Merge pull request #13742 from slavapestov/method-dispatch-cleanup

Method dispatch cleanup

Author: slavapestov

include/swift/AST/Decl.h

@@ -4248,14 +4248,6 @@ class AbstractStorageDecl : public ValueDecl {
   /// only valid on a declaration with Observing storage.
   FuncDecl *getDidSetFunc() const { return getDidSetInfo().DidSet; }
 
-  /// Return true if this storage can (but doesn't have to) be accessed with
-  /// Objective-C-compatible getters and setters.
-  bool hasForeignGetterAndSetter() const;
-
-  /// Return true if this storage *must* be accessed with Objective-C-compatible
-  /// getters and setters.
-  bool requiresForeignGetterAndSetter() const;
-
   /// Given that this is an Objective-C property or subscript declaration,
   /// produce its getter selector.
   ObjCSelector getObjCGetterSelector(LazyResolver *resolver = nullptr,

lib/AST/Decl.cpp

@@ -1260,34 +1260,25 @@ SourceRange IfConfigDecl::getSourceRange() const {
 }
 
 static bool isPolymorphic(const AbstractStorageDecl *storage) {
-  auto nominal = storage->getDeclContext()
-      ->getAsNominalTypeOrNominalTypeExtensionContext();
-  if (!nominal) return false;
-
-  switch (nominal->getKind()) {
-#define DECL(ID, BASE) case DeclKind::ID:
-#define NOMINAL_TYPE_DECL(ID, BASE)
-#include "swift/AST/DeclNodes.def"
-    llvm_unreachable("not a nominal type!");
-
-  case DeclKind::Struct:
-  case DeclKind::Enum:
-    return false;
+  if (storage->isDynamic())
+    return true;
 
-  case DeclKind::Protocol:
-    return !storage->getDeclContext()->isExtensionContext();
+  // Imported declarations behave like they are dynamic, even if they're
+  // not marked as such explicitly.
+  if (storage->isObjC() && storage->hasClangNode())
+    return true;
 
-  case DeclKind::Class:
-    // Final properties can always be direct, even in classes.
-    if (storage->isFinal())
-      return false;
-    // Extension properties are statically dispatched, unless they're @objc.
-    if (storage->getDeclContext()->isExtensionContext()
-        && !storage->isObjC())
+  if (auto *classDecl = dyn_cast<ClassDecl>(storage->getDeclContext())) {
+    if (storage->isFinal() || classDecl->isFinal())
       return false;
+
     return true;
   }
-  llvm_unreachable("bad DeclKind");
+
+  if (auto *protoDecl = dyn_cast<ProtocolDecl>(storage->getDeclContext()))
+    return true;
+
+  return false;
 }
 
 /// Determines the access semantics to use in a DeclRefExpr or
@@ -4186,36 +4177,6 @@ bool VarDecl::isSelfParameter() const {
   return false;
 }
 
-/// Return true if this stored property has a getter and
-/// setter that are accessible from Objective-C.
-bool AbstractStorageDecl::hasForeignGetterAndSetter() const {
-  if (auto override = getOverriddenDecl())
-    return override->hasForeignGetterAndSetter();
-
-  if (!isObjC())
-    return false;
-
-  return true;
-}
-
-bool AbstractStorageDecl::requiresForeignGetterAndSetter() const {
-  if (isFinal())
-    return false;
-  if (hasAccessorFunctions() && getGetter()->isImportAsMember())
-    return true;
-  if (!hasForeignGetterAndSetter())
-    return false;
-  // Imported accessors are foreign and only have objc entry points.
-  if (hasClangNode())
-    return true;
-  // Otherwise, we only dispatch by @objc if the declaration is dynamic,
-  // NSManaged, or dispatched through an ObjC protocol.
-  return isDynamic()
-    || getAttrs().hasAttribute<NSManagedAttr>()
-    || (isa<ProtocolDecl>(getDeclContext()) && isProtocolRequirement());
-}
-
-
 bool VarDecl::isAnonClosureParam() const {
   auto name = getName();
   if (name.empty())

