swiftlang · shahmishal · Mar 26, 2019 · Mar 22, 2019
diff --git a/include/swift/AST/Module.h b/include/swift/AST/Module.h
@@ -810,6 +810,14 @@ class FileUnit : public DeclContext {
     return nullptr;
   }
 
+  /// Returns the name to use when referencing entities in this file.
+  ///
+  /// Usually this is the module name itself, but certain Clang features allow
+  /// substituting another name instead.
+  virtual StringRef getExportedModuleName() const {
+    return getParentModule()->getName().str();
+  }
+
   /// Traverse the decls within this file.
   ///
   /// \returns true if traversal was aborted, false if it completed

diff --git a/include/swift/AST/PrintOptions.h b/include/swift/AST/PrintOptions.h
@@ -185,6 +185,12 @@ struct PrintOptions {
   /// type might be ambiguous.
   bool FullyQualifiedTypesIfAmbiguous = false;
 
+  /// If true, printed module names will use the "exported" name, which may be
+  /// different from the regular name.
+  ///
+  /// \see FileUnit::getExportedModuleName
+  bool UseExportedModuleNames = false;
+
   /// Print Swift.Array and Swift.Optional with sugared syntax
   /// ([] and ?), even if there are no sugar type nodes.
   bool SynthesizeSugarOnTypes = false;

diff --git a/include/swift/ClangImporter/ClangModule.h b/include/swift/ClangImporter/ClangModule.h
@@ -62,7 +62,7 @@ class ClangModuleUnit final : public LoadedFile {
   /// Retrieve the "exported" name of the module, which is usually the module
   /// name, but might be the name of the public module through which this
   /// (private) module is re-exported.
-  std::string getExportedModuleName() const;
+  StringRef getExportedModuleName() const override;
 
   virtual bool isSystemModule() const override;
 

diff --git a/lib/AST/ASTPrinter.cpp b/lib/AST/ASTPrinter.cpp
@@ -99,6 +99,7 @@ PrintOptions PrintOptions::printParseableInterfaceFile() {
   result.TypeDefinitions = true;
   result.PrintIfConfig = false;
   result.FullyQualifiedTypes = true;
+  result.UseExportedModuleNames = true;
   result.AllowNullTypes = false;
   result.SkipImports = true;
   result.OmitNameOfInaccessibleProperties = true;
@@ -3338,8 +3339,14 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
 
   template <typename T>
   void printModuleContext(T *Ty) {
-    ModuleDecl *Mod = Ty->getDecl()->getModuleContext();
-    Printer.printModuleRef(Mod, Mod->getName());
+    FileUnit *File = cast<FileUnit>(Ty->getDecl()->getModuleScopeContext());
+    ModuleDecl *Mod = File->getParentModule();
+
+    Identifier Name = Mod->getName();
+    if (Options.UseExportedModuleNames)
+      Name = Mod->getASTContext().getIdentifier(File->getExportedModuleName());
+
+    Printer.printModuleRef(Mod, Name);
     Printer << ".";
   }
 

diff --git a/lib/ClangImporter/ClangImporter.cpp b/lib/ClangImporter/ClangImporter.cpp
@@ -3120,7 +3120,7 @@ clang::ASTContext &ClangModuleUnit::getClangASTContext() const {
   return owner.getClangASTContext();
 }
 
-std::string ClangModuleUnit::getExportedModuleName() const {
+StringRef ClangModuleUnit::getExportedModuleName() const {
   if (clangModule && !clangModule->ExportAsModule.empty())
     return clangModule->ExportAsModule;
 

diff --git a/lib/Serialization/Deserialization.cpp b/lib/Serialization/Deserialization.cpp
@@ -1147,7 +1147,7 @@ static bool isReExportedToModule(const ValueDecl *value,
       = dyn_cast<ClangModuleUnit>(valueDC->getModuleScopeContext());
   if (!fromClangModule)
     return false;
-  std::string exportedName = fromClangModule->getExportedModuleName();
+  StringRef exportedName = fromClangModule->getExportedModuleName();
 
   auto toClangModule
       = dyn_cast<ClangModuleUnit>(expectedModule->getFiles().front());

diff --git a/lib/Serialization/ModuleFile.cpp b/lib/Serialization/ModuleFile.cpp
@@ -25,7 +25,6 @@
 #include "swift/AST/USRGeneration.h"
 #include "swift/Basic/Range.h"
 #include "swift/ClangImporter/ClangImporter.h"
-#include "swift/ClangImporter/ClangModule.h"
 #include "swift/Serialization/BCReadingExtras.h"
 #include "swift/Serialization/SerializedModuleLoader.h"
 #include "llvm/ADT/StringExtras.h"
@@ -1842,17 +1841,8 @@ void ModuleFile::loadExtensions(NominalTypeDecl *nominal) {
   }
 
