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/* DWARF2 exception handling and frame unwind runtime interface routines.

   Copyright (C) 1997-2013 Free Software Foundation, Inc.

   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 3, 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.

   Under Section 7 of GPL version 3, you are granted additional

   permissions described in the GCC Runtime Library Exception, version

   3.1, as published by the Free Software Foundation.

   You should have received a copy of the GNU General Public License and

   a copy of the GCC Runtime Library Exception along with this program;

   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see

   .  */

#include "tconfig.h"

#include "tsystem.h"

#include "coretypes.h"

#include "tm.h"

#include "dwarf2.h"

#include "unwind.h"

#ifdef __USING_SJLJ_EXCEPTIONS__

# define NO_SIZE_OF_ENCODED_VALUE

#endif

#include "unwind-pe.h"

#include "unwind-dw2-fde.h"

#include "gthr.h"

#include "unwind-dw2.h"

#ifndef __USING_SJLJ_EXCEPTIONS__

#ifndef STACK_GROWS_DOWNWARD

#define STACK_GROWS_DOWNWARD 0

#else

#undef STACK_GROWS_DOWNWARD

#define STACK_GROWS_DOWNWARD 1

#endif

/* Dwarf frame registers used for pre gcc 3.0 compiled glibc.  */

#ifndef PRE_GCC3_DWARF_FRAME_REGISTERS

#define PRE_GCC3_DWARF_FRAME_REGISTERS DWARF_FRAME_REGISTERS

#endif

#ifndef DWARF_REG_TO_UNWIND_COLUMN

#define DWARF_REG_TO_UNWIND_COLUMN(REGNO) (REGNO)

#endif

/* ??? For the public function interfaces, we tend to gcc_assert that the

   column numbers are in range.  For the dwarf2 unwind info this does happen,

   although so far in a case that doesn't actually matter.

   See PR49146, in which a call from x86_64 ms abi to x86_64 unix abi stores

   the call-saved xmm registers and annotates them.  We havn't bothered

   providing support for the xmm registers for the x86_64 port primarily

   because the 64-bit windows targets don't use dwarf2 unwind, using sjlj or

   SEH instead.  Adding the support for unix targets would generally be a

   waste.  However, some runtime libraries supplied with ICC do contain such

   an unorthodox transition, as well as the unwind info to match.  This loss

   of register restoration doesn't matter in practice, because the exception

   is caught in the native unix abi, where all of the xmm registers are

   call clobbered.

   Ideally, we'd record some bit to notice when we're failing to restore some

   register recorded in the unwind info, but to do that we need annotation on

   the unix->ms abi edge, so that we know when the register data may be

   discarded.  And since this edge is also within the ICC library, we're

   unlikely to be able to get the new annotation.

   Barring a magic solution to restore the ms abi defined 128-bit xmm registers

   (as distictly opposed to the full runtime width) without causing extra

   overhead for normal unix abis, the best solution seems to be to simply

   ignore unwind data for unknown columns.  */

#define UNWIND_COLUMN_IN_RANGE(x) \

    __builtin_expect((x) <= DWARF_FRAME_REGISTERS, 1)

#ifdef REG_VALUE_IN_UNWIND_CONTEXT

typedef _Unwind_Word _Unwind_Context_Reg_Val;

#ifndef ASSUME_EXTENDED_UNWIND_CONTEXT

#define ASSUME_EXTENDED_UNWIND_CONTEXT 1

#endif

static inline _Unwind_Word

_Unwind_Get_Unwind_Word (_Unwind_Context_Reg_Val val)

{

  return val;

}

static inline _Unwind_Context_Reg_Val

_Unwind_Get_Unwind_Context_Reg_Val (_Unwind_Word val)

{

  return val;

}

#else

typedef void *_Unwind_Context_Reg_Val;

static inline _Unwind_Word

_Unwind_Get_Unwind_Word (_Unwind_Context_Reg_Val val)

{

  return (_Unwind_Word) (_Unwind_Internal_Ptr) val;

}

static inline _Unwind_Context_Reg_Val

_Unwind_Get_Unwind_Context_Reg_Val (_Unwind_Word val)

{

  return (_Unwind_Context_Reg_Val) (_Unwind_Internal_Ptr) val;

}

#endif

#ifndef ASSUME_EXTENDED_UNWIND_CONTEXT

#define ASSUME_EXTENDED_UNWIND_CONTEXT 0

#endif

/* This is the register and unwind state for a particular frame.  This

   provides the information necessary to unwind up past a frame and return

   to its caller.  */

struct _Unwind_Context

{

  _Unwind_Context_Reg_Val reg[DWARF_FRAME_REGISTERS+1];

  void *cfa;

  void *ra;

  void *lsda;

  struct dwarf_eh_bases bases;

