Audit and fixups for GCC and Clang (#7212)

Added (for compiler versions that support it):
-Wmissing-declarations
-Wzero-as-null-pointer-constant

Then, fixes to problems identified by the extra warnings
Tested only on GCC 9.4.0

Adjusted the CPP code generator to output nullptr where appropriate,
to satisfy -Wzero-as-null-pointer-constant

Added a lot of 'static' declarations in front of functions,
to satisfy -Wmissing-declarations,
and wrap static function defs in anonymous namespaces.

There are advantages to both anonymous namespaces and static,
it seems that marking a function as static will not publish the name in
the symbol table at all, thus giving the linker less work to do.

6 files changed, 93 insertions, 58 deletions

diff --git a/grpc/src/compiler/cpp_generator.cc b/grpc/src/compiler/cpp_generator.cc
index 16e3373b..fd635f2f 100644
--- a/grpc/src/compiler/cpp_generator.cc
+++ b/grpc/src/compiler/cpp_generator.cc
@@ -8,23 +8,24 @@
 namespace grpc_cpp_generator {
 namespace {
 
-grpc::string service_header_ext() { return ".grpc.fb.h"; }
+static grpc::string service_header_ext() { return ".grpc.fb.h"; }
 
-template<class T> grpc::string as_string(T x) {
+template<class T>
+static grpc::string as_string(T x) {
   std::ostringstream out;
   out << x;
   return out.str();
 }
 
-inline bool ClientOnlyStreaming(const grpc_generator::Method *method) {
+static inline bool ClientOnlyStreaming(const grpc_generator::Method *method) {
   return method->ClientStreaming() && !method->ServerStreaming();
 }
 
-inline bool ServerOnlyStreaming(const grpc_generator::Method *method) {
+static inline bool ServerOnlyStreaming(const grpc_generator::Method *method) {
   return !method->ClientStreaming() && method->ServerStreaming();
 }
 
-grpc::string FilenameIdentifier(const grpc::string &filename) {
+static grpc::string FilenameIdentifier(const grpc::string &filename) {
   grpc::string result;
   for (unsigned i = 0; i < filename.size(); i++) {
     char c = filename[i];
@@ -39,11 +40,11 @@ grpc::string FilenameIdentifier(const grpc::string &filename) {
   }
   return result;
 }
-}  // namespace
 
-template<class T, size_t N> T *array_end(T (&array)[N]) { return array + N; }
+template<class T, size_t N>
+static T *array_end(T (&array)[N]) { return array + N; }
 
-void PrintIncludes(grpc_generator::Printer *printer,
+static void PrintIncludes(grpc_generator::Printer *printer,
                    const std::vector<grpc::string> &headers,
                    const Parameters &params) {
   std::map<grpc::string, grpc::string> vars;
@@ -63,6 +64,8 @@ void PrintIncludes(grpc_generator::Printer *printer,
   }
 }
 
+}  // namespace
+
 grpc::string GetHeaderPrologue(grpc_generator::File *file,
                                const Parameters &params) {
   grpc::string output;
@@ -137,7 +140,10 @@ grpc::string GetHeaderIncludes(grpc_generator::File *file,
   return output;
 }
 
-void PrintHeaderClientMethodInterfaces(
+
+namespace {
+
+static void PrintHeaderClientMethodInterfaces(
     grpc_generator::Printer *printer, const grpc_generator::Method *method,
     std::map<grpc::string, grpc::string> *vars, bool is_public) {
   (*vars)["Method"] = method->name();
@@ -351,7 +357,9 @@ void PrintHeaderClientMethodInterfaces(
   }
 }
 
-void PrintHeaderClientMethod(grpc_generator::Printer *printer,
+
+
+static void PrintHeaderClientMethod(grpc_generator::Printer *printer,
                              const grpc_generator::Method *method,
                              std::map<grpc::string, grpc::string> *vars,
                              bool is_public) {
@@ -554,7 +562,7 @@ void PrintHeaderClientMethod(grpc_generator::Printer *printer,
   }
 }
 
