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/* Supporting functions for C exception handling.
Copyright (C) 2002, 2003 Free Software Foundation, Inc.
Contributed by Aldy Hernandez <aldy@quesejoda.com>.
Shamelessly stolen from the Java front end.
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 2, 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.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING. If not, write to the Free
Software Foundation, 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA. */
#include "tconfig.h"
#include "tsystem.h"
#include "unwind.h"
#include "unwind-pe.h"
typedef struct
{
_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;
} lsda_header_info;
static const unsigned char *
parse_lsda_header (struct _Unwind_Context *context, const unsigned char *p,
lsda_header_info *info)
{
_Unwind_Word 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)
{
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;
}
#ifdef __USING_SJLJ_EXCEPTIONS__
#define PERSONALITY_FUNCTION __gcc_personality_sj0
#define __builtin_eh_return_data_regno(x) x
#else
#define PERSONALITY_FUNCTION __gcc_personality_v0
#endif
#define PERSONALITY_FUNCTION __gcc_personality_v0
_Unwind_Reason_Code
PERSONALITY_FUNCTION (int, _Unwind_Action, _Unwind_Exception_Class,
struct _Unwind_Exception *, struct _Unwind_Context *);
_Unwind_Reason_Code
PERSONALITY_FUNCTION (int version,
_Unwind_Action actions,
_Unwind_Exception_Class exception_class ATTRIBUTE_UNUSED,
struct _Unwind_Exception *ue_header,
struct _Unwind_Context *context)
{
lsda_header_info info;
const unsigned char *language_specific_data, *p, *action_record;
_Unwind_Ptr landing_pad, ip;
if (version != 1)
return _URC_FATAL_PHASE1_ERROR;
/* Currently we only support cleanups for C. */
if ((actions & _UA_CLEANUP_PHASE) == 0)
return _URC_CONTINUE_UNWIND;
language_specific_data = (const unsigned char *)
_Unwind_GetLanguageSpecificData (context);
/* If no LSDA, then there are no handlers or cleanups. */
if (! language_specific_data)
return _URC_CONTINUE_UNWIND;
/* Parse the LSDA header. */
p = parse_lsda_header (context, language_specific_data, &info);
ip = _Unwind_GetIP (context) - 1;
landing_pad = 0;
#ifdef __USING_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
{
_Unwind_Word 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;
_Unwind_Word 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
/* IP is not in table. No associated cleanups. */
/* ??? This is where C++ calls std::terminate to catch throw
from a destructor. */
return _URC_CONTINUE_UNWIND;
found_something:
if (landing_pad == 0)
{
/* IP is present, but has a null landing pad.
No handler to be run. */
return _URC_CONTINUE_UNWIND;
}
_Unwind_SetGR (context, __builtin_eh_return_data_regno (0),
(_Unwind_Ptr) ue_header);
_Unwind_SetGR (context, __builtin_eh_return_data_regno (1), 0);
_Unwind_SetIP (context, landing_pad);
return _URC_INSTALL_CONTEXT;
}
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