Merge pull request #60472 from hyp/eng/generic-value-types

[interop][SwiftToCxx] pass&return value types to/from generic functions

Author: hyp

lib/PrintAsClang/PrintClangClassType.cpp

@@ -94,47 +94,8 @@ void ClangClassTypePrinter::printClassTypeDecl(
         os << "};\n";
       });
 
-  // FIXME: avoid popping out of the module's namespace here.
-  os << "} // end namespace \n\n";
-  os << "namespace swift {\n";
-
-  os << "#pragma clang diagnostic push\n";
-  os << "#pragma clang diagnostic ignored \"-Wc++17-extensions\"\n";
-  os << "template<>\n";
-  os << "static inline const constexpr bool isUsableInGenericContext<";
-  printer.printBaseName(typeDecl->getModuleContext());
-  os << "::";
-  printer.printBaseName(typeDecl);
-  os << "> = true;\n";
-  os << "#pragma clang diagnostic pop\n";
-
-  os << "template<>\n";
-  os << "inline void * _Nonnull getTypeMetadata<";
-  printer.printBaseName(typeDecl->getModuleContext());
-  os << "::";
-  printer.printBaseName(typeDecl);
-  os << ">() {\n";
-  os << "  return ";
-  printer.printBaseName(typeDecl->getModuleContext());
-  os << "::" << cxx_synthesis::getCxxImplNamespaceName()
-     << "::" << typeMetadataFuncName << "(0)._0;\n";
-  os << "}\n";
-  os << "namespace " << cxx_synthesis::getCxxImplNamespaceName() << "{\n";
-  os << "template<>\n";
-  os << "struct implClassFor<";
-  printer.printBaseName(typeDecl->getModuleContext());
-  os << "::";
-  printer.printBaseName(typeDecl);
-  os << "> { using type = ";
-  printer.printBaseName(typeDecl->getModuleContext());
-  os << "::" << cxx_synthesis::getCxxImplNamespaceName() << "::";
-  printCxxImplClassName(os, typeDecl);
-  os << "; };\n";
-  os << "} // namespace\n";
-  os << "} // namespace swift\n";
-  os << "\nnamespace ";
-  printer.printBaseName(typeDecl->getModuleContext());
-  os << " {\n";
+  ClangValueTypePrinter::printTypeGenericTraits(os, typeDecl,
+                                                typeMetadataFuncName);
 }
 
 void ClangClassTypePrinter::printClassTypeReturnScaffold(

lib/PrintAsClang/PrintClangFunction.cpp

@@ -451,13 +451,8 @@ void DeclAndTypeClangFunctionPrinter::printCxxToCFunctionParameterUse(
     if (type->getAs<ArchetypeType>() && type->getAs<ArchetypeType>()
                                             ->getInterfaceType()
                                             ->is<GenericTypeParamType>()) {
-      // FIXME: NEED to handle boxed resilient type.
-      // os << "swift::" << cxx_synthesis::getCxxImplNamespaceName() <<
-      // "::getOpaquePointer(";
-      os << "reinterpret_cast<";
-      if (!isInOut)
-        os << "const ";
-      os << "void *>(&";
+      os << "swift::" << cxx_synthesis::getCxxImplNamespaceName()
+         << "::getOpaquePointer(";
       namePrinter();
       os << ')';
       return;
@@ -576,10 +571,10 @@ void DeclAndTypeClangFunctionPrinter::printCxxThunkBody(
   if (!isKnownCxxType(resultTy, typeMapping) &&
       !hasKnownOptionalNullableCxxMapping(resultTy)) {
     if (isGenericType(resultTy)) {
-      // FIXME: Support returning value types.
       std::string returnAddress;
       llvm::raw_string_ostream ros(returnAddress);
       ros << "reinterpret_cast<void *>(&returnValue)";
+      StringRef resultTyName = "T"; // FIXME
 
       os << "  if constexpr (std::is_base_of<::swift::"
          << cxx_synthesis::getCxxImplNamespaceName()
@@ -589,6 +584,14 @@ void DeclAndTypeClangFunctionPrinter::printCxxThunkBody(
       os << ";\n";
       os << "  return ::swift::" << cxx_synthesis::getCxxImplNamespaceName()
          << "::implClassFor<T>::type::makeRetained(returnValue);\n";
+      os << "  } else if constexpr (::swift::"
+         << cxx_synthesis::getCxxImplNamespaceName() << "::isValueType<"
+         << resultTyName << ">) {\n";
+      os << "  return ::swift::" << cxx_synthesis::getCxxImplNamespaceName()
+         << "::implClassFor<" << resultTyName
+         << ">::type::returnNewValue([&](void * _Nonnull returnValue) {\n";
+      printCallToCFunc(/*additionalParam=*/StringRef("returnValue"));
+      os << ";\n  });\n";
       os << "  } else {\n";
       os << "  T returnValue;\n";
       printCallToCFunc(/*additionalParam=*/StringRef(ros.str()));

