/***** BEGIN LICENSE BLOCK *****
 * Version: CPL 1.0/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Common Public
 * License Version 1.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.eclipse.org/legal/cpl-v10.html
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 * 
 * Copyright (C) 2006 The JRuby Community <www.jruby.org>
 * Copyright (C) 2006 Ola Bini <ola@ologix.com>
 * 
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the CPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the CPL, the GPL or the LGPL.
 ***** END LICENSE BLOCK *****/
package org.jruby.internal.runtime.methods;

import java.io.PrintWriter;
import java.lang.reflect.Modifier;
import java.util.List;
import org.jruby.Ruby;
import org.jruby.RubyInstanceConfig;
import org.jruby.RubyKernel;
import org.jruby.parser.StaticScope;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.jruby.RubyModule;
import org.jruby.RubyString;
import org.jruby.anno.JRubyMethod;
import org.jruby.anno.JavaMethodDescriptor;
import org.jruby.compiler.impl.SkinnyMethodAdapter;
import org.jruby.compiler.impl.StandardASMCompiler;
import org.jruby.exceptions.JumpException;
import org.jruby.exceptions.RaiseException;
import org.jruby.lexer.yacc.ISourcePosition;
import org.jruby.runtime.Arity;
import org.jruby.runtime.Block;
import org.jruby.runtime.CompiledBlockCallback;
import org.jruby.runtime.CompiledBlockCallback19;
import org.jruby.runtime.MethodFactory;
import org.jruby.runtime.RubyEvent;
import org.jruby.runtime.ThreadContext;
import org.jruby.runtime.Visibility;
import org.jruby.runtime.builtin.IRubyObject;
import org.jruby.util.CodegenUtils;
import static org.jruby.util.CodegenUtils.*;
import static java.lang.System.*;
import org.jruby.util.JRubyClassLoader;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.Label;
import org.objectweb.asm.util.CheckClassAdapter;

/**
 * In order to avoid the overhead with reflection-based method handles, this
 * MethodFactory uses ASM to generate tiny invoker classes. This allows for
 * better performance and more specialization per-handle than can be supported
 * via reflection. It also allows optimizing away many conditionals that can
 * be determined once ahead of time.
 * 
 * When running in secured environments, this factory may not function. When
 * this can be detected, MethodFactory will fall back on the reflection-based
 * factory instead.
 * 
 * @see org.jruby.internal.runtime.methods.MethodFactory
 */
public class InvocationMethodFactory extends MethodFactory implements Opcodes {
    private static final boolean DEBUG = false;
    
    /** The pathname of the super class for compiled Ruby method handles. */ 
    private final static String COMPILED_SUPER_CLASS = p(CompiledMethod.class);
    
    /** The outward call signature for compiled Ruby method handles. */
    private final static String COMPILED_CALL_SIG = sig(IRubyObject.class,
            params(ThreadContext.class, IRubyObject.class, RubyModule.class, String.class, IRubyObject[].class));
    
    /** The outward call signature for compiled Ruby method handles. */
    private final static String COMPILED_CALL_SIG_BLOCK = sig(IRubyObject.class,
            params(ThreadContext.class, IRubyObject.class, RubyModule.class, String.class, IRubyObject[].class, Block.class));
    
    /** The outward arity-zero call-with-block signature for compiled Ruby method handles. */
    private final static String COMPILED_CALL_SIG_ZERO_BLOCK = sig(IRubyObject.class,
            params(ThreadContext.class, IRubyObject.class, RubyModule.class, String.class, Block.class));
    
    /** The outward arity-zero call-with-block signature for compiled Ruby method handles. */
    private final static String COMPILED_CALL_SIG_ZERO = sig(IRubyObject.class,
            params(ThreadContext.class, IRubyObject.class, RubyModule.class, String.class));
    
    /** The outward arity-zero call-with-block signature for compiled Ruby method handles. */
    private final static String COMPILED_CALL_SIG_ONE_BLOCK = sig(IRubyObject.class,
            params(ThreadContext.class, IRubyObject.class, RubyModule.class, String.class, IRubyObject.class, Block.class));
    
    /** The outward arity-zero call-with-block signature for compiled Ruby method handles. */
    private final static String COMPILED_CALL_SIG_ONE = sig(IRubyObject.class,
            params(ThreadContext.class, IRubyObject.class, RubyModule.class, String.class, IRubyObject.class));
    
    /** The outward arity-zero call-with-block signature for compiled Ruby method handles. */
    private final static String COMPILED_CALL_SIG_TWO_BLOCK = sig(IRubyObject.class,
            params(ThreadContext.class, IRubyObject.class, RubyModule.class, String.class, IRubyObject.class, IRubyObject.class, Block.class));
    
    /** The outward arity-zero call-with-block signature for compiled Ruby method handles. */
    private final static String COMPILED_CALL_SIG_TWO = sig(IRubyObject.class,
            params(ThreadContext.class, IRubyObject.class, RubyModule.class, String.class, IRubyObject.class, IRubyObject.class));
    
    /** The outward arity-zero call-with-block signature for compiled Ruby method handles. */
    private final static String COMPILED_CALL_SIG_THREE_BLOCK = sig(IRubyObject.class,
            params(ThreadContext.class, IRubyObject.class, RubyModule.class, String.class, IRubyObject.class, IRubyObject.class, IRubyObject.class, Block.class));
    
    /** The outward arity-zero call-with-block signature for compiled Ruby method handles. */
    private final static String COMPILED_CALL_SIG_THREE = sig(IRubyObject.class,
            params(ThreadContext.class, IRubyObject.class, RubyModule.class, String.class, IRubyObject.class, IRubyObject.class, IRubyObject.class));

    private final static String BLOCK_CALL_SIG = sig(RubyKernel.IRUBY_OBJECT, params(
            ThreadContext.class, RubyKernel.IRUBY_OBJECT, IRubyObject.class, Block.class));
    private final static String BLOCK_CALL_SIG19 = sig(RubyKernel.IRUBY_OBJECT, params(
            ThreadContext.class, IRubyObject.class, IRubyObject[].class, Block.class));
    
    /** The super constructor signature for Java-based method handles. */
    private final static String JAVA_SUPER_SIG = sig(Void.TYPE, params(RubyModule.class, Visibility.class));
    
    /** The lvar index of "this" */
    public static final int THIS_INDEX = 0;
    
    /** The lvar index of the passed-in ThreadContext */
    public static final int THREADCONTEXT_INDEX = 1;
    
    /** The lvar index of the method-receiving object */
    public static final int RECEIVER_INDEX = 2;
    
    /** The lvar index of the RubyClass being invoked against */
    public static final int CLASS_INDEX = 3;
    
    /** The lvar index method name being invoked */
    public static final int NAME_INDEX = 4;
    
    /** The lvar index of the method args on the call */
    public static final int ARGS_INDEX = 5;
    
    /** The lvar index of the passed-in Block on the call */
    public static final int BLOCK_INDEX = 6;

    /** The classloader to use for code loading */
    protected final JRubyClassLoader classLoader;
    
    /**
     * Whether this factory has seen undefined methods already. This is used to
     * detect likely method handle collisions when we expect to create a new
     * handle for each call.
     */
    private boolean seenUndefinedClasses = false;

    /**
     * Whether we've informed the user that we've seen undefined methods; this
     * is to avoid a flood of repetitive information.
     */
    private boolean haveWarnedUser = false;
    
