    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one
    003 * or more contributor license agreements.  See the NOTICE file
    004 * distributed with this work for additional information
    005 * regarding copyright ownership.  The ASF licenses this file
    006 * to you under the Apache License, Version 2.0 (the
    007 * "License"); you may not use this file except in compliance
    008 * with the License.  You may obtain a copy of the License at
    009 *
    010 *   https://www.apache.org/licenses/LICENSE-2.0
    011 *
    012 * Unless required by applicable law or agreed to in writing,
    013 * software distributed under the License is distributed on an
    014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    015 * KIND, either express or implied.  See the License for the
    016 * specific language governing permissions and limitations
    017 * under the License.
    018 */
    019package org.apache.bcel.verifier.statics;
    020
    021import java.util.HashMap;
    022import java.util.HashSet;
    023import java.util.Map;
    024import java.util.Objects;
    025import java.util.Set;
    026
    027import org.apache.bcel.Const;
    028import org.apache.bcel.Constants;
    029import org.apache.bcel.Repository;
    030import org.apache.bcel.classfile.Attribute;
    031import org.apache.bcel.classfile.ClassFormatException;
    032import org.apache.bcel.classfile.Code;
    033import org.apache.bcel.classfile.CodeException;
    034import org.apache.bcel.classfile.Constant;
    035import org.apache.bcel.classfile.ConstantClass;
    036import org.apache.bcel.classfile.ConstantDouble;
    037import org.apache.bcel.classfile.ConstantFieldref;
    038import org.apache.bcel.classfile.ConstantFloat;
    039import org.apache.bcel.classfile.ConstantInteger;
    040import org.apache.bcel.classfile.ConstantInterfaceMethodref;
    041import org.apache.bcel.classfile.ConstantLong;
    042import org.apache.bcel.classfile.ConstantMethodref;
    043import org.apache.bcel.classfile.ConstantNameAndType;
    044import org.apache.bcel.classfile.ConstantPool;
    045import org.apache.bcel.classfile.ConstantString;
    046import org.apache.bcel.classfile.ConstantUtf8;
    047import org.apache.bcel.classfile.ConstantValue;
    048import org.apache.bcel.classfile.Deprecated;
    049import org.apache.bcel.classfile.DescendingVisitor;
    050import org.apache.bcel.classfile.EmptyVisitor;
    051import org.apache.bcel.classfile.ExceptionTable;
    052import org.apache.bcel.classfile.Field;
    053import org.apache.bcel.classfile.InnerClass;
    054import org.apache.bcel.classfile.InnerClasses;
    055import org.apache.bcel.classfile.JavaClass;
    056import org.apache.bcel.classfile.LineNumber;
    057import org.apache.bcel.classfile.LineNumberTable;
    058import org.apache.bcel.classfile.LocalVariable;
    059import org.apache.bcel.classfile.LocalVariableTable;
    060import org.apache.bcel.classfile.Method;
    061import org.apache.bcel.classfile.Node;
    062import org.apache.bcel.classfile.SourceFile;
    063import org.apache.bcel.classfile.Synthetic;
    064import org.apache.bcel.classfile.Unknown;
    065import org.apache.bcel.classfile.Utility;
    066import org.apache.bcel.generic.ArrayType;
    067import org.apache.bcel.generic.ObjectType;
    068import org.apache.bcel.generic.Type;
    069import org.apache.bcel.verifier.PassVerifier;
    070import org.apache.bcel.verifier.VerificationResult;
    071import org.apache.bcel.verifier.Verifier;
    072import org.apache.bcel.verifier.VerifierFactory;
    073import org.apache.bcel.verifier.exc.AssertionViolatedException;
    074import org.apache.bcel.verifier.exc.ClassConstraintException;
    075import org.apache.bcel.verifier.exc.LocalVariableInfoInconsistentException;
    076import org.apache.commons.lang3.StringUtils;
    077
    078/**
    079 * This PassVerifier verifies a class file according to pass 2 as described in The Java Virtual Machine Specification,
    080 * 2nd edition. More detailed information is to be found at the do_verify() method's documentation.
    081 *
    082 * @see #do_verify()
    083 */
    084public final class Pass2Verifier extends PassVerifier implements Constants {
    085
    086    /**
    087     * A Visitor class that ensures the constant pool satisfies the static constraints. The visitXXX() methods throw
    088     * ClassConstraintException instances otherwise.
    089     *
    090     * @see #constantPoolEntriesSatisfyStaticConstraints()
    091     */
    092    private final class CPESSC_Visitor extends EmptyVisitor {
    093        private final Class<?> CONST_Class;
    094
    095        /*
    096         * private Class<?> CONST_Fieldref; private Class<?> CONST_Methodref; private Class<?> CONST_InterfaceMethodref;
    097         */
    098        private final Class<?> CONST_String;
    099        private final Class<?> CONST_Integer;
    100        private final Class<?> CONST_Float;
    101        private final Class<?> CONST_Long;
    102        private final Class<?> CONST_Double;
    103        private final Class<?> CONST_NameAndType;
    104        private final Class<?> CONST_Utf8;
    105
    106        private final JavaClass jc;
    107        private final ConstantPool cp; // ==jc.getConstantPool() -- only here to save typing work and computing power.
    108        private final int cplen; // == cp.getLength() -- to save computing power.
    109        private final DescendingVisitor carrier;
    110
    111        private final Set<String> fieldNames = new HashSet<>();
    112        private final Set<String> fieldNamesAndDesc = new HashSet<>();
    113        private final Set<String> methodNamesAndDesc = new HashSet<>();
    114
    115        private CPESSC_Visitor(final JavaClass jc) {
    116            this.jc = jc;
    117            this.cp = jc.getConstantPool();
    118            this.cplen = cp.getLength();
    119
    120            this.CONST_Class = ConstantClass.class;
    121            /*
    122             * CONST_Fieldref = ConstantFieldref.class; CONST_Methodref = ConstantMethodref.class; CONST_InterfaceMethodref =
    123             * ConstantInterfaceMethodref.class;
    124             */
    125            this.CONST_String = ConstantString.class;
    126            this.CONST_Integer = ConstantInteger.class;
    127            this.CONST_Float = ConstantFloat.class;
    128            this.CONST_Long = ConstantLong.class;
    129            this.CONST_Double = ConstantDouble.class;
    130            this.CONST_NameAndType = ConstantNameAndType.class;
    131            this.CONST_Utf8 = ConstantUtf8.class;
    132
    133            this.carrier = new DescendingVisitor(jc, this);
    134            this.carrier.visit();
    135        }
    136
    137        private void checkIndex(final Node referrer, final int index, final Class<?> shouldbe) {
    138            if (index < 0 || index >= cplen) {
    139                throw new ClassConstraintException("Invalid index '" + index + "' used by '" + tostring(referrer) + "'.");
    140            }
    141            final Constant c = cp.getConstant(index);
    142            if (!shouldbe.isInstance(c)) {
    143                /* String isnot = shouldbe.toString().substring(shouldbe.toString().lastIndexOf(".")+1); //Cut all before last "." */
    144                throw new ClassConstraintException(
    145                    "Illegal constant '" + tostring(c) + "' at index '" + index + "'. '" + tostring(referrer) + "' expects a '" + shouldbe + "'.");
    146            }
    147        }
    148
    149        // SYNTHETIC: see above
    150        // DEPRECATED: see above
    151        /////////////////////////////////////////////////////////
    152        // method_info-structure-ATTRIBUTES (vmspec2 4.6, 4.7) //
    153        /////////////////////////////////////////////////////////
    154        @Override
    155        public void visitCode(final Code obj) { // vmspec2 4.7.3
    156            try {
    157                // No code attribute allowed for native or abstract methods: see visitMethod(Method).
    158                // Code array constraints are checked in Pass3 (3a and 3b).
    159
    160                checkIndex(obj, obj.getNameIndex(), CONST_Utf8);
    161
    162                final String name = ((ConstantUtf8) cp.getConstant(obj.getNameIndex())).getBytes();
    163                if (!name.equals("Code")) {
    164                    throw new ClassConstraintException("The Code attribute '" + tostring(obj) + "' is not correctly named 'Code' but '" + name + "'.");
    165                }
    166
    167                if (!(carrier.predecessor() instanceof Method)) {
    168                    addMessage("Code attribute '" + tostring(obj) + "' is not declared in a method_info structure but in '" + carrier.predecessor()
    169                            + "'. Ignored.");
    170                    return;
    171                }
    172                final Method m = (Method) carrier.predecessor(); // we can assume this method was visited before;
    173                                                                 // for example the data consistency was verified.
    174
    175                if (obj.getCode().length == 0) {
    176                    throw new ClassConstraintException("Code array of Code attribute '" + tostring(obj) + "' (method '" + m + "') must not be empty.");
    177                }
    178
    179                // In JustIce, the check for correct offsets into the code array is delayed to Pass 3a.
    180                final CodeException[] excTable = obj.getExceptionTable();
    181                for (final CodeException element : excTable) {
    182                    final int excIndex = element.getCatchType();
    183                    if (excIndex != 0) { // if 0, it catches all Throwables
    184                        checkIndex(obj, excIndex, CONST_Class);
    185                        final ConstantClass cc = (ConstantClass) cp.getConstant(excIndex);
    186                        // cannot be sure this ConstantClass has already been visited (checked)!
