xref: /external/annotation-tools/asmx/test/conform/org/objectweb/asm/commons/GASMifierMethodVisitor.java

/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2005 INRIA, France Telecom
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.objectweb.asm.commons;

import org.objectweb.asm.AnnotationVisitor;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Label;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;
import org.objectweb.asm.util.ASMifierAbstractVisitor;
import org.objectweb.asm.util.ASMifierAnnotationVisitor;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * A {@link MethodVisitor} that prints the ASM code that generates the methods
 * it visits.
 *
 * @author Eric Bruneton
 * @author Eugene Kuleshov
 */
public class GASMifierMethodVisitor extends ASMifierAbstractVisitor implements
        MethodVisitor,
        Opcodes
{

    int access;

    Type[] argumentTypes;

    int firstLocal;

    Map locals;

    List localTypes;

    int lastOpcode = -1;

    HashMap labelNames;

    public GASMifierMethodVisitor(int access, String desc) {
        super("mg");
        this.access = access;
        this.labelNames = new HashMap();
        this.argumentTypes = Type.getArgumentTypes(desc);
        int nextLocal = ((Opcodes.ACC_STATIC & access) != 0) ? 0 : 1;
        for (int i = 0; i < argumentTypes.length; i++) {
            nextLocal += argumentTypes[i].getSize();
        }
        this.firstLocal = nextLocal;
        this.locals = new HashMap();
        this.localTypes = new ArrayList();
    }

    public AnnotationVisitor visitAnnotationDefault() {
        buf.setLength(0);
        buf.append("{\n").append("av0 = mg.visitAnnotationDefault();\n");
        text.add(buf.toString());
        ASMifierAnnotationVisitor av = new ASMifierAnnotationVisitor(0);
        text.add(av.getText());
        text.add("}\n");
        return av;
    }

    public AnnotationVisitor visitParameterAnnotation(
        final int parameter,
        final String desc,
        final boolean visible)
    {
        buf.setLength(0);
        buf.append("{\n")
                .append("av0 = mg.visitParameterAnnotation(")
                .append(parameter)
                .append(", \"");
        buf.append(desc);
        buf.append("\", ").append(visible).append(");\n");
        text.add(buf.toString());
        ASMifierAnnotationVisitor av = new ASMifierAnnotationVisitor(0);
        text.add(av.getText());
        text.add("}\n");
        return av;
    }