-void PrintHeaderClientMethodData(grpc_generator::Printer *printer,
+static void PrintHeaderClientMethodData(grpc_generator::Printer *printer,
                                  const grpc_generator::Method *method,
                                  std::map<grpc::string, grpc::string> *vars) {
   (*vars)["Method"] = method->name();
@@ -562,7 +570,7 @@ void PrintHeaderClientMethodData(grpc_generator::Printer *printer,
                  "const ::grpc::internal::RpcMethod rpcmethod_$Method$_;\n");
 }
 
-void PrintHeaderServerMethodSync(grpc_generator::Printer *printer,
+static void PrintHeaderServerMethodSync(grpc_generator::Printer *printer,
                                  const grpc_generator::Method *method,
                                  std::map<grpc::string, grpc::string> *vars) {
   (*vars)["Method"] = method->name();
@@ -596,7 +604,7 @@ void PrintHeaderServerMethodSync(grpc_generator::Printer *printer,
   printer->Print(method->GetTrailingComments("//").c_str());
 }
 
-void PrintHeaderServerMethodAsync(grpc_generator::Printer *printer,
+static void PrintHeaderServerMethodAsync(grpc_generator::Printer *printer,
                                   const grpc_generator::Method *method,
                                   std::map<grpc::string, grpc::string> *vars) {
   (*vars)["Method"] = method->name();
@@ -712,7 +720,7 @@ void PrintHeaderServerMethodAsync(grpc_generator::Printer *printer,
   printer->Print(*vars, "};\n");
 }
 
-void PrintHeaderServerMethodStreamedUnary(
+static void PrintHeaderServerMethodStreamedUnary(
     grpc_generator::Printer *printer, const grpc_generator::Method *method,
     std::map<grpc::string, grpc::string> *vars) {
   (*vars)["Method"] = method->name();
@@ -763,7 +771,7 @@ void PrintHeaderServerMethodStreamedUnary(
   }
 }
 
-void PrintHeaderServerMethodSplitStreaming(
+static void PrintHeaderServerMethodSplitStreaming(
     grpc_generator::Printer *printer, const grpc_generator::Method *method,
     std::map<grpc::string, grpc::string> *vars) {
   (*vars)["Method"] = method->name();
@@ -816,7 +824,7 @@ void PrintHeaderServerMethodSplitStreaming(
   }
 }
 
-void PrintHeaderServerMethodGeneric(
+static void PrintHeaderServerMethodGeneric(
     grpc_generator::Printer *printer, const grpc_generator::Method *method,
     std::map<grpc::string, grpc::string> *vars) {
   (*vars)["Method"] = method->name();
@@ -887,7 +895,7 @@ void PrintHeaderServerMethodGeneric(
   printer->Print(*vars, "};\n");
 }
 
-void PrintHeaderService(grpc_generator::Printer *printer,
+static void PrintHeaderService(grpc_generator::Printer *printer,
                         const grpc_generator::Service *service,
                         std::map<grpc::string, grpc::string> *vars) {
   (*vars)["Service"] = service->name();
@@ -1058,6 +1066,8 @@ void PrintHeaderService(grpc_generator::Printer *printer,
   printer->Print(service->GetTrailingComments("//").c_str());
 }
 
+} // namespace
+
 grpc::string GetHeaderServices(grpc_generator::File *file,
                                const Parameters &params) {
   grpc::string output;
@@ -1176,7 +1186,10 @@ grpc::string GetSourceIncludes(grpc_generator::File *file,
   return output;
 }
 
-void PrintSourceClientMethod(grpc_generator::Printer *printer,
+
+namespace {
+
+static void PrintSourceClientMethod(grpc_generator::Printer *printer,
                              const grpc_generator::Method *method,
                              std::map<grpc::string, grpc::string> *vars) {
   (*vars)["Method"] = method->name();
@@ -1320,7 +1333,7 @@ void PrintSourceClientMethod(grpc_generator::Printer *printer,
   }
 }
 
