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[/] [openrisc/] [trunk/] [gnu-old/] [gcc-4.2.2/] [gcc/] [unwind-pe.h] - Blame information for rev 816

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/* Exception handling and frame unwind runtime interface routines.
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   Copyright (C) 2001, 2002, 2003, 2004 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 2, or (at your option)
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   any later version.
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   In addition to the permissions in the GNU General Public License, the
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   Free Software Foundation gives you unlimited permission to link the
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   compiled version of this file into combinations with other programs,
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   and to distribute those combinations without any restriction coming
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   from the use of this file.  (The General Public License restrictions
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   do apply in other respects; for example, they cover modification of
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   the file, and distribution when not linked into a combined
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   executable.)
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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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   You should have received a copy of the GNU General Public License
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   along with GCC; see the file COPYING.  If not, write to the Free
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   Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
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   02110-1301, USA.  */
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/* @@@ Really this should be out of line, but this also causes link
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   compatibility problems with the base ABI.  This is slightly better
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   than duplicating code, however.  */
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#ifndef GCC_UNWIND_PE_H
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#define GCC_UNWIND_PE_H
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/* If using C++, references to abort have to be qualified with std::.  */
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#if __cplusplus
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#define __gxx_abort std::abort
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#else
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#define __gxx_abort abort
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#endif
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/* Pointer encodings, from dwarf2.h.  */
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#define DW_EH_PE_absptr         0x00
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#define DW_EH_PE_omit           0xff
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#define DW_EH_PE_uleb128        0x01
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#define DW_EH_PE_udata2         0x02
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#define DW_EH_PE_udata4         0x03
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#define DW_EH_PE_udata8         0x04
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#define DW_EH_PE_sleb128        0x09
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#define DW_EH_PE_sdata2         0x0A
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#define DW_EH_PE_sdata4         0x0B
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#define DW_EH_PE_sdata8         0x0C
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#define DW_EH_PE_signed         0x08
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#define DW_EH_PE_pcrel          0x10
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#define DW_EH_PE_textrel        0x20
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#define DW_EH_PE_datarel        0x30
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#define DW_EH_PE_funcrel        0x40
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#define DW_EH_PE_aligned        0x50
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#define DW_EH_PE_indirect       0x80
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#ifndef NO_SIZE_OF_ENCODED_VALUE
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/* Given an encoding, return the number of bytes the format occupies.
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   This is only defined for fixed-size encodings, and so does not
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   include leb128.  */
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static unsigned int
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size_of_encoded_value (unsigned char encoding)
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{
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  if (encoding == DW_EH_PE_omit)
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    return 0;
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  switch (encoding & 0x07)
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    {
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    case DW_EH_PE_absptr:
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      return sizeof (void *);
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    case DW_EH_PE_udata2:
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      return 2;
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    case DW_EH_PE_udata4:
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      return 4;
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    case DW_EH_PE_udata8:
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      return 8;
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    }
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  __gxx_abort ();
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}
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#endif
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#ifndef NO_BASE_OF_ENCODED_VALUE
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/* Given an encoding and an _Unwind_Context, return the base to which
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   the encoding is relative.  This base may then be passed to
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   read_encoded_value_with_base for use when the _Unwind_Context is
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   not available.  */
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static _Unwind_Ptr
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base_of_encoded_value (unsigned char encoding, struct _Unwind_Context *context)
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{
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  if (encoding == DW_EH_PE_omit)
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    return 0;
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  switch (encoding & 0x70)
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    {
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    case DW_EH_PE_absptr:
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    case DW_EH_PE_pcrel:
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    case DW_EH_PE_aligned:
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      return 0;
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    case DW_EH_PE_textrel:
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      return _Unwind_GetTextRelBase (context);
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    case DW_EH_PE_datarel:
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      return _Unwind_GetDataRelBase (context);
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    case DW_EH_PE_funcrel:
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      return _Unwind_GetRegionStart (context);
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    }
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  __gxx_abort ();
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}
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#endif
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/* Read an unsigned leb128 value from P, store the value in VAL, return
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   P incremented past the value.  We assume that a word is large enough to
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   hold any value so encoded; if it is smaller than a pointer on some target,
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   pointers should not be leb128 encoded on that target.  */
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static const unsigned char *
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read_uleb128 (const unsigned char *p, _Unwind_Word *val)
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{
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  unsigned int shift = 0;
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  unsigned char byte;
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  _Unwind_Word result;
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  result = 0;
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  do
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    {
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      byte = *p++;
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      result |= ((_Unwind_Word)byte & 0x7f) << shift;
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      shift += 7;
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    }
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  while (byte & 0x80);
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  *val = result;
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  return p;
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}
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/* Similar, but read a signed leb128 value.  */
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static const unsigned char *
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read_sleb128 (const unsigned char *p, _Unwind_Sword *val)
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{
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  unsigned int shift = 0;
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  unsigned char byte;
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  _Unwind_Word result;
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  result = 0;
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  do
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    {
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      byte = *p++;
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      result |= ((_Unwind_Word)byte & 0x7f) << shift;
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      shift += 7;
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    }
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  while (byte & 0x80);
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  /* Sign-extend a negative value.  */
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  if (shift < 8 * sizeof(result) && (byte & 0x40) != 0)
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    result |= -(((_Unwind_Word)1L) << shift);
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  *val = (_Unwind_Sword) result;
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  return p;
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}
177
 