    public void visitCode() {
        /* text.add("mg.visitCode();\n"); */
    }

    public void visitInsn(final int opcode) {
        buf.setLength(0);
        switch (opcode) {
            case IRETURN:
            case LRETURN:
            case FRETURN:
            case DRETURN:
            case ARETURN:
            case RETURN:
                buf.append("mg.returnValue();\n");
                break;
            case NOP:
                break;
            case ACONST_NULL:
                buf.append("mg.push((String)null);\n");
                break;
            case ICONST_M1:
            case ICONST_0:
            case ICONST_1:
            case ICONST_2:
            case ICONST_3:
            case ICONST_4:
            case ICONST_5:
                buf.append("mg.push(").append(opcode - ICONST_0).append(");\n");
                break;
            case LCONST_0:
            case LCONST_1:
                buf.append("mg.push(")
                        .append(opcode - LCONST_0)
                        .append("L);\n");
                break;
            case FCONST_0:
            case FCONST_1:
            case FCONST_2:
                buf.append("mg.push(")
                        .append(opcode - FCONST_0)
                        .append("f);\n");
                break;
            case DCONST_0:
            case DCONST_1:
                buf.append("mg.push(")
                        .append(opcode - DCONST_0)
                        .append("d);\n");
                break;
            case POP:
                buf.append("mg.pop();\n");
                break;
            case POP2:
                buf.append("mg.pop2();\n");
                break;
            case DUP:
                buf.append("mg.dup();\n");
                break;
            case DUP_X1:
                buf.append("mg.dupX1();\n");
                break;
            case DUP_X2:
                buf.append("mg.dupX2();\n");
                break;
            case DUP2:
                buf.append("mg.dup2();\n");
                break;
            case DUP2_X1:
                buf.append("mg.dup2X1();\n");
                break;
            case DUP2_X2:
                buf.append("mg.dup2X2();\n");
                break;
            case SWAP:
                buf.append("mg.swap();\n");
                break;
            case MONITORENTER:
                buf.append("mg.monitorEnter();\n");
                break;
            case MONITOREXIT:
                buf.append("mg.monitorExit();\n");
                break;
            case ARRAYLENGTH:
                buf.append("mg.arrayLength();\n");
                break;
            case IALOAD:
                buf.append("mg.arrayLoad(Type.INT_TYPE);\n");
                break;
            case LALOAD:
                buf.append("mg.arrayLoad(Type.LONG_TYPE);\n");
                break;
            case FALOAD:
                buf.append("mg.arrayLoad(Type.FLOAT_TYPE);\n");
                break;
            case DALOAD:
                buf.append("mg.arrayLoad(Type.DOUBLE_TYPE);\n");
                break;
            case AALOAD:
                buf.append("mg.arrayLoad(" + getType("java/lang/Object")
                        + ");\n");
                break;
            case BALOAD:
                buf.append("mg.arrayLoad(Type.BYTE_TYPE);\n");
                break;
            case CALOAD:
                buf.append("mg.arrayLoad(Type.CHAR_TYPE);\n");
                break;
            case SALOAD:
                buf.append("mg.arrayLoad(Type.SHORT_TYPE);\n");
                break;
            case IASTORE:
                buf.append("mg.arrayStore(Type.INT_TYPE);\n");
                break;
            case LASTORE:
                buf.append("mg.arrayStore(Type.LONG_TYPE);\n");
                break;
            case FASTORE:
                buf.append("mg.arrayStore(Type.FLOAT_TYPE);\n");
                break;
            case DASTORE:
                buf.append("mg.arrayStore(Type.DOUBLE_TYPE);\n");
                break;
            case AASTORE:
                buf.append("mg.arrayStore(" + getType("java/lang/Object")
                        + ");\n");
                break;
            case BASTORE:
                buf.append("mg.arrayStore(Type.BYTE_TYPE);\n");
                break;
            case CASTORE:
                buf.append("mg.arrayStore(Type.CHAR_TYPE);\n");
                break;
            case SASTORE:
                buf.append("mg.arrayStore(Type.SHORT_TYPE);\n");
                break;
            case IADD:
                buf.append("mg.math(GeneratorAdapter.ADD, Type.INT_TYPE);\n");
                break;
            case LADD:
                buf.append("mg.math(GeneratorAdapter.ADD, Type.LONG_TYPE);\n");
                break;
            case FADD:
                buf.append("mg.math(GeneratorAdapter.ADD, Type.FLOAT_TYPE);\n");
                break;
            case DADD:
                buf.append("mg.math(GeneratorAdapter.ADD, Type.DOUBLE_TYPE);\n");
                break;
            case ISUB:
                buf.append("mg.math(GeneratorAdapter.SUB, Type.INT_TYPE);\n");
                break;
            case LSUB:
                buf.append("mg.math(GeneratorAdapter.SUB, Type.LONG_TYPE);\n");
                break;
            case FSUB:
                buf.append("mg.math(GeneratorAdapter.SUB, Type.FLOAT_TYPE);\n");
                break;
            case DSUB:
                buf.append("mg.math(GeneratorAdapter.SUB, Type.DOUBLE_TYPE);\n");
                break;
            case IMUL:
                buf.append("mg.math(GeneratorAdapter.MUL, Type.INT_TYPE);\n");
                break;
            case LMUL:
                buf.append("mg.math(GeneratorAdapter.MUL, Type.LONG_TYPE);\n");
                break;
            case FMUL:
