Package it.unive.lisa.program.cfg.fixpoints

Class BackwardDescendingNarrowingFixpoint<A extends AbstractState<A>>

java.lang.Object

it.unive.lisa.program.cfg.fixpoints.BackwardCFGFixpoint<A>

it.unive.lisa.program.cfg.fixpoints.BackwardDescendingNarrowingFixpoint<A>

Type Parameters:

A - the type of AbstractState contained into the analysis state

All Implemented Interfaces:

Fixpoint.FixpointImplementation<Statement,Edge,CFGFixpoint.CompoundState<A>>

public class BackwardDescendingNarrowingFixpoint<A extends AbstractState<A>>
extends BackwardCFGFixpoint<A>

A CFGFixpoint that traverses descending chains using narrowings.

Field Summary

Fields inherited from class it.unive.lisa.program.cfg.fixpoints.BackwardCFGFixpoint

graph, interprocedural

Constructor Summary

Constructors

Constructor	Description
BackwardDescendingNarrowingFixpoint(CFG target, InterproceduralAnalysis<A> interprocedural, FixpointConfiguration config)	Builds the fixpoint implementation.

Method Summary

Modifier and Type	Method	Description
boolean	equality(Statement node, CFGFixpoint.CompoundState<A> approx, CFGFixpoint.CompoundState<A> old)	Given a node and two states, yields whether or not the most recent one has to be considered equal to the older one in terms of fixpoint iterations.
CFGFixpoint.CompoundState<A>	operation(Statement node, CFGFixpoint.CompoundState<A> approx, CFGFixpoint.CompoundState<A> old)	Given a node and two states, joins the states (i.e.

Methods inherited from class it.unive.lisa.program.cfg.fixpoints.BackwardCFGFixpoint

semantics, traverse, union

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

BackwardDescendingNarrowingFixpoint

public BackwardDescendingNarrowingFixpoint(CFG target,
                                           InterproceduralAnalysis<A> interprocedural,
                                           FixpointConfiguration config)

Builds the fixpoint implementation.

Parameters:

target - the target of the implementation

interprocedural - the InterproceduralAnalysis to use for semantics computations

config - the FixpointConfiguration to use

Method Detail

operation

public CFGFixpoint.CompoundState<A> operation(Statement node,
                                              CFGFixpoint.CompoundState<A> approx,
                                              CFGFixpoint.CompoundState<A> old)
                                       throws SemanticException

Description copied from interface: Fixpoint.FixpointImplementation

Given a node and two states, joins the states (i.e. least upper bound or widening) together.

This callback is invoked after the exit state of a node has been computed through Fixpoint.FixpointImplementation.semantics(Object, Object), to join it with results from older fixpoint iterations.

Parameters:

node - the node where the computation takes place

approx - the most recent state

old - the older state

Returns:

the joined state

Throws:

SemanticException

equality

public boolean equality(Statement node,
                        CFGFixpoint.CompoundState<A> approx,
                        CFGFixpoint.CompoundState<A> old)
                 throws SemanticException

Description copied from interface: Fixpoint.FixpointImplementation

Given a node and two states, yields whether or not the most recent one has to be considered equal to the older one in terms of fixpoint iterations. This means that if this method returns true, than the result for the given node won't be updated and the successors of such node won't be added back to the list of nodes to process.

This callback is invoked after the exit state of a node has been computed through Fixpoint.FixpointImplementation.semantics(Object, Object) and joined with the older one through Fixpoint.FixpointImplementation.operation(Object, Object, Object).

Parameters:

node - the node where the computation takes place

approx - the most recent state

old - the older state

Returns:

true if there is no need to update the previous result, false otherwise

Throws:

SemanticException