std::string opt_type_info(const StringData *userType,
const TypeConstraint &tc) {
if (userType || tc.typeName() || tc.flags()) {
std::string utype = userType ? escaped(userType) : "N";
return folly::format("<{} {}> ",
utype,
type_constraint(tc)).str();
}
return "";
}
bool TypeConstraint::compat(const TypeConstraint& other) const {
if (other.isExtended() || isExtended()) {
/*
* Rely on the ahead of time typechecker---checking here can
* make it harder to convert a base class or interface to <?hh,
* because derived classes that are still <?php would all need
* to be modified.
*/
return true;
}
if (m_typeName == other.m_typeName) {
return true;
}
if (m_typeName && other.m_typeName) {
if (m_typeName->isame(other.m_typeName)) {
return true;
}
const Class* cls = Unit::lookupClass(m_typeName);
const Class* otherCls = Unit::lookupClass(other.m_typeName);
return cls && otherCls && cls == otherCls;
}
return false;
}
/*
* relaxConstraint returns the least specific TypeConstraint 'tc' that doesn't
* prevent the intersection of knownType and relaxType(toRelax, tc) from
* satisfying origTc. It is used in IRBuilder::constrainValue and
* IRBuilder::constrainStack to determine how to constrain the typeParam and
* src values of CheckType/CheckStk instructions, and the src values of
* AssertType/AssertStk instructions.
*
* AssertType example:
* t24:Obj<C> = AssertType<{Obj<C>|InitNull}> t4:Obj
*
* If constrainValue is called with (t24, DataTypeSpecialized), relaxConstraint
* will be called with (DataTypeSpecialized, Obj<C>|InitNull, Obj). After a few
* iterations it will determine that constraining Obj with DataTypeCountness
* will still allow the result type of the AssertType instruction to satisfy
* DataTypeSpecialized, because relaxType(Obj, DataTypeCountness) == Obj.
*/
TypeConstraint relaxConstraint(const TypeConstraint origTc,
const Type knownType, const Type toRelax) {
ITRACE(4, "relaxConstraint({}, knownType = {}, toRelax = {})\n",
origTc, knownType, toRelax);
Trace::Indent _i;
auto const dstType = refineType(knownType, toRelax);
always_assert_flog(typeFitsConstraint(dstType, origTc),
"refine({}, {}) doesn't fit {}",
knownType, toRelax, origTc);
// Preserve origTc's weak property.
TypeConstraint newTc{DataTypeGeneric, DataTypeGeneric};
newTc.weak = origTc.weak;
while (true) {
if (newTc.isSpecialized()) {
// We need to ask for the right kind of specialization, so grab it from
// origTc.
if (origTc.wantArrayKind()) newTc.setWantArrayKind();
if (origTc.wantClass()) newTc.setDesiredClass(origTc.desiredClass());
}
auto const relaxed = relaxType(toRelax, newTc);
auto const newDstType = refineType(relaxed, knownType);
if (typeFitsConstraint(newDstType, origTc)) break;
ITRACE(5, "newDstType = {}, newTc = {}; ", newDstType, newTc);
if (newTc.category == DataTypeGeneric ||
!typeFitsOuterConstraint(newDstType, origTc)) {
FTRACE(5, "incrementing outer\n");
incCategory(newTc.category);
} else if (!typeFitsInnerConstraint(newDstType, origTc)) {
FTRACE(5, "incrementing inner\n");
incCategory(newTc.innerCat);
} else {
not_reached();
}
}
ITRACE(4, "Returning {}\n", newTc);
// newTc shouldn't be any more specific than origTc.
always_assert(newTc.category <= origTc.category &&
newTc.innerCat <= origTc.innerCat);
return newTc;
}
bool typeFitsConstraint(Type t, TypeConstraint tc) {
switch (tc.category) {
case DataTypeGeneric:
return true;
case DataTypeCountness:
// Consumers using this constraint expect the type to be relaxed to
// Uncounted or left alone, so something like Arr|Obj isn't specific
// enough.
