terminate("out of memory", __LINE__); } eh.object = o; eh.unwindHeader.exception_class = gdcExceptionClass; return eh; } /** * Free ExceptionHeader that was created by create(). */ static void free(ExceptionHeader* eh) @nogc { __builtin_memset(eh, 0, ExceptionHeader.sizeof); if (eh != &ehstorage) __builtin_free(eh); } /** * Push this onto stack of chained exceptions. */ void push() @nogc { next = stack; stack = &this; } /** * Pop and return top of chained exception stack. */ static ExceptionHeader* pop() @nogc { auto eh = stack; stack = eh.next; return eh; } /** * Save stage1 handler information in the exception object. */ static void save(_Unwind_Exception* unwindHeader, _Unwind_Word cfa, int handler, const(ubyte)* lsda, _Unwind_Ptr landingPad) @nogc { static if (GNU_ARM_EABI_Unwinder) { unwindHeader.barrier_cache.sp = cfa; unwindHeader.barrier_cache.bitpattern[1] = cast(_uw)handler; unwindHeader.barrier_cache.bitpattern[2] = cast(_uw)lsda; unwindHeader.barrier_cache.bitpattern[3] = cast(_uw)landingPad; } else { ExceptionHeader* eh = toExceptionHeader(unwindHeader); eh.canonicalFrameAddress = cfa; eh.handler = handler; eh.languageSpecificData = lsda; eh.landingPad = landingPad; } } /** * Restore the catch handler data saved during phase1. */ static void restore(_Unwind_Exception* unwindHeader, out int handler, out const(ubyte)* lsda, out _Unwind_Ptr landingPad, out _Unwind_Word cfa) @nogc { static if (GNU_ARM_EABI_Unwinder) { cfa = unwindHeader.barrier_cache.sp; handler = cast(int)unwindHeader.barrier_cache.bitpattern[1]; lsda = cast(ubyte*)unwindHeader.barrier_cache.bitpattern[2]; landingPad = cast(_Unwind_Ptr)unwindHeader.barrier_cache.bitpattern[3]; } else { ExceptionHeader* eh = toExceptionHeader(unwindHeader); cfa = eh.canonicalFrameAddress; handler = eh.handler; lsda = eh.languageSpecificData; landingPad = cast(_Unwind_Ptr)eh.landingPad; } } /** * Convert from pointer to unwindHeader to pointer to ExceptionHeader * that it is embedded inside of. */ static ExceptionHeader* toExceptionHeader(_Unwind_Exception* exc) @nogc { return cast(ExceptionHeader*)(cast(void*)exc - ExceptionHeader.unwindHeader.offsetof); } } /** * Map to C++ std::type_info's virtual functions from D, * being careful to not require linking with libstdc++. * So it is given a different name. */ extern(C++) interface CxxTypeInfo { void dtor1(); void dtor2(); bool __is_pointer_p() const; bool __is_function_p() const; bool __do_catch(const CxxTypeInfo, void**, uint) const; bool __do_upcast(const void*, void**) const; } /** * Structure of a C++ exception, represented as a C structure. * See unwind-cxx.h for the full definition. */ struct CxaExceptionHeader { union { CxxTypeInfo exceptionType; void* primaryException; } void function(void*) exceptionDestructor; void function() unexpectedHandler; void function() terminateHandler; CxaExceptionHeader* nextException; int handlerCount; static if (GNU_ARM_EABI_Unwinder) { CxaExceptionHeader* nextPropagatingException; int propagationCount; } else { int handlerSwitchValue; const(ubyte)* actionRecord; const(ubyte)* languageSpecificData; _Unwind_Ptr catchTemp; void* adjustedPtr; } _Unwind_Exception unwindHeader; /** * There's no saving between phases, so only cache pointer. * __cxa_begin_catch expects this to be set. */ static void save(_Unwind_Exception* unwindHeader, void* thrownPtr) @nogc { static if (GNU_ARM_EABI_Unwinder) unwindHeader.barrier_cache.bitpattern[0] = cast(_uw) thrownPtr; else { auto eh = toExceptionHeader(unwindHeader); eh.adjustedPtr = thrownPtr; } } /** * Get pointer to the thrown object if the thrown object type behind the * exception