Packages

  • package root
    Definition Classes
    root
  • package org
    Definition Classes
    root
  • package opalj

    OPAL is a Scala-based framework for the static analysis, manipulation and creation of Java bytecode.

    OPAL is a Scala-based framework for the static analysis, manipulation and creation of Java bytecode. OPAL is designed with performance, scalability and adaptability in mind.

    Its main components are:

    • a library (Common) which provides generally useful data-structures and algorithms for static analyses.
    • a framework for parsing Java bytecode (Bytecode Infrastructure) that can be used to create arbitrary representations.
    • a library to create a one-to-one in-memory representation of Java bytecode (Bytecode Disassembler).
    • a library to create a representation of Java bytecode that facilitates writing simple static analyses (Bytecode Representation - org.opalj.br).
    • a scalable, easily customizable framework for the abstract interpretation of Java bytecode (Abstract Interpretation Framework - org.opalj.ai).
    • a library to extract dependencies between code elements and to facilitate checking architecture definitions.
    • a library for the lightweight manipulation and creation of Java bytecode.

    General Design Decisions

    Thread Safety

    Unless explicitly noted, OPAL is thread safe. I.e., the classes defined by OPAL can be considered to be thread safe unless otherwise stated. (For example, it is possible to read and process class files concurrently without explicit synchronization on the client side.)

    No null Values

    Unless explicitly noted, OPAL does not null values I.e., fields that are accessible will never contain null values and methods will never return null. If a method accepts null as a value for a parameter or returns a null value it is always explicitly documented. In general, the behavior of methods that are passed null values is undefined unless explicitly documented.

    No Typecasts for Collections

    For efficiency reasons, OPAL sometimes uses mutable data-structures internally. After construction time, these data-structures are generally represented using their generic interfaces (e.g., scala.collection.{Set,Map}). However, a downcast (e.g., to add/remove elements) is always forbidden as it would effectively prevent thread-safety. Furthermore, the concrete data-structure is always considered an implementation detail and may change at any time.

    Assertions

    OPAL makes heavy use of Scala's Assertion Facility to facilitate writing correct code. Hence, for production builds (after thorough testing(!)) it is highly recommend to build OPAL again using -Xdisable-assertions.

    Definition Classes
    org
  • package ai

    Implementation of an abstract interpretation (ai) framework – also referred to as OPAL.

    Implementation of an abstract interpretation (ai) framework – also referred to as OPAL.

    Please note, that OPAL/the abstract interpreter just refers to the classes and traits defined in this package (ai). The classes and traits defined in the sub-packages (in particular in domain) are not considered to be part of the core of OPAL/the abstract interpreter.

    Definition Classes
    opalj
    Note

    This framework assumes that the analyzed bytecode is valid; i.e., the JVM's bytecode verifier would be able to verify the code. Furthermore, load-time errors (e.g., LinkageErrors) are – by default – completely ignored to facilitate the analysis of parts of a project. In general, if the presented bytecode is not valid, the result is undefined (i.e., OPAL may report meaningless results, crash or run indefinitely).

    See also

    org.opalj.ai.Domain - The core interface between the abstract interpretation framework and the abstract domain that is responsible for performing the abstract computations.

    org.opalj.ai.AI - Implements the abstract interpreter that processes a methods code and uses an analysis-specific domain to perform the abstract computations.

  • package domain

    This package contains definitions of common domains that can be used for the implementation of analyses.

    This package contains definitions of common domains that can be used for the implementation of analyses.

    Types of Domains

    In general, we distinguish two types of domains. First, domains that define a general interface (on top of the one defined by Domain), but do not directly provide an implementation. Hence, whenever you develop a new Domain you should consider implementing/using these domains to maximize reusability. Second, Domains that implement a specific interface (trait). In this case, we further distinguish between domains that provide a default implementation (per interface only one of these Domains can be used to create a final Domain) and those that can be stacked and basically refine the overall functionality.

