[APINotes] Initial support for tags and typedefs within namespaces

This makes it possible to apply an attribute to a C++ struct declared within a C++ namespace via API Notes.

The current implementation will fail with an assertion if a nested namespace has the same name as its parent namespace. This will be addressed in a follow-up commit.

rdar://113403829

Author: egorzhdan

clang/include/clang/APINotes/APINotesReader.h

@@ -197,14 +197,16 @@ class APINotesReader {
   /// \param name The name of the tag.
   ///
   /// \returns information about the tag, if known.
-  VersionedInfo<TagInfo> lookupTag(llvm::StringRef name);
+  VersionedInfo<TagInfo> lookupTag(std::optional<Context> context,
+                                   llvm::StringRef name);
 
   /// Look for information regarding the given typedef.
   ///
   /// \param name The name of the typedef.
   ///
   /// \returns information about the typedef, if known.
-  VersionedInfo<TypedefInfo> lookupTypedef(llvm::StringRef name);
+  VersionedInfo<TypedefInfo> lookupTypedef(std::optional<Context> context,
+                                           llvm::StringRef name);
 
   /// Look for the context ID of the given C++ namespace.
   ///

clang/include/clang/APINotes/APINotesWriter.h

@@ -105,15 +105,15 @@ class APINotesWriter {
   ///
   /// \param name The name of this tag.
   /// \param info Information about this tag.
-  void addTag(llvm::StringRef name, const TagInfo &info,
-              llvm::VersionTuple swiftVersion);
+  void addTag(std::optional<Context> context, llvm::StringRef name,
+              const TagInfo &info, llvm::VersionTuple swiftVersion);
 
   /// Add information about a typedef.
   ///
   /// \param name The name of this typedef.
   /// \param info Information about this typedef.
-  void addTypedef(llvm::StringRef name, const TypedefInfo &info,
-                  llvm::VersionTuple swiftVersion);
+  void addTypedef(std::optional<Context> context, llvm::StringRef name,
+                  const TypedefInfo &info, llvm::VersionTuple swiftVersion);
 
   /// Add module options
   void addModuleOptions(ModuleOptions opts);

clang/include/clang/APINotes/Types.h

@@ -750,6 +750,13 @@ enum class ContextKind : uint8_t {
   Namespace = 2
 };
 
+struct Context {
+  ContextID id;
+  ContextKind kind;
+
+  Context(ContextID id, ContextKind kind) : id(id), kind(kind) {}
+};
+
 /// A temporary reference to an Objective-C selector, suitable for
 /// referencing selector data on the stack.
 ///

clang/lib/APINotes/APINotesReader.cpp

@@ -485,11 +485,14 @@ namespace {
 
   /// Used to deserialize the on-disk tag table.
   class TagTableInfo
-    : public VersionedTableInfo<TagTableInfo, unsigned, TagInfo> {
+      : public VersionedTableInfo<
+            TagTableInfo, std::tuple<uint32_t, uint8_t, uint32_t>, TagInfo> {
   public:
     static internal_key_type ReadKey(const uint8_t *data, unsigned length) {
+      auto contextID = endian::readNext<uint32_t, little, unaligned>(data);
+      auto contextKind = endian::readNext<uint8_t, little, unaligned>(data);
       auto nameID = endian::readNext<IdentifierID, little, unaligned>(data);
-      return nameID;
+      return {contextID, contextKind, nameID};
     }
 
     static TagInfo readUnversioned(internal_key_type key,
@@ -513,11 +516,15 @@ namespace {
 