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/* Load an encoded value from memory at P.  The value is returned in VAL;
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   The function returns P incremented past the value.  BASE is as given
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   by base_of_encoded_value for this encoding in the appropriate context.  */
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static const unsigned char *
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read_encoded_value_with_base (unsigned char encoding, _Unwind_Ptr base,
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                              const unsigned char *p, _Unwind_Ptr *val)
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{
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  union unaligned
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    {
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      void *ptr;
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      unsigned u2 __attribute__ ((mode (HI)));
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      unsigned u4 __attribute__ ((mode (SI)));
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      unsigned u8 __attribute__ ((mode (DI)));
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      signed s2 __attribute__ ((mode (HI)));
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      signed s4 __attribute__ ((mode (SI)));
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      signed s8 __attribute__ ((mode (DI)));
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    } __attribute__((__packed__));
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  const union unaligned *u = (const union unaligned *) p;
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  _Unwind_Internal_Ptr result;
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  if (encoding == DW_EH_PE_aligned)
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    {
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      _Unwind_Internal_Ptr a = (_Unwind_Internal_Ptr) p;
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      a = (a + sizeof (void *) - 1) & - sizeof(void *);
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      result = *(_Unwind_Internal_Ptr *) a;
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      p = (const unsigned char *) (_Unwind_Internal_Ptr) (a + sizeof (void *));
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    }
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  else
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    {
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      switch (encoding & 0x0f)
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        {
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        case DW_EH_PE_absptr:
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          result = (_Unwind_Internal_Ptr) u->ptr;
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          p += sizeof (void *);
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          break;
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        case DW_EH_PE_uleb128:
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          {
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            _Unwind_Word tmp;
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            p = read_uleb128 (p, &tmp);
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            result = (_Unwind_Internal_Ptr) tmp;
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          }
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          break;
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        case DW_EH_PE_sleb128:
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          {
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            _Unwind_Sword tmp;
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            p = read_sleb128 (p, &tmp);
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            result = (_Unwind_Internal_Ptr) tmp;
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          }
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          break;
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        case DW_EH_PE_udata2:
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          result = u->u2;
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          p += 2;
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          break;
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        case DW_EH_PE_udata4:
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          result = u->u4;
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          p += 4;
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          break;
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        case DW_EH_PE_udata8:
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          result = u->u8;
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          p += 8;
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          break;
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        case DW_EH_PE_sdata2:
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          result = u->s2;
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          p += 2;
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          break;
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        case DW_EH_PE_sdata4:
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          result = u->s4;
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          p += 4;
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          break;
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        case DW_EH_PE_sdata8:
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          result = u->s8;
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          p += 8;
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          break;
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258
        default:
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          __gxx_abort ();
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        }
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262
      if (result != 0)
263
        {
264
          result += ((encoding & 0x70) == DW_EH_PE_pcrel
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                     ? (_Unwind_Internal_Ptr) u : base);
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          if (encoding & DW_EH_PE_indirect)
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            result = *(_Unwind_Internal_Ptr *) result;
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        }
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    }
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271
  *val = result;
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  return p;
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}
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275
#ifndef NO_BASE_OF_ENCODED_VALUE
276
 
277
/* Like read_encoded_value_with_base, but get the base from the context
278
   rather than providing it directly.  */
279
 
280
static inline const unsigned char *
281
read_encoded_value (struct _Unwind_Context *context, unsigned char encoding,
282
                    const unsigned char *p, _Unwind_Ptr *val)
283
{
284
  return read_encoded_value_with_base (encoding,
285
                base_of_encoded_value (encoding, context),
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                p, val);
287
}
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289
#endif
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#endif /* unwind-pe.h */

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