    Examples

    • Domains That Define a General Interface
      • Origin defines two types which domains that provide information abou the origin of a value should consider to implement.
      • TheProject defines a standard mechanism how a domain can access the current project.
      • TheClassHierarchy defines a standard mechanism how to get the project's class hierarchy.
      • ...
    • Domains That Provide a Default Implementation
      • Origin defines the functionality to return a value's origin if the value supports that.
      • TheProject default implementation of the TheClassHierarchy trait that uses the project's class hierarchy.
      • DefaultHandlingOfMethodResults basically implements a Domain's methods related to return instructions an uncaught exceptions.
      • ...
    • Domains That Implement Stackable Functionality
      • RecordThrownExceptions records information about all uncaught exceptions by intercepting a Domain's respective methods. However, it does provide a default implementation. Hence, a typical pattern is:
    class MyDomain extends Domain with ...
        with DefaultHandlingOfMethodResults with RecordThrownExceptions

    Thread Safety

    Unless explicitly documented, a domain is never thread-safe. The general programming model is to use one Domain object per code block/method and therefore, thread-safety is not required for Domains that are used for the evaluation of methods. However domains that are used to adapt/transfer values should be thread safe (see ValuesCoordinatingDomain for further details).

    Definition Classes
    ai
  • package l0
    Definition Classes
    domain
  • package l1

    Commonly useful methods.

    Commonly useful methods.

    Definition Classes
    domain
  • package l2
    Definition Classes
    domain
  • package la
    Definition Classes
    domain
  • package li
    Definition Classes
    domain
  • package tracing
    Definition Classes
    domain
  • AsDomainValue
  • AsJavaObject
  • ConcreteIntegerValues
  • ConcreteLongValues
  • ConstantFieldValuesResolution
  • CurrentCode
  • DefaultDomainValueBinding
  • DefaultExceptionsFactory
  • DefaultHandlingForReturnInstructions
  • DefaultHandlingForThrownExceptions
  • DefaultHandlingOfMethodResults
  • DefaultHandlingOfVoidReturns
  • DefaultRecordMethodCallResults
  • DomainId
  • DomainValues
  • GeneralizedArrayHandling
  • IgnoreSynchronization
  • ImpossibleRefinement
  • MethodCallResults
  • MethodCallsHandling
  • MonitorInstructionsTracker
  • Origin
  • Origins
  • PerInstructionPostProcessing
  • PerformAI
  • PostEvaluationMemoryManagement
  • PredefinedClassHierarchy
  • RecordAllThrownExceptions
  • RecordCFG
  • RecordConstraints
  • RecordDefUse
  • RecordJoinedThrownExceptions
  • RecordLastReturnedValues
  • RecordMethodCallResults
  • RecordReturnFromMethodInstructions
  • RecordReturnedValue
  • RecordReturnedValueInfrastructure
  • RecordReturnedValues
  • RecordReturnedValuesInfrastructure
  • RecordThrownExceptions
  • RecordVoidReturns
  • RefineDefUseUsingOrigins
  • ReifiedConstraints
  • ReturnInstructionsDomain
  • SpecialMethodsHandling
  • TheCode
  • TheMethod
  • TheProject
  • ThePropertyStore
  • ThrowAllPotentialExceptionsConfiguration
  • ThrowNoPotentialExceptionsConfiguration
  • ValuesCoordinatingDomain
t

org.opalj.ai.domain

PerInstructionPostProcessing

trait PerInstructionPostProcessing extends CoreDomainFunctionality

Provides the generic infrastructure to register a function that updates the operands and locals associated with an instruction that will be evaluated "next". For example, let's assume that we are currently processing instruction X and that instruction Y is the successor instruction. In this case, the framework will first determine the effect of function X on the stack/locals. After that, all registered updaters will be called. All registered updaters will be discarded as soon the evaluation of instruction X has completed.

Source
PerInstructionPostProcessing.scala
Linear Supertypes
Ordering
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  2. By Inheritance
Inherited
  1. PerInstructionPostProcessing
  2. CoreDomainFunctionality
  3. SubroutinesDomain
  4. ValuesDomain
  5. AnyRef
  6. Any
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Visibility
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Type Members

  1. class IllegalValue extends Value

    Represents a value that has no well defined state/type.

    Represents a value that has no well defined state/type. Such values are the result of a join of two incompatible values and are generally only found in registers (in the locals) and then identify a value that is dead.

    Attributes
    protected
    Definition Classes
    ValuesDomain
    See also

    org.opalj.ai.Domain.Value for further details.