                buf.append("mg.math(GeneratorAdapter.MUL, Type.FLOAT_TYPE);\n");
                break;
            case DMUL:
                buf.append("mg.math(GeneratorAdapter.MUL, Type.DOUBLE_TYPE);\n");
                break;
            case IDIV:
                buf.append("mg.math(GeneratorAdapter.DIV, Type.INT_TYPE);\n");
                break;
            case LDIV:
                buf.append("mg.math(GeneratorAdapter.DIV, Type.LONG_TYPE);\n");
                break;
            case FDIV:
                buf.append("mg.math(GeneratorAdapter.DIV, Type.FLOAT_TYPE);\n");
                break;
            case DDIV:
                buf.append("mg.math(GeneratorAdapter.DIV, Type.DOUBLE_TYPE);\n");
                break;
            case IREM:
                buf.append("mg.math(GeneratorAdapter.REM, Type.INT_TYPE);\n");
                break;
            case LREM:
                buf.append("mg.math(GeneratorAdapter.REM, Type.LONG_TYPE);\n");
                break;
            case FREM:
                buf.append("mg.math(GeneratorAdapter.REM, Type.FLOAT_TYPE);\n");
                break;
            case DREM:
                buf.append("mg.math(GeneratorAdapter.REM, Type.DOUBLE_TYPE);\n");
                break;
            case INEG:
                buf.append("mg.math(GeneratorAdapter.NEG, Type.INT_TYPE);\n");
                break;
            case LNEG:
                buf.append("mg.math(GeneratorAdapter.NEG, Type.LONG_TYPE);\n");
                break;
            case FNEG:
                buf.append("mg.math(GeneratorAdapter.NEG, Type.FLOAT_TYPE);\n");
                break;
            case DNEG:
                buf.append("mg.math(GeneratorAdapter.NEG, Type.DOUBLE_TYPE);\n");
                break;
            case ISHL:
                buf.append("mg.math(GeneratorAdapter.SHL, Type.INT_TYPE);\n");
                break;
            case LSHL:
                buf.append("mg.math(GeneratorAdapter.SHL, Type.LONG_TYPE);\n");
                break;
            case ISHR:
                buf.append("mg.math(GeneratorAdapter.SHR, Type.INT_TYPE);\n");
                break;
            case LSHR:
                buf.append("mg.math(GeneratorAdapter.SHR, Type.LONG_TYPE);\n");
                break;
            case IUSHR:
                buf.append("mg.math(GeneratorAdapter.USHR, Type.INT_TYPE);\n");
                break;
            case LUSHR:
                buf.append("mg.math(GeneratorAdapter.USHR, Type.LONG_TYPE);\n");
                break;
            case IAND:
                buf.append("mg.math(GeneratorAdapter.AND, Type.INT_TYPE);\n");
                break;
            case LAND:
                buf.append("mg.math(GeneratorAdapter.AND, Type.LONG_TYPE);\n");
                break;
            case IOR:
                buf.append("mg.math(GeneratorAdapter.OR, Type.INT_TYPE);\n");
                break;
            case LOR:
                buf.append("mg.math(GeneratorAdapter.OR, Type.LONG_TYPE);\n");
                break;
            case IXOR:
                buf.append("mg.math(GeneratorAdapter.XOR, Type.INT_TYPE);\n");
                break;
            case LXOR:
                buf.append("mg.math(GeneratorAdapter.XOR, Type.LONG_TYPE);\n");
                break;
            case ATHROW:
                buf.append("mg.throwException();\n");
                break;
            case I2L:
                buf.append("mg.cast(Type.INT_TYPE, Type.LONG_TYPE);\n");
                break;
            case I2F:
                buf.append("mg.cast(Type.INT_TYPE, Type.FLOAT_TYPE);\n");
                break;
            case I2D:
                buf.append("mg.cast(Type.INT_TYPE, Type.DOUBLE_TYPE);\n");
                break;
            case L2I:
                buf.append("mg.cast(Type.LONG_TYPE, Type.INT_TYPE);\n");
                break;
            case L2F:
                buf.append("mg.cast(Type.LONG_TYPE, Type.FLOAT_TYPE);\n");
                break;
            case L2D:
                buf.append("mg.cast(Type.LONG_TYPE, Type.DOUBLE_TYPE);\n");
                break;
            case F2I:
                buf.append("mg.cast(Type.FLOAT_TYPE, Type.INT_TYPE);\n");
                break;
            case F2L:
                buf.append("mg.cast(Type.FLOAT_TYPE, Type.LONG_TYPE);\n");
                break;
            case F2D:
                buf.append("mg.cast(Type.FLOAT_TYPE, Type.DOUBLE_TYPE);\n");
                break;
            case D2I:
                buf.append("mg.cast(Type.DOUBLE_TYPE, Type.INT_TYPE);\n");
                break;
            case D2L:
                buf.append("mg.cast(Type.DOUBLE_TYPE, Type.LONG_TYPE);\n");
                break;
            case D2F:
                buf.append("mg.cast(Type.DOUBLE_TYPE, Type.FLOAT_TYPE);\n");
                break;
            case I2B:
                // TODO detect if previous element in 'text' is a cast,
                // for possible optimisations (e.g. cast(F,I) cast(I,B) =
                // cast(F,B))
                buf.append("mg.cast(Type.INT_TYPE, Type.BYTE_TYPE);\n");
                break;
            case I2C: // idem
                buf.append("mg.cast(Type.INT_TYPE, Type.CHAR_TYPE);\n");
                break;
            case I2S: // idem
                buf.append("mg.cast(Type.INT_TYPE, Type.SHORT_TYPE);\n");
                break;
            case LCMP:
            case FCMPL:
            case FCMPG:
            case DCMPL:
            case DCMPG:
                // TODO detect xCMPy IF_ICMP -> ifCmp(..., ..., label)
                buf.append("mg.visitInsn(")
                        .append(OPCODES[opcode])
                        .append(");\n");
                break;
            default:
                throw new RuntimeException("unexpected case");
        }
        text.add(buf.toString());
        lastOpcode = opcode;
    }