   if (nominal->getParent()->isModuleScopeContext()) {
-    auto parentModule = nominal->getParentModule();
-    StringRef moduleName = parentModule->getName().str();
-
-    // If the originating module is a private module whose interface is
-    // re-exported via public module, check the name of the public module.
-    std::string exportedModuleName;
-    if (auto clangModuleUnit =
-            dyn_cast<ClangModuleUnit>(parentModule->getFiles().front())) {
-      exportedModuleName = clangModuleUnit->getExportedModuleName();
-      moduleName = exportedModuleName;
-    }
+    auto parentFile = cast<FileUnit>(nominal->getParent());
+    StringRef moduleName = parentFile->getExportedModuleName();
 
     for (auto item : *iter) {
       if (item.first != moduleName)

diff --git a/lib/Serialization/Serialization.cpp b/lib/Serialization/Serialization.cpp
@@ -180,7 +180,7 @@ namespace {
     int32_t getNameDataForBase(const NominalTypeDecl *nominal,
                                StringRef *dataToWrite = nullptr) {
       if (nominal->getDeclContext()->isModuleScopeContext())
-        return -Serializer.addModuleRef(nominal->getParentModule());
+        return -Serializer.addContainingModuleRef(nominal->getDeclContext());
 
       auto &mangledName = MangledNameCache[nominal];
       if (mangledName.empty())
@@ -731,7 +731,12 @@ IdentifierID Serializer::addFilename(StringRef filename) {
   return addUniquedString(filename).second;
 }
 
-IdentifierID Serializer::addModuleRef(const ModuleDecl *M) {
+IdentifierID Serializer::addContainingModuleRef(const DeclContext *DC) {
+  assert(!isa<ModuleDecl>(DC) &&
+         "References should be to things within modules");
+  const FileUnit *file = cast<FileUnit>(DC->getModuleScopeContext());
+  const ModuleDecl *M = file->getParentModule();
+
   if (M == this->M)
     return CURRENT_MODULE_ID;
   if (M == this->M->getASTContext().TheBuiltinModule)
@@ -743,18 +748,10 @@ IdentifierID Serializer::addModuleRef(const ModuleDecl *M) {
   if (M == clangImporter->getImportedHeaderModule())
     return OBJC_HEADER_MODULE_ID;
 
-  // If we're referring to a member of a private module that will be
-  // re-exported via a public module, record the public module's name.
-  if (auto clangModuleUnit =
-        dyn_cast<ClangModuleUnit>(M->getFiles().front())) {
-    auto exportedModuleName =
-        M->getASTContext().getIdentifier(
-                                 clangModuleUnit->getExportedModuleName());
-    return addDeclBaseNameRef(exportedModuleName);
-  }
-
-  assert(!M->getName().empty());
-  return addDeclBaseNameRef(M->getName());
+  auto exportedModuleName = file->getExportedModuleName();
+  assert(!exportedModuleName.empty());
+  auto exportedModuleID = M->getASTContext().getIdentifier(exportedModuleName);
+  return addDeclBaseNameRef(exportedModuleID);
 }
 
 SILLayoutID Serializer::addSILLayoutRef(SILLayout *layout) {
@@ -1650,7 +1647,7 @@ Serializer::writeConformance(ProtocolConformanceRef conformanceRef,
         abbrCode,
         addDeclRef(normal->getProtocol()),
         addDeclRef(normal->getType()->getAnyNominal()),
-        addModuleRef(normal->getDeclContext()->getParentModule()));
+        addContainingModuleRef(normal->getDeclContext()));
     }
     break;
   }
@@ -1888,14 +1885,13 @@ void Serializer::writeCrossReference(const DeclContext *DC, uint32_t pathLen) {
   case DeclContextKind::EnumElementDecl:
     llvm_unreachable("cannot cross-reference this context");
 
-  case DeclContextKind::FileUnit:
-    DC = cast<FileUnit>(DC)->getParentModule();
-    LLVM_FALLTHROUGH;
-
   case DeclContextKind::Module:
+    llvm_unreachable("should only cross-reference something within a file");
+
+  case DeclContextKind::FileUnit:
     abbrCode = DeclTypeAbbrCodes[XRefLayout::Code];
     XRefLayout::emitRecord(Out, ScratchRecord, abbrCode,
-                           addModuleRef(cast<ModuleDecl>(DC)), pathLen);
+                           addContainingModuleRef(DC), pathLen);
     break;
 
   case DeclContextKind::GenericTypeDecl: {
@@ -1932,7 +1928,7 @@ void Serializer::writeCrossReference(const DeclContext *DC, uint32_t pathLen) {
       genericSig = ext->getGenericSignature()->getCanonicalSignature();
     }
     XRefExtensionPathPieceLayout::emitRecord(
-        Out, ScratchRecord, abbrCode, addModuleRef(DC->getParentModule()),
+        Out, ScratchRecord, abbrCode, addContainingModuleRef(DC),
         addGenericSignatureRef(genericSig));
     break;
   }
@@ -2025,7 +2021,7 @@ void Serializer::writeCrossReference(const Decl *D) {
   unsigned abbrCode;
 
