Trait

org.opalj.ai.domain.l0.TypeLevelIntegerValues

ShortValue

Related Doc: package TypeLevelIntegerValues

Permalink

trait ShortValue extends (TypeLevelIntegerValues.this)#ComputationalTypeIntegerValue[ShortType] with IsShortValue[(TypeLevelIntegerValues.this)#ShortValue]

Self Type
(TypeLevelIntegerValues.this)#ShortValue with (TypeLevelIntegerValues.this)#DomainTypedValue[ShortType]
Source
TypeLevelIntegerValues.scala
Linear Supertypes
IsShortValue[(TypeLevelIntegerValues.this)#ShortValue], IsPrimitiveValue[ShortType, (TypeLevelIntegerValues.this)#ShortValue], (TypeLevelIntegerValues.this)#ComputationalTypeIntegerValue[ShortType], (TypeLevelIntegerValues.this)#TypedValue[ShortType], KnownType, TypeInformation, (TypeLevelIntegerValues.this)#Value, AnyRef, Any
Known Subclasses
Ordering
  1. Alphabetic
  2. By Inheritance
Inherited
  1. ShortValue
  2. IsShortValue
  3. IsPrimitiveValue
  4. ComputationalTypeIntegerValue
  5. TypedValue
  6. KnownType
  7. TypeInformation
  8. Value
  9. AnyRef
  10. Any
  1. Hide All
  2. Show All
Visibility
  1. Public
  2. All

Abstract Value Members

  1. abstract def doJoin(pc: PC, value: (TypeLevelIntegerValues.this)#DomainValue): Update[(TypeLevelIntegerValues.this)#DomainValue]

    Permalink

    Joins this value and the given value.

    Joins this value and the given value.

    Join is called whenever an instruction is evaluated more than once and, hence, the values found on the paths need to be joined. This method is, however, only called if the two values are two different objects ((this ne value) === true), but both values have the same computational type.

    This basically implements the join operator of complete lattices.

    Example

    For example, joining a DomainValue that represents the integer value 0 with a DomainValue that represents the integer value 1 may return a new DomainValue that precisely captures the range [0..1] or that captures all positive integer values or just some integer value.

    Contract

    this value is always the value that was previously used to perform subsequent computations/analyses. Hence, if this value subsumes the given value, the result has to be either NoUpdate or a MetaInformationUpdate. In case that the given value subsumes this value, the result has to be a StructuralUpdate with the given value as the new value. Hence, this join operation is not commutative. If a new (more abstract) abstract value is created that represents both values the result always has to be a StructuralUpdate. If the result is a StructuralUpdate the framework will continue with the interpretation.

    The termination of the abstract interpretation directly depends on the fact that at some point all (abstract) values are fixed and don't change anymore. Hence, it is important that the type of the update is only a org.opalj.ai.StructuralUpdate if the value has changed in a way relevant for future computations/analyses involving this value. In other words, when two values are joined it has to be ensured that no fall back to a previous value occurs. E.g., if you join the existing integer value 0 and the given value 1 and the result would be 1, then it must be ensured that a subsequent join with the value 0 will not result in the value 0 again.

    Conceptually, the join of an object with itself has to return the object itself. Note, that this is a conceptual requirement as such a call (this.doJoin(..,this)) will not be performed by the abstract interpretation framework; this case is handled by the join method. However, if the join object is also used by the implementation of the domain itself, it may be necessary to explicitly handle self-joins.

    Performance

    In general, the domain should try to minimize the number of objects that it uses to represent values. That is, two values that are conceptually equal should – whenever possible – use only one object. This has a significant impact on functions such as join.

    pc

    The program counter of the instruction where the paths converge.

    value

    The "new" domain value with which this domain value should be joined. The given value and this value are guaranteed to have the same computational type, but are not reference equal.