    187                        checkIndex(cc, cc.getNameIndex(), CONST_Utf8);
    188                        final String cname = Utility.pathToPackage(((ConstantUtf8) cp.getConstant(cc.getNameIndex())).getBytes());
    189
    190                        Verifier v = VerifierFactory.getVerifier(cname);
    191                        VerificationResult vr = v.doPass1();
    192
    193                        if (vr != VerificationResult.VR_OK) {
    194                            throw new ClassConstraintException("Code attribute '" + tostring(obj) + "' (method '" + m + "') has an exception_table entry '"
    195                                    + tostring(element) + "' that references '" + cname + "' as an Exception but it does not pass verification pass 1: " + vr);
    196                        }
    197                        // We cannot safely trust any other "instanceof" mechanism. We need to transitively verify
    198                        // the ancestor hierarchy.
    199                        JavaClass e = Repository.lookupClass(cname);
    200                        final JavaClass t = Repository.lookupClass(Type.THROWABLE.getClassName());
    201                        final JavaClass o = Repository.lookupClass(Type.OBJECT.getClassName());
    202                        while (e != o) {
    203                            if (e == t) {
    204                                break; // It's a subclass of Throwable, OKAY, leave.
    205                            }
    206
    207                            v = VerifierFactory.getVerifier(e.getSuperclassName());
    208                            vr = v.doPass1();
    209                            if (vr != VerificationResult.VR_OK) {
    210                                throw new ClassConstraintException("Code attribute '" + tostring(obj) + "' (method '" + m + "') has an exception_table entry '"
    211                                        + tostring(element) + "' that references '" + cname + "' as an Exception but '" + e.getSuperclassName()
    212                                        + "' in the ancestor hierachy does not pass verification pass 1: " + vr);
    213                            }
    214                            e = Repository.lookupClass(e.getSuperclassName());
    215                        }
    216                        if (e != t) {
    217                            throw new ClassConstraintException(
    218                                    "Code attribute '" + tostring(obj) + "' (method '" + m + "') has an exception_table entry '" + tostring(element)
    219                                            + "' that references '" + cname + "' as an Exception but it is not a subclass of '" + t.getClassName() + "'.");
    220                        }
    221                    }
    222                }
    223
    224                // Create object for local variables information
    225                // This is highly unelegant due to usage of the Visitor pattern.
    226                // TODO: rework it.
    227                int methodNumber = -1;
    228                final Method[] ms = Repository.lookupClass(verifier.getClassName()).getMethods();
    229                for (int mn = 0; mn < ms.length; mn++) {
    230                    if (m == ms[mn]) {
    231                        methodNumber = mn;
    232                        break;
    233                    }
    234                }
    235                // If the .class file is malformed the loop above may not find a method.
    236                // Try matching names instead of pointers.
    237                if (methodNumber < 0) {
    238                    for (int mn = 0; mn < ms.length; mn++) {
    239                        if (m.getName().equals(ms[mn].getName())) {
    240                            methodNumber = mn;
    241                            break;
    242                        }
    243                    }
    244                }
    245
    246                if (methodNumber < 0) { // Mmmmh. Can we be sure BCEL does not sometimes instantiate new objects?
    247                    throw new AssertionViolatedException("Could not find a known BCEL Method object in the corresponding BCEL JavaClass object.");
    248                }
    249                localVariablesInfos[methodNumber] = new LocalVariablesInfo(obj.getMaxLocals());
    250
    251                int numOfLvtAttribs = 0;
    252                // Now iterate through the attributes the Code attribute has.
    253                final Attribute[] atts = obj.getAttributes();
    254                for (final Attribute att : atts) {
    255                    if (!(att instanceof LineNumberTable) && !(att instanceof LocalVariableTable)) {
    256                        addMessage("Attribute '" + tostring(att) + "' as an attribute of Code attribute '" + tostring(obj) + "' (method '" + m
    257                                + "') is unknown and will therefore be ignored.");
    258                    } else { // LineNumberTable or LocalVariableTable
    259                        addMessage("Attribute '" + tostring(att) + "' as an attribute of Code attribute '" + tostring(obj) + "' (method '" + m
    260                                + "') will effectively be ignored and is only useful for debuggers and such.");
    261                    }
    262
    263                    // LocalVariableTable check (partially delayed to Pass3a).
    264                    // Here because its easier to collect the information of the
    265                    // (possibly more than one) LocalVariableTables belonging to
    266                    // one certain Code attribute.
    267                    if (att instanceof LocalVariableTable) { // checks conforming to vmspec2 4.7.9
    268
    269                        final LocalVariableTable lvt = (LocalVariableTable) att;
    270
    271                        checkIndex(lvt, lvt.getNameIndex(), CONST_Utf8);
    272
    273                        final String lvtname = ((ConstantUtf8) cp.getConstant(lvt.getNameIndex())).getBytes();
    274                        if (!lvtname.equals("LocalVariableTable")) {
    275                            throw new ClassConstraintException("The LocalVariableTable attribute '" + tostring(lvt)
    276                                    + "' is not correctly named 'LocalVariableTable' but '" + lvtname + "'.");
    277                        }
    278
    279                        // In JustIce, the check for correct offsets into the code array is delayed to Pass 3a.
    280                        for (final LocalVariable localvariable : lvt.getLocalVariableTable()) {
    281                            checkIndex(lvt, localvariable.getNameIndex(), CONST_Utf8);
    282                            final String localname = ((ConstantUtf8) cp.getConstant(localvariable.getNameIndex())).getBytes();
    283                            if (!validJavaIdentifier(localname)) {
    284                                throw new ClassConstraintException("LocalVariableTable '" + tostring(lvt) + "' references a local variable by the name '"
    285                                        + localname + "' which is not a legal Java simple name.");
    286                            }
    287
    288                            checkIndex(lvt, localvariable.getSignatureIndex(), CONST_Utf8);
    289                            final String localsig = ((ConstantUtf8) cp.getConstant(localvariable.getSignatureIndex())).getBytes(); // Local sig.(=descriptor)
    290                            final Type t;
    291                            try {
    292                                t = Type.getType(localsig);
    293                            } catch (final ClassFormatException cfe) {
    294                                throw new ClassConstraintException("Illegal descriptor (==signature) '" + localsig + "' used by LocalVariable '"
    295                                        + tostring(localvariable) + "' referenced by '" + tostring(lvt) + "'.", cfe);
    296                            }
    297                            final int localindex = localvariable.getIndex();
    298                            if ((t == Type.LONG || t == Type.DOUBLE ? localindex + 1 : localindex) >= obj.getMaxLocals()) {
    299                                throw new ClassConstraintException("LocalVariableTable attribute '" + tostring(lvt) + "' references a LocalVariable '"
    300                                        + tostring(localvariable) + "' with an index that exceeds the surrounding Code attribute's max_locals value of '"
    301                                        + obj.getMaxLocals() + "'.");
    302                            }
    303
    304                            try {
    305                                localVariablesInfos[methodNumber].add(localindex, localname, localvariable.getStartPC(), localvariable.getLength(), t);
    306                            } catch (final LocalVariableInfoInconsistentException lviie) {
    307                                throw new ClassConstraintException("Conflicting information in LocalVariableTable '" + tostring(lvt)
    308                                        + "' found in Code attribute '" + tostring(obj) + "' (method '" + tostring(m) + "'). " + lviie.getMessage(), lviie);
    309                            }
    310                        } // for all local variables localvariables[i] in the LocalVariableTable attribute atts[a] END
    311
    312                        numOfLvtAttribs++;
    313                        if (!m.isStatic() && numOfLvtAttribs > obj.getMaxLocals()) {
    314                            throw new ClassConstraintException("Number of LocalVariableTable attributes of Code attribute '" + tostring(obj) + "' (method '"
    315                                    + tostring(m) + "') exceeds number of local variable slots '" + obj.getMaxLocals()
    316                                    + "' ('There may be at most one LocalVariableTable attribute per local variable in the Code attribute.').");
    317                        }
    318                    } // if atts[a] instanceof LocalVariableTable END
    319                } // for all attributes atts[a] END
    320
    321            } catch (final ClassNotFoundException e) {
    322                // FIXME: this might not be the best way to handle missing classes.
    323                throw new AssertionViolatedException("Missing class: " + e, e);
    324            }
    325
    326        } // visitCode(Code) END
    327
    328        @Override
    329        public void visitCodeException(final CodeException obj) {
    330            // Code constraints are checked in Pass3 (3a and 3b).
    331            // This does not represent an Attribute but is only
    332            // related to internal BCEL data representation.