    /**
     * Construct a new InvocationMethodFactory using the specified classloader
     * to load code. If the target classloader is not an instance of
     * JRubyClassLoader, it will be wrapped with one.
     * 
     * @param classLoader The classloader to use, or to wrap if it is not a
     * JRubyClassLoader instance.
     */
    public InvocationMethodFactory(ClassLoader classLoader) {
        if (classLoader instanceof JRubyClassLoader) {
            this.classLoader = (JRubyClassLoader)classLoader;
        } else {
           this.classLoader = new JRubyClassLoader(classLoader);
        }
    }

    /**
     * Use code generation to provide a method handle for a compiled Ruby method.
     * 
     * @see org.jruby.internal.runtime.methods.MethodFactory#getCompiledMethod
     */
    public DynamicMethod getCompiledMethodLazily(
            RubyModule implementationClass, String method, Arity arity, 
            Visibility visibility, StaticScope scope, Object scriptObject, CallConfiguration callConfig, ISourcePosition position) {
        return new CompiledMethod.LazyCompiledMethod(implementationClass, method, arity, visibility, scope, scriptObject, callConfig, position,
                new InvocationMethodFactory(classLoader));
    }

    /**
     * Use code generation to provide a method handle for a compiled Ruby method.
     * 
     * @see org.jruby.internal.runtime.methods.MethodFactory#getCompiledMethod
     */
    public DynamicMethod getCompiledMethod(
            RubyModule implementationClass, String method, Arity arity, 
            Visibility visibility, StaticScope scope, Object scriptObject, CallConfiguration callConfig, ISourcePosition position) {
        Class scriptClass = scriptObject.getClass();
        String typePath = p(scriptClass);
        String invokerName = typePath.replaceAll("/", "_") + "Invoker" + method + arity;
        synchronized (classLoader) {
            Class generatedClass = tryClass(invokerName, scriptClass);

            try {
                if (generatedClass == null) {
                    if (RubyInstanceConfig.JIT_LOADING_DEBUG) {
                        System.err.println("no generated handle in classloader for: " + invokerName);
                    }
                    byte[] invokerBytes = getCompiledMethodOffline(method, typePath, invokerName, arity, scope, callConfig, position.getFile(), position.getStartLine());
                    generatedClass = endCallWithBytes(invokerBytes, invokerName);
                } else if (RubyInstanceConfig.JIT_LOADING_DEBUG) {
                    System.err.println("found generated handle in classloader: " + invokerName);
                }

                CompiledMethod compiledMethod = (CompiledMethod)generatedClass.newInstance();
                compiledMethod.init(implementationClass, arity, visibility, scope, scriptObject, callConfig);
                return compiledMethod;
            } catch(Exception e) {
                e.printStackTrace();
                throw implementationClass.getRuntime().newLoadError(e.getMessage());
            }
        }
    }

    /**
     * Use code generation to provide a method handle for a compiled Ruby method.
     *
     * @see org.jruby.internal.runtime.methods.MethodFactory#getCompiledMethod
     */
    public byte[] getCompiledMethodOffline(
            String method, String className, String invokerPath, Arity arity,
            StaticScope scope, CallConfiguration callConfig, String filename, int line) {
        String sup = COMPILED_SUPER_CLASS;
        ClassWriter cw;
        int dotIndex = invokerPath.lastIndexOf('/');
        cw = createCompiledCtor(invokerPath, invokerPath.substring(dotIndex + 1) + "#" + method.substring(method.lastIndexOf('$') + 1), sup);
        SkinnyMethodAdapter mv = null;
        String signature = null;
        boolean specificArity = false;

        // if trace, need to at least populate a backtrace frame
        if (RubyInstanceConfig.FULL_TRACE_ENABLED) {
            switch (callConfig) {
            case FrameNoneScopeDummy:
                callConfig = CallConfiguration.FrameBacktraceScopeDummy;
                break;
            case FrameNoneScopeFull:
                callConfig = CallConfiguration.FrameBacktraceScopeFull;
                break;
            case FrameNoneScopeNone:
                callConfig = CallConfiguration.FrameBacktraceScopeNone;
                break;
            }
        }

        if (scope.getRestArg() >= 0 || scope.getOptionalArgs() > 0 || scope.getRequiredArgs() > 3) {
            signature = COMPILED_CALL_SIG_BLOCK;
            mv = new SkinnyMethodAdapter(cw.visitMethod(ACC_PUBLIC, "call", signature, null, null));
        } else {
            specificArity = true;

            mv = new SkinnyMethodAdapter(cw.visitMethod(ACC_PUBLIC, "call", COMPILED_CALL_SIG_BLOCK, null, null));
            mv.start();
            mv.line(-1);

            // check arity
            mv.aloadMany(0, 1, 4, 5); // method, context, name, args, required
            mv.pushInt(scope.getRequiredArgs());
            mv.invokestatic(p(JavaMethod.class), "checkArgumentCount", sig(void.class, JavaMethod.class, ThreadContext.class, String.class, IRubyObject[].class, int.class));

            mv.aloadMany(0, 1, 2, 3, 4);
            for (int i = 0; i < scope.getRequiredArgs(); i++) {
                mv.aload(5);
                mv.ldc(i);
                mv.arrayload();
            }
            mv.aload(6);

            switch (scope.getRequiredArgs()) {
            case 0:
                signature = COMPILED_CALL_SIG_ZERO_BLOCK;
                break;
            case 1:
                signature = COMPILED_CALL_SIG_ONE_BLOCK;
                break;
            case 2:
                signature = COMPILED_CALL_SIG_TWO_BLOCK;
                break;
            case 3:
                signature = COMPILED_CALL_SIG_THREE_BLOCK;
                break;
            }

            mv.invokevirtual(invokerPath, "call", signature);
            mv.areturn();
            mv.end();

            // Define a second version that doesn't take a block, so we have unique code paths for both cases.
            switch (scope.getRequiredArgs()) {
            case 0:
                signature = COMPILED_CALL_SIG_ZERO;
                break;
            case 1:
                signature = COMPILED_CALL_SIG_ONE;
                break;
            case 2:
                signature = COMPILED_CALL_SIG_TWO;
                break;
            case 3:
                signature = COMPILED_CALL_SIG_THREE;
                break;
            }
            mv = new SkinnyMethodAdapter(cw.visitMethod(ACC_PUBLIC, "call", signature, null, null));
            mv.start();
            mv.line(-1);

            mv.aloadMany(0, 1, 2, 3, 4);
            for (int i = 1; i <= scope.getRequiredArgs(); i++) {
                mv.aload(4 + i);
            }
            mv.getstatic(p(Block.class), "NULL_BLOCK", ci(Block.class));

            switch (scope.getRequiredArgs()) {
            case 0:
                signature = COMPILED_CALL_SIG_ZERO_BLOCK;
                break;
            case 1:
                signature = COMPILED_CALL_SIG_ONE_BLOCK;
                break;
            case 2:
                signature = COMPILED_CALL_SIG_TWO_BLOCK;
                break;
            case 3:
                signature = COMPILED_CALL_SIG_THREE_BLOCK;
                break;
            }

            mv.invokevirtual(invokerPath, "call", signature);
            mv.areturn();
            mv.end();

            mv = new SkinnyMethodAdapter(cw.visitMethod(ACC_PUBLIC, "call", signature, null, null));
        }

        mv.visitCode();
        mv.line(-1);

