Package edu.umd.cs.findbugs

Class OpcodeStack

java.lang.Object

edu.umd.cs.findbugs.OpcodeStack

public class OpcodeStack
extends java.lang.Object

tracks the types and numbers of objects that are currently on the operand stack throughout the execution of method. To use, a detector should instantiate one for each method, and call

stack.sawOpcode(this,seen);

at the bottom of their sawOpcode method. at any point you can then inspect the stack and see what the types of objects are on the stack, including constant values if they were pushed. The types described are of course, only the static types. There are some outstanding opcodes that have yet to be implemented, I couldn't find any code that actually generated these, so i didn't put them in because I couldn't test them:

• dup2_x2
• jsr_w
• wide

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	OpcodeStack.CustomUserValue	You can put this annotation on a OpcodeStack detector to indicate that it uses OpcodeStack.Item.userValue, and thus should not reuse generic OpcodeStack information from an iterative evaluation of the opcode stack.
(package private) static class	OpcodeStack.HttpParameterInjection
static class	OpcodeStack.Item
static class	OpcodeStack.JumpInfo
static class	OpcodeStack.JumpInfoFactory

Field Summary

Fields

Modifier and Type	Field	Description
(package private) boolean	backwardsBranch
(package private) static java.util.HashMap<java.lang.String,java.lang.String>	boxedTypes
(package private) int	convertJumpToOneZeroState
(package private) int	convertJumpToZeroOneState
private static boolean	DEBUG
private static boolean	DEBUG2
(package private) boolean	encountedTop
(package private) java.util.BitSet	exceptionHandlers
private java.lang.String	fullyQualifiedMethodName
private static java.util.Map<org.apache.commons.lang3.tuple.Pair<java.lang.String,java.lang.String>,java.lang.String>	IMMUTABLE_RETURNER_MAP
private static java.lang.String	JAVA_UTIL_ARRAYS_ARRAY_LIST
private static java.lang.String	JAVA_UTIL_COLLECTIONS
private java.util.Map<java.lang.Integer,java.util.List<OpcodeStack.Item>>	jumpEntries
private java.util.BitSet	jumpEntryLocations
private boolean	jumpInfoChangedByBackwardsBranch
private boolean	jumpInfoChangedByNewTarget
private java.util.Map<java.lang.Integer,java.util.List<OpcodeStack.Item>>	jumpStackEntries
private java.util.List<java.lang.Integer>	lastUpdate
private java.util.List<OpcodeStack.Item>	lvValues
private java.lang.String	methodName
(package private) boolean	needToMerge
(package private) boolean	oneMeansNull
private boolean	reachOnlyByBranch
(package private) int	registerTestedFoundToBeNonnegative
private boolean	seenTransferOfControl
private java.util.List<OpcodeStack.Item>	stack
private boolean	top
private boolean	useIterativeAnalysis
(package private) DismantleBytecode	v
(package private) int	zeroOneComing

Constructor Summary

Constructors

Constructor	Description
OpcodeStack()