   /// Used to deserialize the on-disk typedef table.
   class TypedefTableInfo
-    : public VersionedTableInfo<TypedefTableInfo, unsigned, TypedefInfo> {
+      : public VersionedTableInfo<TypedefTableInfo,
+                                  std::tuple<uint32_t, uint8_t, uint32_t>,
+                                  TypedefInfo> {
   public:
     static internal_key_type ReadKey(const uint8_t *data, unsigned length) {
+      auto contextID = endian::readNext<uint32_t, little, unaligned>(data);
+      auto contextKind = endian::readNext<uint8_t, little, unaligned>(data);
       auto nameID = endian::readNext<IdentifierID, little, unaligned>(data);
-      return nameID;
+      return {contextID, contextKind, nameID};
     }
 
     static TypedefInfo readUnversioned(internal_key_type key,
@@ -1970,22 +1977,30 @@ auto APINotesReader::lookupEnumConstant(StringRef name)
   return { Impl.SwiftVersion, *known };
 }
 
-auto APINotesReader::lookupTag(StringRef name) -> VersionedInfo<TagInfo> {
+auto APINotesReader::lookupTag(std::optional<Context> context, StringRef name)
+    -> VersionedInfo<TagInfo> {
   if (!Impl.TagTable)
     return None;
 
   Optional<IdentifierID> nameID = Impl.getIdentifier(name);
   if (!nameID)
     return None;
 
-  auto known = Impl.TagTable->find(*nameID);
+  std::tuple<uint32_t, uint8_t, uint32_t> key;
+  if (context)
+    key = {context->id.Value, (uint8_t)context->kind, *nameID};
+  else
+    key = {-1, (uint8_t)-1, *nameID};
+
+  auto known = Impl.TagTable->find(key);
   if (known == Impl.TagTable->end())
     return None;
 
   return { Impl.SwiftVersion, *known };
 }
 
-auto APINotesReader::lookupTypedef(StringRef name)
+auto APINotesReader::lookupTypedef(std::optional<Context> context,
+                                   StringRef name)
     -> VersionedInfo<TypedefInfo> {
   if (!Impl.TypedefTable)
     return None;
@@ -1994,7 +2009,13 @@ auto APINotesReader::lookupTypedef(StringRef name)
   if (!nameID)
     return None;
 
-  auto known = Impl.TypedefTable->find(*nameID);
+  std::tuple<uint32_t, uint8_t, uint32_t> key;
+  if (context)
+    key = {context->id.Value, (uint8_t)context->kind, *nameID};
+  else
+    key = {-1, (uint8_t)-1, *nameID};
+
+  auto known = Impl.TypedefTable->find(key);
   if (known == Impl.TypedefTable->end())
     return None;
 

clang/lib/APINotes/APINotesWriter.cpp

@@ -111,15 +111,15 @@ class APINotesWriter::Implementation {
 
   /// Information about tags.
   ///
-  /// Indexed by the identifier ID.
-  llvm::DenseMap<unsigned,
+  /// Indexed by the context ID, contextKind, identifier ID.
+  llvm::DenseMap<std::tuple<uint32_t, uint8_t, uint32_t>,
                  llvm::SmallVector<std::pair<VersionTuple, TagInfo>, 1>>
     Tags;
 
   /// Information about typedefs.
   ///
-  /// Indexed by the identifier ID.
-  llvm::DenseMap<unsigned,
+  /// Indexed by the context ID, contextKind, identifier ID.
+  llvm::DenseMap<std::tuple<uint32_t, uint8_t, uint32_t>,
                  llvm::SmallVector<std::pair<VersionTuple, TypedefInfo>, 1>>
     Typedefs;
 
@@ -1050,16 +1050,20 @@ void APINotesWriter::Implementation::writeEnumConstantBlock(
 namespace {
   template<typename Derived, typename UnversionedDataType>
   class CommonTypeTableInfo
-    : public VersionedTableInfo<Derived, unsigned, UnversionedDataType> {
+    : public VersionedTableInfo<Derived,
+                                std::tuple<uint32_t, uint8_t, uint32_t>,
+                                UnversionedDataType> {
   public:
     using key_type_ref = typename CommonTypeTableInfo::key_type_ref;
 
     unsigned getKeyLength(key_type_ref) {
-      return sizeof(IdentifierID);
+      return sizeof(uint32_t) + sizeof(uint8_t) + sizeof(IdentifierID);
     }
     void EmitKey(raw_ostream &out, key_type_ref key, unsigned len) {
       endian::Writer writer(out, little);
-      writer.write<IdentifierID>(key);
+      writer.write<uint32_t>(std::get<0>(key));
+      writer.write<uint8_t>(std::get<1>(key));
+      writer.write<IdentifierID>(std::get<2>(key));
     }
 
     unsigned getUnversionedInfoSize(const UnversionedDataType &info) {
@@ -1323,16 +1327,28 @@ void APINotesWriter::addEnumConstant(llvm::StringRef name,
   Impl.EnumConstants[enumConstantID].push_back({swiftVersion, info});
 }
 
