// we drop all arguments that are types. We also drop stars as
// arguments, for the benefit of Inj.
public Expr dropAnnos(Context ctxt) {
int iend = X.length;
Expr[] X2 = new Expr[iend];
boolean changed = false;
int cnt = 0;
for (int i = 0; i < iend; i++) {
Expr tmp = X[i];
if (tmp.isTypeOrKind(ctxt) || tmp.isProof(ctxt) || tmp.construct == STAR || specarg[i]) {
changed = true;
} else {
tmp = tmp.dropAnnos(ctxt);
X2[cnt] = tmp;
if (X2[cnt] != X[i]) {
changed = true;
}
cnt++;
}
}
Expr[] X3 = new Expr[cnt];
System.arraycopy(X2, 0, X3, 0, cnt);
Expr h = head.dropAnnos(ctxt);
if (X3.length == 0) {
return h;
}
if (changed || h != head) {
return new TermApp(h, X3);
}
return this;
}
/**
* Checks if the predicates are successful for the specified item.
*
* @param it item to be checked
* @param qc query context
* @return result of check
* @throws QueryException query exception
*/
protected final boolean preds(final Item it, final QueryContext qc) throws QueryException {
if (preds.length == 0) return true;
// set context value and position
final Value cv = qc.value;
try {
if (qc.scoring) {
double s = 0;
for (final Expr p : preds) {
qc.value = it;
final Item i = p.test(qc, info);
if (i == null) return false;
s += i.score();
}
it.score(Scoring.avg(s, preds.length));
} else {
for (final Expr p : preds) {
qc.value = it;
if (p.test(qc, info) == null) return false;
}
}
return true;
} finally {
qc.value = cv;
}
}
public Expr dropNoncompArgs(Context ctxt) {
if (ctxt.getFlag("debug_drop_noncomp")) {
ctxt.w.println("Dropping non-comp arguments from term-app " + toString(ctxt));
ctxt.w.flush();
}
ArrayList nX = new ArrayList();
ArrayList no = new ArrayList();
boolean changed = false;
Boolean b = new Boolean(false);
for (int i = 0, iend = X.length; i < iend; i++) {
if (X[i].isProof(ctxt) || specarg[i]) changed = true;
else {
nX.add(X[i]);
no.add(b);
}
}
Expr ret = this;
if (changed) {
if (nX.size() == 0) ret = head;
else ret = new TermApp(head, Parser.toExprArray(nX), Parser.toBooleanArray(no));
}
if (ctxt.getFlag("debug_drop_noncomp")) {
ctxt.w.println("Returning " + ret.toString(ctxt));
ctxt.w.flush();
}
return ret;
}
public Expr classify(Context ctxt, int approx, boolean spec) {
if (ctxt.getFlag("debug_classify_term_apps")) {
ctxt.w.print("(Classifying ");
print(ctxt.w, ctxt);
ctxt.w.println("");
ctxt.w.flush();
}
Expr cl = head.classify(ctxt, approx, spec).defExpandTop(ctxt, false, spec);
Expr ret = apply_classifier(FUN_TYPE, approx, spec, ctxt, cl, 0);
FunType ch = (FunType) ((FunType) cl).coalesce(ctxt, spec);
boolean check_spec_terminates = ctxt.getFlag("check_spec_terminates");
for (int i = 0; i < X.length; i++) {
if (ch.owned[i].status == Ownership.SPEC) {
if (check_spec_terminates) X[i].checkTermination(ctxt);
specarg[i] = true;
}
}
if (ctxt.getFlag("debug_classify_term_apps")) {
ctxt.w.println(") Classifier is:");
ret.print(ctxt.w, ctxt);
ctxt.w.println("");
ctxt.w.flush();
}
return ret;
}
@Override
public final Expr compile(final QueryContext qc, final VarScope scp) throws QueryException {
if (root != null) root = root.compile(qc, scp);
// no steps
if (steps.length == 0) return root == null ? new Context(info) : root;
final Value init = qc.value, cv = initial(qc);
final boolean doc = cv != null && cv.type == NodeType.DOC;
qc.value = cv;
try {
final int sl = steps.length;
for (int s = 0; s < sl; s++) {
Expr e = steps[s];
// axis step: if input is a document, its type is temporarily generalized
final boolean as = e instanceof Step;
if (as && s == 0 && doc) cv.type = NodeType.NOD;
e = e.compile(qc, scp);