    333
    334            // see visitCode(Code)
    335        }
    336
    337        /////////////////////////////
    338        // CONSTANTS (vmspec2 4.4) //
    339        /////////////////////////////
    340        @Override
    341        public void visitConstantClass(final ConstantClass obj) {
    342            if (obj.getTag() != Const.CONSTANT_Class) {
    343                throw new ClassConstraintException("Wrong constant tag in '" + tostring(obj) + "'.");
    344            }
    345            checkIndex(obj, obj.getNameIndex(), CONST_Utf8);
    346
    347        }
    348
    349        @Override
    350        public void visitConstantDouble(final ConstantDouble obj) {
    351            if (obj.getTag() != Const.CONSTANT_Double) {
    352                throw new ClassConstraintException("Wrong constant tag in '" + tostring(obj) + "'.");
    353            }
    354            // no indices to check
    355        }
    356
    357        @Override
    358        public void visitConstantFieldref(final ConstantFieldref obj) {
    359            if (obj.getTag() != Const.CONSTANT_Fieldref) {
    360                throw new ClassConstraintException("Wrong constant tag in '" + tostring(obj) + "'.");
    361            }
    362            checkIndex(obj, obj.getClassIndex(), CONST_Class);
    363            checkIndex(obj, obj.getNameAndTypeIndex(), CONST_NameAndType);
    364        }
    365
    366        @Override
    367        public void visitConstantFloat(final ConstantFloat obj) {
    368            if (obj.getTag() != Const.CONSTANT_Float) {
    369                throw new ClassConstraintException("Wrong constant tag in '" + tostring(obj) + "'.");
    370            }
    371            // no indices to check
    372        }
    373
    374        @Override
    375        public void visitConstantInteger(final ConstantInteger obj) {
    376            if (obj.getTag() != Const.CONSTANT_Integer) {
    377                throw new ClassConstraintException("Wrong constant tag in '" + tostring(obj) + "'.");
    378            }
    379            // no indices to check
    380        }
    381
    382        @Override
    383        public void visitConstantInterfaceMethodref(final ConstantInterfaceMethodref obj) {
    384            if (obj.getTag() != Const.CONSTANT_InterfaceMethodref) {
    385                throw new ClassConstraintException("Wrong constant tag in '" + tostring(obj) + "'.");
    386            }
    387            checkIndex(obj, obj.getClassIndex(), CONST_Class);
    388            checkIndex(obj, obj.getNameAndTypeIndex(), CONST_NameAndType);
    389        }
    390
    391        @Override
    392        public void visitConstantLong(final ConstantLong obj) {
    393            if (obj.getTag() != Const.CONSTANT_Long) {
    394                throw new ClassConstraintException("Wrong constant tag in '" + tostring(obj) + "'.");
    395            }
    396            // no indices to check
    397        }
    398
    399        @Override
    400        public void visitConstantMethodref(final ConstantMethodref obj) {
    401            if (obj.getTag() != Const.CONSTANT_Methodref) {
    402                throw new ClassConstraintException("Wrong constant tag in '" + tostring(obj) + "'.");
    403            }
    404            checkIndex(obj, obj.getClassIndex(), CONST_Class);
    405            checkIndex(obj, obj.getNameAndTypeIndex(), CONST_NameAndType);
    406        }
    407
    408        @Override
    409        public void visitConstantNameAndType(final ConstantNameAndType obj) {
    410            if (obj.getTag() != Const.CONSTANT_NameAndType) {
    411                throw new ClassConstraintException("Wrong constant tag in '" + tostring(obj) + "'.");
    412            }
    413            checkIndex(obj, obj.getNameIndex(), CONST_Utf8);
    414            // checkIndex(obj, obj.getDescriptorIndex(), CONST_Utf8); //inconsistently named in BCEL, see below.
    415            checkIndex(obj, obj.getSignatureIndex(), CONST_Utf8);
    416        }
    417
    418        @Override
    419        public void visitConstantPool(final ConstantPool obj) {
    420            // No need to. We're piggybacked by the DescendingVisitor.
    421            // This does not represent an Attribute but is only
    422            // related to internal BCEL data representation.
    423        }
    424
    425        @Override
    426        public void visitConstantString(final ConstantString obj) {
    427            if (obj.getTag() != Const.CONSTANT_String) {
    428                throw new ClassConstraintException("Wrong constant tag in '" + tostring(obj) + "'.");
    429            }
    430            checkIndex(obj, obj.getStringIndex(), CONST_Utf8);
    431        }
    432
    433        @Override
    434        public void visitConstantUtf8(final ConstantUtf8 obj) {
    435            if (obj.getTag() != Const.CONSTANT_Utf8) {
    436                throw new ClassConstraintException("Wrong constant tag in '" + tostring(obj) + "'.");
    437            }
    438            // no indices to check
    439        }
    440
    441        ////////////////////////////////////////////////////////
    442        // field_info-structure-ATTRIBUTES (vmspec2 4.5, 4.7) //
    443        ////////////////////////////////////////////////////////
    444        @Override
    445        public void visitConstantValue(final ConstantValue obj) { // vmspec2 4.7.2
    446            // Despite its name, this really is an Attribute,
    447            // not a constant!
    448            checkIndex(obj, obj.getNameIndex(), CONST_Utf8);
    449
    450            final String name = ((ConstantUtf8) cp.getConstant(obj.getNameIndex())).getBytes();
    451            if (!name.equals("ConstantValue")) {
    452                throw new ClassConstraintException(
    453                    "The ConstantValue attribute '" + tostring(obj) + "' is not correctly named 'ConstantValue' but '" + name + "'.");
    454            }
    455
    456            final Object pred = carrier.predecessor();
    457            if (pred instanceof Field) { // ConstantValue attributes are quite senseless if the predecessor is not a field.
    458                final Field f = (Field) pred;
    459                // Field constraints have been checked before -- so we are safe using their type information.
    460                final Type fieldType = Type.getType(((ConstantUtf8) cp.getConstant(f.getSignatureIndex())).getBytes());
    461
    462                final int index = obj.getConstantValueIndex();
    463                if (index < 0 || index >= cplen) {
    464                    throw new ClassConstraintException("Invalid index '" + index + "' used by '" + tostring(obj) + "'.");
    465                }
    466                final Constant c = cp.getConstant(index);
    467
    468                if (CONST_Long.isInstance(c) && fieldType.equals(Type.LONG) || CONST_Float.isInstance(c) && fieldType.equals(Type.FLOAT)) {
    469                    return;
    470                }
    471                if (CONST_Double.isInstance(c) && fieldType.equals(Type.DOUBLE)) {
    472                    return;
    473                }
    474                if (CONST_Integer.isInstance(c) && (fieldType.equals(Type.INT) || fieldType.equals(Type.SHORT) || fieldType.equals(Type.CHAR)
    475                    || fieldType.equals(Type.BYTE) || fieldType.equals(Type.BOOLEAN))) {
    476                    return;
    477                }
    478                if (CONST_String.isInstance(c) && fieldType.equals(Type.STRING)) {
    479                    return;
    480                }
    481
    482                throw new ClassConstraintException("Illegal type of ConstantValue '" + obj + "' embedding Constant '" + c + "'. It is referenced by field '"
    483                    + tostring(f) + "' expecting a different type: '" + fieldType + "'.");
    484            }
    485        }
    486
    487        @Override
    488        public void visitDeprecated(final Deprecated obj) { // vmspec2 4.7.10
    489            checkIndex(obj, obj.getNameIndex(), CONST_Utf8);
    490
    491            final String name = ((ConstantUtf8) cp.getConstant(obj.getNameIndex())).getBytes();
    492            if (!name.equals("Deprecated")) {
    493                throw new ClassConstraintException("The Deprecated attribute '" + tostring(obj) + "' is not correctly named 'Deprecated' but '" + name + "'.");
    494            }
    495        }
    496
    497        @Override
    498        public void visitExceptionTable(final ExceptionTable obj) { // vmspec2 4.7.4
    499            try {
    500                // incorrectly named, it's the Exceptions attribute (vmspec2 4.7.4)
    501                checkIndex(obj, obj.getNameIndex(), CONST_Utf8);
    502
    503                final String name = ((ConstantUtf8) cp.getConstant(obj.getNameIndex())).getBytes();
    504                if (!name.equals("Exceptions")) {
    505                    throw new ClassConstraintException(
    506                        "The Exceptions attribute '" + tostring(obj) + "' is not correctly named 'Exceptions' but '" + name + "'.");
    507                }
    508
    509                final int[] excIndices = obj.getExceptionIndexTable();
    510
    511                for (final int excIndice : excIndices) {
    512                    checkIndex(obj, excIndice, CONST_Class);
    513
    514                    final ConstantClass cc = (ConstantClass) cp.getConstant(excIndice);
    515                    checkIndex(cc, cc.getNameIndex(), CONST_Utf8); // can't be sure this ConstantClass has already been visited (checked)!
    516                    // convert internal notation on-the-fly to external notation:
    517                    final String cname = Utility.pathToPackage(((ConstantUtf8) cp.getConstant(cc.getNameIndex())).getBytes());
    518
    519                    Verifier v = VerifierFactory.getVerifier(cname);
    520                    VerificationResult vr = v.doPass1();
    521
    522                    if (vr != VerificationResult.VR_OK) {
    523                        throw new ClassConstraintException("Exceptions attribute '" + tostring(obj) + "' references '" + cname
    524                            + "' as an Exception but it does not pass verification pass 1: " + vr);
    525                    }
    526                    // We cannot safely trust any other "instanceof" mechanism. We need to transitively verify
    527                    // the ancestor hierarchy.
    528                    JavaClass e = Repository.lookupClass(cname);
    529                    final JavaClass t = Repository.lookupClass(Type.THROWABLE.getClassName());
    530                    final JavaClass o = Repository.lookupClass(Type.OBJECT.getClassName());
    531                    while (e != o) {
    532                        if (e == t) {
    533                            break; // It's a subclass of Throwable, OKAY, leave.
    534                        }
    535
    536                        v = VerifierFactory.getVerifier(e.getSuperclassName());
    537                        vr = v.doPass1();
    538                        if (vr != VerificationResult.VR_OK) {
    539                            throw new ClassConstraintException("Exceptions attribute '" + tostring(obj) + "' references '" + cname + "' as an Exception but '"
    540                                + e.getSuperclassName() + "' in the ancestor hierachy does not pass verification pass 1: " + vr);
    541                        }
    542                        e = Repository.lookupClass(e.getSuperclassName());
    543                    }
    544                    if (e != t) {
    545                        throw new ClassConstraintException("Exceptions attribute '" + tostring(obj) + "' references '" + cname
    546                            + "' as an Exception but it is not a subclass of '" + t.getClassName() + "'.");
    547                    }
    548                }
    549
    550            } catch (final ClassNotFoundException e) {
    551                // FIXME: this might not be the best way to handle missing classes.
