Added a new Host class: ReadWriteLock

This abstracts read/write locks on the current host system. It is currently backed by pthread_rwlock_t objects so it should work on all unix systems.

We also need a way to control multi-threaded access to the process through the public API when it is running. For example it isn't a good idea to try and get stack frames while the process is running. To implement this, the lldb_private::Process class now contains a ReadWriteLock member variable named m_run_lock which is used to control the public process state. The public process state represents the state of the process as the client knows it. The private is used to control the actual current process state. So the public state of the process can be stopped, yet the private state can be running when evaluating an expression for example. 

Adding the read/write lock where readers are clients that want the process to stay stopped, and writers are clients that run the process, allows us to accurately control multi-threaded access to the process.

Switched the SBThread and SBFrame over to us shared pointers to the ExecutionContextRef class instead of making their own class to track this. This fixed an issue with assigning on SBFrame to another and will also centralize the code that tracks weak references to execution context objects into one location.

llvm-svn: 154099

1 files changed, 241 insertions, 194 deletions

diff --git a/lldb/source/API/SBThread.cpp b/lldb/source/API/SBThread.cpp
index ff2a68ca135..510f7420a49 100644
--- a/lldb/source/API/SBThread.cpp
+++ b/lldb/source/API/SBThread.cpp
@@ -43,18 +43,19 @@ using namespace lldb_private;
 // Constructors
 //----------------------------------------------------------------------
 SBThread::SBThread () :
-    m_opaque_wp ()
+    m_opaque_sp (new ExecutionContextRef())
 {
 }
 
 SBThread::SBThread (const ThreadSP& lldb_object_sp) :
-    m_opaque_wp (lldb_object_sp)
+    m_opaque_sp (new ExecutionContextRef(lldb_object_sp))
 {
 }
 
 SBThread::SBThread (const SBThread &rhs) :
-    m_opaque_wp (rhs.m_opaque_wp)
+    m_opaque_sp (new ExecutionContextRef(*rhs.m_opaque_sp))
 {
+    
 }
 
 //----------------------------------------------------------------------
@@ -65,7 +66,7 @@ const lldb::SBThread &
 SBThread::operator = (const SBThread &rhs)
 {
     if (this != &rhs)
-        m_opaque_wp = rhs.m_opaque_wp;
+        *m_opaque_sp = *rhs.m_opaque_sp;
     return *this;
 }
 
@@ -79,13 +80,13 @@ SBThread::~SBThread()
 bool
 SBThread::IsValid() const
 {
-    return !m_opaque_wp.expired();
+    return m_opaque_sp->GetThreadSP().get() != NULL;
 }
 
 void
 SBThread::Clear ()
 {
-    m_opaque_wp.reset();
+    m_opaque_sp->Clear();
 }
 
 
@@ -95,13 +96,17 @@ SBThread::GetStopReason()
     LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_API));
 
     StopReason reason = eStopReasonInvalid;
-    ExecutionContext exe_ctx (m_opaque_wp);
+    ExecutionContext exe_ctx (m_opaque_sp.get());
     if (exe_ctx.HasThreadScope())
     {
-        Mutex::Locker api_locker (exe_ctx.GetTargetPtr()->GetAPIMutex());
-        StopInfoSP stop_info_sp = exe_ctx.GetThreadPtr()->GetStopInfo ();
-        if (stop_info_sp)
-            reason =  stop_info_sp->GetStopReason();
+        Process::StopLocker stop_locker;
+        if (stop_locker.TryLock(&exe_ctx.GetProcessPtr()->GetRunLock()))
+        {
+            Mutex::Locker api_locker (exe_ctx.GetTargetPtr()->GetAPIMutex());
+            StopInfoSP stop_info_sp = exe_ctx.GetThreadPtr()->GetStopInfo ();
+            if (stop_info_sp)
+                reason =  stop_info_sp->GetStopReason();
+        }
     }
 
