[LLDB] Fix for synthetic children memory leak

The lifetime of a ValueObject and all its derivative ValueObjects (children, clones, etc.) is managed by a ClusterManager. These objects are only destroyed when every shared pointer to any of the managed objects in the cluster is destroyed. This means that no object in the cluster can store a shared pointer to another object in the cluster without creating a memory leak of the entire cluster. However, some of the synthetic children front-end implementations do exactly this; this patch fixes that.

Differential Revision: https://reviews.llvm.org/D68641

llvm-svn: 374195

1 files changed, 8 insertions, 3 deletions

diff --git a/lldb/source/Plugins/Language/CPlusPlus/LibStdcppTuple.cpp b/lldb/source/Plugins/Language/CPlusPlus/LibStdcppTuple.cpp
index 66624e5beb6..15bf7f8cf1d 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/LibStdcppTuple.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/LibStdcppTuple.cpp
@@ -37,7 +37,12 @@ public:
   size_t GetIndexOfChildWithName(ConstString name) override;
 
 private:
-  std::vector<ValueObjectSP> m_members;
+  // The lifetime of a ValueObject and all its derivative ValueObjects
+  // (children, clones, etc.) is managed by a ClusterManager. These
+  // objects are only destroyed when every shared pointer to any of them
+  // is destroyed, so we must not store a shared pointer to any ValueObject
+  // derived from our backend ValueObject (since we're in the same cluster).
+  std::vector<ValueObject*> m_members;
 };
 
 } // end of anonymous namespace
@@ -72,7 +77,7 @@ bool LibStdcppTupleSyntheticFrontEnd::Update() {
         if (value_sp) {
           StreamString name;
           name.Printf("[%zd]", m_members.size());
-          m_members.push_back(value_sp->Clone(ConstString(name.GetString())));
+          m_members.push_back(value_sp->Clone(ConstString(name.GetString())).get());
         }
       }
     }
@@ -86,7 +91,7 @@ bool LibStdcppTupleSyntheticFrontEnd::MightHaveChildren() { return true; }
 lldb::ValueObjectSP
 LibStdcppTupleSyntheticFrontEnd::GetChildAtIndex(size_t idx) {
   if (idx < m_members.size())
-    return m_members[idx];
+    return m_members[idx]->GetSP();
   return lldb::ValueObjectSP();
 }