is implicitly convertible to the catch type. */ static void* getAdjustedPtr(_Unwind_Exception* exc, CxxTypeInfo catchType) { void* thrownPtr; // A dependent C++ exceptions is just a wrapper around the unwind header. // A primary C++ exception has the thrown object located immediately after it. if (isDependentException(exc.exception_class)) thrownPtr = toExceptionHeader(exc).primaryException; else thrownPtr = cast(void*)(exc + 1); // Pointer types need to adjust the actual pointer, not the pointer that is // the exception object. This also has the effect of passing pointer types // "by value" through the __cxa_begin_catch return value. const throw_type = (cast(CxaExceptionHeader*)thrownPtr - 1).exceptionType; if (throw_type.__is_pointer_p()) thrownPtr = *cast(void**)thrownPtr; // Pointer adjustment may be necessary due to multiple inheritance if (catchType is throw_type || catchType.__do_catch(throw_type, &thrownPtr, 1)) return thrownPtr; return null; } /** * Convert from pointer to unwindHeader to pointer to CxaExceptionHeader * that it is embedded inside of. */ static CxaExceptionHeader* toExceptionHeader(_Unwind_Exception* exc) @nogc { return cast(CxaExceptionHeader*)(exc + 1) - 1; } } /** * Called if exception handling must be abandoned for any reason. */ private void terminate(string msg, uint line) @nogc { import core.stdc.stdio; import core.stdc.stdlib; static bool terminating; if (terminating) { fputs("terminate called recursively\n", stderr); abort(); } terminating = true; fprintf(stderr, "gcc.deh(%u): %.*s\n", line, cast(int)msg.length, msg.ptr); abort(); } /** * Called when fibers switch contexts. */ extern(C) void* _d_eh_swapContext(void* newContext) nothrow @nogc { auto old = ExceptionHeader.stack; ExceptionHeader.stack = cast(ExceptionHeader*)newContext; return old; } /** * Called before starting a catch. Returns the exception object. */ extern(C) void* __gdc_begin_catch(_Unwind_Exception* unwindHeader) { ExceptionHeader* header = ExceptionHeader.toExceptionHeader(unwindHeader); void* objectp = cast(void*)header.object; // Remove our reference to the exception. We should not decrease its refcount, // because we pass the object on to the caller. header.object = null; // Something went wrong when stacking up chained headers... if (header != ExceptionHeader.pop()) terminate("catch error", __LINE__); // Handling for this exception is complete. _Unwind_DeleteException(&header.unwindHeader); return objectp; } /** * Perform a throw, D style. Throw will unwind through this call, * so there better not be any handlers or exception thrown here. */ extern(C) void _d_throw(Throwable object) { // If possible, avoid always allocating new memory for exception headers. ExceptionHeader *eh = ExceptionHeader.create(object); // Add to thrown exception stack. eh.push(); // Increment reference count if object is a refcounted Throwable. auto refcount = object.refcount(); if (refcount) object.refcount() = refcount + 1; // Called by unwinder when exception object needs destruction by other than our code. extern(C) void exception_cleanup(_Unwind_Reason_Code code, _Unwind_Exception* exc) { // If we haven't been caught by a foreign handler, then this is // some sort of unwind error. In that case just die immediately. // _Unwind_DeleteException in the HP-UX IA64 libunwind library // returns _URC_NO_REASON and not _URC_FOREIGN_EXCEPTION_CAUGHT // like the GCC _Unwind_DeleteException function does. if (code != _URC_FOREIGN_EXCEPTION_CAUGHT && code != _URC_NO_REASON) terminate("uncaught exception", __LINE__); auto eh = ExceptionHeader.toExceptionHeader(exc); ExceptionHeader.free(eh); } eh.unwindHeader.exception_cleanup = &exception_cleanup; // Runtime now expects us to do this first before unwinding. _d_createTrace(eh.object, null); // We're happy with setjmp/longjmp exceptions or region-based // exception handlers: entry points are provided here for both. _Unwind_Reason_Code r = void; version (GNU_SjLj_Exceptions) r = _Unwind_SjLj_RaiseException(&eh.unwindHeader); else r = _Unwind_RaiseException(&eh.unwindHeader); // If code == _URC_END_OF_STACK, then we reached top of stack without finding // a handler for the exception. Since each thread is run in a try/catch, // this oughtn't happen. If code is something else, we encountered some sort // of heinous lossage from which we could not recover. As is the way of such // things, almost certainly we will have crashed before now, rather than // actually being able to diagnose the problem. if (r == _URC_END_OF_STACK) { __gdc_begin_catch(&eh.unwindHeader); _d_print_throwable(object); terminate("uncaught exception", __LINE__); } terminate("unwind error", __LINE__); } static if (GNU_ARM_EABI_Unwinder) { enum personality_fn_attributes = attribute("target", ("general-regs-only")); } else { enum personality_fn_attributes = ""; } /** * Read and extract information from the LSDA (.gcc_except_table section). */ @personality_fn_attributes _Unwind_Reason_Code scanLSDA(const(ubyte)* lsda, _Unwind_Exception_Class exceptionClass, _Unwind_Action actions, _Unwind_Exception* unwindHeader, _Unwind_Context* context, _Unwind_Word cfa, out _Unwind_Ptr landingPad, out int handler) { // If no LSDA, then there are no handlers or cleanups. if (lsda is null) return CONTINUE_UNWINDING(unwindHeader, context); // Parse the LSDA header auto p = lsda; auto Start = (context ? _Unwind_GetRegionStart(context) : 0); // Find @LPStart, the base to which landing pad offsets are relative. ubyte LPStartEncoding = *p++; _Unwind_Ptr LPStart = 0; if (LPStartEncoding != DW_EH_PE_omit) LPStart = read_encoded_value(context, LPStartEncoding, p); else LPStart = Start; // Find @TType, the base of the handler and exception spec type data. ubyte TTypeEncoding = *p++; const(ubyte)* TType = null; if (TTypeEncoding != DW_EH_PE_omit) { static if (__traits(compiles, _TTYPE_ENCODING)) { // Older ARM EABI toolchains set this value incorrectly, so use a // hardcoded OS-specific format. TTypeEncoding = _TTYPE_ENCODING; } auto TTbase = read_uleb128(p); TType = p + TTbase; } // The encoding and length of the call-site table; the action table // immediately follows. ubyte CSEncoding = *p++; auto CSTableSize = read_uleb128(p); const(ubyte)* actionTable = p + CSTableSize; auto TTypeBase = base_of_encoded_value(TTypeEncoding, context); // Get instruction pointer (ip) at start of instruction that threw. version (CRuntime_Glibc) { int ip_before_insn; auto ip = _Unwind_GetIPInfo(context, &ip_before_insn); if (!ip_before_insn) --ip; } else { auto ip = _Unwind_GetIP(context); --ip; } bool saw_cleanup = false; bool saw_handler = false; const(ubyte)* actionRecord = null; version (GNU_SjLj_Exceptions) { // The given "IP" is an index into the call-site table, with two // exceptions -- -1 means no-action, and 0 means terminate. // But since we're using uleb128 values, we've not got random // access to the array. if (cast(int) ip <= 0) { return _URC_CONTINUE_UNWIND; } else { _uleb128_t CSLandingPad, CSAction; do { CSLandingPad = read_uleb128(p); CSAction = read_uleb128(p); } while (--ip); // Can never have null landing pad for sjlj -- that would have // been indicated by a -1 call site index. landingPad = CSLandingPad + 1; if (CSAction) actionRecord = actionTable + CSAction - 1; } } else { // Search the call-site table for the action associated with this IP. while (p < actionTable) { // Note that all call-site encodings are "absolute" displacements. auto CSStart = read_encoded_value(null, CSEncoding, p); auto CSLen = read_encoded_value(null, CSEncoding, p); auto CSLandingPad = read_encoded_value(null, CSEncoding, p); auto CSAction = read_uleb128(p); // The table is sorted, so if we've passed the ip, stop. if (ip < Start + CSStart) p = actionTable; else if (ip < Start + CSStart + CSLen) { if (CSLandingPad) landingPad = LPStart + CSLandingPad; if (CSAction) actionRecord = actionTable + CSAction - 1; break; } } } if (landingPad == 0) { // IP is present, but has a null landing pad. // No cleanups or handlers to be run. } else if (actionRecord is null) { // If ip is present, has a non-null landing pad, and a null // action table offset, then there are only cleanups present. // Cleanups use a zero switch value, as set above. saw_cleanup = true; } else { // Otherwise we have a catch handler or exception specification. handler = actionTableLookup(actions, unwindHeader, actionRecord, lsda, exceptionClass, TTypeBase, TType, TTypeEncoding, saw_handler, saw_cleanup); } // IP is not in table. No associated cleanups. if (!saw_handler && !saw_cleanup) return CONTINUE_UNWINDING(unwindHeader, context); if (actions & _UA_SEARCH_PHASE) { if (!saw_handler) return CONTINUE_UNWINDING(unwindHeader, context); // For domestic exceptions, we cache data from phase 1 for phase 2. if (isGdcExceptionClass(exceptionClass)) ExceptionHeader.save(unwindHeader, cfa, handler, lsda, landingPad); return _URC_HANDLER_FOUND; } return 0; } /** * Look up and return the handler index of the classType in Action Table. */ int actionTableLookup(_Unwind_Action actions, _Unwind_Exception* unwindHeader, const(ubyte)* actionRecord, const(ubyte)* lsda, _Unwind_Exception_Class exceptionClass, _Unwind_Ptr TTypeBase, const(ubyte)* TType, ubyte TTypeEncoding, out bool saw_handler, out bool saw_cleanup) { ClassInfo thrownType; if (isGdcExceptionClass(exceptionClass)) { thrownType = getClassInfo(unwindHeader, lsda); } while (1) { auto ap = actionRecord; auto ARFilter = read_sleb128(ap); auto apn = ap; auto ARDisp = read_sleb128(ap); if (ARFilter == 0) { // Zero filter values are cleanups. saw_cleanup = true; } else if (actions & _UA_FORCE_UNWIND) { // During forced unwinding, we only run cleanups. } else if (ARFilter > 0) { // Positive filter values are handlers. auto encodedSize = size_of_encoded_value(TTypeEncoding); // ARFilter is the negative index from TType, which is where // the ClassInfo is stored. const(ubyte)* tp = TType - ARFilter * encodedSize; auto entry = read_encoded_value_with_base(TTypeEncoding, TTypeBase, tp); ClassInfo ci = cast(ClassInfo)cast(void*)(entry); // D does not have catch-all handlers, and so the following // assumes that we will never handle a null value. assert(ci !is null); if (ci.classinfo is __cpp_type_info_ptr.classinfo && isGxxExceptionClass(exceptionClass)) { // catchType is the catch clause type_info. auto catchType = cast(CxxTypeInfo)((cast(__cpp_type_info_ptr)cast(void*)ci).ptr); auto thrownPtr = CxaExceptionHeader.getAdjustedPtr(unwindHeader, catchType); if (thrownPtr !is null) { if (actions & _UA_SEARCH_PHASE) CxaExceptionHeader.save(unwindHeader, thrownPtr); saw_handler = true; return cast(int)ARFilter; } } else if (isGdcExceptionClass(exceptionClass) && _d_isbaseof(thrownType, ci)) { saw_handler = true; return cast(int)ARFilter; } else { // ??? What to do about other GNU language exceptions. } } else { // Negative filter values are exception