Method Summary

Modifier and Type	Method	Description
private static void	addBoxedType(java.lang.Class<?>... clss)
private void	addJumpValue(int from, int target)
void	clear()
(package private) void	clearJumpInfoChangedByBackwardsBranch()
(package private) void	clearJumpInfoChangedByNewTarget()
private static void	clearRegisterLoad(java.util.List<OpcodeStack.Item> list, int register)
private double	constantToDouble(OpcodeStack.Item it)
private float	constantToFloat(OpcodeStack.Item it)
private int	constantToInt(OpcodeStack.Item it)
private long	constantToLong(OpcodeStack.Item it)
private void	eraseKnowledgeOf(XField fieldOperand)
private org.apache.bcel.classfile.BootstrapMethod	getBootstrapMethod(org.apache.bcel.classfile.Attribute[] attribs, org.apache.bcel.classfile.Constant index)
static java.lang.String	getExceptionSig(DismantleBytecode dbc, org.apache.bcel.classfile.CodeException e)
OpcodeStack.Item	getItemMethodInvokedOn(DismantleBytecode dbc)
private OpcodeStack.JumpInfo	getJumpInfo()
private StackMapAnalyzer.JumpInfoFromStackMap	getJumpInfoFromStackMap()
int	getLastUpdate(int reg)
OpcodeStack.Item	getLVValue(int index)
int	getNumLastUpdates()
int	getNumLocalValues()
int	getStackDepth()
OpcodeStack.Item	getStackItem(int stackOffset)
private java.lang.String	getStringFromIndex(DismantleBytecode dbc, int i)
private void	handleDcmp(int opcode)
private void	handleDup()
private void	handleDup2()
private void	handleDup2X1()
private void	handleDup2X2()
private void	handleDupX1()
private void	handleDupX2()
private void	handleFcmp(int opcode)
private void	handleLcmp()
private void	handleSwap()
boolean	hasIncomingBranches(int pc)
void	initialize()
(package private) boolean	isJumpInfoChangedByBackwardsBranch()
protected boolean	isJumpInfoChangedByNewTarget()
boolean	isJumpTarget(int pc)
private boolean	isMethodThatReturnsGivenReference(java.lang.String clsName, java.lang.String methodName)
(package private) boolean	isReachOnlyByBranch()
boolean	isTop()
void	learnFrom(OpcodeStack.JumpInfo info)
private void	markConstantValueUnknown(OpcodeStack.Item item)
void	mergeJumps(DismantleBytecode dbc)
private boolean	mergeLists(java.util.List<OpcodeStack.Item> mergeInto, java.util.List<OpcodeStack.Item> mergeFrom, boolean errorIfSizesDoNotMatch)
(package private) int	nullSafeSize(java.util.Collection<?> c)
private OpcodeStack.Item	pop()
private void	pop(int count)
void	precomputation(DismantleBytecode dbc)
void	printJumpEntries()
private void	processInvokeDynamic(DismantleBytecode dbc)
private void	processMethodCall(DismantleBytecode dbc, int seen)
private void	push(OpcodeStack.Item i)
private void	pushByConstant(DismantleBytecode dbc, org.apache.bcel.classfile.Constant c)
private void	pushByDoubleMath(int seen, OpcodeStack.Item it, OpcodeStack.Item it2)
private void	pushByFloatMath(int seen, OpcodeStack.Item it, OpcodeStack.Item it2)
private void	pushByIntMath(DismantleBytecode dbc, int seen, OpcodeStack.Item lhs, OpcodeStack.Item rhs)
private void	pushByInvoke(DismantleBytecode dbc, boolean popThis)
private void	pushByLocalLoad(java.lang.String signature, int register)
private void	pushByLocalObjectLoad(DismantleBytecode dbc, int register)
private void	pushByLocalStore(int register)
private void	pushByLongMath(int seen, OpcodeStack.Item lhs, OpcodeStack.Item rhs)
private void	pushBySignature(java.lang.String s, DismantleBytecode dbc)
void	replace(int stackOffset, OpcodeStack.Item value)
void	replaceTop(OpcodeStack.Item newTop)
int	resetForMethodEntry(DismantleBytecode visitor)
private int	resetForMethodEntry0(PreorderVisitor visitor)
(package private) int	resetForMethodEntry0(java.lang.String className, org.apache.bcel.classfile.Method m)
void	sawOpcode(DismantleBytecode dbc, int seen)
void	setJumpInfoChangedByBackwardBranch(java.lang.String kind, int from, int to)
(package private) void	setJumpInfoChangedByBackwardsBranch(int from, int to)
protected void	setJumpInfoChangedByNewTarget()
private void	setLastUpdate(int reg, int pc)
private void	setLVValue(int index, OpcodeStack.Item value)
(package private) void	setReachOnlyByBranch(boolean reachOnlyByBranch)
private void	setTop(boolean top)
private OpcodeStack.Item	top()
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

JAVA_UTIL_ARRAYS_ARRAY_LIST

private static final java.lang.String JAVA_UTIL_ARRAYS_ARRAY_LIST

See Also:

Constant Field Values

JAVA_UTIL_COLLECTIONS

private static final java.lang.String JAVA_UTIL_COLLECTIONS

See Also:

