320 lines
9.6 KiB
C
320 lines
9.6 KiB
C
/* Exception handling and frame unwind runtime interface routines. -*- C -*-
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Copyright (C) 2001-2020 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
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under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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GCC is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
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License for more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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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
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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/* This is derived from the C++ ABI for IA-64. Where we diverge
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for cross-architecture compatibility are noted with "@@@".
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This file is included from unwind-dw2.c, unwind-sjlj.c or
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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
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exception handler and intermediary cleanup code. We'll only locate
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the first such frame here. Cleanup code will call back into
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_Unwind_Resume and we'll continue Phase 2 there. */
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static _Unwind_Reason_Code
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_Unwind_RaiseException_Phase2(struct _Unwind_Exception *exc,
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struct _Unwind_Context *context,
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unsigned long *frames_p)
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{
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_Unwind_Reason_Code code;
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unsigned long frames = 1;
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while (1)
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{
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_Unwind_FrameState fs;
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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. */
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match_handler = (uw_identify_context (context) == exc->private_2
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? _UA_HANDLER_FRAME : 0);
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if (code != _URC_NO_REASON)
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/* Some error encountered. Usually the unwinder doesn't
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diagnose these and merely crashes. */
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return _URC_FATAL_PHASE2_ERROR;
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/* Unwind successful. Run the personality routine, if any. */
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if (fs.personality)
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{
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code = (*fs.personality) (1, _UA_CLEANUP_PHASE | match_handler,
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exc->exception_class, exc, context);
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if (code == _URC_INSTALL_CONTEXT)
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break;
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if (code != _URC_CONTINUE_UNWIND)
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return _URC_FATAL_PHASE2_ERROR;
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}
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/* Don't let us unwind past the handler context. */
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gcc_assert (!match_handler);
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uw_update_context (context, &fs);
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_Unwind_Frames_Increment (context, frames);
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}
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*frames_p = frames;
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return code;
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}
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/* Raise an exception, passing along the given exception object. */
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_Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
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_Unwind_RaiseException(struct _Unwind_Exception *exc)
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{
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struct _Unwind_Context this_context, cur_context;
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_Unwind_Reason_Code code;
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unsigned long frames;
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/* Set up this_context to describe the current stack frame. */
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uw_init_context (&this_context);
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cur_context = this_context;
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/* Phase 1: Search. Unwind the stack, calling the personality routine
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with the _UA_SEARCH_PHASE flag set. Do not modify the stack yet. */
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while (1)
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{
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_Unwind_FrameState fs;
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/* Set up fs to describe the FDE for the caller of cur_context. The
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first time through the loop, that means __cxa_throw. */
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code = uw_frame_state_for (&cur_context, &fs);
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if (code == _URC_END_OF_STACK)
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/* Hit end of stack with no handler found. */
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return _URC_END_OF_STACK;
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if (code != _URC_NO_REASON)
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/* Some error encountered. Usually the unwinder doesn't
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diagnose these and merely crashes. */
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return _URC_FATAL_PHASE1_ERROR;
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/* Unwind successful. Run the personality routine, if any. */
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if (fs.personality)
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{
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code = (*fs.personality) (1, _UA_SEARCH_PHASE, exc->exception_class,
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exc, &cur_context);
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if (code == _URC_HANDLER_FOUND)
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break;
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else if (code != _URC_CONTINUE_UNWIND)
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return _URC_FATAL_PHASE1_ERROR;
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}
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/* Update cur_context to describe the same frame as fs. */
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uw_update_context (&cur_context, &fs);
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}
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/* Indicate to _Unwind_Resume and associated subroutines that this
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is not a forced unwind. Further, note where we found a handler. */
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exc->private_1 = 0;
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exc->private_2 = uw_identify_context (&cur_context);
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cur_context = this_context;
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code = _Unwind_RaiseException_Phase2 (exc, &cur_context, &frames);
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if (code != _URC_INSTALL_CONTEXT)
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return code;
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uw_install_context (&this_context, &cur_context, frames);
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}
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/* Subroutine of _Unwind_ForcedUnwind also invoked from _Unwind_Resume. */
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static _Unwind_Reason_Code
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_Unwind_ForcedUnwind_Phase2 (struct _Unwind_Exception *exc,
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struct _Unwind_Context *context,
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unsigned long *frames_p)
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{
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_Unwind_Stop_Fn stop = (_Unwind_Stop_Fn) (_Unwind_Ptr) exc->private_1;
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void *stop_argument = (void *) (_Unwind_Ptr) exc->private_2;
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_Unwind_Reason_Code code, stop_code;
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unsigned long frames = 1;
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while (1)
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{
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_Unwind_FrameState fs;
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int action;
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/* Set up fs to describe the FDE for the caller of cur_context. */
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code = uw_frame_state_for (context, &fs);
