Package it.unive.lisa.analysis.nonrelational.inference

Class InferenceSystem<T extends InferredValue<T>>

java.lang.Object

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

it.unive.lisa.analysis.nonrelational.VariableLift<InferenceSystem<T>,ValueExpression,T>

it.unive.lisa.analysis.nonrelational.inference.InferenceSystem<T>

Type Parameters:

T - the type of InferredValue in this inference system

All Implemented Interfaces:

BaseLattice<InferenceSystem<T>>, Lattice<InferenceSystem<T>>, ScopedObject<InferenceSystem<T>>, SemanticDomain<InferenceSystem<T>,ValueExpression,Identifier>, ValueDomain<InferenceSystem<T>>, ValueOracle, StructuredObject, java.lang.Iterable<java.util.Map.Entry<Identifier,T>>

public class InferenceSystem<T extends InferredValue<T>>
extends VariableLift<InferenceSystem<T>,ValueExpression,T>
implements ValueDomain<InferenceSystem<T>>

An inference system that model standard derivation systems. An inference system is a VariableLift that works on InferredValues, and that exposes an execution state (getExecutionState()).

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
InferenceSystem(InferenceSystem<T> other, T state)	Builds an inference system identical to the given one, except for the execution state that will be set to the given one.
InferenceSystem(T domain)	Builds an empty inference system.
InferenceSystem(T domain, java.util.Map<Identifier,T> function, T state)	Builds an environment containing the given mapping.

Method Summary

Modifier and Type	Method	Description
InferenceSystem<T>	assign(Identifier id, ValueExpression expression, ProgramPoint pp, SemanticOracle oracle)	Yields a copy of this domain, where id has been assigned to value.
InferenceSystem<T>	assume(ValueExpression expression, ProgramPoint src, ProgramPoint dest, SemanticOracle oracle)	Yields a copy of this domain, modified by assuming that the given expression holds.
InferenceSystem<T>	bottom()	Yields the bottom element of this lattice.
boolean	equals(java.lang.Object obj)
T	eval(ValueExpression expression, ProgramPoint pp, SemanticOracle oracle)	Evaluates the given expression to an abstract value.
T	getExecutionState()	Yields the execution state (also called program counter), that might change when evaluating an expression.
InferenceSystem<T>	glbAux(InferenceSystem<T> other)	Performs the greatest lower bound operation between this lattice element and the given one, assuming that base cases have already been handled.
int	hashCode()
boolean	isBottom()	Yields true if and only if this object represents the bottom of the lattice.
boolean	isTop()	Yields true if and only if this object represents the top of the lattice.
boolean	lessOrEqualAux(InferenceSystem<T> other)	Yields true if and only if this lattice element is in relation with (usually represented through ≤) the given one, assuming that base cases have already been handled.
InferenceSystem<T>	lubAux(InferenceSystem<T> other)	Performs the least upper bound operation between this lattice element and the given one, assuming that base cases have already been handled.
InferenceSystem<T>	mk(T lattice, java.util.Map<Identifier,T> function)	Builds a instance of this class from the given lattice instance and the given mapping.
InferenceSystem<T>	narrowingAux(InferenceSystem<T> other)	Performs the narrowing operation between this lattice element and the given one, assuming that base cases have already been handled.
StructuredRepresentation	representation()	Yields a StructuredRepresentation of the information contained in this object's instance.
InferenceSystem<T>	smallStepSemantics(ValueExpression expression, ProgramPoint pp, SemanticOracle oracle)	Yields a copy of this domain, that has been modified accordingly to the semantics of the given expression.
InferenceSystem<T>	top()	Yields the top element of this lattice.
InferenceSystem<T>	wideningAux(InferenceSystem<T> other)	Performs the widening operation between this lattice element and the given one, assuming that base cases have already been handled.

