org.apache.bcel.classfile.LocalVariable Java Examples

/**
 * BCEL-295:
 */
public void testB295() throws Exception
{
    final JavaClass clazz = getTestClass(PACKAGE_BASE_NAME+".data.PLSETestClass2");
    final ClassGen cg = new ClassGen(clazz);
    final ConstantPoolGen pool = cg.getConstantPool();
    final Method m = cg.getMethodAt(1);  // 'main'
    final LocalVariableTable lvt = m.getLocalVariableTable();
    final LocalVariable lv = lvt.getLocalVariable(2, 4);  // 'i'
    //System.out.println(lv);
    final MethodGen mg = new MethodGen(m, cg.getClassName(), pool);
    final LocalVariableTable new_lvt = mg.getLocalVariableTable(mg.getConstantPool());
    final LocalVariable new_lv = new_lvt.getLocalVariable(2, 4);  // 'i'
    //System.out.println(new_lv);
    assertEquals("live range length", lv.getLength(), new_lv.getLength());
}
 

/**
 * returns the local variable at an index int the scope of PC
 *
 * @param lvt
 *            the local variable table
 * @param index
 *            the variable index
 * @param pc
 *            the PC where the variable is used
 */
public static LocalVariable getLocalVariableAtPC(@Nonnull LocalVariableTable lvt, int index, int pc) {
    int length = lvt.getTableLength();
    LocalVariable[] lvs = lvt.getLocalVariableTable();

    for (int i = 0; i < length; i++) {
        if (lvs[i].getIndex() == index) {
            int startPC = lvs[i].getStartPC();
            if ((pc >= startPC) && (pc < (startPC + lvs[i].getLength()))) {
                return lvs[i];
            }
        }
    }

    return null;
}
 

public static LocalVariableAnnotation getLocalVariableAnnotation(Method method, int local, int position1, int position2) {

        LocalVariableTable localVariableTable = method.getLocalVariableTable();
        String localName = UNKNOWN_NAME;
        if (localVariableTable != null) {
            LocalVariable lv1 = localVariableTable.getLocalVariable(local, position1);
            if (lv1 == null) {
                lv1 = localVariableTable.getLocalVariable(local, position2);
                position1 = position2;
            }
            if (lv1 != null) {
                localName = lv1.getName();
            }
        }
        LineNumberTable lineNumbers = method.getLineNumberTable();
        if (lineNumbers == null) {
            return new LocalVariableAnnotation(localName, local, position1);
        }
        int line = lineNumbers.getSourceLine(position1);
        return new LocalVariableAnnotation(localName, local, position1, line);
    }
 

/**
 * Gets LocalVariable object.
 *
 * This relies on that the instruction list has already been dumped to byte code or
 * or that the `setPositions' methods has been called for the instruction list.
 *
 * Note that due to the conversion from byte code offset to InstructionHandle,
 * it is impossible to tell the difference between a live range that ends BEFORE
 * the last insturction of the method or a live range that ends AFTER the last
 * instruction of the method.  Hence the liveToEnd flag to differentiate
 * between these two cases.
 *
 * @param cp constant pool
 */
public LocalVariable getLocalVariable( final ConstantPoolGen cp ) {
    int start_pc = 0;
    int length = 0;
    if ((start != null) && (end != null)) {
        start_pc = start.getPosition();
        length = end.getPosition() - start_pc;
        if ((end.getNext() == null) && liveToEnd) {
            length += end.getInstruction().getLength();
        }
    }
    final int name_index = cp.addUtf8(name);
    final int signature_index = cp.addUtf8(type.getSignature());
    return new LocalVariable(start_pc, length, name_index, signature_index, index, cp
            .getConstantPool(), origIndex);
}
 

private void updateLocalVariableTable(final LocalVariableTable a) {
    final LocalVariable[] lv = a.getLocalVariableTable();
    removeLocalVariables();
    for (final LocalVariable l : lv) {
        InstructionHandle start = il.findHandle(l.getStartPC());
        final InstructionHandle end = il.findHandle(l.getStartPC() + l.getLength());
        // Repair malformed handles
        if (null == start) {
            start = il.getStart();
        }
        // end == null => live to end of method
        // Since we are recreating the LocalVaraible, we must
        // propagate the orig_index to new copy.
        addLocalVariable(l.getName(), Type.getType(l.getSignature()), l
                .getIndex(), start, end, l.getOrigIndex());
    }
}
 