return !t.maybe(TCounted) ||
t.subtypeOfAny(TStr, TArr, TObj,
TRes, TBoxedCell);
case DataTypeCountnessInit:
return typeFitsConstraint(t, DataTypeCountness) &&
(t <= TUninit || !t.maybe(TUninit));
case DataTypeSpecific:
return t.isKnownDataType();
case DataTypeSpecialized:
// Type::isSpecialized() returns true for types like {Arr<Packed>|Int}
// and Arr has non-specialized subtypes, so we require that t is
// specialized, a strict subtype of Obj or Arr, and that it fits the
// specific requirements of tc.
assertx(tc.wantClass() ^ tc.wantArrayKind());
if (t < TObj && t.clsSpec()) {
return tc.wantClass() &&
t.clsSpec().cls()->classof(tc.desiredClass());
}
if (t < TArr && t.arrSpec()) {
auto arrSpec = t.arrSpec();
if (tc.wantArrayKind() && !arrSpec.kind()) return false;
return true;
}
return false;
}
not_reached();
}
bool typeFitsConstraint(Type t, TypeConstraint tc) {
always_assert(t != Type::Bottom);
switch (tc.category) {
case DataTypeGeneric:
return true;
case DataTypeCountness:
// Consumers using this constraint expect the type to be relaxed to
// Uncounted or left alone, so something like Arr|Obj isn't specific
// enough.
return t.notCounted() ||
t.subtypeOfAny(Type::Str, Type::Arr, Type::Obj,
Type::Res, Type::BoxedCell);
case DataTypeCountnessInit:
return typeFitsConstraint(t, DataTypeCountness) &&
(t <= Type::Uninit || t.not(Type::Uninit));
case DataTypeSpecific:
return t.isKnownDataType();
case DataTypeSpecialized:
// Type::isSpecialized() returns true for types like {Arr<Packed>|Int}
// and Arr has non-specialized subtypes, so we require that t is
// specialized, a strict subtype of Obj or Arr, and that it fits the
// specific requirements of tc.
assert(tc.wantClass() ^ tc.wantArrayKind());
if (!t.isSpecialized()) return false;
if (t < Type::Obj) {
return tc.wantClass() && t.getClass()->classof(tc.desiredClass());
}
if (t < Type::Arr) {
return tc.wantArrayKind() && t.hasArrayKind();
}
return false;
}
not_reached();
}
TypeConstraint applyConstraint(TypeConstraint tc, const TypeConstraint newTc) {
tc.category = std::max(newTc.category, tc.category);
if (newTc.wantArrayKind()) tc.setWantArrayKind();
if (newTc.wantClass()) {
if (tc.wantClass()) {
// It only makes sense to constrain tc with a class that's related to its
// existing class, and we want to preserve the more derived of the two.
auto cls1 = tc.desiredClass();
auto cls2 = newTc.desiredClass();
tc.setDesiredClass(cls1->classof(cls2) ? cls1 : cls2);
} else {
tc.setDesiredClass(newTc.desiredClass());
}
}
return tc;
}
/*
* Returns the least specific supertype of t that maintains the properties
* required by tc.
*/
Type relaxType(Type t, TypeConstraint tc) {
always_assert(t <= Type::Gen && t != Type::Bottom);
if (tc.category == DataTypeGeneric) return Type::Gen;
auto outerRelaxed = relaxOuter(t & Type::Cell, tc);
if (t.notBoxed()) return outerRelaxed;
auto innerType = (t & Type::BoxedCell).innerType();
auto innerRelaxed = tc.innerCat == DataTypeGeneric ? Type::Cell
: relaxOuter(innerType,
tc.inner());
// Only add outerRelax into the result type if t had a meaningful outer type
// coming in.
return (t.isBoxed() ? Type::Bottom : outerRelaxed) |
(innerRelaxed - Type::Uninit).box();
}
/*
* Returns true iff t is not boxed, or if tc.innerCat is satisfied by t's inner
* type.
*/
static bool typeFitsInnerConstraint(Type t, TypeConstraint tc) {
return tc.innerCat == DataTypeGeneric || t.notBoxed() ||
typeFitsOuterConstraint((t & Type::BoxedCell).innerType(), tc.inner());
}
std::string type_constraint(const TypeConstraint &tc) {
std::string typeName = tc.typeName() ? escaped(tc.typeName()) : "N";
return folly::format("{} {} ",
typeName,
type_flags_to_string(tc.flags())).str();
}