  2. trait RETValue extends Value
    Definition Classes
    ValuesDomain
  3. trait ReferenceValue extends TypedValue[ReferenceType] with IsReferenceValue[DomainReferenceValue]
    Definition Classes
    ValuesDomain
  4. class ReturnAddressValue extends RETValue

    Stores a single return address (i.e., a program counter/index into the code array).

    Stores a single return address (i.e., a program counter/index into the code array).

    Definition Classes
    ValuesDomain
    Note

    Though the framework completely handles all aspects related to return address values, it is nevertheless necessary that this class inherits from Value as return addresses are stored on the stack/in the registers. However, if the Value trait should be refined, all additional methods may – from the point-of-view of OPAL-AI - just throw an OperationNotSupportedException as these additional methods will never be called by OPAL-AI.

  5. class ReturnAddressValues extends RETValue

    A collection of (not furhter stored) return address values.

    A collection of (not furhter stored) return address values. Primarily used when we join the executions of subroutines.

    Definition Classes
    ValuesDomain
  6. trait TypedValue[+T <: Type] extends Value with KnownType
    Definition Classes
    ValuesDomain
  7. trait Value extends AnyRef

    Abstracts over a concrete operand stack value or a value stored in one of the local variables/registers.

    Abstracts over a concrete operand stack value or a value stored in one of the local variables/registers.

    Use Of Value/Dependencies On Value

    In general, subclasses and users of a Domain should not have/declare a direct dependency on Value. Instead they should use DomainValue as otherwise extensibility of a Domain may be hampered or even be impossible. The only exceptions are, of course, classes that directly inherit from this class.

    Refining Value

    If you directly extend/refine this trait (i.e., in a subclass of the Domain trait you write something like trait Value extends super.Value), make sure that you also extend all classes/traits that inherit from this type (this may require a deep mixin composition and that you refine the type DomainType accordingly). However, OPAL was designed such that extending this class should – in general – not be necessary. It may also be easier to encode the desired semantics – as far as possible – as part of the domain.

    Implementing Value

    Standard inheritance from this trait is always supported and is the primary mechanism to model an abstract domain's lattice w.r.t. some special type of value. In general, the implementation should try to avoid creating new instances of values unless strictly required to model the domain's semantics. This will greatly improve the overall performance as this framework heavily uses reference-based equality checks to speed up the evaluation.

    Definition Classes
    ValuesDomain
    Note

    OPAL does not rely on any special equality semantics w.r.t. values and never directly or indirectly calls a Value's equals or eq method. Hence, a domain can encode equality such that it best fits its need. However, some of the provided domains rely on the following semantics for equals: Two domain values have to be equal (==) iff they represent the same information. This includes additional information, such as, the value of the origin. E.g., a value (AnIntegerValue) that represents an arbitrary Integer value has to return true if the domain value with which it is compared also represents an arbitrary Integer value (AnIntegerValue). However, it may still be necessary to use multiple objects to represent an arbitrary integer value if, e.g., constraints should be attached to specific values. For example, after a comparison of an integer value with a predefined value (e.g., AnIntegerValue < 4) it is possible to constrain the respective value on the subsequent paths (< 4 on one path and >= 4 on the other path). To make that possible, it is however necessary to distinguish the AnIntegervalue from some other AnIntegerValue to avoid constraining unrelated values.

    public void foo(int a,int b) {
        if(a < 4) {
            z = a - 2 // here a is constrained (< 4), b and z are unconstrained
        }
        else {
            z = a + 2 // here a is constrained (>= 4), b and z are unconstrained
        }
    }

    In general, equals is only defined for values belonging to the same domain. If values need to be compared across domains, they need to be adapted to a target domain first.

  8. abstract type DomainIllegalValue <: IllegalValue with DomainValue

    Abstracts over the concrete type of IllegalValue.

    Abstracts over the concrete type of IllegalValue.

    This type needs to be refined whenever the class IllegalValue is refined or the type DomainValue is refined.

    Definition Classes
    ValuesDomain
  9. abstract type DomainReferenceValue >: Null <: ReferenceValue with DomainTypedValue[ReferenceType]
    Definition Classes
    ValuesDomain
  10. abstract type DomainReturnAddressValue <: ReturnAddressValue with DomainValue

    Abstracts over the concrete type of ReturnAddressValue.

