[COMMIT PATCH] value_bits_valid: Fix latent bug.

[Pedro Alves <palves at redhat dot com>]

Doing something else, I factored out the bits of the value_bits_valid
function that actually handle the check_validity hook, and
surprisingly found out that the result was misbehaving.  Turns out
value_bits_valid has a latent bug.  If the value is not lval_computed,
or doesn't have a check_validity hook, then we should assume the value
is entirely valid, not invalid.  This is currently masked by the
value->optimized_out check -- I ran the testsuite with a gdb_assert(0)
inserted in place of that return being touched by the patch, and it
never triggers.

Tested on x86_64 Fedora 17.

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

	* value.c (value_bits_valid): If the value is not lval_computed,
	or doesn't have a check_validity hook, assume the value is entirely
	valid.
---
 gdb/value.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gdb/value.c b/gdb/value.c
index ce4b13a..353f62a 100644
--- a/gdb/value.c
+++ b/gdb/value.c
@@ -1086,7 +1086,7 @@ value_bits_valid (const struct value *value, int offset, int length)
     return 1;
   if (value->lval != lval_computed
       || !value->location.computed.funcs->check_validity)
-    return 0;
+    return 1;
   return value->location.computed.funcs->check_validity (value, offset,
 							 length);
 }