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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [libgcc/] [unwind-c.c] - Blame information for rev 734

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1 734 jeremybenn
/* Supporting functions for C exception handling.
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   Copyright (C) 2002, 2003, 2009 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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6
This file is part of GCC.
7
 
8
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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22
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 "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
92
 
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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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#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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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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_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;
124
  _Unwind_Ptr landing_pad, ip;
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  int ip_before_insn = 0;
126
 
127
#ifdef __ARM_EABI_UNWINDER__
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  if ((state & _US_ACTION_MASK) != _US_UNWIND_FRAME_STARTING)
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    CONTINUE_UNWINDING;
130
 
131
  /* The dwarf unwinder assumes the context structure holds things like the
132
     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
134
     virtual scratch register point at the UCB.  */
135
  ip = (_Unwind_Ptr) ue_header;
136
  _Unwind_SetGR (context, UNWIND_POINTER_REG, ip);
137
#else
138
  if (version != 1)
139
    return _URC_FATAL_PHASE1_ERROR;
140
 
141
  /* Currently we only support cleanups for C.  */
142
  if ((actions & _UA_CLEANUP_PHASE) == 0)
143
    CONTINUE_UNWINDING;
144
#endif
145
 
146
  language_specific_data = (const unsigned char *)
147
    _Unwind_GetLanguageSpecificData (context);
148
 
149
  /* If no LSDA, then there are no handlers or cleanups.  */
150
  if (! language_specific_data)
151
    CONTINUE_UNWINDING;
152
 
153
  /* Parse the LSDA header.  */
154
  p = parse_lsda_header (context, language_specific_data, &info);
155
#ifdef HAVE_GETIPINFO
156
  ip = _Unwind_GetIPInfo (context, &ip_before_insn);
157
#else
158
  ip = _Unwind_GetIP (context);
159
#endif
160
  if (! ip_before_insn)
161
    --ip;
162
  landing_pad = 0;
163
 
164
#ifdef __USING_SJLJ_EXCEPTIONS__
165
  /* The given "IP" is an index into the call-site table, with two
166
     exceptions -- -1 means no-action, and 0 means terminate.  But
167
     since we're using uleb128 values, we've not got random access
168
     to the array.  */
169
  if ((int) ip <= 0)
170
    return _URC_CONTINUE_UNWIND;
171
  else
172
    {
173
      _uleb128_t cs_lp, cs_action;
174
      do
175
        {
176
          p = read_uleb128 (p, &cs_lp);
177
          p = read_uleb128 (p, &cs_action);
178
        }
179
      while (--ip);
180
 
181
      /* Can never have null landing pad for sjlj -- that would have
182
         been indicated by a -1 call site index.  */
183
      landing_pad = (_Unwind_Ptr)cs_lp + 1;
184
      goto found_something;
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    }
186
#else
187
  /* Search the call-site table for the action associated with this IP.  */
188
  while (p < info.action_table)
189
    {
190
      _Unwind_Ptr cs_start, cs_len, cs_lp;
191
      _uleb128_t cs_action;
192
 
193
      /* Note that all call-site encodings are "absolute" displacements.  */
194
      p = read_encoded_value (0, info.call_site_encoding, p, &cs_start);
195
      p = read_encoded_value (0, info.call_site_encoding, p, &cs_len);
196
      p = read_encoded_value (0, info.call_site_encoding, p, &cs_lp);
197
      p = read_uleb128 (p, &cs_action);
198
 
199
      /* The table is sorted, so if we've passed the ip, stop.  */
200
      if (ip < info.Start + cs_start)
201
        p = info.action_table;
202
      else if (ip < info.Start + cs_start + cs_len)
203
        {
204
          if (cs_lp)
205
            landing_pad = info.LPStart + cs_lp;
206
          goto found_something;
207
        }
208
    }
209
#endif
210
 
211
  /* IP is not in table.  No associated cleanups.  */
212
  /* ??? This is where C++ calls std::terminate to catch throw
213
     from a destructor.  */
214
  CONTINUE_UNWINDING;
215
 
216
 found_something:
217
  if (landing_pad == 0)
218
    {
219
      /* IP is present, but has a null landing pad.
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         No handler to be run.  */
221
      CONTINUE_UNWINDING;
222
    }
223
 
224
  _Unwind_SetGR (context, __builtin_eh_return_data_regno (0),
225
                 (_Unwind_Ptr) ue_header);
226
  _Unwind_SetGR (context, __builtin_eh_return_data_regno (1), 0);
227
  _Unwind_SetIP (context, landing_pad);
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  return _URC_INSTALL_CONTEXT;
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}

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