    Abstracts over the concrete type of ReturnAddressValue. Needs to be fixed by some sub-trait/sub-class. In the simplest case (i.e., when neither the Value trait nor the ReturnAddressValue trait was refined) it is sufficient to write:

    type DomainReturnAddressValue = ReturnAddressValue
    Definition Classes
    ValuesDomain
  11. abstract type DomainReturnAddressValues <: ReturnAddressValues with DomainValue
    Definition Classes
    ValuesDomain
  12. abstract type DomainTypedValue[+T <: Type] >: Null <: DomainValue
    Definition Classes
    ValuesDomain
  13. abstract type DomainValue >: Null <: Value

    Abstracts over the concrete type of Value.

    Abstracts over the concrete type of Value. Needs to be refined by traits that inherit from Domain and which extend Domain's Value trait.

    Definition Classes
    ValuesDomain
  14. type DomainValueUpdater = (DomainValue) ⇒ DomainValue
  15. type ExceptionValue = DomainReferenceValue

    A simple type alias of the type DomainValue; used to facilitate comprehension.

    A simple type alias of the type DomainValue; used to facilitate comprehension.

    Definition Classes
    ValuesDomain
  16. type ExceptionValues = Iterable[ExceptionValue]

    A type alias for Iterables of ExceptionValues; used to facilitate comprehension.

    A type alias for Iterables of ExceptionValues; used to facilitate comprehension.

    Definition Classes
    ValuesDomain
  17. type Locals = collection.mutable.Locals[DomainValue]

    An instruction's current register values/locals are represented using an array.

    An instruction's current register values/locals are represented using an array.

    Definition Classes
    ValuesDomain
  18. type LocalsArray = Array[Locals]
    Definition Classes
    ValuesDomain
  19. type Operands = Chain[DomainValue]

    An instruction's operands are represented using a list where the first element of the list represents the top level operand stack value.

    An instruction's operands are represented using a list where the first element of the list represents the top level operand stack value.

    Definition Classes
    ValuesDomain
  20. type OperandsArray = Array[Operands]
    Definition Classes
    ValuesDomain

Abstract Value Members

  1. abstract val DomainReferenceValue: ClassTag[DomainReferenceValue]

    The class tag can be used to create type safe arrays or to extract the concrete type of the domain value.

    The class tag can be used to create type safe arrays or to extract the concrete type of the domain value.

    val DomainReferenceValue(v) = value // of type "DomainValue"
    // v is now of the type DomainReferenceValue
    Definition Classes
    ValuesDomain
  2. implicit abstract val DomainValue: ClassTag[DomainValue]

    The class tag for the type DomainValue.

    The class tag for the type DomainValue.

    Required to generate instances of arrays in which values of type DomainValue can be stored in a type-safe manner.

    Initialization

    In the sub-trait or class that fixes the type of DomainValue it is necessary to implement this abstract val using:

    val DomainValueTag : ClassTag[DomainValue] = implicitly

    (As of Scala 2.10 it is necessary that you do not use implicit in the subclass - it will compile, but fail at runtime.)

    Definition Classes
    ValuesDomain
  3. abstract def MetaInformationUpdateIllegalValue: MetaInformationUpdate[DomainIllegalValue]

    The result of the merge of two incompatible values has to be reported as a MetaInformationUpdate[DomainIllegalValue].

    The result of the merge of two incompatible values has to be reported as a MetaInformationUpdate[DomainIllegalValue].

    Definition Classes
    ValuesDomain
  4. abstract def ReturnAddressValue(address: PC): DomainReturnAddressValue

    Factory method to create an instance of a ReturnAddressValue.

    Factory method to create an instance of a ReturnAddressValue.

    Definition Classes
    ValuesDomain
  5. abstract val TheIllegalValue: DomainIllegalValue

    The singleton instance of the IllegalValue.

    The singleton instance of the IllegalValue.

    Definition Classes
    ValuesDomain
  6. abstract val TheReturnAddressValues: DomainReturnAddressValues

    The singleton instance of ReturnAddressValues

    The singleton instance of ReturnAddressValues

    Definition Classes
    ValuesDomain

Concrete Value Members

  1. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  2. final def ##(): Int
    Definition Classes
    AnyRef → Any
  3. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  4. final def StructuralUpdateIllegalValue: StructuralUpdate[Nothing]

    The result of merging two values should never be reported as a StructuralUpdate if the computed value is an IllegalValue.