Methods inherited from class it.unive.lisa.analysis.nonrelational.VariableLift

forgetIdentifier, forgetIdentifiersIf, knowsIdentifier, lubKeys, popScope, pushScope, satisfies, stateOfUnknown

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

functionalLift, getKeys, getMap, getOtDefault, getState, getValues, glbKeys, iterator, mkNewFunction, putState, toString

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.ScopedObject

popScope, pushScope

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

forgetIdentifier, forgetIdentifiers, forgetIdentifiersIf, getAllDomainInstances, getDomainInstance, knowsIdentifier, satisfies

Methods inherited from interface it.unive.lisa.analysis.value.ValueDomain

applyReplacement

Constructor Detail

InferenceSystem

public InferenceSystem(T domain)

Builds an empty inference system.

Parameters:

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

InferenceSystem

public InferenceSystem(InferenceSystem<T> other,
                       T state)

Builds an inference system identical to the given one, except for the execution state that will be set to the given one.

Parameters:

other - the inference system to copy

state - the new execution state

InferenceSystem

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

Builds an environment containing the given mapping. If function is null, the new environment is the top environment if lattice.isTop() holds, and it is the bottom environment 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 environment; can be null

state - the execution state after the last computed expression

Method Detail

mk

public InferenceSystem<T> mk(T lattice,
                             java.util.Map<Identifier,T> function)

Description copied from class: FunctionalLattice

Builds a instance of this class from the given lattice instance and the given mapping.

Specified by:

mk in class FunctionalLattice<InferenceSystem<T extends InferredValue<T>>,Identifier,T extends InferredValue<T>>

Parameters:

lattice - an instance of lattice to be used during semantic operations to retrieve top and bottom values

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

Returns:

a new instance of this class

assign

public InferenceSystem<T> assign(Identifier id,
                                 ValueExpression expression,
                                 ProgramPoint pp,
                                 SemanticOracle oracle)
                          throws SemanticException

Description copied from interface: SemanticDomain

Yields a copy of this domain, where id has been assigned to value.

Specified by:

assign in interface SemanticDomain<InferenceSystem<T extends InferredValue<T>>,ValueExpression,Identifier>

Parameters:

id - the identifier to assign the value to

expression - the expression to assign

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

oracle - the oracle for inter-domain communication

Returns:

a copy of this domain, modified by the assignment

Throws:

SemanticException - if an error occurs during the computation

getExecutionState

public T getExecutionState()

Yields the execution state (also called program counter), that might change when evaluating an expression.

Returns:

the execution state

smallStepSemantics

public InferenceSystem<T> smallStepSemantics(ValueExpression expression,
                                             ProgramPoint pp,
                                             SemanticOracle oracle)
                                      throws SemanticException

Description copied from interface: SemanticDomain

Yields a copy of this domain, that has been modified accordingly to the semantics of the given expression.

Specified by:

smallStepSemantics in interface SemanticDomain<InferenceSystem<T extends InferredValue<T>>,ValueExpression,Identifier>

Parameters:

expression - the expression whose semantics need to be computed

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

oracle - the oracle for inter-domain communication

Returns:

a copy of this domain, modified accordingly to the semantics of expression

Throws:

SemanticException - if an error occurs during the computation

assume

public InferenceSystem<T> assume(ValueExpression expression,
                                 ProgramPoint src,
                                 ProgramPoint dest,
                                 SemanticOracle oracle)
                          throws SemanticException

Description copied from interface: SemanticDomain

Yields a copy of this domain, modified by assuming that the given expression holds. It is required that the returned domain is in relation with this one. A safe (but imprecise) implementation of this method can always return this.

Specified by:

assume in interface SemanticDomain<InferenceSystem<T extends InferredValue<T>>,ValueExpression,Identifier>

Parameters:

expression - the expression to assume to hold.

src - the program point that where this operation is being evaluated, corresponding to the one that generated the given expression

dest - the program point where the execution will move after the expression has been assumed

oracle - the oracle for inter-domain communication

Returns:

the (optionally) modified copy of this domain

Throws:

SemanticException - if an error occurs during the computation

eval

public T eval(ValueExpression expression,
              ProgramPoint pp,
              SemanticOracle oracle)
       throws SemanticException

Evaluates the given expression to an abstract value.

