// -*- C++ -*- The GNU C++ exception personality routine.
// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
// 2011
// Free Software Foundation, Inc.
//
// This file is part of GCC.
//
// 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/>.
#include <bits/c++config.h>
#include <cstdlib>
#include <bits/exception_defines.h>
#include <cxxabi.h>
#include "unwind-cxx.h"
using namespace __cxxabiv1;
#include "unwind-pe.h"
struct lsda_header_info
{
_Unwind_Ptr Start;
_Unwind_Ptr LPStart;
_Unwind_Ptr ttype_base;
const unsigned char *TType;
const unsigned char *action_table;
unsigned char ttype_encoding;
unsigned char call_site_encoding;
};
static const unsigned char *
parse_lsda_header (_Unwind_Context *context, const unsigned char *p,
lsda_header_info *info)
{
_uleb128_t tmp;
unsigned char lpstart_encoding;
info->Start = (context ? _Unwind_GetRegionStart (context) : 0);
// Find @LPStart, the base to which landing pad offsets are relative.
lpstart_encoding = *p++;
if (lpstart_encoding != DW_EH_PE_omit)
p = read_encoded_value (context, lpstart_encoding, p, &info->LPStart);
else
info->LPStart = info->Start;
// Find @TType, the base of the handler and exception spec type data.
info->ttype_encoding = *p++;
if (info->ttype_encoding != DW_EH_PE_omit)
{
#if _GLIBCXX_OVERRIDE_TTYPE_ENCODING
/* Older ARM EABI toolchains set this value incorrectly, so use a
hardcoded OS-specific format. */
info->ttype_encoding = _GLIBCXX_OVERRIDE_TTYPE_ENCODING;
#endif
p = read_uleb128 (p, &tmp);
info->TType = p + tmp;
}
else
info->TType = 0;
// The encoding and length of the call-site table; the action table
// immediately follows.
info->call_site_encoding = *p++;
p = read_uleb128 (p, &tmp);
info->action_table = p + tmp;
return p;
}
// Return an element from a type table.
static const std::type_info*
get_ttype_entry(lsda_header_info* info, _uleb128_t i)
{
_Unwind_Ptr ptr;
i *= size_of_encoded_value (info->ttype_encoding);
read_encoded_value_with_base (info->ttype_encoding, info->ttype_base,
info->TType - i, &ptr);
return reinterpret_cast<const std::type_info *>(ptr);
}
#ifdef __ARM_EABI_UNWINDER__
// The ABI provides a routine for matching exception object types.
typedef _Unwind_Control_Block _throw_typet;
#define get_adjusted_ptr(catch_type, throw_type, thrown_ptr_p) \
(__cxa_type_match (throw_type, catch_type, false, thrown_ptr_p) \
!= ctm_failed)
// Return true if THROW_TYPE matches one if the filter types.
static bool
check_exception_spec(lsda_header_info* info, _throw_typet* throw_type,
void* thrown_ptr, _sleb128_t filter_value)
{
const _uleb128_t* e = ((const _uleb128_t*) info->TType)
- filter_value - 1;
while (1)
{
const std::type_info* catch_type;
_uleb128_t tmp;
tmp = *e;
// Zero signals the end of the list. If we've not found
// a match by now, then we've failed the specification.
if (tmp == 0)
return false;
tmp = _Unwind_decode_typeinfo_ptr(info->ttype_base, (_Unwind_Word) e);
// Match a ttype entry.
catch_type = reinterpret_cast<const std::type_info*>(tmp);
// ??? There is currently no way to ask the RTTI code about the
// relationship between two types without reference to a specific
// object. There should be; then we wouldn't need to mess with
// thrown_ptr here.
if (get_adjusted_ptr(catch_type, throw_type, &thrown_ptr))
return true;
// Advance to the next entry.
e++;
}
}
// Save stage1 handler information in the exception object
static inline void
save_caught_exception(struct _Unwind_Exception* ue_header,
struct _Unwind_Context* context,
void* thrown_ptr,
int handler_switch_value,
const unsigned char* language_specific_data,
_Unwind_Ptr landing_pad,
const unsigned char* action_record
__attribute__((__unused__)))
{
ue_header->barrier_cache.sp = _Unwind_GetGR(context, UNWIND_STACK_REG);
ue_header->barrier_cache.bitpattern[0] = (_uw) thrown_ptr;
ue_header->barrier_cache.bitpattern[1]
= (_uw) handler_switch_value;
ue_header->barrier_cache.bitpattern[2]
= (_uw) language_specific_data;
ue_header->barrier_cache.bitpattern[3] = (_uw) landing_pad;
}
// Restore the catch handler data saved during phase1.
