gdb: make thread_info::m_thread_fsm a std::unique_ptr

While working on function calls, I realized that the thread_fsm member
of struct thread_info is a raw pointer to a resource it owns.  This
commit changes the type of the thread_fsm member to a std::unique_ptr in
order to signify this ownership relationship and slightly ease resource
management (no need to manually call delete).

To ensure consistent use, the field is made a private member
(m_thread_fsm).  The setter method (set_thread_fsm) can then check
that it is incorrect to associate a FSM to a thread_info object if
another one is already in place.  This is ensured by an assertion.

The function run_inferior_call takes an argument as a pointer to a
call_thread_fsm and installs it in it in a thread_info instance.  Also
change this function's signature to accept a unique_ptr in order to
signify that the ownership of the call_thread_fsm is transferred during
the call.

No user visible change expected after this commit.

Tested on x86_64-linux with no regression observed.

Change-Id: Ia1224f72a4afa247801ce6650ce82f90224a9ae8

1 files changed, 3 insertions, 3 deletions

diff --git a/gdb/mi/mi-interp.c b/gdb/mi/mi-interp.c
index e69ad9a..f02a7cf 100644
--- a/gdb/mi/mi-interp.c
+++ b/gdb/mi/mi-interp.c
@@ -630,12 +630,12 @@ mi_on_normal_stop_1 (struct bpstat *bs, int print_frame)
 
       tp = inferior_thread ();
 
-      if (tp->thread_fsm != NULL
-	  && tp->thread_fsm->finished_p ())
+      if (tp->thread_fsm () != nullptr
+	  && tp->thread_fsm ()->finished_p ())
 	{
 	  enum async_reply_reason reason;
 
-	  reason = tp->thread_fsm->async_reply_reason ();
+	  reason = tp->thread_fsm ()->async_reply_reason ();
 	  mi_uiout->field_string ("reason", async_reason_lookup (reason));
 	}