    552                throw new AssertionViolatedException("Missing class: " + e, e);
    553            }
    554        }
    555
    556        //////////////////////////
    557        // FIELDS (vmspec2 4.5) //
    558        //////////////////////////
    559        @Override
    560        public void visitField(final Field obj) {
    561
    562            if (jc.isClass()) {
    563                int maxone = 0;
    564                if (obj.isPrivate()) {
    565                    maxone++;
    566                }
    567                if (obj.isProtected()) {
    568                    maxone++;
    569                }
    570                if (obj.isPublic()) {
    571                    maxone++;
    572                }
    573                if (maxone > 1) {
    574                    throw new ClassConstraintException(
    575                        "Field '" + tostring(obj) + "' must only have at most one of its ACC_PRIVATE, ACC_PROTECTED, ACC_PUBLIC modifiers set.");
    576                }
    577
    578                if (obj.isFinal() && obj.isVolatile()) {
    579                    throw new ClassConstraintException(
    580                        "Field '" + tostring(obj) + "' must only have at most one of its ACC_FINAL, ACC_VOLATILE modifiers set.");
    581                }
    582            } else { // isInterface!
    583                if (!obj.isPublic()) {
    584                    throw new ClassConstraintException("Interface field '" + tostring(obj) + "' must have the ACC_PUBLIC modifier set but hasn't!");
    585                }
    586                if (!obj.isStatic()) {
    587                    throw new ClassConstraintException("Interface field '" + tostring(obj) + "' must have the ACC_STATIC modifier set but hasn't!");
    588                }
    589                if (!obj.isFinal()) {
    590                    throw new ClassConstraintException("Interface field '" + tostring(obj) + "' must have the ACC_FINAL modifier set but hasn't!");
    591                }
    592            }
    593
    594            if ((obj.getAccessFlags() & ~(Const.ACC_PUBLIC | Const.ACC_PRIVATE | Const.ACC_PROTECTED | Const.ACC_STATIC | Const.ACC_FINAL | Const.ACC_VOLATILE |
    595                Const.ACC_TRANSIENT)) > 0) {
    596                addMessage("Field '" + tostring(obj) + "' has access flag(s) other than ACC_PUBLIC, ACC_PRIVATE, ACC_PROTECTED,"
    597                    + " ACC_STATIC, ACC_FINAL, ACC_VOLATILE, ACC_TRANSIENT set (ignored).");
    598            }
    599
    600            checkIndex(obj, obj.getNameIndex(), CONST_Utf8);
    601
    602            final String name = obj.getName();
    603            if (!validFieldName(name)) {
    604                throw new ClassConstraintException("Field '" + tostring(obj) + "' has illegal name '" + obj.getName() + "'.");
    605            }
    606
    607            // A descriptor is often named signature in BCEL
    608            checkIndex(obj, obj.getSignatureIndex(), CONST_Utf8);
    609
    610            final String sig = ((ConstantUtf8) cp.getConstant(obj.getSignatureIndex())).getBytes(); // Field or Method sig.(=descriptor)
    611
    612            try {
    613                Type.getType(sig); /* Don't need the return value */
    614            } catch (final ClassFormatException cfe) {
    615                throw new ClassConstraintException("Illegal descriptor (==signature) '" + sig + "' used by '" + tostring(obj) + "'.", cfe);
    616            }
    617
    618            final String nameanddesc = name + sig;
    619            if (fieldNamesAndDesc.contains(nameanddesc)) {
    620                throw new ClassConstraintException("No two fields (like '" + tostring(obj) + "') are allowed have same names and descriptors!");
    621            }
    622            if (fieldNames.contains(name)) {
    623                addMessage("More than one field of name '" + name + "' detected (but with different type descriptors). This is very unusual.");
    624            }
    625            fieldNamesAndDesc.add(nameanddesc);
    626            fieldNames.add(name);
    627
    628            final Attribute[] atts = obj.getAttributes();
    629            for (final Attribute att : atts) {
    630                if (!(att instanceof ConstantValue) && !(att instanceof Synthetic) && !(att instanceof Deprecated)) {
    631                    addMessage("Attribute '" + tostring(att) + "' as an attribute of Field '" + tostring(obj) + "' is unknown and will therefore be ignored.");
    632                }
    633                if (!(att instanceof ConstantValue)) {
    634                    addMessage("Attribute '" + tostring(att) + "' as an attribute of Field '" + tostring(obj)
    635                        + "' is not a ConstantValue and is therefore only of use for debuggers and such.");
    636                }
    637            }
    638        }
    639
    640        @Override
    641        public void visitInnerClass(final InnerClass obj) {
    642            // This does not represent an Attribute but is only
    643            // related to internal BCEL data representation.
    644        }
    645
    646        @Override
    647        public void visitInnerClasses(final InnerClasses innerClasses) { // vmspec2 4.7.5
    648
    649            // exactly one InnerClasses attr per ClassFile if some inner class is refernced: see visitJavaClass()
    650
    651            checkIndex(innerClasses, innerClasses.getNameIndex(), CONST_Utf8);
    652
    653            final String name = ((ConstantUtf8) cp.getConstant(innerClasses.getNameIndex())).getBytes();
    654            if (!name.equals("InnerClasses")) {
    655                throw new ClassConstraintException(
    656                    "The InnerClasses attribute '" + tostring(innerClasses) + "' is not correctly named 'InnerClasses' but '" + name + "'.");
    657            }
    658
    659            innerClasses.forEach(ic -> {
    660                checkIndex(innerClasses, ic.getInnerClassIndex(), CONST_Class);
    661                final int outerIdx = ic.getOuterClassIndex();
    662                if (outerIdx != 0) {
    663                    checkIndex(innerClasses, outerIdx, CONST_Class);
    664                }
    665                final int innernameIdx = ic.getInnerNameIndex();
    666                if (innernameIdx != 0) {
    667                    checkIndex(innerClasses, innernameIdx, CONST_Utf8);
    668                }
    669                int acc = ic.getInnerAccessFlags();
    670                acc &= ~(Const.ACC_PUBLIC | Const.ACC_PRIVATE | Const.ACC_PROTECTED | Const.ACC_STATIC | Const.ACC_FINAL | Const.ACC_INTERFACE |
    671                    Const.ACC_ABSTRACT);
    672                if (acc != 0) {
    673                    addMessage("Unknown access flag for inner class '" + tostring(ic) + "' set (InnerClasses attribute '" + tostring(innerClasses) + "').");
    674                }
    675            });
    676            // Semantical consistency is not yet checked by Sun, see vmspec2 4.7.5.
    677            // [marked TODO in JustIce]
    678        }
    679
    680        ///////////////////////////////////////
    681        // ClassFile structure (vmspec2 4.1) //
    682        ///////////////////////////////////////
    683        @Override
    684        public void visitJavaClass(final JavaClass obj) {
    685            final Attribute[] atts = obj.getAttributes();
    686            boolean foundSourceFile = false;
    687            boolean foundInnerClasses = false;
    688
    689            // Is there an InnerClass referenced?
    690            // This is a costly check; existing verifiers don't do it!
    691            final boolean hasInnerClass = new InnerClassDetector(jc).innerClassReferenced();
    692
    693            for (final Attribute att : atts) {
    694                if (!(att instanceof SourceFile) && !(att instanceof Deprecated) && !(att instanceof InnerClasses) && !(att instanceof Synthetic)) {
    695                    addMessage("Attribute '" + tostring(att) + "' as an attribute of the ClassFile structure '" + tostring(obj)
    696                        + "' is unknown and will therefore be ignored.");
    697                }
    698
    699                if (att instanceof SourceFile) {
    700                    if (foundSourceFile) {
    701                        throw new ClassConstraintException(
    702                            "A ClassFile structure (like '" + tostring(obj) + "') may have no more than one SourceFile attribute."); // vmspec2 4.7.7
    703                    }
    704                    foundSourceFile = true;
    705                }
    706
    707                if (att instanceof InnerClasses) {
    708                    if (!foundInnerClasses) {
    709                        foundInnerClasses = true;
    710                    } else if (hasInnerClass) {
    711                        throw new ClassConstraintException("A Classfile structure (like '" + tostring(obj) + "') must have exactly one InnerClasses attribute"
    712                            + " if at least one Inner Class is referenced (which is the case). More than one InnerClasses attribute was found.");
    713                    }
    714                    if (!hasInnerClass) {
    715                        addMessage("No referenced Inner Class found, but InnerClasses attribute '" + tostring(att)
    716                            + "' found. Strongly suggest removal of that attribute.");
    717                    }
    718                }
    719
    720            }
    721            if (hasInnerClass && !foundInnerClasses) {
    722                // throw new ClassConstraintException("A Classfile structure (like '"+tostring(obj)+
    723                // "') must have exactly one InnerClasses attribute if at least one Inner Class is referenced (which is the case)."+
    724                // " No InnerClasses attribute was found.");
    725                // vmspec2, page 125 says it would be a constraint: but existing verifiers
    726                // don't check it and javac doesn't satisfy it when it comes to anonymous
    727                // inner classes
    728                addMessage("A Classfile structure (like '" + tostring(obj)
    729                    + "') must have exactly one InnerClasses attribute if at least one Inner Class is referenced (which is the case)."
