Example usage for org.objectweb.asm MethodVisitor visitInsn

List of usage examples for org.objectweb.asm MethodVisitor visitInsn

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Introduction

In this page you can find the example usage for org.objectweb.asm MethodVisitor visitInsn.

Prototype

public void visitInsn(final int opcode)

Source Link

Document

Visits a zero operand instruction.

Usage

From source file:com.cinnober.msgcodec.blink.BaseByteCodeGenerator.java

License:Open Source License

protected void generateEncodeEnumValue(TypeDef.Enum enumType, String genClassInternalName,
        String fieldIdentifier, LocalVariable nextVar, Class<?> javaClass, boolean required, MethodVisitor mv,
        String debugValueLabel) throws IllegalArgumentException {

    Label writeValueLabel = new Label();

    // Make sure that no unsupported javaClass is used for an enum
    if (javaClass != int.class && javaClass != Integer.class && (javaClass == null || !javaClass.isEnum())) {
        throw new IllegalArgumentException("Illegal enum javaClass: " + javaClass);
    }/*from ww w  . j ava  2s .c  o m*/

    // If null do not look it up
    if (!required) {
        Label lookupIdLabel = new Label();
        mv.visitInsn(DUP);
        mv.visitJumpInsn(IFNONNULL, lookupIdLabel);

        // null
        mv.visitInsn(POP);
        mv.visitInsn(ACONST_NULL);
        mv.visitJumpInsn(GOTO, writeValueLabel);

        // not null
        mv.visitLabel(lookupIdLabel);
    }

    // SymbolMapping
    if (required && !javaClass.isEnum()) {
        box(mv, int.class);
    }
    mv.visitVarInsn(ALOAD, 0);
    mv.visitFieldInsn(GETFIELD, genClassInternalName, "symbolMapping_" + fieldIdentifier,
            "Lcom/cinnober/msgcodec/SymbolMapping;");
    mv.visitInsn(SWAP);
    mv.visitMethodInsn(INVOKEINTERFACE, "com/cinnober/msgcodec/SymbolMapping", "getId",
            "(Ljava/lang/Object;)Ljava/lang/Integer;", true);

    // Write the value
    mv.visitLabel(writeValueLabel);
    if (required) {
        unbox(mv, Integer.class); // TODO: Should null check before this and throw exception since there was no mapping
    }
    generateEncodeInt32Value(required, mv);

