[RFC 02/32] introduce and use find_target_at

[Tom Tromey <tromey@redhat.com>]

RECORD_IS_USED and find_record_target look at
current_target.to_stratum to determine whether a record target is in
use.  This is bad because arch_stratum is greater than record_stratum.

To fix this, this patch adds find_target_at to determine whether a
target appears at a given stratum.  This may seem like overkill
somehow, but I have a subsequent patch series that uses it more
heavily.

2014-01-08  Tom Tromey  <tromey@redhat.com>

	* record.c (find_record_target): Use find_target_at.
	* record.h (RECORD_IS_REPLAY): Use find_target_at.
	* target.c (find_target_at): New function.
	* target.h (find_target_at): Declare.
---
 gdb/ChangeLog |  7 +++++++
 gdb/record.c  |  8 +-------
 gdb/record.h  |  2 +-
 gdb/target.c  | 14 ++++++++++++++
 gdb/target.h  |  5 +++++
 5 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/gdb/record.c b/gdb/record.c
index ec2a042..0fd8756 100644
--- a/gdb/record.c
+++ b/gdb/record.c
@@ -62,13 +62,7 @@ struct cmd_list_element *info_record_cmdlist = NULL;
 static struct target_ops *
 find_record_target (void)
 {
-  struct target_ops *t;
-
-  for (t = current_target.beneath; t != NULL; t = t->beneath)
-    if (t->to_stratum == record_stratum)
-      return t;
-
-  return NULL;
+  return find_target_at (record_stratum);
 }
 
 /* Check that recording is active.  Throw an error, if it isn't.  */
diff --git a/gdb/record.h b/gdb/record.h
index 124c32b..05a17a9 100644
--- a/gdb/record.h
+++ b/gdb/record.h
@@ -22,7 +22,7 @@
 
 struct cmd_list_element;
 
-#define RECORD_IS_USED	(current_target.to_stratum == record_stratum)
+#define RECORD_IS_USED	(find_target_at (record_stratum) != NULL)
 
 extern unsigned int record_debug;
 
diff --git a/gdb/target.c b/gdb/target.c
index 092d50c..d2a40ee 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -3648,6 +3648,20 @@ find_target_beneath (struct target_ops *t)
   return t->beneath;
 }
 
+/* See target.h.  */
+
+struct target_ops *
+find_target_at (enum strata stratum)
+{
+  struct target_ops *t;
+
+  for (t = current_target.beneath; t != NULL; t = t->beneath)
+    if (t->to_stratum == stratum)
+      return t;
+
+  return NULL;
+}
+
 \f
 /* The inferior process has died.  Long live the inferior!  */
 
diff --git a/gdb/target.h b/gdb/target.h
index e00e38c..b219cff 100644
--- a/gdb/target.h
+++ b/gdb/target.h
@@ -1903,6 +1903,11 @@ extern void find_default_create_inferior (struct target_ops *,
 
 extern struct target_ops *find_target_beneath (struct target_ops *);
 
+/* Find the target at STRATUM.  If no target is at that stratum,
+   return NULL.  */
+
+struct target_ops *find_target_at (enum strata stratum);
+
 /* Read OS data object of type TYPE from the target, and return it in
    XML format.  The result is NUL-terminated and returned as a string,
    allocated using xmalloc.  If an error occurs or the transfer is
-- 
1.8.1.4