    public void visitIntInsn(final int opcode, final int operand) {
        buf.setLength(0);
        if (opcode == NEWARRAY) {
            String type;
            switch (operand) {
                case T_BOOLEAN:
                    type = "Type.BOOLEAN_TYPE";
                    break;
                case T_CHAR:
                    type = "Type.CHAR_TYPE";
                    break;
                case T_FLOAT:
                    type = "Type.FLOAT_TYPE";
                    break;
                case T_DOUBLE:
                    type = "Type.DOUBLE_TYPE";
                    break;
                case T_BYTE:
                    type = "Type.BYTE_TYPE";
                    break;
                case T_SHORT:
                    type = "Type.SHORT_TYPE";
                    break;
                case T_INT:
                    type = "Type.INT_TYPE";
                    break;
                case T_LONG:
                    type = "Type.LONG_TYPE";
                    break;
                default:
                    throw new RuntimeException("unexpected case");
            }
            buf.append("mg.newArray(").append(type).append(");\n");
        } else {
            buf.append("mg.push(").append(operand).append(");\n");
        }
        text.add(buf.toString());
        lastOpcode = opcode;
    }

    public void visitVarInsn(final int opcode, int var) {
        buf.setLength(0);
        switch (opcode) {
            case RET:
                buf.append("mg.ret(");
                if (var < firstLocal) {
                    buf.append(var);
                } else {
                    int v = generateNewLocal(var, "Type.INT_TYPE");
                    buf.append("local").append(v);
                }
                buf.append(");\n");
                break;

            case ILOAD:
                generateLoadLocal(var, "Type.INT_TYPE");
                break;
            case LLOAD:
                generateLoadLocal(var, "Type.LONG_TYPE");
                break;
            case FLOAD:
                generateLoadLocal(var, "Type.FLOAT_TYPE");
                break;
            case DLOAD:
                generateLoadLocal(var, "Type.DOUBLE_TYPE");
                break;
            case ALOAD:
                generateLoadLocal(var, getType("java/lang/Object"));
                break;

