bug fix; a return may have no instr

git-svn-id: https://svn.code.sf.net/p/jode/code/trunk@328 379699f6-c40d-0410-875b-85095c16579e

jode/jode/flow/ReturnBlock.java

@@ -45,13 +45,14 @@ public class ReturnBlock extends InstructionContainer {
      * @return stack the stack afterwards.
      */
     public VariableStack mapStackToLocal(VariableStack stack) {
-	VariableStack newStack;
+	VariableStack newStack = stack;
+	if (instr != null) {
 	    int params = instr.getOperandCount();
 	    if (params > 0) {
 		this.stack = stack.peek(params);
 		newStack = stack.pop(params);
-	} else 
+	    }
-	    newStack = stack;
+	}
 	return null;
     }