Package it.unive.lisa.analysis.nonrelational

Class VariableLift<M extends VariableLift<M,E,T>,E extends SymbolicExpression,T extends NonRelationalElement<T,E,M>>

java.lang.Object

it.unive.lisa.analysis.lattices.FunctionalLattice<M,Identifier,T>

it.unive.lisa.analysis.nonrelational.VariableLift<M,E,T>

Type Parameters:

M - the concrete type of the lift

E - the type of expressions that this domain can evaluate

T - the concrete instance of the NonRelationalElement whose instances are mapped in this environment

All Implemented Interfaces:

BaseLattice<M>, Lattice<M>, ScopedObject<M>, SemanticDomain<M,E,Identifier>, StructuredObject, java.lang.Iterable<java.util.Map.Entry<Identifier,T>>

Direct Known Subclasses:

Environment, InferenceSystem

public abstract class VariableLift<M extends VariableLift<M,E,T>,E extends SymbolicExpression,T extends NonRelationalElement<T,E,M>>
extends FunctionalLattice<M,Identifier,T>
implements SemanticDomain<M,E,Identifier>

A SemanticDomain implemented as a lift for a NonRelationalElements, that maps Identifiers to instances of such domain. This is a FunctionalLattice, that is, it implements a function mapping keys (identifiers) to values (instances of the domain), and lattice operations are automatically lifted for individual elements of the environment if they are mapped to the same key.

Nested Class Summary

Nested classes/interfaces inherited from class it.unive.lisa.analysis.lattices.FunctionalLattice

FunctionalLattice.FunctionalLift<V extends Lattice<V>>, FunctionalLattice.KeyFunctionalLift<K>

Field Summary

Fields inherited from class it.unive.lisa.analysis.lattices.FunctionalLattice

function, lattice

Fields inherited from interface it.unive.lisa.analysis.Lattice

BOTTOM_STRING, TOP_STRING

Constructor Summary

Constructors

Constructor	Description
VariableLift(T domain)	Builds an empty lift.
VariableLift(T domain, java.util.Map<Identifier,T> function)	Builds a lift containing the given mapping.

Method Summary

Modifier and Type	Method	Description
M	forgetIdentifier(Identifier id)	Forgets an Identifier.
M	forgetIdentifiersIf(java.util.function.Predicate<Identifier> test)	Forgets all Identifiers that match the given predicate.
boolean	knowsIdentifier(Identifier id)	Yields true if this instance is currently tracking abstract information for the given identifier.
java.util.Set<Identifier>	lubKeys(java.util.Set<Identifier> k1, java.util.Set<Identifier> k2)	Yields the union of the keys between k1 and k2.
M	popScope(ScopeToken scope)	Pops the scope identified by the given token from this object.
M	pushScope(ScopeToken scope)	Pushes a new scope, identified by the give token, in this object.
Satisfiability	satisfies(E expression, ProgramPoint pp, SemanticOracle oracle)	Checks if the given expression is satisfied by the abstract values of this domain, returning an instance of Satisfiability.
T	stateOfUnknown(Identifier key)	Yields the value that should be returned by FunctionalLattice.getState(Object) whenever the given key is not present in this map.

Methods inherited from class it.unive.lisa.analysis.lattices.FunctionalLattice

equals, functionalLift, getKeys, getMap, getOtDefault, getState, getValues, glbAux, glbKeys, hashCode, isBottom, isTop, iterator, lessOrEqualAux, lubAux, mk, mkNewFunction, narrowingAux, putState, representation, toString, wideningAux

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface it.unive.lisa.analysis.BaseLattice

glb, lessOrEqual, lub, narrowing, widening

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Methods inherited from interface it.unive.lisa.analysis.Lattice

bottom, top

Methods inherited from interface it.unive.lisa.analysis.SemanticDomain

assign, assume, forgetIdentifiers, getAllDomainInstances, getDomainInstance, smallStepSemantics

Methods inherited from interface it.unive.lisa.util.representation.StructuredObject

representation

Constructor Detail

VariableLift

public VariableLift(T domain)

Builds an empty lift.

Parameters:

domain - a singleton instance to be used during semantic operations to retrieve top and bottom values

VariableLift

public VariableLift(T domain,
                    java.util.Map<Identifier,T> function)

Builds a lift containing the given mapping. If function is null, the new lift is the top lift if lattice.isTop() holds, and it is the bottom lift if lattice.isBottom() holds.

Parameters:

domain - a singleton instance to be used during semantic operations to retrieve top and bottom values

function - the function representing the mapping contained in the new lift; can be null

Method Detail

satisfies

public Satisfiability satisfies(E expression,
                                ProgramPoint pp,
                                SemanticOracle oracle)
                         throws SemanticException

Description copied from interface: SemanticDomain

Checks if the given expression is satisfied by the abstract values of this domain, returning an instance of Satisfiability.