-void APINotesWriter::addTag(llvm::StringRef name, const TagInfo &info,
+void APINotesWriter::addTag(std::optional<Context> context,
+                            llvm::StringRef name, const TagInfo &info,
                             VersionTuple swiftVersion) {
   IdentifierID tagID = Impl.getIdentifier(name);
-  Impl.Tags[tagID].push_back({swiftVersion, info});
+  std::tuple<uint32_t, uint8_t, uint32_t> key;
+  if (context)
+    key = {context->id.Value, (uint8_t)context->kind, tagID};
+  else
+    key = {-1, (uint8_t)-1, tagID};
+  Impl.Tags[key].push_back({swiftVersion, info});
 }
 
-void APINotesWriter::addTypedef(llvm::StringRef name, const TypedefInfo &info,
+void APINotesWriter::addTypedef(std::optional<Context> context,
+                                llvm::StringRef name, const TypedefInfo &info,
                                 VersionTuple swiftVersion) {
   IdentifierID typedefID = Impl.getIdentifier(name);
-  Impl.Typedefs[typedefID].push_back({swiftVersion, info});
+  std::tuple<uint32_t, uint8_t, uint32_t> key;
+  if (context)
+    key = {context->id.Value, (uint8_t)context->kind, typedefID};
+  else
+    key = {-1, (uint8_t)-1, typedefID};
+  Impl.Typedefs[key].push_back({swiftVersion, info});
 }
 
 void APINotesWriter::addModuleOptions(ModuleOptions opts) {

clang/lib/APINotes/APINotesYAMLCompiler.cpp

@@ -997,7 +997,23 @@ namespace {
       }
     }
 
-    void convertTopLevelItems(const TopLevelItems &items,
+    void convertNamespaceContext(const Namespace &ns,
+                                 VersionTuple swiftVersion) {
+      // Write the namespace.
+      ObjCContextInfo cInfo;
+
+      if (convertCommon(ns, cInfo, ns.Name))
+        return;
+
+      ContextID clID = Writer->addObjCContext(ns.Name, ContextKind::Namespace,
+                                              cInfo, swiftVersion);
+
+      convertTopLevelItems(Context(clID, ContextKind::Namespace), ns.Items,
+                           swiftVersion);
+    }
+
+    void convertTopLevelItems(std::optional<Context> context,
+                              const TopLevelItems &items,
                               VersionTuple swiftVersion) {
       // Write all classes.
       llvm::StringSet<> knownClasses;
@@ -1023,6 +1039,18 @@ namespace {
         convertContext(pr, ContextKind::ObjCProtocol, swiftVersion);
       }
 
+      // Write all namespaces.
+      llvm::StringSet<> knownNamespaces;
+      for (const auto &ns : items.Namespaces) {
+        // Check for duplicate namespace definitions.
+        if (!knownNamespaces.insert(ns.Name).second) {
+          emitError("multiple definitions of namespace '" + ns.Name + "'");
+          continue;
+        }
+
+        convertNamespaceContext(ns, swiftVersion);
+      }
+
       // Write all global variables.
       llvm::StringSet<> knownGlobals;
       for (const auto &global : items.Globals) {
@@ -1131,7 +1159,7 @@ namespace {
           tagInfo.setFlagEnum(t.FlagEnum);          
         }
 
-        Writer->addTag(t.Name, tagInfo, swiftVersion);
+        Writer->addTag(context, t.Name, tagInfo, swiftVersion);
       }
 