    //        if (javaClass.isEnum()) {
    //            Label endLabel = new Label();
    //            if (!required) {
    //                Label nonNullLabel = new Label();
    //                mv.visitInsn(DUP);
    //                mv.visitJumpInsn(IFNONNULL, nonNullLabel);
    //                // null
    //                mv.visitInsn(POP);
    //                mv.visitInsn(ACONST_NULL);
    //                mv.visitMethodInsn(INVOKESTATIC, blinkOutputIName, "writeInt32Null",
    //                        "(Lcom/cinnober/msgcodec/io/ByteSink;Ljava/lang/Integer;)V", false);
    //                mv.visitJumpInsn(GOTO, endLabel);
    //                // not null
    //                mv.visitLabel(nonNullLabel);
    //            }
    //            mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Enum", "ordinal", "()I", false);
    //            //switch
    //            EnumSymbols enumSymbols = new EnumSymbols(enumType, javaClass);
    //            Enum[] enumValues = ((Class<Enum>)javaClass).getEnumConstants();
    //            int[] ordinals = new int[enumValues.length];
    //            Label[] labels = new Label[enumValues.length];
    //            for (int i=0; i<enumValues.length; i++) {
    //                ordinals[i] = i;
    //                labels[i] = new Label();
    //            }
    //            Label defaultLabel = new Label();
    //            Label writeLabel = new Label();
    //            int symbolIdVar = nextVar.next();
    //            mv.visitLookupSwitchInsn(defaultLabel, ordinals, labels);
    //            for (int i=0; i<enumValues.length; i++) {
    //                mv.visitLabel(labels[i]);
    //                Symbol symbol = enumSymbols.getSymbol(enumValues[i]);
    //                if (symbol != null) {
    //                    mv.visitLdcInsn(symbol.getId());
    //                    mv.visitJumpInsn(GOTO, writeLabel);
    //                } else {
    //                    mv.visitLdcInsn(debugValueLabel);
    //                    mv.visitVarInsn(ALOAD, symbolIdVar);
    //                    mv.visitMethodInsn(INVOKESTATIC, baseclassIName, "unmappableEnumSymbolValue",
    //                            "(Ljava/lang/String;Ljava/lang/Enum;)Ljava/lang/IllegalArgumentException;", false);
    //                    mv.visitInsn(ATHROW);
    //                }
    //            }
    //            mv.visitLabel(defaultLabel);
    //            mv.visitTypeInsn(NEW, "java/lang/RuntimeException");
    //            mv.visitInsn(DUP);
    //            mv.visitLdcInsn("Should not happen: reached generated switch default case for value " + debugValueLabel);
    //            mv.visitMethodInsn(INVOKESPECIAL, "java/lang/RuntimeException", "<init>", "(Ljava/lang/String;)V", false);
    //            mv.visitInsn(ATHROW);
    //
    //            // write
    //            mv.visitLabel(writeLabel);
    //            if (!required) {
    //                box(mv, int.class);
    //            }
    //            generateEncodeInt32Value(required, mv);
    //            // end
    //            mv.visitLabel(endLabel);
    //        } else if (javaClass == int.class || javaClass == Integer.class) {
    //            generateEncodeInt32Value(required, mv);
    //        } else {
    //            throw new IllegalArgumentException("Illegal enum javaClass: " + javaClass);
    //        }
}

From source file:com.cinnober.msgcodec.blink.BaseByteCodeGenerator.java

License:Open Source License

/**
 * Generate value decoding using the blink input.
 *
 * <p>Defaults to <code>readUInt16[Null].</code>
 *
 * @param required true if the field is required, otherwise false.
 * @param mv the method visitor, not null.
 * @see #generateDecodeValue//from  ww w . j  a  v  a2 s . c o  m
 */
protected void generateDecodeCharacterValue(boolean required, MethodVisitor mv) {
    if (required) {
        mv.visitMethodInsn(INVOKESTATIC, blinkInputIName, "readUInt16",
                "(Lcom/cinnober/msgcodec/io/ByteSource;)S", false);
        mv.visitInsn(I2C);
    } else {
        mv.visitMethodInsn(INVOKESTATIC, blinkInputIName, "readUInt16Null",
                "(Lcom/cinnober/msgcodec/io/ByteSource;)Ljava/lang/Short;", false);
        Label nullLabel = new Label();
        mv.visitInsn(DUP);
        mv.visitJumpInsn(IFNULL, nullLabel);
        unbox(mv, Short.class);
        mv.visitInsn(I2C);
        box(mv, Character.class);
        mv.visitLabel(nullLabel);
        mv.visitTypeInsn(CHECKCAST, Type.getInternalName(Character.class));
    }
}

From source file:com.cinnober.msgcodec.blink.BaseByteCodeGenerator.java

License:Open Source License

protected void generateDecodeTimeValue(TypeDef.Time type, Class<?> javaClass, boolean required,
        MethodVisitor mv, LocalVariable nextVar) throws IllegalArgumentException {
    if (javaClass == long.class || javaClass == Long.class) {
        generateDecodeInt64Value(required, mv);
    } else if (javaClass == int.class || javaClass == Integer.class) {
        generateDecodeInt32Value(required, mv);
    } else if (javaClass == Date.class) {