     if (log)
@@ -114,42 +119,46 @@ SBThread::GetStopReason()
 size_t
 SBThread::GetStopReasonDataCount ()
 {
-    ExecutionContext exe_ctx (m_opaque_wp);
+    ExecutionContext exe_ctx (m_opaque_sp.get());
     if (exe_ctx.HasThreadScope())
     {
-        Mutex::Locker api_locker (exe_ctx.GetTargetPtr()->GetAPIMutex());
-        StopInfoSP stop_info_sp = exe_ctx.GetThreadPtr()->GetStopInfo ();
-        if (stop_info_sp)
+        Process::StopLocker stop_locker;
+        if (stop_locker.TryLock(&exe_ctx.GetProcessPtr()->GetRunLock()))
         {
-            StopReason reason = stop_info_sp->GetStopReason();
-            switch (reason)
+            Mutex::Locker api_locker (exe_ctx.GetTargetPtr()->GetAPIMutex());
+            StopInfoSP stop_info_sp = exe_ctx.GetThreadPtr()->GetStopInfo ();
+            if (stop_info_sp)
             {
-            case eStopReasonInvalid:
-            case eStopReasonNone:
-            case eStopReasonTrace:
-            case eStopReasonPlanComplete:
-                // There is no data for these stop reasons.
-                return 0;
-
-            case eStopReasonBreakpoint:
+                StopReason reason = stop_info_sp->GetStopReason();
+                switch (reason)
                 {
-                    break_id_t site_id = stop_info_sp->GetValue();
-                    lldb::BreakpointSiteSP bp_site_sp (exe_ctx.GetProcessPtr()->GetBreakpointSiteList().FindByID (site_id));
-                    if (bp_site_sp)
-                        return bp_site_sp->GetNumberOfOwners () * 2;
-                    else
-                        return 0; // Breakpoint must have cleared itself...
-                }
-                break;
+                case eStopReasonInvalid:
+                case eStopReasonNone:
+                case eStopReasonTrace:
+                case eStopReasonPlanComplete:
+                    // There is no data for these stop reasons.
+                    return 0;
+
+                case eStopReasonBreakpoint:
+                    {
+                        break_id_t site_id = stop_info_sp->GetValue();
+                        lldb::BreakpointSiteSP bp_site_sp (exe_ctx.GetProcessPtr()->GetBreakpointSiteList().FindByID (site_id));
+                        if (bp_site_sp)
+                            return bp_site_sp->GetNumberOfOwners () * 2;
+                        else
+                            return 0; // Breakpoint must have cleared itself...
+                    }
+                    break;
 
-            case eStopReasonWatchpoint:
-                return 1;
+                case eStopReasonWatchpoint:
+                    return 1;
 
-            case eStopReasonSignal:
-                return 1;
+                case eStopReasonSignal:
+                    return 1;
 
