/* DWARF2 EH unwinding support for AIX.
   Copyright (C) 2011 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/>.  */

/* If the current unwind info (FS) does not contain explicit info
   saving R2, then we have to do a minor amount of code reading to
   figure out if it was saved.  The big problem here is that the
   code that does the save/restore is generated by the linker, so
   we have no good way to determine at compile time what to do.  */

#define R_LR 65

#ifdef __64BIT__
#define MD_FROB_UPDATE_CONTEXT(CTX, FS)					\
  do {									\
    if ((FS)->regs.reg[2].how == REG_UNSAVED)				\
      {									\
	unsigned int *insn						\
	  = (unsigned int *)						\
	    _Unwind_GetGR ((CTX), R_LR);				\
	if (*insn == 0xE8410028)					\
	  _Unwind_SetGRPtr ((CTX), 2, (CTX)->cfa + 40);			\
      }									\
  } while (0)
#else
#define MD_FROB_UPDATE_CONTEXT(CTX, FS)					\
  do {									\
    if ((FS)->regs.reg[2].how == REG_UNSAVED)				\
      {									\
	unsigned int *insn						\
	  = (unsigned int *)						\
	    _Unwind_GetGR ((CTX), R_LR);				\
	if (*insn == 0x80410014)					\
	  _Unwind_SetGRPtr ((CTX), 2, (CTX)->cfa + 20);			\
      }									\
  } while (0)
#endif