    The result of merging two values should never be reported as a StructuralUpdate if the computed value is an IllegalValue. The JVM semantics guarantee that the value will not be used and, hence, continuing the interpretation is meaningless.

    Definition Classes
    ValuesDomain
    Note

    This method is solely defined for documentation purposes and to catch implementation errors early on.

  5. def abstractInterpretationEnded(aiResult: AIResult { val domain: PerInstructionPostProcessing.this.type }): Unit

    Called by the abstract interpreter when the abstract interpretation of a method has ended.

    Called by the abstract interpreter when the abstract interpretation of a method has ended. The abstract interpretation of a method ends if either the fixpoint is reached or the interpretation was aborted.

    By default this method does nothing.

    Domains that override this method are expected to also call super.abstractInterpretationEnded(aiResult).

    Definition Classes
    CoreDomainFunctionality
  6. def afterBaseJoin(pc: PC): Unit

    This method is called after all values which differ have been joined, but before joinPostProcessing will be called.

    This method is called after all values which differ have been joined, but before joinPostProcessing will be called.

    Attributes
    protected[this]
    Definition Classes
    CoreDomainFunctionality
  7. def afterEvaluation(pc: PC, instruction: Instruction, oldOperands: Operands, oldLocals: Locals, targetPC: PC, isExceptionalControlFlow: Boolean, newOperands: Operands, newLocals: Locals): (Operands, Locals)

    This methods is called after the evaluation of the instruction with the given pc with respect to targetPC, but before the values are propagated (joined) and before it is checked whether the interpretation needs to be continued.

    This methods is called after the evaluation of the instruction with the given pc with respect to targetPC, but before the values are propagated (joined) and before it is checked whether the interpretation needs to be continued. I.e., if the operands (newOperands) or locals (newLocals) are further refined then the refined operands and locals are joined (if necessary).

    Definition Classes
    CoreDomainFunctionality
    Note

    During the evaluation of the instruction it is possible that this method is called multiple times with different targetPCs. The latter is not only true for control flow instructions, but also for those instructions that may raise an exception. This method can and is intended to be overridden to further refine the operand stack/the locals. However, the overriding method should always forward the (possibly refined) operands and locals to the super method (stackable traits).

  8. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  9. def beforeBaseJoin(pc: PC): Unit

    This method is called immediately before a join operation with regard to the specified pc is performed.

    This method is called immediately before a join operation with regard to the specified pc is performed.

    Attributes
    protected[this]
    Definition Classes
    CoreDomainFunctionality
    Note

    This method is intended to be overwritten by clients to perform custom operations.

  10. def clone(): AnyRef
    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @native() @throws( ... )
  11. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  12. def equals(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  13. def evaluationCompleted(pc: PC, worklist: Chain[PC], evaluated: Chain[PC], operandsArray: OperandsArray, localsArray: LocalsArray, tracer: Option[AITracer]): Unit

    Called by the framework after evaluating the instruction with the given pc.

    Called by the framework after evaluating the instruction with the given pc. I.e., the state of all potential successor instructions was updated and the flow method was called – potentially multiple times – accordingly.

    By default this method does nothing.

    Definition Classes
    PerInstructionPostProcessingCoreDomainFunctionality
  14. def finalize(): Unit
    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( classOf[java.lang.Throwable] )
  15. def flow(currentPC: PC, currentOperands: Operands, currentLocals: Locals, successorPC: PC, isSuccessorScheduled: Answer, isExceptionalControlFlow: Boolean, abruptSubroutineTerminationCount: Int, wasJoinPerformed: Boolean, worklist: Chain[PC], operandsArray: OperandsArray, localsArray: LocalsArray, tracer: Option[AITracer]): Chain[PC]

    Called by the framework after performing a computation to inform the domain about the result.

    Called by the framework after performing a computation to inform the domain about the result. That is, after evaluating the effect of the instruction with currentPC on the current stack and register and (if necessary) joining the updated stack and registers with the stack and registers associated with the instruction successorPC. (Hence, this method is ONLY called for return instructions if the return instruction throws an IllegalMonitorStateException.) This function basically informs the domain about the instruction that may be evaluated next. The flow function is called for every possible successor of the instruction with currentPC. This includes all branch targets as well as those instructions that handle exceptions.