        int timeVar = nextVar.next();
        nextVar.next(); // note: 2 variable slots
        Label endLabel = new Label();
        if (required) {
            generateDecodeInt64Value(true, mv);
        } else {/*from   w w  w .j  a  va2  s  .co  m*/
            generateDecodeInt64Value(false, mv);
            mv.visitInsn(DUP);
            Label nonNullLabel = new Label();
            mv.visitJumpInsn(IFNONNULL, nonNullLabel);
            // null
            mv.visitTypeInsn(CHECKCAST, "java/util/Date");
            mv.visitJumpInsn(GOTO, endLabel);
            // not null
            mv.visitLabel(nonNullLabel);
            mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Long", "longValue", "()J", false);
        }

        mv.visitVarInsn(LSTORE, timeVar);
        mv.visitTypeInsn(NEW, "java/util/Date");
        mv.visitInsn(DUP);
        mv.visitVarInsn(LLOAD, timeVar);
        // handle differences in UNIT and EPOCH
        long epochOffset = DateUtil.getEpochOffset(type.getEpoch());
        long timeInMillis = DateUtil.getTimeInMillis(type.getUnit());
        // dateTime = wireTime * timeUnitInMillis + epochOffset;
        if (timeInMillis != 1) {
            mv.visitLdcInsn(timeInMillis);
            mv.visitInsn(LMUL);
        }
        if (epochOffset != 0) {
            mv.visitLdcInsn(epochOffset);
            mv.visitInsn(LADD);
        }

        mv.visitMethodInsn(INVOKESPECIAL, "java/util/Date", "<init>", "(J)V", false);

        if (!required) {
            // end
            mv.visitLabel(endLabel);
        }
    } else {
        throw new IllegalArgumentException("Illegal time javaClass: " + javaClass);
    }
}

From source file:com.cinnober.msgcodec.blink.BaseByteCodeGenerator.java

License:Open Source License

/**
 * @see #generateDecodeInt32Value(boolean, org.objectweb.asm.MethodVisitor) 
 *///  w ww  .  j a  va  2  s .co  m
protected void generateDecodeEnumValue(boolean required, MethodVisitor mv, TypeDef type,
        String genClassInternalName, String fieldIdentifier, LocalVariable nextVar, Class<?> javaClass,
        String debugValueLabel) throws IllegalArgumentException {

    Label endLabel = new Label();
    if (required) {
        generateDecodeInt32Value(true, mv);
        box(mv, Integer.class);
    } else {
        generateDecodeInt32Value(false, mv);
        mv.visitInsn(DUP);
        mv.visitJumpInsn(IFNULL, endLabel);

        //            Label nonNullLabel = new Label();
        //            mv.visitJumpInsn(IFNONNULL, nonNullLabel);
        //            mv.visitTypeInsn(CHECKCAST, Type.getInternalName(javaClass));
        //            mv.visitJumpInsn(GOTO, endLabel);

        // not null
        //            mv.visitLabel(nonNullLabel);
        //            mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Integer", "intValue", "()I", false); // unbox(mv, Integer.class);
    }

    // SymbolMapping
    mv.visitVarInsn(ALOAD, 0);
    mv.visitFieldInsn(GETFIELD, genClassInternalName, "symbolMapping_" + fieldIdentifier,
            "Lcom/cinnober/msgcodec/SymbolMapping;");
    mv.visitInsn(SWAP);
    mv.visitMethodInsn(INVOKEINTERFACE, "com/cinnober/msgcodec/SymbolMapping", "lookup",
            "(Ljava/lang/Integer;)Ljava/lang/Object;", true);