        // invoke pre method stuff
        if (!callConfig.isNoop() || RubyInstanceConfig.FULL_TRACE_ENABLED) {
            if (specificArity) {
                invokeCallConfigPre(mv, COMPILED_SUPER_CLASS, scope.getRequiredArgs(), true, callConfig);
            } else {
                invokeCallConfigPre(mv, COMPILED_SUPER_CLASS, -1, true, callConfig);
            }
        }

        int traceBoolIndex = -1;
        if (RubyInstanceConfig.FULL_TRACE_ENABLED) {
            // load and store trace enabled flag
            if (specificArity) {
                switch (scope.getRequiredArgs()) {
                case -1:
                    traceBoolIndex = ARGS_INDEX + 1/*block*/ + 1;
                    break;
                case 0:
                    traceBoolIndex = ARGS_INDEX + 1/*block*/;
                    break;
                default:
                    traceBoolIndex = ARGS_INDEX + scope.getRequiredArgs() + 1/*block*/ + 1;
                }
            } else {
                traceBoolIndex = ARGS_INDEX + 1/*block*/ + 1;
            }

            mv.aload(1);
            mv.invokevirtual(p(ThreadContext.class), "getRuntime", sig(Ruby.class));
            mv.invokevirtual(p(Ruby.class), "hasEventHooks", sig(boolean.class));
            mv.istore(traceBoolIndex);
            // tracing pre
            invokeTraceCompiledPre(mv, COMPILED_SUPER_CLASS, traceBoolIndex, filename, line);
        }

        Label tryBegin = new Label();
        Label tryEnd = new Label();
        Label doFinally = new Label();
        Label doReturnFinally = new Label();
        Label doRedoFinally = new Label();
        Label catchReturnJump = new Label();
        Label catchRedoJump = new Label();

        boolean heapScoped = callConfig.scoping() == Scoping.Full;
        boolean framed = callConfig.framing() == Framing.Full;

        if (framed || heapScoped)   mv.trycatch(tryBegin, tryEnd, catchReturnJump, p(JumpException.ReturnJump.class));
        if (framed)                 mv.trycatch(tryBegin, tryEnd, catchRedoJump, p(JumpException.RedoJump.class));
        if (framed || heapScoped)   mv.trycatch(tryBegin, tryEnd, doFinally, null);
        if (framed || heapScoped)   mv.trycatch(catchReturnJump, doReturnFinally, doFinally, null);
        if (framed)                 mv.trycatch(catchRedoJump, doRedoFinally, doFinally, null);
        if (framed || heapScoped)   mv.label(tryBegin);

        // main body
        {
            mv.aload(0);
            // FIXME we want to eliminate these type casts when possible
            mv.getfield(invokerPath, "$scriptObject", ci(Object.class));
            mv.checkcast(className);
            mv.aloadMany(THREADCONTEXT_INDEX, RECEIVER_INDEX);
            if (specificArity) {
                for (int i = 0; i < scope.getRequiredArgs(); i++) {
                    mv.aload(ARGS_INDEX + i);
                }
                mv.aload(ARGS_INDEX + scope.getRequiredArgs());
                mv.invokestatic(className, method, StandardASMCompiler.getStaticMethodSignature(className, scope.getRequiredArgs()));
            } else {
                mv.aloadMany(ARGS_INDEX, BLOCK_INDEX);
                mv.invokestatic(className, method, StandardASMCompiler.getStaticMethodSignature(className, 4));
            }
        }
        if (framed || heapScoped) {
            mv.label(tryEnd);
        }

        // normal exit, perform finally and return
        {
            if (RubyInstanceConfig.FULL_TRACE_ENABLED) {
                invokeTraceCompiledPost(mv, COMPILED_SUPER_CLASS, traceBoolIndex);
            }
            if (!callConfig.isNoop()) {
                invokeCallConfigPost(mv, COMPILED_SUPER_CLASS, callConfig);
            }
            mv.visitInsn(ARETURN);
        }

        // return jump handling
        if (framed || heapScoped) {
            mv.label(catchReturnJump);
            {
                mv.aload(0);
                mv.swap();
                mv.aload(1);
                mv.swap();
                mv.invokevirtual(COMPILED_SUPER_CLASS, "handleReturn", sig(IRubyObject.class, ThreadContext.class, JumpException.ReturnJump.class));
                mv.label(doReturnFinally);

                // finally
                if (RubyInstanceConfig.FULL_TRACE_ENABLED) {
                    invokeTraceCompiledPost(mv, COMPILED_SUPER_CLASS, traceBoolIndex);
                }
                if (!callConfig.isNoop()) {
                    invokeCallConfigPost(mv, COMPILED_SUPER_CLASS, callConfig);
                }

                // return result if we're still good
                mv.areturn();
            }
        }

        if (framed) {
            // redo jump handling
            mv.label(catchRedoJump);
            {
                // clear the redo
                mv.pop();

                // get runtime, create jump error, and throw it
                mv.aload(1);
                mv.invokevirtual(p(ThreadContext.class), "getRuntime", sig(Ruby.class));
                mv.invokevirtual(p(Ruby.class), "newRedoLocalJumpError", sig(RaiseException.class));
                mv.label(doRedoFinally);

                // finally
                if (RubyInstanceConfig.FULL_TRACE_ENABLED) {
                    invokeTraceCompiledPost(mv, COMPILED_SUPER_CLASS, traceBoolIndex);
                }
                if (!callConfig.isNoop()) {
                    invokeCallConfigPost(mv, COMPILED_SUPER_CLASS, callConfig);
                }

                // throw redo error if we're still good
                mv.athrow();
            }
        }

        // finally handling for abnormal exit
        if (framed || heapScoped) {
            mv.label(doFinally);

            //call post method stuff (exception raised)
            if (RubyInstanceConfig.FULL_TRACE_ENABLED) {
                invokeTraceCompiledPost(mv, COMPILED_SUPER_CLASS, traceBoolIndex);
            }
            if (!callConfig.isNoop()) {
                invokeCallConfigPost(mv, COMPILED_SUPER_CLASS, callConfig);
            }

            // rethrow exception
            mv.athrow(); // rethrow it
        }

        return endCallOffline(cw,mv);
    }
    
    private class DescriptorInfo {
        private int min;
        private int max;
        private boolean frame;
        private boolean scope;
        private boolean backtrace;
        private boolean rest;
        private boolean block;
        
        public DescriptorInfo(List<JavaMethodDescriptor> descs) {
            min = Integer.MAX_VALUE;
            max = 0;
            frame = false;
            scope = false;
            backtrace = false;
            rest = false;
            block = false;

            for (JavaMethodDescriptor desc: descs) {
                int specificArity = -1;
                if (desc.hasVarArgs) {
                    if (desc.optional == 0 && !desc.rest) {
                        throw new RuntimeException("IRubyObject[] args but neither of optional or rest specified for method " + desc.declaringClassName + "." + desc.name);
                    }
                    rest = true;
                } else {
                    if (desc.optional == 0 && !desc.rest) {
                        if (desc.required == 0) {
                            // No required specified, check actual number of required args
                            if (desc.actualRequired <= 3) {
                                // actual required is less than 3, so we use specific arity
                                specificArity = desc.actualRequired;
                            } else {
                                // actual required is greater than 3, raise error (we don't support actual required > 3)
                                throw new RuntimeException("Invalid specific-arity number of arguments (" + desc.actualRequired + ") on method " + desc.declaringClassName + "." + desc.name);
                            }
                        } else if (desc.required >= 0 && desc.required <= 3) {
                            if (desc.actualRequired != desc.required) {
                                throw new RuntimeException("Specified required args does not match actual on method " + desc.declaringClassName + "." + desc.name);
                            }
                            specificArity = desc.required;
                        }
                    }

