// File RTCG7.java --- measure time to generate (much) code
// sestoft@dina.kvl.dk * 2002-09

// Using the gnu.bytecode package from http://www.gnu.org/software/kawa

import gnu.bytecode.*;
import java.io.*;

public class RTCG7 {
  public static void main(String[] args) 
    throws IOException, NoSuchMethodException, IllegalAccessException, 
           java.lang.reflect.InvocationTargetException {
    int count = Integer.parseInt(args[0]);
    int calls = Integer.parseInt(args[1]);
    ClassType co = new ClassType("MyClass");
    co.setSuper("java.lang.Object");
    co.setModifiers(Access.PUBLIC);
    Timer t = new Timer();
    {
      // Build: public static void MyMethod1(int x) { ... }
      Method mo = co.addMethod("MyMethod1");
      mo.setSignature("(I)V");
      mo.setModifiers(Access.PUBLIC | Access.STATIC);
      mo.initCode();
      // Obtain a JVM code generator jvmg
      CodeAttr jvmg = mo.getCode();
      Scope scope = mo.pushScope();
      Variable lvar0 = scope.addVariable(jvmg, Type.int_type, "x");
      Label start = new Label(jvmg);
      start.define(jvmg);
      jvmg.emitLoad(lvar0);
      jvmg.emitPushInt(1);
      jvmg.emitAdd('I'); 
      for (int i=count; i>0; i--) {
	jvmg.emitLoad(lvar0);
	jvmg.emitAdd('I'); 
      }
      mo.popScope();
      jvmg.emitReturn();
    }
    // Output class file to array:
    byte[] classFile = co.writeToArray();
    // Load the class file into the JVM 
    Class ty = new ArrayClassLoader().loadClass("MyClass", classFile);
    {
      java.lang.reflect.Method m = 
	ty.getMethod("MyMethod1", new Class[] { int.class }); 
      for (int i=calls; i>0; i--) {
	m.invoke(null, new Object[] { new Integer(count) });
      }
      System.out.println("Generating " + 2*count + " instructions and making " 
			 + calls + " calls: " + t.Check() + " sec");
    }
  }
}

// This is needed because defineClass is protected in java.lang.ClassLoader:

class ArrayClassLoader extends ClassLoader {
  public Class loadClass(String name, byte[] classFile) {
    return defineClass(name, classFile, 0, classFile.length);
  }
}

// Crude timing utility ----------------------------------------
   
class Timer {
  private long start;

  public Timer() {
    start = System.currentTimeMillis();
  }

  public double Check() {
    return (System.currentTimeMillis()-start)/1000.0;
  }
}