Specified by:

satisfies in interface SemanticDomain<M extends VariableLift<M,E,T>,E extends SymbolicExpression,T extends NonRelationalElement<T,E,M>>

Parameters:

expression - the expression whose satisfiability is to be evaluated

pp - the program point that where this operation is being evaluated

oracle - the oracle for inter-domain communication

Returns:

Satisfiability.SATISFIED is the expression is satisfied by the values of this domain, Satisfiability.NOT_SATISFIED if it is not satisfied, or Satisfiability.UNKNOWN if it is either impossible to determine if it satisfied, or if it is satisfied by some values and not by some others (this is equivalent to a TOP boolean value)

Throws:

SemanticException - if an error occurs during the computation

pushScope

public M pushScope(ScopeToken scope)
            throws SemanticException

Description copied from interface: ScopedObject

Pushes a new scope, identified by the give token, in this object. This causes all variables not associated with a scope (and thus visible) to be mapped to the given scope and hidden away, until the scope is popped with ScopedObject.popScope(ScopeToken).

Specified by:

pushScope in interface ScopedObject<M extends VariableLift<M,E,T>>

Parameters:

scope - the token identifying the scope to push

Returns:

a copy of this object where the local unscoped variables have been hidden

Throws:

SemanticException - if an error occurs during the computation

popScope

public M popScope(ScopeToken scope)
           throws SemanticException

Description copied from interface: ScopedObject

Pops the scope identified by the given token from this object. This causes all the visible variables (i.e. that are not mapped to a scope) to be removed, while the local variables that were associated to the given scope token (and thus hidden) will become visible again.

Specified by:

popScope in interface ScopedObject<M extends VariableLift<M,E,T>>

Parameters:

scope - the token of the scope to be restored

Returns:

a copy of this object where the local variables have been removed, while the variables mapped to the given scope are visible again

Throws:

SemanticException - if an error occurs during the computation

forgetIdentifier

public M forgetIdentifier(Identifier id)
                   throws SemanticException

Description copied from interface: SemanticDomain

Forgets an Identifier. This means that all information regarding the given id will be lost. This method should be invoked whenever an identifier gets out of scope.

Specified by:

forgetIdentifier in interface SemanticDomain<M extends VariableLift<M,E,T>,E extends SymbolicExpression,T extends NonRelationalElement<T,E,M>>

Parameters:

id - the identifier to forget

Returns:

the semantic domain without information about the given id

Throws:

SemanticException - if an error occurs during the computation

forgetIdentifiersIf

public M forgetIdentifiersIf(java.util.function.Predicate<Identifier> test)
                      throws SemanticException

Description copied from interface: SemanticDomain

Forgets all Identifiers that match the given predicate. This means that all information regarding the those identifiers will be lost. This method should be invoked whenever an identifier gets out of scope.

Specified by:

forgetIdentifiersIf in interface SemanticDomain<M extends VariableLift<M,E,T>,E extends SymbolicExpression,T extends NonRelationalElement<T,E,M>>

Parameters:

test - the test to identify the targets of the removal

Returns:

the semantic domain without information about the ids

Throws:

SemanticException - if an error occurs during the computation

lubKeys

public java.util.Set<Identifier> lubKeys(java.util.Set<Identifier> k1,
                                         java.util.Set<Identifier> k2)
                                  throws SemanticException

Description copied from class: FunctionalLattice

Yields the union of the keys between k1 and k2.

Overrides:

lubKeys in class FunctionalLattice<M extends VariableLift<M,E,T>,Identifier,T extends NonRelationalElement<T,E,M>>

Parameters:

k1 - the first key set

k2 - the second key set

Returns:

the union between k1 and k2

Throws:

SemanticException - if something goes wrong while lifting the keys

stateOfUnknown

public T stateOfUnknown(Identifier key)

Description copied from class: FunctionalLattice

Yields the value that should be returned by FunctionalLattice.getState(Object) whenever the given key is not present in this map.

Specified by:

stateOfUnknown in class FunctionalLattice<M extends VariableLift<M,E,T>,Identifier,T extends NonRelationalElement<T,E,M>>

Parameters:

key - the key that is missing

Returns:

the lattice element for keys not in the mapping

knowsIdentifier

public boolean knowsIdentifier(Identifier id)

Description copied from interface: SemanticDomain

Yields true if this instance is currently tracking abstract information for the given identifier.

Specified by:

knowsIdentifier in interface SemanticDomain<M extends VariableLift<M,E,T>,E extends SymbolicExpression,T extends NonRelationalElement<T,E,M>>

Parameters:

id - the identifier

Returns:

whether or not this domain knows about id