linux-unwind.h (mips_fallback_frame_state): Rewrite return address calculation.

	* config/mips/linux-unwind.h (mips_fallback_frame_state): Rewrite
	return address calculation.  Substitute DWARF_ALT_FRAME_RETURN_COLUMN
	for SIGNAL_UNWIND_RETURN_COLUMN.
	* config/mips/mips.h (SIGNAL_UNWIND_RETURN_COLUMN): Remove.
	(DWARF_FRAME_REGNUM): Rewrite.
	(DWARF_ALT_FRAME_RETURN_COLUMN) Define.

From-SVN: r126555

gcc/ChangeLog

+2007-07-11  David Daney  <ddaney@avtrex.com>
+
+	* config/mips/linux-unwind.h (mips_fallback_frame_state): Rewrite
+	return address calculation.  Substitute DWARF_ALT_FRAME_RETURN_COLUMN
+	for SIGNAL_UNWIND_RETURN_COLUMN.
+	* config/mips/mips.h (SIGNAL_UNWIND_RETURN_COLUMN): Remove.
+	(DWARF_FRAME_REGNUM): Rewrite.
+	(DWARF_ALT_FRAME_RETURN_COLUMN) Define.
+
 2007-07-11  Nick Clifton  <nickc@redhat.com>
 
 	* config/m32r/m32r.h (INITIALIZE_TRAMPOLINE): Revert previous

gcc/config/mips/linux-unwind.h

 /* DWARF2 EH unwinding support for MIPS Linux.
-   Copyright (C) 2004, 2005, 2006 Free Software Foundation, Inc.
+   Copyright (C) 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
@@ -51,7 +51,6 @@ mips_fallback_frame_state (struct _Unwind_Context *context,
 			   _Unwind_FrameState *fs)
 {
   u_int32_t *pc = (u_int32_t *) context->ra;
-  u_int32_t t;
   struct sigcontext *sc;
   _Unwind_Ptr new_cfa;
   int i;
@@ -106,11 +105,10 @@ mips_fallback_frame_state (struct _Unwind_Context *context,
   /* The PC points to the faulting instruction, but the unwind tables
      expect it point to the following instruction.  We compensate by
      reporting a return address at the next instruction. */
-  fs->regs.reg[SIGNAL_UNWIND_RETURN_COLUMN].how = REG_SAVED_VAL_OFFSET;
-  t = (*(u_int32_t *)(void *)&sc->sc_pc) + 4;
-  fs->regs.reg[SIGNAL_UNWIND_RETURN_COLUMN].loc.offset
-    = (_Unwind_Ptr)t - new_cfa;
-  fs->retaddr_column = SIGNAL_UNWIND_RETURN_COLUMN;
+  fs->regs.reg[DWARF_ALT_FRAME_RETURN_COLUMN].how = REG_SAVED_VAL_OFFSET;
+  fs->regs.reg[DWARF_ALT_FRAME_RETURN_COLUMN].loc.offset
+    = (_Unwind_Ptr)(sc->sc_pc) + 4 - new_cfa;
+  fs->retaddr_column = DWARF_ALT_FRAME_RETURN_COLUMN;
 
   return _URC_NO_REASON;
 }

gcc/config/mips/mips.h

 /* Definitions of target machine for GNU compiler.  MIPS version.
    Copyright (C) 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998
-   1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+   1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007
+   Free Software Foundation, Inc.
    Contributed by A. Lichnewsky (lich@inria.inria.fr).
    Changed by Michael Meissner	(meissner@osf.org).
    64-bit r4000 support by Ian Lance Taylor (ian@cygnus.com) and
@@ -1007,15 +1008,12 @@ extern const struct mips_rtx_cost_data *mips_cost;
 #define DBX_REGISTER_NUMBER(REGNO) mips_dbx_regno[ (REGNO) ]
 
 /* The mapping from gcc register number to DWARF 2 CFA column number.  */
-#define DWARF_FRAME_REGNUM(REG)	(REG)
+#define DWARF_FRAME_REGNUM(REG) \
+  ((REG) == DWARF_ALT_FRAME_RETURN_COLUMN ? INVALID_REGNUM : (REG))
 
 /* The DWARF 2 CFA column which tracks the return address.  */
 #define DWARF_FRAME_RETURN_COLUMN (GP_REG_FIRST + 31)
 
-/* The DWARF 2 CFA column which tracks the return address from a
-   signal handler context.  */
-#define SIGNAL_UNWIND_RETURN_COLUMN (FP_REG_LAST + 1)
-
 /* Before the prologue, RA lives in r31.  */
 #define INCOMING_RETURN_ADDR_RTX  gen_rtx_REG (VOIDmode, GP_REG_FIRST + 31)
 
@@ -1359,6 +1357,12 @@ extern const struct mips_rtx_cost_data *mips_cost;
 #define MD_REG_NUM   (MD_REG_LAST - MD_REG_FIRST + 1)
 #define MD_DBX_FIRST (FP_DBX_FIRST + FP_REG_NUM)
 
+/* The DWARF 2 CFA column which tracks the return address from a
+   signal handler context.  This means that to maintain backwards
+   compatibility, no hard register can be assigned this column if it
+   would need to be handled by the DWARF unwinder.  */
+#define DWARF_ALT_FRAME_RETURN_COLUMN 66
+
 #define ST_REG_FIRST 67
 #define ST_REG_LAST  74
 #define ST_REG_NUM   (ST_REG_LAST - ST_REG_FIRST + 1)