  /* Signal frame context.  */

#define SIGNAL_FRAME_BIT ((~(_Unwind_Word) 0 >> 1) + 1)

  /* Context which has version/args_size/by_value fields.  */

#define EXTENDED_CONTEXT_BIT ((~(_Unwind_Word) 0 >> 2) + 1)

  _Unwind_Word flags;

  /* 0 for now, can be increased when further fields are added to

     struct _Unwind_Context.  */

  _Unwind_Word version;

  _Unwind_Word args_size;

  char by_value[DWARF_FRAME_REGISTERS+1];

};

/* Byte size of every register managed by these routines.  */

static unsigned char dwarf_reg_size_table[DWARF_FRAME_REGISTERS+1];

/* Read unaligned data from the instruction buffer.  */

union unaligned

{

  void *p;

  unsigned u2 __attribute__ ((mode (HI)));

  unsigned u4 __attribute__ ((mode (SI)));

  unsigned u8 __attribute__ ((mode (DI)));

  signed s2 __attribute__ ((mode (HI)));

  signed s4 __attribute__ ((mode (SI)));

  signed s8 __attribute__ ((mode (DI)));

} __attribute__ ((packed));

static void uw_update_context (struct _Unwind_Context *, _Unwind_FrameState *);

static _Unwind_Reason_Code uw_frame_state_for (struct _Unwind_Context *,

					       _Unwind_FrameState *);

static inline void *

read_pointer (const void *p) { const union unaligned *up = p; return up->p; }

static inline int

read_1u (const void *p) { return *(const unsigned char *) p; }

static inline int

read_1s (const void *p) { return *(const signed char *) p; }

static inline int

read_2u (const void *p) { const union unaligned *up = p; return up->u2; }

static inline int

read_2s (const void *p) { const union unaligned *up = p; return up->s2; }

static inline unsigned int

read_4u (const void *p) { const union unaligned *up = p; return up->u4; }

static inline int

read_4s (const void *p) { const union unaligned *up = p; return up->s4; }

static inline unsigned long

read_8u (const void *p) { const union unaligned *up = p; return up->u8; }

static inline unsigned long

read_8s (const void *p) { const union unaligned *up = p; return up->s8; }

static inline _Unwind_Word

_Unwind_IsSignalFrame (struct _Unwind_Context *context)

{

  return (context->flags & SIGNAL_FRAME_BIT) ? 1 : 0;

}

static inline void

_Unwind_SetSignalFrame (struct _Unwind_Context *context, int val)

{

  if (val)

    context->flags |= SIGNAL_FRAME_BIT;

  else

    context->flags &= ~SIGNAL_FRAME_BIT;

}

static inline _Unwind_Word

_Unwind_IsExtendedContext (struct _Unwind_Context *context)

{

  return (ASSUME_EXTENDED_UNWIND_CONTEXT

	  || (context->flags & EXTENDED_CONTEXT_BIT));

}

/* Get the value of register INDEX as saved in CONTEXT.  */

inline _Unwind_Word

_Unwind_GetGR (struct _Unwind_Context *context, int index)

{

  int size;

  _Unwind_Context_Reg_Val val;

#ifdef DWARF_ZERO_REG

  if (index == DWARF_ZERO_REG)

    return 0;

#endif

  index = DWARF_REG_TO_UNWIND_COLUMN (index);

  gcc_assert (index < (int) sizeof(dwarf_reg_size_table));

  size = dwarf_reg_size_table[index];

  val = context->reg[index];

  if (_Unwind_IsExtendedContext (context) && context->by_value[index])

    return _Unwind_Get_Unwind_Word (val);

  /* This will segfault if the register hasn't been saved.  */

  if (size == sizeof(_Unwind_Ptr))

    return * (_Unwind_Ptr *) (_Unwind_Internal_Ptr) val;

  else

    {

      gcc_assert (size == sizeof(_Unwind_Word));

      return * (_Unwind_Word *) (_Unwind_Internal_Ptr) val;

    }

}

static inline void *

_Unwind_GetPtr (struct _Unwind_Context *context, int index)

{

  return (void *)(_Unwind_Ptr) _Unwind_GetGR (context, index);

}

/* Get the value of the CFA as saved in CONTEXT.  */

_Unwind_Word

_Unwind_GetCFA (struct _Unwind_Context *context)

{

  return (_Unwind_Ptr) context->cfa;

}

/* Overwrite the saved value for register INDEX in CONTEXT with VAL.  */

inline void

_Unwind_SetGR (struct _Unwind_Context *context, int index, _Unwind_Word val)