if (e.isEmpty()) return optPre(qc);
steps[s] = e;
// no axis step: invalidate context value
if (!as) qc.value = null;
}
} finally {
if (doc) cv.type = NodeType.DOC;
qc.value = init;
}
// optimize path
return optimize(qc, scp);
}
@Override
public boolean has(final Flag flag) {
for (final Expr pred : preds) {
if (flag == Flag.FCS && pred.seqType().mayBeNumber() || pred.has(flag)) return true;
}
return false;
}
@Override
public final Expr optimize(final QueryContext qc, final VarScope scp) throws QueryException {
final Value v = initial(qc);
if (v != null && v.isEmpty() || emptyPath(v)) return optPre(qc);
// merge descendant steps
Expr e = mergeSteps(qc);
if (e == this && v != null && v.type == NodeType.DOC) {
// check index access
e = index(qc, v);
// rewrite descendant to child steps
if (e == this) e = children(qc, v);
}
// recompile path if it has changed
if (e != this) return e.compile(qc, scp);
// set atomic type for single attribute steps to speed up predicate tests
if (root == null && steps.length == 1 && steps[0] instanceof Step) {
final Step curr = (Step) steps[0];
if (curr.axis == ATTR && curr.test.kind == Kind.URI_NAME) curr.seqType(SeqType.NOD_ZO);
}
// choose best path implementation and set type information
final Path path = get(info, root, steps);
path.size = path.size(qc);
path.seqType = SeqType.get(steps[steps.length - 1].seqType().type, size);
return path;
}
@Override
public final boolean has(final Flag flag) {
// first step or root expression will be used as context
if (flag == Flag.CTX) return root == null || root.has(flag);
for (final Expr s : steps) if (s.has(flag)) return true;
return root != null && root.has(flag);
}
@Override
public boolean accept(final ASTVisitor visitor) {
if (!visitAll(visitor, specs)) return false;
for (final Expr ng : preExpr) if (!ng.accept(visitor)) return false;
for (final Var ng : post) if (!visitor.declared(ng)) return false;
return true;
}
@Override
public int exprSize() {
int sz = 0;
for (final Expr e : preExpr) sz += e.exprSize();
for (final Expr e : specs) sz += e.exprSize();
return sz;
}
public Eq(Expr e1, Expr e2) {
super(e1, e2, "==");
if (e1.getType().isPrimitive() != e2.getType().isPrimitive())
throw new IllegalArgumentException("type mismatch");
if (e1.getType().isPrimitive() && e1.getType() != e2.getType())
throw new IllegalArgumentException("type mismatch");
// FEATURE: Check if we can compare these classes
}
@Override
public void visit(ConstructMultiArrayInstruction insn) {
Expr[] dimensionExprs = new Expr[insn.getDimensions().size()];
for (int i = 0; i < dimensionExprs.length; ++i) {
dimensionExprs[i] = Expr.var(insn.getDimensions().get(i).getIndex());
}
assign(Expr.createArray(insn.getItemType(), dimensionExprs), insn.getReceiver());
}
@Override
public void visit(BinaryExpr expr) {
switch (expr.getOperation()) {
case AND:
case OR:
resultExpr = expr;
return;
default:
break;
}
expr.getSecondOperand().acceptVisitor(this);
Expr b = resultExpr;
if (b instanceof ConstantExpr && expr.getOperation() == BinaryOperation.SUBTRACT) {
if (tryMakePositive((ConstantExpr) b)) {
expr.setOperation(BinaryOperation.ADD);
}
}
expr.getFirstOperand().acceptVisitor(this);
Expr a = resultExpr;
Expr p = a;
Expr q = b;
boolean invert = false;
if (isZero(p)) {
Expr tmp = p;
p = q;
q = tmp;
invert = true;
}
if (isComparison(p) && isZero(q)) {
switch (expr.getOperation()) {
case EQUALS:
case NOT_EQUALS:
case LESS:
case LESS_OR_EQUALS:
case GREATER:
case GREATER_OR_EQUALS:
{
BinaryExpr comparison = (BinaryExpr) p;
Expr result =
BinaryExpr.binary(
expr.getOperation(),
