Index: lldb/unittests/Symbol/CMakeLists.txt
===================================================================
--- lldb/unittests/Symbol/CMakeLists.txt
+++ lldb/unittests/Symbol/CMakeLists.txt
@@ -1,4 +1,5 @@
 add_lldb_unittest(SymbolTests
+  CompilerTypeTest.cpp
   LocateSymbolFileTest.cpp
   PostfixExpressionTest.cpp
   TestClangASTContext.cpp
@@ -10,6 +11,7 @@
     lldbHost
     lldbSymbol
     lldbUtilityHelpers
+    lldbSymbolHelpers
     lldbPluginObjectFileELF
     lldbPluginObjectFileMachO
     lldbPluginSymbolFileDWARF
Index: lldb/unittests/Symbol/CompilerTypeTest.cpp
===================================================================
--- /dev/null
+++ lldb/unittests/Symbol/CompilerTypeTest.cpp
@@ -0,0 +1,45 @@
+//===-- CompilerTypeTest.cpp -------------------------==---------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Symbol/CompilerType.h"
+#include "TestingSupport/Symbol/FakeTypeSystem.h"
+
+#include "gtest/gtest.h"
+
+using namespace lldb_private;
+
+namespace {
+struct TestTypeSystem : public lldb_private::FakeTypeSystem {
+  void *GetOpaqueValidType() { return &valid_type_storage; }
+
+private:
+  int valid_type_storage;
+};
+} // namespace
+
+TEST(CompilerType, DefaultConstructor) {
+  CompilerType type;
+  EXPECT_EQ(nullptr, type.GetTypeSystem());
+  EXPECT_EQ(nullptr, type.GetOpaqueQualType());
+}
+
+TEST(CompilerType, Constructor) {
+  TestTypeSystem ts;
+  CompilerType type(&ts, ts.GetOpaqueValidType());
+  EXPECT_EQ(&ts, type.GetTypeSystem());
+  EXPECT_EQ(ts.GetOpaqueValidType(), type.GetOpaqueQualType());
+}
+
+TEST(CompilerType, Clear) {
+  TestTypeSystem ts;
+  CompilerType type(&ts, ts.GetOpaqueValidType());
+
+  type.Clear();
+  EXPECT_EQ(nullptr, type.GetTypeSystem());
+  EXPECT_EQ(nullptr, type.GetOpaqueQualType());
+}
Index: lldb/unittests/TestingSupport/CMakeLists.txt
===================================================================
--- lldb/unittests/TestingSupport/CMakeLists.txt
+++ lldb/unittests/TestingSupport/CMakeLists.txt
@@ -11,3 +11,5 @@
     ObjectYAML
   )
 include_directories(${LLVM_MAIN_SRC_DIR}/utils/unittest/googletest/include)
+
+add_subdirectory(Symbol)
Index: lldb/unittests/TestingSupport/Symbol/CMakeLists.txt
===================================================================
--- /dev/null
+++ lldb/unittests/TestingSupport/Symbol/CMakeLists.txt
@@ -0,0 +1,11 @@
+set_property(DIRECTORY PROPERTY EXCLUDE_FROM_ALL ON)
+add_lldb_library(lldbSymbolHelpers
+  FakeTypeSystem.cpp
+
+  LINK_LIBS
+    lldbSymbol
+
+  LINK_COMPONENTS
+    Support
+  )
+include_directories(${LLVM_MAIN_SRC_DIR}/utils/unittest/googletest/include)
Index: lldb/unittests/TestingSupport/Symbol/FakeTypeSystem.h
===================================================================
--- /dev/null
+++ lldb/unittests/TestingSupport/Symbol/FakeTypeSystem.h
@@ -0,0 +1,408 @@
+//===-- FakeTypeSystem.h -----------------------------==---------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Symbol/Type.h"
+#include "lldb/Symbol/TypeSystem.h"
+
+namespace lldb_private {
+/// A TypeSystem implementation that throws an error if any of its methods are
+/// called. Should be used as a base class for new TypeSystem subclasses in
+/// tests.
