move some functionality from UseMethodDispatchCachedNode to ArgumentsSignature

com.oracle.truffle.r.nodes/src/com/oracle/truffle/r/nodes/function/UseMethodDispatchNode.java

@@ -199,6 +199,7 @@ final class UseMethodDispatchCachedNode extends S3DispatchCachedNode {
         int argCount = arguments.length;
         int argListSize = argCount;
 
+        // extract vararg signatures from the arguments
         ArgumentsSignature[] varArgSignatures = null;
         for (int i = 0; i < arguments.length; i++) {
             Object arg = arguments[i];
@@ -210,27 +211,12 @@ final class UseMethodDispatchCachedNode extends S3DispatchCachedNode {
                 argListSize += ((RArgsValuesAndNames) arg).length() - 1;
             }
         }
+
         long[] preparePermutation;
         ArgumentsSignature resultSignature;
         if (varArgSignatures != null) {
-            preparePermutation = new long[argListSize];
-            String[] argNames = new String[argListSize];
-            int index = 0;
-            for (int fi = 0; fi < argCount; ++fi) {
-                Object arg = arguments[fi];
-                if (arg instanceof RArgsValuesAndNames) {
-                    RArgsValuesAndNames varArgs = (RArgsValuesAndNames) arg;
-                    ArgumentsSignature varArgSignature = varArgs.getSignature();
-                    for (int i = 0; i < varArgs.length(); i++) {
-                        argNames[index] = varArgSignature.getName(i);
-                        preparePermutation[index++] = -((((long) fi) << 32) + i);
-                    }
-                } else {
-                    argNames[index] = signature.getName(fi);
-                    preparePermutation[index++] = fi;
-                }
-            }
-            resultSignature = ArgumentsSignature.get(argNames);
+            resultSignature = ArgumentsSignature.flattenNames(signature, varArgSignatures, argListSize);
+            preparePermutation = ArgumentsSignature.flattenIndexes(varArgSignatures, argListSize);
         } else {
             preparePermutation = new long[argCount];
             for (int i = 0; i < argCount; i++) {
@@ -239,7 +225,7 @@ final class UseMethodDispatchCachedNode extends S3DispatchCachedNode {
             resultSignature = signature;
         }
 
-        assert signature != null;
+        assert resultSignature != null;
         MatchPermutation permutation = ArgumentMatcher.matchArguments(result.targetFunction, resultSignature, getEncapsulatingSourceSection(), false);
 
         CheckReadsNode newCheckedReads = new CheckReadsNode(unsuccessfulReadsCaller, unsuccessfulReadsDef, result.successfulRead, result.targetFunction, result.clazz, result.targetFunctionName,

com.oracle.truffle.r.runtime/src/com/oracle/truffle/r/runtime/ArgumentsSignature.java

@@ -165,4 +165,40 @@ public final class ArgumentsSignature implements Iterable<String> {
     public String toString() {
         return "Signature " + Arrays.toString(names);
     }
+
+    /*
+     * Utility functions
+     */
+
+    public static long[] flattenIndexes(ArgumentsSignature[] varArgSignatures, int argListSize) {
+        long[] preparePermutation = new long[argListSize];
+        int index = 0;
+        for (int i = 0; i < varArgSignatures.length; i++) {
+            ArgumentsSignature varArgSignature = varArgSignatures[i];
+            if (varArgSignature != null) {
+                for (int j = 0; j < varArgSignature.getLength(); j++) {
+                    preparePermutation[index++] = -((((long) i) << 32) + j);
+                }
+            } else {
+                preparePermutation[index++] = i;
+            }
+        }
+        return preparePermutation;
+    }
+
+    public static ArgumentsSignature flattenNames(ArgumentsSignature signature, ArgumentsSignature[] varArgSignatures, int argListSize) {
+        String[] argNames = new String[argListSize];
+        int index = 0;
+        for (int i = 0; i < varArgSignatures.length; i++) {
+            ArgumentsSignature varArgSignature = varArgSignatures[i];
+            if (varArgSignature != null) {
+                for (int j = 0; j < varArgSignature.getLength(); j++) {
+                    argNames[index++] = varArgSignature.getName(j);
+                }
+            } else {
+                argNames[index++] = signature.getName(i);
+            }
+        }
+        return ArgumentsSignature.get(argNames);
+    }
 }