    //        // switch
    //        TypeDef.Enum enumType = (TypeDef.Enum) type;
    //        List<Symbol> symbols = enumType.getSymbols();
    //        int numSymbols = symbols.size();
    //        int[] ids = new int[numSymbols];
    //        Label[] labels = new Label[numSymbols];
    //        for (int i=0; i<numSymbols; i++) {
    //            ids[i] = symbols.get(i).getId();
    //            labels[i] = new Label();
    //        }
    //        Label defaultLabel = new Label();
    //        int symbolIdVar = nextVar.next();
    //        mv.visitInsn(DUP);
    //        mv.visitVarInsn(ISTORE, symbolIdVar);
    //        EnumSymbols enumSymbols = null;
    //        if (javaClass.isEnum()) {
    //            enumSymbols = new EnumSymbols(enumType, javaClass);
    //        }
    //        mv.visitLookupSwitchInsn(defaultLabel, ids, labels);
    //        for (int i=0; i<numSymbols; i++) {
    //            boolean addGotoEnd = true;
    //            mv.visitLabel(labels[i]);
    //            if (javaClass.isEnum()) {
    //                Enum enumValue = enumSymbols.getEnum(ids[i]);
    //                if (enumValue != null) {
    //                    //mv.visitLdcInsn(Type.getType(javaClass));
    //                    mv.visitFieldInsn(GETSTATIC, Type.getInternalName(javaClass),
    //                            enumValue.name(),
    //                            Type.getDescriptor(javaClass));
    //                } else {
    //                    mv.visitLdcInsn(debugValueLabel);
    //                    mv.visitLdcInsn(ids[i]);
    //                    mv.visitLdcInsn(Type.getType(javaClass));
    //                    mv.visitMethodInsn(INVOKESTATIC, baseclassIName, "unmappableEnumSymbolId",
    //                            "(Ljava/lang/String;ILjava/lang/Class;)Lcom/cinnober/msgcodec/DecodeException;", false);
    //                    mv.visitInsn(ATHROW);
    //                    addGotoEnd = false;
    //                }
    //            } else if (javaClass == int.class || javaClass == Integer.class) {
    //                mv.visitLdcInsn(ids[i]);
    //                if (!required) {
    //                    box(mv, Integer.class);
    //                }
    //            } else {
    //                throw new IllegalArgumentException("Illegal enum javaClass: " + javaClass);
    //            }
    //            if (addGotoEnd) {
    //                mv.visitJumpInsn(GOTO, endLabel);
    //            }
    //        }
    //        mv.visitLabel(defaultLabel);
    //        mv.visitLdcInsn(debugValueLabel);
    //        mv.visitVarInsn(ILOAD, symbolIdVar);
    //        mv.visitMethodInsn(INVOKESTATIC, baseclassIName, "unknownEnumSymbol",
    //                "(Ljava/lang/String;I)Lcom/cinnober/msgcodec/DecodeException;", false);
    //        mv.visitInsn(ATHROW);

    // end
    mv.visitLabel(endLabel);

    if (!javaClass.isEnum()) {
        mv.visitTypeInsn(CHECKCAST, Type.getInternalName(Integer.class));
        if (required) {
            unbox(mv, Integer.class);
        }
    } else {
        mv.visitTypeInsn(CHECKCAST, Type.getInternalName(javaClass));
    }
}

From source file:com.cinnober.msgcodec.blink.BaseByteCodeGenerator.java

License:Open Source License

protected void generateDecodeDynRefValue(MethodVisitor mv, boolean required, GroupDef refGroup,
        Class<?> javaClass) {
    mv.visitVarInsn(ALOAD, 0); // this
    mv.visitInsn(SWAP); // this and in
    if (required) {
        mv.visitMethodInsn(INVOKEVIRTUAL, baseclassIName, "readDynamicGroup",
                "(Lcom/cinnober/msgcodec/io/ByteSource;)Ljava/lang/Object;", false);
    } else {/*from   w ww  . j  a va 2  s.  c  om*/
        mv.visitMethodInsn(INVOKEVIRTUAL, baseclassIName, "readDynamicGroupNull",
                "(Lcom/cinnober/msgcodec/io/ByteSource;)Ljava/lang/Object;", false);
    }
    if (refGroup != null) {
        mv.visitTypeInsn(CHECKCAST, Type.getInternalName(javaClass));
    }
}

