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/* Exception handling and frame unwind runtime interface routines. -*- C -*- |
Copyright (C) 2001-2015 Free Software Foundation, Inc. |
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This file is part of GCC. |
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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. |
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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. |
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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. |
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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/>. */ |
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/* This is derived from the C++ ABI for IA-64. Where we diverge |
for cross-architecture compatibility are noted with "@@@". |
This file is included from unwind-dw2.c, unwind-sjlj.c or |
unwind-ia64.c. */ |
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/* Subroutine of _Unwind_RaiseException also invoked from _Unwind_Resume. |
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Unwind the stack calling the personality routine to find both the |
exception handler and intermediary cleanup code. We'll only locate |
the first such frame here. Cleanup code will call back into |
_Unwind_Resume and we'll continue Phase 2 there. */ |
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static _Unwind_Reason_Code |
_Unwind_RaiseException_Phase2(struct _Unwind_Exception *exc, |
struct _Unwind_Context *context) |
{ |
_Unwind_Reason_Code code; |
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while (1) |
{ |
_Unwind_FrameState fs; |
int match_handler; |
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code = uw_frame_state_for (context, &fs); |
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/* Identify when we've reached the designated handler context. */ |
match_handler = (uw_identify_context (context) == exc->private_2 |
? _UA_HANDLER_FRAME : 0); |
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if (code != _URC_NO_REASON) |
/* Some error encountered. Usually the unwinder doesn't |
diagnose these and merely crashes. */ |
return _URC_FATAL_PHASE2_ERROR; |
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/* Unwind successful. Run the personality routine, if any. */ |
if (fs.personality) |
{ |
code = (*fs.personality) (1, _UA_CLEANUP_PHASE | match_handler, |
exc->exception_class, exc, context); |
if (code == _URC_INSTALL_CONTEXT) |
break; |
if (code != _URC_CONTINUE_UNWIND) |
return _URC_FATAL_PHASE2_ERROR; |
} |
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/* Don't let us unwind past the handler context. */ |
gcc_assert (!match_handler); |
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uw_update_context (context, &fs); |
} |
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return code; |
} |
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/* Raise an exception, passing along the given exception object. */ |
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_Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE |
_Unwind_RaiseException(struct _Unwind_Exception *exc) |
{ |
struct _Unwind_Context this_context, cur_context; |
_Unwind_Reason_Code code; |
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/* Set up this_context to describe the current stack frame. */ |
uw_init_context (&this_context); |
cur_context = this_context; |
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/* Phase 1: Search. Unwind the stack, calling the personality routine |
with the _UA_SEARCH_PHASE flag set. Do not modify the stack yet. */ |
while (1) |
{ |
_Unwind_FrameState fs; |
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/* Set up fs to describe the FDE for the caller of cur_context. The |
first time through the loop, that means __cxa_throw. */ |
code = uw_frame_state_for (&cur_context, &fs); |
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if (code == _URC_END_OF_STACK) |
/* Hit end of stack with no handler found. */ |
return _URC_END_OF_STACK; |
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if (code != _URC_NO_REASON) |
/* Some error encountered. Usually the unwinder doesn't |
diagnose these and merely crashes. */ |
return _URC_FATAL_PHASE1_ERROR; |
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/* Unwind successful. Run the personality routine, if any. */ |
if (fs.personality) |
{ |
code = (*fs.personality) (1, _UA_SEARCH_PHASE, exc->exception_class, |
exc, &cur_context); |
if (code == _URC_HANDLER_FOUND) |
break; |
else if (code != _URC_CONTINUE_UNWIND) |
return _URC_FATAL_PHASE1_ERROR; |
} |
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/* Update cur_context to describe the same frame as fs. */ |
uw_update_context (&cur_context, &fs); |
} |
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/* Indicate to _Unwind_Resume and associated subroutines that this |
is not a forced unwind. Further, note where we found a handler. */ |
exc->private_1 = 0; |
exc->private_2 = uw_identify_context (&cur_context); |
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cur_context = this_context; |
code = _Unwind_RaiseException_Phase2 (exc, &cur_context); |
if (code != _URC_INSTALL_CONTEXT) |
return code; |
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uw_install_context (&this_context, &cur_context); |
} |
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/* Subroutine of _Unwind_ForcedUnwind also invoked from _Unwind_Resume. */ |
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static _Unwind_Reason_Code |
_Unwind_ForcedUnwind_Phase2 (struct _Unwind_Exception *exc, |
struct _Unwind_Context *context) |
{ |
_Unwind_Stop_Fn stop = (_Unwind_Stop_Fn) (_Unwind_Ptr) exc->private_1; |
void *stop_argument = (void *) (_Unwind_Ptr) exc->private_2; |
_Unwind_Reason_Code code, stop_code; |
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while (1) |
{ |
_Unwind_FrameState fs; |
int action; |
