improve model evaluation for Strings with Unicode characters.

Author: kfriedberger

src/org/sosy_lab/java_smt/solvers/cvc4/CVC4FormulaCreator.java

@@ -10,6 +10,7 @@
 
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkState;
+import static org.sosy_lab.java_smt.basicimpl.AbstractStringFormulaManager.unescapeUnicodeForSmtlib;
 
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableList;
@@ -611,7 +612,7 @@ public Object convertValue(Expr expForType, Expr value) {
       return convertFloatingPoint(value);
 
     } else if (valueType.isString()) {
-      return value.getConstString().toString();
+      return unescapeUnicodeForSmtlib(value.getConstString().toString());
 
     } else {
       // String serialization for unknown terms.

src/org/sosy_lab/java_smt/solvers/princess/PrincessStringFormulaManager.java

@@ -34,7 +34,8 @@ public class PrincessStringFormulaManager
   protected IExpression makeStringImpl(String value) {
     value = unescapeUnicodeForSmtlib(value);
     checkArgument(!containsSurrogatePair(value), "Princess does not support surrogate pairs.");
-    return PrincessEnvironment.stringTheory.string2Term(value);
+    IExpression strExpr = PrincessEnvironment.stringTheory.string2Term(value);
+    return getFormulaCreator().getEnv().simplify(strExpr); // simplify MOD in chars
   }
 
   /** returns whether any character of the string is part of a surrogate pair. */

src/org/sosy_lab/java_smt/solvers/z3/Z3FormulaCreator.java

@@ -9,6 +9,7 @@
 package org.sosy_lab.java_smt.solvers.z3;
 
 import static com.google.common.base.Preconditions.checkArgument;
+import static org.sosy_lab.java_smt.basicimpl.AbstractStringFormulaManager.unescapeUnicodeForSmtlib;
 
 import com.google.common.base.Preconditions;
 import com.google.common.collect.HashBasedTable;
@@ -893,7 +894,7 @@ public Object convertValue(Long value) {
         Rational ratValue = Rational.ofString(Native.getNumeralString(environment, value));
         return ratValue.isIntegral() ? ratValue.getNum() : ratValue;
       } else if (type.isStringType()) {
-        return Native.getString(environment, value);
+        return unescapeUnicodeForSmtlib(Native.getString(environment, value));
       } else if (type.isBitvectorType()) {
         return new BigInteger(Native.getNumeralString(environment, value));
       } else if (type.isFloatingPointType()) {

src/org/sosy_lab/java_smt/test/ModelEvaluationTest.java

@@ -147,9 +147,42 @@ public void testGetBooleansEvaluation() throws SolverException, InterruptedExcep
         Lists.newArrayList(null, bmgr.makeBoolean(defaultValue)));
   }
 
+  @SuppressWarnings("UnicodeEscape")
   @Test
   public void testGetStringsEvaluation() throws SolverException, InterruptedException {
     requireStrings();
+
+    // empty string
+    evaluateInModel(
+        smgr.equal(smgr.makeVariable("x"), smgr.makeString("")),
+        smgr.makeVariable("x"),
+        Lists.newArrayList(""),
+        Lists.newArrayList(smgr.makeString("")));
+
+    // normal string
+    evaluateInModel(
+        smgr.equal(smgr.makeVariable("x"), smgr.makeString("hello WORLD")),
+        smgr.makeVariable("x"),
+        Lists.newArrayList("hello WORLD"),
+        Lists.newArrayList(smgr.makeString("hello WORLD")));
+
+    // Unicode
+    evaluateInModel(
+        smgr.equal(smgr.makeVariable("x"), smgr.makeString("hello æ@€ \u1234 \\u{4321}")),
+        smgr.makeVariable("x"),
+        Lists.newArrayList("hello \u00e6@\u20ac \u1234 \u4321"),
+        Lists.newArrayList(smgr.makeString("hello \u00e6@\u20ac \u1234 \u4321")));
+
+    // TODO Z3 and CVC4 seem to break escaping on invalid Unicode Strings.
+    /*
+      evaluateInModel(
+        smgr.equal(smgr.makeVariable("x"), smgr.makeString("\\u")),
+        smgr.makeVariable("x"),
+        Lists.newArrayList("\\u"),
+        Lists.newArrayList(smgr.makeString("\\u")));
+    */
+
+    // foreign variable: x vs y
     evaluateInModel(
         smgr.equal(smgr.makeVariable("x"), smgr.makeString("hello")),
         smgr.makeVariable("y"),

src/org/sosy_lab/java_smt/test/SolverVisitorTest.java

@@ -745,7 +745,7 @@ public void stringInStringFormulaVisit() throws SolverException, InterruptedExce
             .add(smgr.charAt(x, offset))
             .add(smgr.toStringFormula(offset))
             .add(smgr.concat(x, y, z));
-    if (solverToUse() != Solvers.PRINCESS) {
+    if (solverToUse() != Solvers.PRINCESS) { // TODO Princess crashes with MatchError of IFunApp
       formulas.add(smgr.fromCodePoint(cp));
     }
     if (solverToUse() != Solvers.Z3) {
@@ -758,6 +758,14 @@ public void stringInStringFormulaVisit() throws SolverException, InterruptedExce
       assertThat(f2).isEqualTo(f);
       assertThatFormula(bmgr.not(smgr.equal(f, f2))).isUnsatisfiable();
     }
+    {
+      IntegerFormula f = smgr.toCodePoint(y);
+      mgr.visit(f, new FunctionDeclarationVisitorNoUF());
+      mgr.visit(f, new FunctionDeclarationVisitorNoOther(mgr));
+      IntegerFormula f2 = mgr.transformRecursively(f, new FormulaTransformationVisitor(mgr) {});
+      assertThat(f2).isEqualTo(f);
+      assertThatFormula(bmgr.not(imgr.equal(f, f2))).isUnsatisfiable();
+    }
   }
 
   @Test