Thread hardening part 3. Now lldb_private::Thread objects have std::weak_ptr
objects for the backlink to the lldb_private::Process. The issues we were
running into before was someone was holding onto a shared pointer to a 
lldb_private::Thread for too long, and the lldb_private::Process parent object
would get destroyed and the lldb_private::Thread had a "Process &m_process"
member which would just treat whatever memory that used to be a Process as a
valid Process. This was mostly happening for lldb_private::StackFrame objects
that had a member like "Thread &m_thread". So this completes the internal
strong/weak changes.

Documented the ExecutionContext and ExecutionContextRef classes so that our
LLDB developers can understand when and where to use ExecutionContext and 
ExecutionContextRef objects.



git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@151009 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/source/Target/ThreadPlanStepThrough.cpp b/source/Target/ThreadPlanStepThrough.cpp
index 606cfd1..cb7bf99 100644
--- a/source/Target/ThreadPlanStepThrough.cpp
+++ b/source/Target/ThreadPlanStepThrough.cpp
@@ -56,8 +56,8 @@
         
         if (return_frame_sp)
         {
-            m_backstop_addr = return_frame_sp->GetFrameCodeAddress().GetLoadAddress(&m_thread.GetProcess().GetTarget());
-            Breakpoint *return_bp = m_thread.GetProcess().GetTarget().CreateBreakpoint (m_backstop_addr, true).get();
+            m_backstop_addr = return_frame_sp->GetFrameCodeAddress().GetLoadAddress(m_thread.CalculateTarget().get());
+            Breakpoint *return_bp = m_thread.GetProcess()->GetTarget().CreateBreakpoint (m_backstop_addr, true).get();
             if (return_bp != NULL)
             {
                 return_bp->SetThreadID(m_thread.GetID());
@@ -76,7 +76,7 @@
 {
     if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID)
     {
-        m_thread.GetProcess().GetTarget().RemoveBreakpointByID (m_backstop_bkpt_id);
+        m_thread.GetProcess()->GetTarget().RemoveBreakpointByID (m_backstop_bkpt_id);
         m_backstop_bkpt_id = LLDB_INVALID_BREAK_ID;
     }
 }
@@ -91,11 +91,11 @@
 void
 ThreadPlanStepThrough::LookForPlanToStepThroughFromCurrentPC()
 {
-    m_sub_plan_sp = m_thread.GetProcess().GetDynamicLoader()->GetStepThroughTrampolinePlan (m_thread, m_stop_others);
+    m_sub_plan_sp = m_thread.GetProcess()->GetDynamicLoader()->GetStepThroughTrampolinePlan (m_thread, m_stop_others);
     // If that didn't come up with anything, try the ObjC runtime plugin:
     if (!m_sub_plan_sp.get())
     {
-        ObjCLanguageRuntime *objc_runtime = m_thread.GetProcess().GetObjCLanguageRuntime();
+        ObjCLanguageRuntime *objc_runtime = m_thread.GetProcess()->GetObjCLanguageRuntime();
         if (objc_runtime)
             m_sub_plan_sp = objc_runtime->GetStepThroughTrampolinePlan (m_thread, m_stop_others);
     }
@@ -244,7 +244,7 @@
         ThreadPlan::MischiefManaged ();
         if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID)
         {
-            m_thread.GetProcess().GetTarget().RemoveBreakpointByID (m_backstop_bkpt_id);
+            m_thread.GetProcess()->GetTarget().RemoveBreakpointByID (m_backstop_bkpt_id);
             m_backstop_bkpt_id = LLDB_INVALID_BREAK_ID;
         }
         return true;
@@ -258,7 +258,7 @@
     if (stop_info_sp && stop_info_sp->GetStopReason() == eStopReasonBreakpoint)
     {
         break_id_t stop_value = (break_id_t) stop_info_sp->GetValue();
-        BreakpointSiteSP cur_site_sp = m_thread.GetProcess().GetBreakpointSiteList().FindByID(stop_value);
+        BreakpointSiteSP cur_site_sp = m_thread.GetProcess()->GetBreakpointSiteList().FindByID(stop_value);
         if (cur_site_sp && cur_site_sp->IsBreakpointAtThisSite(m_backstop_bkpt_id))
         {
             size_t current_stack_depth = m_thread.GetStackFrameCount();