🍒 [lldb] Fix ThreadPlanStepOut::DoPlanExplainsStop inspection of BreakpointSite (#169799)

lldb/include/lldb/Breakpoint/BreakpointSite.h

@@ -156,6 +156,10 @@ class BreakpointSite : public std::enable_shared_from_this<BreakpointSite>,
   ///     would be valid for this thread, false otherwise.
   bool ValidForThisThread(Thread &thread);
 
+  /// Returns true if at least one constituent is both public and valid for
+  /// `thread`.
+  bool ContainsUserBreakpointForThread(Thread &thread);
+
   /// Print a description of this breakpoint site to the stream \a s.
   /// GetDescription tells you about the breakpoint site's constituents. Use
   /// BreakpointSite::Dump(Stream *) to get information about the breakpoint

lldb/source/Breakpoint/BreakpointSite.cpp

@@ -168,6 +168,22 @@ bool BreakpointSite::ValidForThisThread(Thread &thread) {
   return m_constituents.ValidForThisThread(thread);
 }
 
+bool BreakpointSite::ContainsUserBreakpointForThread(Thread &thread) {
+  if (ThreadSP backed_thread = thread.GetBackedThread())
+    return ContainsUserBreakpointForThread(*backed_thread);
+
+  std::lock_guard<std::recursive_mutex> guard(m_constituents_mutex);
+  for (const BreakpointLocationSP &bp_loc :
+       m_constituents.BreakpointLocations()) {
+    const Breakpoint &bp = bp_loc->GetBreakpoint();
+    if (bp.IsInternal())
+      continue;
+    if (bp_loc->ValidForThisThread(thread))
+      return true;
+  }
+  return false;
+}
+
 void BreakpointSite::BumpHitCounts() {
   std::lock_guard<std::recursive_mutex> guard(m_constituents_mutex);
   for (BreakpointLocationSP loc_sp : m_constituents.BreakpointLocations()) {

lldb/source/Target/ThreadPlanStepOut.cpp

@@ -390,13 +390,10 @@ bool ThreadPlanStepOut::DoPlanExplainsStop(Event *event_ptr) {
           }
         }
 
-        // If there was only one owner, then we're done.  But if we also hit
-        // some user breakpoint on our way out, we should mark ourselves as
-        // done, but also not claim to explain the stop, since it is more
-        // important to report the user breakpoint than the step out
-        // completion.
-
-        if (site_sp->GetNumberOfConstituents() == 1)
+        // If the thread also hit a user breakpoint on its way out, the plan is
+        // done but should not claim to explain the stop. It is more important
+        // to report the user breakpoint than the step out completion.
+        if (!site_sp->ContainsUserBreakpointForThread(GetThread()))
           return true;
       }
       return false;