                    if (specificArity < min) {
                        min = specificArity;
                    }

                    if (specificArity > max) {
                        max = specificArity;
                    }
                }

                frame |= desc.anno.frame();
                scope |= desc.anno.scope();
                backtrace |= desc.anno.backtrace();
                block |= desc.hasBlock;
            }
        }
        
        public boolean isBacktrace() {
            return backtrace;
        }

        public boolean isFrame() {
            return frame;
        }

        public int getMax() {
            return max;
        }

        public int getMin() {
            return min;
        }

        public boolean isScope() {
            return scope;
        }
        
        public boolean isRest() {
            return rest;
        }
        
        public boolean isBlock() {
            return block;
        }
    }

    /**
     * Use code generation to provide a method handle based on an annotated Java
     * method.
     * 
     * @see org.jruby.internal.runtime.methods.MethodFactory#getAnnotatedMethod
     */
    public DynamicMethod getAnnotatedMethod(RubyModule implementationClass, List<JavaMethodDescriptor> descs) {
        JavaMethodDescriptor desc1 = descs.get(0);
        String javaMethodName = desc1.name;
        
        if (DEBUG) out.println("Binding multiple: " + desc1.declaringClassName + "." + javaMethodName);
        
        synchronized (classLoader) {
            try {
                Class c = getAnnotatedMethodClass(descs);
                
                DescriptorInfo info = new DescriptorInfo(descs);
                if (DEBUG) out.println(" min: " + info.getMin() + ", max: " + info.getMax());

                JavaMethod ic = (JavaMethod)c.getConstructor(new Class[]{RubyModule.class, Visibility.class}).newInstance(new Object[]{implementationClass, desc1.anno.visibility()});

                ic.setArity(Arity.OPTIONAL);
                ic.setJavaName(javaMethodName);
                ic.setSingleton(desc1.isStatic);
                ic.setCallConfig(CallConfiguration.getCallConfig(info.isFrame(), info.isScope(), info.isBacktrace()));
                return ic;
            } catch(Exception e) {
                e.printStackTrace();
                throw implementationClass.getRuntime().newLoadError(e.getMessage());
            }
        }
    }

    /**
     * Use code generation to provide a method handle based on an annotated Java
     * method. Return the resulting generated or loaded class.
     * 
     * @see org.jruby.internal.runtime.methods.MethodFactory#getAnnotatedMethod
     */
    public Class getAnnotatedMethodClass(List<JavaMethodDescriptor> descs) throws Exception {
        JavaMethodDescriptor desc1 = descs.get(0);

        if (descs.size() == 1) {
            // simple path, no multimethod
            return getAnnotatedMethodClass(desc1);
        }

        if (!Modifier.isPublic(desc1.getDeclaringClass().getModifiers())) {
            System.err.println("warning: binding non-public class" + desc1.declaringClassName + "; reflected handles won't work");
        }
        
        String javaMethodName = desc1.name;
        
        if (DEBUG) out.println("Binding multiple: " + desc1.declaringClassName + "." + javaMethodName);
        
        String generatedClassName = CodegenUtils.getAnnotatedBindingClassName(javaMethodName, desc1.declaringClassName, desc1.isStatic, desc1.actualRequired, desc1.optional, true, desc1.anno.frame());
        if (RubyInstanceConfig.FULL_TRACE_ENABLED) {
            // in debug mode we append _DBG to class name to force it to regenerate (or use pre-generated debug version)
            generatedClassName += "_DBG";
        }
        String generatedClassPath = generatedClassName.replace('.', '/');
        
        synchronized (classLoader) {
            Class c = tryClass(generatedClassName, desc1.getDeclaringClass());

            DescriptorInfo info = new DescriptorInfo(descs);
            if (DEBUG) out.println(" min: " + info.getMin() + ", max: " + info.getMax() + ", hasBlock: " + info.isBlock() + ", rest: " + info.isRest());

            if (c == null) {
                Class superClass = null;
                if (info.getMin() == -1) {
                    // normal all-rest method
                    superClass = JavaMethod.JavaMethodN.class;
                } else {
                    if (info.isRest()) {
                        if (info.isBlock()) {
                            superClass = JavaMethod.BLOCK_REST_METHODS[info.getMin()][info.getMax()];
                        } else {
                            superClass = JavaMethod.REST_METHODS[info.getMin()][info.getMax()];
                        }
                    } else {
                        if (info.isBlock()) {
                            superClass = JavaMethod.BLOCK_METHODS[info.getMin()][info.getMax()];
                        } else {
                            superClass = JavaMethod.METHODS[info.getMin()][info.getMax()];
                        }
                    }
                }
                
                if (superClass == null) throw new RuntimeException("invalid multi combination");
                String superClassString = p(superClass);
                int dotIndex = desc1.declaringClassName.lastIndexOf('.');
                ClassWriter cw = createJavaMethodCtor(generatedClassPath, desc1.declaringClassName.substring(dotIndex + 1) + "#" + desc1.name, superClassString);

                for (JavaMethodDescriptor desc: descs) {
                    int specificArity = -1;
                    if (desc.optional == 0 && !desc.rest) {
                        if (desc.required == 0) {
                            if (desc.actualRequired <= 3) {
                                specificArity = desc.actualRequired;
                            } else {
                                specificArity = -1;
                            }
                        } else if (desc.required >= 0 && desc.required <= 3) {
                            specificArity = desc.required;
                        }
                    }

                    boolean hasBlock = desc.hasBlock;
                    SkinnyMethodAdapter mv = null;

                    mv = beginMethod(cw, "call", specificArity, hasBlock);
                    mv.visitCode();
                    mv.line(-1);

                    createAnnotatedMethodInvocation(desc, mv, superClassString, specificArity, hasBlock);

                    endMethod(mv);
                }

                c = endClass(cw, generatedClassName);
            }

            return c;
        }
    }

    /**
     * Use code generation to provide a method handle based on an annotated Java
     * method.
     * 
     * @see org.jruby.internal.runtime.methods.MethodFactory#getAnnotatedMethod
     */
    public DynamicMethod getAnnotatedMethod(RubyModule implementationClass, JavaMethodDescriptor desc) {
        String javaMethodName = desc.name;
        
        synchronized (classLoader) {
            try {
                Class c = getAnnotatedMethodClass(desc);

                JavaMethod ic = (JavaMethod)c.getConstructor(new Class[]{RubyModule.class, Visibility.class}).newInstance(new Object[]{implementationClass, desc.anno.visibility()});

                ic.setArity(Arity.fromAnnotation(desc.anno, desc.actualRequired));
                ic.setJavaName(javaMethodName);
                ic.setSingleton(desc.isStatic);
                ic.setCallConfig(CallConfiguration.getCallConfigByAnno(desc.anno));
                return ic;
            } catch(Exception e) {
                e.printStackTrace();
                throw implementationClass.getRuntime().newLoadError(e.getMessage());
            }
        }
    }

    /**
     * Use code generation to provide a method handle based on an annotated Java
     * method.
     * 
     * @see org.jruby.internal.runtime.methods.MethodFactory#getAnnotatedMethod
     */
    public Class getAnnotatedMethodClass(JavaMethodDescriptor desc) throws Exception {
        String javaMethodName = desc.name;

        if (!Modifier.isPublic(desc.getDeclaringClass().getModifiers())) {
            System.err.println("warning: binding non-public class " + desc.declaringClassName + "; reflected handles won't work");
        }
        