    730                    + " No InnerClasses attribute was found.");
    731            }
    732        }
    733
    734        @Override
    735        public void visitLineNumber(final LineNumber obj) {
    736            // This does not represent an Attribute but is only
    737            // related to internal BCEL data representation.
    738
    739            // see visitLineNumberTable(LineNumberTable)
    740        }
    741
    742        // SYNTHETIC: see above
    743        // DEPRECATED: see above
    744        //////////////////////////////////////////////////////////////
    745        // code_attribute-structure-ATTRIBUTES (vmspec2 4.7.3, 4.7) //
    746        //////////////////////////////////////////////////////////////
    747        @Override
    748        public void visitLineNumberTable(final LineNumberTable obj) { // vmspec2 4.7.8
    749            checkIndex(obj, obj.getNameIndex(), CONST_Utf8);
    750
    751            final String name = ((ConstantUtf8) cp.getConstant(obj.getNameIndex())).getBytes();
    752            if (!name.equals("LineNumberTable")) {
    753                throw new ClassConstraintException(
    754                    "The LineNumberTable attribute '" + tostring(obj) + "' is not correctly named 'LineNumberTable' but '" + name + "'.");
    755            }
    756
    757            // In JustIce, this check is delayed to Pass 3a.
    758            // LineNumber[] linenumbers = obj.getLineNumberTable();
    759            // ...validity check...
    760
    761        }
    762
    763        //////////
    764        // BCEL //
    765        //////////
    766        @Override
    767        public void visitLocalVariable(final LocalVariable obj) {
    768            // This does not represent an Attribute but is only
    769            // related to internal BCEL data representation.
    770
    771            // see visitLocalVariableTable(LocalVariableTable)
    772        }
    773
    774        @Override
    775        public void visitLocalVariableTable(final LocalVariableTable obj) { // vmspec2 4.7.9
    776            // In JustIce, this check is partially delayed to Pass 3a.
    777            // The other part can be found in the visitCode(Code) method.
    778        }
    779
    780        ///////////////////////////
    781        // METHODS (vmspec2 4.6) //
    782        ///////////////////////////
    783        @Override
    784        public void visitMethod(final Method obj) {
    785
    786            checkIndex(obj, obj.getNameIndex(), CONST_Utf8);
    787
    788            final String name = obj.getName();
    789            if (!validMethodName(name, true)) {
    790                throw new ClassConstraintException("Method '" + tostring(obj) + "' has illegal name '" + name + "'.");
    791            }
    792
    793            // A descriptor is often named signature in BCEL
    794            checkIndex(obj, obj.getSignatureIndex(), CONST_Utf8);
    795
    796            final String sig = ((ConstantUtf8) cp.getConstant(obj.getSignatureIndex())).getBytes(); // Method's signature(=descriptor)
    797
    798            final Type t;
    799            final Type[] ts; // needed below the try block.
    800            try {
    801                t = Type.getReturnType(sig);
    802                ts = Type.getArgumentTypes(sig);
    803            } catch (final ClassFormatException cfe) {
    804                throw new ClassConstraintException("Illegal descriptor (==signature) '" + sig + "' used by Method '" + tostring(obj) + "'.", cfe);
    805            }
    806
    807            // Check if referenced objects exist.
    808            Type act = t;
    809            if (act instanceof ArrayType) {
    810                act = ((ArrayType) act).getBasicType();
    811            }
    812            if (act instanceof ObjectType) {
    813                final Verifier v = VerifierFactory.getVerifier(((ObjectType) act).getClassName());
    814                final VerificationResult vr = v.doPass1();
    815                if (vr != VerificationResult.VR_OK) {
    816                    throw new ClassConstraintException(
    817                        "Method '" + tostring(obj) + "' has a return type that does not pass verification pass 1: '" + vr + "'.");
    818                }
    819            }
    820
    821            for (final Type element : ts) {
    822                act = element;
    823                if (act instanceof ArrayType) {
    824                    act = ((ArrayType) act).getBasicType();
    825                }
    826                if (act instanceof ObjectType) {
    827                    final Verifier v = VerifierFactory.getVerifier(((ObjectType) act).getClassName());
    828                    final VerificationResult vr = v.doPass1();
    829                    if (vr != VerificationResult.VR_OK) {
    830                        throw new ClassConstraintException(
    831                            "Method '" + tostring(obj) + "' has an argument type that does not pass verification pass 1: '" + vr + "'.");
    832                    }
    833                }
    834            }
    835
    836            // Nearly forgot this! Funny return values are allowed, but a non-empty arguments list makes a different method out of
    837            // it!
    838            if (name.equals(Const.STATIC_INITIALIZER_NAME) && ts.length != 0) {
    839                throw new ClassConstraintException("Method '" + tostring(obj) + "' has illegal name '" + name + "'."
    840                    + " Its name resembles the class or interface initialization method which it isn't because of its arguments (==descriptor).");
    841            }
    842
    843            if (jc.isClass()) {
    844                int maxone = 0;
    845                if (obj.isPrivate()) {
    846                    maxone++;
    847                }
    848                if (obj.isProtected()) {
    849                    maxone++;
    850                }
    851                if (obj.isPublic()) {
    852                    maxone++;
    853                }
    854                if (maxone > 1) {
    855                    throw new ClassConstraintException(
    856                        "Method '" + tostring(obj) + "' must only have at most one of its ACC_PRIVATE, ACC_PROTECTED, ACC_PUBLIC modifiers set.");
    857                }
    858
    859                if (obj.isAbstract()) {
    860                    if (obj.isFinal()) {
    861                        throw new ClassConstraintException("Abstract method '" + tostring(obj) + "' must not have the ACC_FINAL modifier set.");
    862                    }
    863                    if (obj.isNative()) {
    864                        throw new ClassConstraintException("Abstract method '" + tostring(obj) + "' must not have the ACC_NATIVE modifier set.");
    865                    }
    866                    if (obj.isPrivate()) {
    867                        throw new ClassConstraintException("Abstract method '" + tostring(obj) + "' must not have the ACC_PRIVATE modifier set.");
    868                    }
    869                    if (obj.isStatic()) {
    870                        throw new ClassConstraintException("Abstract method '" + tostring(obj) + "' must not have the ACC_STATIC modifier set.");
    871                    }
    872                    if (obj.isStrictfp()) {
    873                        throw new ClassConstraintException("Abstract method '" + tostring(obj) + "' must not have the ACC_STRICT modifier set.");
    874                    }
    875                    if (obj.isSynchronized()) {
    876                        throw new ClassConstraintException("Abstract method '" + tostring(obj) + "' must not have the ACC_SYNCHRONIZED modifier set.");
    877                    }
    878                }
    879
    880                // A specific instance initialization method... (vmspec2,Page 116).
    881                // ..may have at most one of ACC_PRIVATE, ACC_PROTECTED, ACC_PUBLIC set: is checked above.
