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Handle initial value requirements in property behaviors.

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If a behavior protocol requires an `initialValue` static property, satisfy the requirement using the initial value expression from the property declaration. This lets us implement `lazy` as a property behavior.
This commit is contained in:
Joe Groff
2016-02-18 11:25:30 -08:00
parent 12b8a92e9d
commit c6bfac7281
8 changed files with 412 additions and 91 deletions
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111
lib/Sema/CodeSynthesis.cpp
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@@ -1220,6 +1220,14 @@ void TypeChecker::completePropertyBehaviorStorage(VarDecl *VD,
DC);
Storage->setInterfaceType(SubstStorageInterfaceTy);
Storage->setUserAccessible(false);
// Mark the vardecl to be final, implicit, and private. In a class, this
// prevents it from being dynamically dispatched.
if (VD->getDeclContext()->getAsClassOrClassExtensionContext())
makeFinal(Context, Storage);
Storage->setImplicit();
Storage->setAccessibility(Accessibility::Private);
Storage->setSetterAccessibility(Accessibility::Private);
addMemberToContextIfNeeded(Storage, DC);
// Build the initializer expression, 'Self.initStorage()', using the
@@ -1266,14 +1274,6 @@ void TypeChecker::completePropertyBehaviorStorage(VarDecl *VD,
PBD->setInitializerChecked(0);
addMemberToContextIfNeeded(PBD, VD->getDeclContext(), VD);
// Mark the vardecl to be final, implicit, and private. In a class, this
// prevents it from being dynamically dispatched.
if (VD->getDeclContext()->getAsClassOrClassExtensionContext())
makeFinal(Context, Storage);
Storage->setImplicit();
Storage->setAccessibility(Accessibility::Private);
Storage->setSetterAccessibility(Accessibility::Private);
// Add accessors to the storage, since we'll need them to satisfy the
// conformance requirements.
addTrivialAccessorsToStorage(Storage, *this);
@@ -1294,6 +1294,89 @@ void TypeChecker::completePropertyBehaviorStorage(VarDecl *VD,
ConcreteDeclRef(Context, Storage->getSetter(), MemberSubs));
}
void TypeChecker::completePropertyBehaviorInitialValue(VarDecl *VD,
VarDecl *BehaviorInitialValue,
NormalProtocolConformance *BehaviorConformance,
ArrayRef<Substitution> SelfInterfaceSubs,
ArrayRef<Substitution> SelfContextSubs) {
// Create a property to witness the requirement.
auto DC = VD->getDeclContext();
SmallString<64> NameBuf = VD->getName().str();
NameBuf += ".initialValue";
auto InitialValueName = Context.getIdentifier(NameBuf);
// TODO: non-static initialValue
assert(BehaviorInitialValue->isStatic());
auto *InitialValue = new (Context) VarDecl(/*static*/ true,
/*let*/ false,
VD->getLoc(),
InitialValueName,
SelfContextSubs[1].getReplacement(),
DC);
InitialValue->setInterfaceType(SelfInterfaceSubs[1].getReplacement());
InitialValue->setUserAccessible(false);
// Mark the vardecl to be final, implicit, and private. In a class, this
// prevents it from being dynamically dispatched.
if (VD->getDeclContext()->getAsClassOrClassExtensionContext())
makeFinal(Context, InitialValue);
InitialValue->setImplicit();
InitialValue->setAccessibility(Accessibility::Private);
InitialValue->setIsBeingTypeChecked();
addMemberToContextIfNeeded(InitialValue, DC);
Pattern *InitialPBDPattern = new (Context) NamedPattern(InitialValue,
/*implicit*/true);
InitialPBDPattern = new (Context) TypedPattern(InitialPBDPattern,
TypeLoc::withoutLoc(SelfContextSubs[1].getReplacement()),
/*implicit*/ true);
auto *InitialPBD = PatternBindingDecl::create(Context,
/*staticloc*/SourceLoc(),
StaticSpellingKind::KeywordStatic,
VD->getLoc(),
InitialPBDPattern, nullptr,
VD->getDeclContext());
InitialPBD->setImplicit();
InitialPBD->setInitializerChecked(0);
addMemberToContextIfNeeded(InitialPBD, VD->getDeclContext(), VD);
// Create a getter.
auto Get = createGetterPrototype(InitialValue, *this);
addMemberToContextIfNeeded(Get, DC);
// Take the initializer from the PatternBindingDecl for VD.
auto *InitValue = VD->getParentInitializer();
auto PBD = VD->getParentPatternBinding();
unsigned entryIndex = PBD->getPatternEntryIndexForVarDecl(VD);
PBD->setInit(entryIndex, nullptr);
PBD->setInitializerChecked(entryIndex);
// Recontextualize any closure declcontexts nested in the initializer to
// realize that they are in the getter function.
InitValue->walk(RecontextualizeClosures(Get));
// Return the expression value.
auto Ret = new (Context) ReturnStmt(SourceLoc(), InitValue,
/*implicit*/ true);
auto Body = BraceStmt::create(Context, SourceLoc(), ASTNode(Ret),
SourceLoc(), /*implicit*/ true);
Get->setBody(Body);
InitialValue->makeComputed(SourceLoc(), Get, nullptr, nullptr, SourceLoc());
InitialValue->setIsBeingTypeChecked(false);
// Add the witnesses to the conformance.
ArrayRef<Substitution> MemberSubs;
if (DC->isGenericTypeContext()) {
MemberSubs = DC->getGenericParamsOfContext()
->getForwardingSubstitutions(Context);
}
BehaviorConformance->setWitness(BehaviorInitialValue,
ConcreteDeclRef(Context, InitialValue, MemberSubs));
BehaviorConformance->setWitness(BehaviorInitialValue->getGetter(),
ConcreteDeclRef(Context, Get, MemberSubs));
}
void TypeChecker::completePropertyBehaviorAccessors(VarDecl *VD,
VarDecl *ValueImpl,
ArrayRef<Substitution> SelfInterfaceSubs,
@@ -1559,20 +1642,26 @@ void swift::maybeAddAccessorsToVariable(VarDecl *var, TypeChecker &TC) {
NormalProtocolConformance *conformance = nullptr;
VarDecl *valueProp = nullptr;
bool mightBeMutating = dc->isTypeContext()
&& !var->isStatic()
&& !dc->getDeclaredInterfaceType()->getClassOrBoundGenericClass();
auto makeBehaviorAccessors = [&]{
FuncDecl *getter;
FuncDecl *setter = nullptr;
if (valueProp && valueProp->getGetter()) {
getter = createGetterPrototype(var, TC);
// The getter is mutating if the behavior implementation is.
getter->setMutating(valueProp->getGetter()->isMutating());
// The getter is mutating if the behavior implementation is, unless
// we're in a class or non-instance context.
getter->setMutating(mightBeMutating &&
valueProp->getGetter()->isMutating());
getter->setAccessibility(var->getFormalAccess());
// Make a setter if the behavior property has one.
if (auto valueSetter = valueProp->getSetter()) {
ParamDecl *newValueParam = nullptr;
setter = createSetterPrototype(var, newValueParam, TC);
setter->setMutating(valueSetter->isMutating());
setter->setMutating(mightBeMutating && valueSetter->isMutating());
// TODO: max of property and implementation setter visibility?
setter->setAccessibility(var->getFormalAccess());
}