{

  int size;

  void *ptr;

  index = DWARF_REG_TO_UNWIND_COLUMN (index);

  gcc_assert (index < (int) sizeof(dwarf_reg_size_table));

  size = dwarf_reg_size_table[index];

  if (_Unwind_IsExtendedContext (context) && context->by_value[index])

    {

      context->reg[index] = _Unwind_Get_Unwind_Context_Reg_Val (val);

      return;

    }

  ptr = (void *) (_Unwind_Internal_Ptr) context->reg[index];

  if (size == sizeof(_Unwind_Ptr))

    * (_Unwind_Ptr *) ptr = val;

  else

    {

      gcc_assert (size == sizeof(_Unwind_Word));

      * (_Unwind_Word *) ptr = val;

    }

}

/* Get the pointer to a register INDEX as saved in CONTEXT.  */

static inline void *

_Unwind_GetGRPtr (struct _Unwind_Context *context, int index)

{

  index = DWARF_REG_TO_UNWIND_COLUMN (index);

  if (_Unwind_IsExtendedContext (context) && context->by_value[index])

    return &context->reg[index];

  return (void *) (_Unwind_Internal_Ptr) context->reg[index];

}

/* Set the pointer to a register INDEX as saved in CONTEXT.  */

static inline void

_Unwind_SetGRPtr (struct _Unwind_Context *context, int index, void *p)

{

  index = DWARF_REG_TO_UNWIND_COLUMN (index);

  if (_Unwind_IsExtendedContext (context))

    context->by_value[index] = 0;

  context->reg[index] = (_Unwind_Context_Reg_Val) (_Unwind_Internal_Ptr) p;

}

/* Overwrite the saved value for register INDEX in CONTEXT with VAL.  */

static inline void

_Unwind_SetGRValue (struct _Unwind_Context *context, int index,

		    _Unwind_Word val)

{

  index = DWARF_REG_TO_UNWIND_COLUMN (index);

  gcc_assert (index < (int) sizeof(dwarf_reg_size_table));

  /* Return column size may be smaller than _Unwind_Context_Reg_Val.  */

  gcc_assert (dwarf_reg_size_table[index] <= sizeof (_Unwind_Context_Reg_Val));

  context->by_value[index] = 1;

  context->reg[index] = _Unwind_Get_Unwind_Context_Reg_Val (val);

}

/* Return nonzero if register INDEX is stored by value rather than

   by reference.  */

static inline int

_Unwind_GRByValue (struct _Unwind_Context *context, int index)

{

  index = DWARF_REG_TO_UNWIND_COLUMN (index);

  return context->by_value[index];

}

/* Retrieve the return address for CONTEXT.  */

inline _Unwind_Ptr

_Unwind_GetIP (struct _Unwind_Context *context)

{

  return (_Unwind_Ptr) context->ra;

}

/* Retrieve the return address and flag whether that IP is before

   or after first not yet fully executed instruction.  */

inline _Unwind_Ptr

_Unwind_GetIPInfo (struct _Unwind_Context *context, int *ip_before_insn)

{

  *ip_before_insn = _Unwind_IsSignalFrame (context);

  return (_Unwind_Ptr) context->ra;

}

/* Overwrite the return address for CONTEXT with VAL.  */

inline void

_Unwind_SetIP (struct _Unwind_Context *context, _Unwind_Ptr val)

{

  context->ra = (void *) val;

}

void *

_Unwind_GetLanguageSpecificData (struct _Unwind_Context *context)

{

  return context->lsda;

}

_Unwind_Ptr

_Unwind_GetRegionStart (struct _Unwind_Context *context)

{

  return (_Unwind_Ptr) context->bases.func;

}

void *

_Unwind_FindEnclosingFunction (void *pc)

{

  struct dwarf_eh_bases bases;

  const struct dwarf_fde *fde = _Unwind_Find_FDE (pc-1, &bases);

  if (fde)

    return bases.func;

  else

    return NULL;

}

#ifndef __ia64__

_Unwind_Ptr

_Unwind_GetDataRelBase (struct _Unwind_Context *context)

{

  return (_Unwind_Ptr) context->bases.dbase;

}

_Unwind_Ptr

_Unwind_GetTextRelBase (struct _Unwind_Context *context)

{

  return (_Unwind_Ptr) context->bases.tbase;

}

#endif

#ifdef MD_UNWIND_SUPPORT

#include MD_UNWIND_SUPPORT

#endif

/* Extract any interesting information from the CIE for the translation

   unit F belongs to.  Return a pointer to the byte after the augmentation,

   or NULL if we encountered an undecipherable augmentation.  */

static const unsigned char *

extract_cie_info (const struct dwarf_cie *cie, struct _Unwind_Context *context,

		  _Unwind_FrameState *fs)

