Merge pull request swiftlang#30509 from nkcsgexi/58562780

ModuleInterface: skip override keywords when overriding an invisible decl from super class

Author: nkcsgexi

include/swift/AST/Decl.h

@@ -2697,6 +2697,11 @@ class ValueDecl : public Decl {
     return !isObjC() && isDynamic();
   }
 
+  bool isEffectiveLinkageMoreVisibleThan(ValueDecl *other) const {
+    return (std::min(getEffectiveAccess(), AccessLevel::Public) >
+            std::min(other->getEffectiveAccess(), AccessLevel::Public));
+  }
+
   /// Set whether this type is 'dynamic' or not.
   void setIsDynamic(bool value);
 
@@ -5983,11 +5988,6 @@ class AbstractFunctionDecl : public GenericContext, public ValueDecl {
   /// vtable.
   bool needsNewVTableEntry() const;
 
-  bool isEffectiveLinkageMoreVisibleThan(ValueDecl *other) const {
-    return (std::min(getEffectiveAccess(), AccessLevel::Public) >
-            std::min(other->getEffectiveAccess(), AccessLevel::Public));
-  }
-
   bool isSynthesized() const {
     return Bits.AbstractFunctionDecl.Synthesized;
   }

include/swift/AST/PrintOptions.h

@@ -276,7 +276,10 @@ struct PrintOptions {
   /// Prints type variables and unresolved types in an expanded notation suitable
   /// for debugging.
   bool PrintTypesForDebugging = false;
-  
+
+  /// Whether this print option is for printing .swiftinterface file
+  bool IsForSwiftInterface = false;
+
   /// How to print opaque return types.
   enum class OpaqueReturnTypePrintingMode {
     /// 'some P1 & P2'.

lib/AST/ASTPrinter.cpp

@@ -103,6 +103,7 @@ PrintOptions PrintOptions::printSwiftInterfaceFile(bool preferTypeRepr,
                                                    bool printFullConvention,
                                                    bool printSPIs) {
   PrintOptions result;
+  result.IsForSwiftInterface = true;
   result.PrintLongAttrsOnSeparateLines = true;
   result.TypeDefinitions = true;
   result.PrintIfConfig = false;

lib/AST/Attr.cpp

@@ -750,6 +750,26 @@ bool DeclAttribute::printImpl(ASTPrinter &Printer, const PrintOptions &Options,
   case DAK_Rethrows:
   case DAK_Infix:
     return false;
+  case DAK_Override: {
+    if (!Options.IsForSwiftInterface)
+      break;
+    // When we are printing Swift interface, we have to skip the override keyword
+    // if the overriden decl is invisible from the interface. Otherwise, an error
+    // will occur while building the Swift module because the overriding decl
+    // doesn't override anything.
+    // We couldn't skip every `override` keywords becuase they change the
+    // ABI if the overriden decl is also publically visible.
+    // For public-override-internal case, having `override` doesn't have ABI
+    // implication. Thus we can skip them.
+    if (auto *VD = dyn_cast<ValueDecl>(D)) {
+      if (auto *BD = VD->getOverriddenDecl()) {
+        if (!BD->hasClangNode() &&
+            VD->isEffectiveLinkageMoreVisibleThan(BD))
+          return false;
+      }
+    }
+    break;
+  }
   default:
     break;
   }

test/ModuleInterface/skip-override-keyword.swift

@@ -0,0 +1,14 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -typecheck -module-name Foo -emit-module-interface-path %t/Foo.swiftinterface %s
+// RUN: %target-swift-frontend -compile-module-from-interface %t/Foo.swiftinterface -o %t/Foo.swiftmodule
+
+public class BaseClass {
+  var property: Int { return 1 }
+  func doSomething() { }
+  subscript(index: Int) -> Int { get { return 0 } set(newValue) {} }
+}
+public class DerivedClass: BaseClass {
+  public override var property : Int { return 0 }
+  public override func doSomething() { }
+  public override subscript(index: Int) -> Int { get {return 0} set(newValue) {} }
+}