Package edu.umd.cs.findbugs.detect

Class FindInconsistentSync2

java.lang.Object

edu.umd.cs.findbugs.detect.FindInconsistentSync2

All Implemented Interfaces:

Detector, Priorities

public class FindInconsistentSync2
extends java.lang.Object
implements Detector

Find instance fields which are sometimes accessed (read or written) with the receiver lock held and sometimes without. These are candidates to be data races.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	FindInconsistentSync2.FieldAccess
private static class	FindInconsistentSync2.FieldStats	The access statistics for a field.

Field Summary

Fields

Modifier and Type	Field	Description
private static boolean	ADJUST_SUBCLASS_ACCESSES
private BugReporter	bugReporter
private static boolean	DEBUG
private static boolean	EVAL
private static ClassDescriptor	javaxServlet
private static int	LOCKED
private static int	MIN_SYNC_PERCENT	Minimum percent of unbiased field accesses that must be synchronized in order to report a field as inconsistently synchronized.
private static int	NULLCHECK
private static int	NULLCHECK_LOCKED
private static int	NULLCHECK_UNLOCKED
private static int	READ
private static int	READ_LOCKED
private static int	READ_UNLOCKED
private static ClassDescriptor	singleThreadedServlet
private java.util.Map<XField,FindInconsistentSync2.FieldStats>	statMap
private static boolean	SYNC_ACCESS
private static int	UNLOCKED
private static double	UNSYNC_FACTOR	Factor which the biased number of unsynchronized accesses is multiplied by.
private static int	WRITE
private static double	WRITE_BIAS	Bias that writes are given with respect to reads.
private static int	WRITE_LOCKED
private static int	WRITE_UNLOCKED

Fields inherited from interface edu.umd.cs.findbugs.Priorities

EXP_PRIORITY, HIGH_PRIORITY, IGNORE_PRIORITY, LOW_PRIORITY, NORMAL_PRIORITY

Constructor Summary

Constructors

Constructor	Description
FindInconsistentSync2(BugReporter bugReporter)

Method Summary

Modifier and Type	Method	Description
private void	analyzeMethod(ClassContext classContext, org.apache.bcel.classfile.Method method, java.util.Set<org.apache.bcel.classfile.Method> lockedMethodSet)
private static java.util.Set<org.apache.bcel.classfile.Method>	findLockedMethods(ClassContext classContext, SelfCalls selfCalls, java.util.Set<CallSite> obviouslyLockedSites)	Find methods that appear to always be called from a locked context.
private static java.util.Set<org.apache.bcel.classfile.Method>	findNotUnlockedMethods(ClassContext classContext, SelfCalls selfCalls, java.util.Set<CallSite> obviouslyLockedSites)	Find methods that appear to never be called from an unlocked context We assume that nonpublic methods will only be called from within the class, which is not really a valid assumption.
private static java.util.Set<CallSite>	findObviouslyLockedCallSites(ClassContext classContext, SelfCalls selfCalls)	Find all self-call sites that are obviously locked.
private FindInconsistentSync2.FieldStats	getStats(XField field)	Get the access statistics for given field.
private static boolean	isConstructor(java.lang.String methodName)
static boolean	isGetterMethod(ClassContext classContext, org.apache.bcel.classfile.Method method)	Determine whether or not the given method is a getter method.
static boolean	isServletField(XField field)
void	report()	This method is called after all classes to be visited.
void	visitClassContext(ClassContext classContext)	Visit the ClassContext for a class which should be analyzed for instances of bug patterns.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEBUG

private static final boolean DEBUG

SYNC_ACCESS

private static final boolean SYNC_ACCESS

See Also:

Constant Field Values

ADJUST_SUBCLASS_ACCESSES

private static final boolean ADJUST_SUBCLASS_ACCESSES

EVAL

private static final boolean EVAL

MIN_SYNC_PERCENT

private static final int MIN_SYNC_PERCENT

Minimum percent of unbiased field accesses that must be synchronized in order to report a field as inconsistently synchronized. This is meant to distinguish incidental synchronization from intentional synchronization.

WRITE_BIAS

private static final double WRITE_BIAS

Bias that writes are given with respect to reads. The idea is that this should be above 1.0, because unsynchronized writes are more dangerous than unsynchronized reads.

