247 lines
7.4 KiB
C
247 lines
7.4 KiB
C
/* Supporting functions for C exception handling.
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Copyright (C) 2002-2019 Free Software Foundation, Inc.
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Contributed by Aldy Hernandez <aldy@quesejoda.com>.
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Shamelessly stolen from the Java front end.
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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
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 3, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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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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#include "tconfig.h"
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#include "tsystem.h"
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#include "auto-target.h"
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#include "unwind.h"
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#define NO_SIZE_OF_ENCODED_VALUE
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#include "unwind-pe.h"
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typedef struct
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{
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_Unwind_Ptr Start;
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_Unwind_Ptr LPStart;
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_Unwind_Ptr ttype_base;
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const unsigned char *TType;
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const unsigned char *action_table;
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unsigned char ttype_encoding;
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unsigned char call_site_encoding;
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} lsda_header_info;
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static const unsigned char *
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parse_lsda_header (struct _Unwind_Context *context, const unsigned char *p,
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lsda_header_info *info)
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{
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_uleb128_t tmp;
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unsigned char lpstart_encoding;
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info->Start = (context ? _Unwind_GetRegionStart (context) : 0);
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/* Find @LPStart, the base to which landing pad offsets are relative. */
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lpstart_encoding = *p++;
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if (lpstart_encoding != DW_EH_PE_omit)
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p = read_encoded_value (context, lpstart_encoding, p, &info->LPStart);
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else
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info->LPStart = info->Start;
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/* Find @TType, the base of the handler and exception spec type data. */
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info->ttype_encoding = *p++;
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if (info->ttype_encoding != DW_EH_PE_omit)
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{
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p = read_uleb128 (p, &tmp);
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info->TType = p + tmp;
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}
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else
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info->TType = 0;
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/* The encoding and length of the call-site table; the action table
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immediately follows. */
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info->call_site_encoding = *p++;
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p = read_uleb128 (p, &tmp);
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info->action_table = p + tmp;
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return p;
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}
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#ifdef __ARM_EABI_UNWINDER__
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/* ARM EABI personality routines must also unwind the stack. */
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#define CONTINUE_UNWINDING \
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do \
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{ \
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if (__gnu_unwind_frame (ue_header, context) != _URC_OK) \
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return _URC_FAILURE; \
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return _URC_CONTINUE_UNWIND; \
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} \
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while (0)
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#else
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#define CONTINUE_UNWINDING return _URC_CONTINUE_UNWIND
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#endif
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#ifdef __USING_SJLJ_EXCEPTIONS__
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#define PERSONALITY_FUNCTION __gcc_personality_sj0
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#define __builtin_eh_return_data_regno(x) x
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#elif defined(__SEH__)
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#define PERSONALITY_FUNCTION __gcc_personality_imp
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#else
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#define PERSONALITY_FUNCTION __gcc_personality_v0
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#endif
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#ifdef __ARM_EABI_UNWINDER__
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_Unwind_Reason_Code
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PERSONALITY_FUNCTION (_Unwind_State, struct _Unwind_Exception *,
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struct _Unwind_Context *);
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_Unwind_Reason_Code
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__attribute__((target ("general-regs-only")))
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PERSONALITY_FUNCTION (_Unwind_State state,
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struct _Unwind_Exception * ue_header,
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struct _Unwind_Context * context)
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#else
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#if defined (__SEH__) && !defined (__USING_SJLJ_EXCEPTIONS__)
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static
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#endif
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_Unwind_Reason_Code
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PERSONALITY_FUNCTION (int, _Unwind_Action, _Unwind_Exception_Class,
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struct _Unwind_Exception *, struct _Unwind_Context *);
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_Unwind_Reason_Code
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PERSONALITY_FUNCTION (int version,
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_Unwind_Action actions,
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_Unwind_Exception_Class exception_class ATTRIBUTE_UNUSED,
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struct _Unwind_Exception *ue_header,
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struct _Unwind_Context *context)
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#endif
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{
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lsda_header_info info;
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const unsigned char *language_specific_data, *p;
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_Unwind_Ptr landing_pad, ip;
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int ip_before_insn = 0;
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#ifdef __ARM_EABI_UNWINDER__
