Index: lldb/include/lldb/Symbol/CompilerType.h
===================================================================
--- lldb/include/lldb/Symbol/CompilerType.h
+++ lldb/include/lldb/Symbol/CompilerType.h
@@ -66,10 +66,10 @@
   /// Tests.
   /// \{
   explicit operator bool() const {
-    return m_type != nullptr && m_type_system != nullptr;
+    return IsValid();
   }
 
-  bool IsValid() const { return m_type != nullptr && m_type_system != nullptr; }
+  bool IsValid() const;
 
   bool IsArrayType(CompilerType *element_type = nullptr,
                    uint64_t *size = nullptr,
Index: lldb/include/lldb/Symbol/TypeSystem.h
===================================================================
--- lldb/include/lldb/Symbol/TypeSystem.h
+++ lldb/include/lldb/Symbol/TypeSystem.h
@@ -21,6 +21,7 @@
 #include "llvm/Support/Error.h"
 
 #include "lldb/Core/PluginInterface.h"
+#include "lldb/Core/ThreadSafeDenseMap.h"
 #include "lldb/Expression/Expression.h"
 #include "lldb/Symbol/CompilerDecl.h"
 #include "lldb/Symbol/CompilerDeclContext.h"
@@ -74,7 +75,8 @@
 class TypeSystem : public PluginInterface {
 public:
   // Constructors and Destructors
-  ~TypeSystem() override;
+  TypeSystem();
+  ~TypeSystem() = default;
 
   // LLVM RTTI support
   virtual bool isA(const void *ClassID) const = 0;
@@ -87,7 +89,7 @@
 
   // Free up any resources associated with this TypeSystem.  Done before
   // removing all the TypeSystems from the TypeSystemMap.
-  virtual void Finalize() {}
+  virtual void Finalize();
 
   virtual DWARFASTParser *GetDWARFParser() { return nullptr; }
   virtual PDBASTParser *GetPDBParser() { return nullptr; }
@@ -558,6 +560,12 @@
       llvm::Optional<CreateCallback> create_callback = llvm::None);
 };
 
+using TypeSystemSet =
+    ThreadSafeDenseMap<TypeSystem *, bool, std::recursive_mutex>;
+/// A set of type systems that have been deleted and can no longer be accessed.
+/// The bool value is unused.
+TypeSystemSet &GetTypeSystemGraveyard();
+  
 } // namespace lldb_private
 
 #endif // LLDB_SYMBOL_TYPESYSTEM_H
Index: lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
===================================================================
--- lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
+++ lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
@@ -552,7 +552,8 @@
 }
 
 TypeSystemClang::TypeSystemClang(llvm::StringRef name,
-                                 llvm::Triple target_triple) {
+                                 llvm::Triple target_triple)
+    : TypeSystem() {
   m_display_name = name.str();
   if (!target_triple.str().empty())
     SetTargetTriple(target_triple.str());
@@ -562,7 +563,8 @@
 }
 
 TypeSystemClang::TypeSystemClang(llvm::StringRef name,
-                                 ASTContext &existing_ctxt) {
+                                 ASTContext &existing_ctxt)
+    : TypeSystem() {
   m_display_name = name.str();
   SetTargetTriple(existing_ctxt.getTargetInfo().getTriple().str());
 
@@ -661,6 +663,7 @@
   m_diagnostics_engine_up.reset();
   m_source_manager_up.reset();
   m_language_options_up.reset();
+  TypeSystem::Finalize();
 }
 
 void TypeSystemClang::setSema(Sema *s) {
Index: lldb/source/Symbol/CompilerType.cpp
===================================================================
--- lldb/source/Symbol/CompilerType.cpp
+++ lldb/source/Symbol/CompilerType.cpp
@@ -11,11 +11,13 @@
 #include "lldb/Core/Debugger.h"
 #include "lldb/Core/StreamFile.h"
 #include "lldb/Symbol/Type.h"
+#include "lldb/Symbol/TypeSystem.h"
 #include "lldb/Target/ExecutionContext.h"
 #include "lldb/Target/Process.h"
 #include "lldb/Utility/ConstString.h"
 #include "lldb/Utility/DataBufferHeap.h"
 #include "lldb/Utility/DataExtractor.h"
+#include "lldb/Utility/LLDBAssert.h"
 #include "lldb/Utility/Scalar.h"
 #include "lldb/Utility/Stream.h"
 #include "lldb/Utility/StreamString.h"
@@ -26,6 +28,17 @@
 using namespace lldb;
 using namespace lldb_private;
 
+bool CompilerType::IsValid() const {
+  if (!m_type || !m_type_system)
+    return false;
+  bool unused;
+  if (GetTypeSystemGraveyard().Lookup(m_type_system, unused)) {
+    lldbassert(false && "CompilerType belongs to deleted Typesystem");
+    return false;
+  }
+  return true;
+}
+
 // Tests
 
 bool CompilerType::IsAggregateType() const {
Index: lldb/source/Symbol/TypeSystem.cpp
===================================================================
--- lldb/source/Symbol/TypeSystem.cpp
+++ lldb/source/Symbol/TypeSystem.cpp
@@ -17,6 +17,12 @@
 using namespace lldb_private;
 using namespace lldb;
 
+TypeSystemSet &lldb_private::GetTypeSystemGraveyard() {
+  // Intentionally leaked to avoid C++ destructor ordering issue.
+  static TypeSystemSet *g_typesystem_graveyard = new TypeSystemSet();
+  return *g_typesystem_graveyard;
+}
+
 /// A 64-bit SmallBitVector is only small up to 64-7 bits, and the
 /// setBitsInMask interface wants to write full bytes.
 static const size_t g_num_small_bitvector_bits = 64 - 8;
@@ -35,7 +41,11 @@
 bool LanguageSet::Empty() const { return bitvector.none(); }
 bool LanguageSet::operator[](unsigned i) const { return bitvector[i]; }
 
-TypeSystem::~TypeSystem() = default;
+TypeSystem::TypeSystem() {
+  // Remove this pointer from the graveyard in case it got reused.
+  GetTypeSystemGraveyard().Erase(this);
+}
+void TypeSystem::Finalize() { GetTypeSystemGraveyard().Insert(this, false); }
 
 static lldb::TypeSystemSP CreateInstanceHelper(lldb::LanguageType language,
                                                Module *module, Target *target) {
Index: lldb/unittests/Symbol/TestTypeSystemClang.cpp
===================================================================
--- lldb/unittests/Symbol/TestTypeSystemClang.cpp
+++ lldb/unittests/Symbol/TestTypeSystemClang.cpp
@@ -29,6 +29,7 @@
   void SetUp() override {
     m_ast.reset(
         new TypeSystemClang("test ASTContext", HostInfo::GetTargetTriple()));
+    GetTypeSystemGraveyard().Erase(m_ast.get());
   }
 
   void TearDown() override { m_ast.reset(); }