Lock mutex in the same order.

SBProcess uses 2 mutexex; RunLock and APILock. Apart from 2 places, RunLock
is locked before API lock. I have fixed the 2 places where order was different.
I observed a deadlock due to this different order in lldb-mi once. Although
lldb-mi command and event thread dont run at the same time now. So it can not deadlock
there but can still be problem for some other clients.

Pre-approved by Greg in http://lists.cs.uiuc.edu/pipermail/lldb-dev/2015-February/006509.html

llvm-svn: 228844

1 files changed, 2 insertions, 2 deletions

diff --git a/lldb/source/API/SBProcess.cpp b/lldb/source/API/SBProcess.cpp
index 9a0b23bc93d..5de36e302c1 100644
--- a/lldb/source/API/SBProcess.cpp
+++ b/lldb/source/API/SBProcess.cpp
@@ -918,9 +918,9 @@ SBProcess::GetThreadByID (tid_t tid)
     ProcessSP process_sp(GetSP());
     if (process_sp)
     {
-        Mutex::Locker api_locker (process_sp->GetTarget().GetAPIMutex());
         Process::StopLocker stop_locker;
         const bool can_update = stop_locker.TryLock(&process_sp->GetRunLock());
+        Mutex::Locker api_locker (process_sp->GetTarget().GetAPIMutex());
         thread_sp = process_sp->GetThreadList().FindThreadByID (tid, can_update);
         sb_thread.SetThread (thread_sp);
     }
@@ -942,9 +942,9 @@ SBProcess::GetThreadByIndexID (uint32_t index_id)
     ProcessSP process_sp(GetSP());
     if (process_sp)
     {
-        Mutex::Locker api_locker (process_sp->GetTarget().GetAPIMutex());
         Process::StopLocker stop_locker;
         const bool can_update = stop_locker.TryLock(&process_sp->GetRunLock());
+        Mutex::Locker api_locker (process_sp->GetTarget().GetAPIMutex());
         thread_sp = process_sp->GetThreadList().FindThreadByIndexID (index_id, can_update);
         sb_thread.SetThread (thread_sp);
     }