            case ISTORE:
                generateStoreLocal(var, "Type.INT_TYPE");
                break;
            case LSTORE:
                generateStoreLocal(var, "Type.LONG_TYPE");
                break;
            case FSTORE:
                generateStoreLocal(var, "Type.FLOAT_TYPE");
                break;
            case DSTORE:
                generateStoreLocal(var, "Type.DOUBLE_TYPE");
                break;
            case ASTORE:
                generateStoreLocal(var, getType("java/lang/Object"));
                break;

            default:
                throw new RuntimeException("unexpected case");
        }

        text.add(buf.toString());
        lastOpcode = opcode;
    }

    private void generateLoadLocal(int var, String type) {
        if (var < firstLocal) {
            if (var == 0 && (access & ACC_STATIC) == 0) {
                buf.append("mg.loadThis();\n");
            } else {
                buf.append("mg.loadArg(")
                        .append(getArgIndex(var))
                        .append(");\n");
            }
        } else {
            int local = generateNewLocal(var, type);
            buf.append("mg.loadLocal(local").append(local);
            if (!type.equals(localTypes.get(local))) {
                localTypes.set(local, type);
                buf.append(", ").append(type);
            }
            buf.append(");\n");
        }
    }

    private void generateStoreLocal(int var, String type) {
        if (var < firstLocal) {
            buf.append("mg.storeArg(").append(getArgIndex(var)).append(");\n");
        } else {
            int local = generateNewLocal(var, type);
            buf.append("mg.storeLocal(local").append(local);
            if (!type.equals(localTypes.get(local))) {
                localTypes.set(local, type);
                buf.append(", ").append(type);
            }
            buf.append(");\n");
        }
    }

    private int generateNewLocal(int var, String type) {
        Integer i = (Integer) locals.get(new Integer(var));
        if (i == null) {
            int local = locals.size();
            locals.put(new Integer(var), new Integer(local));
            localTypes.add(type);
            buf.append("int local" + local + " = mg.newLocal(" + type + ");\n");
            return local;
        }
        return i.intValue();
    }

    private int getArgIndex(int var) {
        int nextLocal = ((Opcodes.ACC_STATIC & access) != 0) ? 0 : 1;
        int i = 0;
        while (nextLocal != var) {
            nextLocal += argumentTypes[i++].getSize();
        }
        return i;
    }

    public void visitTypeInsn(final int opcode, final String desc) {
        String type;
        if (desc.charAt(0) == '[') {
            type = getDescType(desc);
        } else {
            type = getType(desc);
        }
        buf.setLength(0);
        if (opcode == NEW) {
            buf.append("mg.newInstance(").append(type).append(");\n");
        } else if (opcode == ANEWARRAY) {
            buf.append("mg.newArray(").append(type).append(");\n");
        } else if (opcode == CHECKCAST) {
            buf.append("mg.checkCast(").append(type).append(");\n");
        } else if (opcode == INSTANCEOF) {
            buf.append("mg.instanceOf(").append(type).append(");\n");
        }
        text.add(buf.toString());
        lastOpcode = opcode;
    }

    public void visitFieldInsn(
        final int opcode,
        final String owner,
        final String name,
        final String desc)
    {
        buf.setLength(0);
        switch (opcode) {
            case GETFIELD:
                buf.append("mg.getField(");
                break;
            case PUTFIELD:
                buf.append("mg.putField(");
                break;
            case GETSTATIC:
                buf.append("mg.getStatic(");
                break;
            case PUTSTATIC:
                buf.append("mg.putStatic(");
                break;
            default:
                throw new RuntimeException("unexpected case");
        }
        buf.append(getType(owner));
        buf.append(", \"");
        buf.append(name);
        buf.append("\", ");
        buf.append(getDescType(desc));
        buf.append(");\n");
        text.add(buf.toString());
        lastOpcode = opcode;
    }

