Serialization: Handle IfConfigDecls in ExternallyAccessibleDeclVisitor.

Author: tshortli

lib/Serialization/Serialization.cpp

@@ -3413,7 +3413,6 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
     UNREACHABLE(MacroExpansion);
     UNREACHABLE(GenericTypeParam);
     UNREACHABLE(Param);
-    UNREACHABLE(IfConfig);
     UNREACHABLE(PrecedenceGroup);
     UNREACHABLE(Operator);
 
@@ -3427,6 +3426,7 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
     // context has already been checked.
 #define UNINTERESTING(KIND)                                                    \
   bool visit##KIND##Decl(const KIND##Decl *D) { return true; }
+    UNINTERESTING(IfConfig);
     UNINTERESTING(EnumCase);
 
 #undef UNINTERESTING

test/Inputs/lazy_typecheck.swift

@@ -246,3 +246,13 @@ extension PublicGenericStruct: EmptyPublicProto where T == InternalStructForCons
 
 public typealias PublicStructAlias = PublicStruct
 typealias InternalTypeAlias = DoesNotExist // expected-error {{cannot find type 'DoesNotExist' in scope}}
+
+// MARK: - Compiler directives
+
+extension PublicStruct {
+#if FLAG
+  public static func activeMethod() {}
+#else
+  public static func inactiveMethod() -> DoesNotExist {}
+#endif
+}

test/Inputs/lazy_typecheck_client.swift

@@ -34,6 +34,7 @@ func testPublicStruct() {
   let _: Double = s.publicWrappedProperty
   let _: Double = s.$publicWrappedProperty.wrappedValue
   PublicStruct.publicStaticMethod()
+  PublicStruct.activeMethod()
 }
 
 func testPublicClass() {

test/ModuleInterface/lazy-typecheck.swift

@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
 
-// RUN: %target-swift-frontend -swift-version 5 %S/../Inputs/lazy_typecheck.swift -module-name lazy_typecheck -typecheck -emit-module-interface-path %t/lazy_typecheck.swiftinterface -enable-library-evolution -parse-as-library -package-name Package -experimental-lazy-typecheck
+// RUN: %target-swift-frontend -swift-version 5 %S/../Inputs/lazy_typecheck.swift -module-name lazy_typecheck -typecheck -emit-module-interface-path %t/lazy_typecheck.swiftinterface -enable-library-evolution -parse-as-library -package-name Package -DFLAG -experimental-lazy-typecheck
 // RUN: %FileCheck %s < %t/lazy_typecheck.swiftinterface
 
 // RUN: rm -rf %t/*.swiftmodule
@@ -103,6 +103,9 @@
 // CHECK:       }
 // CHECK:       #endif
 // CHECK:       public typealias PublicStructAlias = lazy_typecheck.PublicStruct
+// CHECK:       extension lazy_typecheck.PublicStruct {
+// CHECK:         public static func activeMethod()
+// CHECK:       }
 // CHECK:       @available(*, unavailable)
 // CHECK-NEXT:  extension lazy_typecheck.PublicGenericStruct : lazy_typecheck.EmptyPublicProto where T : _ConstraintThatIsNotPartOfTheAPIOfThisLibrary {}
 // CHECK:       extension lazy_typecheck.PublicStructIndirectlyConformingToPublicProto : lazy_typecheck.PublicProto {}

test/Serialization/serialize-external-decls-only-lazy-typecheck.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -swift-version 5 %S/../Inputs/lazy_typecheck.swift -enable-library-evolution -parse-as-library -package-name Package -typecheck -verify
-// RUN: %target-swift-frontend -swift-version 5 %S/../Inputs/lazy_typecheck.swift -module-name lazy_typecheck -emit-module -emit-module-path %t/lazy_typecheck.swiftmodule -enable-library-evolution -parse-as-library -package-name Package -experimental-lazy-typecheck -experimental-skip-all-function-bodies -experimental-serialize-external-decls-only
+// RUN: %target-swift-frontend -swift-version 5 %S/../Inputs/lazy_typecheck.swift -enable-library-evolution -parse-as-library -package-name Package -DFLAG -typecheck -verify
+// RUN: %target-swift-frontend -swift-version 5 %S/../Inputs/lazy_typecheck.swift -module-name lazy_typecheck -emit-module -emit-module-path %t/lazy_typecheck.swiftmodule -enable-library-evolution -parse-as-library -package-name Package -DFLAG -experimental-lazy-typecheck -experimental-skip-all-function-bodies -experimental-serialize-external-decls-only
 
-// RUN: %target-swift-frontend -package-name Package -typecheck -verify %S/../Inputs/lazy_typecheck_client.swift -D TEST_PACKAGE -I %t
+// RUN: %target-swift-frontend -package-name Package -typecheck -verify %S/../Inputs/lazy_typecheck_client.swift -DFLAG -I %t

test/TBD/lazy-typecheck.swift

@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: split-file %s %t
 
-// RUN: %target-swift-frontend -target arm64-apple-macosx10.13 -swift-version 5 %S/../Inputs/lazy_typecheck.swift -module-name lazy_typecheck -emit-module -emit-module-path /dev/null -emit-tbd-path %t/lazy_typecheck.tbd -enable-library-evolution -parse-as-library -package-name Package -experimental-lazy-typecheck -experimental-skip-all-function-bodies -experimental-serialize-external-decls-only
+// RUN: %target-swift-frontend -target arm64-apple-macosx10.13 -swift-version 5 %S/../Inputs/lazy_typecheck.swift -module-name lazy_typecheck -emit-module -emit-module-path /dev/null -emit-tbd-path %t/lazy_typecheck.tbd -enable-library-evolution -parse-as-library -package-name Package -DFLAG -experimental-lazy-typecheck -experimental-skip-all-function-bodies -experimental-serialize-external-decls-only
 // RUN: %llvm-readtapi %t/lazy_typecheck.tbd %t/expected.tbd
 
 // REQUIRES: OS=macosx
@@ -86,8 +86,8 @@ exports:
                        '_$s14lazy_typecheck11PublicClassCfD', '_$s14lazy_typecheck11PublicClassCfd',
                        '_$s14lazy_typecheck11PublicProtoMp', '_$s14lazy_typecheck11PublicProtoP3reqSiyFTj',
                        '_$s14lazy_typecheck11PublicProtoP3reqSiyFTq', '_$s14lazy_typecheck11PublicProtoTL',
-                       '_$s14lazy_typecheck11packageFuncSiyF', '_$s14lazy_typecheck12PublicStructV12publicMethodSiyF',
-                       '_$s14lazy_typecheck12PublicStructV14publicPropertySivM',
+                       '_$s14lazy_typecheck11packageFuncSiyF', '_$s14lazy_typecheck12PublicStructV12activeMethodyyFZ',
+                       '_$s14lazy_typecheck12PublicStructV12publicMethodSiyF', '_$s14lazy_typecheck12PublicStructV14publicPropertySivM',
                        '_$s14lazy_typecheck12PublicStructV14publicPropertySivg',
                        '_$s14lazy_typecheck12PublicStructV14publicPropertySivpMV',
                        '_$s14lazy_typecheck12PublicStructV14publicPropertySivs',