trait ValuesDomain extends AnyRef
Defines the concept of a value in a Domain
.
- Self Type
- ValuesDomain
- Source
- ValuesDomain.scala
- See also
Domain For an explanation of the underlying concepts and ideas.
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Type Members
- 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 typeDomainValue
is refined. - abstract type DomainReferenceValue >: Null <: ReferenceValue with DomainTypedValue[ReferenceType]
- 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 theValue
trait nor theReturnAddressValue
trait was refined) it is sufficient to write:type DomainReturnAddressValue = ReturnAddressValue
- abstract type DomainReturnAddressValues <: ReturnAddressValues with DomainValue
- abstract type DomainTypedValue[+T <: Type] >: Null <: DomainValue
- 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 fromDomain
and which extendDomain
'sValue
trait. - type ExceptionValue = DomainReferenceValue
A simple type alias of the type
DomainValue
; used to facilitate comprehension. - type ExceptionValues = Iterable[ExceptionValue]
A type alias for
Iterable
s ofExceptionValue
s; used to facilitate comprehension. - class IllegalValue extends Value with IsIllegalValue
Represents a value that has no well defined state/type.
Represents a value that has no well defined state/type. Such values are either the result of a join of two incompatible values or if the variable was identified as being dead.
IllegalValue
's are only found in registers (in the locals).- Attributes
- protected
- See also
org.opalj.ai.Domain.Value for further details.
- type Locals = collection.mutable.Locals[DomainValue]
An instruction's current register values/locals are represented using an array.
- type LocalsArray = Array[Locals]
- type Operands = List[DomainValue]
An instruction's operands are represented using a list where the first element of the list represents the top level operand stack value.
- type OperandsArray = Array[Operands]
- trait RETValue extends Value with IsReturnAddressValue
- trait ReferenceValue extends TypedValue[ReferenceType] with IsReferenceValue
- 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).
- 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 theValue
trait should be refined, all additional methods may – from the point-of-view of OPAL-AI – just throw anUnsupportedOperationException
as these additional methods will never be called by the OPAL-AI.
- class ReturnAddressValues extends RETValue
A collection of (not further stored) return address values.
A collection of (not further stored) return address values. Primarily used when we join the executions of subroutines.
- trait TypedValue[+T <: Type] extends Value with KnownTypedValue
- trait Value extends ValueInformation
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 onValue
. Instead they should useDomainValue
as otherwise extensibility of aDomain
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 liketrait 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 typeDomainType
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.
- Note
OPAL does not rely on any special equality semantics w.r.t. values and never directly or indirectly calls a
Value
'sequals
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 arbitraryInteger
value has to returntrue
if the domain value with which it is compared also represents an arbitraryInteger
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 theAnIntegervalue
from some otherAnIntegerValue
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.
Abstract Value Members
- abstract val DomainReferenceValueTag: 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
- implicit abstract val DomainValueTag: 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 abstractval
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.) - abstract def InitializedDomainValue(origin: ValueOrigin, vi: ValueInformation): DomainValue
Creates a domain value from the given value information that represents a properly domain value.
Creates a domain value from the given value information that represents a properly domain value. A representation of a proper value is created even if the value information is provided for an uninitialized value.
- Note
This function is only defined for proper values, i.e., it is not defined for void values or illegal values.
,This method is intended to be overwritten by concrete domains which can represent more information.
- abstract def MetaInformationUpdateIllegalValue: MetaInformationUpdate[DomainIllegalValue]
The result of the merge of two incompatible values has to be reported as a
MetaInformationUpdate[DomainIllegalValue]
. - abstract def ReturnAddressValue(address: Int): DomainReturnAddressValue
Factory method to create an instance of a
ReturnAddressValue
. - abstract val TheIllegalValue: DomainIllegalValue
The singleton instance of the
IllegalValue
. - abstract val TheReturnAddressValues: DomainReturnAddressValues
The singleton instance of
ReturnAddressValues
- implicit abstract def classHierarchy: ClassHierarchy
This project's class hierarchy.
This project's class hierarchy.
Usually, just a redirect to the
Project
's class hierarchy or the default class hierarchy.
Concrete Value Members
- final def !=(arg0: Any): Boolean
- Definition Classes
- AnyRef → Any
- final def ##: Int
- Definition Classes
- AnyRef → Any
- final def ==(arg0: Any): Boolean
- Definition Classes
- AnyRef → Any
- final def StructuralUpdateIllegalValue: StructuralUpdate[Nothing]
The result of merging two values should never be reported as a
StructuralUpdate
if the computed value is anIllegalValue
.The result of merging two values should never be reported as a
StructuralUpdate
if the computed value is anIllegalValue
. The JVM semantics guarantee that the value will not be used and, hence, continuing the interpretation is meaningless.- Note
This method is solely defined for documentation purposes and to catch implementation errors early on.
- final def asInstanceOf[T0]: T0
- Definition Classes
- Any
- def clone(): AnyRef
- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.CloneNotSupportedException]) @native() @IntrinsicCandidate()
- final def eq(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef
- def equals(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef → Any
- final def getClass(): Class[_ <: AnyRef]
- Definition Classes
- AnyRef → Any
- Annotations
- @native() @IntrinsicCandidate()
- def hashCode(): Int
- Definition Classes
- AnyRef → Any
- Annotations
- @native() @IntrinsicCandidate()
- final def isASubtypeOf(subtype: ReferenceType, supertype: ReferenceType): Answer
Tests if
subtype
is known to be subtype ofsupertype
.Tests if
subtype
is known to be subtype ofsupertype
. See org.opalj.br.ClassHierarchy'sisSubtypeOf
method for details. - final def isInstanceOf[T0]: Boolean
- Definition Classes
- Any
- final def isSubtypeOf(subtype: ReferenceType, supertype: ReferenceType): Boolean
Tests if
subtype
is known to be subtype ofsupertype
.Tests if
subtype
is known to be subtype ofsupertype
. See org.opalj.br.ClassHierarchy'sisSubtypeOf
method for details. - def mergeDomainValues(pc: Int, v1: DomainValue, v2: DomainValue): DomainValue
Merges the given domain value
v1
with the domain valuev2
and returns the merged value which isv1
ifv1
is an abstraction ofv2
,v2
ifv2
is an abstraction ofv1
or some other value if a new value is computed that abstracts over both values.Merges the given domain value
v1
with the domain valuev2
and returns the merged value which isv1
ifv1
is an abstraction ofv2
,v2
ifv2
is an abstraction ofv1
or some other value if a new value is computed that abstracts over both values.This operation is commutative.
- final def ne(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef
- final def notify(): Unit
- Definition Classes
- AnyRef
- Annotations
- @native() @IntrinsicCandidate()
- final def notifyAll(): Unit
- Definition Classes
- AnyRef
- Annotations
- @native() @IntrinsicCandidate()
- def properties(pc: PC, propertyToString: (AnyRef) => String = p => p.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.
Domain
s that define (additional) properties should (abstract
)override
this method and should return a textual representation of the property. - def summarize(pc: Int, 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 seeValue.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.
- 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.
- final def synchronized[T0](arg0: => T0): T0
- Definition Classes
- AnyRef
- def toString(): String
- Definition Classes
- AnyRef → Any
- final def wait(arg0: Long, arg1: Int): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
- final def wait(arg0: Long): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
- final def wait(): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
Deprecated Value Members
- def finalize(): Unit
- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.Throwable]) @Deprecated
- Deprecated