{

  const unsigned char *aug = cie->augmentation;

  const unsigned char *p = aug + strlen ((const char *)aug) + 1;

  const unsigned char *ret = NULL;

  _uleb128_t utmp;

  _sleb128_t stmp;

  /* g++ v2 "eh" has pointer immediately following augmentation string,

     so it must be handled first.  */

  if (aug[0] == 'e' && aug[1] == 'h')

    {

      fs->eh_ptr = read_pointer (p);

      p += sizeof (void *);

      aug += 2;

    }

  /* After the augmentation resp. pointer for "eh" augmentation

     follows for CIE version >= 4 address size byte and

     segment size byte.  */

  if (__builtin_expect (cie->version >= 4, 0))

    {

      if (p[0] != sizeof (void *) || p[1] != 0)

	return NULL;

      p += 2;

    }

  /* Immediately following this are the code and

     data alignment and return address column.  */

  p = read_uleb128 (p, &utmp);

  fs->code_align = (_Unwind_Word)utmp;

  p = read_sleb128 (p, &stmp);

  fs->data_align = (_Unwind_Sword)stmp;

  if (cie->version == 1)

    fs->retaddr_column = *p++;

  else

    {

      p = read_uleb128 (p, &utmp);

      fs->retaddr_column = (_Unwind_Word)utmp;

    }

  fs->lsda_encoding = DW_EH_PE_omit;

  /* If the augmentation starts with 'z', then a uleb128 immediately

     follows containing the length of the augmentation field following

     the size.  */

  if (*aug == 'z')

    {

      p = read_uleb128 (p, &utmp);

      ret = p + utmp;

      fs->saw_z = 1;

      ++aug;

    }

  /* Iterate over recognized augmentation subsequences.  */

  while (*aug != '\0')

    {

      /* "L" indicates a byte showing how the LSDA pointer is encoded.  */

      if (aug[0] == 'L')

	{

	  fs->lsda_encoding = *p++;

	  aug += 1;

	}

      /* "R" indicates a byte indicating how FDE addresses are encoded.  */

      else if (aug[0] == 'R')

	{

	  fs->fde_encoding = *p++;

	  aug += 1;

	}

      /* "P" indicates a personality routine in the CIE augmentation.  */

      else if (aug[0] == 'P')

	{

	  _Unwind_Ptr personality;

	  p = read_encoded_value (context, *p, p + 1, &personality);

	  fs->personality = (_Unwind_Personality_Fn) personality;

	  aug += 1;

	}

      /* "S" indicates a signal frame.  */

      else if (aug[0] == 'S')

	{

	  fs->signal_frame = 1;

	  aug += 1;

	}

      /* Otherwise we have an unknown augmentation string.

	 Bail unless we saw a 'z' prefix.  */

      else

	return ret;

    }

  return ret ? ret : p;

}

/* Decode a DW_OP stack program.  Return the top of stack.  Push INITIAL

   onto the stack to start.  */

static _Unwind_Word

execute_stack_op (const unsigned char *op_ptr, const unsigned char *op_end,

		  struct _Unwind_Context *context, _Unwind_Word initial)

{

  _Unwind_Word stack[64];	/* ??? Assume this is enough.  */

  int stack_elt;

  stack[0] = initial;

  stack_elt = 1;

  while (op_ptr < op_end)

    {

      enum dwarf_location_atom op = *op_ptr++;

      _Unwind_Word result;

      _uleb128_t reg, utmp;

      _sleb128_t offset, stmp;

      switch (op)

	{

	case DW_OP_lit0:

	case DW_OP_lit1:

	case DW_OP_lit2:

	case DW_OP_lit3:

	case DW_OP_lit4:

	case DW_OP_lit5:

	case DW_OP_lit6:

	case DW_OP_lit7:

	case DW_OP_lit8:

	case DW_OP_lit9:

	case DW_OP_lit10:

	case DW_OP_lit11:

	case DW_OP_lit12:

	case DW_OP_lit13:

	case DW_OP_lit14:

	case DW_OP_lit15:

	case DW_OP_lit16:

	case DW_OP_lit17:

	case DW_OP_lit18:

	case DW_OP_lit19:

	case DW_OP_lit20:

	case DW_OP_lit21:

	case DW_OP_lit22:

	case DW_OP_lit23:

	case DW_OP_lit24:

	case DW_OP_lit25:

	case DW_OP_lit26:

	case DW_OP_lit27:

	case DW_OP_lit28:

	case DW_OP_lit29:

	case DW_OP_lit30:

	case DW_OP_lit31:

	  result = op - DW_OP_lit0;

	  break;

	case DW_OP_addr:

	  result = (_Unwind_Word) (_Unwind_Ptr) read_pointer (op_ptr);

	  op_ptr += sizeof (void *);

	  break;

	case DW_OP_GNU_encoded_addr:

	  {

	    _Unwind_Ptr presult;

	    op_ptr = read_encoded_value (context, *op_ptr, op_ptr+1, &presult);

	    result = presult;

	  }

	  break;

	case DW_OP_const1u:

	  result = read_1u (op_ptr);

	  op_ptr += 1;

	  break;

	case DW_OP_const1s:

	  result = read_1s (op_ptr);

	  op_ptr += 1;

	  break;

	case DW_OP_const2u:

	  result = read_2u (op_ptr);

	  op_ptr += 2;

	  break;

	case DW_OP_const2s:

	  result = read_2s (op_ptr);

	  op_ptr += 2;

	  break;

	case DW_OP_const4u:

	  result = read_4u (op_ptr);

	  op_ptr += 4;

	  break;

	case DW_OP_const4s:

	  result = read_4s (op_ptr);

	  op_ptr += 4;

	  break;

	case DW_OP_const8u:

	  result = read_8u (op_ptr);

	  op_ptr += 8;

	  break;

	case DW_OP_const8s:

	  result = read_8s (op_ptr);

	  op_ptr += 8;

	  break;

	case DW_OP_constu:

	  op_ptr = read_uleb128 (op_ptr, &utmp);

	  result = (_Unwind_Word)utmp;

	  break;

	case DW_OP_consts:

	  op_ptr = read_sleb128 (op_ptr, &stmp);

	  result = (_Unwind_Sword)stmp;

	  break;

	case DW_OP_reg0:

	case DW_OP_reg1:

	case DW_OP_reg2:

	case DW_OP_reg3:

	case DW_OP_reg4:

	case DW_OP_reg5:

	case DW_OP_reg6:

	case DW_OP_reg7:

	case DW_OP_reg8:

	case DW_OP_reg9:

	case DW_OP_reg10:

	case DW_OP_reg11:

	case DW_OP_reg12:

	case DW_OP_reg13:

	case DW_OP_reg14:

	case DW_OP_reg15:

	case DW_OP_reg16:

	case DW_OP_reg17:

	case DW_OP_reg18:

	case DW_OP_reg19:

	case DW_OP_reg20:

	case DW_OP_reg21:

	case DW_OP_reg22:

	case DW_OP_reg23:

	case DW_OP_reg24:

	case DW_OP_reg25:

	case DW_OP_reg26:

	case DW_OP_reg27:

	case DW_OP_reg28:

	case DW_OP_reg29:

	case DW_OP_reg30:

	case DW_OP_reg31:

	  result = _Unwind_GetGR (context, op - DW_OP_reg0);

	  break;

	case DW_OP_regx:

	  op_ptr = read_uleb128 (op_ptr, ®);

	  result = _Unwind_GetGR (context, reg);

	  break;

	case DW_OP_breg0:

	case DW_OP_breg1:

	case DW_OP_breg2:

	case DW_OP_breg3:

	case DW_OP_breg4:

	case DW_OP_breg5:

	case DW_OP_breg6:

	case DW_OP_breg7:

	case DW_OP_breg8:

	case DW_OP_breg9:

	case DW_OP_breg10:

	case DW_OP_breg11:

	case DW_OP_breg12:

	case DW_OP_breg13:

	case DW_OP_breg14:

	case DW_OP_breg15:

	case DW_OP_breg16:

	case DW_OP_breg17:

	case DW_OP_breg18:

	case DW_OP_breg19:

	case DW_OP_breg20:

	case DW_OP_breg21:

	case DW_OP_breg22:

	case DW_OP_breg23:

	case DW_OP_breg24:

	case DW_OP_breg25:

	case DW_OP_breg26:

	case DW_OP_breg27:

	case DW_OP_breg28:

	case DW_OP_breg29:

	case DW_OP_breg30:

	case DW_OP_breg31:

	  op_ptr = read_sleb128 (op_ptr, &offset);

	  result = _Unwind_GetGR (context, op - DW_OP_breg0) + offset;

	  break;

	case DW_OP_bregx:

	  op_ptr = read_uleb128 (op_ptr, ®);

	  op_ptr = read_sleb128 (op_ptr, &offset);

	  result = _Unwind_GetGR (context, reg) + (_Unwind_Word)offset;

	  break;

	case DW_OP_dup:

	  gcc_assert (stack_elt);

	  result = stack[stack_elt - 1];

	  break;

	case DW_OP_drop:

	  gcc_assert (stack_elt);

	  stack_elt -= 1;

	  goto no_push;

	case DW_OP_pick:

	  offset = *op_ptr++;

	  gcc_assert (offset < stack_elt - 1);

	  result = stack[stack_elt - 1 - offset];

	  break;

	case DW_OP_over:

	  gcc_assert (stack_elt >= 2);

	  result = stack[stack_elt - 2];

	  break;

	case DW_OP_swap:

	  {

	    _Unwind_Word t;

	    gcc_assert (stack_elt >= 2);

	    t = stack[stack_elt - 1];

	    stack[stack_elt - 1] = stack[stack_elt - 2];

	    stack[stack_elt - 2] = t;

	    goto no_push;

	  }

	case DW_OP_rot:

	  {

	    _Unwind_Word t1, t2, t3;

	    gcc_assert (stack_elt >= 3);

	    t1 = stack[stack_elt - 1];

	    t2 = stack[stack_elt - 2];

	    t3 = stack[stack_elt - 3];

	    stack[stack_elt - 1] = t2;

	    stack[stack_elt - 2] = t3;

	    stack[stack_elt - 3] = t1;

	    goto no_push;

	  }

	case DW_OP_deref:

	case DW_OP_deref_size:

	case DW_OP_abs:

	case DW_OP_neg:

	case DW_OP_not:

	case DW_OP_plus_uconst:

	  /* Unary operations.  */

	  gcc_assert (stack_elt);

	  stack_elt -= 1;

	  result = stack[stack_elt];

	  switch (op)

	    {

	    case DW_OP_deref:

	      {

		void *ptr = (void *) (_Unwind_Ptr) result;

		result = (_Unwind_Ptr) read_pointer (ptr);

	      }

	      break;

	    case DW_OP_deref_size:

	      {

		void *ptr = (void *) (_Unwind_Ptr) result;

		switch (*op_ptr++)

		  {

		  case 1:

		    result = read_1u (ptr);

		    break;

		  case 2:

		    result = read_2u (ptr);

		    break;

		  case 4:

		    result = read_4u (ptr);

		    break;

		  case 8:

		    result = read_8u (ptr);

		    break;

		  default:

		    gcc_unreachable ();

		  }

	      }

	      break;

	    case DW_OP_abs:

	      if ((_Unwind_Sword) result < 0)

		result = -result;

	      break;

	    case DW_OP_neg:

	      result = -result;

	      break;

	    case DW_OP_not:

	      result = ~result;

	      break;

	    case DW_OP_plus_uconst:

	      op_ptr = read_uleb128 (op_ptr, &utmp);

	      result += (_Unwind_Word)utmp;

	      break;

	    default:

	      gcc_unreachable ();

	    }

	  break;

	case DW_OP_and:

	case DW_OP_div:

	case DW_OP_minus:

	case DW_OP_mod:

	case DW_OP_mul:

	case DW_OP_or:

	case DW_OP_plus:

	case DW_OP_shl:

	case DW_OP_shr:

	case DW_OP_shra:

	case DW_OP_xor:

	case DW_OP_le:

	case DW_OP_ge:

	case DW_OP_eq:

	case DW_OP_lt:

	case DW_OP_gt:

	case DW_OP_ne:

	  {

	    /* Binary operations.  */

	    _Unwind_Word first, second;

	    gcc_assert (stack_elt >= 2);

	    stack_elt -= 2;

	    second = stack[stack_elt];

	    first = stack[stack_elt + 1];

	    switch (op)

	      {

	      case DW_OP_and:

		result = second & first;

		break;

	      case DW_OP_div:

		result = (_Unwind_Sword) second / (_Unwind_Sword) first;

		break;

	      case DW_OP_minus:

		result = second - first;

		break;

	      case DW_OP_mod:

		result = second % first;

		break;

	      case DW_OP_mul:

		result = second * first;

		break;

	      case DW_OP_or:

		result = second | first;

		break;

	      case DW_OP_plus:

		result = second + first;

		break;

	      case DW_OP_shl:

		result = second << first;

		break;

	      case DW_OP_shr:

		result = second >> first;

		break;

	      case DW_OP_shra:

		result = (_Unwind_Sword) second >> first;

		break;

	      case DW_OP_xor:

		result = second ^ first;

		break;

	      case DW_OP_le:

		result = (_Unwind_Sword) second <= (_Unwind_Sword) first;

		break;

	      case DW_OP_ge:

		result = (_Unwind_Sword) second >= (_Unwind_Sword) first;

		break;

	      case DW_OP_eq:

		result = (_Unwind_Sword) second == (_Unwind_Sword) first;

		break;

	      case DW_OP_lt:

		result = (_Unwind_Sword) second < (_Unwind_Sword) first;

		break;

	      case DW_OP_gt:

		result = (_Unwind_Sword) second > (_Unwind_Sword) first;

		break;

	      case DW_OP_ne:

		result = (_Unwind_Sword) second != (_Unwind_Sword) first;

		break;

	      default:

		gcc_unreachable ();