Parameters:

expression - the expression to evaluate

pp - the program point where the evaluation happens

oracle - the oracle for inter-domain communication

Returns:

the abstract result of the evaluation

Throws:

SemanticException - if an error happens during the evaluation

top

public InferenceSystem<T> top()

Description copied from interface: Lattice

Yields the top element of this lattice. The returned element should be unique across different calls to this method, since Lattice.isTop() uses reference equality by default. If the value returned by this method is not a singleton, override Lattice.isTop() accordingly to provide a coherent test.

Specified by:

top in interface Lattice<T extends InferredValue<T>>

Returns:

the top element

bottom

public InferenceSystem<T> bottom()

Description copied from interface: Lattice

Yields the bottom element of this lattice. The returned element should be unique across different calls to this method, since Lattice.isBottom() uses reference equality by default. If the value returned by this method is not a singleton, override Lattice.isBottom() accordingly to provide a coherent test.

Specified by:

bottom in interface Lattice<T extends InferredValue<T>>

Returns:

the bottom element

isTop

public boolean isTop()

Description copied from class: FunctionalLattice

Yields true if and only if this object represents the top of the lattice. The default implementation of this method uses reference equality between this and the value returned by Lattice.top(), thus assuming that the top element is a singleton. If this is not the case, override this method accordingly to provide a coherent test.

By default, a functional lattice is the top lattice if the underlying lattice's isTop() holds and its function is null.

Specified by:

isTop in interface Lattice<T extends InferredValue<T>>

Overrides:

isTop in class FunctionalLattice<InferenceSystem<T extends InferredValue<T>>,Identifier,T extends InferredValue<T>>

Returns:

true if this is the top of the lattice

isBottom

public boolean isBottom()

Description copied from class: FunctionalLattice

Yields true if and only if this object represents the bottom of the lattice. The default implementation of this method uses reference equality between this and the value returned by Lattice.bottom(), thus assuming that the bottom element is a singleton. If this is not the case, override this method accordingly to provide a coherent test.

By default, a functional lattice is the top lattice if the underlying lattice's isBottom() holds and its function is null.

Specified by:

isBottom in interface Lattice<T extends InferredValue<T>>

Overrides:

isBottom in class FunctionalLattice<InferenceSystem<T extends InferredValue<T>>,Identifier,T extends InferredValue<T>>

Returns:

true if this is the bottom of the lattice

lubAux

public InferenceSystem<T> lubAux(InferenceSystem<T> other)
                          throws SemanticException

Description copied from interface: BaseLattice

Performs the least upper bound operation between this lattice element and the given one, assuming that base cases have already been handled. In particular, it is guaranteed that:

• other is not null
• other is neither top nor bottom
• this is neither top nor bottom
• this and other are not the same object (according both to == and to Object.equals(Object))

Specified by:

lubAux in interface BaseLattice<T extends InferredValue<T>>

Overrides:

lubAux in class FunctionalLattice<InferenceSystem<T extends InferredValue<T>>,Identifier,T extends InferredValue<T>>

Parameters:

other - the other lattice element

Returns:

the least upper bound between this and other

Throws:

SemanticException - if an error occurs during the computation

wideningAux

public InferenceSystem<T> wideningAux(InferenceSystem<T> other)
                               throws SemanticException

Description copied from interface: BaseLattice

Performs the widening operation between this lattice element and the given one, assuming that base cases have already been handled. In particular, it is guaranteed that:

• other is not null
• other is neither top nor bottom
• this is neither top nor bottom
• this and other are not the same object (according both to == and to Object.equals(Object))

The default implementation of this method delegates to BaseLattice.lubAux(BaseLattice), and is thus safe for finite lattices and ACC ones.