comparison.getFirstOperand(),
comparison.getSecondOperand());
result.setLocation(comparison.getLocation());
if (invert) {
result = ExprOptimizer.invert(result);
}
resultExpr = result;
return;
}
default:
break;
}
}
expr.setFirstOperand(a);
expr.setSecondOperand(b);
resultExpr = expr;
}
@Override
public void visit(CloneArrayInstruction insn) {
MethodDescriptor cloneMethodDesc =
new MethodDescriptor("clone", ValueType.object("java.lang.Object"));
MethodReference cloneMethod = new MethodReference("java.lang.Object", cloneMethodDesc);
assign(
Expr.invoke(cloneMethod, Expr.var(insn.getArray().getIndex()), new Expr[0]),
insn.getReceiver());
}
@Override
public void visit(NewMultiArrayExpr expr) {
for (int i = 0; i < expr.getDimensions().size(); ++i) {
Expr dimension = expr.getDimensions().get(i);
dimension.acceptVisitor(this);
expr.getDimensions().set(i, resultExpr);
}
resultExpr = expr;
}
@Override
public void visit(AssignInstruction insn) {
AssignmentStatement stmt =
Statement.assign(
Expr.var(insn.getReceiver().getIndex()), Expr.var(insn.getAssignee().getIndex()));
stmt.getDebugNames().addAll(insn.getReceiver().getDebugNames());
stmt.setLocation(currentLocation);
statements.add(stmt);
}
@Override
public void visit(WhileStatement statement) {
if (statement.getBody().size() == 1 && statement.getBody().get(0) instanceof WhileStatement) {
WhileStatement innerLoop = (WhileStatement) statement.getBody().get(0);
BreakToContinueReplacer replacer = new BreakToContinueReplacer(innerLoop, statement);
replacer.visitSequence(innerLoop.getBody());
statement.getBody().clear();
statement.getBody().addAll(innerLoop.getBody());
}
List<Statement> statements = processSequence(statement.getBody());
for (int i = 0; i < statements.size(); ++i) {
if (statements.get(i) instanceof ContinueStatement) {
ContinueStatement continueStmt = (ContinueStatement) statements.get(i);
if (continueStmt.getTarget() == statement) {
statements.subList(i, statements.size()).clear();
break;
}
}
}
statement.getBody().clear();
statement.getBody().addAll(statements);
if (statement.getCondition() != null) {
List<Statement> sequenceBackup = resultSequence;
resultSequence = new ArrayList<>();
statement.getCondition().acceptVisitor(this);
statement.setCondition(resultExpr);
resultSequence = sequenceBackup;
}
while (true) {
if (!statement.getBody().isEmpty()
&& statement.getBody().get(0) instanceof ConditionalStatement) {
ConditionalStatement cond = (ConditionalStatement) statement.getBody().get(0);
if (cond.getConsequent().size() == 1
&& cond.getConsequent().get(0) instanceof BreakStatement) {
BreakStatement breakStmt = (BreakStatement) cond.getConsequent().get(0);
if (breakStmt.getTarget() == statement) {
statement.getBody().remove(0);
if (statement.getCondition() != null) {
Expr newCondition =
Expr.binary(
BinaryOperation.AND,
statement.getCondition(),
ExprOptimizer.invert(cond.getCondition()));
newCondition.setLocation(statement.getCondition().getLocation());
statement.setCondition(newCondition);
} else {
statement.setCondition(ExprOptimizer.invert(cond.getCondition()));
}
continue;
}
}
}
break;
}
resultStmt = statement;
}
@Override
public void visit(PutElementInstruction insn) {
AssignmentStatement stmt =
Statement.assign(
Expr.subscript(
Expr.var(insn.getArray().getIndex()), Expr.var(insn.getIndex().getIndex())),
Expr.var(insn.getValue().getIndex()));
stmt.setLocation(currentLocation);
statements.add(stmt);
}
/**
* Prepares this expression for iterative evaluation. The expression can be iteratively evaluated
* if no predicate or only the first is positional.
