/*
* FindBugs - Find Bugs in Java programs
* Copyright (C) 2003-2007 University of Maryland
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package edu.umd.cs.findbugs.ba.vna;
import javax.annotation.CheckForNull;
import javax.annotation.Nonnull;
import org.apache.bcel.classfile.Method;
import org.apache.bcel.generic.ACONST_NULL;
import org.apache.bcel.generic.InstructionHandle;
import edu.umd.cs.findbugs.BugAnnotation;
import edu.umd.cs.findbugs.FieldAnnotation;
import edu.umd.cs.findbugs.LocalVariableAnnotation;
import edu.umd.cs.findbugs.StringAnnotation;
import edu.umd.cs.findbugs.ba.CFGBuilderException;
import edu.umd.cs.findbugs.ba.ClassContext;
import edu.umd.cs.findbugs.ba.DataflowAnalysisException;
import edu.umd.cs.findbugs.ba.Location;
import edu.umd.cs.findbugs.ba.XField;
/**
* Helper methods to find out information about the source of the value
* represented by a given ValueNumber.
*
* @author Bill Pugh
* @author David Hovemeyer
*/
public abstract class ValueNumberSourceInfo {
/**
* @param method
* @param location
* @param valueNumber
* @param vnaFrame
* @param partialRole
* TODO
* @return the annotation
*/
public static @CheckForNull
BugAnnotation findAnnotationFromValueNumber(Method method, Location location, ValueNumber valueNumber,
ValueNumberFrame vnaFrame, @CheckForNull String partialRole) {
if (location.getHandle().getInstruction() instanceof ACONST_NULL) {
StringAnnotation nullConstant = new StringAnnotation("null");
nullConstant.setDescription(StringAnnotation.STRING_NONSTRING_CONSTANT_ROLE);
return nullConstant;
}
LocalVariableAnnotation ann = ValueNumberSourceInfo.findLocalAnnotationFromValueNumber(method, location, valueNumber,
vnaFrame);
if (ann != null && partialRole != null) {
ann.setDescription("LOCAL_VARIABLE_" + partialRole);
}
if (ann != null && ann.isSignificant()) {
return ann;
}
FieldAnnotation field = ValueNumberSourceInfo.findFieldAnnotationFromValueNumber(method, location, valueNumber, vnaFrame);
if (field != null) {
if (partialRole != null) {
field.setDescription("FIELD_" + partialRole);
}
return field;
}
if (ann != null) {
return ann;
}
return null;
}
/**
* @param method
* @param location
* @param valueNumber
* @param vnaFrame
* @param partialRole
* TODO
* @return the annotation
*/
public static @Nonnull
BugAnnotation findRequiredAnnotationFromValueNumber(Method method, Location location, ValueNumber valueNumber,
ValueNumberFrame vnaFrame, @CheckForNull String partialRole) {
BugAnnotation result = findAnnotationFromValueNumber(method, location, valueNumber, vnaFrame, partialRole);
if (result != null) {
return result;
}
return new LocalVariableAnnotation("?", -1, location.getHandle().getPosition());
}
public static LocalVariableAnnotation findLocalAnnotationFromValueNumber(Method method, Location location,
ValueNumber valueNumber, ValueNumberFrame vnaFrame) {
if (vnaFrame == null || vnaFrame.isBottom() || vnaFrame.isTop()) {
return null;
}
LocalVariableAnnotation localAnnotation = null;
for (int i = 0; i < vnaFrame.getNumLocals(); i++) {
if (valueNumber.equals(vnaFrame.getValue(i))) {
InstructionHandle handle = location.getHandle();
InstructionHandle prev = handle.getPrev();
if (prev == null) {
continue;
}
int position1 = prev.getPosition();
int position2 = handle.getPosition();
localAnnotation = LocalVariableAnnotation.getLocalVariableAnnotation(method, i, position1, position2);
if (localAnnotation != null) {
return localAnnotation;
}
}
}
return null;
}
public static FieldAnnotation findFieldAnnotationFromValueNumber(Method method, Location location, ValueNumber valueNumber,
ValueNumberFrame vnaFrame) {
XField field = ValueNumberSourceInfo.findXFieldFromValueNumber(method, location, valueNumber, vnaFrame);
if (field == null) {
return null;
}
return FieldAnnotation.fromXField(field);
}
public static XField findXFieldFromValueNumber(Method method, Location location, ValueNumber valueNumber,
ValueNumberFrame vnaFrame) {
if (vnaFrame == null || vnaFrame.isBottom() || vnaFrame.isTop()) {
return null;
}
AvailableLoad load = vnaFrame.getLoad(valueNumber);
if (load != null) {
return load.getField();
}
return null;
}
/**
* @param classContext
* @param method
* @param location
* @param stackPos
* @throws DataflowAnalysisException
* @throws CFGBuilderException
*/
static @CheckForNull
public BugAnnotation getFromValueNumber(ClassContext classContext, Method method, Location location, int stackPos)
throws DataflowAnalysisException, CFGBuilderException {
ValueNumberFrame vnaFrame = classContext.getValueNumberDataflow(method).getFactAtLocation(location);
if (!vnaFrame.isValid()) {
return null;
}
ValueNumber valueNumber = vnaFrame.getStackValue(stackPos);
if (valueNumber.hasFlag(ValueNumber.CONSTANT_CLASS_OBJECT)) {
return null;
}
BugAnnotation variableAnnotation = findAnnotationFromValueNumber(method, location, valueNumber, vnaFrame, "VALUE_OF");
return variableAnnotation;
}
}