       // Write all typedefs.
@@ -1148,7 +1176,7 @@ namespace {
           continue;
         typedefInfo.SwiftWrapper = t.SwiftType;
 
-        Writer->addTypedef(t.Name, typedefInfo, swiftVersion);
+        Writer->addTypedef(context, t.Name, typedefInfo, swiftVersion);
       }
     }
 
@@ -1159,7 +1187,8 @@ namespace {
       Writer = &writer;
 
       // Write the top-level items.
-      convertTopLevelItems(TheModule.TopLevel, VersionTuple());
+      convertTopLevelItems(/* context */ std::nullopt, TheModule.TopLevel,
+                           VersionTuple());
 
       if (TheModule.SwiftInferImportAsMember) {
         ModuleOptions opts;
@@ -1169,7 +1198,8 @@ namespace {
 
       // Convert the versioned information.
       for (const auto &versioned : TheModule.SwiftVersions) {
-        convertTopLevelItems(versioned.Items, versioned.Version);
+        convertTopLevelItems(/* context */ std::nullopt, versioned.Items,
+                             versioned.Version);
       }
 
       if (!ErrorOccured)

clang/lib/Sema/SemaAPINotes.cpp

@@ -812,8 +812,19 @@ void Sema::ProcessAPINotes(Decl *D) {
 
   // Globals.
   if (D->getDeclContext()->isFileContext() ||
+      D->getDeclContext()->isNamespace() ||
       D->getDeclContext()->isExternCContext() ||
       D->getDeclContext()->isExternCXXContext()) {
+    std::optional<api_notes::Context> APINotesContext;
+    if (auto NamespaceContext = dyn_cast<NamespaceDecl>(D->getDeclContext())) {
+      for (auto Reader :
+           APINotes.findAPINotes(NamespaceContext->getLocation())) {
+        if (auto id = Reader->lookupNamespaceID(NamespaceContext->getName())) {
+          APINotesContext = {*id, api_notes::ContextKind::Namespace};
+        }
+      }
+    }
+
     // Global variables.
     if (auto VD = dyn_cast<VarDecl>(D)) {
       for (auto Reader : APINotes.findAPINotes(D->getLocation())) {
@@ -883,7 +894,7 @@ void Sema::ProcessAPINotes(Decl *D) {
       }
 
       for (auto Reader : APINotes.findAPINotes(D->getLocation())) {
-        auto Info = Reader->lookupTag(LookupName);
+        auto Info = Reader->lookupTag(APINotesContext, LookupName);
         ProcessVersionedAPINotes(*this, Tag, Info);
       }
 
@@ -893,7 +904,7 @@ void Sema::ProcessAPINotes(Decl *D) {
     // Typedefs
     if (auto Typedef = dyn_cast<TypedefNameDecl>(D)) {
       for (auto Reader : APINotes.findAPINotes(D->getLocation())) {
-        auto Info = Reader->lookupTypedef(Typedef->getName());
+        auto Info = Reader->lookupTypedef(APINotesContext, Typedef->getName());
         ProcessVersionedAPINotes(*this, Typedef, Info);
       }
 

clang/test/APINotes/Inputs/Frameworks/CXXInteropKit.framework/Headers/CXXInteropKit.apinotes

@@ -12,4 +12,16 @@ Enumerators:
   SwiftName: red
 Tags:
 - Name: NSSomeEnumOptions
-  SwiftName: SomeEnum.Options
+  SwiftName: SomeEnum.Options
+- Name: char_box
+  SwiftName: InWrongContext
+Namespaces:
+- Name: Namespace1
+  Tags:
+  - Name: char_box
+    SwiftName: CharBox
+  Namespaces:
+  - Name: Nested1
+    Tags:
+    - Name: char_box
+      SwiftName: NestedCharBox

clang/test/APINotes/Inputs/Frameworks/CXXInteropKit.framework/Headers/CXXInteropKit.h

