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/* ARM EABI compliant unwinding routines

   Copyright (C) 2004, 2005, 2009 Free Software Foundation, Inc.

   Contributed by Paul Brook

   This file 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.

   This file 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

   <http://www.gnu.org/licenses/>.  */

#include "unwind.h"

/* We add a prototype for abort here to avoid creating a dependency on

   target headers.  */

extern void abort (void);

typedef struct _ZSt9type_info type_info; /* This names C++ type_info type */

/* Misc constants.  */

#define R_IP    12

#define R_SP    13

#define R_LR    14

#define R_PC    15

#define uint32_highbit (((_uw) 1) << 31)

void __attribute__((weak)) __cxa_call_unexpected(_Unwind_Control_Block *ucbp);

/* Unwind descriptors.  */

typedef struct

{

  _uw16 length;

  _uw16 offset;

} EHT16;

typedef struct

{

  _uw length;

  _uw offset;

} EHT32;

/* Calculate the address encoded by a 31-bit self-relative offset at address

   P.  Copy of routine in unwind-arm.c.  */

static inline _uw

selfrel_offset31 (const _uw *p)

{

  _uw offset;

  offset = *p;

  /* Sign extend to 32 bits.  */

  if (offset & (1 << 30))

    offset |= 1u << 31;

  return offset + (_uw) p;

}

/* Personality routine helper functions.  */

#define CODE_FINISH (0xb0)

/* Return the next byte of unwinding information, or CODE_FINISH if there is

   no data remaining.  */

static inline _uw8

next_unwind_byte (__gnu_unwind_state * uws)

{

  _uw8 b;

  if (uws->bytes_left == 0)

    {

      /* Load another word */

      if (uws->words_left == 0)

        return CODE_FINISH; /* Nothing left.  */

      uws->words_left--;

      uws->data = *(uws->next++);

      uws->bytes_left = 3;

    }

  else

    uws->bytes_left--;

  /* Extract the most significant byte.  */

  b = (uws->data >> 24) & 0xff;

  uws->data <<= 8;

  return b;

}

/* Execute the unwinding instructions described by UWS.  */

_Unwind_Reason_Code

__gnu_unwind_execute (_Unwind_Context * context, __gnu_unwind_state * uws)

{

  _uw op;

  int set_pc;

  _uw reg;

  set_pc = 0;

  for (;;)

    {

      op = next_unwind_byte (uws);

      if (op == CODE_FINISH)

        {

          /* If we haven't already set pc then copy it from lr.  */

          if (!set_pc)

            {

              _Unwind_VRS_Get (context, _UVRSC_CORE, R_LR, _UVRSD_UINT32,

                               &reg);

              _Unwind_VRS_Set (context, _UVRSC_CORE, R_PC, _UVRSD_UINT32,

                               &reg);

              set_pc = 1;

            }

          /* Drop out of the loop.  */

          break;

        }

      if ((op & 0x80) == 0)

        {

          /* vsp = vsp +- (imm6 << 2 + 4).  */

          _uw offset;

          offset = ((op & 0x3f) << 2) + 4;

          _Unwind_VRS_Get (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, &reg);

          if (op & 0x40)

            reg -= offset;

          else

            reg += offset;

          _Unwind_VRS_Set (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, &reg);

          continue;

        }

      if ((op & 0xf0) == 0x80)

        {

          op = (op << 8) | next_unwind_byte (uws);

          if (op == 0x8000)

            {

              /* Refuse to unwind.  */

              return _URC_FAILURE;

            }

          /* Pop r4-r15 under mask.  */

          op = (op << 4) & 0xfff0;

          if (_Unwind_VRS_Pop (context, _UVRSC_CORE, op, _UVRSD_UINT32)

              != _UVRSR_OK)

            return _URC_FAILURE;

          if (op & (1 << R_PC))

            set_pc = 1;

          continue;

        }

      if ((op & 0xf0) == 0x90)

        {

          op &= 0xf;

          if (op == 13 || op == 15)

            /* Reserved.  */

            return _URC_FAILURE;

          /* vsp = r[nnnn].  */

          _Unwind_VRS_Get (context, _UVRSC_CORE, op, _UVRSD_UINT32, &reg);

