[PATCH 04/12] Introduce OPTIMIZED_OUT_ERROR.

["Andrew Burgess" <aburgess@broadcom.com>]

We already have a NOT_AVAILABLE_ERROR, this patch adds
an OPTIMIZED_OUT_ERROR.

It is not clear to me if the original intention of the
NOT_AVAILABLE_ERROR was to cover all reasons why a value
is missing, but from how it is currently used the
NOT_AVAILABLE_ERROR is for specifically the case where
a value is unavailable.   So, in order to catch the
optimized out errors just like we catch the unavailable
errors, I've added a new error code, and throw it in
various places.

OK to apply?

Thanks,
Andrew

gdb/ChangeLog

2013-08-08  Andrew Burgess  <aburgess@broadcom.com>

	* exceptions.h (errors): Add OPTIMIZED_OUT_ERROR.
	* exceptions.c (is_unavailable_error): Check for
	OPTIMIZED_OUT_ERROR.
	* dwarf2loc.c (write_pieced_value): Throw OPTIMIZED_OUT_ERROR.
	* frame.c (frame_unwind_pc_if_available): Display correct string
	for optimized out or unavailable values.
	(frame_unwind_register): Throw OPTIMIZED_OUT_ERROR.
	* spu-tdep.c (spu_software_single_step): Throw
	OPTIMIZED_OUT_ERROR.
	* valops.c (value_assign): Throw OPTIMIZED_OUT_ERROR.

diff --git a/gdb/dwarf2loc.c b/gdb/dwarf2loc.c
index 36b80fb..bae425a 100644
--- a/gdb/dwarf2loc.c
+++ b/gdb/dwarf2loc.c
@@ -1880,9 +1880,10 @@ write_pieced_value (struct value *to, struct
value *from)
 						   &optim, &unavail))
 		      {
 			if (optim)
-			  error (_("Can't do read-modify-write to "
-				   "update bitfield; containing word has been "
-				   "optimized out"));
+			  throw_error (OPTIMIZED_OUT_ERROR,
+				       _("Can't do read-modify-write to "
+					 "update bitfield; containing word "
+					 "has been optimized out"));
 			if (unavail)
 			  throw_error (NOT_AVAILABLE_ERROR,
 				       _("Can't do read-modify-write to update "
diff --git a/gdb/exceptions.c b/gdb/exceptions.c
index 134d918..c6248bc 100644
--- a/gdb/exceptions.c
+++ b/gdb/exceptions.c
@@ -577,5 +577,6 @@ catch_command_errors_const
(catch_command_errors_const_ftype *command,
 int
 is_unavailable_error (const enum errors error)
 {
-  return error == NOT_AVAILABLE_ERROR;
+  return (error == NOT_AVAILABLE_ERROR
+	  || error == OPTIMIZED_OUT_ERROR);
 }
diff --git a/gdb/exceptions.h b/gdb/exceptions.h
index 1baecf4..f2cc528 100644
--- a/gdb/exceptions.h
+++ b/gdb/exceptions.h
@@ -79,9 +79,9 @@ enum errors {
   /* Feature is not supported in this copy of GDB.  */
   UNSUPPORTED_ERROR,
 -  /* Value not available.  E.g., a register was not collected in a
-     traceframe.  */
-  NOT_AVAILABLE_ERROR,
+  /* Value not available.  */
+  NOT_AVAILABLE_ERROR, /* Not collected, e.g. in a traceframe.  */
+  OPTIMIZED_OUT_ERROR, /* Optimized out by compiler or ABI.  */
    /* DW_OP_GNU_entry_value resolving failed.  */
   NO_ENTRY_VALUE_ERROR,
diff --git a/gdb/frame.c b/gdb/frame.c
index 54f828c..f825f96 100644
--- a/gdb/frame.c
+++ b/gdb/frame.c
@@ -728,8 +728,11 @@ frame_unwind_pc_if_available (struct frame_info
*this_frame, CORE_ADDR *pc)
 	      if (frame_debug)
 		fprintf_unfiltered (gdb_stdlog,
 				    "{ frame_unwind_pc (this_frame=%d)"
-				    " -> <unavailable> }\n",
-				    this_frame->level);
+				    " -> %s }\n",
+				    this_frame->level,
+				    (ex.error == NOT_AVAILABLE_ERROR
+				     ? "<unavailable>"
+				     : "<optimized out>"));
 	    }
 	  else if (ex.reason < 0)
 	    {
@@ -988,7 +991,8 @@ frame_unwind_register (struct frame_info *frame, int
regnum, gdb_byte *buf)
 			 &lval, &addr, &realnum, buf);
    if (optimized)
-    error (_("Register %d was optimized out"), regnum);
+    throw_error (OPTIMIZED_OUT_ERROR,
+		 _("Register %d was optimized out"), regnum);
   if (unavailable)
     throw_error (NOT_AVAILABLE_ERROR,
 		 _("Register %d is not available"), regnum);
diff --git a/gdb/spu-tdep.c b/gdb/spu-tdep.c
index 46f3e2c..6fa3e7e 100644
--- a/gdb/spu-tdep.c
+++ b/gdb/spu-tdep.c
@@ -1614,8 +1614,9 @@ spu_software_single_step (struct frame_info *frame)
 	  else
 	    {
 	      if (optim)
-		error (_("Could not determine address of "
-			 "single-step breakpoint."));
+		throw_error (OPTIMIZED_OUT_ERROR,
+			     _("Could not determine address of "
+			       "single-step breakpoint."));
 	      if (unavail)
 		throw_error (NOT_AVAILABLE_ERROR,
 			     _("Could not determine address of "
diff --git a/gdb/valops.c b/gdb/valops.c
index f86b283..48dbeaa 100644
--- a/gdb/valops.c
+++ b/gdb/valops.c
@@ -1188,7 +1188,8 @@ value_assign (struct value *toval, struct value
*fromval)
 					       &optim, &unavail))
 		  {
 		    if (optim)
-		      error (_("value has been optimized out"));
+		      throw_error (OPTIMIZED_OUT_ERROR,
+				   _("value has been optimized out"));
 		    if (unavail)
 		      throw_error (NOT_AVAILABLE_ERROR,
 				   _("value is not available"));