RFC: don't call add_target for thread_db_ops

Tom Tromey
2013-07-02T16:37:40Z

Right now, "help target" will include this line:

target multi-thread -- Threads and pthreads support

However, it doesn't make sense to invoke "target multi-thread".

This patch fixes the problem by not registering the multi-thread
target. add_target does some needed initialization of the target_ops,
so I broke this out into a new function.

It isn't clear to me whether this patch requires a test case or not.
I'm not sure whether there are other unregistered targets; but if
there are, it seems unlikely that we test for their absence from the
help.

Built and regtested on x86-64 Fedora 18.

* linux-thread-db.c (init_thread_db_ops): Call
complete_target_initialization.
(_initialize_thread_db): Don't call add_target.
* target.c (complete_target_initialization): New function.
(add_target_with_completer): Call it.
* target.h (complete_target_initialization): Declare.
---
gdb/linux-thread-db.c | 3 ++-
gdb/target.c | 23 ++++++++++++++++-------
gdb/target.h | 5 +++++
3 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/gdb/linux-thread-db.c b/gdb/linux-thread-db.c
index 23c29c9..3696827 100644
--- a/gdb/linux-thread-db.c
+++ b/gdb/linux-thread-db.c
@@ -2057,6 +2057,8 @@ init_thread_db_ops (void)
thread_db_ops.to_extra_thread_info = thread_db_extra_thread_info;
thread_db_ops.to_get_ada_task_ptid = thread_db_get_ada_task_ptid;
thread_db_ops.to_magic = OPS_MAGIC;
+
+ complete_target_initialization (&thread_db_ops);
}

/* Provide a prototype to silence -Wmissing-prototypes. */
@@ -2066,7 +2068,6 @@ void
_initialize_thread_db (void)
{
init_thread_db_ops ();
- add_target (&thread_db_ops);

/* Defer loading of libthread_db.so until inferior is running.
This allows gdb to load correct libthread_db for a given
diff --git a/gdb/target.c b/gdb/target.c
index 920f916..5bf8059 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -381,16 +381,12 @@ target_has_execution_current (void)
return target_has_execution_1 (inferior_ptid);
}

-/* Add possible target architecture T to the list and add a new
- command 'target T->to_shortname'. Set COMPLETER as the command's
- completer if not NULL. */
+/* Complete initialization of T. This ensures that various fields in
+ T are set, if needed by the target implementation. */

void
-add_target_with_completer (struct target_ops *t,
- completer_ftype *completer)
+complete_target_initialization (struct target_ops *t)
{
- struct cmd_list_element *c;
-
/* Provide default values for all "must have" methods. */
if (t->to_xfer_partial == NULL)
t->to_xfer_partial = default_xfer_partial;
@@ -409,6 +405,19 @@ add_target_with_completer (struct target_ops *t,

if (t->to_has_execution == NULL)
t->to_has_execution = (int (*) (struct target_ops *, ptid_t)) return_zero;
+}
+
+/* Add possible target architecture T to the list and add a new
+ command 'target T->to_shortname'. Set COMPLETER as the command's
+ completer if not NULL. */
+
+void
+add_target_with_completer (struct target_ops *t,
+ completer_ftype *completer)
+{
+ struct cmd_list_element *c;
+
+ complete_target_initialization (t);

if (!target_structs)
{
diff --git a/gdb/target.h b/gdb/target.h
index 1bf716e..00dad64 100644
--- a/gdb/target.h
+++ b/gdb/target.h
@@ -1837,6 +1837,9 @@ int target_verify_memory (const gdb_byte *data,

/* Routines for maintenance of the target structures...

+ complete_target_initialization: Finalize a target_ops by filling in
+ any fields needed by the target implementation.
+
add_target: Add a target to the list of all possible targets.

push_target: Make this target the top of the stack of currently used
@@ -1855,6 +1858,8 @@ extern void add_target (struct target_ops *);
extern void add_target_with_completer (struct target_ops *t,
completer_ftype *completer);

+extern void complete_target_initialization (struct target_ops *t);
+
/* Adds a command ALIAS for target T and marks it deprecated. This is useful
for maintaining backwards compatibility when renaming targets. */

--
1.8.1.4