    Attributes
    protected[this]
    Definition Classes
    Value

Concrete Value Members

  1. final def !=(arg0: Any): Boolean

    Permalink
    Definition Classes
    AnyRef → Any
  2. final def ##(): Int

    Permalink
    Definition Classes
    AnyRef → Any
  3. final def ==(arg0: Any): Boolean

    Permalink
    Definition Classes
    AnyRef → Any
  4. def abstractsOver(other: (TypeLevelIntegerValues.this)#DomainValue): Boolean

    Permalink

    Returns true iff the abstract state represented by this value abstracts over the state of the given value.

    Returns true iff the abstract state represented by this value abstracts over the state of the given value. In other words if every possible runtime value represented by the given value is also represented by this value.

    The abstract state generally encompasses every information that would be considered during a join of this value and the other value and that could lead to an Update.

    This method is reflexive, I.e., every value abstracts over itself.

    TheIllegalValue only abstracts over itself.

    Definition Classes
    Value
    Note

    abstractsOver is only defined for comparable values where both values have the same computational type.

    Implementation

    The default implementation relies on this domain value's join method. Overriding this method is, hence, primarily meaningful for performance reasons.

    See also

    isMorePreciseThan

  5. def adapt(target: TargetDomain, vo: ValueOrigin): (target)#DomainValue

    Permalink

    Adapts this value to the given domain (default: throws a domain exception that adaptation is not supported).

    Adapts this value to the given domain (default: throws a domain exception that adaptation is not supported). This method needs to be overridden by concrete Value classes to support the adaptation for a specific domain.

    Supporting the adapt method is primarily necessary when you want to analyze a method that is called by the currently analyzed method and you need to adapt this domain's values (the actual parameters of the method) to the domain used for analyzing the called method.

    Additionally, the adapt method is OPAL's main mechanism to enable dynamic domain-adaptation. I.e., to make it possible to change the abstract domain at runtime if the analysis time takes too long using a (more) precise domain.

    Definition Classes
    ShortValueValue
    Note

    The abstract interpretation framework does not use/call this method. This method is solely predefined to facilitate the development of project-wide analyses.

  6. def asDomainReferenceValue: (TypeLevelIntegerValues.this)#DomainReferenceValue

    Permalink

    returns

    The represented reference value if and only if this value represents a reference value.

    Definition Classes
    Value
  7. final def asInstanceOf[T0]: T0

    Permalink
    Definition Classes
    Any
  8. def clone(): AnyRef

    Permalink
    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  9. final def computationalType: ComputationalType

    Permalink

    The computational type of the value.

    The computational type of the value.

    The precise computational type is needed by the framework to calculate the effect of generic stack manipulation instructions (e.g., DUP_... and SWAP) on the stack as well as to calculate the jump targets of RET instructions and to determine which values are actually copied by, e.g., the dup_XX instructions.

    Definition Classes
    ComputationalTypeIntegerValueValue
    Note

    The computational type has to be precise/correct.

  10. final def eq(arg0: AnyRef): Boolean

    Permalink
    Definition Classes
    AnyRef
  11. def equals(arg0: Any): Boolean

    Permalink
    Definition Classes
    AnyRef → Any
  12. def finalize(): Unit

    Permalink
    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( classOf[java.lang.Throwable] )
  13. final def getClass(): Class[_]

    Permalink
    Definition Classes
    AnyRef → Any
  14. def hashCode(): Int

    Permalink
    Definition Classes
    AnyRef → Any
  15. final def isInstanceOf[T0]: Boolean

    Permalink
    Definition Classes
    Any
  16. def isMorePreciseThan(other: (TypeLevelIntegerValues.this)#DomainValue): Boolean

    Permalink

    Returns true iff the abstract state represented by this value is strictly more precise than the state of the given value.

    Returns true iff the abstract state represented by this value is strictly more precise than the state of the given value. In other words if every possible runtime value represented by this value is also represented by the given value, but both are not equal; in other words, this method is irreflexive.

    The considered abstract state generally encompasses every information that would be considered during a join of this value and the other value and that could lead to a StructuralUpdate.

    other

    Another DomainValue with the same computational type as this value. (The IllegalValue has no computational type and, hence, a comparison with an IllegalValue is not well defined.)