From source file:com.cinnober.msgcodec.blink.BaseByteCodeGenerator.java

License:Open Source License

protected void generateDecodeRefValue(GroupDef refGroup, boolean required, MethodVisitor mv, int byteSourceVar,
        String genClassInternalName, Class<?> javaClass, TypeDef type, boolean javaClassCodec)
        throws IllegalArgumentException {
    if (refGroup != null) {
        String groupDescriptor = getTypeDescriptor(javaClass, javaClassCodec);
        if (required) {
            mv.visitInsn(POP); // input stream
            mv.visitVarInsn(ALOAD, 0);//from  w  ww  . j ava  2  s  .co m
            mv.visitVarInsn(ALOAD, byteSourceVar);
            mv.visitMethodInsn(INVOKEVIRTUAL, genClassInternalName, "readStaticGroup_" + refGroup.getName(),
                    "(Lcom/cinnober/msgcodec/io/ByteSource;)" + groupDescriptor, false);
        } else {
            mv.visitMethodInsn(INVOKESTATIC, blinkInputIName, "readPresenceByte",
                    "(Lcom/cinnober/msgcodec/io/ByteSource;)Z", false);
            Label nonNullLabel = new Label();
            Label endLabel = new Label();
            mv.visitJumpInsn(IFNE, nonNullLabel); // not false, i.e. true
            // null
            mv.visitInsn(ACONST_NULL);
            mv.visitJumpInsn(GOTO, endLabel);

            // not null
            mv.visitLabel(nonNullLabel);
            mv.visitFrame(F_SAME, 0, null, 0, null);
            mv.visitVarInsn(ALOAD, 0);
            mv.visitVarInsn(ALOAD, byteSourceVar);
            mv.visitMethodInsn(INVOKEVIRTUAL, genClassInternalName, "readStaticGroup_" + refGroup.getName(),
                    "(Lcom/cinnober/msgcodec/io/ByteSource;)" + groupDescriptor, false);

            mv.visitLabel(endLabel);
            // PENDING: mv.visitFrame?
            mv.visitFrame(F_SAME, 0, null, 0, null);
        }
    } else {
        throw new IllegalArgumentException("Illegal reference: " + type);
    }
}

From source file:com.cinnober.msgcodec.blink.BaseByteCodeGenerator.java

License:Open Source License

protected void generateDecodeSequenceValue(Class<?> javaClass, LocalVariable nextVar, boolean required,
        MethodVisitor mv, Class<?> componentJavaClass, int byteSourceVar, TypeDef type, Schema schema,
        String genClassInternalName, String fieldIdentifier, String debugValueLabel, boolean javaClassCodec)
        throws IllegalArgumentException {
    if (!javaClass.isArray() && javaClass != List.class) {
        throw new IllegalArgumentException("Illegal sequence javaClass: " + javaClass);
    }/*from w w w. j  ava2  s  .c o m*/

    int lengthVar = nextVar.next();
    int sequenceVar = nextVar.next();
    Label finalEndLabel = new Label();
    if (required) {
        mv.visitMethodInsn(INVOKESTATIC, blinkInputIName, "readUInt32",
                "(Lcom/cinnober/msgcodec/io/ByteSource;)I", false);
        mv.visitVarInsn(ISTORE, lengthVar);
    } else {
        mv.visitMethodInsn(INVOKESTATIC, blinkInputIName, "readUInt32Null",
                "(Lcom/cinnober/msgcodec/io/ByteSource;)Ljava/lang/Integer;", false);
        mv.visitInsn(DUP);
        mv.visitJumpInsn(IFNULL, finalEndLabel);
        unbox(mv, Integer.class);
        mv.visitVarInsn(ISTORE, lengthVar);
    }

    if (javaClass.isArray()) {
        mv.visitVarInsn(ILOAD, lengthVar);
        generateNewArray(mv, componentJavaClass);
    } else {
        mv.visitTypeInsn(NEW, "java/util/ArrayList");
        mv.visitInsn(DUP);
        mv.visitVarInsn(ILOAD, lengthVar);
        mv.visitMethodInsn(INVOKESPECIAL, "java/util/ArrayList", "<init>", "(I)V", false);
    }
    mv.visitVarInsn(ASTORE, sequenceVar);

