R_NaString is a CHARSXP

com.oracle.truffle.r.native/fficall/src/jni/Rinternals.c

@@ -389,6 +389,7 @@ SEXP Rf_install(const char *name) {
 }
 
 SEXP Rf_installChar(SEXP charsxp) {
+	TRACE("%s(%p)\n", charsxp);
 	JNIEnv *thisenv = getEnv();
 	jstring string = stringFromCharSXP(thisenv, charsxp);
 	SEXP result = (*thisenv)->CallStaticObjectMethod(thisenv, RDataFactoryClass, createSymbolMethodID, string);

com.oracle.truffle.r.runtime.ffi/src/com/oracle/truffle/r/runtime/ffi/RFFIVariables.java

@@ -29,6 +29,7 @@ import com.oracle.truffle.r.runtime.data.RMissing;
 import com.oracle.truffle.r.runtime.data.RNull;
 import com.oracle.truffle.r.runtime.data.RUnboundValue;
 import com.oracle.truffle.r.runtime.env.REnvironment;
+import com.oracle.truffle.r.runtime.ffi.jnr.CallRFFIHelper;
 
 public enum RFFIVariables {
     R_Home(REnvVars.rHome()),
@@ -70,7 +71,7 @@ public enum RFFIVariables {
     R_dot_target(RDataFactory.createSymbol(".target")),
     R_SrcrefSymbol(RDataFactory.createSymbol("srcref")),
     R_SrcfileSymbol(RDataFactory.createSymbol("srcfile")),
-    R_NaString(RDataFactory.createStringVectorFromScalar(RRuntime.STRING_NA)),
+    R_NaString(CallRFFIHelper.createCharSXP(RRuntime.STRING_NA)),
     R_NaN(Double.NaN),
     R_PosInf(Double.POSITIVE_INFINITY),
     R_NegInf(Double.NEGATIVE_INFINITY),

com.oracle.truffle.r.runtime.ffi/src/com/oracle/truffle/r/runtime/ffi/jnr/CallRFFIHelper.java

@@ -92,6 +92,10 @@ public class CallRFFIHelper {
         }
     }
 
+    public static Object createCharSXP(String contents) {
+        return new CharSXPWrapper(contents);
+    }
+
     private static RuntimeException unimplemented() {
         return unimplemented("");
     }