    Definition Classes
    Value
    Note

    It is recommended to overwrite this method for performance reasons, as the default implementation relies on join.

    See also

    abstractsOver

  17. final def isPrimitiveValue: Boolean

    Permalink

    True in case of a value with primitive type; undefined if the type is unknown.

    True in case of a value with primitive type; undefined if the type is unknown.

    Definition Classes
    IsPrimitiveValueTypeInformation
  18. final def isReferenceValue: Boolean

    Permalink

    True if the value has a reference type; undefined if the type is unknown.

    True if the value has a reference type; undefined if the type is unknown.

    Definition Classes
    IsPrimitiveValueTypeInformation
  19. final def isUnknownValue: Boolean

    Permalink

    Returns true if no type information is available.

    Returns true if no type information is available.

    Definition Classes
    KnownTypeTypeInformation
  20. def join(pc: PC, that: (TypeLevelIntegerValues.this)#DomainValue): Update[(TypeLevelIntegerValues.this)#DomainValue]

    Permalink

    Checks that the given value and this value are compatible with regard to its computational type and – if so – calls doJoin.

    Checks that the given value and this value are compatible with regard to its computational type and – if so – calls doJoin.

    See doJoin(PC,DomainValue) for details.

    pc

    The program counter of the instruction where the paths converge.

    that

    The "new" domain value with which this domain value should be joined. The caller has to ensure that the given value and this value are guaranteed to be two different objects.

    returns

    MetaInformationUpdateIllegalValue or the result of calling doJoin.

    Definition Classes
    Value
    Note

    It is in general not recommended/needed to override this method.

  21. final def ne(arg0: AnyRef): Boolean

    Permalink
    Definition Classes
    AnyRef
  22. final def notify(): Unit

    Permalink
    Definition Classes
    AnyRef
  23. final def notifyAll(): Unit

    Permalink
    Definition Classes
    AnyRef
  24. final def primitiveType: ShortType

    Permalink
    Definition Classes
    IsShortValueIsPrimitiveValue
  25. def summarize(pc: PC): (TypeLevelIntegerValues.this)#DomainValue

    Permalink

    Creates a summary of this value.

    Creates a summary of this value.

    In general, creating a summary of a value may be useful/required for values that are potentially returned by a called method and which will then be used by the calling method. For example, it may be useful to precisely track the flow of values within a method to be able to distinguish between all sources of a value (E.g., to be able to distinguish between a NullPointerException created by instruction A and another one created by instruction B (A != B).) However, from the caller perspective it may be absolutely irrelevant where/how the value was created in the called method and, hence, keeping all information would just waste memory and a summary may be sufficient.

    Definition Classes
    ComputationalTypeIntegerValueValue
    Note

    This method is predefined to facilitate the development of project-wide analyses.

  26. final def synchronized[T0](arg0: ⇒ T0): T0

    Permalink
    Definition Classes
    AnyRef
  27. def toString(): String

    Permalink
    Definition Classes
    AnyRef → Any
  28. def valueType: Option[ShortType]

    Permalink
    Definition Classes
    IsPrimitiveValue
  29. final def wait(): Unit

    Permalink
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  30. final def wait(arg0: Long, arg1: Int): Unit

    Permalink
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  31. final def wait(arg0: Long): Unit

    Permalink
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )

Inherited from IsShortValue[(TypeLevelIntegerValues.this)#ShortValue]

Inherited from IsPrimitiveValue[ShortType, (TypeLevelIntegerValues.this)#ShortValue]

Inherited from (TypeLevelIntegerValues.this)#ComputationalTypeIntegerValue[ShortType]

Inherited from (TypeLevelIntegerValues.this)#TypedValue[ShortType]

Inherited from KnownType

Inherited from TypeInformation

Inherited from (TypeLevelIntegerValues.this)#Value

Inherited from AnyRef

Inherited from Any

Ungrouped