    In some cases it will even be the case that flow is called multiple times with the same pair of program counters: (currentPC, successorPC). This may happen, e.g., in case of a switch instruction where multiple values have the same body/target instruction and we do not have precise information about the switch value. E.g., as in the following snippet:

    switch (i) {  // pc: X => Y (for "1"), Y (for "2"), Y (for "3")
    case 1:
    case 2:
    case 3: System.out.println("Great.");            // pc: Y
    default: System.out.println("Not So Great.");    // pc: Z
    }

    The flow function is also called after instructions that are domain independent such as dup and load instructions which just manipulate the registers and stack in a generic way. This enables the domain to precisely follow the evaluation progress and in particular to perform control-flow dependent analyses.

    currentPC

    The program counter of the instruction that is currently evaluated by the abstract interpreter.

    currentOperands

    The current operands. I.e., the operand stack before the instruction is evaluated.

    currentLocals

    The current locals. I.e., the locals before the instruction is evaluated.

    successorPC

    The program counter of an instruction that is a potential successor of the instruction with currentPC. In general the AI framework adds the pc of the successor instruction to the beginning of the worklist unless it is a join instruction. In this case the pc is added to the end – in the context of the current (sub)routine. Hence, the AI framework first evaluates all paths leading to a join instruction before the join instruction will be evaluated.

    isSuccessorScheduled

    Yes if the successor instruction is or was scheduled. I.e., Yes is returned if the worklist contains successorPC, No if the worklist does not contain successorPC. Unknown is returned if the AI framework did not process the worklist and doesn't know anything about the scheduled successors. Note that this value is independent of the subroutine in which the value may be scheduled. If an implementation schedules successorPC the the super call has to set isSuccessorScheduled to Yes.

    isExceptionalControlFlow

    true if and only if the evaluation of the instruction with the program counter currentPC threw an exception; false otherwise. Hence, if this parameter is true the instruction with successorPC is the first instruction of the handler.

    abruptSubroutineTerminationCount

    > 0 if and only if we have an exceptional control flow that terminates one or more subroutines. In this case the successor instruction is scheduled (if at all) after all subroutines that will be terminated by the exception.

    wasJoinPerformed

    true if a join was performed. I.e., the successor instruction is an instruction (Code.cfJoins) that was already previously evaluated and where multiple paths potentially join.

    worklist

    The current list of instructions that will be evaluated next.

    If subroutines are not used (i.e., Java >= 5)

    If you want to force the evaluation of the instruction with the program counter successorPC it is sufficient to test whether the list already contains successorPC and – if not – to prepend it. If the worklist already contains successorPC then the domain is allowed to move the PC to the beginning of the worklist.

    If the code contains subroutines (JSR/RET)

    If the PC does not belong to the same (current) (sub)routine, it is not allowed to be moved to the beginning of the worklist. (Subroutines can only be found in code generated by old Java compilers; before Java 6. Subroutines are identified by jsr/ret instructions. A subroutine can be identified by going back in the worklist and by looking for specific "program counters" (e.g., SUBROUTINE_START, SUBROUTINE_END). These program counters mark the beginning of a subroutine. In other words, an instruction can be freely moved around unless a special program counter value is found. All special program counters use negative values. Additionally, neither the negative values nor the positive values between two negative values should be changed. Furthermore, no value (PC) should be put between negative values that capture subroutine information. If the domain updates the worklist, it is the responsibility of the domain to call the tracer and to inform it about the changes. Note that the worklist is not allowed to contain duplicates related to the evaluation of the current (sub-)routine.

    operandsArray

    The array that associates every instruction with its operand stack that is in effect. Note, that only those elements of the array contain values that are related to instructions that were evaluated in the past; the other elements are null. Furthermore, it identifies the operandsArray of the subroutine that will execute the instruction with successorPC. The operandsArray may be null for the current instruction (not the successor instruction) if the execution of the current instruction leads to the termination of the current subroutine. In this case the information about the operands and locals associated with all instructions belonging to the subroutine is reset.

    localsArray

    The array that associates every instruction with its current register values. Note, that only those elements of the array contain values that are related to instructions that were evaluated in the past. The other elements are null. Furthermore, it identifies the localsArray of the subroutine that will execute the instruction with successorPC. The localsArray may be null for the current instruction (not the successor instruction) if the execution of the current instruction leads to the termination of the current subroutine. In this case the information about the operands and locals associated with all instructions belonging to the subroutine is reset.

    returns

    The updated worklist. In most cases this is simply the given worklist. The default case is also to return the given worklist.

