some opt

midend/optimize/DeleteDead.java

@@ -0,0 +1,20 @@
+package midend.optimize;
+
+import java.util.HashSet;
+
+import midend.llvm.value.IrFuncValue;
+
+public class DeleteDead extends Optimizer {
+    public void optimize() {
+
+    }
+
+    public void deleteDeadFunc() {
+        IrFuncValue mainFunc = getIrModule().getMainFunc();
+        HashSet<IrFuncValue> liveFuncs = new HashSet<>();
+        liveFuncs.add(mainFunc);
+        findLiveFuncs(mainFunc, liveFuncs);
+    }
+
+    public void findLiveFuncs()
+}