    // for loop
    Label endLabel = new Label();
    int loopVar = nextVar.next();
    mv.visitInsn(ICONST_0);
    mv.visitVarInsn(ISTORE, loopVar);
    Label loopLabel = new Label();
    mv.visitLabel(loopLabel);
    // PENDING: mv.visitFrame?
    mv.visitFrame(F_SAME, 0, null, 0, null);
    mv.visitVarInsn(ILOAD, loopVar);
    mv.visitVarInsn(ILOAD, lengthVar);
    mv.visitJumpInsn(IF_ICMPGE, endLabel);

    mv.visitVarInsn(ALOAD, sequenceVar);
    mv.visitVarInsn(ILOAD, loopVar);
    mv.visitVarInsn(ALOAD, byteSourceVar);

    // decode the element
    TypeDef.Sequence seqType = (TypeDef.Sequence) type;
    generateDecodeValue(mv, byteSourceVar, nextVar, true, seqType.getComponentType(), componentJavaClass, null,
            schema, genClassInternalName, fieldIdentifier, debugValueLabel + ".component", javaClassCodec);

    // store the value
    if (javaClass.isArray()) {
        generateArrayStore(mv, componentJavaClass);
    } else {
        mv.visitMethodInsn(INVOKEVIRTUAL, "java/util/ArrayList", "add", "(ILjava/lang/Object;)V", false);
    }

    mv.visitIincInsn(loopVar, 1);
    mv.visitJumpInsn(GOTO, loopLabel);
    mv.visitLabel(endLabel);
    mv.visitFrame(F_SAME, 0, null, 0, null);
    mv.visitVarInsn(ALOAD, sequenceVar);
    mv.visitLabel(finalEndLabel);
    mv.visitFrame(F_SAME, 0, null, 0, null);
    if (javaClass.isArray()) {
        mv.visitTypeInsn(CHECKCAST, Type.getInternalName(javaClass));
    }
}

From source file:com.cinnober.msgcodec.blink.BaseByteCodeGenerator.java

License:Open Source License

public static void generateArrayStore(MethodVisitor mv, Class<?> componentJavaClass) {
    if (componentJavaClass == byte.class || componentJavaClass == boolean.class) {
        mv.visitInsn(BASTORE);
    } else if (componentJavaClass == short.class) {
        mv.visitInsn(SASTORE);/*from   w ww . jav a  2 s . com*/
    } else if (componentJavaClass == int.class) {
        mv.visitInsn(IASTORE);
    } else if (componentJavaClass == long.class) {
        mv.visitInsn(LASTORE);
    } else if (componentJavaClass == float.class) {
        mv.visitInsn(FASTORE);
    } else if (componentJavaClass == double.class) {
        mv.visitInsn(DASTORE);
    } else if (componentJavaClass == char.class) {
        mv.visitInsn(CASTORE);
    } else {
        mv.visitInsn(AASTORE);
    }
}

From source file:com.cinnober.msgcodec.blink.NativeByteCodeGenerator.java

License:Open Source License

@Override
protected void generateWriteStaticGroupForTypeWithId(Schema schema, ClassVisitor cv,
        String genClassInternalName, boolean javaClassCodec) {
    for (GroupDef group : schema.getGroups()) {
        Object groupType = group.getGroupType();
        String groupDescriptor = getTypeDescriptor(groupType, javaClassCodec);
        MethodVisitor mv = cv.visitMethod(ACC_PRIVATE, "writeStaticGroupWithId_" + group.getName(),
                "(Lcom/cinnober/msgcodec/io/ByteSink;" + groupDescriptor + ")V", null,
                new String[] { "java/io/IOException" });
        mv.visitCode();//  w  ww.  j a v  a  2  s.co  m
        int nextWriteidVar = 3;

        if (group.getId() != -1) {
            // write with id
            mv.visitVarInsn(ALOAD, 1); // out
            mv.visitLdcInsn(group.getId() & 0xffffffffL);
            mv.visitMethodInsn(INVOKESTATIC, blinkOutputIName, "writeUInt64",
                    "(Lcom/cinnober/msgcodec/io/ByteSink;J)V", false);