    Definition Classes
    PerInstructionPostProcessingCoreDomainFunctionality
    Note

    A method that overrides this method must always call the super method to ensure that every domain that uses this hook gets informed about a flow.

    ,

    The domain is allowed to modify the worklist, operandsArray and localsArray. However, the AI will not perform any checks. In case of updates of the operandsArray or localsArray it is necessary to first create a shallow copy before updating it. If this is not done, it may happen that the locals associated with other instructions are also updated.

  16. final def getClass(): Class[_]
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  17. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  18. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  19. def join(pc: PC, thisOperands: Operands, thisLocals: Locals, otherOperands: Operands, otherLocals: Locals): Update[(Operands, Locals)]

    Joins the given operand stacks and local variables.

    Joins the given operand stacks and local variables.

    In general there should be no need to refine this method. Overriding this method should only be done for analysis purposes.

    Performance

    This method heavily relies on reference comparisons to speed up the overall process of performing an abstract interpretation of a method. Hence, a computation should – whenever possible – return (one of) the original object(s) if that value has the same abstract state as the result. Furthermore, if all original values capture the same abstract state as the result of the computation, the "left" value/the value that was already used in the past should be returned.

    returns

    The joined operand stack and registers. Returns NoUpdate if this memory layout already subsumes the other memory layout.

    Definition Classes
    CoreDomainFunctionality
    Note

    The operand stacks are guaranteed to contain compatible values w.r.t. the computational type (unless the bytecode is not valid or OPAL contains an error). I.e., if the result of joining two operand stack values is an IllegalValue we assume that the domain implementation is incorrect. However, the joining of two register values can result in an illegal value - which identifies the value as being dead.

    ,

    The size of the operands stacks that are to be joined and the number of registers/locals that are to be joined can be expected to be identical under the assumption that the bytecode is valid and the framework contains no bugs.

  20. def joinPostProcessing(updateType: UpdateType, pc: PC, oldOperands: Operands, oldLocals: Locals, newOperands: Operands, newLocals: Locals): Update[(Operands, Locals)]

    Enables the customization of the behavior of the base join method.

    Enables the customization of the behavior of the base join method.

    This method in particular enables, in case of a MetaInformationUpdate, to raise the update type to force the continuation of the abstract interpretation process.

    Methods should always override this method and should call the super method.

    updateType

    The current update type. The level can be raised. It is an error to lower the update level.

    oldOperands

    The old operands, before the join. Should not be changed.

    oldLocals

    The old locals, before the join. Should not be changed.

    newOperands

    The new operands; may be updated.

    newLocals

    The new locals; may be updated.

    Attributes
    protected[this]
    Definition Classes
    CoreDomainFunctionality
  21. def joinValues(pc: PC, left: DomainValue, right: DomainValue): Update[DomainValue]
    Attributes
    protected[this]
    Definition Classes
    CoreDomainFunctionality
  22. def jumpToSubroutine(pc: PC, branchTarget: PC, returnTarget: PC): Unit

    pc

    The pc of the jsr(w) instruction.

    Definition Classes
    SubroutinesDomain
  23. def mergeDomainValues(pc: PC, v1: DomainValue, v2: DomainValue): DomainValue

    Merges the given domain value v1 with the domain value v2 and returns the merged value which is v1 if v1 is an abstraction of v2, v2 if v2 is an abstraction of v1 or some other value if a new value is computed that abstracts over both values.

    Merges the given domain value v1 with the domain value v2 and returns the merged value which is v1 if v1 is an abstraction of v2, v2 if v2 is an abstraction of v1 or some other value if a new value is computed that abstracts over both values.

    This operation is commutative.