    882                // ..may also have ACC_STRICT set, but none of the other flags in table 4.5 (vmspec2, page 115)
    883                if (name.equals(Const.CONSTRUCTOR_NAME) && (obj.isStatic() || obj.isFinal() || obj.isSynchronized() || obj.isNative() || obj.isAbstract())) {
    884                    throw new ClassConstraintException("Instance initialization method '" + tostring(obj) + "' must not have"
    885                            + " any of the ACC_STATIC, ACC_FINAL, ACC_SYNCHRONIZED, ACC_NATIVE, ACC_ABSTRACT modifiers set.");
    886                }
    887            } else if (!name.equals(Const.STATIC_INITIALIZER_NAME)) { // vmspec2, p.116, 2nd paragraph
    888                if (jc.getMajor() >= Const.MAJOR_1_8) {
    889                    if (obj.isPublic() == obj.isPrivate()) {
    890                        throw new ClassConstraintException(
    891                            "Interface method '" + tostring(obj) + "' must have exactly one of its ACC_PUBLIC and ACC_PRIVATE modifiers set.");
    892                    }
    893                    if (obj.isProtected() || obj.isFinal() || obj.isSynchronized() || obj.isNative()) {
    894                        throw new ClassConstraintException("Interface method '" + tostring(obj) + "' must not have"
    895                            + " any of the ACC_PROTECTED, ACC_FINAL, ACC_SYNCHRONIZED, or ACC_NATIVE modifiers set.");
    896                    }
    897
    898                } else {
    899                    if (!obj.isPublic()) {
    900                        throw new ClassConstraintException("Interface method '" + tostring(obj) + "' must have the ACC_PUBLIC modifier set but hasn't!");
    901                    }
    902                    if (!obj.isAbstract()) {
    903                        throw new ClassConstraintException("Interface method '" + tostring(obj) + "' must have the ACC_ABSTRACT modifier set but hasn't!");
    904                    }
    905                    if (obj.isPrivate() || obj.isProtected() || obj.isStatic() || obj.isFinal() || obj.isSynchronized() || obj.isNative() || obj.isStrictfp()) {
    906                        throw new ClassConstraintException("Interface method '" + tostring(obj) + "' must not have"
    907                            + " any of the ACC_PRIVATE, ACC_PROTECTED, ACC_STATIC, ACC_FINAL, ACC_SYNCHRONIZED,"
    908                            + " ACC_NATIVE, ACC_ABSTRACT, ACC_STRICT modifiers set.");
    909                    }
    910                }
    911            }
    912
    913            if ((obj.getAccessFlags() & ~(Const.ACC_PUBLIC | Const.ACC_PRIVATE | Const.ACC_PROTECTED | Const.ACC_STATIC | Const.ACC_FINAL |
    914                Const.ACC_SYNCHRONIZED | Const.ACC_NATIVE | Const.ACC_ABSTRACT | Const.ACC_STRICT)) > 0) {
    915                addMessage("Method '" + tostring(obj) + "' has access flag(s) other than ACC_PUBLIC, ACC_PRIVATE, ACC_PROTECTED, ACC_STATIC, ACC_FINAL,"
    916                    + " ACC_SYNCHRONIZED, ACC_NATIVE, ACC_ABSTRACT, ACC_STRICT set (ignored).");
    917            }
    918
    919            final String nameanddesc = name + sig;
    920            if (methodNamesAndDesc.contains(nameanddesc)) {
    921                throw new ClassConstraintException("No two methods (like '" + tostring(obj) + "') are allowed have same names and desciptors!");
    922            }
    923            methodNamesAndDesc.add(nameanddesc);
    924
    925            final Attribute[] atts = obj.getAttributes();
    926            int numCodeAtts = 0;
    927            for (final Attribute att : atts) {
    928                if (!(att instanceof Code) && !(att instanceof ExceptionTable) && !(att instanceof Synthetic) && !(att instanceof Deprecated)) {
    929                    addMessage("Attribute '" + tostring(att) + "' as an attribute of Method '" + tostring(obj) + "' is unknown and will therefore be ignored.");
    930                }
    931                if (!(att instanceof Code) && !(att instanceof ExceptionTable)) {
    932                    addMessage("Attribute '" + tostring(att) + "' as an attribute of Method '" + tostring(obj)
    933                        + "' is neither Code nor Exceptions and is therefore only of use for debuggers and such.");
    934                }
    935                if (att instanceof Code && (obj.isNative() || obj.isAbstract())) {
    936                    throw new ClassConstraintException(
    937                        "Native or abstract methods like '" + tostring(obj) + "' must not have a Code attribute like '" + tostring(att) + "'."); // vmspec2
    938                                                                                                                                                 // page120,
    939                                                                                                                                                 // 4.7.3
    940                }
    941                if (att instanceof Code) {
    942                    numCodeAtts++;
    943                }
    944            }
    945            if (!obj.isNative() && !obj.isAbstract() && numCodeAtts != 1) {
    946                throw new ClassConstraintException(
    947                    "Non-native, non-abstract methods like '" + tostring(obj) + "' must have exactly one Code attribute (found: " + numCodeAtts + ").");
    948            }
    949        }
    950
    951        ///////////////////////////////////////////////////////
    952        // ClassFile-structure-ATTRIBUTES (vmspec2 4.1, 4.7) //
    953        ///////////////////////////////////////////////////////
    954        @Override
    955        public void visitSourceFile(final SourceFile obj) { // vmspec2 4.7.7
    956
    957            // zero or one SourceFile attr per ClassFile: see visitJavaClass()
    958
    959            checkIndex(obj, obj.getNameIndex(), CONST_Utf8);
    960
    961            final String name = ((ConstantUtf8) cp.getConstant(obj.getNameIndex())).getBytes();
    962            if (!name.equals("SourceFile")) {
    963                throw new ClassConstraintException("The SourceFile attribute '" + tostring(obj) + "' is not correctly named 'SourceFile' but '" + name + "'.");
    964            }
    965
    966            checkIndex(obj, obj.getSourceFileIndex(), CONST_Utf8);
    967
    968            final String sourceFileName = ((ConstantUtf8) cp.getConstant(obj.getSourceFileIndex())).getBytes(); // ==obj.getSourceFileName() ?
    969            final String sourceFileNameLc = StringUtils.toRootLowerCase(sourceFileName);
    970
    971            if (sourceFileName.indexOf('/') != -1 || sourceFileName.indexOf('\\') != -1 || sourceFileName.indexOf(':') != -1
    972                || sourceFileNameLc.lastIndexOf(".java") == -1) {
    973                addMessage("SourceFile attribute '" + tostring(obj)
    974                    + "' has a funny name: remember not to confuse certain parsers working on javap's output. Also, this name ('" + sourceFileName
    975                    + "') is considered an unqualified (simple) file name only.");
    976            }
    977        }
    978
    979        @Override
    980        public void visitSynthetic(final Synthetic obj) { // vmspec2 4.7.6
    981            checkIndex(obj, obj.getNameIndex(), CONST_Utf8);
    982            final String name = ((ConstantUtf8) cp.getConstant(obj.getNameIndex())).getBytes();
    983            if (!name.equals("Synthetic")) {
    984                throw new ClassConstraintException("The Synthetic attribute '" + tostring(obj) + "' is not correctly named 'Synthetic' but '" + name + "'.");
    985            }
    986        }
    987
    988        ////////////////////////////////////////////////////
    989        // MISC-structure-ATTRIBUTES (vmspec2 4.7.1, 4.7) //
    990        ////////////////////////////////////////////////////
    991        @Override
    992        public void visitUnknown(final Unknown obj) { // vmspec2 4.7.1
    993            // Represents an unknown attribute.
    994            checkIndex(obj, obj.getNameIndex(), CONST_Utf8);
    995
    996            // Maybe only misnamed? Give a (warning) message.
    997            addMessage("Unknown attribute '" + tostring(obj) + "'. This attribute is not known in any context!");
    998        }
    999    }
    1000
    1001    /**
    1002     * A Visitor class that ensures the ConstantCP-subclassed entries of the constant pool are valid. <B>Precondition:
    1003     * index-style cross referencing in the constant pool must be valid.</B>
    1004     *
    1005     * @see #constantPoolEntriesSatisfyStaticConstraints()
    1006     * @see org.apache.bcel.classfile.ConstantCP
    1007     */
    1008    private final class FAMRAV_Visitor extends EmptyVisitor {
    1009        private final ConstantPool cp; // ==jc.getConstantPool() -- only here to save typing work.
    1010
    1011        private FAMRAV_Visitor(final JavaClass jc) {
    1012            this.cp = jc.getConstantPool();
    1013        }
    1014
    1015        @Override
    1016        public void visitConstantFieldref(final ConstantFieldref obj) {
    1017            if (obj.getTag() != Const.CONSTANT_Fieldref) {
    1018                throw new ClassConstraintException("ConstantFieldref '" + tostring(obj) + "' has wrong tag!");
    1019            }
    1020            final int nameAndTypeIndex = obj.getNameAndTypeIndex();
    1021            final ConstantNameAndType cnat = (ConstantNameAndType) cp.getConstant(nameAndTypeIndex);
    1022            final String name = ((ConstantUtf8) cp.getConstant(cnat.getNameIndex())).getBytes(); // Field or Method name
    1023            if (!validFieldName(name)) {
    1024                throw new ClassConstraintException("Invalid field name '" + name + "' referenced by '" + tostring(obj) + "'.");
    1025            }
    1026
    1027            final int classIndex = obj.getClassIndex();
    1028            final ConstantClass cc = (ConstantClass) cp.getConstant(classIndex);
    1029            final String className = ((ConstantUtf8) cp.getConstant(cc.getNameIndex())).getBytes(); // Class Name in internal form
    1030            if (!validClassName(className)) {
    1031                throw new ClassConstraintException("Illegal class name '" + className + "' used by '" + tostring(obj) + "'.");
    1032            }
    1033
    1034            final String sig = ((ConstantUtf8) cp.getConstant(cnat.getSignatureIndex())).getBytes(); // Field or Method sig.(=descriptor)
    1035
    1036            try {
    1037                Type.getType(sig); /* Don't need the return value */
    1038            } catch (final ClassFormatException cfe) {
    1039                throw new ClassConstraintException("Illegal descriptor (==signature) '" + sig + "' used by '" + tostring(obj) + "'.", cfe);
    1040            }
    1041        }
    1042
    1043        @Override
    1044        public void visitConstantInterfaceMethodref(final ConstantInterfaceMethodref obj) {
    1045            if (obj.getTag() != Const.CONSTANT_InterfaceMethodref) {
    1046                throw new ClassConstraintException("ConstantInterfaceMethodref '" + tostring(obj) + "' has wrong tag!");
    1047            }
    1048            final int nameAndTypeIndex = obj.getNameAndTypeIndex();
    1049            final ConstantNameAndType cnat = (ConstantNameAndType) cp.getConstant(nameAndTypeIndex);
    1050            final String name = ((ConstantUtf8) cp.getConstant(cnat.getNameIndex())).getBytes(); // Field or Method name
    1051            if (!validInterfaceMethodName(name)) {
    1052                throw new ClassConstraintException("Invalid (interface) method name '" + name + "' referenced by '" + tostring(obj) + "'.");
    1053            }
    1054
    1055            final int classIndex = obj.getClassIndex();
    1056            final ConstantClass cc = (ConstantClass) cp.getConstant(classIndex);
    1057            final String className = ((ConstantUtf8) cp.getConstant(cc.getNameIndex())).getBytes(); // Class Name in internal form
    1058            if (!validClassName(className)) {
    1059                throw new ClassConstraintException("Illegal class name '" + className + "' used by '" + tostring(obj) + "'.");
    1060            }
    1061
    1062            final String sig = ((ConstantUtf8) cp.getConstant(cnat.getSignatureIndex())).getBytes(); // Field or Method sig.(=descriptor)
    1063
    1064            try {
    1065                final Type t = Type.getReturnType(sig);
    1066                if (name.equals(Const.STATIC_INITIALIZER_NAME) && t != Type.VOID) {
    1067                    addMessage("Class or interface initialization method '" + Const.STATIC_INITIALIZER_NAME + "' usually has VOID return type instead of '" + t
    1068                        + "'. Note this is really not a requirement of The Java Virtual Machine Specification, Second Edition.");
    1069                }
    1070            } catch (final ClassFormatException cfe) {
    1071                throw new ClassConstraintException("Illegal descriptor (==signature) '" + sig + "' used by '" + tostring(obj) + "'.", cfe);
    1072            }
    1073
    1074        }
    1075
    1076        @Override
    1077        public void visitConstantMethodref(final ConstantMethodref obj) {
    1078            if (obj.getTag() != Const.CONSTANT_Methodref) {
    1079                throw new ClassConstraintException("ConstantMethodref '" + tostring(obj) + "' has wrong tag!");
    1080            }
    1081            final int nameAndTypeIndex = obj.getNameAndTypeIndex();
    1082            final ConstantNameAndType cnat = (ConstantNameAndType) cp.getConstant(nameAndTypeIndex);
    1083            final String name = ((ConstantUtf8) cp.getConstant(cnat.getNameIndex())).getBytes(); // Field or Method name
    1084            if (!validClassMethodName(name)) {
    1085                throw new ClassConstraintException("Invalid (non-interface) method name '" + name + "' referenced by '" + tostring(obj) + "'.");
    1086            }
    1087
    1088            final int classIndex = obj.getClassIndex();
    1089            final ConstantClass cc = (ConstantClass) cp.getConstant(classIndex);
    1090            final String className = ((ConstantUtf8) cp.getConstant(cc.getNameIndex())).getBytes(); // Class Name in internal form
    1091            if (!validClassName(className)) {
    1092                throw new ClassConstraintException("Illegal class name '" + className + "' used by '" + tostring(obj) + "'.");
    1093            }
    1094
    1095            final String sig = ((ConstantUtf8) cp.getConstant(cnat.getSignatureIndex())).getBytes(); // Field or Method sig.(=descriptor)
    1096
    1097            try {
    1098                final Type t = Type.getReturnType(sig);
    1099                if (name.equals(Const.CONSTRUCTOR_NAME) && t != Type.VOID) {
    1100                    throw new ClassConstraintException("Instance initialization method must have VOID return type.");
    1101                }
    1102            } catch (final ClassFormatException cfe) {
    1103                throw new ClassConstraintException("Illegal descriptor (==signature) '" + sig + "' used by '" + tostring(obj) + "'.", cfe);
    1104            }
    1105        }
    1106
    1107    }
    1108
    1109    /**
    1110     * This class serves for finding out if a given JavaClass' ConstantPool references an Inner Class. The Java Virtual
    1111     * Machine Specification, Second Edition is not very precise about when an "InnerClasses" attribute has to appear.
