If the ObjC Step Through Trampoline plan causes a target crash, properly propagate the error back to

the controlling plans so that they don't lose control.

Also change "ThreadPlanStepThrough" to take the return StackID for its backstop breakpoint as an argument
to the constructor rather than having it try to figure it out itself, since it might get it wrong whereas
the caller always knows where it is coming from.

rdar://problem/11402287

llvm-svn: 156529

1 files changed, 41 insertions, 27 deletions

diff --git a/lldb/source/Target/ThreadPlanStepThrough.cpp b/lldb/source/Target/ThreadPlanStepThrough.cpp
index 3c4824153cb..003d199e379 100644
--- a/lldb/source/Target/ThreadPlanStepThrough.cpp
+++ b/lldb/source/Target/ThreadPlanStepThrough.cpp
@@ -32,11 +32,12 @@ using namespace lldb_private;
 // FIXME: At present only handles DYLD trampolines.
 //----------------------------------------------------------------------
 
-ThreadPlanStepThrough::ThreadPlanStepThrough (Thread &thread, bool stop_others) :
+ThreadPlanStepThrough::ThreadPlanStepThrough (Thread &thread, StackID &m_stack_id, bool stop_others) :
     ThreadPlan (ThreadPlan::eKindStepThrough, "Step through trampolines and prologues", thread, eVoteNoOpinion, eVoteNoOpinion),
     m_start_address (0),
     m_backstop_bkpt_id (LLDB_INVALID_BREAK_ID),
     m_backstop_addr(LLDB_INVALID_ADDRESS),
+    m_return_stack_id (m_stack_id),
     m_stop_others (stop_others)
 {
 
@@ -46,12 +47,11 @@ ThreadPlanStepThrough::ThreadPlanStepThrough (Thread &thread, bool stop_others)
     if (m_sub_plan_sp)
     {
         m_start_address = GetThread().GetRegisterContext()->GetPC(0);
-        m_stack_id = m_thread.GetStackFrameAtIndex(0)->GetStackID();
                 
         // We are going to return back to the concrete frame 1, we might pass by some inlined code that we're in 
         // the middle of by doing this, but it's easier than trying to figure out where the inlined code might return to.
             
-        StackFrameSP return_frame_sp (m_thread.GetFrameWithConcreteFrameIndex(1));
+        StackFrameSP return_frame_sp = m_thread.GetFrameWithStackID (m_stack_id);
         
         if (return_frame_sp)
         {
@@ -73,11 +73,7 @@ ThreadPlanStepThrough::ThreadPlanStepThrough (Thread &thread, bool stop_others)
 
 ThreadPlanStepThrough::~ThreadPlanStepThrough ()
 {
-    if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID)
-    {
-        m_thread.GetProcess()->GetTarget().RemoveBreakpointByID (m_backstop_bkpt_id);
-        m_backstop_bkpt_id = LLDB_INVALID_BREAK_ID;
-    }
+    ClearBackstopBreakpoint ();
 }
 
 void
@@ -161,6 +157,13 @@ ThreadPlanStepThrough::ShouldStop (Event *event_ptr)
     if (IsPlanComplete())
         return true;
         
+    // First, did we hit the backstop breakpoint?
+    if (HitOurBackstopBreakpoint())
+    {
+        SetPlanComplete(false);
+        return true;
+    }
+
     // If we don't have a sub-plan, then we're also done (can't see how we would ever get here
     // without a plan, but just in case.
     
@@ -170,20 +173,27 @@ ThreadPlanStepThrough::ShouldStop (Event *event_ptr)
         return true;
     }
     
-    // First, did we hit the backstop breakpoint?
-    if (HitOurBackstopBreakpoint())
-    {
-        SetPlanComplete();
-        return true;
-    }
-
-
     // If the current sub plan is not done, we don't want to stop.  Actually, we probably won't
     // ever get here in this state, since we generally won't get asked any questions if out
     // current sub-plan is not done...
     if (!m_sub_plan_sp->IsPlanComplete())
+        return false;
+    
+    // If our current sub plan failed, then let's just run to our backstop.  If we can't do that then just stop.
+    if (!m_sub_plan_sp->PlanSucceeded())
+    {
+        if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID)
+        {
+            m_sub_plan_sp.reset();
             return false;
-            
+        }
+        else
+        {
+            SetPlanComplete(false);
+            return true;
+        }
+    }
+        
     // Next see if there is a specific step through plan at our current pc (these might 
     // chain, for instance stepping through a dylib trampoline to the objc dispatch function...)
     LookForPlanToStepThroughFromCurrentPC();
@@ -208,7 +218,7 @@ ThreadPlanStepThrough::StopOthers ()
 StateType
 ThreadPlanStepThrough::GetPlanRunState ()
 {
-    return eStateStepping;
+    return eStateRunning;
 }
 
 bool
@@ -224,14 +234,21 @@ ThreadPlanStepThrough::WillStop ()
     return true;
 }
 
+void
+ThreadPlanStepThrough::ClearBackstopBreakpoint ()
+{
+    if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID)
+    {
+        m_thread.GetProcess()->GetTarget().RemoveBreakpointByID (m_backstop_bkpt_id);
+        m_backstop_bkpt_id = LLDB_INVALID_BREAK_ID;
+    }
+}
+
 bool
 ThreadPlanStepThrough::MischiefManaged ()
 {
     LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
 
-    // ShouldStop will call HappyToStopHere, which will set the plan to complete if
-    // we're done.  So we can just check that here.
-
     if (!IsPlanComplete())
     {
         return false;
@@ -240,12 +257,9 @@ ThreadPlanStepThrough::MischiefManaged ()
     {
         if (log)
             log->Printf("Completed step through step plan.");
+            
+        ClearBackstopBreakpoint ();
         ThreadPlan::MischiefManaged ();
-        if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID)
-        {
-            m_thread.GetProcess()->GetTarget().RemoveBreakpointByID (m_backstop_bkpt_id);
-            m_backstop_bkpt_id = LLDB_INVALID_BREAK_ID;
-        }
         return true;
     }
 }
@@ -262,7 +276,7 @@ ThreadPlanStepThrough::HitOurBackstopBreakpoint()
         {
             StackID cur_frame_zero_id = m_thread.GetStackFrameAtIndex(0)->GetStackID();
             
-            if (cur_frame_zero_id == m_stack_id)
+            if (cur_frame_zero_id == m_return_stack_id)
             {
                 LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
                 if (log)