-            case eStopReasonException:
-                return 1;
+                case eStopReasonException:
+                    return 1;
+                }
             }
         }
     }
@@ -159,58 +168,63 @@ SBThread::GetStopReasonDataCount ()
 uint64_t
 SBThread::GetStopReasonDataAtIndex (uint32_t idx)
 {
-    ExecutionContext exe_ctx (m_opaque_wp);
+    ExecutionContext exe_ctx (m_opaque_sp.get());
     if (exe_ctx.HasThreadScope())
     {
-        Mutex::Locker api_locker (exe_ctx.GetTargetPtr()->GetAPIMutex());
-        Thread *thread = exe_ctx.GetThreadPtr();
-        StopInfoSP stop_info_sp = thread->GetStopInfo ();
-        if (stop_info_sp)
+        Process::StopLocker stop_locker;
+        if (stop_locker.TryLock(&exe_ctx.GetProcessPtr()->GetRunLock()))
         {
-            StopReason reason = stop_info_sp->GetStopReason();
-            switch (reason)
+
+            Mutex::Locker api_locker (exe_ctx.GetTargetPtr()->GetAPIMutex());
+            Thread *thread = exe_ctx.GetThreadPtr();
+            StopInfoSP stop_info_sp = thread->GetStopInfo ();
+            if (stop_info_sp)
             {
-            case eStopReasonInvalid:
-            case eStopReasonNone:
-            case eStopReasonTrace:
-            case eStopReasonPlanComplete:
-                // There is no data for these stop reasons.
-                return 0;
-
-            case eStopReasonBreakpoint:
+                StopReason reason = stop_info_sp->GetStopReason();
+                switch (reason)
                 {
-                    break_id_t site_id = stop_info_sp->GetValue();
-                    lldb::BreakpointSiteSP bp_site_sp (exe_ctx.GetProcessPtr()->GetBreakpointSiteList().FindByID (site_id));
-                    if (bp_site_sp)
+                case eStopReasonInvalid:
+                case eStopReasonNone:
+                case eStopReasonTrace:
+                case eStopReasonPlanComplete:
+                    // There is no data for these stop reasons.
+                    return 0;
+
+                case eStopReasonBreakpoint:
                     {
-                        uint32_t bp_index = idx / 2;
-                        BreakpointLocationSP bp_loc_sp (bp_site_sp->GetOwnerAtIndex (bp_index));
-                        if (bp_loc_sp)
+                        break_id_t site_id = stop_info_sp->GetValue();
+                        lldb::BreakpointSiteSP bp_site_sp (exe_ctx.GetProcessPtr()->GetBreakpointSiteList().FindByID (site_id));
+                        if (bp_site_sp)
                         {
-                            if (bp_index & 1)
-                            {
-                                // Odd idx, return the breakpoint location ID
-                                return bp_loc_sp->GetID();
-                            }
-                            else
+                            uint32_t bp_index = idx / 2;
+                            BreakpointLocationSP bp_loc_sp (bp_site_sp->GetOwnerAtIndex (bp_index));
+                            if (bp_loc_sp)
                             {
-                                // Even idx, return the breakpoint ID
-                                return bp_loc_sp->GetBreakpoint().GetID();
+                                if (bp_index & 1)
+                                {
+                                    // Odd idx, return the breakpoint location ID
+                                    return bp_loc_sp->GetID();
+                                }
+                                else
+                                {
+                                    // Even idx, return the breakpoint ID
+                                    return bp_loc_sp->GetBreakpoint().GetID();
+                                }
                             }
                         }
+                        return LLDB_INVALID_BREAK_ID;
                     }
-                    return LLDB_INVALID_BREAK_ID;
-                }
-                break;
+                    break;
 
-            case eStopReasonWatchpoint:
-                return stop_info_sp->GetValue();
+                case eStopReasonWatchpoint:
+                    return stop_info_sp->GetValue();
 
-            case eStopReasonSignal:
-                return stop_info_sp->GetValue();
+                case eStopReasonSignal:
+                    return stop_info_sp->GetValue();
 
-            case eStopReasonException:
-                return stop_info_sp->GetValue();
+                case eStopReasonException:
+                    return stop_info_sp->GetValue();
+                }
             }
         }
     }
@@ -222,94 +236,99 @@ SBThread::GetStopDescription (char *dst, size_t dst_len)
 {
     LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_API));
 