    1112     * However, it states that there has to be exactly one InnerClasses attribute in the ClassFile structure if the constant
    1113     * pool of a class or interface refers to any class or interface "that is not a member of a package". Sun does not mean
    1114     * "member of the default package". In "Inner Classes Specification" they point out how a "bytecode name" is derived so
    1115     * one has to deduce what a class name of a class "that is not a member of a package" looks like: there is at least one
    1116     * character in the byte- code name that cannot be part of a legal Java Language Class name (and not equal to '/'). This
    1117     * assumption is wrong as the delimiter is '$' for which Character.isJavaIdentifierPart() == true. Hence, you really run
    1118     * into trouble if you have a toplevel class called "A$XXX" and another toplevel class called "A" with in inner class
    1119     * called "XXX". JustIce cannot repair this; please note that existing verifiers at this time even fail to detect
    1120     * missing InnerClasses attributes in pass 2.
    1121     */
    1122    private static final class InnerClassDetector extends EmptyVisitor {
    1123        private boolean hasInnerClass;
    1124        private final JavaClass jc;
    1125        private final ConstantPool cp;
    1126
    1127        /** Constructs an InnerClassDetector working on the JavaClass _jc. */
    1128        InnerClassDetector(final JavaClass javaClass) {
    1129            this.jc = javaClass;
    1130            this.cp = jc.getConstantPool();
    1131            new DescendingVisitor(jc, this).visit();
    1132        }
    1133
    1134        /**
    1135         * Returns if the JavaClass this InnerClassDetector is working on has an Inner Class reference in its constant pool.
    1136         *
    1137         * @return Whether this InnerClassDetector is working on has an Inner Class reference in its constant pool.
    1138         */
    1139        public boolean innerClassReferenced() {
    1140            return hasInnerClass;
    1141        }
    1142
    1143        /** This method casually visits ConstantClass references. */
    1144        @Override
    1145        public void visitConstantClass(final ConstantClass obj) {
    1146            final Constant c = cp.getConstant(obj.getNameIndex());
    1147            if (c instanceof ConstantUtf8) { // Ignore the case where it's not a ConstantUtf8 here, we'll find out later.
    1148                final String className = ((ConstantUtf8) c).getBytes();
    1149                if (className.startsWith(Utility.packageToPath(jc.getClassName()) + "$")) {
    1150                    hasInnerClass = true;
    1151                }
    1152            }
    1153        }
    1154    }
    1155
    1156    /**
    1157     * This method is here to save typing work and improve code readability.
    1158     */
    1159    private static String tostring(final Node n) {
    1160        return new StringRepresentation(n).toString();
    1161    }
    1162
    1163    /**
    1164     * This method returns true if and only if the supplied String represents a valid method name that may be referenced by
    1165     * ConstantMethodref objects.
    1166     */
    1167    private static boolean validClassMethodName(final String name) {
    1168        return validMethodName(name, false);
    1169    }
    1170
    1171    /**
    1172     * This method returns true if and only if the supplied String represents a valid Java class name.
    1173     */
    1174    private static boolean validClassName(final String name) {
    1175        /*
    1176         * TODO: implement. Are there any restrictions?
    1177         */
    1178        Objects.requireNonNull(name, "name");
    1179        return true;
    1180    }
    1181
    1182    /**
    1183     * This method returns true if and only if the supplied String represents a valid Java field name.
    1184     */
    1185    private static boolean validFieldName(final String name) {
    1186        // vmspec2 2.7, vmspec2 2.2
    1187        return validJavaIdentifier(name);
    1188    }
    1189
    1190    /**
    1191     * This method returns true if and only if the supplied String represents a valid Java interface method name that may be
    1192     * referenced by ConstantInterfaceMethodref objects.
    1193     */
    1194    private static boolean validInterfaceMethodName(final String name) {
    1195        // I guess we should assume special names forbidden here.
    1196        if (name.startsWith("<")) {
    1197            return false;
    1198        }
    1199        return validJavaLangMethodName(name);
    1200    }
    1201
    1202    /**
    1203     * This method returns true if and only if the supplied String represents a valid Java identifier (so-called simple or
    1204     * unqualified name).
    1205     */
    1206    private static boolean validJavaIdentifier(final String name) {
    1207        // vmspec2 2.7, vmspec2 2.2
    1208        if (name.isEmpty() || !Character.isJavaIdentifierStart(name.charAt(0))) {
    1209            return false;
    1210        }
    1211
    1212        for (int i = 1; i < name.length(); i++) {
    1213            if (!Character.isJavaIdentifierPart(name.charAt(i))) {
    1214                return false;
    1215            }
    1216        }
    1217        return true;
    1218    }
    1219
    1220    /**
    1221     * This method returns true if and only if the supplied String represents a valid Java programming language method name
    1222     * stored as a simple (non-qualified) name. Conforming to: The Java Virtual Machine Specification, Second Edition,
    1223     * �2.7, �2.7.1, �2.2.
    1224     */
    1225    private static boolean validJavaLangMethodName(final String name) {
    1226        return validJavaIdentifier(name);
    1227    }
    1228
    1229    /**
    1230     * This method returns true if and only if the supplied String represents a valid method name. This is basically the
    1231     * same as a valid identifier name in the Java programming language, but the special name for the instance
    1232     * initialization method is allowed and the special name for the class/interface initialization method may be allowed.
    1233     */
    1234    private static boolean validMethodName(final String name, final boolean allowStaticInit) {
    1235        if (validJavaLangMethodName(name)) {
    1236            return true;
    1237        }
    1238
    1239        if (allowStaticInit) {
    1240            return name.equals(Const.CONSTRUCTOR_NAME) || name.equals(Const.STATIC_INITIALIZER_NAME);
    1241        }
    1242        return name.equals(Const.CONSTRUCTOR_NAME);
    1243    }
    1244
    1245    /**
    1246     * The LocalVariableInfo instances used by Pass3bVerifier. localVariablesInfos[i] denotes the information for the local
    1247     * variables of method number i in the JavaClass this verifier operates on.
    1248     */
    1249    private LocalVariablesInfo[] localVariablesInfos;
    1250
    1251    /** The Verifier that created this. */
    1252    private final Verifier verifier;
    1253
    1254    /**
    1255     * Should only be instantiated by a Verifier.
    1256     *
    1257     * @see Verifier
    1258     */
    1259    public Pass2Verifier(final Verifier verifier) {
    1260        this.verifier = verifier;
    1261    }
    1262
    1263    /**
    1264     * Ensures that the constant pool entries satisfy the static constraints as described in The Java Virtual Machine
    1265     * Specification, 2nd Edition.
    1266     *
    1267     * @throws ClassConstraintException otherwise.
    1268     */
    1269    private void constantPoolEntriesSatisfyStaticConstraints() {
    1270        try {
    1271            // Most of the consistency is handled internally by BCEL; here
    1272            // we only have to verify if the indices of the constants point
    1273            // to constants of the appropriate type and such.