UNSYNC_FACTOR

private static final double UNSYNC_FACTOR

Factor which the biased number of unsynchronized accesses is multiplied by. I.e., for factor f, if nUnsync is the biased number of unsynchronized accesses, and nSync is the biased number of synchronized accesses, and

      f(nUnsync) > nSync
 

then we report a bug. Default value is 2.0, which means that we report a bug if more than 1/3 of accesses are unsynchronized.

Note that MIN_SYNC_PERCENT also influences whether we report a bug: it specifies the minimum unbiased percentage of synchronized accesses.

UNLOCKED

private static final int UNLOCKED

See Also:

Constant Field Values

LOCKED

private static final int LOCKED

See Also:

Constant Field Values

READ

private static final int READ

See Also:

Constant Field Values

WRITE

private static final int WRITE

See Also:

Constant Field Values

NULLCHECK

private static final int NULLCHECK

See Also:

Constant Field Values

READ_UNLOCKED

private static final int READ_UNLOCKED

See Also:

Constant Field Values

WRITE_UNLOCKED

private static final int WRITE_UNLOCKED

See Also:

Constant Field Values

NULLCHECK_UNLOCKED

private static final int NULLCHECK_UNLOCKED

See Also:

Constant Field Values

READ_LOCKED

private static final int READ_LOCKED

See Also:

Constant Field Values

WRITE_LOCKED

private static final int WRITE_LOCKED

See Also:

Constant Field Values

NULLCHECK_LOCKED

private static final int NULLCHECK_LOCKED

See Also:

Constant Field Values

javaxServlet

private static ClassDescriptor javaxServlet

singleThreadedServlet

private static ClassDescriptor singleThreadedServlet

bugReporter

private final BugReporter bugReporter

statMap

private final java.util.Map<XField,FindInconsistentSync2.FieldStats> statMap

Constructor Detail

FindInconsistentSync2

public FindInconsistentSync2(BugReporter bugReporter)

Method Detail

isServletField

public static boolean isServletField(XField field)

visitClassContext

public void visitClassContext(ClassContext classContext)

Description copied from interface: Detector

Visit the ClassContext for a class which should be analyzed for instances of bug patterns.

Specified by:

visitClassContext in interface Detector

Parameters:

classContext - the ClassContext

report

public void report()

Description copied from interface: Detector

This method is called after all classes to be visited. It should be used by any detectors which accumulate information over all visited classes to generate results.

Specified by:

report in interface Detector

isConstructor

private static boolean isConstructor(java.lang.String methodName)

analyzeMethod

private void analyzeMethod(ClassContext classContext,
                           org.apache.bcel.classfile.Method method,
                           java.util.Set<org.apache.bcel.classfile.Method> lockedMethodSet)
                    throws CFGBuilderException,
                           DataflowAnalysisException

Throws:

CFGBuilderException

DataflowAnalysisException

isGetterMethod

public static boolean isGetterMethod(ClassContext classContext,
                                     org.apache.bcel.classfile.Method method)

Determine whether or not the given method is a getter method. I.e., if it just returns the value of an instance field.

Parameters:

classContext - the ClassContext for the class containing the method

method - the method

getStats

private FindInconsistentSync2.FieldStats getStats(XField field)

Get the access statistics for given field.

findNotUnlockedMethods

private static java.util.Set<org.apache.bcel.classfile.Method> findNotUnlockedMethods(ClassContext classContext,
                                                                                      SelfCalls selfCalls,
                                                                                      java.util.Set<CallSite> obviouslyLockedSites)

Find methods that appear to never be called from an unlocked context We assume that nonpublic methods will only be called from within the class, which is not really a valid assumption.

findLockedMethods

private static java.util.Set<org.apache.bcel.classfile.Method> findLockedMethods(ClassContext classContext,
                                                                                 SelfCalls selfCalls,
                                                                                 java.util.Set<CallSite> obviouslyLockedSites)

Find methods that appear to always be called from a locked context. We assume that nonpublic methods will only be called from within the class, which is not really a valid assumption.

findObviouslyLockedCallSites

private static java.util.Set<CallSite> findObviouslyLockedCallSites(ClassContext classContext,
                                                                    SelfCalls selfCalls)
                                                             throws CFGBuilderException,
                                                                    DataflowAnalysisException

Find all self-call sites that are obviously locked.

Throws:

CFGBuilderException

DataflowAnalysisException