/**
   * Compare to see if the argument <code>argType</code> passed to the method matches the type of
   * the corresponding parameter. The simplest case is when both are equal.
   *
   * <p>This is a conservative comparison - returns true if it cannot decide. If the parameter type
   * is a type variable (e.g. <code>T</code>) then we don't know enough (yet) to decide if they do
   * not match so return true.
   *
   * @param ignoreBaseType TODO
   */
  private IncompatibleTypes compareTypes(
      Type expectedType, Type actualType, boolean ignoreBaseType) {
    // XXX equality not implemented for GenericObjectType
    // if (parmType.equals(argType)) return true;
    if (expectedType == actualType) return IncompatibleTypes.SEEMS_OK;
    // Compare type signatures instead
    String expectedString = GenericUtilities.getString(expectedType);
    String actualString = GenericUtilities.getString(actualType);
    if (expectedString.equals(actualString)) return IncompatibleTypes.SEEMS_OK;

    if (expectedType.equals(Type.OBJECT)) return IncompatibleTypes.SEEMS_OK;
    // if either type is java.lang.Object, then automatically true!
    // again compare strings...

    String objString = GenericUtilities.getString(Type.OBJECT);

    if (expectedString.equals(objString)) {
      return IncompatibleTypes.SEEMS_OK;
    }

    // get a category for each type
    TypeCategory expectedCat = GenericUtilities.getTypeCategory(expectedType);
    TypeCategory argCat = GenericUtilities.getTypeCategory(actualType);
    if (actualString.equals(objString) && expectedCat == TypeCategory.TYPE_VARIABLE) {
      return IncompatibleTypes.SEEMS_OK;
    }
    if (ignoreBaseType) {
      if (expectedCat == TypeCategory.PARAMETERIZED && argCat == TypeCategory.PARAMETERIZED) {
        GenericObjectType parmGeneric = (GenericObjectType) expectedType;
        GenericObjectType argGeneric = (GenericObjectType) actualType;
        return compareTypeParameters(parmGeneric, argGeneric);
      }
      return IncompatibleTypes.SEEMS_OK;
    }

    if (actualType.equals(Type.OBJECT) && expectedCat == TypeCategory.ARRAY_TYPE)
      return IncompatibleTypes.ARRAY_AND_OBJECT;

    // -~- plain objects are easy
    if (expectedCat == TypeCategory.PLAIN_OBJECT_TYPE && argCat == TypeCategory.PLAIN_OBJECT_TYPE)
      return IncompatibleTypes.getPriorityForAssumingCompatible(expectedType, actualType, false);

    if (expectedCat == TypeCategory.PARAMETERIZED && argCat == TypeCategory.PLAIN_OBJECT_TYPE)
      return IncompatibleTypes.getPriorityForAssumingCompatible(
          (GenericObjectType) expectedType, actualType);
    if (expectedCat == TypeCategory.PLAIN_OBJECT_TYPE && argCat == TypeCategory.PARAMETERIZED)
      return IncompatibleTypes.getPriorityForAssumingCompatible(
          (GenericObjectType) actualType, expectedType);

    // -~- parmType is: "? extends Another Type" OR "? super Another Type"
    if (expectedCat == TypeCategory.WILDCARD_EXTENDS || expectedCat == TypeCategory.WILDCARD_SUPER)
      return compareTypes(
          ((GenericObjectType) expectedType).getExtension(), actualType, ignoreBaseType);

    // -~- Not handling type variables
    if (expectedCat == TypeCategory.TYPE_VARIABLE || argCat == TypeCategory.TYPE_VARIABLE)
      return IncompatibleTypes.SEEMS_OK;

    // -~- Array Types: compare dimensions, then base type
    if (expectedCat == TypeCategory.ARRAY_TYPE && argCat == TypeCategory.ARRAY_TYPE) {
      ArrayType parmArray = (ArrayType) expectedType;
      ArrayType argArray = (ArrayType) actualType;

      if (parmArray.getDimensions() != argArray.getDimensions())
        return IncompatibleTypes.ARRAY_AND_NON_ARRAY;

      return compareTypes(parmArray.getBasicType(), argArray.getBasicType(), ignoreBaseType);
    }
    // If one is an Array Type and the other is not, then they
    // are incompatible. (We already know neither is java.lang.Object)
    if (expectedCat == TypeCategory.ARRAY_TYPE ^ argCat == TypeCategory.ARRAY_TYPE) {
      return IncompatibleTypes.ARRAY_AND_NON_ARRAY;
    }