	      }

	  }

	  break;

	case DW_OP_skip:

	  offset = read_2s (op_ptr);

	  op_ptr += 2;

	  op_ptr += offset;

	  goto no_push;

	case DW_OP_bra:

	  gcc_assert (stack_elt);

	  stack_elt -= 1;

	  offset = read_2s (op_ptr);

	  op_ptr += 2;

	  if (stack[stack_elt] != 0)

	    op_ptr += offset;

	  goto no_push;

	case DW_OP_nop:

	  goto no_push;

	default:

	  gcc_unreachable ();

	}

      /* Most things push a result value.  */

      gcc_assert ((size_t) stack_elt < sizeof(stack)/sizeof(*stack));

      stack[stack_elt++] = result;

    no_push:;

    }

  /* We were executing this program to get a value.  It should be

     at top of stack.  */

  gcc_assert (stack_elt);

  stack_elt -= 1;

  return stack[stack_elt];

}

/* Decode DWARF 2 call frame information. Takes pointers the

   instruction sequence to decode, current register information and

   CIE info, and the PC range to evaluate.  */

static void

execute_cfa_program (const unsigned char *insn_ptr,

		     const unsigned char *insn_end,

		     struct _Unwind_Context *context,

		     _Unwind_FrameState *fs)

{

  struct frame_state_reg_info *unused_rs = NULL;

  /* Don't allow remember/restore between CIE and FDE programs.  */

  fs->regs.prev = NULL;

  /* The comparison with the return address uses < rather than <= because

     we are only interested in the effects of code before the call; for a

     noreturn function, the return address may point to unrelated code with

     a different stack configuration that we are not interested in.  We

     assume that the call itself is unwind info-neutral; if not, or if

     there are delay instructions that adjust the stack, these must be

     reflected at the point immediately before the call insn.

     In signal frames, return address is after last completed instruction,

     so we add 1 to return address to make the comparison <=.  */

  while (insn_ptr < insn_end

	 && fs->pc < context->ra + _Unwind_IsSignalFrame (context))

    {

      unsigned char insn = *insn_ptr++;

      _uleb128_t reg, utmp;

      _sleb128_t offset, stmp;

      if ((insn & 0xc0) == DW_CFA_advance_loc)

	fs->pc += (insn & 0x3f) * fs->code_align;

      else if ((insn & 0xc0) == DW_CFA_offset)

	{

	  reg = insn & 0x3f;

	  insn_ptr = read_uleb128 (insn_ptr, &utmp);

	  offset = (_Unwind_Sword) utmp * fs->data_align;

	  reg = DWARF_REG_TO_UNWIND_COLUMN (reg);

	  if (UNWIND_COLUMN_IN_RANGE (reg))

	    {

	      fs->regs.reg[reg].how = REG_SAVED_OFFSET;

	      fs->regs.reg[reg].loc.offset = offset;

	    }

	}

      else if ((insn & 0xc0) == DW_CFA_restore)

	{

	  reg = insn & 0x3f;

	  reg = DWARF_REG_TO_UNWIND_COLUMN (reg);

	  if (UNWIND_COLUMN_IN_RANGE (reg))

	    fs->regs.reg[reg].how = REG_UNSAVED;

	}

      else switch (insn)

	{

	case DW_CFA_set_loc:

	  {

	    _Unwind_Ptr pc;

	    insn_ptr = read_encoded_value (context, fs->fde_encoding,

					   insn_ptr, &pc);

	    fs->pc = (void *) pc;

	  }

	  break;

	case DW_CFA_advance_loc1:

	  fs->pc += read_1u (insn_ptr) * fs->code_align;

	  insn_ptr += 1;

	  break;

	case DW_CFA_advance_loc2:

	  fs->pc += read_2u (insn_ptr) * fs->code_align;

	  insn_ptr += 2;

	  break;

	case DW_CFA_advance_loc4:

	  fs->pc += read_4u (insn_ptr) * fs->code_align;

	  insn_ptr += 4;

	  break;

	case DW_CFA_offset_extended:

	  insn_ptr = read_uleb128 (insn_ptr, ®);

	  insn_ptr = read_uleb128 (insn_ptr, &utmp);

	  offset = (_Unwind_Sword) utmp * fs->data_align;

	  reg = DWARF_REG_TO_UNWIND_COLUMN (reg);

	  if (UNWIND_COLUMN_IN_RANGE (reg))

