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, 6 deletions

diff --git a/gdb/linux-tdep.c b/gdb/linux-tdep.c
index 5c7f8a0..f5389a0 100644
--- a/gdb/linux-tdep.c
+++ b/gdb/linux-tdep.c
@@ -1649,14 +1649,15 @@ linux_collect_thread_registers (const struct regcache *regcache,
   return data.note_data;
 }
 
-/* Fetch the siginfo data for the current thread, if it exists.  If
+/* Fetch the siginfo data for the specified thread, if it exists.  If
    there is no data, or we could not read it, return NULL.  Otherwise,
    return a newly malloc'd buffer holding the data and fill in *SIZE
    with the size of the data.  The caller is responsible for freeing
    the data.  */
 
 static gdb_byte *
-linux_get_siginfo_data (struct gdbarch *gdbarch, LONGEST *size)
+linux_get_siginfo_data (thread_info *thread, struct gdbarch *gdbarch,
+			LONGEST *size)
 {
   struct type *siginfo_type;
   gdb_byte *buf;
@@ -1666,6 +1667,9 @@ linux_get_siginfo_data (struct gdbarch *gdbarch, LONGEST *size)
   if (!gdbarch_get_siginfo_type_p (gdbarch))
     return NULL;
   
+  scoped_restore save_inferior_ptid = make_scoped_restore (&inferior_ptid);
+  inferior_ptid = thread->ptid;
+
   siginfo_type = gdbarch_get_siginfo_type (gdbarch);
 
   buf = (gdb_byte *) xmalloc (TYPE_LENGTH (siginfo_type));
@@ -1710,11 +1714,8 @@ linux_corefile_thread (struct thread_info *info,
 
   regcache = get_thread_arch_regcache (info->ptid, args->gdbarch);
 
-  old_chain = save_inferior_ptid ();
-  inferior_ptid = info->ptid;
   target_fetch_registers (regcache, -1);
-  siginfo_data = linux_get_siginfo_data (args->gdbarch, &siginfo_size);
-  do_cleanups (old_chain);
+  siginfo_data = linux_get_siginfo_data (info, args->gdbarch, &siginfo_size);
 
   old_chain = make_cleanup (xfree, siginfo_data);