// GNU D Compiler exception personality routines.
// Copyright (C) 2011-2020 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
// <http://www.gnu.org/licenses/>.
// 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.attribute;
extern(C)
{
int _d_isbaseof(ClassInfo, ClassInfo);
void _d_createTrace(Object, void*);
// Not used in GDC but declaration required by rt/sections.d
struct FuncTable
{
}
}
/**
* 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
{
*eh = ExceptionHeader.init;
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;
}
}
/**
* Look at the chain of inflight exceptions and pick the class type that'll
* be looked for in catch clauses.
*/
static ClassInfo getClassInfo(_Unwind_Exception* unwindHeader) @nogc
{
ExceptionHeader* eh = 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)
{
Error e = cast(Error)ehobject;
if (e is null || (cast(Error)ehn.object) !is null)
ehobject = ehn.object;
}
return ehobject.classinfo;
}
/**
* 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;
// 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();
// 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)
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,
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, _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 = ExceptionHeader.getClassInfo(unwindHeader);
}
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;
}
/**
* 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_imp);
}
}
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;
auto currentCfa = cfa;
bool bypassed = false;
while (eh.next)
{
ExceptionHeader* ehn = eh.next;
const(ubyte)* nextLsd;
_Unwind_Ptr nextLandingPad;
_Unwind_Word nextCfa;
int nextHandler;
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;
currentCfa = nextCfa;
eh = ehn;
bypassed = true;
continue;
}
// Don't combine when the exceptions are from different functions.
if (currentLsd != nextLsd && currentCfa != nextCfa)
break;
// Add our object onto the end of the existing chain.
Throwable n = ehn.object;
while (n.next)
n = n.next;
n.next = eh.object;
// Replace our exception object with in-flight one
eh.object = ehn.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;
}