@@ -21,3 +21,11 @@ typedef NS_OPTIONS(NSUInteger, NSSomeEnumOptions) {
 	NSSomeEnumWithGreen,
 	NSSomeEnumWithBlue,
 };
+
+namespace Namespace1 {
+struct char_box { char c; };
+
+namespace Nested1 {
+struct char_box { char c; };
+} // namespace Nested1
+} // namespace Namespace1

clang/test/APINotes/objcxx-swift-name.m

@@ -2,6 +2,8 @@
 // RUN: %clang_cc1 -fmodules -fblocks -fimplicit-module-maps -fmodules-cache-path=%t/ModulesCache/CxxInterop -fdisable-module-hash -fapinotes-modules -fsyntax-only -I %S/Inputs/Headers -F %S/Inputs/Frameworks %s -x objective-c++
 // RUN: %clang_cc1 -fmodules -fblocks -fimplicit-module-maps -fmodules-cache-path=%t/ModulesCache/CxxInterop -fdisable-module-hash -fapinotes-modules -fsyntax-only -I %S/Inputs/Headers -F %S/Inputs/Frameworks %s -ast-dump -ast-dump-filter SomeClass -x objective-c++ | FileCheck %s
 // RUN: %clang_cc1 -fmodules -fblocks -fimplicit-module-maps -fmodules-cache-path=%t/ModulesCache/CxxInterop -fdisable-module-hash -fapinotes-modules -fsyntax-only -I %S/Inputs/Headers -F %S/Inputs/Frameworks %s -ast-dump -ast-dump-filter "(anonymous)" -x objective-c++ | FileCheck -check-prefix=CHECK-ANONYMOUS-ENUM %s
+// RUN: %clang_cc1 -fmodules -fblocks -fimplicit-module-maps -fmodules-cache-path=%t/ModulesCache/CxxInterop -fdisable-module-hash -fapinotes-modules -fsyntax-only -I %S/Inputs/Headers -F %S/Inputs/Frameworks %s -ast-dump -ast-dump-filter Namespace1::char_box -x objective-c++ | FileCheck -check-prefix=CHECK-STRUCT-IN-NAMESPACE %s
+// RUN: %clang_cc1 -fmodules -fblocks -fimplicit-module-maps -fmodules-cache-path=%t/ModulesCache/CxxInterop -fdisable-module-hash -fapinotes-modules -fsyntax-only -I %S/Inputs/Headers -F %S/Inputs/Frameworks %s -ast-dump -ast-dump-filter Namespace1::Nested1::char_box -x objective-c++ | FileCheck -check-prefix=CHECK-STRUCT-IN-NESTED-NAMESPACE %s
 
 #import <CXXInteropKit/CXXInteropKit.h>
 
@@ -21,3 +23,11 @@
 // CHECK-ANONYMOUS-ENUM: Dumping (anonymous):
 // CHECK-ANONYMOUS-ENUM-NEXT: EnumDecl {{.+}} imported in CXXInteropKit <undeserialized declarations> 'NSSomeEnumOptions':'unsigned long'
 // CHECK-ANONYMOUS-ENUM-NEXT: SwiftNameAttr {{.+}} <<invalid sloc>> "SomeEnum.Options"
+
+// CHECK-STRUCT-IN-NAMESPACE: Dumping Namespace1::char_box:
+// CHECK-STRUCT-IN-NAMESPACE-NEXT: CXXRecordDecl {{.+}} imported in CXXInteropKit <undeserialized declarations> struct char_box
+// CHECK-STRUCT-IN-NAMESPACE: SwiftNameAttr {{.+}} <<invalid sloc>> "CharBox"
+
+// CHECK-STRUCT-IN-NESTED-NAMESPACE: Dumping Namespace1::Nested1::char_box:
+// CHECK-STRUCT-IN-NESTED-NAMESPACE-NEXT: CXXRecordDecl {{.+}} imported in CXXInteropKit <undeserialized declarations> struct char_box
+// CHECK-STRUCT-IN-NESTED-NAMESPACE: SwiftNameAttr {{.+}} <<invalid sloc>> "NestedCharBox"