-    ExecutionContext exe_ctx (m_opaque_wp);
+    ExecutionContext exe_ctx (m_opaque_sp.get());
     if (exe_ctx.HasThreadScope())
     {
-        Mutex::Locker api_locker (exe_ctx.GetTargetPtr()->GetAPIMutex());
-        StopInfoSP stop_info_sp = exe_ctx.GetThreadPtr()->GetStopInfo ();
-        if (stop_info_sp)
+        Process::StopLocker stop_locker;
+        if (stop_locker.TryLock(&exe_ctx.GetProcessPtr()->GetRunLock()))
         {
-            const char *stop_desc = stop_info_sp->GetDescription();
-            if (stop_desc)
+
+            Mutex::Locker api_locker (exe_ctx.GetTargetPtr()->GetAPIMutex());
+            StopInfoSP stop_info_sp = exe_ctx.GetThreadPtr()->GetStopInfo ();
+            if (stop_info_sp)
             {
-                if (log)
-                    log->Printf ("SBThread(%p)::GetStopDescription (dst, dst_len) => \"%s\"", 
-                                 exe_ctx.GetThreadPtr(), stop_desc);
-                if (dst)
-                    return ::snprintf (dst, dst_len, "%s", stop_desc);
-                else
+                const char *stop_desc = stop_info_sp->GetDescription();
+                if (stop_desc)
                 {
-                    // NULL dst passed in, return the length needed to contain the description
-                    return ::strlen (stop_desc) + 1; // Include the NULL byte for size
+                    if (log)
+                        log->Printf ("SBThread(%p)::GetStopDescription (dst, dst_len) => \"%s\"", 
+                                     exe_ctx.GetThreadPtr(), stop_desc);
+                    if (dst)
+                        return ::snprintf (dst, dst_len, "%s", stop_desc);
+                    else
+                    {
+                        // NULL dst passed in, return the length needed to contain the description
+                        return ::strlen (stop_desc) + 1; // Include the NULL byte for size
+                    }
                 }
-            }
-            else
-            {
-                size_t stop_desc_len = 0;
-                switch (stop_info_sp->GetStopReason())
+                else
                 {
-                case eStopReasonTrace:
-                case eStopReasonPlanComplete:
+                    size_t stop_desc_len = 0;
+                    switch (stop_info_sp->GetStopReason())
                     {
-                        static char trace_desc[] = "step";
-                        stop_desc = trace_desc;
-                        stop_desc_len = sizeof(trace_desc); // Include the NULL byte for size
-                    }
-                    break;
+                    case eStopReasonTrace:
+                    case eStopReasonPlanComplete:
+                        {
+                            static char trace_desc[] = "step";
+                            stop_desc = trace_desc;
+                            stop_desc_len = sizeof(trace_desc); // Include the NULL byte for size
+                        }
+                        break;
 
-                case eStopReasonBreakpoint:
-                    {
-                        static char bp_desc[] = "breakpoint hit";
-                        stop_desc = bp_desc;
-                        stop_desc_len = sizeof(bp_desc); // Include the NULL byte for size
-                    }
-                    break;
+                    case eStopReasonBreakpoint:
+                        {
+                            static char bp_desc[] = "breakpoint hit";
+                            stop_desc = bp_desc;
+                            stop_desc_len = sizeof(bp_desc); // Include the NULL byte for size
+                        }
+                        break;
 
-                case eStopReasonWatchpoint:
-                    {
-                        static char wp_desc[] = "watchpoint hit";
-                        stop_desc = wp_desc;
-                        stop_desc_len = sizeof(wp_desc); // Include the NULL byte for size
-                    }
-                    break;
+                    case eStopReasonWatchpoint:
+                        {
+                            static char wp_desc[] = "watchpoint hit";
+                            stop_desc = wp_desc;
+                            stop_desc_len = sizeof(wp_desc); // Include the NULL byte for size
+                        }
+                        break;
 
-                case eStopReasonSignal:
-                    {
-                        stop_desc = exe_ctx.GetProcessPtr()->GetUnixSignals ().GetSignalAsCString (stop_info_sp->GetValue());
-                        if (stop_desc == NULL || stop_desc[0] == '\0')
+                    case eStopReasonSignal:
                         {
-                            static char signal_desc[] = "signal";
-                            stop_desc = signal_desc;
-                            stop_desc_len = sizeof(signal_desc); // Include the NULL byte for size
+                            stop_desc = exe_ctx.GetProcessPtr()->GetUnixSignals ().GetSignalAsCString (stop_info_sp->GetValue());
+                            if (stop_desc == NULL || stop_desc[0] == '\0')
+                            {
+                                static char signal_desc[] = "signal";
+                                stop_desc = signal_desc;
+                                stop_desc_len = sizeof(signal_desc); // Include the NULL byte for size
+                            }
                         }
-                    }
-                    break;
+                        break;
 