private void checkReferences()
{
   if (mLocalVariableTable != null) {
      for (int i = 0; i < mLocalVariableTable.getLength(); i++) {
           if (!mLocalVariableBitSet.get(i)) {
               final LocalVariable localVariable =
                   mLocalVariableTable.getLocalVariable(i);
               if (localVariable != null
                   && !localVariable.getName().equals("this"))
               {
                   log(0,
                       "unread.variable",
                       new Object[] {
                           mCurrentJavaClass.getClassName(),
                           mCurrentMethod.getName(),
                           localVariable.getName(),});
               }
           }
       }
   }
}
 

private void checkReferences()
{
   if (mLocalVariableTable != null) {
      for (int i = 0; i < mLocalVariableTable.getLength(); i++) {
           if (!mLocalVariableBitSet.get(i)) {
               final LocalVariable localVariable =
                   mLocalVariableTable.getLocalVariable(i);
               if (localVariable != null
                   && !localVariable.getName().equals("this"))
               {
                   log(0,
                       "unread.variable",
                       new Object[] {
                           mCurrentJavaClass.getClassName(),
                           mCurrentMethod.getName(),
                           localVariable.getName(),});
               }
           }
       }
   }
}
 

@CheckForNull
GenericObjectType getLocalVariable(int index, int pos) {
    if (genericLocalVariables == null || !genericLocalVariables.get(index)) {
        return null;
    }
    for (LocalVariable local : localTypeTable.getLocalVariableTypeTable()) {
        if (local.getIndex() == index && local.getStartPC() <= pos
                && pos < +local.getStartPC() + local.getLength()) {
            String signature = local.getSignature();
            if (signature.indexOf('<') < 0) {
                continue;
            }
            Type t;
            try {
                t = GenericUtilities.getType(signature);
                if (t instanceof GenericObjectType) {
                    return (GenericObjectType) t;
                }
            } catch (RuntimeException e) {
                AnalysisContext.logError("Bad signature " + signature
                        + " for " + local.getName(), e);

            }
            return null;
        }
    }
    return null;
}
 

@Override
public void visitLocalVariable(final LocalVariable obj) {
    // This does not represent an Attribute but is only
    // related to internal BCEL data representation.

    // see visitLocalVariableTable(LocalVariableTable)
}
 

private void adjustLocalVariableTypeTable(final LocalVariableTable lvt) {
    final LocalVariable[] lv = lvt.getLocalVariableTable();
    final LocalVariable[] lvg = localVariableTypeTable.getLocalVariableTypeTable();

    for (final LocalVariable element : lvg) {
        for (final LocalVariable l : lv) {
            if (element.getName().equals(l.getName()) && element.getIndex() == l.getOrigIndex()) {
                element.setLength(l.getLength());
                element.setStartPC(l.getStartPC());
                element.setIndex(l.getIndex());
                break;
            }
        }
    }
}
 

/**
 * @return `LocalVariableTable' attribute of all the local variables of this method.
 */
public LocalVariableTable getLocalVariableTable( final ConstantPoolGen cp ) {
    final LocalVariableGen[] lg = getLocalVariables();
    final int size = lg.length;
    final LocalVariable[] lv = new LocalVariable[size];
    for (int i = 0; i < size; i++) {
        lv[i] = lg[i].getLocalVariable(cp);
    }
    return new LocalVariableTable(cp.addUtf8("LocalVariableTable"), 2 + lv.length * 10, lv, cp
            .getConstantPool());
}
 

@Override
public void visitLocalVariableTable(LocalVariableTable obj) {
    super.visitLocalVariableTable(obj);
    LocalVariable[] local_variable_table = obj.getLocalVariableTable();
    for (LocalVariable aLocal_variable_table : local_variable_table) {
        aLocal_variable_table.accept(this);
    }
}
 

private void pushByLocalObjectLoad(DismantleBytecode dbc, int register) {
    Method m = dbc.getMethod();
    LocalVariableTable lvt = m.getLocalVariableTable();
    if (lvt != null) {
        LocalVariable lv = LVTHelper.getLocalVariableAtPC(lvt, register, dbc.getPC());
        if (lv != null) {
            String signature = lv.getSignature();
            pushByLocalLoad(signature, register);
            return;
        }
    }
    pushByLocalLoad("Ljava/lang/Object;", register);
}
 