    1274            final JavaClass jc = Repository.lookupClass(verifier.getClassName());
    1275            new CPESSC_Visitor(jc); // constructor implicitly traverses jc
    1276
    1277        } catch (final ClassNotFoundException e) {
    1278            // FIXME: this might not be the best way to handle missing classes.
    1279            throw new AssertionViolatedException("Missing class: " + e, e);
    1280        }
    1281    }
    1282
    1283    /**
    1284     * Pass 2 is the pass where static properties of the class file are checked without looking into "Code" arrays of
    1285     * methods. This verification pass is usually invoked when a class is resolved; and it may be possible that this
    1286     * verification pass has to load in other classes such as superclasses or implemented interfaces. Therefore, Pass 1 is
    1287     * run on them.
    1288     * <p>
    1289     * Note that most referenced classes are <strong>not</strong> loaded in for verification or for an existence check by this pass;
    1290     * only the syntactical correctness of their names and descriptors (a.k.a. signatures) is checked.
    1291     * </p>
    1292     * <p>
    1293     * Very few checks that conceptually belong here are delayed until pass 3a in JustIce. JustIce does not only check for
    1294     * syntactical correctness but also for semantical sanity - therefore it needs access to the "Code" array of methods in
    1295     * a few cases. Please see the pass 3a documentation, too.
    1296     * </p>
    1297     *
    1298     * @see Pass3aVerifier
    1299     */
    1300    @Override
    1301    public VerificationResult do_verify() {
    1302        try {
    1303            final VerificationResult vr1 = verifier.doPass1();
    1304            if (vr1.equals(VerificationResult.VR_OK)) {
    1305
    1306                // For every method, we could have information about the local variables out of LocalVariableTable attributes of
    1307                // the Code attributes.
    1308                localVariablesInfos = new LocalVariablesInfo[Repository.lookupClass(verifier.getClassName()).getMethods().length];
    1309
    1310                VerificationResult vr = VerificationResult.VR_OK; // default.
    1311                try {
    1312                    constantPoolEntriesSatisfyStaticConstraints();
    1313                    fieldAndMethodRefsAreValid();
    1314                    everyClassHasAnAccessibleSuperclass();
    1315                    finalMethodsAreNotOverridden();
    1316                } catch (final ClassConstraintException cce) {
    1317                    vr = new VerificationResult(VerificationResult.VERIFIED_REJECTED, cce.getMessage());
    1318                }
    1319                return vr;
    1320            }
    1321            return VerificationResult.VR_NOTYET;
    1322
    1323        } catch (final ClassNotFoundException e) {
    1324            // FIXME: this might not be the best way to handle missing classes.
    1325            throw new AssertionViolatedException("Missing class: " + e, e);
    1326        }
    1327    }
    1328
    1329    /**
    1330     * Ensures that every class has a super class and that {@code final} classes are not subclassed. This means, the class
    1331     * this Pass2Verifier operates on has proper super classes (transitively) up to {@link Object}. The reason for really
    1332     * loading (and Pass1-verifying) all of those classes here is that we need them in Pass2 anyway to verify no final
    1333     * methods are overridden (that could be declared anywhere in the ancestor hierarchy).
    1334     *
    1335     * @throws ClassConstraintException otherwise.
    1336     */
    1337    private void everyClassHasAnAccessibleSuperclass() {
    1338        try {
    1339            final Set<String> hs = new HashSet<>(); // save class names to detect circular inheritance
    1340            JavaClass jc = Repository.lookupClass(verifier.getClassName());
    1341            int supidx = -1;
    1342
    1343            while (supidx != 0) {
    1344                supidx = jc.getSuperclassNameIndex();
    1345
    1346                if (supidx == 0) {
    1347                    if (jc != Repository.lookupClass(Type.OBJECT.getClassName())) {
    1348                        throw new ClassConstraintException(
    1349                            "Superclass of '" + jc.getClassName() + "' missing but not " + Type.OBJECT.getClassName() + " itself!");
    1350                    }
    1351                } else {
    1352                    final String supername = jc.getSuperclassName();
    1353                    if (!hs.add(supername)) { // If supername already is in the list
    1354                        throw new ClassConstraintException("Circular superclass hierarchy detected.");
    1355                    }
    1356                    final Verifier v = VerifierFactory.getVerifier(supername);
    1357                    final VerificationResult vr = v.doPass1();
    1358
    1359                    if (vr != VerificationResult.VR_OK) {
    1360                        throw new ClassConstraintException("Could not load in ancestor class '" + supername + "'.");
    1361                    }
    1362                    jc = Repository.lookupClass(supername);
    1363
    1364                    if (jc.isFinal()) {
    1365                        throw new ClassConstraintException(
    1366                            "Ancestor class '" + supername + "' has the FINAL access modifier and must therefore not be subclassed.");
    1367                    }
    1368                }
    1369            }
    1370
    1371        } catch (final ClassNotFoundException e) {
    1372            // FIXME: this might not be the best way to handle missing classes.
    1373            throw new AssertionViolatedException("Missing class: " + e, e);
    1374        }
    1375    }
    1376
    1377    /**
    1378     * Ensures that the ConstantCP-subclassed entries of the constant pool are valid. According to "Yellin: Low Level
    1379     * Security in Java", this method does not verify the existence of referenced entities (such as classes) but only the
    1380     * formal correctness (such as well-formed signatures). The visitXXX() methods throw ClassConstraintException instances
    1381     * otherwise. <B>Precondition: index-style cross referencing in the constant pool must be valid. Simply invoke
    1382     * constant_pool_entries_satisfy_static_constraints() before.</B>
    1383     *
    1384     * @throws ClassConstraintException otherwise.
    1385     * @see #constantPoolEntriesSatisfyStaticConstraints()
    1386     */
    1387    private void fieldAndMethodRefsAreValid() {
    1388        try {
    1389            final JavaClass jc = Repository.lookupClass(verifier.getClassName());
    1390            final DescendingVisitor v = new DescendingVisitor(jc, new FAMRAV_Visitor(jc));
    1391            v.visit();
    1392
    1393        } catch (final ClassNotFoundException e) {
    1394            // FIXME: this might not be the best way to handle missing classes.
    1395            throw new AssertionViolatedException("Missing class: " + e, e);
    1396        }
    1397    }
    1398
    1399    /**
    1400     * Ensures that {@code final} methods are not overridden. <B>Precondition to run this method:
    1401     * constant_pool_entries_satisfy_static_constraints() and every_class_has_an_accessible_superclass() have to be invoked
    1402     * before (in that order).</B>
    1403     *
    1404     * @throws ClassConstraintException otherwise.
    1405     * @see #constantPoolEntriesSatisfyStaticConstraints()
    1406     * @see #everyClassHasAnAccessibleSuperclass()
    1407     */
    1408    private void finalMethodsAreNotOverridden() {
    1409        try {
    1410            final Map<String, String> map = new HashMap<>();
    1411            JavaClass jc = Repository.lookupClass(verifier.getClassName());
    1412
    1413            int supidx = -1;
    1414            while (supidx != 0) {
    1415                supidx = jc.getSuperclassNameIndex();
    1416
    1417                final Method[] methods = jc.getMethods();
    1418                for (final Method method : methods) {
    1419                    final String nameAndSig = method.getName() + method.getSignature();
    1420
    1421                    if (map.containsKey(nameAndSig) && method.isFinal()) {
    1422                        if (!method.isPrivate()) {
    1423                            throw new ClassConstraintException("Method '" + nameAndSig + "' in class '" + map.get(nameAndSig)
    1424                                + "' overrides the final (not-overridable) definition in class '" + jc.getClassName() + "'.");
    1425                        }
    1426                        addMessage("Method '" + nameAndSig + "' in class '" + map.get(nameAndSig)
    1427                            + "' overrides the final (not-overridable) definition in class '" + jc.getClassName()
    1428                            + "'. This is okay, as the original definition was private; however this constraint leverage"
    1429                            + " was introduced by JLS 8.4.6 (not vmspec2) and the behavior of the Sun verifiers.");
    1430                    } else if (!method.isStatic()) { // static methods don't inherit
    1431                        map.put(nameAndSig, jc.getClassName());
    1432                    }
    1433                }
    1434
    1435                jc = Repository.lookupClass(jc.getSuperclassName());
    1436                // Well, for OBJECT this returns OBJECT so it works (could return anything but must not throw an Exception).
    1437            }
    1438
    1439        } catch (final ClassNotFoundException e) {
    1440            // FIXME: this might not be the best way to handle missing classes.
    1441            throw new AssertionViolatedException("Missing class: " + e, e);
    1442        }
    1443
    1444    }
    1445
    1446    /**
    1447     * Returns a LocalVariablesInfo object containing information about the usage of the local variables in the Code
    1448     * attribute of the said method or {@code null} if the class file this Pass2Verifier operates on could not be
    1449     * pass-2-verified correctly. The method number method_nr is the method you get using
    1450     * {@code Repository.lookupClass(myOwner.getClassname()).getMethods()[method_nr];}. You should not add own information.
    1451     * Leave that to JustIce.
    1452     */
    1453    public LocalVariablesInfo getLocalVariablesInfo(final int methodNr) {
    1454        if (verify() != VerificationResult.VR_OK) {
    1455            return null; // It's cached, don't worry.
    1456        }
    1457        if (methodNr < 0 || methodNr >= localVariablesInfos.length) {
    1458            throw new AssertionViolatedException("Method number out of range.");
    1459        }
    1460        return localVariablesInfos[methodNr];
    1461    }
    1462}