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AST: Introduce ClassDecl::isSuperclassOf()

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This commit is contained in:
Slava Pestov
2019-03-20 15:30:48 -04:00
parent cece98b2ed
commit 1864f6f679
7 changed files with 37 additions and 57 deletions
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31
lib/SIL/DynamicCasts.cpp
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@@ -56,14 +56,14 @@ mustBridgeToSwiftValueBox(ModuleDecl *M, CanType T) {
return !M->getASTContext().getBridgedToObjC(M, T);
}
static bool canClassOrSuperclassesHaveExtensions(ClassDecl *CD,
bool isWholeModuleOpts) {
static bool canClassOrSuperclassesHaveUnknownSubclasses(ClassDecl *CD,
bool isWholeModuleOpts) {
while (CD) {
// Open classes can always be extended
// Open classes can always have unknown subclasses.
if (CD->getEffectiveAccess() == AccessLevel::Open)
return true;
// Internal and public classes can be extended, if we are not in
// Internal and public classes may have unknown subclasses if we are not in
// whole-module-optimization mode.
if (CD->getEffectiveAccess() >= AccessLevel::Internal &&
!isWholeModuleOpts)
@@ -110,11 +110,9 @@ classifyDynamicCastToProtocol(ModuleDecl *M, CanType source, CanType target,
}
// If it is a class and it can be proven that this class and its
// superclasses cannot be extended, then it is safe to proceed.
// No need to check this for structs, as they do not have any
// superclasses.
// superclasses cannot have unknown subclasses, then it is safe to proceed.
if (auto *CD = source.getClassOrBoundGenericClass()) {
if (canClassOrSuperclassesHaveExtensions(CD, isWholeModuleOpts))
if (canClassOrSuperclassesHaveUnknownSubclasses(CD, isWholeModuleOpts))
return DynamicCastFeasibility::MaySucceed;
// Derived types may conform to the protocol.
if (!CD->isFinal()) {
@@ -555,22 +553,13 @@ swift::classifyDynamicCast(ModuleDecl *M,
if (targetClass->usesObjCGenericsModel()) {
// If both classes are ObjC generics, the cast may succeed if the
// classes are related, irrespective of their generic parameters.
auto isDeclSuperclass = [&](ClassDecl *proposedSuper,
ClassDecl *proposedSub) -> bool {
do {
if (proposedSuper == proposedSub)
return true;
} while ((proposedSub = proposedSub->getSuperclassDecl()));
return false;
};
if (isDeclSuperclass(sourceClass, targetClass))
if (sourceClass->isSuperclassOf(targetClass))
return DynamicCastFeasibility::MaySucceed;
if (isDeclSuperclass(targetClass, sourceClass)) {
if (targetClass->isSuperclassOf(sourceClass))
return DynamicCastFeasibility::WillSucceed;
}
return DynamicCastFeasibility::WillFail;
}
}