    // -~- Parameter Types: compare base type then parameters
    if (expectedCat == TypeCategory.PARAMETERIZED && argCat == TypeCategory.PARAMETERIZED) {
      GenericObjectType parmGeneric = (GenericObjectType) expectedType;
      GenericObjectType argGeneric = (GenericObjectType) actualType;

      // base types should be related
      {
        IncompatibleTypes result =
            compareTypes(parmGeneric.getObjectType(), argGeneric.getObjectType(), ignoreBaseType);
        if (!result.equals(IncompatibleTypes.SEEMS_OK)) return result;
      }
      return compareTypeParameters(parmGeneric, argGeneric);

      // XXX More to come
    }
    // If one is a Parameter Type and the other is not, then they
    // are incompatible. (We already know neither is java.lang.Object)
    if (false) {
      // not true. Consider class Foo extends ArrayList<String>
      if (expectedCat == TypeCategory.PARAMETERIZED ^ argCat == TypeCategory.PARAMETERIZED) {
        return IncompatibleTypes.SEEMS_OK; // fix this when we know what
        // we are doing here
      }
    }

    // -~- Wildcard e.g. List<*>.contains(...)
    if (expectedCat == TypeCategory.WILDCARD) // No Way to know
    return IncompatibleTypes.SEEMS_OK;

    // -~- Non Reference types
    // if ( parmCat == TypeCategory.NON_REFERENCE_TYPE ||
    // argCat == TypeCategory.NON_REFERENCE_TYPE )
    if (expectedType instanceof BasicType || actualType instanceof BasicType) {
      // this should not be possible, compiler will complain (pre 1.5)
      // or autobox primitive types (1.5 +)
      throw new IllegalArgumentException(
          "checking for compatibility of " + expectedType + " with " + actualType);
    }

    return IncompatibleTypes.SEEMS_OK;
  }
  private void analyzeMethod(ClassContext classContext, Method method)
      throws CFGBuilderException, DataflowAnalysisException {
    if (isSynthetic(method) || !prescreen(classContext, method)) return;
    XMethod xmethod = XFactory.createXMethod(classContext.getJavaClass(), method);
    if (xmethod.isSynthetic()) return;

    BugAccumulator accumulator = new BugAccumulator(bugReporter);

    CFG cfg = classContext.getCFG(method);
    TypeDataflow typeDataflow = classContext.getTypeDataflow(method);
    ValueNumberDataflow vnDataflow = classContext.getValueNumberDataflow(method);

    ConstantPoolGen cpg = classContext.getConstantPoolGen();
    MethodGen methodGen = classContext.getMethodGen(method);
    if (methodGen == null) return;
    String fullMethodName = methodGen.getClassName() + "." + methodGen.getName();

    String sourceFile = classContext.getJavaClass().getSourceFileName();
    if (DEBUG) {
      System.out.println("\n" + fullMethodName);
    }

    // Process each instruction
    for (Iterator<Location> iter = cfg.locationIterator(); iter.hasNext(); ) {
      Location location = iter.next();
      InstructionHandle handle = location.getHandle();
      Instruction ins = handle.getInstruction();

      // Only consider invoke instructions
      if (!(ins instanceof InvokeInstruction)) continue;

      InvokeInstruction inv = (InvokeInstruction) ins;

      XMethod invokedMethod = XFactory.createXMethod(inv, cpg);

      String invokedMethodName = invokedMethod.getName();
      String argSignature = invokedMethod.getSignature();
      argSignature = argSignature.substring(0, argSignature.indexOf(')') + 1);
      String call = invokedMethodName + argSignature;
      SignatureParser sigParser = new SignatureParser(inv.getSignature(cpg));

      Collection<Info> collection = callMap.get(call);
      if (!callMap.containsKey(call)) continue;
      for (Info info : collection) {
        Subtypes2 subtypes2 = AnalysisContext.currentAnalysisContext().getSubtypes2();
        if (DEBUG)
          System.out.println(
              "at "
                  + handle.getPosition()
                  + " Checking call to "
                  + info.interfaceForCall
                  + " : "
                  + invokedMethod);
        try {
          if (!subtypes2.isSubtype(invokedMethod.getClassDescriptor(), info.interfaceForCall))
            continue;
        } catch (ClassNotFoundException e) {
          if (info.interfaceForCall.getClassName().equals("java/util/Collection")
              && invokedMethod.getClassName().equals("com.google.common.collect.Multiset")) {
            assert true;
            // we know this is OK without needing to find definition of Multiset
          } else {
            AnalysisContext.reportMissingClass(e);
            continue;
          }
        }

        boolean allMethod;

        int typeArgument;
        if (info.typeIndex >= 0) {
          allMethod = false;
          typeArgument = info.typeIndex;
        } else {
          allMethod = true;
          typeArgument = -(1 + info.typeIndex);
        }
        int pos = info.argumentIndex;

        int lhsPos;
        if (inv instanceof INVOKESTATIC) lhsPos = sigParser.getSlotsFromTopOfStackForParameter(0);
        else lhsPos = sigParser.getTotalArgumentSize();

        int stackPos = sigParser.getSlotsFromTopOfStackForParameter(pos);