Constant Field Values

DEBUG

private static final boolean DEBUG

DEBUG2

private static final boolean DEBUG2

IMMUTABLE_RETURNER_MAP

private static final java.util.Map<org.apache.commons.lang3.tuple.Pair<java.lang.String,java.lang.String>,java.lang.String> IMMUTABLE_RETURNER_MAP

boxedTypes

@StaticConstant
static final java.util.HashMap<java.lang.String,java.lang.String> boxedTypes

stack

private java.util.List<OpcodeStack.Item> stack

lvValues

private java.util.List<OpcodeStack.Item> lvValues

lastUpdate

private final java.util.List<java.lang.Integer> lastUpdate

top

private boolean top

seenTransferOfControl

private boolean seenTransferOfControl

useIterativeAnalysis

private final boolean useIterativeAnalysis

encountedTop

boolean encountedTop

backwardsBranch

boolean backwardsBranch

exceptionHandlers

java.util.BitSet exceptionHandlers

jumpInfoChangedByBackwardsBranch

private boolean jumpInfoChangedByBackwardsBranch

jumpInfoChangedByNewTarget

private boolean jumpInfoChangedByNewTarget

jumpEntries

private java.util.Map<java.lang.Integer,java.util.List<OpcodeStack.Item>> jumpEntries

jumpStackEntries

private java.util.Map<java.lang.Integer,java.util.List<OpcodeStack.Item>> jumpStackEntries

jumpEntryLocations

private java.util.BitSet jumpEntryLocations

convertJumpToOneZeroState

int convertJumpToOneZeroState

convertJumpToZeroOneState

int convertJumpToZeroOneState

registerTestedFoundToBeNonnegative

int registerTestedFoundToBeNonnegative

zeroOneComing

int zeroOneComing

oneMeansNull

boolean oneMeansNull

needToMerge

boolean needToMerge

reachOnlyByBranch

private boolean reachOnlyByBranch

methodName

private java.lang.String methodName

fullyQualifiedMethodName

private java.lang.String fullyQualifiedMethodName

v

DismantleBytecode v

Constructor Detail

OpcodeStack

public OpcodeStack()

Method Detail

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

hasIncomingBranches

public boolean hasIncomingBranches(int pc)

getExceptionSig

public static java.lang.String getExceptionSig(DismantleBytecode dbc,
                                               org.apache.bcel.classfile.CodeException e)

mergeJumps

public void mergeJumps(DismantleBytecode dbc)

setLastUpdate

private void setLastUpdate(int reg,
                           int pc)

getLastUpdate

public int getLastUpdate(int reg)

getNumLastUpdates

public int getNumLastUpdates()

sawOpcode

public void sawOpcode(DismantleBytecode dbc,
                      int seen)

eraseKnowledgeOf

private void eraseKnowledgeOf(XField fieldOperand)

precomputation

public void precomputation(DismantleBytecode dbc)

constantToInt

private int constantToInt(OpcodeStack.Item it)

constantToFloat

private float constantToFloat(OpcodeStack.Item it)

constantToDouble

private double constantToDouble(OpcodeStack.Item it)

constantToLong

private long constantToLong(OpcodeStack.Item it)

handleDcmp

private void handleDcmp(int opcode)

handleFcmp

private void handleFcmp(int opcode)

handleLcmp

private void handleLcmp()

handleSwap

private void handleSwap()

handleDup

private void handleDup()

handleDupX1

private void handleDupX1()

handleDup2

private void handleDup2()

handleDup2X1

private void handleDup2X1()

handleDup2X2

private void handleDup2X2()

handleDupX2

private void handleDupX2()

addBoxedType

private static void addBoxedType(java.lang.Class<?>... clss)

markConstantValueUnknown

private void markConstantValueUnknown(OpcodeStack.Item item)

processMethodCall

private void processMethodCall(DismantleBytecode dbc,
                               int seen)

isMethodThatReturnsGivenReference

private boolean isMethodThatReturnsGivenReference(java.lang.String clsName,
                                                  java.lang.String methodName)

processInvokeDynamic

private void processInvokeDynamic(DismantleBytecode dbc)

getBootstrapMethod

private org.apache.bcel.classfile.BootstrapMethod getBootstrapMethod(org.apache.bcel.classfile.Attribute[] attribs,
                                                                     org.apache.bcel.classfile.Constant index)

mergeLists

private boolean mergeLists(java.util.List<OpcodeStack.Item> mergeInto,
                           java.util.List<OpcodeStack.Item> mergeFrom,
                           boolean errorIfSizesDoNotMatch)

clear

public void clear()