+struct FakeTypeSystem : public TypeSystem {
+  // llvm casting support
+  static char ID;
+  bool isA(const void *ClassID) const override { return ClassID == &ID; }
+  static bool classof(const TypeSystem *ts) { return ts->isA(&ID); }
+
+#define UNIMPLEMENTED_METHOD llvm_unreachable("not implemented")
+
+  ConstString GetPluginName() override { UNIMPLEMENTED_METHOD; }
+
+  uint32_t GetPluginVersion() override { UNIMPLEMENTED_METHOD; }
+
+  ConstString DeclGetName(void *opaque_decl) override { UNIMPLEMENTED_METHOD; }
+
+  CompilerType GetTypeForDecl(void *opaque_decl) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool DeclContextIsStructUnionOrClass(void *opaque_decl_ctx) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  ConstString DeclContextGetName(void *opaque_decl_ctx) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  ConstString DeclContextGetScopeQualifiedName(void *opaque_decl_ctx) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool
+  DeclContextIsClassMethod(void *opaque_decl_ctx,
+                           lldb::LanguageType *language_ptr,
+                           bool *is_instance_method_ptr,
+                           ConstString *language_object_name_ptr) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool DeclContextIsContainedInLookup(void *opaque_decl_ctx,
+                                      void *other_opaque_decl_ctx) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool IsArrayType(lldb::opaque_compiler_type_t type,
+                   CompilerType *element_type, uint64_t *size,
+                   bool *is_incomplete) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool IsAggregateType(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool IsCharType(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool IsCompleteType(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool IsDefined(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool IsFloatingPointType(lldb::opaque_compiler_type_t type, uint32_t &count,
+                           bool &is_complex) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool IsFunctionType(lldb::opaque_compiler_type_t type,
+                      bool *is_variadic_ptr) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  size_t
+  GetNumberOfFunctionArguments(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  CompilerType GetFunctionArgumentAtIndex(lldb::opaque_compiler_type_t type,
+                                          const size_t index) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool IsFunctionPointerType(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool IsBlockPointerType(lldb::opaque_compiler_type_t type,
+                          CompilerType *function_pointer_type_ptr) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool IsIntegerType(lldb::opaque_compiler_type_t type,
+                     bool &is_signed) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool IsPossibleDynamicType(lldb::opaque_compiler_type_t type,
+                             CompilerType *target_type, bool check_cplusplus,
+                             bool check_objc) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool IsPointerType(lldb::opaque_compiler_type_t type,
+                     CompilerType *pointee_type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool IsScalarType(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool IsVoidType(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool CanPassInRegisters(const CompilerType &type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool SupportsLanguage(lldb::LanguageType language) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool GetCompleteType(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  uint32_t GetPointerByteSize() override { UNIMPLEMENTED_METHOD; }
+
+  ConstString GetTypeName(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  uint32_t
+  GetTypeInfo(lldb::opaque_compiler_type_t type,
+              CompilerType *pointee_or_element_compiler_type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  lldb::LanguageType
+  GetMinimumLanguage(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  lldb::TypeClass GetTypeClass(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  CompilerType GetArrayElementType(lldb::opaque_compiler_type_t type,
+                                   uint64_t *stride) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  CompilerType GetCanonicalType(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  int GetFunctionArgumentCount(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  CompilerType GetFunctionArgumentTypeAtIndex(lldb::opaque_compiler_type_t type,
+                                              size_t idx) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  CompilerType
+  GetFunctionReturnType(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  size_t GetNumMemberFunctions(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  TypeMemberFunctionImpl
+  GetMemberFunctionAtIndex(lldb::opaque_compiler_type_t type,
+                           size_t idx) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  CompilerType GetPointeeType(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  CompilerType GetPointerType(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  const llvm::fltSemantics &GetFloatTypeSemantics(size_t byte_size) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  llvm::Optional<uint64_t>
+  GetBitSize(lldb::opaque_compiler_type_t type,
+             ExecutionContextScope *exe_scope) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  lldb::Encoding GetEncoding(lldb::opaque_compiler_type_t type,
+                             uint64_t &count) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  lldb::Format GetFormat(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  uint32_t GetNumChildren(lldb::opaque_compiler_type_t type,
+                          bool omit_empty_base_classes,
+                          const ExecutionContext *exe_ctx) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  lldb::BasicType
+  GetBasicTypeEnumeration(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  uint32_t GetNumFields(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  CompilerType GetFieldAtIndex(lldb::opaque_compiler_type_t type, size_t idx,
+                               std::string &name, uint64_t *bit_offset_ptr,
+                               uint32_t *bitfield_bit_size_ptr,
+                               bool *is_bitfield_ptr) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  uint32_t GetNumDirectBaseClasses(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  uint32_t
+  GetNumVirtualBaseClasses(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  CompilerType GetDirectBaseClassAtIndex(lldb::opaque_compiler_type_t type,
+                                         size_t idx,
+                                         uint32_t *bit_offset_ptr) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  CompilerType GetVirtualBaseClassAtIndex(lldb::opaque_compiler_type_t type,
+                                          size_t idx,
+                                          uint32_t *bit_offset_ptr) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  CompilerType GetChildCompilerTypeAtIndex(
+      lldb::opaque_compiler_type_t type, ExecutionContext *exe_ctx, size_t idx,
+      bool transparent_pointers, bool omit_empty_base_classes,
+      bool ignore_array_bounds, std::string &child_name,
+      uint32_t &child_byte_size, int32_t &child_byte_offset,
+      uint32_t &child_bitfield_bit_size, uint32_t &child_bitfield_bit_offset,
+      bool &child_is_base_class, bool &child_is_deref_of_parent,
+      ValueObject *valobj, uint64_t &language_flags) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  uint32_t GetIndexOfChildWithName(lldb::opaque_compiler_type_t type,
+                                   const char *name,
+                                   bool omit_empty_base_classes) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  size_t
+  GetIndexOfChildMemberWithName(lldb::opaque_compiler_type_t type,
+                                const char *name, bool omit_empty_base_classes,
+                                std::vector<uint32_t> &child_indexes) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+#ifndef NDEBUG
+  /// Convenience LLVM-style dump method for use in the debugger only.