static inline void
restore_caught_exception(struct _Unwind_Exception* ue_header,
int& handler_switch_value,
const unsigned char*& language_specific_data,
_Unwind_Ptr& landing_pad)
{
handler_switch_value = (int) ue_header->barrier_cache.bitpattern[1];
language_specific_data =
(const unsigned char*) ue_header->barrier_cache.bitpattern[2];
landing_pad = (_Unwind_Ptr) ue_header->barrier_cache.bitpattern[3];
}
#define CONTINUE_UNWINDING \
do \
{ \
if (__gnu_unwind_frame(ue_header, context) != _URC_OK) \
return _URC_FAILURE; \
return _URC_CONTINUE_UNWIND; \
} \
while (0)
// Return true if the filter spec is empty, ie throw().
static bool
empty_exception_spec (lsda_header_info *info, _Unwind_Sword filter_value)
{
const _Unwind_Word* e = ((const _Unwind_Word*) info->TType)
- filter_value - 1;
return *e == 0;
}
#else
typedef const std::type_info _throw_typet;
// Given the thrown type THROW_TYPE, pointer to a variable containing a
// pointer to the exception object THROWN_PTR_P and a type CATCH_TYPE to
// compare against, return whether or not there is a match and if so,
// update *THROWN_PTR_P.
static bool
get_adjusted_ptr (const std::type_info *catch_type,
const std::type_info *throw_type,
void **thrown_ptr_p)
{
void *thrown_ptr = *thrown_ptr_p;
// Pointer types need to adjust the actual pointer, not
// the pointer to pointer that is the exception object.
// This also has the effect of passing pointer types
// "by value" through the __cxa_begin_catch return value.
if (throw_type->__is_pointer_p ())
thrown_ptr = *(void **) thrown_ptr;
if (catch_type->__do_catch (throw_type, &thrown_ptr, 1))
{
*thrown_ptr_p = thrown_ptr;
return true;
}
return false;
}
// Return true if THROW_TYPE matches one if the filter types.
static bool
check_exception_spec(lsda_header_info* info, _throw_typet* throw_type,
void* thrown_ptr, _sleb128_t filter_value)
{
const unsigned char *e = info->TType - filter_value - 1;
while (1)
{
const std::type_info *catch_type;
_uleb128_t tmp;
e = read_uleb128 (e, &tmp);
// Zero signals the end of the list. If we've not found
// a match by now, then we've failed the specification.
if (tmp == 0)
return false;
// Match a ttype entry.
catch_type = get_ttype_entry (info, tmp);
// ??? There is currently no way to ask the RTTI code about the
// relationship between two types without reference to a specific
// object. There should be; then we wouldn't need to mess with
// thrown_ptr here.
if (get_adjusted_ptr (catch_type, throw_type, &thrown_ptr))
return true;
}
}
// Save stage1 handler information in the exception object
static inline void
save_caught_exception(struct _Unwind_Exception* ue_header,
struct _Unwind_Context* context
__attribute__((__unused__)),
void* thrown_ptr,
int handler_switch_value,
const unsigned char* language_specific_data,
_Unwind_Ptr landing_pad __attribute__((__unused__)),
const unsigned char* action_record)
{
__cxa_exception* xh = __get_exception_header_from_ue(ue_header);
xh->handlerSwitchValue = handler_switch_value;
xh->actionRecord = action_record;
xh->languageSpecificData = language_specific_data;
xh->adjustedPtr = thrown_ptr;
// ??? Completely unknown what this field is supposed to be for.
// ??? Need to cache TType encoding base for call_unexpected.
xh->catchTemp = landing_pad;
}
// Restore the catch handler information saved during phase1.
static inline void
restore_caught_exception(struct _Unwind_Exception* ue_header,
int& handler_switch_value,
const unsigned char*& language_specific_data,
_Unwind_Ptr& landing_pad)
{
__cxa_exception* xh = __get_exception_header_from_ue(ue_header);
handler_switch_value = xh->handlerSwitchValue;
language_specific_data = xh->languageSpecificData;
landing_pad = (_Unwind_Ptr) xh->catchTemp;
}
#define CONTINUE_UNWINDING return _URC_CONTINUE_UNWIND
// Return true if the filter spec is empty, ie throw().
static bool
empty_exception_spec (lsda_header_info *info, _Unwind_Sword filter_value)
{
const unsigned char *e = info->TType - filter_value - 1;
_uleb128_t tmp;
e = read_uleb128 (e, &tmp);
return tmp == 0;
}
#endif // !__ARM_EABI_UNWINDER__
namespace __cxxabiv1
{
// Using a different personality function name causes link failures
// when trying to mix code using different exception handling models.