   if (auto op = dyn_cast<OperatorDecl>(D)) {
-    writeCrossReference(op->getModuleContext(), 1);
+    writeCrossReference(op->getDeclContext(), 1);
 
     abbrCode = DeclTypeAbbrCodes[XRefOperatorOrAccessorPathPieceLayout::Code];
     auto nameID = addDeclBaseNameRef(op->getName());
@@ -2037,7 +2033,7 @@ void Serializer::writeCrossReference(const Decl *D) {
   }
 
   if (auto prec = dyn_cast<PrecedenceGroupDecl>(D)) {
-    writeCrossReference(prec->getModuleContext(), 1);
+    writeCrossReference(prec->getDeclContext(), 1);
 
     abbrCode = DeclTypeAbbrCodes[XRefOperatorOrAccessorPathPieceLayout::Code];
     auto nameID = addDeclBaseNameRef(prec->getName());

diff --git a/lib/Serialization/Serialization.h b/lib/Serialization/Serialization.h
@@ -540,13 +540,16 @@ class Serializer : public SerializerBase {
   /// Records the use of the given SILLayout.
   SILLayoutID addSILLayoutRef(SILLayout *layout);
 
-  /// Records the use of the given module.
+  /// Records the module containing \p DC.
   ///
-  /// The module's name will be scheduled for serialization if necessary.
+  /// The module's name will be scheduled for serialization if necessary. This
+  /// may not be exactly the same as the name of the module containing DC;
+  /// instead, it will match the containing file's "exported module name".
   ///
   /// \returns The ID for the identifier for the module's name, or one of the
   /// special module codes defined above.
-  IdentifierID addModuleRef(const ModuleDecl *M);
+  /// \see FileUnit::getExportedModuleName
+  IdentifierID addContainingModuleRef(const DeclContext *DC);
 
   /// Write a normal protocol conformance.
   void writeNormalConformance(const NormalProtocolConformance *conformance);

diff --git a/test/ParseableInterface/Inputs/exported-module-name-after/CoreKit.h b/test/ParseableInterface/Inputs/exported-module-name-after/CoreKit.h
@@ -0,0 +1 @@
+#import <ExportAsCoreKit.h>
diff --git a/test/ParseableInterface/Inputs/exported-module-name-after/ExportAsCoreKit.h b/test/ParseableInterface/Inputs/exported-module-name-after/ExportAsCoreKit.h
@@ -0,0 +1,3 @@
+struct CKThing {
+  long value;
+};
diff --git a/test/ParseableInterface/Inputs/exported-module-name-after/module.modulemap b/test/ParseableInterface/Inputs/exported-module-name-after/module.modulemap
@@ -0,0 +1,5 @@
+module CoreKit {
+  header "CoreKit.h"
+  header "ExportAsCoreKit.h"
+  export *
+}
diff --git a/test/ParseableInterface/Inputs/exported-module-name-before/CoreKit.h b/test/ParseableInterface/Inputs/exported-module-name-before/CoreKit.h
@@ -0,0 +1 @@
+#import <ExportAsCoreKit.h>
diff --git a/test/ParseableInterface/Inputs/exported-module-name-before/ExportAsCoreKit.h b/test/ParseableInterface/Inputs/exported-module-name-before/ExportAsCoreKit.h
@@ -0,0 +1,3 @@
+struct CKThing {
+  long value;
+};
diff --git a/test/ParseableInterface/Inputs/exported-module-name-before/module.modulemap b/test/ParseableInterface/Inputs/exported-module-name-before/module.modulemap
@@ -0,0 +1,10 @@
+module CoreKit {
+  header "CoreKit.h"
+  export *
+}
+
+module ExportAsCoreKit_BAD {
+  header "ExportAsCoreKit.h"
+  export_as CoreKit
+  export *
+}
diff --git a/test/ParseableInterface/exported-module-name.swift b/test/ParseableInterface/exported-module-name.swift
@@ -0,0 +1,19 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -typecheck -emit-parseable-module-interface-path %t/CoreKitClient.swiftinterface -module-name CoreKitClient -I %S/Inputs/exported-module-name-before %s
+// RUN: %FileCheck -implicit-check-not BAD %s < %t/CoreKitClient.swiftinterface
+
+// Test that we can rebuild it even when the "export as" module goes away.
+// RUN: %target-swift-frontend -build-module-from-parseable-interface -o %t/CoreKitClient.swiftmodule -I %S/Inputs/exported-module-name-after %t/CoreKitClient.swiftinterface
+
+// CHECK: import CoreKit
+import CoreKit
+
+// CHECK-LABEL: public struct CKThingWrapper : RawRepresentable {
+public struct CKThingWrapper: RawRepresentable {
+  public var rawValue: CKThing
+  public init(rawValue: CKThing) {
+    self.rawValue = rawValue
+  }
+  // Note that this is CoreKit.CKThing, not ExportAsCoreKit.CKThing
+  // CHECK: public typealias RawValue = CoreKit.CKThing
+} // CHECK: {{^}$}}