*
* @return result of check
*/
protected final boolean posIterator() {
// check if first predicate is numeric
if (preds.length == 1) {
Expr p = preds[0];
if (p instanceof Int) p = Pos.get(((Int) p).itr(), info);
pos = p instanceof Pos ? (Pos) p : null;
last = p.isFunction(Function.LAST);
preds[0] = p;
}
return pos != null || last;
}
@Override
public void visit(PutFieldInstruction insn) {
Expr right = Expr.var(insn.getValue().getIndex());
Expr left;
if (insn.getInstance() != null) {
left = Expr.qualify(Expr.var(insn.getInstance().getIndex()), insn.getField());
} else {
left = Expr.qualify(null, insn.getField());
}
AssignmentStatement stmt = Statement.assign(left, right);
stmt.setLocation(currentLocation);
statements.add(stmt);
}
// add selected vars
public void addQueryExpr(String s) {
try {
Expr expr = model.parseExpr(s);
if (expr instanceof RTVar) {
addQueryVar(expr);
} else {
Expr.List vars = new Expr.List();
expr.addNamedExpr(vars);
for (int i = 0; i < vars.size(); i++) addQueryVar(vars.expr(i));
}
} catch (Xcept e) {
// ignore
}
}
@Override
public Expr optimize(final QueryContext ctx, final VarScope scp) throws QueryException {
if (root instanceof Context) {
ctx.compInfo(OPTREMCTX);
root = null;
}
for (final Expr e : steps) {
// check for empty steps
if (e.isEmpty()) return optPre(null, ctx);
}
return this;
}
/** Type check the expression. */
public Node typeCheck(TypeChecker tc) throws SemanticException {
TypeSystem ts = tc.typeSystem();
if (!ts.isCastValid(expr.type(), castType.type())) {
throw new SemanticException(
"Cannot cast the expression of type \""
+ expr.type()
+ "\" to type \""
+ castType.type()
+ "\".",
position());
}
return type(castType.type());
}
/**
* Returns the initial context value of a path or {@code null}.
*
* @param qc query context (may be @code null)
* @return root
*/
private Value initial(final QueryContext qc) {
// current context value
final Value v = qc != null ? qc.value : null;
// no root or context expression: return context
if (root == null || root instanceof Context) return v;
// root reference
if (root instanceof Root) return v != null && v instanceof Item ? Root.root(v) : v;
// root is value: return root
if (root.isValue()) return (Value) root;
// data reference
final Data d = root.data();
if (d != null) return new DBNode(d, 0, Data.ELEM);
// otherwise, return null
return null;
}
public App spineForm(Context ctxt, boolean drop_annos, boolean spec, boolean expand_defs) {
Expr h = head;
Expr prev = null;
if (expand_defs) {
Expr prev2 = null;
while (h != prev) {
prev2 = prev;
prev = h;
h = h.defExpandOne(ctxt, drop_annos, spec);
}
if (prev2 != null) prev = prev2;
if (h.construct != construct && h.construct != CONST && h.construct != VAR)
/* we are trying to keep these constructs in the head. */
h = prev;
}
if (ctxt.getFlag("debug_spine_form")) {
ctxt.w.println("Computing spine form of " + toString(ctxt));
ctxt.w.println("{");
ctxt.w.println("Head expands to " + h.toString(ctxt));
ctxt.w.flush();
}
App ret = this;
if (h.construct == construct) {
TermApp e = (TermApp) ((TermApp) h).spineForm(ctxt, drop_annos, spec, expand_defs);
int eXlen = e.X.length;
int newlen = X.length + eXlen;
Expr[] X2 = new Expr[newlen];
boolean[] specarg2 = new boolean[newlen];
for (int i = 0; i < eXlen; i++) {
X2[i] = e.X[i];
specarg2[i] = e.specarg[i];
}
for (int i = 0, iend = X.length; i < iend; i++) {
X2[i + eXlen] = X[i];
specarg2[i + eXlen] = specarg[i];
}
ret = new TermApp(e.head, X2, specarg2);
} else if (h != head) ret = new TermApp(h, X, specarg);
if (ctxt.getFlag("debug_spine_form")) {
ret.print(ctxt.w, ctxt);
ctxt.w.println("\n}");
ctxt.w.flush();
}
return ret;
}
public List acceptCFG(CFGBuilder v, List succs) {
v.visitCFGList(inits, (cond != null ? cond.entry() : body.entry()));
if (cond != null) {
if (condIsConstantTrue()) {
v.visitCFG(cond, body.entry());
} else {
v.visitCFG(cond, FlowGraph.EDGE_KEY_TRUE, body.entry(), FlowGraph.EDGE_KEY_FALSE, this);
}
}
v.push(this).visitCFG(body, continueTarget());
v.visitCFGList(iters, (cond != null ? cond.entry() : body.entry()));
return succs;
}
public List throwTypes(TypeSystem ts) {
if (expr.type().isReference()) {
return Collections.singletonList(ts.ClassCastException());
}
return Collections.EMPTY_LIST;
}
/**
* Checks if the path can be rewritten for iterative evaluation.
