libgcc/config/arm/pr-support.c - rust-lang/gcc - Git at Google

 /* ARM EABI compliant unwinding routines
    Copyright (C) 2004-2021 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/>.  */

 #pragma GCC target ("general-regs-only")
 #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)  /* Obsolete FPA.  */
 	    return _URC_FAILURE;

 	  /* 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)
 	    {
               /* 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;
 	    }
 	  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 ();
 }
	/* ARM EABI compliant unwinding routines
	Copyright (C) 2004-2021 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/>. */

	#pragma GCC target ("general-regs-only")
	#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) /* Obsolete FPA. */
	return _URC_FAILURE;

	/* 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)
	{
	/* 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;
	}
	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 ();
	}