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/* Set up fs to describe the FDE for the caller of cur_context. */ |
code = uw_frame_state_for (context, &fs); |
if (code != _URC_NO_REASON && code != _URC_END_OF_STACK) |
return _URC_FATAL_PHASE2_ERROR; |
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/* Unwind successful. */ |
action = _UA_FORCE_UNWIND | _UA_CLEANUP_PHASE; |
if (code == _URC_END_OF_STACK) |
action |= _UA_END_OF_STACK; |
stop_code = (*stop) (1, action, exc->exception_class, exc, |
context, stop_argument); |
if (stop_code != _URC_NO_REASON) |
return _URC_FATAL_PHASE2_ERROR; |
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/* Stop didn't want to do anything. Invoke the personality |
handler, if applicable, to run cleanups. */ |
if (code == _URC_END_OF_STACK) |
break; |
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if (fs.personality) |
{ |
code = (*fs.personality) (1, _UA_FORCE_UNWIND | _UA_CLEANUP_PHASE, |
exc->exception_class, exc, context); |
if (code == _URC_INSTALL_CONTEXT) |
break; |
if (code != _URC_CONTINUE_UNWIND) |
return _URC_FATAL_PHASE2_ERROR; |
} |
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/* Update cur_context to describe the same frame as fs, and discard |
the previous context if necessary. */ |
uw_advance_context (context, &fs); |
} |
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return code; |
} |
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/* Raise an exception for forced unwinding. */ |
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_Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE |
_Unwind_ForcedUnwind (struct _Unwind_Exception *exc, |
_Unwind_Stop_Fn stop, void * stop_argument) |
{ |
struct _Unwind_Context this_context, cur_context; |
_Unwind_Reason_Code code; |
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uw_init_context (&this_context); |
cur_context = this_context; |
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exc->private_1 = (_Unwind_Ptr) stop; |
exc->private_2 = (_Unwind_Ptr) stop_argument; |
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code = _Unwind_ForcedUnwind_Phase2 (exc, &cur_context); |
if (code != _URC_INSTALL_CONTEXT) |
return code; |
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uw_install_context (&this_context, &cur_context); |
} |
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/* Resume propagation of an existing exception. This is used after |
e.g. executing cleanup code, and not to implement rethrowing. */ |
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void LIBGCC2_UNWIND_ATTRIBUTE |
_Unwind_Resume (struct _Unwind_Exception *exc) |
{ |
struct _Unwind_Context this_context, cur_context; |
_Unwind_Reason_Code code; |
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uw_init_context (&this_context); |
cur_context = this_context; |
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/* Choose between continuing to process _Unwind_RaiseException |
or _Unwind_ForcedUnwind. */ |
if (exc->private_1 == 0) |
code = _Unwind_RaiseException_Phase2 (exc, &cur_context); |
else |
code = _Unwind_ForcedUnwind_Phase2 (exc, &cur_context); |
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gcc_assert (code == _URC_INSTALL_CONTEXT); |
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uw_install_context (&this_context, &cur_context); |
} |
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/* Resume propagation of an FORCE_UNWIND exception, or to rethrow |
a normal exception that was handled. */ |
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_Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE |
_Unwind_Resume_or_Rethrow (struct _Unwind_Exception *exc) |
{ |
struct _Unwind_Context this_context, cur_context; |
_Unwind_Reason_Code code; |
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/* Choose between continuing to process _Unwind_RaiseException |
or _Unwind_ForcedUnwind. */ |
if (exc->private_1 == 0) |
return _Unwind_RaiseException (exc); |
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uw_init_context (&this_context); |
cur_context = this_context; |
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code = _Unwind_ForcedUnwind_Phase2 (exc, &cur_context); |
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gcc_assert (code == _URC_INSTALL_CONTEXT); |
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uw_install_context (&this_context, &cur_context); |
} |
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/* A convenience function that calls the exception_cleanup field. */ |
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void |
_Unwind_DeleteException (struct _Unwind_Exception *exc) |
{ |
if (exc->exception_cleanup) |
(*exc->exception_cleanup) (_URC_FOREIGN_EXCEPTION_CAUGHT, exc); |
} |
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/* Perform stack backtrace through unwind data. */ |
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_Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE |
_Unwind_Backtrace(_Unwind_Trace_Fn trace, void * trace_argument) |
{ |
struct _Unwind_Context context; |
_Unwind_Reason_Code code; |
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uw_init_context (&context); |
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while (1) |
{ |
_Unwind_FrameState fs; |
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/* Set up fs to describe the FDE for the caller of context. */ |
code = uw_frame_state_for (&context, &fs); |
if (code != _URC_NO_REASON && code != _URC_END_OF_STACK) |
return _URC_FATAL_PHASE1_ERROR; |
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/* Call trace function. */ |
if ((*trace) (&context, trace_argument) != _URC_NO_REASON) |
return _URC_FATAL_PHASE1_ERROR; |
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/* We're done at end of stack. */ |
if (code == _URC_END_OF_STACK) |
break; |
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/* Update context to describe the same frame as fs. */ |
uw_update_context (&context, &fs); |
} |
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return code; |
} |