    public void visitMethodInsn(
        final int opcode,
        final String owner,
        final String name,
        final String desc)
    {
        buf.setLength(0);
        switch (opcode) {
            case INVOKEVIRTUAL:
                buf.append("mg.invokeVirtual(");
                break;
            case INVOKESPECIAL:
                buf.append("mg.invokeConstructor(");
                break;
            case INVOKESTATIC:
                buf.append("mg.invokeStatic(");
                break;
            case INVOKEINTERFACE:
                buf.append("mg.invokeInterface(");
                break;
            default:
                throw new RuntimeException("unexpected case");
        }
        if (owner.charAt(0) == '[') {
            buf.append(getDescType(owner));
        } else {
            buf.append(getType(owner));
        }
        buf.append(", ");
        buf.append(getMethod(name, desc));
        buf.append(");\n");
        text.add(buf.toString());
        lastOpcode = opcode;
    }

    public void visitJumpInsn(final int opcode, final Label label) {
        buf.setLength(0);
        declareLabel(label);
        if (opcode == GOTO || opcode == IFNULL || opcode == IFNONNULL) {
            if (opcode == GOTO)
                buf.append("mg.goTo(");
            if (opcode == IFNULL)
                buf.append("mg.ifNull(");
            if (opcode == IFNONNULL)
                buf.append("mg.ifNonNull(");
            appendLabel(label);
            buf.append(");\n");
        } else if (opcode == IF_ICMPEQ) {
            buf.append("mg.ifICmp(GeneratorAdapter.EQ, ");
            appendLabel(label);
            buf.append(");\n");
        } else if (opcode == IF_ICMPNE) {
            buf.append("mg.ifICmp(GeneratorAdapter.NE, ");
            appendLabel(label);
            buf.append(");\n");
        } else if (opcode == IF_ICMPLT) {
            buf.append("mg.ifICmp(GeneratorAdapter.LT, ");
            appendLabel(label);
            buf.append(");\n");
        } else if (opcode == IF_ICMPGE) {
            buf.append("mg.ifICmp(GeneratorAdapter.GE, ");
            appendLabel(label);
            buf.append(");\n");
        } else if (opcode == IF_ICMPGT) {
            buf.append("mg.ifICmp(GeneratorAdapter.GT, ");
            appendLabel(label);
            buf.append(");\n");
        } else if (opcode == IF_ICMPLE) {
            buf.append("mg.ifICmp(GeneratorAdapter.LE, ");
            appendLabel(label);
            buf.append(");\n");
        } else if (opcode == IF_ACMPEQ) {
            buf.append("mg.ifCmp(");
            buf.append(getType("java/lang/Object"))
                    .append(", ")
                    .append("GeneratorAdapter.EQ, ");
            appendLabel(label);
            buf.append(");\n");
        } else if (opcode == IF_ACMPNE) {
            buf.append("mg.ifCmp(");
            buf.append(getType("java/lang/Object"))
                    .append(", ")
                    .append("GeneratorAdapter.NE, ");
            appendLabel(label);
            buf.append(");\n");
        } else if (opcode == IFEQ) {
            buf.append("mg.ifZCmp(GeneratorAdapter.EQ, ");
            appendLabel(label);
            buf.append(");\n");
        } else if (opcode == IFNE) {
            buf.append("mg.ifZCmp(GeneratorAdapter.NE, ");
            appendLabel(label);
            buf.append(");\n");
        } else if (opcode == IFLT) {
            buf.append("mg.ifZCmp(GeneratorAdapter.LT, ");
            appendLabel(label);
            buf.append(");\n");
        } else if (opcode == IFGE) {
            buf.append("mg.ifZCmp(GeneratorAdapter.GE, ");
            appendLabel(label);
            buf.append(");\n");
        } else if (opcode == IFGT) {
            buf.append("mg.ifZCmp(GeneratorAdapter.GT, ");
            appendLabel(label);
            buf.append(");\n");
        } else if (opcode == IFLE) {
            buf.append("mg.ifZCmp(GeneratorAdapter.LE, ");
            appendLabel(label);
            buf.append(");\n");
        } else {
            buf.append("mg.visitJumpInsn(")
                    .append(OPCODES[opcode])
                    .append(", ");
            appendLabel(label);
            buf.append(");\n");
        }
        text.add(buf.toString());
        lastOpcode = opcode;
    }