        TypeFrame frame = typeDataflow.getFactAtLocation(location);
        if (!frame.isValid()) {
          // This basic block is probably dead
          continue;
        }

        Type operandType = frame.getStackValue(stackPos);
        if (operandType.equals(TopType.instance())) {
          // unreachable
          continue;
        }

        if (operandType.equals(NullType.instance())) {
          // ignore
          continue;
        }

        ValueNumberFrame vnFrame = vnDataflow.getFactAtLocation(location);

        if (!vnFrame.isValid()) {
          AnalysisContext.logError("Invalid value number frame in " + xmethod);
          continue;
        }

        ValueNumber objectVN = vnFrame.getStackValue(lhsPos);
        ValueNumber argVN = vnFrame.getStackValue(stackPos);

        if (objectVN.equals(argVN)) {
          String bugPattern = "DMI_COLLECTIONS_SHOULD_NOT_CONTAIN_THEMSELVES";
          int priority = HIGH_PRIORITY;
          if (invokedMethodName.equals("removeAll")) {
            bugPattern = "DMI_USING_REMOVEALL_TO_CLEAR_COLLECTION";
            priority = NORMAL_PRIORITY;
          } else if (invokedMethodName.endsWith("All")) {
            bugPattern = "DMI_VACUOUS_SELF_COLLECTION_CALL";
            priority = NORMAL_PRIORITY;
          }
          if (invokedMethodName.startsWith("contains")) {
            InstructionHandle next = handle.getNext();
            if (next != null) {
              Instruction nextIns = next.getInstruction();

              if (nextIns instanceof InvokeInstruction) {
                XMethod nextMethod = XFactory.createXMethod((InvokeInstruction) nextIns, cpg);
                if (nextMethod.getName().equals("assertFalse")) continue;
              }
            }
          }
          accumulator.accumulateBug(
              new BugInstance(this, bugPattern, priority)
                  .addClassAndMethod(methodGen, sourceFile)
                  .addCalledMethod(methodGen, (InvokeInstruction) ins)
                  .addOptionalAnnotation(
                      ValueNumberSourceInfo.findAnnotationFromValueNumber(
                          method, location, objectVN, vnFrame, "INVOKED_ON")),
              SourceLineAnnotation.fromVisitedInstruction(
                  classContext, methodGen, sourceFile, handle));
        }

        // Only consider generic...
        Type objectType = frame.getStackValue(lhsPos);
        if (!(objectType instanceof GenericObjectType)) continue;

        GenericObjectType operand = (GenericObjectType) objectType;

        int expectedTypeParameters = 1;
        String simpleName = info.interfaceForCall.getSimpleName();
        if (simpleName.toLowerCase().endsWith("map") || simpleName.equals("Hashtable"))
          expectedTypeParameters = 2;
        else if (simpleName.equals("Table")) expectedTypeParameters = 3;

        // ... containers
        if (!operand.hasParameters()) continue;
        if (operand.getNumParameters() != expectedTypeParameters) continue;
        ClassDescriptor operandClass = DescriptorFactory.getClassDescriptor(operand);
        if (!isGenericCollection(operandClass)) continue;

        if (expectedTypeParameters == 2
            && Subtypes2.instanceOf(operandClass, Map.class)
            && !TypeFrameModelingVisitor.isStraightGenericMap(operandClass)) continue;
        Type expectedType;
        if (allMethod) expectedType = operand;
        else expectedType = operand.getParameterAt(typeArgument);
        Type actualType = frame.getStackValue(stackPos);
        Type equalsType = actualType;
        if (allMethod) {
          if (!(actualType instanceof GenericObjectType)) {
            continue;
          }
          equalsType = ((GenericObjectType) actualType).getParameterAt(typeArgument);
        }

        IncompatibleTypes matchResult = compareTypes(expectedType, actualType, allMethod);

        boolean parmIsObject = expectedType.getSignature().equals("Ljava/lang/Object;");
        boolean selfOperation = !allMethod && operand.equals(actualType) && !parmIsObject;
        if (!allMethod && !parmIsObject && actualType instanceof GenericObjectType) {