-void PrintSourceServerMethod(grpc_generator::Printer *printer,
+static void PrintSourceServerMethod(grpc_generator::Printer *printer,
                              const grpc_generator::Method *method,
                              std::map<grpc::string, grpc::string> *vars) {
   (*vars)["Method"] = method->name();
@@ -1369,7 +1382,7 @@ void PrintSourceServerMethod(grpc_generator::Printer *printer,
   }
 }
 
-void PrintSourceService(grpc_generator::Printer *printer,
+static void PrintSourceService(grpc_generator::Printer *printer,
                         const grpc_generator::Service *service,
                         std::map<grpc::string, grpc::string> *vars) {
   (*vars)["Service"] = service->name();
@@ -1486,6 +1499,8 @@ void PrintSourceService(grpc_generator::Printer *printer,
   }
 }
 
+} // namespace
+
 grpc::string GetSourceServices(grpc_generator::File *file,
                                const Parameters &params) {
   grpc::string output;
@@ -1588,7 +1603,10 @@ grpc::string GetMockIncludes(grpc_generator::File *file,
   return output;
 }
 
-void PrintMockClientMethods(grpc_generator::Printer *printer,
+
+namespace {
+
+static void PrintMockClientMethods(grpc_generator::Printer *printer,
                             const grpc_generator::Method *method,
                             std::map<grpc::string, grpc::string> *vars) {
   (*vars)["Method"] = method->name();
@@ -1680,7 +1698,7 @@ void PrintMockClientMethods(grpc_generator::Printer *printer,
   }
 }
 
-void PrintMockService(grpc_generator::Printer *printer,
+static void PrintMockService(grpc_generator::Printer *printer,
                       const grpc_generator::Service *service,
                       std::map<grpc::string, grpc::string> *vars) {
   (*vars)["Service"] = service->name();
@@ -1696,6 +1714,8 @@ void PrintMockService(grpc_generator::Printer *printer,
   printer->Print("};\n");
 }
 
+} // namespace
+
 grpc::string GetMockServices(grpc_generator::File *file,
                              const Parameters &params) {
   grpc::string output;
diff --git a/grpc/src/compiler/go_generator.cc b/grpc/src/compiler/go_generator.cc
index 9ba2e65f..ad4694b1 100644
--- a/grpc/src/compiler/go_generator.cc
+++ b/grpc/src/compiler/go_generator.cc
@@ -19,22 +19,23 @@ inline bool ServerOnlyStreaming(const grpc_generator::Method *method) {
 }
 
 namespace grpc_go_generator {
+namespace {
 
 // Returns string with first letter to lowerCase
-grpc::string unexportName(grpc::string s) {
+static grpc::string unexportName(grpc::string s) {
   if (s.empty()) return s;
   s[0] = static_cast<char>(std::tolower(s[0]));
   return s;
 }
 
 // Returns string with first letter to uppercase
-grpc::string exportName(grpc::string s) {
+static grpc::string exportName(grpc::string s) {
   if (s.empty()) return s;
   s[0] = static_cast<char>(std::toupper(s[0]));
   return s;
 }
 
-void GenerateError(grpc_generator::Printer *printer,
+static void GenerateError(grpc_generator::Printer *printer,
                    std::map<grpc::string, grpc::string> vars,
                    const bool multiple_return = true) {
   printer->Print(vars, "if $Error_Check$ {\n");
@@ -46,7 +47,7 @@ void GenerateError(grpc_generator::Printer *printer,
 }
 