    public void visitLabel(final Label label) {
        buf.setLength(0);
        declareLabel(label);
        buf.append("mg.mark(");
        appendLabel(label);
        buf.append(");\n");
        text.add(buf.toString());
        lastOpcode = -1;
    }

    public void visitLdcInsn(final Object cst) {
        buf.setLength(0);
        buf.append("mg.push(");
        if (cst == null) {
            buf.append("(String)null");
        } else if (cst instanceof Long) {
            buf.append(cst + "L");
        } else if (cst instanceof Float) {
            float f = ((Float) cst).floatValue();
            if (Float.isNaN(f)) {
                buf.append("Float.NaN");
            } else if (Float.isInfinite(f)) {
                buf.append(f > 0
                        ? "Float.POSITIVE_INFINITY"
                        : "Float.NEGATIVE_INFINITY");
            } else {
                buf.append(cst + "f");
            }
        } else if (cst instanceof Double) {
            double d = ((Double) cst).doubleValue();
            if (Double.isNaN(d)) {
                buf.append("Double.NaN");
            } else if (Double.isInfinite(d)) {
                buf.append(d > 0
                        ? "Double.POSITIVE_INFINITY"
                        : "Double.NEGATIVE_INFINITY");
            } else {
                buf.append(cst + "d");
            }
        } else if (cst instanceof String) {
            appendString(buf, (String) cst);
        } else if (cst instanceof Type) {
            buf.append("Type.getType(\"").append(cst).append("\")");
        } else {
            buf.append(cst);
        }
        buf.append(");\n");
        text.add(buf.toString());
        lastOpcode = LDC;
    }

    public void visitIincInsn(final int var, final int increment) {
        buf.setLength(0);
        if (var < firstLocal) {
            buf.append("mg.iinc(").append(var);
        } else {
            int v = generateNewLocal(var, "Type.INT_TYPE");
            buf.append("mg.iinc(local").append(v);
        }
        buf.append(", ").append(increment).append(");\n");
        text.add(buf.toString());
        lastOpcode = IINC;
    }

    public void visitTableSwitchInsn(
        final int min,
        final int max,
        final Label dflt,
        final Label labels[])
    {
        buf.setLength(0);
        for (int i = 0; i < labels.length; ++i) {
            declareLabel(labels[i]);
        }
        declareLabel(dflt);

        buf.append("mg.visitTableSwitchInsn(")
                .append(min)
                .append(", ")
                .append(max)
                .append(", ");
        appendLabel(dflt);
        buf.append(", new Label[] {");
        for (int i = 0; i < labels.length; ++i) {
            buf.append(i == 0 ? " " : ", ");
            appendLabel(labels[i]);
        }
        buf.append(" }); // TODO\n");
        text.add(buf.toString());
        lastOpcode = TABLESWITCH;
    }

    public void visitLookupSwitchInsn(
        final Label dflt,
        final int keys[],
        final Label labels[])
    {
        buf.setLength(0);
        for (int i = 0; i < labels.length; ++i) {
            declareLabel(labels[i]);
        }
        declareLabel(dflt);

        buf.append("mg.visitLookupSwitchInsn(");
        appendLabel(dflt);
        buf.append(", new int[] {");
        for (int i = 0; i < keys.length; ++i) {
            buf.append(i == 0 ? " " : ", ").append(keys[i]);
        }
        buf.append(" }, new Label[] {");
        for (int i = 0; i < labels.length; ++i) {
            buf.append(i == 0 ? " " : ", ");
            appendLabel(labels[i]);
        }
        buf.append(" }); // TODO\n");
        text.add(buf.toString());
        lastOpcode = LOOKUPSWITCH;
    }

    public void visitMultiANewArrayInsn(final String desc, final int dims) {
        buf.setLength(0);
        buf.append("mg.visitMultiANewArrayInsn(\"");
        buf.append(desc);
        buf.append("\", ").append(dims).append(");\n");
        text.add(buf.toString());
        lastOpcode = MULTIANEWARRAY;
    }

