de.uka.ilkd.key.rule.join

Class JoinRule

java.lang.Object

de.uka.ilkd.key.rule.join.JoinRule

All Implemented Interfaces:

BuiltInRule, Rule

public class JoinRule
extends Object
implements BuiltInRule

Base for implementing join rules. Extend this class, implement method joinValuesInStates(...) and register in class JavaProfile.

The rule is applicable if the chosen subterm has the form { x := v || ... } PHI and there are potential join candidates.

Any rule application returned will be incomplete; completion is handled by de.uka.ilkd.key.gui.joinrule.JoinRuleCompletion.

Author:

Dominic Scheurer

See Also:

JoinRuleUtils, JoinWeaken, JoinIfThenElse, JoinIfThenElseAntecedent, JoinWithLatticeAbstraction, JoinWithSignLattice, JoinRuleCompletion, JoinPartnerSelectionDialog

Field Summary

Fields

Modifier and Type	Field and Description
private static String	DISPLAY_NAME
static JoinRule	INSTANCE
private static int	MAX_UPDATE_TERM_DEPTH_FOR_CHECKING Thresholds the maximum depth of right sides in updates for which an equivalence proof is started.
protected static boolean	RIGHT_SIDE_EQUIVALENCE_ONLY_SYNTACTICAL If set to true, join rules are expected to check the equivalence for right sides (for preserving idempotency) only on a pure syntactical basis.
private static Name	RULE_NAME
private static int	SIMPLIFICATION_TIMEOUT_MS Time threshold in milliseconds for the automatic simplification of formulae (side proofs are stopped after that amount of time).

Constructor Summary

Constructors

Constructor and Description
JoinRule() JoinRule is a Singleton class, therefore constructor only package-wide visible.

Method Summary

Modifier and Type	Method and Description
ImmutableList<Goal>	apply(Goal goal, Services services, RuleApp ruleApp) the rule is applied on the given goal using the information of rule application.
IBuiltInRuleApp	createApp(PosInOccurrence pio, TermServices services)
String	displayName() returns the display name of the rule
static ImmutableList<Triple<Goal,PosInOccurrence,HashMap<ProgramVariable,ProgramVariable>>>	findPotentialJoinPartners(Goal goal, PosInOccurrence pio) Finds all suitable join partners.
static ImmutableList<Triple<Goal,PosInOccurrence,HashMap<ProgramVariable,ProgramVariable>>>	findPotentialJoinPartners(Goal goal, PosInOccurrence pio, Node start) Finds all suitable join partners below the start node.
boolean	isApplicable(Goal goal, PosInOccurrence pio) We admit top level formulas of the form \<{ ...
boolean	isApplicableOnSubTerms()
static boolean	isOfAdmissibleForm(Goal goal, PosInOccurrence pio, boolean doJoinPartnerCheck) We admit top level formulas of the form \<{ ...
protected Triple<ImmutableSet<Term>,Term,ImmutableSet<Name>>	joinHeaps(JoinProcedure joinRule, LocationVariable heapVar, Term heap1, Term heap2, SymbolicExecutionState state1, SymbolicExecutionState state2, Term distinguishingFormula, Services services) Joins two heaps in a zip-like procedure.
protected Pair<SymbolicExecutionState,ImmutableSet<Name>>	joinStates(JoinProcedure joinRule, SymbolicExecutionState state1, SymbolicExecutionState state2, Term programCounter, Term distinguishingFormula, Services services) Joins two SE states (U1,C1,p) and (U2,C2,p) according to the method JoinRule#joinValuesInStates(LocationVariable, SymbolicExecutionState, Term, SymbolicExecutionState, Term, Services) .
Name	name() the name of the rule
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

INSTANCE

public static final JoinRule INSTANCE

DISPLAY_NAME

private static final String DISPLAY_NAME

See Also:

Constant Field Values

RULE_NAME

private static final Name RULE_NAME

RIGHT_SIDE_EQUIVALENCE_ONLY_SYNTACTICAL

protected static final boolean RIGHT_SIDE_EQUIVALENCE_ONLY_SYNTACTICAL

If set to true, join rules are expected to check the equivalence for right sides (for preserving idempotency) only on a pure syntactical basis. If set to false, they are allowed to do a proof to check the equivalence in the respective contexts.

See Also:

Constant Field Values

MAX_UPDATE_TERM_DEPTH_FOR_CHECKING

private static final int MAX_UPDATE_TERM_DEPTH_FOR_CHECKING

Thresholds the maximum depth of right sides in updates for which an equivalence proof is started. We skip the check for equal valuation of this variable if the depth threshold is exceeded by one of the right sides. Experiments show a very big time overhead from a depth of about 8-10 on, or sometimes even earlier.

See Also:

Constant Field Values

SIMPLIFICATION_TIMEOUT_MS

private static final int SIMPLIFICATION_TIMEOUT_MS

Time threshold in milliseconds for the automatic simplification of formulae (side proofs are stopped after that amount of time).

See Also:

Constant Field Values

Constructor Detail

JoinRule

JoinRule()

JoinRule is a Singleton class, therefore constructor only package-wide visible.