 // Generates imports for the service
-void GenerateImports(grpc_generator::File *file,
+static void GenerateImports(grpc_generator::File *file,
                      grpc_generator::Printer *printer,
                      std::map<grpc::string, grpc::string> vars) {
   vars["filename"] = file->filename();
@@ -66,7 +67,7 @@ void GenerateImports(grpc_generator::File *file,
 }
 
 // Generates Server method signature source
-void GenerateServerMethodSignature(const grpc_generator::Method *method,
+static void GenerateServerMethodSignature(const grpc_generator::Method *method,
                                    grpc_generator::Printer *printer,
                                    std::map<grpc::string, grpc::string> vars) {
   vars["Method"] = exportName(method->name());
@@ -86,7 +87,7 @@ void GenerateServerMethodSignature(const grpc_generator::Method *method,
   }
 }
 
-void GenerateServerMethod(const grpc_generator::Method *method,
+static void GenerateServerMethod(const grpc_generator::Method *method,
                           grpc_generator::Printer *printer,
                           std::map<grpc::string, grpc::string> vars) {
   vars["Method"] = exportName(method->name());
@@ -204,7 +205,7 @@ void GenerateServerMethod(const grpc_generator::Method *method,
 }
 
 // Generates Client method signature source
-void GenerateClientMethodSignature(const grpc_generator::Method *method,
+static void GenerateClientMethodSignature(const grpc_generator::Method *method,
                                    grpc_generator::Printer *printer,
                                    std::map<grpc::string, grpc::string> vars) {
   vars["Method"] = exportName(method->name());
@@ -225,7 +226,7 @@ void GenerateClientMethodSignature(const grpc_generator::Method *method,
 }
 
 // Generates Client method source
-void GenerateClientMethod(const grpc_generator::Method *method,
+static void GenerateClientMethod(const grpc_generator::Method *method,
                           grpc_generator::Printer *printer,
                           std::map<grpc::string, grpc::string> vars) {
   printer->Print(vars, "func (c *$ServiceUnexported$Client) ");
@@ -480,6 +481,7 @@ void GenerateService(const grpc_generator::Service *service,
   printer->Outdent();
   printer->Print("}\n");
 }
+}  // namespace
 
 // Returns source for the service
 grpc::string GenerateServiceSource(grpc_generator::File *file,
diff --git a/grpc/src/compiler/java_generator.cc b/grpc/src/compiler/java_generator.cc
index 98f8788d..bfe2b111 100644
--- a/grpc/src/compiler/java_generator.cc
+++ b/grpc/src/compiler/java_generator.cc
@@ -44,8 +44,9 @@ typedef grpc_generator::Method MethodDescriptor;
 
 namespace grpc_java_generator {
 typedef std::string string;
+namespace {
 // Generates imports for the service
-void GenerateImports(grpc_generator::File *file,
+static void GenerateImports(grpc_generator::File *file,
                      grpc_generator::Printer *printer, VARS &vars) {
   vars["filename"] = file->filename();
   printer->Print(vars,
@@ -287,7 +288,7 @@ static void GrpcWriteServiceDocComment(Printer *printer, VARS &vars,
   printer->Print(" */\n");
 }
 
-void GrpcWriteMethodDocComment(Printer *printer, VARS &vars,
+static void GrpcWriteMethodDocComment(Printer *printer, VARS &vars,
                                const MethodDescriptor *method) {
   printer->Print("/**\n");
   std::vector<string> lines = GrpcGetDocLinesForDescriptor(method);
@@ -1029,7 +1030,7 @@ static void PrintService(Printer *p, VARS &vars,
   p->Print("}\n");
 }
 
-void PrintStaticImports(Printer *p) {
+static void PrintStaticImports(Printer *p) {
   p->Print(
       "import java.nio.ByteBuffer;\n"
       "import static "
@@ -1062,7 +1063,7 @@ void PrintStaticImports(Printer *p) {
       "io.grpc.stub.ServerCalls.asyncUnimplementedUnaryCall;\n\n");
 }
 