+  LLVM_DUMP_METHOD void dump(lldb::opaque_compiler_type_t type) const override {
+    UNIMPLEMENTED_METHOD;
+  }
+#endif
+
+  void DumpValue(lldb::opaque_compiler_type_t type, ExecutionContext *exe_ctx,
+                 Stream *s, lldb::Format format, const DataExtractor &data,
+                 lldb::offset_t data_offset, size_t data_byte_size,
+                 uint32_t bitfield_bit_size, uint32_t bitfield_bit_offset,
+                 bool show_types, bool show_summary, bool verbose,
+                 uint32_t depth) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool DumpTypeValue(lldb::opaque_compiler_type_t type, Stream *s,
+                     lldb::Format format, const DataExtractor &data,
+                     lldb::offset_t data_offset, size_t data_byte_size,
+                     uint32_t bitfield_bit_size, uint32_t bitfield_bit_offset,
+                     ExecutionContextScope *exe_scope) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  void DumpTypeDescription(lldb::opaque_compiler_type_t type) override {}
+
+  void DumpTypeDescription(lldb::opaque_compiler_type_t type,
+                           Stream *s) override {}
+
+  bool IsRuntimeGeneratedType(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  void DumpSummary(lldb::opaque_compiler_type_t type, ExecutionContext *exe_ctx,
+                   Stream *s, const DataExtractor &data,
+                   lldb::offset_t data_offset, size_t data_byte_size) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool IsPointerOrReferenceType(lldb::opaque_compiler_type_t type,
+                                CompilerType *pointee_type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  unsigned GetTypeQualifiers(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool IsCStringType(lldb::opaque_compiler_type_t type,
+                     uint32_t &length) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  llvm::Optional<size_t>
+  GetTypeBitAlign(lldb::opaque_compiler_type_t type,
+                  ExecutionContextScope *exe_scope) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  CompilerType GetBasicTypeFromAST(lldb::BasicType basic_type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  CompilerType GetBuiltinTypeForEncodingAndBitSize(lldb::Encoding encoding,
+                                                   size_t bit_size) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool IsBeingDefined(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+  bool IsConst(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  uint32_t IsHomogeneousAggregate(lldb::opaque_compiler_type_t type,
+                                  CompilerType *base_type_ptr) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool IsPolymorphicClass(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool IsTypedefType(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  CompilerType GetTypedefedType(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool IsVectorType(lldb::opaque_compiler_type_t type,
+                    CompilerType *element_type, uint64_t *size) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  CompilerType
+  GetFullyUnqualifiedType(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  CompilerType GetNonReferenceType(lldb::opaque_compiler_type_t type) override {
+    UNIMPLEMENTED_METHOD;
+  }
+
+  bool IsReferenceType(lldb::opaque_compiler_type_t type,
+                       CompilerType *pointee_type, bool *is_rvalue) override {
+    UNIMPLEMENTED_METHOD;
+  }
+};
+
+#undef UNIMPLEMENTED_METHOD
+
+} // namespace lldb_private
Index: lldb/unittests/TestingSupport/Symbol/FakeTypeSystem.cpp
===================================================================
--- /dev/null
+++ lldb/unittests/TestingSupport/Symbol/FakeTypeSystem.cpp
@@ -0,0 +1,11 @@
+//===-- FakeTypeSystem.cpp ---------------------------==---------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "FakeTypeSystem.h"
+
+char lldb_private::FakeTypeSystem::ID;