-                case eStopReasonException:
-                    {
-                        char exc_desc[] = "exception";
-                        stop_desc = exc_desc;
-                        stop_desc_len = sizeof(exc_desc); // Include the NULL byte for size
-                    }
-                    break;          
+                    case eStopReasonException:
+                        {
+                            char exc_desc[] = "exception";
+                            stop_desc = exc_desc;
+                            stop_desc_len = sizeof(exc_desc); // Include the NULL byte for size
+                        }
+                        break;          
 
-                default:
-                    break;
-                }
-                
-                if (stop_desc && stop_desc[0])
-                {
-                    if (log)
-                        log->Printf ("SBThread(%p)::GetStopDescription (dst, dst_len) => '%s'", 
-                                     exe_ctx.GetThreadPtr(), stop_desc);
+                    default:
+                        break;
+                    }
+                    
+                    if (stop_desc && stop_desc[0])
+                    {
+                        if (log)
+                            log->Printf ("SBThread(%p)::GetStopDescription (dst, dst_len) => '%s'", 
+                                         exe_ctx.GetThreadPtr(), stop_desc);
 
-                    if (dst)
-                        return ::snprintf (dst, dst_len, "%s", stop_desc) + 1; // Include the NULL byte
+                        if (dst)
+                            return ::snprintf (dst, dst_len, "%s", stop_desc) + 1; // Include the NULL byte
 
-                    if (stop_desc_len == 0)
-                        stop_desc_len = ::strlen (stop_desc) + 1; // Include the NULL byte
-                        
-                    return stop_desc_len;
+                        if (stop_desc_len == 0)
+                            stop_desc_len = ::strlen (stop_desc) + 1; // Include the NULL byte
+                            
+                        return stop_desc_len;
+                    }
                 }
             }
         }
@@ -323,14 +342,18 @@ SBValue
 SBThread::GetStopReturnValue ()
 {
     ValueObjectSP return_valobj_sp;
-    ExecutionContext exe_ctx (m_opaque_wp);
+    ExecutionContext exe_ctx (m_opaque_sp.get());
     if (exe_ctx.HasThreadScope())
     {
-        Mutex::Locker api_locker (exe_ctx.GetTargetPtr()->GetAPIMutex());
-        StopInfoSP stop_info_sp = exe_ctx.GetThreadPtr()->GetStopInfo ();
-        if (stop_info_sp)
+        Process::StopLocker stop_locker;
+        if (stop_locker.TryLock(&exe_ctx.GetProcessPtr()->GetRunLock()))
         {
-            return_valobj_sp = StopInfo::GetReturnValueObject (stop_info_sp);
+            Mutex::Locker api_locker (exe_ctx.GetTargetPtr()->GetAPIMutex());
+            StopInfoSP stop_info_sp = exe_ctx.GetThreadPtr()->GetStopInfo ();
+            if (stop_info_sp)
+            {
+                return_valobj_sp = StopInfo::GetReturnValueObject (stop_info_sp);
+            }
         }
     }
     
@@ -347,14 +370,14 @@ SBThread::GetStopReturnValue ()
 void
 SBThread::SetThread (const ThreadSP& lldb_object_sp)
 {
-    m_opaque_wp = lldb_object_sp;
+    m_opaque_sp->SetThreadSP (lldb_object_sp);
 }
 