-void GenerateService(const grpc_generator::Service *service,
+static void GenerateService(const grpc_generator::Service *service,
                      grpc_generator::Printer *printer, VARS &vars,
                      bool disable_version) {
   // All non-generated classes must be referred by fully qualified names to
@@ -1097,6 +1098,7 @@ void GenerateService(const grpc_generator::Service *service,
 
   PrintService(printer, vars, service, disable_version);
 }
+} // namespace
 
 grpc::string GenerateServiceSource(
     grpc_generator::File *file, const grpc_generator::Service *service,
diff --git a/grpc/src/compiler/python_generator.cc b/grpc/src/compiler/python_generator.cc
index 8108db45..d5f69e20 100644
--- a/grpc/src/compiler/python_generator.cc
+++ b/grpc/src/compiler/python_generator.cc
@@ -23,8 +23,9 @@
 #include "src/compiler/python_generator.h"
 
 namespace grpc_python_generator {
+namespace {
 
-grpc::string GenerateMethodType(const grpc_generator::Method *method) {
+static grpc::string GenerateMethodType(const grpc_generator::Method *method) {
 
   if (method->NoStreaming())
     return "unary_unary";
@@ -131,6 +132,7 @@ void GenerateRegister(const grpc_generator::Service *service,
   printer->Outdent();
   printer->Print("\n");
 }
+} // namespace
 
 grpc::string Generate(grpc_generator::File *file,
                       const grpc_generator::Service *service) {
diff --git a/grpc/src/compiler/swift_generator.cc b/grpc/src/compiler/swift_generator.cc
index 403a803e..b0a96d86 100644
--- a/grpc/src/compiler/swift_generator.cc
+++ b/grpc/src/compiler/swift_generator.cc
@@ -28,8 +28,9 @@
 #include "src/compiler/swift_generator.h"
 
 namespace grpc_swift_generator {
+namespace {
 
-std::string WrapInNameSpace(const std::vector<std::string> &components,
+static std::string WrapInNameSpace(const std::vector<std::string> &components,
                             const grpc::string &name) {
   std::string qualified_name;
   for (auto it = components.begin(); it != components.end(); ++it)
@@ -37,14 +38,14 @@ std::string WrapInNameSpace(const std::vector<std::string> &components,
   return qualified_name + name;
 }
 
-grpc::string GenerateMessage(const std::vector<std::string> &components,
+static grpc::string GenerateMessage(const std::vector<std::string> &components,
                              const grpc::string &name) {
   return "Message<" + WrapInNameSpace(components, name) + ">";
 }
 
 // MARK: - Client
 
-void GenerateClientFuncName(const grpc_generator::Method *method,
+static void GenerateClientFuncName(const grpc_generator::Method *method,
                             grpc_generator::Printer *printer,
                             std::map<grpc::string, grpc::string> *dictonary) {
   auto vars = *dictonary;
@@ -82,7 +83,7 @@ void GenerateClientFuncName(const grpc_generator::Method *method,
                  "  ) -> BidirectionalStreamingCall<$Input$, $Output$>");
 }
 
-void GenerateClientFuncBody(const grpc_generator::Method *method,
+static void GenerateClientFuncBody(const grpc_generator::Method *method,
                             grpc_generator::Printer *printer,
                             std::map<grpc::string, grpc::string> *dictonary) {
   auto vars = *dictonary;
@@ -372,6 +373,7 @@ void GenerateServerProtocol(const grpc_generator::Service *service,
   }
   printer->Print("}");
 }
+} // namespace
 
 grpc::string Generate(grpc_generator::File *file,
                       const grpc_generator::Service *service) {
diff --git a/grpc/src/compiler/ts_generator.cc b/grpc/src/compiler/ts_generator.cc
index 3c3daf0d..ff362b77 100644
--- a/grpc/src/compiler/ts_generator.cc
+++ b/grpc/src/compiler/ts_generator.cc
@@ -30,8 +30,9 @@
 #include "src/compiler/schema_interface.h"
 
 namespace grpc_ts_generator {
+namespace {
 
-grpc::string GenerateNamespace(const std::vector<std::string> ns,
+static grpc::string GenerateNamespace(const std::vector<std::string> ns,
                                const std::string filename,
                                const bool include_separator) {
   grpc::string path = "";
@@ -55,7 +56,7 @@ grpc::string GenerateNamespace(const std::vector<std::string> ns,
 
