<rdar://problem/13194155>

Variables view out of sync with lldb in Xcode is now fixed. Depending on what happened stack frames could get out of date and a stale shared pointer (one that is no longer a current frame in a thread) could end up being used. 

Now we don't store a weak_ptr to a frame in the ExecutionContextRef class, we just store its stack ID and we always regrab the frame from the thread by stack ID.

llvm-svn: 177208

2 files changed, 6 insertions, 27 deletions

diff --git a/lldb/include/lldb/Target/ExecutionContext.h b/lldb/include/lldb/Target/ExecutionContext.h
index 354c8b62905..de5fe14934a 100644
--- a/lldb/include/lldb/Target/ExecutionContext.h
+++ b/lldb/include/lldb/Target/ExecutionContext.h
@@ -335,7 +335,6 @@ public:
     ClearFrame ()
     {
         m_stack_id.Clear();
-        m_frame_wp.reset();
     }
 
 protected:
@@ -345,7 +344,6 @@ protected:
     lldb::TargetWP m_target_wp;             ///< A weak reference to a target
     lldb::ProcessWP m_process_wp;           ///< A weak reference to a process
     mutable lldb::ThreadWP m_thread_wp;     ///< A weak reference to a thread
-    mutable lldb::StackFrameWP m_frame_wp;  ///< A weak reference to a frame
     lldb::tid_t m_tid;                      ///< The thread ID that this object refers to in case the backing object changes
     StackID m_stack_id;                     ///< The stack ID that this object refers to in case the backing object changes
 };
diff --git a/lldb/source/Target/ExecutionContext.cpp b/lldb/source/Target/ExecutionContext.cpp
index 9ace4c93b17..6ab03553cbc 100644
--- a/lldb/source/Target/ExecutionContext.cpp
+++ b/lldb/source/Target/ExecutionContext.cpp
@@ -524,8 +524,7 @@ ExecutionContextRef::ExecutionContextRef() :
     m_target_wp (),
     m_process_wp (),
     m_thread_wp (),
-    m_frame_wp (),
-    m_tid(LLDB_INVALID_THREAD_ID),  
+    m_tid(LLDB_INVALID_THREAD_ID),
     m_stack_id ()
 {
 }
@@ -534,8 +533,7 @@ ExecutionContextRef::ExecutionContextRef (const ExecutionContext *exe_ctx) :
     m_target_wp (),
     m_process_wp (),
     m_thread_wp (),
-    m_frame_wp (),
-    m_tid(LLDB_INVALID_THREAD_ID),  
+    m_tid(LLDB_INVALID_THREAD_ID),
     m_stack_id ()
 {
     if (exe_ctx)
@@ -546,8 +544,7 @@ ExecutionContextRef::ExecutionContextRef (const ExecutionContext &exe_ctx) :
     m_target_wp (),
     m_process_wp (),
     m_thread_wp (),
-    m_frame_wp (),
-    m_tid(LLDB_INVALID_THREAD_ID),  
+    m_tid(LLDB_INVALID_THREAD_ID),
     m_stack_id ()
 {
     *this = exe_ctx;
@@ -558,8 +555,7 @@ ExecutionContextRef::ExecutionContextRef (Target *target, bool adopt_selected) :
     m_target_wp(),
     m_process_wp(),
     m_thread_wp(),
-    m_frame_wp(),
-    m_tid(LLDB_INVALID_THREAD_ID),  
+    m_tid(LLDB_INVALID_THREAD_ID),
     m_stack_id ()
 {
     SetTargetPtr (target, adopt_selected);
@@ -572,7 +568,6 @@ ExecutionContextRef::ExecutionContextRef (const ExecutionContextRef &rhs) :
     m_target_wp (rhs.m_target_wp),
     m_process_wp(rhs.m_process_wp),
     m_thread_wp (rhs.m_thread_wp),
-    m_frame_wp  (rhs.m_frame_wp),
     m_tid       (rhs.m_tid),
     m_stack_id  (rhs.m_stack_id)
 {
@@ -586,7 +581,6 @@ ExecutionContextRef::operator =(const ExecutionContextRef &rhs)
         m_target_wp  = rhs.m_target_wp;
         m_process_wp = rhs.m_process_wp;
         m_thread_wp  = rhs.m_thread_wp;
-        m_frame_wp   = rhs.m_frame_wp;
         m_tid        = rhs.m_tid;
         m_stack_id   = rhs.m_stack_id;
     }
@@ -605,7 +599,6 @@ ExecutionContextRef::operator =(const ExecutionContext &exe_ctx)
     else
         m_tid = LLDB_INVALID_THREAD_ID;
     lldb::StackFrameSP frame_sp (exe_ctx.GetFrameSP());
-    m_frame_wp = frame_sp;
     if (frame_sp)
         m_stack_id = frame_sp->GetStackID();
     else
@@ -669,7 +662,6 @@ ExecutionContextRef::SetFrameSP (const lldb::StackFrameSP &frame_sp)
 {
     if (frame_sp)
     {
-        m_frame_wp = frame_sp;
         m_stack_id = frame_sp->GetStackID();
         SetThreadSP (frame_sp->GetThread());
     }
@@ -814,20 +806,9 @@ ExecutionContextRef::GetThreadSP () const
 lldb::StackFrameSP
 ExecutionContextRef::GetFrameSP () const
 {
-    lldb::StackFrameSP frame_sp (m_frame_wp.lock());
-    if (frame_sp)
-    {
-        lldb::ThreadSP frame_thread_sp(frame_sp->GetThread());
-        if (frame_thread_sp && frame_thread_sp->IsValid())
-            return frame_sp;
-    }
     lldb::ThreadSP thread_sp (GetThreadSP());
-    if (thread_sp && thread_sp->IsValid())
-    {
-        frame_sp = thread_sp->GetFrameWithStackID (m_stack_id);
-        m_frame_wp = frame_sp;
-        return frame_sp;
-    }
+    if (thread_sp)
+        return thread_sp->GetFrameWithStackID (m_stack_id);
     return lldb::StackFrameSP();
 }