[lldb][NFC] Move TypeSystem RTTI to static variable to remove swift reference

lldb/include/lldb/Symbol/ClangASTContext.h

@@ -41,15 +41,17 @@ namespace lldb_private {
 class Declaration;
 
 class ClangASTContext : public TypeSystem {
+  // LLVM RTTI support
+  static char ID;
+
 public:
   typedef void (*CompleteTagDeclCallback)(void *baton, clang::TagDecl *);
   typedef void (*CompleteObjCInterfaceDeclCallback)(void *baton,
                                                     clang::ObjCInterfaceDecl *);
 
   // llvm casting support
-  static bool classof(const TypeSystem *ts) {
-    return ts->getKind() == TypeSystem::eKindClang;
-  }
+  bool isA(const void *ClassID) const override { return ClassID == &ID; }
+  static bool classof(const TypeSystem *ts) { return ts->isA(&ID); }
 
   // Constructors and Destructors
   explicit ClangASTContext(llvm::StringRef triple = "");

lldb/include/lldb/Symbol/TypeSystem.h

@@ -52,47 +52,11 @@ struct LanguageSet {
 /// Interface for representing the Type Systems in different languages.
 class TypeSystem : public PluginInterface {
 public:
-  // Intrusive type system that allows us to use llvm casting.
-  //
-  // To add a new type system:
-  //
-  // 1 - Add a new enumeration for llvm casting below for your TypeSystem
-  //     subclass, here we will use eKindFoo
-  //
-  // 2 - Your TypeSystem subclass will inherit from TypeSystem and needs
-  //     to implement a static classof() function that returns your
-  //     enumeration:
-  //
-  //    class Foo : public lldb_private::TypeSystem
-  //    {
-  //        static bool classof(const TypeSystem *ts)
-  //        {
-  //            return ts->getKind() == TypeSystem::eKindFoo;
-  //        }
-  //    };
-  //
-  // 3 - Contruct your TypeSystem subclass with the enumeration from below
-  //
-  //    Foo() :
-  //        TypeSystem(TypeSystem::eKindFoo),
-  //        ...
-  //    {
-  //    }
-  //
-  // Then you can use the llvm casting on any "TypeSystem *" to get an instance
-  // of your subclass.
-  enum LLVMCastKind {
-    eKindClang,
-    eKindSwift,
-    kNumKinds
-  };
-
   // Constructors and Destructors
-  TypeSystem(LLVMCastKind kind);
-
   ~TypeSystem() override;
 
-  LLVMCastKind getKind() const { return m_kind; }
+  // LLVM RTTI support
+  virtual bool isA(const void *ClassID) const = 0;
 
   static lldb::TypeSystemSP CreateInstance(lldb::LanguageType language,
                                            Module *module);
@@ -493,8 +457,7 @@ public:
   virtual bool IsMeaninglessWithoutDynamicResolution(void *type);
 
 protected:
-  const LLVMCastKind m_kind; // Support for llvm casting
-  SymbolFile *m_sym_file;
+  SymbolFile *m_sym_file = nullptr;
 };
 
 class TypeSystemMap {

lldb/source/Symbol/ClangASTContext.cpp

@@ -337,6 +337,8 @@ static ClangASTMap &GetASTMap() {
   return *g_map_ptr;
 }
 
+char ClangASTContext::ID;
+
 bool ClangASTContext::IsOperator(llvm::StringRef name,
                                  clang::OverloadedOperatorKind &op_kind) {
   // All operators have to start with "operator".
@@ -522,8 +524,7 @@ static void ParseLangArgs(LangOptions &Opts, InputKind IK, const char *triple) {
   Opts.NoInlineDefine = !Opt;
 }
 
-ClangASTContext::ClangASTContext(llvm::StringRef target_triple)
-    : TypeSystem(TypeSystem::eKindClang) {
+ClangASTContext::ClangASTContext(llvm::StringRef target_triple) {
   if (!target_triple.empty())
     SetTargetTriple(target_triple);
   // The caller didn't pass an ASTContext so create a new one for this
@@ -531,16 +532,14 @@ ClangASTContext::ClangASTContext(llvm::StringRef target_triple)
   CreateASTContext();
 }
 
-ClangASTContext::ClangASTContext(ArchSpec arch)
-    : TypeSystem(TypeSystem::eKindClang) {
+ClangASTContext::ClangASTContext(ArchSpec arch) {
   SetTargetTriple(arch.GetTriple().str());
   // The caller didn't pass an ASTContext so create a new one for this
   // ClangASTContext.
   CreateASTContext();
 }
 
-ClangASTContext::ClangASTContext(ASTContext &existing_ctxt)
-  : TypeSystem(TypeSystem::eKindClang) {
+ClangASTContext::ClangASTContext(ASTContext &existing_ctxt) {
   SetTargetTriple(existing_ctxt.getTargetInfo().getTriple().str());
 
   m_ast_up.reset(&existing_ctxt);

lldb/source/Symbol/CompilerDecl.cpp

@@ -7,13 +7,14 @@
 //===----------------------------------------------------------------------===//
 
 #include "lldb/Symbol/CompilerDecl.h"
+#include "lldb/Symbol/ClangASTContext.h"
 #include "lldb/Symbol/CompilerDeclContext.h"
 #include "lldb/Symbol/TypeSystem.h"
 
 using namespace lldb_private;
 
 bool CompilerDecl::IsClang() const {
-  return IsValid() && m_type_system->getKind() == TypeSystem::eKindClang;
+  return IsValid() && llvm::isa<ClangASTContext>(m_type_system);
 }
 
 ConstString CompilerDecl::GetName() const {

lldb/source/Symbol/CompilerDeclContext.cpp

@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "lldb/Symbol/CompilerDeclContext.h"
+#include "lldb/Symbol/ClangASTContext.h"
 #include "lldb/Symbol/CompilerDecl.h"
 #include "lldb/Symbol/TypeSystem.h"
 #include <vector>
@@ -24,7 +25,7 @@ CompilerDeclContext::FindDeclByName(ConstString name,
 }
 
 bool CompilerDeclContext::IsClang() const {
-  return IsValid() && m_type_system->getKind() == TypeSystem::eKindClang;
+  return IsValid() && llvm::isa<ClangASTContext>(m_type_system);
 }
 
 ConstString CompilerDeclContext::GetName() const {

lldb/source/Symbol/TypeSystem.cpp

@@ -43,8 +43,6 @@ size_t LanguageSet::Size() const { return bitvector.count(); }
 bool LanguageSet::Empty() const { return bitvector.none(); }
 bool LanguageSet::operator[](unsigned i) const { return bitvector[i]; }
 
-TypeSystem::TypeSystem(LLVMCastKind kind) : m_kind(kind), m_sym_file(nullptr) {}
-
 TypeSystem::~TypeSystem() {}
 
 static lldb::TypeSystemSP CreateInstanceHelper(lldb::LanguageType language,