*
* @param root root expression; can be a {@code null} reference
* @param steps path steps
* @return result of check
*/
private static boolean iterative(final Expr root, final Expr... steps) {
if (root == null || !root.iterable()) return false;
final int sl = steps.length;
for (int s = 0; s < sl; ++s) {
switch (((Step) steps[s]).axis) {
// reverse axes - don't iterate
case ANC:
case ANCORSELF:
case PREC:
case PRECSIBL:
return false;
// multiple, unsorted results - only iterate at last step,
// or if last step uses attribute axis
case DESC:
case DESCORSELF:
case FOLL:
case FOLLSIBL:
return s + 1 == sl || s + 2 == sl && ((Step) steps[s + 1]).axis == Axis.ATTR;
// allow iteration for CHILD, ATTR, PARENT and SELF axes
default:
}
}
return true;
}
public boolean subtermDefEqNoAnno(Context ctxt, Expr e) {
// This check is captured below, all arguments always evaluated for a terminating term
//
// If it's a TermApp of a constructor, we need to look at all the sub expressions
// if (head.construct == CONST && ctxt.isTermCtor((Const)head)) {
// for (int i = 0; i < X.length; i++)
// //if (X[i].defEqNoAnno(ctxt, e))
// if (X[i].subtermDefEqNoAnno(ctxt, e))
// return true;
// return false;
// } else {
// Same as the head?
// Same as the whole application? ("this")
if (head.subtermDefEqNoAnno(ctxt, e) || super.subtermDefEqNoAnno(ctxt, e)) return true;
// In our CBV instantiated function evaluation scheme, all arguments are evaluated, so check
// equality
for (int i = 0; i < X.length; i++) if (X[i].subtermDefEqNoAnno(ctxt, e)) return true;
// Same as any of the spline form TermApp "heads"?
for (int i = 0; i < X.length; i++) {
Expr[] newX = new Expr[i + 1];
for (int j = 0; j <= i; j++) {
newX[j] = X[j];
}
if (e.defEqNoAnno(ctxt, new TermApp(head, newX), true)) return true;
}
return false;
// }
}
/**
* Perform type propagation through a given expression, returning the type of value that is
* returned by evaluating this expression.
*
* @param e
* @param environment
* @param generics
* @param context
* @return
*/
private SemanticType propagate(
Expr e,
HashMap<String, SemanticType> environment,
HashSet<String> generics,
WyalFile.Context context) {
SemanticType t;
if (e instanceof Expr.Variable) {
t = propagate((Expr.Variable) e, environment, generics, context);
} else if (e instanceof Expr.Constant) {
t = propagate((Expr.Constant) e, environment, generics, context);
} else if (e instanceof Expr.Unary) {
t = propagate((Expr.Unary) e, environment, generics, context);
} else if (e instanceof Expr.Binary) {
t = propagate((Expr.Binary) e, environment, generics, context);
} else if (e instanceof Expr.Ternary) {
t = propagate((Expr.Ternary) e, environment, generics, context);
} else if (e instanceof Expr.Nary) {
t = propagate((Expr.Nary) e, environment, generics, context);
} else if (e instanceof Expr.Quantifier) {
t = propagate((Expr.Quantifier) e, environment, generics, context);
} else if (e instanceof Expr.FunCall) {
t = propagate((Expr.FunCall) e, environment, generics, context);
} else if (e instanceof Expr.IndexOf) {
t = propagate((Expr.IndexOf) e, environment, generics, context);
} else {
internalFailure("unknown expression encountered (" + e + ")", filename, e);
return null;
}
e.attributes().add(new TypeAttribute(t));
return returnType(e);
}