 
 lldb::tid_t
 SBThread::GetThreadID () const
 {
-    ThreadSP thread_sp(m_opaque_wp.lock());
+    ThreadSP thread_sp(m_opaque_sp->GetThreadSP());
     if (thread_sp)
         return thread_sp->GetID();
     return LLDB_INVALID_THREAD_ID;
@@ -363,7 +386,7 @@ SBThread::GetThreadID () const
 uint32_t
 SBThread::GetIndexID () const
 {
-    ThreadSP thread_sp(m_opaque_wp.lock());
+    ThreadSP thread_sp(m_opaque_sp->GetThreadSP());
     if (thread_sp)
         return thread_sp->GetIndexID();
     return LLDB_INVALID_INDEX32;
@@ -373,11 +396,15 @@ const char *
 SBThread::GetName () const
 {
     const char *name = NULL;
-    ExecutionContext exe_ctx (m_opaque_wp);
+    ExecutionContext exe_ctx (m_opaque_sp.get());
     if (exe_ctx.HasThreadScope())
     {
-        Mutex::Locker api_locker (exe_ctx.GetTargetPtr()->GetAPIMutex());
-        name = exe_ctx.GetThreadPtr()->GetName();
+        Process::StopLocker stop_locker;
+        if (stop_locker.TryLock(&exe_ctx.GetProcessPtr()->GetRunLock()))
+        {
+            Mutex::Locker api_locker (exe_ctx.GetTargetPtr()->GetAPIMutex());
+            name = exe_ctx.GetThreadPtr()->GetName();
+        }
     }
     
     LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_API));
@@ -391,11 +418,15 @@ const char *
 SBThread::GetQueueName () const
 {
     const char *name = NULL;
-    ExecutionContext exe_ctx (m_opaque_wp);
+    ExecutionContext exe_ctx (m_opaque_sp.get());
     if (exe_ctx.HasThreadScope())
     {
-        Mutex::Locker api_locker (exe_ctx.GetTargetPtr()->GetAPIMutex());
-        name = exe_ctx.GetThreadPtr()->GetQueueName();
+        Process::StopLocker stop_locker;
+        if (stop_locker.TryLock(&exe_ctx.GetProcessPtr()->GetRunLock()))
+        {
+            Mutex::Locker api_locker (exe_ctx.GetTargetPtr()->GetAPIMutex());
+            name = exe_ctx.GetThreadPtr()->GetQueueName();
+        }
     }
     
     LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_API));
@@ -411,7 +442,7 @@ SBThread::StepOver (lldb::RunMode stop_other_threads)
 {
     LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_API));
 
-    ExecutionContext exe_ctx (m_opaque_wp);
+    ExecutionContext exe_ctx (m_opaque_sp.get());
 
     if (log)
         log->Printf ("SBThread(%p)::StepOver (stop_other_threads='%s')", exe_ctx.GetThreadPtr(), 
@@ -464,7 +495,7 @@ SBThread::StepInto (lldb::RunMode stop_other_threads)
 {
     LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_API));
 
-    ExecutionContext exe_ctx (m_opaque_wp);
+    ExecutionContext exe_ctx (m_opaque_sp.get());
 
     if (log)
         log->Printf ("SBThread(%p)::StepInto (stop_other_threads='%s')", exe_ctx.GetThreadPtr(),
@@ -514,7 +545,7 @@ SBThread::StepOut ()
 {
     LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_API));
 
-    ExecutionContext exe_ctx (m_opaque_wp);
+    ExecutionContext exe_ctx (m_opaque_sp.get());
 
     if (log)
         log->Printf ("SBThread(%p)::StepOut ()", exe_ctx.GetThreadPtr());
@@ -553,7 +584,7 @@ SBThread::StepOutOfFrame (lldb::SBFrame &sb_frame)
 {
     LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_API));
 
-    ExecutionContext exe_ctx (m_opaque_wp);
+    ExecutionContext exe_ctx (m_opaque_sp.get());
     StackFrameSP frame_sp (sb_frame.GetFrameSP());
     if (log)
     {
@@ -595,7 +626,7 @@ SBThread::StepInstruction (bool step_over)
 {
     LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_API));
 
-    ExecutionContext exe_ctx (m_opaque_wp);
+    ExecutionContext exe_ctx (m_opaque_sp.get());
 
 
     if (log)
@@ -624,7 +655,7 @@ SBThread::RunToAddress (lldb::addr_t addr)
 {
     LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_API));
 