Specified by:

wideningAux in interface BaseLattice<T extends InferredValue<T>>

Overrides:

wideningAux in class FunctionalLattice<InferenceSystem<T extends InferredValue<T>>,Identifier,T extends InferredValue<T>>

Parameters:

other - the other lattice element

Returns:

the widening between this and other

Throws:

SemanticException - if an error occurs during the computation

glbAux

public InferenceSystem<T> glbAux(InferenceSystem<T> other)
                          throws SemanticException

Description copied from interface: BaseLattice

Performs the greatest lower bound operation between this lattice element and the given one, assuming that base cases have already been handled. In particular, it is guaranteed that:

• other is not null
• other is neither top nor bottom
• this is neither top nor bottom
• this and other are not the same object (according both to == and to Object.equals(Object))

Specified by:

glbAux in interface BaseLattice<T extends InferredValue<T>>

Overrides:

glbAux in class FunctionalLattice<InferenceSystem<T extends InferredValue<T>>,Identifier,T extends InferredValue<T>>

Parameters:

other - the other lattice element

Returns:

the greatest lower bound between this and other

Throws:

SemanticException - if an error occurs during the computation

narrowingAux

public InferenceSystem<T> narrowingAux(InferenceSystem<T> other)
                                throws SemanticException

Description copied from interface: BaseLattice

Performs the narrowing operation between this lattice element and the given one, assuming that base cases have already been handled. In particular, it is guaranteed that:

• other is not null
• other is neither top nor bottom
• this is neither top nor bottom
• this and other are not the same object (according both to == and to Object.equals(Object))

The default implementation of this method delegates to BaseLattice.glbAux(BaseLattice), and is thus safe for finite lattices and DCC ones.

Specified by:

narrowingAux in interface BaseLattice<T extends InferredValue<T>>

Overrides:

narrowingAux in class FunctionalLattice<InferenceSystem<T extends InferredValue<T>>,Identifier,T extends InferredValue<T>>

Parameters:

other - the other lattice element

Returns:

the narrowing between this and other

Throws:

SemanticException - if an error occurs during the computation

lessOrEqualAux

public boolean lessOrEqualAux(InferenceSystem<T> other)
                       throws SemanticException

Description copied from interface: BaseLattice

Yields true if and only if this lattice element is in relation with (usually represented through ≤) the given one, assuming that base cases have already been handled. In particular, it is guaranteed that:

• other is not null
• other is neither top nor bottom
• this is neither top nor bottom
• this and other are not the same object (according both to == and to Object.equals(Object))

Specified by:

lessOrEqualAux in interface BaseLattice<T extends InferredValue<T>>

Overrides:

lessOrEqualAux in class FunctionalLattice<InferenceSystem<T extends InferredValue<T>>,Identifier,T extends InferredValue<T>>

Parameters:

other - the other lattice element

Returns:

true if and only if that condition holds

Throws:

SemanticException - if an error occurs during the computation

hashCode

public int hashCode()

Specified by:

hashCode in interface BaseLattice<T extends InferredValue<T>>

Overrides:

hashCode in class FunctionalLattice<InferenceSystem<T extends InferredValue<T>>,Identifier,T extends InferredValue<T>>

equals

public boolean equals(java.lang.Object obj)

Specified by:

equals in interface BaseLattice<T extends InferredValue<T>>

Overrides:

equals in class FunctionalLattice<InferenceSystem<T extends InferredValue<T>>,Identifier,T extends InferredValue<T>>

representation

public StructuredRepresentation representation()

Description copied from interface: StructuredObject

Yields a StructuredRepresentation of the information contained in this object's instance.

Specified by:

representation in interface StructuredObject

Overrides:

representation in class FunctionalLattice<InferenceSystem<T extends InferredValue<T>>,Identifier,T extends InferredValue<T>>

Returns:

the representation