        String generatedClassName = CodegenUtils.getAnnotatedBindingClassName(javaMethodName, desc.declaringClassName, desc.isStatic, desc.actualRequired, desc.optional, false, desc.anno.frame());
        if (RubyInstanceConfig.FULL_TRACE_ENABLED) {
            // in debug mode we append _DBG to class name to force it to regenerate (or use pre-generated debug version)
            generatedClassName += "_DBG";
        }
        String generatedClassPath = generatedClassName.replace('.', '/');
        
        synchronized (classLoader) {
            Class c = tryClass(generatedClassName, desc.getDeclaringClass());

            if (c == null) {
                int specificArity = -1;
                if (desc.optional == 0 && !desc.rest) {
                    if (desc.required == 0) {
                        if (desc.actualRequired <= 3) {
                            specificArity = desc.actualRequired;
                        } else {
                            specificArity = -1;
                        }
                    } else if (desc.required >= 0 && desc.required <= 3) {
                        specificArity = desc.required;
                    }
                }

                boolean block = desc.hasBlock;

                String superClass = p(selectSuperClass(specificArity, block));

                int dotIndex = desc.declaringClassName.lastIndexOf('.');
                ClassWriter cw = createJavaMethodCtor(generatedClassPath, desc.declaringClassName.substring(dotIndex + 1) + "#" + desc.name, superClass);
                SkinnyMethodAdapter mv = null;

                mv = beginMethod(cw, "call", specificArity, block);
                mv.visitCode();
                mv.line(-1);

                createAnnotatedMethodInvocation(desc, mv, superClass, specificArity, block);

                endMethod(mv);

                c = endClass(cw, generatedClassName);
            }
            
            return c;
        }
    }

    public CompiledBlockCallback getBlockCallback(String method, Object scriptObject) {
        Class typeClass = scriptObject.getClass();
        String typePathString = p(typeClass);
        String mname = typeClass.getName() + "BlockCallback$" + method + "xx1";
        synchronized (classLoader) {
            Class c = tryClass(mname);
            try {
                if (c == null) {
                    if (RubyInstanceConfig.JIT_LOADING_DEBUG) {
                        System.err.println("no generated handle in classloader for: " + mname);
                    }
                    byte[] bytes = getBlockCallbackOffline(method, typePathString);
                    c = endCallWithBytes(bytes, mname);
                } else {
                    if (RubyInstanceConfig.JIT_LOADING_DEBUG) {
                        System.err.println("found generated handle in classloader for: " + mname);
                    }
                }
                
                CompiledBlockCallback ic = (CompiledBlockCallback) c.getConstructor(Object.class).newInstance(scriptObject);
                return ic;
            } catch (IllegalArgumentException e) {
                throw e;
            } catch (Exception e) {
                e.printStackTrace();
                throw new IllegalArgumentException(e.getMessage());
            }
        }
    }

    @Override
    public byte[] getBlockCallbackOffline(String method, String classname) {
        String mnamePath = classname + "BlockCallback$" + method + "xx1";
        ClassWriter cw = createBlockCtor(mnamePath, classname);
        SkinnyMethodAdapter mv = startBlockCall(cw);
        mv.line(-1);
        mv.aload(0);
        mv.getfield(mnamePath, "$scriptObject", "L" + classname + ";");
        mv.aloadMany(1, 2, 3, 4);
        mv.invokestatic(classname, method, sig(
                IRubyObject.class, "L" + classname + ";", ThreadContext.class,
                        IRubyObject.class, IRubyObject.class, Block.class));
        mv.areturn();

        mv.visitMaxs(2, 3);
        return endCallOffline(cw, mv);
    }

    public CompiledBlockCallback19 getBlockCallback19(String method, Object scriptObject) {
        Class typeClass = scriptObject.getClass();
        String typePathString = p(typeClass);
        String mname = typeClass.getName() + "BlockCallback$" + method + "xx1";
        synchronized (classLoader) {
            Class c = tryClass(mname);
            try {
                if (c == null) {
                    if (RubyInstanceConfig.JIT_LOADING_DEBUG) {
                        System.err.println("no generated handle in classloader for: " + mname);
                    }
                    byte[] bytes = getBlockCallback19Offline(method, typePathString);
                    c = endClassWithBytes(bytes, mname);
                } else {
                    if (RubyInstanceConfig.JIT_LOADING_DEBUG) {
                        System.err.println("found generated handle in classloader for: " + mname);
                    }
                }
                
                CompiledBlockCallback19 ic = (CompiledBlockCallback19) c.getConstructor(Object.class).newInstance(scriptObject);
                return ic;
            } catch (IllegalArgumentException e) {
                throw e;
            } catch (Exception e) {
                e.printStackTrace();
                throw new IllegalArgumentException(e.getMessage());
            }
        }
    }

    @Override
    public byte[] getBlockCallback19Offline(String method, String classname) {
        String mnamePath = classname + "BlockCallback$" + method + "xx1";
        ClassWriter cw = createBlockCtor19(mnamePath, classname);
        SkinnyMethodAdapter mv = startBlockCall19(cw);
        mv.line(-1);
        mv.aload(0);
        mv.getfield(mnamePath, "$scriptObject", "L" + classname + ";");
        mv.aloadMany(1, 2, 3, 4);
        mv.invokestatic(classname, method, sig(
                IRubyObject.class, "L" + classname + ";", ThreadContext.class,
                        IRubyObject.class, IRubyObject[].class, Block.class));
        mv.areturn();

        mv.visitMaxs(2, 3);
        return endCallOffline(cw, mv);
    }

    private SkinnyMethodAdapter startBlockCall(ClassWriter cw) {
        SkinnyMethodAdapter mv = new SkinnyMethodAdapter(cw.visitMethod(ACC_PUBLIC | ACC_SYNTHETIC | ACC_FINAL, "call", BLOCK_CALL_SIG, null, null));

        mv.visitCode();
        Label line = new Label();
        mv.visitLineNumber(0, line);
        return mv;
    }

    private SkinnyMethodAdapter startBlockCall19(ClassWriter cw) {
        SkinnyMethodAdapter mv = new SkinnyMethodAdapter(cw.visitMethod(ACC_PUBLIC | ACC_SYNTHETIC | ACC_FINAL, "call", BLOCK_CALL_SIG19, null, null));

        mv.visitCode();
        Label line = new Label();
        mv.visitLineNumber(0, line);
        return mv;
    }

    private ClassWriter createBlockCtor(String namePath, String classname) {
        String ciClassname = "L" + classname + ";";
        ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS | ClassWriter.COMPUTE_FRAMES);
        cw.visit(RubyInstanceConfig.JAVA_VERSION, ACC_PUBLIC + ACC_SUPER, namePath, null, p(CompiledBlockCallback.class), null);
        cw.visitField(ACC_PRIVATE | ACC_FINAL, "$scriptObject", ciClassname, null, null);
        SkinnyMethodAdapter mv = new SkinnyMethodAdapter(cw.visitMethod(ACC_PUBLIC, "<init>", sig(Void.TYPE, params(Object.class)), null, null));
        mv.start();
        mv.line(-1);
        mv.aload(0);
        mv.invokespecial(p(CompiledBlockCallback.class), "<init>", sig(void.class));
        mv.aloadMany(0, 1);
        mv.checkcast(classname);
        mv.putfield(namePath, "$scriptObject", ciClassname);
        mv.voidreturn();
        mv.end();