          _Unwind_VRS_Set (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, &reg);

          continue;

        }

      if ((op & 0xf0) == 0xa0)

        {

          /* Pop r4-r[4+nnn], [lr].  */

          _uw mask;

          mask = (0xff0 >> (7 - (op & 7))) & 0xff0;

          if (op & 8)

            mask |= (1 << R_LR);

          if (_Unwind_VRS_Pop (context, _UVRSC_CORE, mask, _UVRSD_UINT32)

              != _UVRSR_OK)

            return _URC_FAILURE;

          continue;

        }

      if ((op & 0xf0) == 0xb0)

        {

          /* op == 0xb0 already handled.  */

          if (op == 0xb1)

            {

              op = next_unwind_byte (uws);

              if (op == 0 || ((op & 0xf0) != 0))

                /* Spare.  */

                return _URC_FAILURE;

              /* Pop r0-r4 under mask.  */

              if (_Unwind_VRS_Pop (context, _UVRSC_CORE, op, _UVRSD_UINT32)

                  != _UVRSR_OK)

                return _URC_FAILURE;

              continue;

            }

          if (op == 0xb2)

            {

              /* vsp = vsp + 0x204 + (uleb128 << 2).  */

              int shift;

              _Unwind_VRS_Get (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32,

                               &reg);

              op = next_unwind_byte (uws);

              shift = 2;

              while (op & 0x80)

                {

                  reg += ((op & 0x7f) << shift);

                  shift += 7;

                  op = next_unwind_byte (uws);

                }

              reg += ((op & 0x7f) << shift) + 0x204;

              _Unwind_VRS_Set (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32,

                               &reg);

              continue;

            }

          if (op == 0xb3)

            {

              /* Pop VFP registers with fldmx.  */

              op = next_unwind_byte (uws);

              op = ((op & 0xf0) << 12) | ((op & 0xf) + 1);

              if (_Unwind_VRS_Pop (context, _UVRSC_VFP, op, _UVRSD_VFPX)

                  != _UVRSR_OK)

                return _URC_FAILURE;

              continue;

            }

          if ((op & 0xfc) == 0xb4)

            {

              /* Pop FPA E[4]-E[4+nn].  */

              op = 0x40000 | ((op & 3) + 1);

              if (_Unwind_VRS_Pop (context, _UVRSC_FPA, op, _UVRSD_FPAX)

                  != _UVRSR_OK)

                return _URC_FAILURE;

              continue;

            }

          /* op & 0xf8 == 0xb8.  */

          /* Pop VFP D[8]-D[8+nnn] with fldmx.  */

          op = 0x80000 | ((op & 7) + 1);

          if (_Unwind_VRS_Pop (context, _UVRSC_VFP, op, _UVRSD_VFPX)

              != _UVRSR_OK)

            return _URC_FAILURE;

          continue;

        }

      if ((op & 0xf0) == 0xc0)

        {

          if (op == 0xc6)

            {

              /* Pop iWMMXt D registers.  */

              op = next_unwind_byte (uws);

              op = ((op & 0xf0) << 12) | ((op & 0xf) + 1);

              if (_Unwind_VRS_Pop (context, _UVRSC_WMMXD, op, _UVRSD_UINT64)

                  != _UVRSR_OK)

                return _URC_FAILURE;

              continue;

            }

          if (op == 0xc7)

            {

              op = next_unwind_byte (uws);

              if (op == 0 || (op & 0xf0) != 0)

                /* Spare.  */

                return _URC_FAILURE;

              /* Pop iWMMXt wCGR{3,2,1,0} under mask.  */

              if (_Unwind_VRS_Pop (context, _UVRSC_WMMXC, op, _UVRSD_UINT32)

                  != _UVRSR_OK)

                return _URC_FAILURE;

              continue;

            }

          if ((op & 0xf8) == 0xc0)

            {

              /* Pop iWMMXt wR[10]-wR[10+nnn].  */

              op = 0xa0000 | ((op & 0xf) + 1);

              if (_Unwind_VRS_Pop (context, _UVRSC_WMMXD, op, _UVRSD_UINT64)

                  != _UVRSR_OK)

                return _URC_FAILURE;

              continue;