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if ((state & _US_ACTION_MASK) != _US_UNWIND_FRAME_STARTING)
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CONTINUE_UNWINDING;
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/* The dwarf unwinder assumes the context structure holds things like the
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function and LSDA pointers. The ARM implementation caches these in
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the exception header (UCB). To avoid rewriting everything we make a
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virtual scratch register point at the UCB. */
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ip = (_Unwind_Ptr) ue_header;
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_Unwind_SetGR (context, UNWIND_POINTER_REG, ip);
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#else
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if (version != 1)
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return _URC_FATAL_PHASE1_ERROR;
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/* Currently we only support cleanups for C. */
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if ((actions & _UA_CLEANUP_PHASE) == 0)
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CONTINUE_UNWINDING;
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#endif
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language_specific_data = (const unsigned char *)
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_Unwind_GetLanguageSpecificData (context);
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/* If no LSDA, then there are no handlers or cleanups. */
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if (! language_specific_data)
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CONTINUE_UNWINDING;
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/* Parse the LSDA header. */
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p = parse_lsda_header (context, language_specific_data, &info);
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#ifdef HAVE_GETIPINFO
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ip = _Unwind_GetIPInfo (context, &ip_before_insn);
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#else
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ip = _Unwind_GetIP (context);
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#endif
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if (! ip_before_insn)
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--ip;
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landing_pad = 0;
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#ifdef __USING_SJLJ_EXCEPTIONS__
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/* The given "IP" is an index into the call-site table, with two
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exceptions -- -1 means no-action, and 0 means terminate. But
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since we're using uleb128 values, we've not got random access
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to the array. */
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if ((int) ip <= 0)
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return _URC_CONTINUE_UNWIND;
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else
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{
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_uleb128_t cs_lp, cs_action;
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do
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{
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p = read_uleb128 (p, &cs_lp);
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p = read_uleb128 (p, &cs_action);
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}
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while (--ip);
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/* Can never have null landing pad for sjlj -- that would have
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been indicated by a -1 call site index. */
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landing_pad = (_Unwind_Ptr)cs_lp + 1;
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goto found_something;
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}
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#else
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/* Search the call-site table for the action associated with this IP. */
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while (p < info.action_table)
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{
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_Unwind_Ptr cs_start, cs_len, cs_lp;
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_uleb128_t cs_action;
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/* Note that all call-site encodings are "absolute" displacements. */
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p = read_encoded_value (0, info.call_site_encoding, p, &cs_start);
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p = read_encoded_value (0, info.call_site_encoding, p, &cs_len);
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p = read_encoded_value (0, info.call_site_encoding, p, &cs_lp);
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p = read_uleb128 (p, &cs_action);
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/* The table is sorted, so if we've passed the ip, stop. */
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if (ip < info.Start + cs_start)
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p = info.action_table;
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else if (ip < info.Start + cs_start + cs_len)
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{
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if (cs_lp)
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landing_pad = info.LPStart + cs_lp;
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goto found_something;
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}
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}
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#endif
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/* IP is not in table. No associated cleanups. */
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/* ??? This is where C++ calls std::terminate to catch throw
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from a destructor. */
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CONTINUE_UNWINDING;
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found_something:
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if (landing_pad == 0)
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{
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/* IP is present, but has a null landing pad.
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No handler to be run. */
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CONTINUE_UNWINDING;
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}
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_Unwind_SetGR (context, __builtin_eh_return_data_regno (0),
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(_Unwind_Ptr) ue_header);
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_Unwind_SetGR (context, __builtin_eh_return_data_regno (1), 0);
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_Unwind_SetIP (context, landing_pad);
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return _URC_INSTALL_CONTEXT;
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}
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#if defined (__SEH__) && !defined (__USING_SJLJ_EXCEPTIONS__)
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EXCEPTION_DISPOSITION
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__gcc_personality_seh0 (PEXCEPTION_RECORD ms_exc, void *this_frame,
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PCONTEXT ms_orig_context, PDISPATCHER_CONTEXT ms_disp)
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{
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return _GCC_specific_handler (ms_exc, this_frame, ms_orig_context,
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ms_disp, __gcc_personality_imp);
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}
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#endif /* SEH */
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