-    ExecutionContext exe_ctx (m_opaque_wp);
+    ExecutionContext exe_ctx (m_opaque_sp.get());
 
     if (log)
         log->Printf ("SBThread(%p)::RunToAddress (addr=0x%llx)", exe_ctx.GetThreadPtr(), addr);
@@ -662,7 +693,7 @@ SBThread::StepOverUntil (lldb::SBFrame &sb_frame,
     LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_API));
     char path[PATH_MAX];
     
-    ExecutionContext exe_ctx (m_opaque_wp);    
+    ExecutionContext exe_ctx (m_opaque_sp.get());
     StackFrameSP frame_sp (sb_frame.GetFrameSP());
 
     if (log)
@@ -815,7 +846,7 @@ SBThread::StepOverUntil (lldb::SBFrame &sb_frame,
 bool
 SBThread::Suspend()
 {
-    ExecutionContext exe_ctx (m_opaque_wp);
+    ExecutionContext exe_ctx (m_opaque_sp.get());
     if (exe_ctx.HasThreadScope())
     {
         exe_ctx.GetThreadPtr()->SetResumeState (eStateSuspended);
@@ -827,7 +858,7 @@ SBThread::Suspend()
 bool
 SBThread::Resume ()
 {
-    ExecutionContext exe_ctx (m_opaque_wp);
+    ExecutionContext exe_ctx (m_opaque_sp.get());
     if (exe_ctx.HasThreadScope())
     {
         exe_ctx.GetThreadPtr()->SetResumeState (eStateRunning);
@@ -839,7 +870,7 @@ SBThread::Resume ()
 bool
 SBThread::IsSuspended()
 {
-    ExecutionContext exe_ctx (m_opaque_wp);
+    ExecutionContext exe_ctx (m_opaque_sp.get());
     if (exe_ctx.HasThreadScope())
         return exe_ctx.GetThreadPtr()->GetResumeState () == eStateSuspended;
     return false;
@@ -851,7 +882,7 @@ SBThread::GetProcess ()
 
     SBProcess sb_process;
     ProcessSP process_sp;
-    ExecutionContext exe_ctx (m_opaque_wp);
+    ExecutionContext exe_ctx (m_opaque_sp.get());
     if (exe_ctx.HasThreadScope())
     {
         // Have to go up to the target so we can get a shared pointer to our process...
@@ -876,11 +907,15 @@ SBThread::GetNumFrames ()
     LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_API));
 
     uint32_t num_frames = 0;
-    ExecutionContext exe_ctx (m_opaque_wp);
+    ExecutionContext exe_ctx (m_opaque_sp.get());
     if (exe_ctx.HasThreadScope())
     {
-        Mutex::Locker api_locker (exe_ctx.GetTargetPtr()->GetAPIMutex());
-        num_frames = exe_ctx.GetThreadPtr()->GetStackFrameCount();
+        Process::StopLocker stop_locker;
+        if (stop_locker.TryLock(&exe_ctx.GetProcessPtr()->GetRunLock()))
+        {
+            Mutex::Locker api_locker (exe_ctx.GetTargetPtr()->GetAPIMutex());
+            num_frames = exe_ctx.GetThreadPtr()->GetStackFrameCount();
+        }
     }
 
     if (log)
@@ -896,12 +931,16 @@ SBThread::GetFrameAtIndex (uint32_t idx)
 
     SBFrame sb_frame;
     StackFrameSP frame_sp;
-    ExecutionContext exe_ctx (m_opaque_wp);
+    ExecutionContext exe_ctx (m_opaque_sp.get());
     if (exe_ctx.HasThreadScope())
     {
-        Mutex::Locker api_locker (exe_ctx.GetTargetPtr()->GetAPIMutex());
-        frame_sp = exe_ctx.GetThreadPtr()->GetStackFrameAtIndex (idx);
-        sb_frame.SetFrameSP (frame_sp);
+        Process::StopLocker stop_locker;
+        if (stop_locker.TryLock(&exe_ctx.GetProcessPtr()->GetRunLock()))
+        {
+            Mutex::Locker api_locker (exe_ctx.GetTargetPtr()->GetAPIMutex());
+            frame_sp = exe_ctx.GetThreadPtr()->GetStackFrameAtIndex (idx);
+            sb_frame.SetFrameSP (frame_sp);
+        }
     }
 
     if (log)
@@ -922,12 +961,16 @@ SBThread::GetSelectedFrame ()
 