            // add extension offset (four zero bytes)
            mv.visitVarInsn(ALOAD, 1); // out
            mv.visitInsn(ICONST_0);
            generateEncodeUInt32Value(true, mv);

            mv.visitVarInsn(ALOAD, 0); // this
            mv.visitVarInsn(ALOAD, 1); // out
            mv.visitVarInsn(ALOAD, 2); // obj
            mv.visitMethodInsn(INVOKEVIRTUAL, genClassInternalName, "writeStaticGroup_" + group.getName(),
                    "(Lcom/cinnober/msgcodec/io/ByteSink;" + groupDescriptor + ")V", false);
            mv.visitInsn(RETURN);
        } else {
            // write with id
            mv.visitTypeInsn(NEW, "java/lang/IllegalArgumentException");
            mv.visitInsn(DUP);
            mv.visitLdcInsn("No group id");
            mv.visitMethodInsn(INVOKESPECIAL, "java/lang/IllegalArgumentException", "<init>",
                    "(Ljava/lang/String;)V", false);
            mv.visitInsn(ATHROW);
        }

        // end
        mv.visitMaxs(3, nextWriteidVar);
        mv.visitEnd();
    }
}

From source file:com.e2info.helloasm.HelloAsmApp.java

License:Open Source License

public static void main(String[] args) throws IOException {
    String name = "HelloAsm";
    int flag = ClassWriter.COMPUTE_MAXS;
    ClassWriter cw = new ClassWriter(flag);
    cw.visit(Opcodes.V1_5, Opcodes.ACC_PUBLIC + Opcodes.ACC_SUPER, name, null, "java/lang/Object", null);

    cw.visitSource(name + ".java", null);

    {/*from  w  w  w . j a  v  a 2  s.co  m*/
        MethodVisitor mv;
        mv = cw.visitMethod(Opcodes.ACC_PUBLIC, "<init>", "()V", null, null);
        mv.visitCode();
        mv.visitVarInsn(Opcodes.ALOAD, 0);
        mv.visitMethodInsn(Opcodes.INVOKESPECIAL, "java/lang/Object", "<init>", "()V");
        mv.visitInsn(Opcodes.RETURN);
        // we need this call to take effect ClassWriter.COMPUTE_MAXS flag.
        mv.visitMaxs(0, 0);
        mv.visitEnd();
    }

    {
        MethodVisitor mv;
        mv = cw.visitMethod(Opcodes.ACC_PUBLIC + Opcodes.ACC_STATIC, "main", "([Ljava/lang/String;)V", null,
                null);
        mv.visitCode();
        mv.visitFieldInsn(Opcodes.GETSTATIC, "java/lang/System", "out", "Ljava/io/PrintStream;");
        mv.visitLdcInsn("hello ASM");
        mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/io/PrintStream", "println", "(Ljava/lang/String;)V");
        mv.visitInsn(Opcodes.RETURN);
        // we need this call to take effect ClassWriter.COMPUTE_MAXS flag.
        mv.visitMaxs(0, 0);
        mv.visitEnd();
    }

    cw.visitEnd();

    // build binary
    byte[] bin = cw.toByteArray();

    // save asm trace for human readable
    {
        StringWriter sw = new StringWriter();
        PrintWriter pw = new PrintWriter(sw);
        new ClassReader(bin).accept(new TraceClassVisitor(pw), 0);
        File f = new File(name + ".txt");
        FileUtils.writeStringToFile(f, sw.toString());
    }

    // save as calss file
    {
        File f = new File(name + ".class");
        FileUtils.writeByteArrayToFile(f, bin);
    }

}