[PATCH] ada-lang.c:coerce_unspec_val_to_type: Preserve laziness.

[Pedro Alves <palves@redhat.com>]

ada-lang.c:coerce_unspec_val_to_type does:

      if (value_lazy (val)
	  || TYPE_LENGTH (type) > TYPE_LENGTH (value_type (val)))
	result = allocate_value_lazy (type);
      else
	{
	  result = allocate_value (type);
	  memcpy (value_contents_raw (result), value_contents (val),
		  TYPE_LENGTH (type));
	}
      set_value_component_location (result, val);
      set_value_bitsize (result, value_bitsize (val));
      set_value_bitpos (result, value_bitpos (val));
      set_value_address (result, value_address (val));
      set_value_optimized_out (result, value_optimized_out (val));

Notice that before value_optimized_out was made to auto-fetch lazy
values, VAL would end up still lazy if it was lazy on entry.  It's not
really a problem here if VAL is lazy, and VAL->optimized_out is 0,
because RESULT is also left lazy.  IOW, this just wants to copy the
VAL->optimized_out flag to RESULT->optimized_out, nothing else.

The patch adds the value_optimized_out_const function for that.

(I found this out by grepping for set_value_optimized_out and trying
to convert the uses I found to instead allocate the value with
allocate_optimized_out_value.)

Tested on x86_64 Fedora 17.

WDYT?

gdb/
2013-07-04  Pedro Alves  <palves@redhat.com>

	* ada-lang.c (coerce_unspec_val_to_type): Use
	value_optimized_out_const.
	* value.c (value_optimized_out_const): New function.
	* value.h (value_optimized_out_const): New declaration.
---
 gdb/ada-lang.c |    2 +-
 gdb/value.c    |    6 ++++++
 gdb/value.h    |    8 +++++++-
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index 8240fee..dc5f2b6 100644
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -581,7 +581,7 @@ coerce_unspec_val_to_type (struct value *val, struct type *type)
       set_value_bitsize (result, value_bitsize (val));
       set_value_bitpos (result, value_bitpos (val));
       set_value_address (result, value_address (val));
-      set_value_optimized_out (result, value_optimized_out (val));
+      set_value_optimized_out (result, value_optimized_out_const (val));
       return result;
     }
 }
diff --git a/gdb/value.c b/gdb/value.c
index 353f62a..9e58199 100644
--- a/gdb/value.c
+++ b/gdb/value.c
@@ -1062,6 +1062,12 @@ value_optimized_out (struct value *value)
   return value->optimized_out;
 }
 
+int
+value_optimized_out_const (const struct value *value)
+{
+  return value->optimized_out;
+}
+
 void
 set_value_optimized_out (struct value *value, int val)
 {
diff --git a/gdb/value.h b/gdb/value.h
index 8a66aa4..8d669ec 100644
--- a/gdb/value.h
+++ b/gdb/value.h
@@ -319,10 +319,16 @@ extern int value_fetch_lazy (struct value *val);
 extern int value_contents_equal (struct value *val1, struct value *val2);
 
 /* If nonzero, this is the value of a variable which does not actually
-   exist in the program.  */
+   exist in the program, at least partially.  If the value is lazy,
+   this may fetch it now.  */
 extern int value_optimized_out (struct value *value);
 extern void set_value_optimized_out (struct value *value, int val);
 
+/* Like value_optimized_out, but don't fetch the value even if it is
+   lazy.  Mainly useful for constructing other values using VALUE as
+   template.  */
+extern int value_optimized_out_const (const struct value *value);
+
 /* Like value_optimized_out, but return false if any bit in the object
    is valid.  */
 extern int value_entirely_optimized_out (const struct value *value);