@Override
public void visit(LocalVariable obj) {
    if (isReservedName(obj.getName())) {
        LocalVariableAnnotation var = new LocalVariableAnnotation(obj.getName(), obj.getIndex(), obj.getStartPC());
        SourceLineAnnotation source = SourceLineAnnotation.fromVisitedInstruction(getClassContext(), this, obj.getStartPC());
        BugInstance bug = new BugInstance(this, "NM_FUTURE_KEYWORD_USED_AS_IDENTIFIER", NORMAL_PRIORITY)
                .addClassAndMethod(this).add(var).add(source);
        bugReporter.reportBug(bug);
    }
}
 

@Override
public void visit(LocalVariableTable obj) {
    if (ENABLE_LOCALS) {
        if (staticMethod) {
            return;
        }

        LocalVariable[] vars = obj.getLocalVariableTable();
        // System.out.println("Num params = " + numParms);
        for (LocalVariable var : vars) {
            if (var.getIndex() < numParms) {
                continue;
            }
            String varName = var.getName();
            if ("serialVersionUID".equals(varName)) {
                continue;
            }
            Field f = classFields.get(varName);
            // System.out.println("Checking " + varName);
            // System.out.println(" got " + f);
            // TODO: we could distinguish between obscuring a field in the
            // same class
            // vs. obscuring a field in a superclass. Not sure how important
            // that is.
            if (f != null) {
                FieldAnnotation fa = FieldAnnotation.fromBCELField(getDottedClassName(), f);
                if (true || var.getStartPC() > 0) {
                    bugReporter.reportBug(new BugInstance(this, "MF_METHOD_MASKS_FIELD", LOW_PRIORITY)
                            .addClassAndMethod(this).addField(fa).addSourceLine(this, var.getStartPC() - 1));
                }
            }
        }
    }
    super.visit(obj);
}
 

@Override
public void visit(Code obj) {

    if (!getMethod().isPublic() && !getMethod().isProtected()) {
        return;
    }
    SignatureParser p = new SignatureParser(getMethodSig());
    LocalVariableTable t = obj.getLocalVariableTable();

    if (t == null) {
        return;
    }
    ParameterProperty property = new ParameterProperty();

    int index = getMethod().isStatic() ? 0 : 1;
    int parameterNumber = 0;
    for (Iterator<String> i = p.parameterSignatureIterator(); i.hasNext();) {
        String s = i.next();
        LocalVariable localVariable = t.getLocalVariable(index, 0);
        if (localVariable != null) {
            String name = localVariable.getName();
            if ("J".equals(s) && (name.toLowerCase().indexOf("instant") >= 0 || name.startsWith("date"))) {

                // System.out.println(getFullyQualifiedMethodName() + " " + s + " " + index + " " + name);
                property.setParamWithProperty(parameterNumber, true);
            }
        }
        if ("J".equals(s) || "D".equals(s)) {
            index += 2;
        } else {
            index += 1;
        }
        parameterNumber++;
    }
    if (!property.isEmpty()) {
        // System.out.println(getFullyQualifiedMethodName() + " " + property);
        database.setProperty(getMethodDescriptor(), property);
    }
}
 

@Override
public void sawOpcode(int seen) {
    switch (state) {
    case SEEN_NOTHING:
        if (seen == Const.ALOAD) {
            register = getRegisterOperand();
        } else if ((seen >= Const.ALOAD_0) && (seen <= Const.ALOAD_3)) {
            register = seen - Const.ALOAD_0;
        } else {
            return;
        }
        state = SEEN_ALOAD;
        break;

    case SEEN_ALOAD:
        try {
            if (seen == Const.INSTANCEOF) {
                LocalVariable lv = LVTHelper.getLocalVariableAtPC(varTable, register, getPC());
                if (lv != null) {
                    String objSignature = lv.getSignature();
                    if (objSignature.charAt(0) == 'L') {
                        objSignature = objSignature.substring(1, objSignature.length() - 1).replace('/', '.');
                        String clsSignature = getDottedClassConstantOperand();