        return cw;
    }

    private ClassWriter createBlockCtor19(String namePath, String classname) {
        String ciClassname = "L" + classname + ";";
        ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS | ClassWriter.COMPUTE_FRAMES);
        cw.visit(RubyInstanceConfig.JAVA_VERSION, ACC_PUBLIC + ACC_SUPER, namePath, null, p(Object.class), new String[] {p(CompiledBlockCallback19.class)});
        cw.visitField(ACC_PRIVATE | ACC_FINAL, "$scriptObject", ciClassname, null, null);
        SkinnyMethodAdapter mv = new SkinnyMethodAdapter(cw.visitMethod(ACC_PUBLIC, "<init>", sig(Void.TYPE, params(Object.class)), null, null));
        mv.start();
        mv.line(-1);
        mv.aload(0);
        mv.invokespecial(p(Object.class), "<init>", sig(void.class));
        mv.aloadMany(0, 1);
        mv.checkcast(classname);
        mv.putfield(namePath, "$scriptObject", ciClassname);
        mv.voidreturn();
        mv.end();

        return cw;
    }

    /**
     * Use code generation to provide a method handle based on an annotated Java
     * method.
     * 
     * @see org.jruby.internal.runtime.methods.MethodFactory#getAnnotatedMethod
     */
    public void prepareAnnotatedMethod(RubyModule implementationClass, JavaMethod javaMethod, JavaMethodDescriptor desc) {
        String javaMethodName = desc.name;
        
        javaMethod.setArity(Arity.fromAnnotation(desc.anno, desc.actualRequired));
        javaMethod.setJavaName(javaMethodName);
        javaMethod.setSingleton(desc.isStatic);
        javaMethod.setCallConfig(CallConfiguration.getCallConfigByAnno(desc.anno));
    }

    /**
     * Emit code to check the arity of a call to a Java-based method.
     * 
     * @param jrubyMethod The annotation of the called method
     * @param method The code generator for the handle being created
     */
    private void checkArity(JRubyMethod jrubyMethod, SkinnyMethodAdapter method, int specificArity) {
        Label arityError = new Label();
        Label noArityError = new Label();
        
        switch (specificArity) {
        case 0:
        case 1:
        case 2:
        case 3:
            // for zero, one, two, three arities, JavaMethod.JavaMethod*.call(...IRubyObject[] args...) will check
            return;
        default:
            boolean checkArity = false;
            if (jrubyMethod.rest()) {
                if (jrubyMethod.required() > 0) {
                    // just confirm minimum args provided
                    method.aload(ARGS_INDEX);
                    method.arraylength();
                    method.ldc(jrubyMethod.required());
                    method.if_icmplt(arityError);
                    checkArity = true;
                }
            } else if (jrubyMethod.optional() > 0) {
                if (jrubyMethod.required() > 0) {
                    // confirm minimum args provided
                    method.aload(ARGS_INDEX);
                    method.arraylength();
                    method.ldc(jrubyMethod.required());
                    method.if_icmplt(arityError);
                }

                // confirm maximum not greater than optional
                method.aload(ARGS_INDEX);
                method.arraylength();
                method.ldc(jrubyMethod.required() + jrubyMethod.optional());
                method.if_icmpgt(arityError);
                checkArity = true;
            } else {
                // just confirm args length == required
                method.aload(ARGS_INDEX);
                method.arraylength();
                method.ldc(jrubyMethod.required());
                method.if_icmpne(arityError);
                checkArity = true;
            }

            if (checkArity) {
                method.go_to(noArityError);

                // Raise an error if arity does not match requirements
                method.label(arityError);
                method.aload(THREADCONTEXT_INDEX);
                method.invokevirtual(p(ThreadContext.class), "getRuntime", sig(Ruby.class));
                method.aload(ARGS_INDEX);
                method.ldc(jrubyMethod.required());
                method.ldc(jrubyMethod.required() + jrubyMethod.optional());
                method.invokestatic(p(Arity.class), "checkArgumentCount", sig(int.class, Ruby.class, IRubyObject[].class, int.class, int.class));
                method.pop();

                method.label(noArityError);
            }
        }
    }

    private ClassWriter createCompiledCtor(String namePath, String shortPath, String sup) {
        ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS | ClassWriter.COMPUTE_FRAMES);
        cw.visit(RubyInstanceConfig.JAVA_VERSION, ACC_PUBLIC + ACC_SUPER, namePath, null, sup, null);
        cw.visitSource(shortPath, null);
        SkinnyMethodAdapter mv = new SkinnyMethodAdapter(cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null));
        mv.visitCode();
        mv.line(-1);
        mv.aload(0);
        mv.visitMethodInsn(INVOKESPECIAL, sup, "<init>", "()V");
        mv.visitLineNumber(-1, new Label());
        mv.voidreturn();
        mv.end();

        return cw;
    }

    private ClassWriter createJavaMethodCtor(String namePath, String shortPath, String sup) throws Exception {
        ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS | ClassWriter.COMPUTE_FRAMES);
        cw.visit(RubyInstanceConfig.JAVA_VERSION, ACC_PUBLIC + ACC_SUPER, namePath, null, sup, null);
        cw.visitSource(namePath.replace('.', '/') + ".gen", null);
        SkinnyMethodAdapter mv = new SkinnyMethodAdapter(cw.visitMethod(ACC_PUBLIC, "<init>", JAVA_SUPER_SIG, null, null));
        mv.start();
        mv.line(-1);
        mv.aloadMany(0, 1, 2);
        mv.visitMethodInsn(INVOKESPECIAL, sup, "<init>", JAVA_SUPER_SIG);
        mv.visitLineNumber(-1, new Label());
        mv.voidreturn();
        mv.end();
        
        return cw;
    }

    private void invokeCallConfigPre(SkinnyMethodAdapter mv, String superClass, int specificArity, boolean block, CallConfiguration callConfig) {
        // invoke pre method stuff
        if (callConfig.isNoop()) return;

        prepareForPre(mv, specificArity, block, callConfig);
        mv.invokevirtual(superClass, getPreMethod(callConfig), getPreSignature(callConfig));
    }

    private void invokeCallConfigPost(SkinnyMethodAdapter mv, String superClass, CallConfiguration callConfig) {
        if (callConfig.isNoop()) return;

        mv.aload(1);
        mv.invokestatic(superClass, getPostMethod(callConfig), sig(void.class, params(ThreadContext.class)));
    }

    private void prepareForPre(SkinnyMethodAdapter mv, int specificArity, boolean block, CallConfiguration callConfig) {
        if (callConfig.isNoop()) return;
        
        mv.aloadMany(0, THREADCONTEXT_INDEX);
        
        switch (callConfig.framing()) {
        case Full:
            mv.aloadMany(RECEIVER_INDEX, NAME_INDEX); // self, name
            loadBlockForPre(mv, specificArity, block);
            break;
        case Backtrace:
            mv.aload(NAME_INDEX); // name
            break;
        case None:
            break;
        default: throw new RuntimeException("Unknown call configuration");
        }
    }

    private String getPreMethod(CallConfiguration callConfig) {
        switch (callConfig) {
        case FrameFullScopeFull: return "preFrameAndScope";
        case FrameFullScopeDummy: return "preFrameAndDummyScope";
        case FrameFullScopeNone: return "preFrameOnly";
        case FrameBacktraceScopeFull: return "preBacktraceAndScope";
        case FrameBacktraceScopeDummy: return "preBacktraceDummyscope";
        case FrameBacktraceScopeNone:  return "preBacktraceOnly";
        case FrameNoneScopeFull: return "preScopeOnly";
        case FrameNoneScopeDummy: return "preNoFrameDummyScope";
        case FrameNoneScopeNone: return "preNoop";
        default: throw new RuntimeException("Unknown call configuration");
        }
    }

