Remove option to disable the table-driven parser in protoc.

It is now the default and only codegen parser implementation.

Also, remove the newly dead code.

PiperOrigin-RevId: 556873863

src/google/protobuf/compiler/cpp/file.cc

@@ -656,8 +656,7 @@ void FileGenerator::GenerateSourceIncludes(io::Printer* p) {
     IncludeFile("third_party/protobuf/wire_format.h", p);
   }
 
-  if (HasGeneratedMethods(file_, options_) &&
-      options_.tctable_mode != Options::kTCTableNever) {
+  if (HasGeneratedMethods(file_, options_)) {
     IncludeFile("third_party/protobuf/generated_message_tctable_impl.h", p);
   }
 
@@ -703,8 +702,7 @@ void FileGenerator::GenerateSourcePrelude(io::Printer* p) {
     namespace _pbi = ::$proto_ns$::internal;
   )cc");
 
-  if (HasGeneratedMethods(file_, options_) &&
-      options_.tctable_mode != Options::kTCTableNever) {
+  if (HasGeneratedMethods(file_, options_)) {
     p->Emit(R"cc(
       namespace _fl = ::$proto_ns$::internal::field_layout;
     )cc");
@@ -1554,8 +1552,7 @@ void FileGenerator::GenerateLibraryIncludes(io::Printer* p) {
   if (HasSimpleBaseClasses(file_, options_)) {
     IncludeFile("third_party/protobuf/generated_message_bases.h", p);
   }
-  if (HasGeneratedMethods(file_, options_) &&
-      options_.tctable_mode != Options::kTCTableNever) {
+  if (HasGeneratedMethods(file_, options_)) {
     IncludeFile("third_party/protobuf/generated_message_tctable_decl.h", p);
   }
   IncludeFile("third_party/protobuf/generated_message_util.h", p);

src/google/protobuf/compiler/cpp/generator.cc

@@ -191,16 +191,6 @@ bool CppGenerator::Generate(const FileDescriptor* file,
       } while (pos < value.size());
     } else if (key == "force_eagerly_verified_lazy") {
       file_options.force_eagerly_verified_lazy = true;
-    } else if (key == "experimental_tail_call_table_mode") {
-      if (value == "never") {
-        file_options.tctable_mode = Options::kTCTableNever;
-      } else if (value == "always") {
-        file_options.tctable_mode = Options::kTCTableAlways;
-      } else {
-        *error = absl::StrCat(
-            "Unknown value for experimental_tail_call_table_mode: ", value);
-        return false;
-      }
     } else if (key == "experimental_strip_nonfunctional_codegen") {
       file_options.strip_nonfunctional_codegen = true;
     } else {

src/google/protobuf/compiler/cpp/helpers.h

@@ -834,10 +834,6 @@ class PROTOC_EXPORT Formatter {
     vars_[key] = ToString(value);
   }
 
-  void AddMap(const absl::flat_hash_map<absl::string_view, std::string>& vars) {
-    for (const auto& keyval : vars) vars_[keyval.first] = keyval.second;
-  }
-
   template <typename... Args>
   void operator()(const char* format, const Args&... args) const {
     printer_->FormatInternal({ToString(args)...}, vars_, format);
@@ -868,17 +864,6 @@ class PROTOC_EXPORT Formatter {
     return ScopedIndenter(this);
   }
 
-  class PROTOC_EXPORT SaveState {
-   public:
-    explicit SaveState(Formatter* format)
-        : format_(format), vars_(format->vars_) {}
-    ~SaveState() { format_->vars_.swap(vars_); }
-
-   private:
-    Formatter* format_;
-    absl::flat_hash_map<absl::string_view, std::string> vars_;
-  };
-
  private:
   io::Printer* printer_;
   absl::flat_hash_map<absl::string_view, std::string> vars_;

src/google/protobuf/compiler/cpp/options.h

@@ -67,7 +67,6 @@ struct Options {
   std::string annotation_guard_name;
   FieldListenerOptions field_listener_options;
   EnforceOptimizeMode enforce_mode = EnforceOptimizeMode::kNoEnforcement;
-  enum { kTCTableNever, kTCTableAlways } tctable_mode = kTCTableAlways;
   int num_cc_files = 0;
   bool safe_boundary_check = false;
   bool proto_h = false;