                        if (clsSignature.charAt(0) != '[') {
                            if (org.apache.bcel.Repository.instanceOf(objSignature, clsSignature)) {
                                bugReporter.reportBug(new BugInstance(this, "SIO_SUPERFLUOUS_INSTANCEOF", LOW_PRIORITY)
                                        .addClassAndMethod(this).addSourceLine(this));
                            }
                        }
                    }
                }
            }
        } catch (ClassNotFoundException cnfe) {
            bugReporter.reportMissingClass(cnfe);
        }

        state = SEEN_NOTHING;
        break;
    default:
        break;
    }

}
 

@Override
public void sawOpcode(int seen) {
    if (iteratorBug != null) {
        if (isRegisterStore()) {
            LocalVariableTable lvt = getMethod().getLocalVariableTable();
            if (lvt != null) {
                LocalVariable localVariable = lvt.getLocalVariable(getRegisterOperand(), getNextPC());
                if (localVariable == null || localVariable.getName().endsWith("$")) {
                    // iterator() result is stored to the synthetic variable which has no name in LVT or name is suffixed with '$'
                    // Looks like it's for-each cycle like for(Object obj : this)
                    // Do not report such case
                    iteratorBug = null;
                }
            }
        }
        if (iteratorBug != null) {
            bugAccumulator.accumulateBug(iteratorBug, this);
        }
        iteratorBug = null;
    }
    if (seen != Const.INVOKEVIRTUAL) {
        return;
    }
    if (!getClassName().equals(getClassConstantOperand())) {
        return;
    }
    XMethod invokedMethod = XFactory.createXMethod(getDottedClassConstantOperand(), getNameConstantOperand(),
            getSigConstantOperand(), false);
    if (invokedMethod.isResolved() && invokedMethod.getClassName().equals(getDottedClassConstantOperand())
            || invokedMethod.isSynthetic()) {
        return;
    }
    if (getStack().getStackItem(getNumberArguments(getSigConstantOperand())).getRegisterNumber() != 0) {
        // called not for this object
        return;
    }
    // method is inherited
    String possibleTargetClass = getDottedClassName();
    String superClassName = getDottedSuperclassName();
    while (true) {
        int i = possibleTargetClass.lastIndexOf('$');
        if (i <= 0) {
            break;
        }
        possibleTargetClass = possibleTargetClass.substring(0, i);
        if (possibleTargetClass.equals(superClassName)) {
            break;
        }
        XMethod alternativeMethod = XFactory.createXMethod(possibleTargetClass, getNameConstantOperand(),
                getSigConstantOperand(), false);
        if (alternativeMethod.isResolved() && alternativeMethod.getClassName().equals(possibleTargetClass)) {
            String targetPackage = invokedMethod.getPackageName();
            String alternativePackage = alternativeMethod.getPackageName();
            int priority = HIGH_PRIORITY;
            if (targetPackage.equals(alternativePackage)) {
                priority++;
            }
            if (targetPackage.startsWith("javax.swing") || targetPackage.startsWith("java.awt")) {
                priority += 2;
            }
            if (invokedMethod.getName().equals(getMethodName())) {
                priority++;
            }

            BugInstance bug = new BugInstance(this, "IA_AMBIGUOUS_INVOCATION_OF_INHERITED_OR_OUTER_METHOD", priority)
                    .addClassAndMethod(this).addMethod(invokedMethod).describe("METHOD_INHERITED")
                    .addMethod(alternativeMethod).describe("METHOD_ALTERNATIVE_TARGET");
            if (invokedMethod.getName().equals("iterator") && invokedMethod.getSignature().equals("()Ljava/util/Iterator;")
                    && Subtypes2.instanceOf(getDottedClassName(), "java.lang.Iterable")) {
                iteratorBug = bug;
            } else {
                bugAccumulator.accumulateBug(bug, this);
            }
            break;
        }
    }
}
 

@Override
public void visitLocalVariable(LocalVariable obj) {
    visit(obj);
}
 

@Override
public void visitLocalVariable(final LocalVariable obj) {
    tostring = toString(obj);
}
 

@Override
public void visitLocalVariable(final LocalVariable obj)
{
    localVariableCount++;
}
 

public void visit(LocalVariable obj) {
}