printJumpEntries

public void printJumpEntries()

isJumpTarget

public boolean isJumpTarget(int pc)

addJumpValue

private void addJumpValue(int from,
                          int target)

learnFrom

public void learnFrom(OpcodeStack.JumpInfo info)

initialize

public void initialize()

resetForMethodEntry

public int resetForMethodEntry(DismantleBytecode visitor)

nullSafeSize

int nullSafeSize(@CheckForNull
                 java.util.Collection<?> c)

getJumpInfo

private OpcodeStack.JumpInfo getJumpInfo()

getJumpInfoFromStackMap

private StackMapAnalyzer.JumpInfoFromStackMap getJumpInfoFromStackMap()

setJumpInfoChangedByBackwardBranch

public void setJumpInfoChangedByBackwardBranch(java.lang.String kind,
                                               int from,
                                               int to)

resetForMethodEntry0

private int resetForMethodEntry0(PreorderVisitor visitor)

resetForMethodEntry0

int resetForMethodEntry0(@SlashedClassName
                         java.lang.String className,
                         org.apache.bcel.classfile.Method m)

getStackDepth

public int getStackDepth()

getStackItem

public OpcodeStack.Item getStackItem(int stackOffset)

pop

private OpcodeStack.Item pop()

top

private OpcodeStack.Item top()

replace

public void replace(int stackOffset,
                    OpcodeStack.Item value)

replaceTop

public void replaceTop(OpcodeStack.Item newTop)

pop

private void pop(int count)

push

private void push(OpcodeStack.Item i)

pushByConstant

private void pushByConstant(DismantleBytecode dbc,
                            org.apache.bcel.classfile.Constant c)

pushByLocalObjectLoad

private void pushByLocalObjectLoad(DismantleBytecode dbc,
                                   int register)

pushByIntMath

private void pushByIntMath(DismantleBytecode dbc,
                           int seen,
                           OpcodeStack.Item lhs,
                           OpcodeStack.Item rhs)

pushByLongMath

private void pushByLongMath(int seen,
                            OpcodeStack.Item lhs,
                            OpcodeStack.Item rhs)

pushByFloatMath

private void pushByFloatMath(int seen,
                             OpcodeStack.Item it,
                             OpcodeStack.Item it2)

pushByDoubleMath

private void pushByDoubleMath(int seen,
                              OpcodeStack.Item it,
                              OpcodeStack.Item it2)

pushByInvoke

private void pushByInvoke(DismantleBytecode dbc,
                          boolean popThis)

getItemMethodInvokedOn

public OpcodeStack.Item getItemMethodInvokedOn(DismantleBytecode dbc)

getStringFromIndex

private java.lang.String getStringFromIndex(DismantleBytecode dbc,
                                            int i)

pushBySignature

private void pushBySignature(java.lang.String s,
                             DismantleBytecode dbc)

pushByLocalStore

private void pushByLocalStore(int register)

clearRegisterLoad

private static void clearRegisterLoad(java.util.List<OpcodeStack.Item> list,
                                      int register)

pushByLocalLoad

private void pushByLocalLoad(java.lang.String signature,
                             int register)

setLVValue

private void setLVValue(int index,
                        OpcodeStack.Item value)

getLVValue

@Nonnull
public OpcodeStack.Item getLVValue(int index)

getNumLocalValues

public int getNumLocalValues()

setTop

private void setTop(boolean top)

isTop

public boolean isTop()

setReachOnlyByBranch

void setReachOnlyByBranch(boolean reachOnlyByBranch)

isReachOnlyByBranch

boolean isReachOnlyByBranch()

isJumpInfoChangedByBackwardsBranch

boolean isJumpInfoChangedByBackwardsBranch()

clearJumpInfoChangedByBackwardsBranch

void clearJumpInfoChangedByBackwardsBranch()

setJumpInfoChangedByBackwardsBranch

void setJumpInfoChangedByBackwardsBranch(int from,
                                         int to)

isJumpInfoChangedByNewTarget

protected boolean isJumpInfoChangedByNewTarget()

Returns:

Returns the jumpInfoChangedByNewTarget.

clearJumpInfoChangedByNewTarget

void clearJumpInfoChangedByNewTarget()

setJumpInfoChangedByNewTarget

protected void setJumpInfoChangedByNewTarget()