#ifdef _GLIBCXX_SJLJ_EXCEPTIONS
#define PERSONALITY_FUNCTION __gxx_personality_sj0
#define __builtin_eh_return_data_regno(x) x
#else
#define PERSONALITY_FUNCTION __gxx_personality_v0
#endif
extern "C" _Unwind_Reason_Code
#ifdef __ARM_EABI_UNWINDER__
PERSONALITY_FUNCTION (_Unwind_State state,
struct _Unwind_Exception* ue_header,
struct _Unwind_Context* context)
#else
PERSONALITY_FUNCTION (int version,
_Unwind_Action actions,
_Unwind_Exception_Class exception_class,
struct _Unwind_Exception *ue_header,
struct _Unwind_Context *context)
#endif
{
enum found_handler_type
{
found_nothing,
found_terminate,
found_cleanup,
found_handler
} found_type;
lsda_header_info info;
const unsigned char *language_specific_data;
const unsigned char *action_record;
const unsigned char *p;
_Unwind_Ptr landing_pad, ip;
int handler_switch_value;
void* thrown_ptr = 0;
bool foreign_exception;
int ip_before_insn = 0;
#ifdef __ARM_EABI_UNWINDER__
_Unwind_Action actions;
switch (state & _US_ACTION_MASK)
{
case _US_VIRTUAL_UNWIND_FRAME:
actions = _UA_SEARCH_PHASE;
break;
case _US_UNWIND_FRAME_STARTING:
actions = _UA_CLEANUP_PHASE;
if (!(state & _US_FORCE_UNWIND)
&& ue_header->barrier_cache.sp == _Unwind_GetGR(context,
UNWIND_STACK_REG))
actions |= _UA_HANDLER_FRAME;
break;
case _US_UNWIND_FRAME_RESUME:
CONTINUE_UNWINDING;
break;
default:
std::abort();
}
actions |= state & _US_FORCE_UNWIND;
// We don't know which runtime we're working with, so can't check this.
// However the ABI routines hide this from us, and we don't actually need
// to know.
foreign_exception = false;
// 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 a
// virtual scratch register point at the UCB.
ip = (_Unwind_Ptr) ue_header;
_Unwind_SetGR(context, UNWIND_POINTER_REG, ip);
#else
__cxa_exception* xh = __get_exception_header_from_ue(ue_header);
// Interface version check.
if (version != 1)
return _URC_FATAL_PHASE1_ERROR;
foreign_exception = !__is_gxx_exception_class(exception_class);
#endif
// Shortcut for phase 2 found handler for domestic exception.
if (actions == (_UA_CLEANUP_PHASE | _UA_HANDLER_FRAME)
&& !foreign_exception)
{
restore_caught_exception(ue_header, handler_switch_value,
language_specific_data, landing_pad);
found_type = (landing_pad == 0 ? found_terminate : found_handler);
goto install_context;
}
language_specific_data = (const unsigned char *)
_Unwind_GetLanguageSpecificData (context);
// If no LSDA, then there are no handlers or cleanups.
if (! language_specific_data)
CONTINUE_UNWINDING;
// Parse the LSDA header.
p = parse_lsda_header (context, language_specific_data, &info);
info.ttype_base = base_of_encoded_value (info.ttype_encoding, context);
#ifdef _GLIBCXX_HAVE_GETIPINFO
ip = _Unwind_GetIPInfo (context, &ip_before_insn);
#else
ip = _Unwind_GetIP (context);
#endif
if (! ip_before_insn)
--ip;
landing_pad = 0;
action_record = 0;
handler_switch_value = 0;
#ifdef _GLIBCXX_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 ((int) ip < 0)
return _URC_CONTINUE_UNWIND;
else if (ip == 0)
{
// Fall through to set found_terminate.