lib/SIL/SILDeclRef.cpp

@@ -30,9 +30,6 @@ using namespace swift;
 /// Get the method dispatch mechanism for a method.
 MethodDispatch
 swift::getMethodDispatch(AbstractFunctionDecl *method) {
-  // Final methods can be statically referenced.
-  if (method->isFinal())
-    return MethodDispatch::Static;
   // Some methods are forced to be statically dispatched.
   if (method->hasForcedStaticDispatch())
     return MethodDispatch::Static;
@@ -41,23 +38,23 @@ swift::getMethodDispatch(AbstractFunctionDecl *method) {
   if (method->isImportAsMember())
     return MethodDispatch::Static;
 
-  // If this declaration is in a class but not marked final, then it is
-  // always dynamically dispatched.
   auto dc = method->getDeclContext();
-  if (isa<ClassDecl>(dc))
-    return MethodDispatch::Class;
 
-  // Class extension methods are only dynamically dispatched if they're
-  // dispatched by objc_msgSend, which happens if they're foreign or dynamic.
   if (dc->getAsClassOrClassExtensionContext()) {
-    if (method->hasClangNode())
-      return MethodDispatch::Class;
-    if (auto fd = dyn_cast<FuncDecl>(method)) {
-      if (fd->isAccessor() && fd->getAccessorStorageDecl()->hasClangNode())
-        return MethodDispatch::Class;
-    }
     if (method->isDynamic())
       return MethodDispatch::Class;
+
+    // Final methods can be statically referenced.
+    if (method->isFinal())
+      return MethodDispatch::Static;
+
+    // Members defined directly inside a class are dynamically dispatched.
+    if (isa<ClassDecl>(dc))
+      return MethodDispatch::Class;
+
+    // Imported class methods are dynamically dispatched.
+    if (method->isObjC() && method->hasClangNode())
+      return MethodDispatch::Class;
   }
 
   // Otherwise, it can be referenced statically.
@@ -79,151 +76,30 @@ bool swift::requiresForeignToNativeThunk(ValueDecl *vd) {
   return false;
 }
 
-/// FIXME: merge requiresForeignEntryPoint() into getMethodDispatch() and add
-/// an ObjectiveC case to the MethodDispatch enum.
 bool swift::requiresForeignEntryPoint(ValueDecl *vd) {
-  if (vd->isImportAsMember())
+  assert(!isa<AbstractStorageDecl>(vd));
+
+  if (vd->isDynamic())
     return true;
 
-  // Final functions never require ObjC dispatch.
-  if (vd->isFinal())
-    return false;
+  if (vd->isObjC() && isa<ProtocolDecl>(vd->getDeclContext()))
+    return true;
+
+  if (vd->isImportAsMember())
+    return true;
 
-  if (requiresForeignToNativeThunk(vd))
+  if (vd->hasClangNode())
     return true;
 
