Package it.unive.lisa.analysis.nonrelational.value

Class ValueEnvironment<T extends NonRelationalValueDomain<T>>

java.lang.Object

it.unive.lisa.analysis.BaseLattice<F>

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

it.unive.lisa.analysis.nonrelational.Environment<ValueEnvironment<T>,ValueExpression,T,T>

it.unive.lisa.analysis.nonrelational.value.ValueEnvironment<T>

Type Parameters:

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

All Implemented Interfaces:

Lattice<ValueEnvironment<T>>, SemanticDomain<ValueEnvironment<T>,ValueExpression,Identifier>, ValueDomain<ValueEnvironment<T>>, java.lang.Iterable<java.util.Map.Entry<Identifier,T>>

public class ValueEnvironment<T extends NonRelationalValueDomain<T>>
extends Environment<ValueEnvironment<T>,ValueExpression,T,T>
implements ValueDomain<ValueEnvironment<T>>

An environment for a NonRelationalValueDomain, 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. The abstract value computed for the last processed expression is exposed through getValueOnStack().

Nested Class Summary

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

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

Nested classes/interfaces inherited from interface it.unive.lisa.analysis.SemanticDomain

SemanticDomain.Satisfiability

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
ValueEnvironment(T domain)	Builds an empty environment.
ValueEnvironment(T domain, java.util.Map<Identifier,T> function, T stack)	Builds an environment containing the given mapping.

Method Summary

Modifier and Type	Method	Description
ValueEnvironment<T>	assignAux(Identifier id, ValueExpression expression, java.util.Map<Identifier,T> function, T value, T eval, ProgramPoint pp)	Auxiliary function of Environment.assign(Identifier, SymbolicExpression, ProgramPoint) that is invoked after the evaluation of the expression.
ValueEnvironment<T>	assumeSatisfied(T eval)	Assumes that an expression, that evaluated to eval, is always satisfied by this environment.
ValueEnvironment<T>	bottom()	Yields the bottom element of this lattice.
ValueEnvironment<T>	copy()	Copies this environment.
boolean	equals(java.lang.Object obj)
org.apache.commons.lang3.tuple.Pair<T,T>	eval(ValueExpression expression, ProgramPoint pp)	Yields the evaluation of the given expression, happening at the given program point.
T	getValueOnStack()	Yields the computed value of the last SymbolicExpression handled by this domain, either through Environment.assign(Identifier, SymbolicExpression, ProgramPoint) or smallStepSemantics(ValueExpression, ProgramPoint).
ValueEnvironment<T>	glbAux(T lattice, java.util.Map<Identifier,T> function, ValueEnvironment<T> other)	Auxiliary glb operation, invoked after the result has been computed to create the concrete instance of environment.
int	hashCode()
ValueEnvironment<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.
DomainRepresentation	representation()	Yields a DomainRepresentation of the information contained in this domain's instance.
ValueEnvironment<T>	smallStepSemantics(ValueExpression expression, ProgramPoint pp)	Yields a copy of this domain, that has been modified accordingly to the semantics of the given expression.
ValueEnvironment<T>	top()	Yields the top element of this lattice.

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

assign, assume, forgetIdentifier, forgetIdentifiersIf, glb, lubKeys, popScope, pushScope, satisfies

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

functionalLift, getKeys, getMap, getState, getValues, glbKeys, isBottom, isTop, iterator, lessOrEqualAux, lubAux, mkNewFunction, putState, toString, wideningAux

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

lessOrEqual, lub, widening

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

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

isBottom, isTop, lessOrEqual, lub, widening

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

assign, assume, forgetIdentifier, forgetIdentifiers, forgetIdentifiersIf, getDomainInstance, popScope, pushScope, satisfies

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

applySubstitution

Constructor Detail

ValueEnvironment

public ValueEnvironment(T domain)

Builds an empty environment.

Parameters:

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

ValueEnvironment

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

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

stack - the abstract value for the last computed expression, that is left on the top of the stack

Method Detail

getValueOnStack

public T getValueOnStack()

Yields the computed value of the last SymbolicExpression handled by this domain, either through Environment.assign(Identifier, SymbolicExpression, ProgramPoint) or smallStepSemantics(ValueExpression, ProgramPoint).

Returns:

the value computed for the last expression

mk

public ValueEnvironment<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<ValueEnvironment<T extends NonRelationalValueDomain<T>>,Identifier,T extends NonRelationalValueDomain<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

copy

public ValueEnvironment<T> copy()

Description copied from class: Environment

Copies this environment. The function of the returned environment must be a (shallow) copy of the one of the given environment.