}
else
{
_uleb128_t cs_lp, cs_action;
do
{
p = read_uleb128 (p, &cs_lp);
p = read_uleb128 (p, &cs_action);
}
while (--ip);
// Can never have null landing pad for sjlj -- that would have
// been indicated by a -1 call site index.
landing_pad = cs_lp + 1;
if (cs_action)
action_record = info.action_table + cs_action - 1;
goto found_something;
}
#else
// Search the call-site table for the action associated with this IP.
while (p < info.action_table)
{
_Unwind_Ptr cs_start, cs_len, cs_lp;
_uleb128_t cs_action;
// Note that all call-site encodings are "absolute" displacements.
p = read_encoded_value (0, info.call_site_encoding, p, &cs_start);
p = read_encoded_value (0, info.call_site_encoding, p, &cs_len);
p = read_encoded_value (0, info.call_site_encoding, p, &cs_lp);
p = read_uleb128 (p, &cs_action);
// The table is sorted, so if we've passed the ip, stop.
if (ip < info.Start + cs_start)
p = info.action_table;
else if (ip < info.Start + cs_start + cs_len)
{
if (cs_lp)
landing_pad = info.LPStart + cs_lp;
if (cs_action)
action_record = info.action_table + cs_action - 1;
goto found_something;
}
}
#endif // _GLIBCXX_SJLJ_EXCEPTIONS
// If ip is not present in the table, call terminate. This is for
// a destructor inside a cleanup, or a library routine the compiler
// was not expecting to throw.
found_type = found_terminate;
goto do_something;
found_something:
if (landing_pad == 0)
{
// If ip is present, and has a null landing pad, there are
// no cleanups or handlers to be run.
found_type = found_nothing;
}
else if (action_record == 0)
{
// 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.
found_type = found_cleanup;
}
else
{
// Otherwise we have a catch handler or exception specification.
_sleb128_t ar_filter, ar_disp;
const std::type_info* catch_type;
_throw_typet* throw_type;
bool saw_cleanup = false;
bool saw_handler = false;
#ifdef __ARM_EABI_UNWINDER__
// ??? How does this work - more importantly, how does it interact with
// dependent exceptions?
throw_type = ue_header;
if (actions & _UA_FORCE_UNWIND)
{
__GXX_INIT_FORCED_UNWIND_CLASS(ue_header->exception_class);
}
else if (!foreign_exception)
thrown_ptr = __get_object_from_ue (ue_header);
#else
#ifdef __GXX_RTTI
// During forced unwinding, match a magic exception type.
if (actions & _UA_FORCE_UNWIND)
{
throw_type = &typeid(abi::__forced_unwind);
}
// With a foreign exception class, there's no exception type.
// ??? What to do about GNU Java and GNU Ada exceptions?
else if (foreign_exception)
{
throw_type = &typeid(abi::__foreign_exception);
}
else
#endif
{
thrown_ptr = __get_object_from_ue (ue_header);
throw_type = __get_exception_header_from_obj
(thrown_ptr)->exceptionType;
}
#endif
while (1)
{
p = action_record;
p = read_sleb128 (p, &ar_filter);
read_sleb128 (p, &ar_disp);
if (ar_filter == 0)
{
// Zero filter values are cleanups.
saw_cleanup = true;
}
else if (ar_filter > 0)
{
// Positive filter values are handlers.
catch_type = get_ttype_entry (&info, ar_filter);
// Null catch type is a catch-all handler; we can catch foreign
// exceptions with this. Otherwise we must match types.
if (! catch_type
|| (throw_type
&& get_adjusted_ptr (catch_type, throw_type,
&thrown_ptr)))
{
saw_handler = true;
break;
}
}
else
{
// Negative filter values are exception specifications.
// ??? How do foreign exceptions fit in? As far as I can
// see we can't match because there's no __cxa_exception
// object to stuff bits in for __cxa_call_unexpected to use.
// Allow them iff the exception spec is non-empty. I.e.
// a throw() specification results in __unexpected.
if ((throw_type
&& !(actions & _UA_FORCE_UNWIND)
&& !foreign_exception)
? ! check_exception_spec (&info, throw_type, thrown_ptr,
ar_filter)
: empty_exception_spec (&info, ar_filter))
{
saw_handler = true;
break;
}
}
if (ar_disp == 0)
break;
action_record = p + ar_disp;
}
if (saw_handler)
{
handler_switch_value = ar_filter;
found_type = found_handler;
}
else
found_type = (saw_cleanup ? found_cleanup : found_nothing);
}
do_something:
if (found_type == found_nothing)
CONTINUE_UNWINDING;
if (actions & _UA_SEARCH_PHASE)
{
if (found_type == found_cleanup)
CONTINUE_UNWINDING;
// For domestic exceptions, we cache data from phase 1 for phase 2.
if (!foreign_exception)
{
save_caught_exception(ue_header, context, thrown_ptr,
handler_switch_value, language_specific_data,
landing_pad, action_record);
}
return _URC_HANDLER_FOUND;
}
install_context:
// We can't use any of the cxa routines with foreign exceptions,
// because they all expect ue_header to be a struct __cxa_exception.