   if (auto *fd = dyn_cast<FuncDecl>(vd)) {
-  
     // Property accessors should be generated alongside the property.
-    if (fd->isGetterOrSetter())
-      return requiresForeignEntryPoint(fd->getAccessorStorageDecl());
-
-    return fd->isDynamic();
-  }
-
-  if (auto *cd = dyn_cast<ConstructorDecl>(vd)) {
-    if (cd->hasClangNode())
-      return true;
-
-    return cd->isDynamic();
-  }
-
-  if (auto *asd = dyn_cast<AbstractStorageDecl>(vd))
-    return asd->requiresForeignGetterAndSetter();
-
-  return vd->isDynamic();
-}
-
-/// TODO: We should consult the cached LoweredLocalCaptures the SIL
-/// TypeConverter calculates, but that would require plumbing SILModule&
-/// through every SILDeclRef constructor. Since this is only used to determine
-/// "natural uncurry level", and "uncurry level" is a concept we'd like to
-/// phase out, it's not worth it.
-static bool hasLoweredLocalCaptures(AnyFunctionRef AFR,
-                                    llvm::DenseSet<AnyFunctionRef> &visited) {
-  if (!AFR.getCaptureInfo().hasLocalCaptures())
-    return false;
-  
-  // Scan for local, non-function captures.
-  bool functionCapturesToRecursivelyCheck = false;
-  auto addFunctionCapture = [&](AnyFunctionRef capture) {
-    if (visited.find(capture) == visited.end())
-      functionCapturesToRecursivelyCheck = true;
-  };
-  for (auto &capture : AFR.getCaptureInfo().getCaptures()) {
-    if (!capture.getDecl()->getDeclContext()->isLocalContext())
-      continue;
-    // We transitively capture a local function's captures.
-    if (auto func = dyn_cast<AbstractFunctionDecl>(capture.getDecl())) {
-      addFunctionCapture(func);
-      continue;
-    }
-    // We may either directly capture properties, or capture through their
-    // accessors.
-    if (auto var = dyn_cast<VarDecl>(capture.getDecl())) {
-      switch (var->getStorageKind()) {
-      case VarDecl::StoredWithTrivialAccessors:
-        llvm_unreachable("stored local variable with trivial accessors?");
-
-      case VarDecl::InheritedWithObservers:
-        llvm_unreachable("inherited local variable?");
-
-      case VarDecl::StoredWithObservers:
-      case VarDecl::Addressed:
-      case VarDecl::AddressedWithTrivialAccessors:
-      case VarDecl::AddressedWithObservers:
-      case VarDecl::ComputedWithMutableAddress:
-        // Directly capture storage if we're supposed to.
-        if (capture.isDirect())
-          return true;
-
-        // Otherwise, transitively capture the accessors.
-        LLVM_FALLTHROUGH;
-
-      case VarDecl::Computed:
-        addFunctionCapture(var->getGetter());
-        if (auto setter = var->getSetter())
-          addFunctionCapture(setter);
-        continue;
-      
-      case VarDecl::Stored:
+    if (fd->isGetterOrSetter()) {
+      auto *asd = fd->getAccessorStorageDecl();
+      if (asd->isObjC() && asd->hasClangNode())
         return true;
-      }
     }
-    // Anything else is directly captured.
-    return true;
   }
-  
-  // Recursively consider function captures, since we didn't have any direct
-  // captures.
-  auto captureHasLocalCaptures = [&](AnyFunctionRef capture) -> bool {
-    if (visited.insert(capture).second)
-      return hasLoweredLocalCaptures(capture, visited);
-    return false;
-  };
-  
-  if (functionCapturesToRecursivelyCheck) {
-    for (auto &capture : AFR.getCaptureInfo().getCaptures()) {
-      if (!capture.getDecl()->getDeclContext()->isLocalContext())
-        continue;
-      if (auto func = dyn_cast<AbstractFunctionDecl>(capture.getDecl())) {
-        if (captureHasLocalCaptures(func))
-          return true;
-        continue;
-      }
-      if (auto var = dyn_cast<VarDecl>(capture.getDecl())) {
-        switch (var->getStorageKind()) {
-        case VarDecl::StoredWithTrivialAccessors:
-          llvm_unreachable("stored local variable with trivial accessors?");
-          
-        case VarDecl::InheritedWithObservers:
-          llvm_unreachable("inherited local variable?");
-          
-        case VarDecl::StoredWithObservers:
-        case VarDecl::Addressed:
-        case VarDecl::AddressedWithTrivialAccessors:
-        case VarDecl::AddressedWithObservers:
-        case VarDecl::ComputedWithMutableAddress:
-          assert(!capture.isDirect() && "should have short circuited out");
-          // Otherwise, transitively capture the accessors.
-          LLVM_FALLTHROUGH;
-          
-        case VarDecl::Computed:
-          if (captureHasLocalCaptures(var->getGetter()))
-            return true;
-          if (auto setter = var->getSetter())
-            if (captureHasLocalCaptures(setter))
-              return true;
-          continue;
-        
-        case VarDecl::Stored:
-          llvm_unreachable("should have short circuited out");
-        }
-      }
-      llvm_unreachable("should have short circuited out");
-    }
-  }
-  
+
   return false;
 }
 

lib/SILGen/SILGenApply.cpp

@@ -4736,7 +4736,7 @@ static Callee getBaseAccessorFunctionRef(SILGenFunction &SGF,
   }
 