specifications, // which D does not use. break; } if (ARDisp == 0) break; actionRecord = apn + ARDisp; } return 0; } /** * Look at the chain of inflight exceptions and pick the class type that'll * be looked for in catch clauses. */ ClassInfo getClassInfo(_Unwind_Exception* unwindHeader, const(ubyte)* currentLsd) @nogc { ExceptionHeader* eh = ExceptionHeader.toExceptionHeader(unwindHeader); // The first thrown Exception at the top of the stack takes precedence // over others that are inflight, unless an Error was thrown, in which // case, we search for error handlers instead. Throwable ehobject = eh.object; for (ExceptionHeader* ehn = eh.next; ehn; ehn = ehn.next) { const(ubyte)* nextLsd = void; _Unwind_Ptr nextLandingPad = void; _Unwind_Word nextCfa = void; int nextHandler = void; ExceptionHeader.restore(&ehn.unwindHeader, nextHandler, nextLsd, nextLandingPad, nextCfa); // Don't combine when the exceptions are from different functions. if (currentLsd != nextLsd) break; Error e = cast(Error)ehobject; if (e is null || (cast(Error)ehn.object) !is null) { currentLsd = nextLsd; ehobject = ehn.object; } } return ehobject.classinfo; } /** * Called when the personality function has found neither a cleanup or handler. * To support ARM EABI personality routines, that must also unwind the stack. */ @personality_fn_attributes _Unwind_Reason_Code CONTINUE_UNWINDING(_Unwind_Exception* unwindHeader, _Unwind_Context* context) { static if (GNU_ARM_EABI_Unwinder) { if (__gnu_unwind_frame(unwindHeader, context) != _URC_OK) return _URC_FAILURE; } return _URC_CONTINUE_UNWIND; } /** * Using a different personality function name causes link failures * when trying to mix code using different exception handling models. */ version (GNU_SEH_Exceptions) { enum PERSONALITY_FUNCTION = "__gdc_personality_imp"; extern(C) EXCEPTION_DISPOSITION __gdc_personality_seh0(void* ms_exc, void* this_frame, void* ms_orig_context, void* ms_disp) { return _GCC_specific_handler(ms_exc, this_frame, ms_orig_context, ms_disp, &gdc_personality); } } else version (GNU_SjLj_Exceptions) { enum PERSONALITY_FUNCTION = "__gdc_personality_sj0"; private int __builtin_eh_return_data_regno(int x) { return x; } } else { enum PERSONALITY_FUNCTION = "__gdc_personality_v0"; } /** * The "personality" function, specific to each language. */ static if (GNU_ARM_EABI_Unwinder) { pragma(mangle, PERSONALITY_FUNCTION) @personality_fn_attributes extern(C) _Unwind_Reason_Code gdc_personality(_Unwind_State state, _Unwind_Exception* unwindHeader, _Unwind_Context* context) { _Unwind_Action actions; switch (state & _US_ACTION_MASK) { case _US_VIRTUAL_UNWIND_FRAME: // If the unwind state pattern is (_US_VIRTUAL_UNWIND_FRAME | _US_FORCE_UNWIND) // then we don't need to search for any handler as it is not a real exception. // Just unwind the stack. if (state & _US_FORCE_UNWIND) return CONTINUE_UNWINDING(unwindHeader, context); actions = _UA_SEARCH_PHASE; break; case _US_UNWIND_FRAME_STARTING: actions = _UA_CLEANUP_PHASE; if (!(state & _US_FORCE_UNWIND) && unwindHeader.barrier_cache.sp == _Unwind_GetGR(context, UNWIND_STACK_REG)) actions |= _UA_HANDLER_FRAME; break; case _US_UNWIND_FRAME_RESUME: return CONTINUE_UNWINDING(unwindHeader, context); default: terminate("unwind error", __LINE__); } actions |= state & _US_FORCE_UNWIND; // The dwarf unwinder assumes the context structure holds things like // the function and LSDA pointers. The ARM implementation caches these // in the exception header (UCB). To avoid rewriting everything we make // the virtual IP register point at the UCB. _Unwind_SetGR(context, UNWIND_POINTER_REG, cast(_Unwind_Ptr)unwindHeader); return __gdc_personality(actions, unwindHeader.exception_class, unwindHeader, context); } } else { pragma(mangle, PERSONALITY_FUNCTION) extern(C) _Unwind_Reason_Code gdc_personality(int iversion, _Unwind_Action actions, _Unwind_Exception_Class exceptionClass, _Unwind_Exception* unwindHeader, _Unwind_Context* context) { // Interface version check. if (iversion != 1) return _URC_FATAL_PHASE1_ERROR; return __gdc_personality(actions, exceptionClass, unwindHeader, context); } } @personality_fn_attributes private _Unwind_Reason_Code __gdc_personality(_Unwind_Action actions, _Unwind_Exception_Class exceptionClass, _Unwind_Exception* unwindHeader, _Unwind_Context* context) { const(ubyte)* lsda; _Unwind_Ptr landingPad; _Unwind_Word cfa; int handler; // Shortcut for phase 2 found handler for domestic exception. if (actions == (_UA_CLEANUP_PHASE | _UA_HANDLER_FRAME) && isGdcExceptionClass(exceptionClass)) { ExceptionHeader.restore(unwindHeader, handler, lsda, landingPad, cfa); // Shouldn't have cached a null landing pad in phase 1. if (landingPad == 0) terminate("unwind error", __LINE__); } else { lsda = cast(ubyte*)_Unwind_GetLanguageSpecificData(context); static if (GNU_ARM_EABI_Unwinder) cfa = _Unwind_GetGR(context, UNWIND_STACK_REG); else cfa = _Unwind_GetCFA(context); auto result = scanLSDA(lsda, exceptionClass, actions, unwindHeader, context, cfa, landingPad, handler); // Positive on handler found in phase 1, continue unwinding, or failure. if (result) return result; } // Unexpected negative handler, call terminate directly. if (handler < 0) terminate("unwind error", __LINE__); // We can't use any of the deh routines with foreign exceptions, // because they all expect unwindHeader to be an ExceptionHeader. if (isGdcExceptionClass(exceptionClass)) { // If there are any in-flight exceptions being thrown, chain our // current object onto the end of the prevous object. ExceptionHeader* eh = ExceptionHeader.toExceptionHeader(unwindHeader); auto currentLsd = lsda; bool bypassed = false; while (eh.next) { ExceptionHeader* ehn = eh.next; const(ubyte)* nextLsd = void; _Unwind_Ptr nextLandingPad = void; _Unwind_Word nextCfa = void; int nextHandler = void; ExceptionHeader.restore(&ehn.unwindHeader, nextHandler, nextLsd, nextLandingPad, nextCfa); Error e = cast(Error)eh.object; if (e !is null && !cast(Error)ehn.object) { // We found an Error, bypass the exception chain. currentLsd = nextLsd; eh = ehn; bypassed = true; continue; } // Don't combine when the exceptions are from different functions. if (currentLsd != nextLsd) break; // Add our object onto the end of the existing chain and replace // our exception object with in-flight one. eh.object = Throwable.chainTogether(ehn.object, eh.object); if (nextHandler != handler && !bypassed) { handler = nextHandler; ExceptionHeader.save(unwindHeader, cfa, handler, lsda, landingPad); } // Exceptions chained, can now throw away the previous header. eh.next = ehn.next; _Unwind_DeleteException(&ehn.unwindHeader); } if (bypassed) { eh = ExceptionHeader.toExceptionHeader(unwindHeader); Error e = cast(Error)eh.object; auto ehn = eh.next; e.bypassedException = ehn.object; eh.next = ehn.next; _Unwind_DeleteException(&ehn.unwindHeader); } } // Set up registers and jump to cleanup or handler. // For targets with pointers smaller than the word size, we must extend the // pointer, and this extension is target dependent. _Unwind_SetGR(context, __builtin_eh_return_data_regno(0), cast(_Unwind_Ptr)unwindHeader); _Unwind_SetGR(context, __builtin_eh_return_data_regno(1), handler); _Unwind_SetIP(context, landingPad); return _URC_INSTALL_CONTEXT; }