    private String getPreSignature(CallConfiguration callConfig) {
        switch (callConfig) {
        case FrameFullScopeFull: return sig(void.class, params(ThreadContext.class, IRubyObject.class, String.class, Block.class));
        case FrameFullScopeDummy: return sig(void.class, params(ThreadContext.class, IRubyObject.class, String.class, Block.class));
        case FrameFullScopeNone: return sig(void.class, params(ThreadContext.class, IRubyObject.class, String.class, Block.class));
        case FrameBacktraceScopeFull: return sig(void.class, params(ThreadContext.class, String.class));
        case FrameBacktraceScopeDummy: return sig(void.class, params(ThreadContext.class, String.class));
        case FrameBacktraceScopeNone:  return sig(void.class, params(ThreadContext.class, String.class));
        case FrameNoneScopeFull: return sig(void.class, params(ThreadContext.class));
        case FrameNoneScopeDummy: return sig(void.class, params(ThreadContext.class));
        case FrameNoneScopeNone: return sig(void.class);
        default: throw new RuntimeException("Unknown call configuration");
        }
    }

    public static String getPostMethod(CallConfiguration callConfig) {
        switch (callConfig) {
        case FrameFullScopeFull: return "postFrameAndScope";
        case FrameFullScopeDummy: return "postFrameAndScope";
        case FrameFullScopeNone: return "postFrameOnly";
        case FrameBacktraceScopeFull: return "postBacktraceAndScope";
        case FrameBacktraceScopeDummy: return "postBacktraceDummyscope";
        case FrameBacktraceScopeNone:  return "postBacktraceOnly";
        case FrameNoneScopeFull: return "postScopeOnly";
        case FrameNoneScopeDummy: return "postNoFrameDummyScope";
        case FrameNoneScopeNone: return "postNoop";
        default: throw new RuntimeException("Unknown call configuration");
        }
    }

    private void loadArguments(SkinnyMethodAdapter mv, JavaMethodDescriptor desc, int specificArity) {
        switch (specificArity) {
        default:
        case -1:
            mv.aload(ARGS_INDEX);
            break;
        case 0:
            // no args
            break;
        case 1:
            loadArgumentWithCast(mv, 1, desc.argumentTypes[0]);
            break;
        case 2:
            loadArgumentWithCast(mv, 1, desc.argumentTypes[0]);
            loadArgumentWithCast(mv, 2, desc.argumentTypes[1]);
            break;
        case 3:
            loadArgumentWithCast(mv, 1, desc.argumentTypes[0]);
            loadArgumentWithCast(mv, 2, desc.argumentTypes[1]);
            loadArgumentWithCast(mv, 3, desc.argumentTypes[2]);
            break;
        }
    }

    private void loadArgumentWithCast(SkinnyMethodAdapter mv, int argNumber, Class coerceType) {
        mv.aload(ARGS_INDEX + (argNumber - 1));
        if (coerceType != IRubyObject.class && coerceType != IRubyObject[].class) {
            if (coerceType == RubyString.class) {
                mv.invokeinterface(p(IRubyObject.class), "convertToString", sig(RubyString.class));
            } else {
                throw new RuntimeException("Unknown coercion target: " + coerceType);
            }
        }
    }

    /** load block argument for pre() call.  Since we have fixed-arity call
     * paths we need calculate where the last var holding the block is.
     *
     * is we don't have a block we setup NULL_BLOCK as part of our null pattern
     * strategy (we do not allow null in any field which accepts block).
     */
    private void loadBlockForPre(SkinnyMethodAdapter mv, int specificArity, boolean getsBlock) {
        if (!getsBlock) {            // No block so load null block instance
            mv.getstatic(p(Block.class), "NULL_BLOCK", ci(Block.class));
            return;
        }

        loadBlock(mv, specificArity, getsBlock);
    }

    /** load the block argument from the correct position.  Since we have fixed-
     * arity call paths we need to calculate where the last var holding the
     * block is.
     * 
     * If we don't have a block then this does nothing.
     */
    private void loadBlock(SkinnyMethodAdapter mv, int specificArity, boolean getsBlock) {
        if (!getsBlock) return;         // No block so nothing more to do
        
        switch (specificArity) {        // load block since it accepts a block
        case 0: case 1: case 2: case 3: // Fixed arities signatures
            mv.aload(BLOCK_INDEX - 1 + specificArity);
            break;
        default: case -1:
            mv.aload(BLOCK_INDEX);      // Generic arity signature
            break;
        }
    }

    private void loadReceiver(String typePath, JavaMethodDescriptor desc, SkinnyMethodAdapter mv) {
        // load target for invocations
        if (Modifier.isStatic(desc.modifiers)) {
            if (desc.hasContext) {
                mv.aload(THREADCONTEXT_INDEX);
            }
            
            // load self object as IRubyObject, for recv param
            mv.aload(RECEIVER_INDEX);
        } else {
            // load receiver as original type for virtual invocation
            mv.aload(RECEIVER_INDEX);
            mv.checkcast(typePath);
            
            if (desc.hasContext) {
                mv.aload(THREADCONTEXT_INDEX);
            }
        }
    }
    private Class tryClass(String name, Class targetClass) {
        try {
            Class c = null;
            if (classLoader == null) {
                c = Class.forName(name, true, classLoader);
            } else {
                c = classLoader.loadClass(name);
            }
            
            if (c != null && seenUndefinedClasses && !haveWarnedUser) {
                haveWarnedUser = true;
                System.err.println("WARNING: while creating new bindings for " + targetClass + ",\n" +
                        "found an existing binding; you may want to run a clean build.");
            }
            
            return c;
        } catch(Exception e) {
            seenUndefinedClasses = true;
            return null;
        }
    }

    private Class tryClass(String name) {
        try {
            return classLoader.loadClass(name);
        } catch (Exception e) {
            return null;
        }
    }

    protected Class endCall(ClassWriter cw, MethodVisitor mv, String name) {
        endMethod(mv);
        return endClass(cw, name);
    }

    protected Class endCallWithBytes(byte[] classBytes, String name) {
        return endClassWithBytes(classBytes, name);
    }

    protected byte[] endCallOffline(ClassWriter cw, MethodVisitor mv) {
        endMethod(mv);
        return endClassOffline(cw);
    }

    protected void endMethod(MethodVisitor mv) {
        mv.visitMaxs(0,0);
        mv.visitEnd();
    }

    protected Class endClass(ClassWriter cw, String name) {
        cw.visitEnd();
        byte[] code = cw.toByteArray();
        if (DEBUG) CheckClassAdapter.verify(new ClassReader(code), false, new PrintWriter(System.err));
         
        return classLoader.defineClass(name, code);
    }

    protected Class endClassWithBytes(byte[] code, String name) {
        return classLoader.defineClass(name, code);
    }

    protected byte[] endClassOffline(ClassWriter cw) {
        cw.visitEnd();
        byte[] code = cw.toByteArray();
        if (DEBUG) CheckClassAdapter.verify(new ClassReader(code), false, new PrintWriter(System.err));