    public void visitTryCatchBlock(
        final Label start,
        final Label end,
        final Label handler,
        final String type)
    {
        buf.setLength(0);
        declareLabel(start);
        declareLabel(end);
        declareLabel(handler);
        buf.append("mg.visitTryCatchBlock(");
        appendLabel(start);
        buf.append(", ");
        appendLabel(end);
        buf.append(", ");
        appendLabel(handler);
        buf.append(", ");
        if (type == null) {
            buf.append("null");
        } else {
            buf.append('"').append(type).append('"');
        }
        buf.append("); // TODO\n");
        text.add(buf.toString());
        lastOpcode = -1;
    }

    public void visitLocalVariable(
        final String name,
        final String desc,
        final String signature,
        final Label start,
        final Label end,
        final int index)
    {
        buf.setLength(0);
        buf.append("mg.visitLocalVariable(\"");
        buf.append(name);
        buf.append("\", \"");
        buf.append(desc);
        buf.append("\", ");
        if (signature == null) {
            buf.append("null");
        } else {
            buf.append('"').append(signature).append('"');
        }
        buf.append(", ");
        appendLabel(start);
        buf.append(", ");
        appendLabel(end);
        buf.append(", ").append(index).append(");\n");
        text.add(buf.toString());
        lastOpcode = -1;
    }

    public void visitLineNumber(final int line, final Label start) {
        buf.setLength(0);
        buf.append("mg.visitLineNumber(").append(line).append(", ");
        appendLabel(start);
        buf.append(");\n");
        text.add(buf.toString());
        lastOpcode = -1;
    }

    public void visitMaxs(final int maxStack, final int maxLocals) {
        text.add("mg.endMethod();\n");
        lastOpcode = -1;
    }

    public void visitEnd() {
        // does nothing
    }

    static String getType(String internalName) {
        return "Type.getType(\"L" + internalName + ";\")";
    }

    static String getDescType(String desc) {
        if (desc.equals("Z"))
            return "Type.BOOLEAN_TYPE";
        if (desc.equals("B"))
            return "Type.BYTE_TYPE";
        if (desc.equals("C"))
            return "Type.CHAR_TYPE";
        if (desc.equals("D"))
            return "Type.DOUBLE_TYPE";
        if (desc.equals("F"))
            return "Type.FLOAT_TYPE";
        if (desc.equals("I"))
            return "Type.INT_TYPE";
        if (desc.equals("J"))
            return "Type.LONG_TYPE";
        if (desc.equals("S"))
            return "Type.SHORT_TYPE";
        if (desc.equals("V"))
            return "Type.VOID_TYPE";
        return "Type.getType(\"" + desc + "\")";
    }

    static String getMethod(String name, String desc) {
        Type rt = Type.getReturnType(desc);
        Type[] argt = Type.getArgumentTypes(desc);
        StringBuffer buf = new StringBuffer();
        buf.append("Method.getMethod(\"");
        buf.append(rt.getClassName()).append(" ");
        buf.append(name).append("(");
        for (int i = 0; i < argt.length; ++i) {
            if (i > 0)
                buf.append(',');
            buf.append(argt[i].getClassName());
        }
        buf.append(")\")");
        return buf.toString();
    }

    /**
     * Appends a declaration of the given label to {@link #buf buf}. This
     * declaration is of the form "Label lXXX = new Label();". Does nothing if
     * the given label has already been declared.
     *
     * @param l a label.
     */
    private void declareLabel(final Label l) {
        String name = (String) labelNames.get(l);
        if (name == null) {
            name = "label" + labelNames.size();
            labelNames.put(l, name);
            buf.append("Label ").append(name).append(" = mg.newLabel();\n");
        }
    }

    /**
     * Appends the name of the given label to {@link #buf buf}. The given label
     * <i>must</i> already have a name. One way to ensure this is to always
     * call {@link #declareLabel declared} before calling this method.
     *
     * @param l a label.
     */
    private void appendLabel(final Label l) {
        buf.append((String) labelNames.get(l));
    }
}