     SBFrame sb_frame;
     StackFrameSP frame_sp;
-    ExecutionContext exe_ctx (m_opaque_wp);
+    ExecutionContext exe_ctx (m_opaque_sp.get());
     if (exe_ctx.HasThreadScope())
     {
-        Mutex::Locker api_locker (exe_ctx.GetTargetPtr()->GetAPIMutex());
-        frame_sp = exe_ctx.GetThreadPtr()->GetSelectedFrame ();
-        sb_frame.SetFrameSP (frame_sp);
+        Process::StopLocker stop_locker;
+        if (stop_locker.TryLock(&exe_ctx.GetProcessPtr()->GetRunLock()))
+        {
+            Mutex::Locker api_locker (exe_ctx.GetTargetPtr()->GetAPIMutex());
+            frame_sp = exe_ctx.GetThreadPtr()->GetSelectedFrame ();
+            sb_frame.SetFrameSP (frame_sp);
+        }
     }
 
     if (log)
@@ -948,16 +991,20 @@ SBThread::SetSelectedFrame (uint32_t idx)
 
     SBFrame sb_frame;
     StackFrameSP frame_sp;
-    ExecutionContext exe_ctx (m_opaque_wp);
+    ExecutionContext exe_ctx (m_opaque_sp.get());
     if (exe_ctx.HasThreadScope())
     {
-        Mutex::Locker api_locker (exe_ctx.GetTargetPtr()->GetAPIMutex());
-        Thread *thread = exe_ctx.GetThreadPtr();
-        frame_sp = thread->GetStackFrameAtIndex (idx);
-        if (frame_sp)
+        Process::StopLocker stop_locker;
+        if (stop_locker.TryLock(&exe_ctx.GetProcessPtr()->GetRunLock()))
         {
-            thread->SetSelectedFrame (frame_sp.get());
-            sb_frame.SetFrameSP (frame_sp);
+            Mutex::Locker api_locker (exe_ctx.GetTargetPtr()->GetAPIMutex());
+            Thread *thread = exe_ctx.GetThreadPtr();
+            frame_sp = thread->GetStackFrameAtIndex (idx);
+            if (frame_sp)
+            {
+                thread->SetSelectedFrame (frame_sp.get());
+                sb_frame.SetFrameSP (frame_sp);
+            }
         }
     }
 
@@ -975,13 +1022,13 @@ SBThread::SetSelectedFrame (uint32_t idx)
 bool
 SBThread::operator == (const SBThread &rhs) const
 {
-    return m_opaque_wp.lock().get() == rhs.m_opaque_wp.lock().get();
+    return m_opaque_sp->GetThreadSP().get() == rhs.m_opaque_sp->GetThreadSP().get();
 }
 
 bool
 SBThread::operator != (const SBThread &rhs) const
 {
-    return m_opaque_wp.lock().get() != rhs.m_opaque_wp.lock().get();
+    return m_opaque_sp->GetThreadSP().get() != rhs.m_opaque_sp->GetThreadSP().get();
 }
 
 bool
@@ -989,7 +1036,7 @@ SBThread::GetDescription (SBStream &description) const
 {
     Stream &strm = description.ref();
 
-    ExecutionContext exe_ctx (m_opaque_wp);
+    ExecutionContext exe_ctx (m_opaque_sp.get());
     if (exe_ctx.HasThreadScope())
     {
         strm.Printf("SBThread: tid = 0x%4.4llx", exe_ctx.GetThreadPtr()->GetID());