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if (code != _URC_NO_REASON && code != _URC_END_OF_STACK)
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return _URC_FATAL_PHASE2_ERROR;
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/* Unwind successful. */
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action = _UA_FORCE_UNWIND | _UA_CLEANUP_PHASE;
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if (code == _URC_END_OF_STACK)
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action |= _UA_END_OF_STACK;
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stop_code = (*stop) (1, action, exc->exception_class, exc,
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context, stop_argument);
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if (stop_code != _URC_NO_REASON)
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return _URC_FATAL_PHASE2_ERROR;
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/* Stop didn't want to do anything. Invoke the personality
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handler, if applicable, to run cleanups. */
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if (code == _URC_END_OF_STACK)
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break;
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if (fs.personality)
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{
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code = (*fs.personality) (1, _UA_FORCE_UNWIND | _UA_CLEANUP_PHASE,
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exc->exception_class, exc, context);
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if (code == _URC_INSTALL_CONTEXT)
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break;
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if (code != _URC_CONTINUE_UNWIND)
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return _URC_FATAL_PHASE2_ERROR;
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}
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/* Update cur_context to describe the same frame as fs, and discard
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the previous context if necessary. */
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uw_advance_context (context, &fs);
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_Unwind_Frames_Increment (context, frames);
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}
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*frames_p = frames;
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return code;
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}
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/* Raise an exception for forced unwinding. */
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_Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
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_Unwind_ForcedUnwind (struct _Unwind_Exception *exc,
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_Unwind_Stop_Fn stop, void * stop_argument)
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{
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struct _Unwind_Context this_context, cur_context;
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_Unwind_Reason_Code code;
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unsigned long frames;
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uw_init_context (&this_context);
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cur_context = this_context;
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exc->private_1 = (_Unwind_Ptr) stop;
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exc->private_2 = (_Unwind_Ptr) stop_argument;
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code = _Unwind_ForcedUnwind_Phase2 (exc, &cur_context, &frames);
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if (code != _URC_INSTALL_CONTEXT)
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return code;
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uw_install_context (&this_context, &cur_context, frames);
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}
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/* Resume propagation of an existing exception. This is used after
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e.g. executing cleanup code, and not to implement rethrowing. */
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void LIBGCC2_UNWIND_ATTRIBUTE
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_Unwind_Resume (struct _Unwind_Exception *exc)
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{
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struct _Unwind_Context this_context, cur_context;
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_Unwind_Reason_Code code;
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unsigned long frames;
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uw_init_context (&this_context);
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cur_context = this_context;
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/* Choose between continuing to process _Unwind_RaiseException
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or _Unwind_ForcedUnwind. */
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if (exc->private_1 == 0)
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code = _Unwind_RaiseException_Phase2 (exc, &cur_context, &frames);
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else
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code = _Unwind_ForcedUnwind_Phase2 (exc, &cur_context, &frames);
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gcc_assert (code == _URC_INSTALL_CONTEXT);
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uw_install_context (&this_context, &cur_context, frames);
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}
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/* Resume propagation of an FORCE_UNWIND exception, or to rethrow
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a normal exception that was handled. */
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_Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
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_Unwind_Resume_or_Rethrow (struct _Unwind_Exception *exc)
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{
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struct _Unwind_Context this_context, cur_context;
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_Unwind_Reason_Code code;
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unsigned long frames;
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/* Choose between continuing to process _Unwind_RaiseException
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or _Unwind_ForcedUnwind. */
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if (exc->private_1 == 0)
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return _Unwind_RaiseException (exc);
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uw_init_context (&this_context);
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cur_context = this_context;
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code = _Unwind_ForcedUnwind_Phase2 (exc, &cur_context, &frames);
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gcc_assert (code == _URC_INSTALL_CONTEXT);
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uw_install_context (&this_context, &cur_context, frames);
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}
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/* A convenience function that calls the exception_cleanup field. */
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void
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_Unwind_DeleteException (struct _Unwind_Exception *exc)
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{
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if (exc->exception_cleanup)
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(*exc->exception_cleanup) (_URC_FOREIGN_EXCEPTION_CAUGHT, exc);
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}
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/* Perform stack backtrace through unwind data. */
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_Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
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_Unwind_Backtrace(_Unwind_Trace_Fn trace, void * trace_argument)
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{
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struct _Unwind_Context context;
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_Unwind_Reason_Code code;
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uw_init_context (&context);
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while (1)
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{
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_Unwind_FrameState fs;
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/* Set up fs to describe the FDE for the caller of context. */
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code = uw_frame_state_for (&context, &fs);
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if (code != _URC_NO_REASON && code != _URC_END_OF_STACK)
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return _URC_FATAL_PHASE1_ERROR;
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/* Call trace function. */
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if ((*trace) (&context, trace_argument) != _URC_NO_REASON)
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return _URC_FATAL_PHASE1_ERROR;
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/* We're done at end of stack. */
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if (code == _URC_END_OF_STACK)
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break;
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/* Update context to describe the same frame as fs. */
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uw_update_context (&context, &fs);
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}
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return code;
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}
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