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simplification tweaks 

git-svn-id: https://wala.svn.sourceforge.net/svnroot/wala/trunk@2703 f5eafffb-2e1d-0410-98e4-8ec43c5233c4
This commit is contained in:
sjfink 2008-03-13 19:04:50 +00:00
parent 0d61fe515d
commit e1adf2113b
2 changed files with 97 additions and 31 deletions
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2
com.ibm.wala.core/src/com/ibm/wala/logic/RelationFormula.java
View File

@ -93,7 +93,7 @@ public class RelationFormula implements IMaxTerm {
return new RelationFormula(R, l);
}
public static IFormula make(IRelation relation, List<ITerm> terms) {
public static RelationFormula make(IRelation relation, List<ITerm> terms) {
return new RelationFormula(relation, terms);
}

126
com.ibm.wala.core/src/com/ibm/wala/logic/Simplifier.java
View File

@ -87,7 +87,7 @@ public class Simplifier {
*
* This is inefficient.
*/
public static Collection<IFormula> simplify(Collection<IFormula> s, Collection<? extends IFormula> theory,
public static Collection<IFormula> simplify(Collection<? extends IFormula> s, Collection<? extends IFormula> theory,
ISemiDecisionProcedure dec) {
// the following is ad hoc and bogus.
// boolean changed = true;
@ -118,7 +118,7 @@ public class Simplifier {
/**
* Simplify the set s based on simple propositional logic.
*/
public static Collection<IFormula> propositionalSimplify(Collection<IFormula> s, Collection<? extends IFormula> t,
public static Collection<IFormula> propositionalSimplify(Collection<? extends IFormula> s, Collection<? extends IFormula> t,
ISemiDecisionProcedure dec) {
debug1(s, t);
Collection<ICNFFormula> cs = toCNF(s);
@ -239,7 +239,7 @@ public class Simplifier {
}
}
private static void debug1(Collection<IFormula> s, Collection<? extends IFormula> t) {
private static void debug1(Collection<? extends IFormula> s, Collection<? extends IFormula> t) {
if (DEBUG) {
System.err.println("--s--");
for (IFormula f : s) {
@ -389,41 +389,39 @@ public class Simplifier {
*
* @throws IllegalArgumentException if formula is null
*/
public static IFormula substitute(IFormula formula, ITerm t1, ITerm t2) {
public static IFormula substituteCNF(ICNFFormula formula, ITerm t1, ITerm t2) {
Collection<IMaxTerm> maxTerms = new ArrayList<IMaxTerm>();
for (IMaxTerm t : formula.getMaxTerms()) {
maxTerms.add(substituteMaxTerm(t, t1, t2));
}
return CNFFormula.make(maxTerms);
}
/**
* in formula f, substitute the term t2 for all free occurrences of t1
*
* @throws IllegalArgumentException if formula is null
*/
public static IMaxTerm substituteMaxTerm(IMaxTerm formula, ITerm t1, ITerm t2) {
if (formula == null) {
throw new IllegalArgumentException("formula is null");
}
switch (formula.getKind()) {
case BINARY:
AbstractBinaryFormula b = (AbstractBinaryFormula) formula;
// TODO separate out cases for CNFFormula and Disjunction?
IFormula F1 = b.getF1();
IFormula subF1 = substitute(F1, t1, t2);
IFormula F2 = b.getF2();
IFormula subF2 = substitute(F2, t1, t2);
if (F1 != subF1 || F2 != subF2) {
return BinaryFormula.make(b.getConnective(), subF1, subF2);
} else {
return formula;
Disjunction d = (Disjunction)formula;
Collection<IFormula> c = HashSetFactory.make();
for (IFormula clause : d.getClauses()) {
c.add(substitute(clause, t1, t2));
}
return Disjunction.make(c);
case NEGATION:
NotFormula n = (NotFormula) formula;
IFormula F = n.getFormula();
IFormula subF = substitute(F, t1, t2);
return F != subF ? NotFormula.make(subF) : formula;
NotFormulaMaxTerm n = (NotFormulaMaxTerm) formula;
RelationFormula F = (RelationFormula) n.getFormula();
RelationFormula subF = (RelationFormula)substitute(F, t1, t2);
return (F != subF ? NotFormulaMaxTerm.make(subF) : formula);
case QUANTIFIED:
QuantifiedFormula q = (QuantifiedFormula) formula;
if (q.getBoundVar().equals(t1)) {
return q;
} else {
IFormula body = q.getFormula();
IFormula subBody = substitute(body, t1, t2);
if (body != subBody) {
return QuantifiedFormula.make(q.getQuantifier(), q.getBoundVar(), subBody);
} else {
return formula;
}
}
Assertions.UNREACHABLE();
return null;
case RELATION:
RelationFormula r = (RelationFormula) formula;
List<ITerm> rTerms = r.getTerms();
@ -448,6 +446,74 @@ public class Simplifier {
}
}
/**
* in formula f, substitute the term t2 for all free occurrences of t1
*
* @throws IllegalArgumentException if formula is null
*/
public static IFormula substitute(IFormula formula, ITerm t1, ITerm t2) {
if (formula == null) {
throw new IllegalArgumentException("formula is null");
}
if (formula instanceof ICNFFormula) {
return substituteCNF((ICNFFormula) formula, t1, t2);
} else {
switch (formula.getKind()) {
case BINARY:
AbstractBinaryFormula b = (AbstractBinaryFormula) formula;
// TODO separate out cases for CNFFormula and Disjunction?
IFormula F1 = b.getF1();
IFormula subF1 = substitute(F1, t1, t2);
IFormula F2 = b.getF2();
IFormula subF2 = substitute(F2, t1, t2);
if (F1 != subF1 || F2 != subF2) {
return BinaryFormula.make(b.getConnective(), subF1, subF2);
} else {
return formula;
}
case NEGATION:
NotFormula n = (NotFormula) formula;
IFormula F = n.getFormula();
IFormula subF = substitute(F, t1, t2);
return F != subF ? NotFormula.make(subF) : formula;
case QUANTIFIED:
QuantifiedFormula q = (QuantifiedFormula) formula;
if (q.getBoundVar().equals(t1)) {
return q;
} else {
IFormula body = q.getFormula();
IFormula subBody = substitute(body, t1, t2);
if (body != subBody) {
return QuantifiedFormula.make(q.getQuantifier(), q.getBoundVar(), subBody);
} else {
return formula;
}
}
case RELATION:
RelationFormula r = (RelationFormula) formula;
List<ITerm> rTerms = r.getTerms();
List<ITerm> terms = new ArrayList<ITerm>(rTerms.size());
boolean someChange = false;
for (ITerm t : rTerms) {
Map<Wildcard, ITerm> binding = HashMapFactory.make();
ITerm subTerm = substituteInTerm(t, t1, t2, binding);
terms.add(subTerm);
someChange = someChange || t != subTerm;
}
if (someChange) {
return RelationFormula.make(r.getRelation(), terms);
} else {
return formula;
}
case CONSTANT:
return formula;
default:
Assertions.UNREACHABLE();
return null;
}
}
}
/**
* in term t, substitute t2 for free occurrences of t1
*/