Specified by:

copy in class Environment<ValueEnvironment<T extends NonRelationalValueDomain<T>>,ValueExpression,T extends NonRelationalValueDomain<T>,T extends NonRelationalValueDomain<T>>

Returns:

a copy of the given environment

eval

public org.apache.commons.lang3.tuple.Pair<T,T> eval(ValueExpression expression,
                                                           ProgramPoint pp)
                                                    throws SemanticException

Description copied from class: Environment

Yields the evaluation of the given expression, happening at the given program point. The result of the evaluation is in the form of <abstract element, evaluation result>, where evaluation result is the true result of the evaluation, while abstract element is the element derived by the result that is to be stored inside the environment mapped to an identifier.

Specified by:

eval in class Environment<ValueEnvironment<T extends NonRelationalValueDomain<T>>,ValueExpression,T extends NonRelationalValueDomain<T>,T extends NonRelationalValueDomain<T>>

Parameters:

expression - the expression to evaluate

pp - the program point where the evaluation happens

Returns:

the result of the evaluation

Throws:

SemanticException - if something goes wrong during the evaluation

assignAux

public ValueEnvironment<T> assignAux(Identifier id,
                                     ValueExpression expression,
                                     java.util.Map<Identifier,T> function,
                                     T value,
                                     T eval,
                                     ProgramPoint pp)

Description copied from class: Environment

Auxiliary function of Environment.assign(Identifier, SymbolicExpression, ProgramPoint) that is invoked after the evaluation of the expression.

Specified by:

assignAux in class Environment<ValueEnvironment<T extends NonRelationalValueDomain<T>>,ValueExpression,T extends NonRelationalValueDomain<T>,T extends NonRelationalValueDomain<T>>

Parameters:

id - the identifier that has been assigned

expression - the expression that has been evaluated and assigned

function - a copy of the current function, where the id has been assigned to eval

value - the final value stored for id, after considering applying NonRelationalElement.variable(Identifier, ProgramPoint) and Identifier.isWeak()

eval - the abstract value that is the result of the evaluation of value

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

Returns:

a new instance of this environment containing the given function, obtained by assigning id to eval

smallStepSemantics

public ValueEnvironment<T> smallStepSemantics(ValueExpression expression,
                                              ProgramPoint pp)
                                       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<ValueEnvironment<T extends NonRelationalValueDomain<T>>,ValueExpression,Identifier>

Parameters:

expression - the expression whose semantics need to be computed

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

Returns:

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

Throws:

SemanticException - if an error occurs during the computation

assumeSatisfied

public ValueEnvironment<T> assumeSatisfied(T eval)

Description copied from class: Environment

Assumes that an expression, that evaluated to eval, is always satisfied by this environment. This auxiliary method serves as a constructor for the final concrete instance of environment.

Specified by:

assumeSatisfied in class Environment<ValueEnvironment<T extends NonRelationalValueDomain<T>>,ValueExpression,T extends NonRelationalValueDomain<T>,T extends NonRelationalValueDomain<T>>

Parameters:

eval - the result of the evaluation of the expression that is always satisfied

Returns:

the (possibly) updated environment

glbAux

public ValueEnvironment<T> glbAux(T lattice,
                                  java.util.Map<Identifier,T> function,
                                  ValueEnvironment<T> other)
                           throws SemanticException

Description copied from class: Environment

Auxiliary glb operation, invoked after the result has been computed to create the concrete instance of environment. Note that any additional information that is instance-specific (i.e. anything but function and lattice singleton) has to be computed by this method.

Specified by:

glbAux in class Environment<ValueEnvironment<T extends NonRelationalValueDomain<T>>,ValueExpression,T extends NonRelationalValueDomain<T>,T extends NonRelationalValueDomain<T>>

Parameters:

lattice - the lattice that is the result of the glb

function - the function that is the result of the glb (might be null

other - the other environment

Returns:

the final instance of the glb

Throws:

SemanticException - if an error occurs during the computation

top

public ValueEnvironment<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 NonRelationalValueDomain<T>>

Returns:

the top element

bottom

public ValueEnvironment<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 NonRelationalValueDomain<T>>

Returns:

the bottom element

hashCode

public int hashCode()

Overrides:

hashCode in class FunctionalLattice<ValueEnvironment<T extends NonRelationalValueDomain<T>>,Identifier,T extends NonRelationalValueDomain<T>>

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class FunctionalLattice<ValueEnvironment<T extends NonRelationalValueDomain<T>>,Identifier,T extends NonRelationalValueDomain<T>>

representation

public DomainRepresentation representation()

Description copied from interface: SemanticDomain

Yields a DomainRepresentation of the information contained in this domain's instance.

Specified by:

representation in interface SemanticDomain<ValueEnvironment<T extends NonRelationalValueDomain<T>>,ValueExpression,Identifier>

Overrides:

representation in class Environment<ValueEnvironment<T extends NonRelationalValueDomain<T>>,ValueExpression,T extends NonRelationalValueDomain<T>,T extends NonRelationalValueDomain<T>>

Returns:

the representation