 // MARK: - Shared code
 
-void GenerateImports(const grpc_generator::Service *service,
+static void GenerateImports(const grpc_generator::Service *service,
                      grpc_generator::Printer *printer,
                      std::map<grpc::string, grpc::string> *dictonary,
                      const bool grpc_var_import) {
@@ -104,7 +105,7 @@ void GenerateImports(const grpc_generator::Service *service,
 
 // MARK: - Generate Main GRPC Code
 
-void GetStreamType(grpc_generator::Printer *printer,
+static void GetStreamType(grpc_generator::Printer *printer,
                    const grpc_generator::Method *method,
                    std::map<grpc::string, grpc::string> *dictonary) {
   auto vars = *dictonary;
@@ -116,7 +117,7 @@ void GetStreamType(grpc_generator::Printer *printer,
   printer->Print(vars, "responseStream: $ServerStreaming$,\n");
 }
 
-void GenerateSerializeMethod(grpc_generator::Printer *printer,
+static void GenerateSerializeMethod(grpc_generator::Printer *printer,
                              std::map<grpc::string, grpc::string> *dictonary) {
   auto vars = *dictonary;
   printer->Print(vars, "function serialize_$Type$(buffer_args) {\n");
@@ -132,7 +133,7 @@ void GenerateSerializeMethod(grpc_generator::Printer *printer,
   printer->Print("}\n\n");
 }
 
-void GenerateDeserializeMethod(
+static void GenerateDeserializeMethod(
     grpc_generator::Printer *printer,
     std::map<grpc::string, grpc::string> *dictonary) {
   auto vars = *dictonary;
@@ -145,7 +146,7 @@ void GenerateDeserializeMethod(
   printer->Print("}\n\n");
 }
 
-void GenerateMethods(const grpc_generator::Service *service,
+static void GenerateMethods(const grpc_generator::Service *service,
                      grpc_generator::Printer *printer,
                      std::map<grpc::string, grpc::string> *dictonary) {
   auto vars = *dictonary;
@@ -177,7 +178,7 @@ void GenerateMethods(const grpc_generator::Service *service,
   }
 }
 
-void GenerateService(const grpc_generator::Service *service,
+static void GenerateService(const grpc_generator::Service *service,
                      grpc_generator::Printer *printer,
                      std::map<grpc::string, grpc::string> *dictonary) {
   auto vars = *dictonary;
@@ -212,6 +213,8 @@ void GenerateService(const grpc_generator::Service *service,
                  "grpc.makeGenericClientConstructor($NAME$);");
 }
 
+} // namespace
+
 grpc::string Generate(grpc_generator::File *file,
                       const grpc_generator::Service *service,
                       const grpc::string &filename) {
@@ -233,9 +236,11 @@ grpc::string Generate(grpc_generator::File *file,
   return output;
 }
 
+namespace {
+
 // MARK: - Generate Interface
 
-void FillInterface(grpc_generator::Printer *printer,
+static void FillInterface(grpc_generator::Printer *printer,
                    std::map<grpc::string, grpc::string> *dictonary) {
   auto vars = *dictonary;
   printer->Print(vars,
@@ -253,7 +258,7 @@ void FillInterface(grpc_generator::Printer *printer,
   printer->Print("}\n");
 }
 