   // Dispatch in a struct/enum or to a final method is always direct.
-  if (!isClassDispatch || decl->isFinal())
+  if (!isClassDispatch)
     return Callee::forDirect(SGF, constant, subs, loc);
 
   // Otherwise, if we have a non-final class dispatch to a normal method,
@@ -4974,28 +4974,10 @@ ArgumentSource SILGenFunction::prepareAccessorBaseArg(SILLocation loc,
   return Preparer.prepare();
 }
 
-static bool shouldReferenceForeignAccessor(AbstractStorageDecl *storage,
-                                           bool isDirectUse) {
-  // Members of Objective-C protocols should be dynamically dispatched.
-  if (auto *protoDecl = dyn_cast<ProtocolDecl>(storage->getDeclContext()))
-    return protoDecl->isObjC();
-
-  // C functions imported as members should be referenced as C functions.
-  if (storage->getGetter()->isImportAsMember())
-    return true;
-  
-  // Otherwise, favor native entry points for direct accesses.
-  if (isDirectUse)
-    return false;
-  
-  return storage->requiresForeignGetterAndSetter();
-}
-
-SILDeclRef SILGenFunction::getGetterDeclRef(AbstractStorageDecl *storage,
-                                            bool isDirectUse) {
-  // Use the ObjC entry point
-  return SILDeclRef(storage->getGetter(), SILDeclRef::Kind::Func)
-    .asForeign(shouldReferenceForeignAccessor(storage, isDirectUse));
+SILDeclRef SILGenFunction::getGetterDeclRef(AbstractStorageDecl *storage) {
+  auto *getter = storage->getGetter();
+  return SILDeclRef(getter, SILDeclRef::Kind::Func)
+    .asForeign(requiresForeignEntryPoint(getter));
 }
 
 /// Emit a call to a getter.
@@ -5031,10 +5013,10 @@ emitGetAccessor(SILLocation loc, SILDeclRef get,
   return emission.apply(c);
 }
 
-SILDeclRef SILGenFunction::getSetterDeclRef(AbstractStorageDecl *storage,
-                                            bool isDirectUse) {
-  return SILDeclRef(storage->getSetter(), SILDeclRef::Kind::Func)
-    .asForeign(shouldReferenceForeignAccessor(storage, isDirectUse));
+SILDeclRef SILGenFunction::getSetterDeclRef(AbstractStorageDecl *storage) {
+  auto *setter = storage->getSetter();
+  return SILDeclRef(setter, SILDeclRef::Kind::Func)
+    .asForeign(requiresForeignEntryPoint(setter));
 }
 
 void SILGenFunction::emitSetAccessor(SILLocation loc, SILDeclRef set,
@@ -5097,8 +5079,7 @@ void SILGenFunction::emitSetAccessor(SILLocation loc, SILDeclRef set,
 }
 
 SILDeclRef
-SILGenFunction::getMaterializeForSetDeclRef(AbstractStorageDecl *storage,
-                                            bool isDirectUse) {
+SILGenFunction::getMaterializeForSetDeclRef(AbstractStorageDecl *storage) {
   return SILDeclRef(storage->getMaterializeForSetFunc(),
                     SILDeclRef::Kind::Func);
 }
@@ -5176,8 +5157,7 @@ emitMaterializeForSetAccessor(SILLocation loc, SILDeclRef materializeForSet,
 }
 
 SILDeclRef SILGenFunction::getAddressorDeclRef(AbstractStorageDecl *storage,
-                                               AccessKind accessKind,
-                                               bool isDirectUse) {
+                                               AccessKind accessKind) {
   FuncDecl *addressorFunc = storage->getAddressorForAccess(accessKind);
   return SILDeclRef(addressorFunc, SILDeclRef::Kind::Func);
 }