Method Detail

name

public Name name()

Description copied from interface: Rule

the name of the rule

Specified by:

name in interface Rule

displayName

public String displayName()

Description copied from interface: Rule

returns the display name of the rule

Specified by:

displayName in interface Rule

toString

public String toString()

Overrides:

toString in class Object

apply

public final ImmutableList<Goal> apply(Goal goal,
                                       Services services,
                                       RuleApp ruleApp)
                                throws RuleAbortException

Description copied from interface: Rule

the rule is applied on the given goal using the information of rule application.

Specified by:

apply in interface Rule

Parameters:

goal - the Goal on which to apply ruleApp

services - the Services with the necessary information about the java programs

ruleApp - the rule application to be executed

Returns:

all open goals below \old(goal.node()), i.e. the goals resulting from the rule application

Throws:

RuleAbortException

joinStates

protected Pair<SymbolicExecutionState,ImmutableSet<Name>> joinStates(JoinProcedure joinRule,
                                                                     SymbolicExecutionState state1,
                                                                     SymbolicExecutionState state2,
                                                                     Term programCounter,
                                                                     Term distinguishingFormula,
                                                                     Services services)

Joins two SE states (U1,C1,p) and (U2,C2,p) according to the method JoinRule#joinValuesInStates(LocationVariable, SymbolicExecutionState, Term, SymbolicExecutionState, Term, Services) . p must be the same in both states, so it is supplied separately.

Override this method for special join procedures.

Parameters:

joinRule - The join procedure to use for the join.

state1 - First state to join.

state2 - Second state to join.

programCounter - The formula \<{ ... }\> phi consisting of the common program counter and the post condition.

distinguishingFormula - The user-specified distinguishing formula. May be null (for automatic generation).

services - The services object.

Returns:

A new joined SE state (U*,C*) which is a weakening of the original states.

joinHeaps

protected Triple<ImmutableSet<Term>,Term,ImmutableSet<Name>> joinHeaps(JoinProcedure joinRule,
                                                                       LocationVariable heapVar,
                                                                       Term heap1,
                                                                       Term heap2,
                                                                       SymbolicExecutionState state1,
                                                                       SymbolicExecutionState state2,
                                                                       Term distinguishingFormula,
                                                                       Services services)

Joins two heaps in a zip-like procedure. The fallback is an if-then-else construct that is tried to be shifted as far inwards as possible.

Override this method for specialized heap join procedures.

Parameters:

heapVar - The heap variable for which the values should be joined.

heap1 - The first heap term.

heap2 - The second heap term.

state1 - SE state for the first heap term.

state2 - SE state for the second heap term

services - The services object.

distinguishingFormula - The user-specified distinguishing formula. May be null (for automatic generation).

Returns:

A joined heap term.

isApplicable

public boolean isApplicable(Goal goal,
                            PosInOccurrence pio)

We admit top level formulas of the form \<{ ... }\> phi and U \<{ ... }\> phi, where U must be an update in normal form, i.e. a parallel update of elementary updates.

Specified by:

isApplicable in interface BuiltInRule

Parameters:

goal - Current goal.

pio - Position of selected sequent formula.

Returns:

true iff a suitable top level formula for joining.

isOfAdmissibleForm

public static boolean isOfAdmissibleForm(Goal goal,
                                         PosInOccurrence pio,
                                         boolean doJoinPartnerCheck)

We admit top level formulas of the form \<{ ... }\> phi and U \<{ ... }\> phi, where U must be an update in normal form, i.e. a parallel update of elementary updates. We require that phi does not contain a Java block.

Parameters:

goal - Current goal.

pio - Position of selected sequent formula.

doJoinPartnerCheck - Checks for available join partners iff this flag is set to true.

Returns:

true iff a suitable top level formula for joining.

isApplicableOnSubTerms

public boolean isApplicableOnSubTerms()

Specified by:

isApplicableOnSubTerms in interface BuiltInRule

createApp

public IBuiltInRuleApp createApp(PosInOccurrence pio,
                                 TermServices services)

Specified by:

createApp in interface BuiltInRule

findPotentialJoinPartners

public static ImmutableList<Triple<Goal,PosInOccurrence,HashMap<ProgramVariable,ProgramVariable>>> findPotentialJoinPartners(Goal goal,
                                                                                                                             PosInOccurrence pio)

Finds all suitable join partners.

Parameters:

goal - Current goal to join.

pio - Position of update-program counter formula in goal.

services - The services object.

Returns:

A list of suitable join partners. May be empty if none exist.

findPotentialJoinPartners

public static ImmutableList<Triple<Goal,PosInOccurrence,HashMap<ProgramVariable,ProgramVariable>>> findPotentialJoinPartners(Goal goal,
                                                                                                                             PosInOccurrence pio,
                                                                                                                             Node start)

Finds all suitable join partners below the start node.

Parameters:

goal - Current goal to join.

pio - Position of update-program counter formula in goal.

start - Node to start the search with.

services - The services object.

Returns:

A list of suitable join partners. May be empty if none exist.