        return code;
    }
    
    private SkinnyMethodAdapter beginMethod(ClassWriter cw, String methodName, int specificArity, boolean block) {
        switch (specificArity) {
        default:
        case -1:
            if (block) {
                return new SkinnyMethodAdapter(cw.visitMethod(ACC_PUBLIC, methodName, COMPILED_CALL_SIG_BLOCK, null, null));
            } else {
                return new SkinnyMethodAdapter(cw.visitMethod(ACC_PUBLIC, methodName, COMPILED_CALL_SIG, null, null));
            }
        case 0:
            if (block) {
                return new SkinnyMethodAdapter(cw.visitMethod(ACC_PUBLIC, methodName, COMPILED_CALL_SIG_ZERO_BLOCK, null, null));
            } else {
                return new SkinnyMethodAdapter(cw.visitMethod(ACC_PUBLIC, methodName, COMPILED_CALL_SIG_ZERO, null, null));
            }
        case 1:
            if (block) {
                return new SkinnyMethodAdapter(cw.visitMethod(ACC_PUBLIC, methodName, COMPILED_CALL_SIG_ONE_BLOCK, null, null));
            } else {
                return new SkinnyMethodAdapter(cw.visitMethod(ACC_PUBLIC, methodName, COMPILED_CALL_SIG_ONE, null, null));
            }
        case 2:
            if (block) {
                return new SkinnyMethodAdapter(cw.visitMethod(ACC_PUBLIC, methodName, COMPILED_CALL_SIG_TWO_BLOCK, null, null));
            } else {
                return new SkinnyMethodAdapter(cw.visitMethod(ACC_PUBLIC, methodName, COMPILED_CALL_SIG_TWO, null, null));
            }
        case 3:
            if (block) {
                return new SkinnyMethodAdapter(cw.visitMethod(ACC_PUBLIC, methodName, COMPILED_CALL_SIG_THREE_BLOCK, null, null));
            } else {
                return new SkinnyMethodAdapter(cw.visitMethod(ACC_PUBLIC, methodName, COMPILED_CALL_SIG_THREE, null, null));
            }
        }
    }
    
    private Class selectSuperClass(int specificArity, boolean block) {
        switch (specificArity) {
        default: case -1:
            return block ? JavaMethod.class :
                JavaMethod.JavaMethodN.class;
        case 0:
            return block ? JavaMethod.JavaMethodZeroBlock.class :
                JavaMethod.JavaMethodZero.class;
        case 1:
            return block ? JavaMethod.JavaMethodOneBlock.class :
                JavaMethod.JavaMethodOne.class;
        case 2:
            return block ? JavaMethod.JavaMethodTwoBlock.class :
                JavaMethod.JavaMethodTwo.class;
        case 3:
            return block ? JavaMethod.JavaMethodThreeBlock.class :
                JavaMethod.JavaMethodThree.class;
        }
    }

    private void createAnnotatedMethodInvocation(JavaMethodDescriptor desc, SkinnyMethodAdapter method, String superClass, int specificArity, boolean block) {
        String typePath = desc.declaringClassPath;
        String javaMethodName = desc.name;

        checkArity(desc.anno, method, specificArity);
        
        CallConfiguration callConfig = CallConfiguration.getCallConfigByAnno(desc.anno);
        if (!callConfig.isNoop()) {
            invokeCallConfigPre(method, superClass, specificArity, block, callConfig);
        }

        int traceBoolIndex = -1;
        if (RubyInstanceConfig.FULL_TRACE_ENABLED) {
            // load and store trace enabled flag
            switch (specificArity) {
            case -1:
                traceBoolIndex = ARGS_INDEX + (block ? 1 : 0) + 1;
                break;
            case 0:
                traceBoolIndex = ARGS_INDEX + (block ? 1 : 0);
                break;
            default:
                traceBoolIndex = ARGS_INDEX + specificArity + (block ? 1 : 0) + 1;
            }

            method.aload(1);
            method.invokevirtual(p(ThreadContext.class), "getRuntime", sig(Ruby.class));
            method.invokevirtual(p(Ruby.class), "hasEventHooks", sig(boolean.class));
            method.istore(traceBoolIndex);

            // call trace
            invokeCCallTrace(method, traceBoolIndex);
        }

        Label tryBegin = new Label();
        Label tryEnd = new Label();
        Label doFinally = new Label();

        if (!callConfig.isNoop()) {
            method.trycatch(tryBegin, tryEnd, doFinally, null);
        }
        
        method.label(tryBegin);
        {
            loadReceiver(typePath, desc, method);
            
            loadArguments(method, desc, specificArity);
            
            loadBlock(method, specificArity, block);

            if (Modifier.isStatic(desc.modifiers)) {
                // static invocation
                method.invokestatic(typePath, javaMethodName, desc.signature);
            } else {
                // virtual invocation
                method.invokevirtual(typePath, javaMethodName, desc.signature);
            }

            if (desc.getReturnClass() == void.class) {
                // void return type, so we need to load a nil for returning below
                method.aload(THREADCONTEXT_INDEX);
                method.invokevirtual(p(ThreadContext.class), "getRuntime", sig(Ruby.class));
                method.invokevirtual(p(Ruby.class), "getNil", sig(IRubyObject.class));
            }
        }
        method.label(tryEnd);
        
        // normal finally and exit
        {
            if (RubyInstanceConfig.FULL_TRACE_ENABLED) {
                invokeCReturnTrace(method, traceBoolIndex);
            }
            
            if (!callConfig.isNoop()) {
                invokeCallConfigPost(method, superClass, callConfig);
            }

            // return
            method.visitInsn(ARETURN);
        }
        
        // these are only needed if we have a non-noop call config
        if (!callConfig.isNoop()) {
            // finally handling for abnormal exit
            {
                method.label(doFinally);
                
                if (RubyInstanceConfig.FULL_TRACE_ENABLED) {
                    invokeCReturnTrace(method, traceBoolIndex);
                }

                //call post method stuff (exception raised)
                if (!callConfig.isNoop()) {
                    invokeCallConfigPost(method, superClass, callConfig);
                }

                // rethrow exception
                method.athrow(); // rethrow it
            }
        }
    }

    private void invokeCCallTrace(SkinnyMethodAdapter method, int traceBoolIndex) {
        method.aloadMany(0, 1); // method, threadContext
        method.iload(traceBoolIndex); // traceEnable
        method.aload(4); // invokedName
        method.invokevirtual(p(JavaMethod.class), "callTrace", sig(void.class, ThreadContext.class, boolean.class, String.class));
    }
    
    private void invokeCReturnTrace(SkinnyMethodAdapter method, int traceBoolIndex) {
        method.aloadMany(0, 1); // method, threadContext
        method.iload(traceBoolIndex); // traceEnable
        method.aload(4); // invokedName
        method.invokevirtual(p(JavaMethod.class), "returnTrace", sig(void.class, ThreadContext.class, boolean.class, String.class));
    }

    private void invokeTraceCompiledPre(SkinnyMethodAdapter mv, String superClass, int traceBoolIndex, String filename, int line) {
        mv.aloadMany(0, 1); // method, threadContext
        mv.iload(traceBoolIndex); // traceEnable
        mv.aload(4); // invokedName
        mv.ldc(filename);
        mv.ldc(line);
        mv.invokevirtual(superClass, "callTraceCompiled", sig(void.class, ThreadContext.class, boolean.class, String.class, String.class, int.class));
    }

    private void invokeTraceCompiledPost(SkinnyMethodAdapter mv, String superClass, int traceBoolIndex) {
        mv.aloadMany(0, 1); // method, threadContext
        mv.iload(traceBoolIndex); // traceEnable
        mv.aload(4); // invokedName
        mv.invokevirtual(superClass, "returnTraceCompiled", sig(void.class, ThreadContext.class, boolean.class, String.class));
    }
}
