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/* DWARF2 EH unwinding support for SPARC Linux.

   Copyright 2004, 2005, 2009 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

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

/* Do code reading to identify a signal frame, and set the frame

   state data appropriately.  See unwind-dw2.c for the structs.  */

#if defined(__arch64__)

/* 64-bit SPARC version */

#define MD_FALLBACK_FRAME_STATE_FOR sparc64_fallback_frame_state

static _Unwind_Reason_Code

sparc64_fallback_frame_state (struct _Unwind_Context *context,

                              _Unwind_FrameState *fs)

{

  unsigned int *pc = context->ra;

  long this_cfa = (long) context->cfa;

  long new_cfa, ra_location, shifted_ra_location;

  long regs_off, fpu_save_off;

  long fpu_save;

  int i;

  if (pc[0] != 0x82102065        /* mov NR_rt_sigreturn, %g1 */

      || pc[1] != 0x91d0206d)   /* ta 0x6d */

    return _URC_END_OF_STACK;

  regs_off = 192 + 128;

  fpu_save_off = regs_off + (16 * 8) + (3 * 8) + (2 * 4);

  new_cfa = *(long *)(this_cfa + regs_off + (14 * 8));

  new_cfa += 2047; /* Stack bias */

  fpu_save = *(long *)(this_cfa + fpu_save_off);

  fs->regs.cfa_how = CFA_REG_OFFSET;

  fs->regs.cfa_reg = __builtin_dwarf_sp_column ();

  fs->regs.cfa_offset = new_cfa - this_cfa;

  for (i = 1; i < 16; i++)

    {

      /* We never restore %sp as everything is purely CFA-based.  */

      if ((unsigned int) i == __builtin_dwarf_sp_column ())

        continue;

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

      fs->regs.reg[i].loc.offset

        = this_cfa + regs_off + (i * 8) - new_cfa;

    }

  for (i = 0; i < 16; i++)

    {

      fs->regs.reg[i + 16].how = REG_SAVED_OFFSET;

      fs->regs.reg[i + 16].loc.offset

        = this_cfa + (i * 8) - new_cfa;

    }

  if (fpu_save)

    {

      for (i = 0; i < 64; i++)

        {

          if (i > 32 && (i & 0x1))

            continue;

          fs->regs.reg[i + 32].how = REG_SAVED_OFFSET;

          fs->regs.reg[i + 32].loc.offset

            = fpu_save + (i * 4) - new_cfa;

        }

    }

  /* State the rules to find the kernel's code "return address", which is

     the address of the active instruction when the signal was caught.

     On the SPARC, since RETURN_ADDR_OFFSET (essentially 8) is defined, we

     need to preventively subtract it from the purported return address.  */

  ra_location = this_cfa + regs_off + 17 * 8;

  shifted_ra_location = this_cfa + regs_off + 19 * 8; /* Y register */

  *(long *)shifted_ra_location = *(long *)ra_location - 8;

  fs->retaddr_column = 0;

  fs->regs.reg[0].how = REG_SAVED_OFFSET;

  fs->regs.reg[0].loc.offset = shifted_ra_location - new_cfa;

  fs->signal_frame = 1;

  return _URC_NO_REASON;

}

#define MD_FROB_UPDATE_CONTEXT sparc64_frob_update_context

static void

sparc64_frob_update_context (struct _Unwind_Context *context,

                             _Unwind_FrameState *fs)

{

  /* The column of %sp contains the old CFA, not the old value of %sp.

     The CFA offset already comprises the stack bias so, when %sp is the

     CFA register, we must avoid counting the stack bias twice.  Do not

     do that for signal frames as the offset is artificial for them.  */

  if (fs->regs.cfa_reg == __builtin_dwarf_sp_column ()

      && fs->regs.cfa_how == CFA_REG_OFFSET

      && fs->regs.cfa_offset != 0

      && !fs->signal_frame)

    context->cfa -= 2047;

}

#else

/* 32-bit SPARC version */

#define MD_FALLBACK_FRAME_STATE_FOR sparc_fallback_frame_state

static _Unwind_Reason_Code

sparc_fallback_frame_state (struct _Unwind_Context *context,

                            _Unwind_FrameState *fs)

{

  unsigned int *pc = context->ra;

  int this_cfa = (int) context->cfa;

  int new_cfa, ra_location, shifted_ra_location;

  int regs_off, fpu_save_off;

  int fpu_save;

  int old_style, i;

  if (pc[1] != 0x91d02010)      /* ta 0x10 */

    return _URC_END_OF_STACK;

  if (pc[0] == 0x821020d8)       /* mov NR_sigreturn, %g1 */

    old_style = 1;

  else if (pc[0] == 0x82102065)  /* mov NR_rt_sigreturn, %g1 */

    old_style = 0;

  else

    return _URC_END_OF_STACK;

  if (old_style)

    {

      regs_off = 96;

      fpu_save_off = regs_off + (4 * 4) + (16 * 4);

    }

  else

    {

      regs_off = 96 + 128;

      fpu_save_off = regs_off + (4 * 4) + (16 * 4) + (2 * 4);

    }

  new_cfa = *(int *)(this_cfa + regs_off + (4 * 4) + (14 * 4));

  fpu_save = *(int *)(this_cfa + fpu_save_off);

  fs->regs.cfa_how = CFA_REG_OFFSET;

  fs->regs.cfa_reg = __builtin_dwarf_sp_column ();

  fs->regs.cfa_offset = new_cfa - this_cfa;

  for (i = 1; i < 16; i++)

    {

      /* We never restore %sp as everything is purely CFA-based.  */

      if ((unsigned int) i == __builtin_dwarf_sp_column ())

        continue;

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

      fs->regs.reg[i].loc.offset

        = this_cfa + regs_off + (4 * 4) + (i * 4) - new_cfa;

    }

  for (i = 0; i < 16; i++)

    {

      fs->regs.reg[i + 16].how = REG_SAVED_OFFSET;

      fs->regs.reg[i + 16].loc.offset

        = this_cfa + (i * 4) - new_cfa;

    }

  if (fpu_save)

    {

      for (i = 0; i < 32; i++)

        {

          fs->regs.reg[i + 32].how = REG_SAVED_OFFSET;

          fs->regs.reg[i + 32].loc.offset

            = fpu_save + (i * 4) - new_cfa;

        }

    }

  /* State the rules to find the kernel's code "return address", which is

     the address of the active instruction when the signal was caught.

     On the SPARC, since RETURN_ADDR_OFFSET (essentially 8) is defined, we

     need to preventively subtract it from the purported return address.  */

  ra_location = this_cfa + regs_off + 4;

  shifted_ra_location = this_cfa + regs_off + 3 * 4; /* Y register */

  *(int *)shifted_ra_location = *(int *)ra_location - 8;

  fs->retaddr_column = 0;

  fs->regs.reg[0].how = REG_SAVED_OFFSET;

  fs->regs.reg[0].loc.offset = shifted_ra_location - new_cfa;

  fs->signal_frame = 1;

  return _URC_NO_REASON;

}

#endif