          GenericObjectType p2 = (GenericObjectType) actualType;
          List<? extends ReferenceType> parameters = p2.getParameters();
          if (parameters != null && parameters.equals(operand.getParameters()))
            selfOperation = true;
        }

        if (!selfOperation
            && (matchResult == IncompatibleTypes.SEEMS_OK
                || matchResult.getPriority() == Priorities.IGNORE_PRIORITY)) continue;

        if (invokedMethodName.startsWith("contains") || invokedMethodName.equals("remove")) {
          InstructionHandle next = handle.getNext();
          if (next != null) {
            Instruction nextIns = next.getInstruction();

            if (nextIns instanceof InvokeInstruction) {
              XMethod nextMethod = XFactory.createXMethod((InvokeInstruction) nextIns, cpg);
              if (nextMethod.getName().equals("assertFalse")) continue;
            }
          }
        } else if (invokedMethodName.equals("get") || invokedMethodName.equals("remove")) {
          InstructionHandle next = handle.getNext();
          if (next != null) {
            Instruction nextIns = next.getInstruction();

            if (nextIns instanceof InvokeInstruction) {
              XMethod nextMethod = XFactory.createXMethod((InvokeInstruction) nextIns, cpg);
              if (nextMethod.getName().equals("assertNull")) continue;
            }
          }
        }
        boolean noisy = false;
        if (invokedMethodName.equals("get")) {
          UnconditionalValueDerefDataflow unconditionalValueDerefDataflow =
              classContext.getUnconditionalValueDerefDataflow(method);

          UnconditionalValueDerefSet unconditionalDeref =
              unconditionalValueDerefDataflow.getFactAtLocation(location);
          ValueNumberFrame vnAfter = vnDataflow.getFactAfterLocation(location);
          ValueNumber top = vnAfter.getTopValue();
          noisy =
              unconditionalDeref.getValueNumbersThatAreUnconditionallyDereferenced().contains(top);
        }
        // Prepare bug report
        SourceLineAnnotation sourceLineAnnotation =
            SourceLineAnnotation.fromVisitedInstruction(
                classContext, methodGen, sourceFile, handle);

        // Report a bug that mentions each of the failed arguments in
        // matches

        if (expectedType instanceof GenericObjectType)
          expectedType = ((GenericObjectType) expectedType).getUpperBound();

        int priority = matchResult.getPriority();
        if (!operandClass.getClassName().startsWith("java/util")
            && priority == Priorities.HIGH_PRIORITY)
          priority = Math.max(priority, Priorities.NORMAL_PRIORITY);
        if (TestCaseDetector.likelyTestCase(xmethod))
          priority = Math.max(priority, Priorities.NORMAL_PRIORITY);
        else if (selfOperation) priority = Priorities.HIGH_PRIORITY;
        ClassDescriptor expectedClassDescriptor =
            DescriptorFactory.createClassOrObjectDescriptorFromSignature(
                expectedType.getSignature());
        ClassDescriptor actualClassDescriptor =
            DescriptorFactory.createClassOrObjectDescriptorFromSignature(equalsType.getSignature());
        ClassSummary classSummary = AnalysisContext.currentAnalysisContext().getClassSummary();
        Set<XMethod> targets = null;
        try {
          targets =
              Hierarchy2.resolveVirtualMethodCallTargets(
                  actualClassDescriptor, "equals", "(Ljava/lang/Object;)Z", false, false);
          boolean allOk = targets.size() > 0;
          for (XMethod m2 : targets)
            if (!classSummary.mightBeEqualTo(m2.getClassDescriptor(), expectedClassDescriptor))
              allOk = false;
          if (allOk) priority += 2;
        } catch (ClassNotFoundException e) {
          AnalysisContext.reportMissingClass(e);
        }
        String bugPattern = "GC_UNRELATED_TYPES";

        BugInstance bug =
            new BugInstance(this, bugPattern, priority)
                .addClassAndMethod(methodGen, sourceFile)
                .addFoundAndExpectedType(actualType, expectedType)
                .addCalledMethod(methodGen, (InvokeInstruction) ins)
                .addOptionalAnnotation(
                    ValueNumberSourceInfo.findAnnotationFromValueNumber(
                        method, location, objectVN, vnFrame, "INVOKED_ON"))
                .addOptionalAnnotation(
                    ValueNumberSourceInfo.findAnnotationFromValueNumber(
                        method, location, argVN, vnFrame, "ARGUMENT"))
                .addEqualsMethodUsed(targets);
        if (noisy) {
          WarningPropertySet<WarningProperty> propertySet =
              new WarningPropertySet<WarningProperty>();

          propertySet.addProperty(GeneralWarningProperty.NOISY_BUG);
          propertySet.decorateBugInstance(bug);
        }
        accumulator.accumulateBug(bug, sourceLineAnnotation);
      }
    }
    accumulator.reportAccumulatedBugs();
  }