Remove save_inferior_ptid

This removes save_inferior_ptid, a cleanup function, in favor of
scoped_restore.

This also fixes a possible (it seems unlikely that it could happen in
practice) memory leak -- save_inferior_ptid should have used
make_cleanup_dtor, because it allocated memory.

I tested this on the buildbot.  However, there are two caveats to
this.  First, sometimes it seems I misread the results.  Second, I
think this patch touches some platforms that can't be tested by the
buildbot.  So, extra care seems warranted.

ChangeLog
2017-08-18  Tom Tromey  <tom@tromey.com>
	    Pedro Alves  <palves@redhat.com>

	* spu-multiarch.c (parse_spufs_run): Use scoped_restore.
	* sol-thread.c (sol_thread_resume, sol_thread_wait)
	(sol_thread_xfer_partial, rw_common): Use scoped_restore.
	* procfs.c (procfs_do_thread_registers): Use scoped_restore.
	* proc-service.c (ps_xfer_memory): Use scoped_restore.
	* linux-tdep.c (linux_corefile_thread): Remove a cleanup.
	(linux_get_siginfo_data): Add "thread" argument.  Use
	scoped_restore.
	* linux-nat.c (linux_child_follow_fork)
	(check_stopped_by_watchpoint): Use scoped_restore.
	* infrun.c (displaced_step_prepare_throw, write_memory_ptid)
	(THREAD_STOPPED_BY, handle_signal_stop): Use scoped_restore.
	(restore_inferior_ptid, save_inferior_ptid): Remove.
	* btrace.c (btrace_fetch): Use scoped_restore.
	* bsd-uthread.c (bsd_uthread_fetch_registers)
	(bsd_uthread_store_registers): Use scoped_restore.
	* breakpoint.c (reattach_breakpoints, detach_breakpoints): Use
	scoped_restore.
	* aix-thread.c (aix_thread_resume, aix_thread_wait)
	(aix_thread_xfer_partial): Use scoped_restore.
	* inferior.h (save_inferior_ptid): Remove.

1 files changed, 7 insertions, 46 deletions

diff --git a/gdb/infrun.c b/gdb/infrun.c
index d6723fd..541fc09 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -1756,7 +1756,7 @@ displaced_step_dump_bytes (struct ui_file *file,
 static int
 displaced_step_prepare_throw (ptid_t ptid)
 {
-  struct cleanup *old_cleanups, *ignore_cleanups;
+  struct cleanup *ignore_cleanups;
   struct thread_info *tp = find_thread_ptid (ptid);
   struct regcache *regcache = get_thread_regcache (ptid);
   struct gdbarch *gdbarch = get_regcache_arch (regcache);
@@ -1808,7 +1808,7 @@ displaced_step_prepare_throw (ptid_t ptid)
 
   displaced_step_clear (displaced);
 
-  old_cleanups = save_inferior_ptid ();
+  scoped_restore save_inferior_ptid = make_scoped_restore (&inferior_ptid);
   inferior_ptid = ptid;
 
   original = regcache_read_pc (regcache);
@@ -1834,7 +1834,6 @@ displaced_step_prepare_throw (ptid_t ptid)
 			      "Stepping over breakpoint in-line instead.\n");
 	}
 
-      do_cleanups (old_cleanups);
       return -1;
     }
 
@@ -1864,7 +1863,7 @@ displaced_step_prepare_throw (ptid_t ptid)
       /* The architecture doesn't know how or want to displaced step
 	 this instruction or instruction sequence.  Fallback to
 	 stepping over the breakpoint in-line.  */
-      do_cleanups (old_cleanups);
+      do_cleanups (ignore_cleanups);
       return -1;
     }
 
@@ -1883,8 +1882,6 @@ displaced_step_prepare_throw (ptid_t ptid)
 
   discard_cleanups (ignore_cleanups);
 
-  do_cleanups (old_cleanups);
-
   if (debug_displaced)
     fprintf_unfiltered (gdb_stdlog, "displaced: displaced pc to %s\n",
 			paddress (gdbarch, copy));
@@ -1941,11 +1938,10 @@ static void
 write_memory_ptid (ptid_t ptid, CORE_ADDR memaddr,
 		   const gdb_byte *myaddr, int len)
 {
-  struct cleanup *ptid_cleanup = save_inferior_ptid ();
+  scoped_restore save_inferior_ptid = make_scoped_restore (&inferior_ptid);
 
   inferior_ptid = ptid;
   write_memory (memaddr, myaddr, len);
-  do_cleanups (ptid_cleanup);
 }
 
 /* Restore the contents of the copy area for thread PTID.  */
@@ -4366,17 +4362,10 @@ wait_one (struct target_waitstatus *ws)
 static int					\
 thread_stopped_by_ ## REASON (ptid_t ptid)	\
 {						\
-  struct cleanup *old_chain;			\
-  int res;					\
-						\
-  old_chain = save_inferior_ptid ();		\
+  scoped_restore save_inferior_ptid = make_scoped_restore (&inferior_ptid); \
   inferior_ptid = ptid;				\
 						\
-  res = target_stopped_by_ ## REASON ();	\
-						\
-  do_cleanups (old_chain);			\
-						\
-  return res;					\
+  return target_stopped_by_ ## REASON ();	\
 }
 
 /* Generate thread_stopped_by_watchpoint.  */
@@ -5706,7 +5695,7 @@ handle_signal_stop (struct execution_control_state *ecs)
     {
       struct regcache *regcache = get_thread_regcache (ecs->ptid);
       struct gdbarch *gdbarch = get_regcache_arch (regcache);
-      struct cleanup *old_chain = save_inferior_ptid ();
+      scoped_restore save_inferior_ptid = make_scoped_restore (&inferior_ptid);
 
       inferior_ptid = ecs->ptid;
 
@@ -5726,8 +5715,6 @@ handle_signal_stop (struct execution_control_state *ecs)
             fprintf_unfiltered (gdb_stdlog,
                                 "infrun: (no data address available)\n");
 	}
-
-      do_cleanups (old_chain);
     }
 
   /* This is originated from start_remote(), start_inferior() and
@@ -9116,32 +9103,6 @@ discard_infcall_control_state (struct infcall_control_state *inf_status)
   xfree (inf_status);
 }
 
-/* restore_inferior_ptid() will be used by the cleanup machinery
-   to restore the inferior_ptid value saved in a call to
-   save_inferior_ptid().  */
-
-static void
-restore_inferior_ptid (void *arg)
-{
-  ptid_t *saved_ptid_ptr = (ptid_t *) arg;
-
-  inferior_ptid = *saved_ptid_ptr;
-  xfree (arg);
-}
-
-/* Save the value of inferior_ptid so that it may be restored by a
-   later call to do_cleanups().  Returns the struct cleanup pointer
-   needed for later doing the cleanup.  */
-
-struct cleanup *
-save_inferior_ptid (void)
-{
-  ptid_t *saved_ptid_ptr = XNEW (ptid_t);
-
-  *saved_ptid_ptr = inferior_ptid;
-  return make_cleanup (restore_inferior_ptid, saved_ptid_ptr);
-}
-
 /* See infrun.h.  */
 
 void