    Definition Classes
    ValuesDomain
  24. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  25. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  26. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  27. def properties(pc: PC, propertyToString: (AnyRef) ⇒ String = (v) ⇒ v.toString): Option[String]

    Returns a string representation of the properties associated with the instruction with the respective program counter.

    Returns a string representation of the properties associated with the instruction with the respective program counter.

    Associating properties with an instruction and maintaining those properties is, however, at the sole responsibility of the Domain.

    This method is predefined to facilitate the development of support tools and is not used by the abstract interpretation framework.

    Domains that define (additional) properties should (abstract) override this method and should return a textual representation of the property.

    Definition Classes
    ValuesDomain
  28. def registerOnControlFlowUpdater(f: (DomainValue) ⇒ DomainValue): Unit

  29. def registerOnExceptionalControlFlowUpdater(f: (DomainValue) ⇒ DomainValue): Unit
  30. def registerOnRegularControlFlowUpdater(f: (DomainValue) ⇒ DomainValue): Unit
  31. def returnFromSubroutine(pc: PC, lvIndex: Int): Unit

    pc

    The pc of the ret instruction.

    Definition Classes
    SubroutinesDomain
  32. def schedule(successorPC: PC, abruptSubroutineTerminationCount: Int, worklist: Chain[PC]): Chain[PC]

    This function can be called when the instruction successorPC needs to be scheduled.

    This function can be called when the instruction successorPC needs to be scheduled. The function will test if the instruction is already scheduled and – if so – returns the given worklist. Otherwise the instruction is scheduled in the correct (subroutine-)context.

    Attributes
    protected[this]
    Definition Classes
    CoreDomainFunctionality
  33. def summarize(pc: PC, values: Iterable[DomainValue]): DomainValue

    Creates a summary of the given domain values by summarizing and joining the given values.

    Creates a summary of the given domain values by summarizing and joining the given values. For the precise details regarding the calculation of a summary see Value.summarize(...).

    pc

    The program counter that will be used for the summary value if a new value is returned that abstracts over/summarizes the given values.

    values

    An Iterable over one or more values.

    Definition Classes
    ValuesDomain
    Note

    The current algorithm is generic and should satisfy most needs, but it is not very efficient. However, it should be easy to tailor it for a specific domain/domain values, if need be.

  34. final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
    AnyRef
  35. def toString(): String
    Definition Classes
    AnyRef → Any
  36. def typeOfValue(value: DomainValue): TypeInformation

    Returns the type(type bounds) of the given value.

    Returns the type(type bounds) of the given value.

    In general a single value can have multiple type bounds which depend on the control flow. However, all types that the value represents must belong to the same computational type category. I.e., it is possible that the value either has the type "NullPointerException or IllegalArgumentException", but it will never have – at the same time – the (Java) types int and long. Furthermore, it is possible that the returned type(s) is(are) only an upper bound of the real type unless the type is a primitive type.

    This default implementation always returns org.opalj.ai.UnknownType.

    Implementing typeOfValue

    This method is typically not implemented by a single Domain trait/object, but is instead implemented collaboratively by all domains that implement the semantics of certain values. To achieve that, other Domain traits that implement a concrete domain's semantics have to abstract override this method and only return the value's type if the domain knows anything about the type. If a method that overrides this method has no knowledge about the given value, it should delegate this call to its super method.

    Example

    trait FloatValues extends Domain[...] {
      ...
        abstract override def typeOfValue(value: DomainValue): TypesAnswer =
        value match {
          case r: FloatValue ⇒ IsFloatValue
          case _             ⇒ super.typeOfValue(value)
        }
    }
    Definition Classes
    ValuesDomain
  37. def updateMemoryLayout(oldValue: DomainValue, newValue: DomainValue, operands: Operands, locals: Locals): (Operands, Locals)

    Replaces all occurrences of oldValue (using reference-quality) with newValue.

    Replaces all occurrences of oldValue (using reference-quality) with newValue. If no occurrences are found, the original operands and locals data structures are returned.

    Definition Classes
    CoreDomainFunctionality
  38. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  39. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  40. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @native() @throws( ... )

Inherited from CoreDomainFunctionality

Inherited from SubroutinesDomain

Inherited from ValuesDomain

Inherited from AnyRef

Inherited from Any

Ungrouped