            }

          if (op == 0xc8)

            {

#ifndef __VFP_FP__

              /* Pop FPA registers.  */

              op = next_unwind_byte (uws);

              op = ((op & 0xf0) << 12) | ((op & 0xf) + 1);

              if (_Unwind_VRS_Pop (context, _UVRSC_FPA, op, _UVRSD_FPAX)

                  != _UVRSR_OK)

                return _URC_FAILURE;

              continue;

#else

              /* Pop VFPv3 registers D[16+ssss]-D[16+ssss+cccc] with vldm.  */

              op = next_unwind_byte (uws);

              op = (((op & 0xf0) + 16) << 12) | ((op & 0xf) + 1);

              if (_Unwind_VRS_Pop (context, _UVRSC_VFP, op, _UVRSD_DOUBLE)

                  != _UVRSR_OK)

                return _URC_FAILURE;

              continue;

#endif

            }

          if (op == 0xc9)

            {

              /* Pop VFP registers with fldmd.  */

              op = next_unwind_byte (uws);

              op = ((op & 0xf0) << 12) | ((op & 0xf) + 1);

              if (_Unwind_VRS_Pop (context, _UVRSC_VFP, op, _UVRSD_DOUBLE)

                  != _UVRSR_OK)

                return _URC_FAILURE;

              continue;

            }

          /* Spare.  */

          return _URC_FAILURE;

        }

      if ((op & 0xf8) == 0xd0)

        {

          /* Pop VFP D[8]-D[8+nnn] with fldmd.  */

          op = 0x80000 | ((op & 7) + 1);

          if (_Unwind_VRS_Pop (context, _UVRSC_VFP, op, _UVRSD_DOUBLE)

              != _UVRSR_OK)

            return _URC_FAILURE;

          continue;

        }

      /* Spare.  */

      return _URC_FAILURE;

    }

  return _URC_OK;

}

/* Execute the unwinding instructions associated with a frame.  UCBP and

   CONTEXT are the current exception object and virtual CPU state

   respectively.  */

_Unwind_Reason_Code

__gnu_unwind_frame (_Unwind_Control_Block * ucbp, _Unwind_Context * context)

{

  _uw *ptr;

  __gnu_unwind_state uws;

  ptr = (_uw *) ucbp->pr_cache.ehtp;

  /* Skip over the personality routine address.  */

  ptr++;

  /* Setup the unwinder state.  */

  uws.data = (*ptr) << 8;

  uws.next = ptr + 1;

  uws.bytes_left = 3;

  uws.words_left = ((*ptr) >> 24) & 0xff;

  return __gnu_unwind_execute (context, &uws);

}

/* Get the _Unwind_Control_Block from an _Unwind_Context.  */

static inline _Unwind_Control_Block *

unwind_UCB_from_context (_Unwind_Context * context)

{

  return (_Unwind_Control_Block *) _Unwind_GetGR (context, R_IP);

}

/* Get the start address of the function being unwound.  */

_Unwind_Ptr

_Unwind_GetRegionStart (_Unwind_Context * context)

{

  _Unwind_Control_Block *ucbp;

  ucbp = unwind_UCB_from_context (context);

  return (_Unwind_Ptr) ucbp->pr_cache.fnstart;

}

/* Find the Language specific exception data.  */

void *

_Unwind_GetLanguageSpecificData (_Unwind_Context * context)

{

  _Unwind_Control_Block *ucbp;

  _uw *ptr;

  /* Get a pointer to the exception table entry.  */

  ucbp = unwind_UCB_from_context (context);

  ptr = (_uw *) ucbp->pr_cache.ehtp;

  /* Skip the personality routine address.  */

  ptr++;

  /* Skip the unwind opcodes.  */

  ptr += (((*ptr) >> 24) & 0xff) + 1;

  return ptr;

}

/* These two should never be used.  */

_Unwind_Ptr

_Unwind_GetDataRelBase (_Unwind_Context *context __attribute__ ((unused)))

{

  abort ();

}

_Unwind_Ptr

_Unwind_GetTextRelBase (_Unwind_Context *context __attribute__ ((unused)))

{

  abort ();

}