-void GenerateInterfaces(const grpc_generator::Service *service,
+static void GenerateInterfaces(const grpc_generator::Service *service,
                         grpc_generator::Printer *printer,
                         std::map<grpc::string, grpc::string> *dictonary) {
   auto vars = *dictonary;
@@ -275,7 +280,7 @@ void GenerateInterfaces(const grpc_generator::Service *service,
   }
 }
 
-void GenerateExportedInterface(
+static void GenerateExportedInterface(
     const grpc_generator::Service *service, grpc_generator::Printer *printer,
     std::map<grpc::string, grpc::string> *dictonary) {
   auto vars = *dictonary;
@@ -319,7 +324,7 @@ void GenerateExportedInterface(
   printer->Print("}\n");
 }
 
-void GenerateMainInterface(const grpc_generator::Service *service,
+static void GenerateMainInterface(const grpc_generator::Service *service,
                            grpc_generator::Printer *printer,
                            std::map<grpc::string, grpc::string> *dictonary) {
   auto vars = *dictonary;
@@ -344,11 +349,11 @@ void GenerateMainInterface(const grpc_generator::Service *service,
   GenerateExportedInterface(service, printer, &vars);
 }
 
-grpc::string GenerateMetaData() { return "metadata: grpc.Metadata"; }
+static grpc::string GenerateMetaData() { return "metadata: grpc.Metadata"; }
 
-grpc::string GenerateOptions() { return "options: Partial<grpc.CallOptions>"; }
+static grpc::string GenerateOptions() { return "options: Partial<grpc.CallOptions>"; }
 
-void GenerateUnaryClientInterface(
+static void GenerateUnaryClientInterface(
     grpc_generator::Printer *printer,
     std::map<grpc::string, grpc::string> *dictonary) {
   auto vars = *dictonary;
@@ -363,7 +368,7 @@ void GenerateUnaryClientInterface(
   printer->Print(vars, (main + meta_data + options + callback).c_str());
 }
 
-void GenerateClientWriteStreamInterface(
+static void GenerateClientWriteStreamInterface(
     grpc_generator::Printer *printer,
     std::map<grpc::string, grpc::string> *dictonary) {
   auto vars = *dictonary;
@@ -380,7 +385,7 @@ void GenerateClientWriteStreamInterface(
   printer->Print(vars, (main + meta_data + options + callback).c_str());
 }
 
-void GenerateClientReadableStreamInterface(
+static void GenerateClientReadableStreamInterface(
     grpc_generator::Printer *printer,
     std::map<grpc::string, grpc::string> *dictonary) {
   auto vars = *dictonary;
@@ -392,7 +397,7 @@ void GenerateClientReadableStreamInterface(
   printer->Print(vars, (main + options + end_function).c_str());
 }
 
-void GenerateDepluxStreamInterface(
+static void GenerateDepluxStreamInterface(
     grpc_generator::Printer *printer,
     std::map<grpc::string, grpc::string> *dictonary) {
   auto vars = *dictonary;
@@ -408,7 +413,7 @@ void GenerateDepluxStreamInterface(
                            .c_str());
 }
 
-void GenerateClientInterface(const grpc_generator::Service *service,
+static void GenerateClientInterface(const grpc_generator::Service *service,
                              grpc_generator::Printer *printer,
                              std::map<grpc::string, grpc::string> *dictonary) {
   auto vars = *dictonary;
@@ -446,7 +451,7 @@ void GenerateClientInterface(const grpc_generator::Service *service,
   printer->Print("}\n");
 }
 
-void GenerateClientClassInterface(
+static void GenerateClientClassInterface(
     const grpc_generator::Service *service, grpc_generator::Printer *printer,
     std::map<grpc::string, grpc::string> *dictonary) {
   auto vars = *dictonary;
@@ -487,6 +492,8 @@ void GenerateClientClassInterface(
   printer->Outdent();
   printer->Print("}\n");
 }
+} // namespace
+
 
 grpc::string GenerateInterface(grpc_generator::File *file,
                                const grpc_generator::Service *service,