// So in that case, call terminate or unexpected directly.
if ((actions & _UA_FORCE_UNWIND)
|| foreign_exception)
{
if (found_type == found_terminate)
std::terminate ();
else if (handler_switch_value < 0)
{
__try
{ std::unexpected (); }
__catch(...)
{ std::terminate (); }
}
}
else
{
if (found_type == found_terminate)
__cxa_call_terminate(ue_header);
// Cache the TType base value for __cxa_call_unexpected, as we won't
// have an _Unwind_Context then.
if (handler_switch_value < 0)
{
parse_lsda_header (context, language_specific_data, &info);
info.ttype_base = base_of_encoded_value (info.ttype_encoding,
context);
#ifdef __ARM_EABI_UNWINDER__
const _Unwind_Word* e;
_Unwind_Word n;
e = ((const _Unwind_Word*) info.TType) - handler_switch_value - 1;
// Count the number of rtti objects.
n = 0;
while (e[n] != 0)
n++;
// Count.
ue_header->barrier_cache.bitpattern[1] = n;
// Base
ue_header->barrier_cache.bitpattern[2] = info.ttype_base;
// Stride.
ue_header->barrier_cache.bitpattern[3] = 4;
// List head.
ue_header->barrier_cache.bitpattern[4] = (_Unwind_Word) e;
#else
xh->catchTemp = base_of_encoded_value (info.ttype_encoding, context);
#endif
}
}
/* 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),
__builtin_extend_pointer (ue_header));
_Unwind_SetGR (context, __builtin_eh_return_data_regno (1),
handler_switch_value);
_Unwind_SetIP (context, landing_pad);
#ifdef __ARM_EABI_UNWINDER__
if (found_type == found_cleanup)
__cxa_begin_cleanup(ue_header);
#endif
return _URC_INSTALL_CONTEXT;
}
/* The ARM EABI implementation of __cxa_call_unexpected is in a
different file so that the personality routine (PR) can be used
standalone. The generic routine shared datastructures with the PR
so it is most convenient to implement it here. */
#ifndef __ARM_EABI_UNWINDER__
extern "C" void
__cxa_call_unexpected (void *exc_obj_in)
{
_Unwind_Exception *exc_obj
= reinterpret_cast <_Unwind_Exception *>(exc_obj_in);
__cxa_begin_catch (exc_obj);
// This function is a handler for our exception argument. If we exit
// by throwing a different exception, we'll need the original cleaned up.
struct end_catch_protect
{
end_catch_protect() { }
~end_catch_protect() { __cxa_end_catch(); }
} end_catch_protect_obj;
lsda_header_info info;
__cxa_exception *xh = __get_exception_header_from_ue (exc_obj);
const unsigned char *xh_lsda;
_Unwind_Sword xh_switch_value;
std::terminate_handler xh_terminate_handler;
// If the unexpectedHandler rethrows the exception (e.g. to categorize it),
// it will clobber data about the current handler. So copy the data out now.
xh_lsda = xh->languageSpecificData;
xh_switch_value = xh->handlerSwitchValue;
xh_terminate_handler = xh->terminateHandler;
info.ttype_base = (_Unwind_Ptr) xh->catchTemp;
__try
{ __unexpected (xh->unexpectedHandler); }
__catch(...)
{
// Get the exception thrown from unexpected.
__cxa_eh_globals *globals = __cxa_get_globals_fast ();
__cxa_exception *new_xh = globals->caughtExceptions;
void *new_ptr = __get_object_from_ambiguous_exception (new_xh);
// We don't quite have enough stuff cached; re-parse the LSDA.
parse_lsda_header (0, xh_lsda, &info);
// If this new exception meets the exception spec, allow it.
if (check_exception_spec (&info, __get_exception_header_from_obj
(new_ptr)->exceptionType,
new_ptr, xh_switch_value))
__throw_exception_again;
// If the exception spec allows std::bad_exception, throw that.
// We don't have a thrown object to compare against, but since
// bad_exception doesn't have virtual bases, that's OK; just pass 0.
#if defined(__EXCEPTIONS) && defined(__GXX_RTTI)
const std::type_info &bad_exc = typeid (std::bad_exception);
if (check_exception_spec (&info, &bad_exc, 0, xh_switch_value))
throw std::bad_exception();
#endif
// Otherwise, die.
__terminate (xh_terminate_handler);
}
}
#endif
} // namespace __cxxabiv1