	    {

	      fs->regs.reg[reg].how = REG_SAVED_OFFSET;

	      fs->regs.reg[reg].loc.offset = offset;

	    }

	  break;

	case DW_CFA_restore_extended:

	  insn_ptr = read_uleb128 (insn_ptr, ®);

	  /* FIXME, this is wrong; the CIE might have said that the

	     register was saved somewhere.  */

	  reg = DWARF_REG_TO_UNWIND_COLUMN (reg);

	  if (UNWIND_COLUMN_IN_RANGE (reg))

	    fs->regs.reg[reg].how = REG_UNSAVED;

	  break;

	case DW_CFA_same_value:

	  insn_ptr = read_uleb128 (insn_ptr, ®);

	  reg = DWARF_REG_TO_UNWIND_COLUMN (reg);

	  if (UNWIND_COLUMN_IN_RANGE (reg))

	    fs->regs.reg[reg].how = REG_UNSAVED;

	  break;

	case DW_CFA_undefined:

	  insn_ptr = read_uleb128 (insn_ptr, ®);

	  reg = DWARF_REG_TO_UNWIND_COLUMN (reg);

	  if (UNWIND_COLUMN_IN_RANGE (reg))

	    fs->regs.reg[reg].how = REG_UNDEFINED;

	  break;

	case DW_CFA_nop:

	  break;

	case DW_CFA_register:

	  {

	    _uleb128_t reg2;

	    insn_ptr = read_uleb128 (insn_ptr, ®);

	    insn_ptr = read_uleb128 (insn_ptr, ®2);

	    reg = DWARF_REG_TO_UNWIND_COLUMN (reg);

	    if (UNWIND_COLUMN_IN_RANGE (reg))

	      {

	        fs->regs.reg[reg].how = REG_SAVED_REG;

	        fs->regs.reg[reg].loc.reg = (_Unwind_Word)reg2;

	      }

	  }

	  break;

	case DW_CFA_remember_state:

	  {

	    struct frame_state_reg_info *new_rs;

	    if (unused_rs)

	      {

		new_rs = unused_rs;

		unused_rs = unused_rs->prev;

	      }

	    else

	      new_rs = alloca (sizeof (struct frame_state_reg_info));

	    *new_rs = fs->regs;

	    fs->regs.prev = new_rs;

	  }

	  break;

	case DW_CFA_restore_state:

	  {

	    struct frame_state_reg_info *old_rs = fs->regs.prev;

	    fs->regs = *old_rs;

	    old_rs->prev = unused_rs;

	    unused_rs = old_rs;

	  }

	  break;

	case DW_CFA_def_cfa:

	  insn_ptr = read_uleb128 (insn_ptr, &utmp);

	  fs->regs.cfa_reg = (_Unwind_Word)utmp;

	  insn_ptr = read_uleb128 (insn_ptr, &utmp);

	  fs->regs.cfa_offset = (_Unwind_Word)utmp;

	  fs->regs.cfa_how = CFA_REG_OFFSET;

	  break;

	case DW_CFA_def_cfa_register:

	  insn_ptr = read_uleb128 (insn_ptr, &utmp);

	  fs->regs.cfa_reg = (_Unwind_Word)utmp;

	  fs->regs.cfa_how = CFA_REG_OFFSET;

	  break;

	case DW_CFA_def_cfa_offset:

	  insn_ptr = read_uleb128 (insn_ptr, &utmp);

	  fs->regs.cfa_offset = utmp;

	  /* cfa_how deliberately not set.  */

	  break;

	case DW_CFA_def_cfa_expression:

	  fs->regs.cfa_exp = insn_ptr;

	  fs->regs.cfa_how = CFA_EXP;

	  insn_ptr = read_uleb128 (insn_ptr, &utmp);

	  insn_ptr += utmp;

	  break;

	case DW_CFA_expression:

	  insn_ptr = read_uleb128 (insn_ptr, ®);

	  reg = DWARF_REG_TO_UNWIND_COLUMN (reg);

	  if (UNWIND_COLUMN_IN_RANGE (reg))

	    {

	      fs->regs.reg[reg].how = REG_SAVED_EXP;

	      fs->regs.reg[reg].loc.exp = insn_ptr;

	    }

	  insn_ptr = read_uleb128 (insn_ptr, &utmp);

	  insn_ptr += utmp;

	  break;