lib/PrintAsClang/PrintClangValueType.cpp

@@ -152,7 +152,8 @@ void ClangValueTypePrinter::printValueTypeDecl(
   if (isOpaqueLayout) {
     os << "    _storage = ";
     printer.printSwiftImplQualifier();
-    os << cxx_synthesis::getCxxOpaqueStorageClassName() << "(vwTable);\n";
+    os << cxx_synthesis::getCxxOpaqueStorageClassName()
+       << "(vwTable->size, vwTable->getAlignment());\n";
   }
   os << "    vwTable->initializeWithCopy(_getOpaquePointer(), const_cast<char "
         "*>(other._getOpaquePointer()), metadata._0);\n";
@@ -172,10 +173,12 @@ void ClangValueTypePrinter::printValueTypeDecl(
   // Print out private default constructor.
   os << "  inline ";
   printer.printBaseName(typeDecl);
+  // FIXME: make noexcept.
   if (isOpaqueLayout) {
     os << "(";
     printer.printSwiftImplQualifier();
-    os << "ValueWitnessTable * _Nonnull vwTable) : _storage(vwTable) {}\n";
+    os << "ValueWitnessTable * _Nonnull vwTable) : _storage(vwTable->size, "
+          "vwTable->getAlignment()) {}\n";
   } else {
     os << "() {}\n";
   }
@@ -281,6 +284,8 @@ void ClangValueTypePrinter::printValueTypeDecl(
 
   if (!isOpaqueLayout)
     printCValueTypeStorageStruct(cPrologueOS, typeDecl, *typeSizeAlign);
+
+  printTypeGenericTraits(os, typeDecl, typeMetadataFuncName);
 }
 
 /// Print the name of the C stub struct for passing/returning a value type
@@ -456,3 +461,68 @@ void ClangValueTypePrinter::printValueTypeDirectReturnScaffold(
   os << ");\n";
   os << "  });\n";
 }
+
+void ClangValueTypePrinter::printTypeGenericTraits(
+    raw_ostream &os, const NominalTypeDecl *typeDecl,
+    StringRef typeMetadataFuncName) {
+  ClangSyntaxPrinter printer(os);
+  // FIXME: avoid popping out of the module's namespace here.
+  os << "} // end namespace \n\n";
+  os << "namespace swift {\n";
+
+  os << "#pragma clang diagnostic push\n";
+  os << "#pragma clang diagnostic ignored \"-Wc++17-extensions\"\n";
+  os << "template<>\n";
+  os << "static inline const constexpr bool isUsableInGenericContext<";
+  printer.printBaseName(typeDecl->getModuleContext());
+  os << "::";
+  printer.printBaseName(typeDecl);
+  os << "> = true;\n";
+  os << "template<>\n";
+  os << "inline void * _Nonnull getTypeMetadata<";
+  printer.printBaseName(typeDecl->getModuleContext());
+  os << "::";
+  printer.printBaseName(typeDecl);
+  os << ">() {\n";
+  os << "  return ";
+  printer.printBaseName(typeDecl->getModuleContext());
+  os << "::" << cxx_synthesis::getCxxImplNamespaceName()
+     << "::" << typeMetadataFuncName << "(0)._0;\n";
+  os << "}\n";
+
+  os << "namespace " << cxx_synthesis::getCxxImplNamespaceName() << "{\n";
+
+  if (!isa<ClassDecl>(typeDecl)) {
+    os << "template<>\n";
+    os << "static inline const constexpr bool isValueType<";
+    printer.printBaseName(typeDecl->getModuleContext());
+    os << "::";
+    printer.printBaseName(typeDecl);
+    os << "> = true;\n";
+    if (typeDecl->isResilient()) {
+      os << "template<>\n";
+      os << "static inline const constexpr bool isOpaqueLayout<";
+      printer.printBaseName(typeDecl->getModuleContext());
+      os << "::";
+      printer.printBaseName(typeDecl);
+      os << "> = true;\n";
+    }
+  }
+
+        os << "template<>\n";
+        os << "struct implClassFor<";
+        printer.printBaseName(typeDecl->getModuleContext());
+        os << "::";
+        printer.printBaseName(typeDecl);
+        os << "> { using type = ";
+        printer.printBaseName(typeDecl->getModuleContext());
+        os << "::" << cxx_synthesis::getCxxImplNamespaceName() << "::";
+        printCxxImplClassName(os, typeDecl);
+        os << "; };\n";
+        os << "} // namespace\n";
+        os << "#pragma clang diagnostic pop\n";
+        os << "} // namespace swift\n";
+        os << "\nnamespace ";
+        printer.printBaseName(typeDecl->getModuleContext());
+        os << " {\n";
+}

lib/PrintAsClang/PrintClangValueType.h

@@ -94,6 +94,10 @@ class ClangValueTypePrinter {
       StringRef metadataVarName = "metadata",
       StringRef vwTableVarName = "vwTable");
 
+  static void printTypeGenericTraits(raw_ostream &os,
+                                     const NominalTypeDecl *typeDecl,
+                                     StringRef typeMetadataFuncName);
+
 private:
   /// Prints out the C stub name used to pass/return value directly for the
   /// given value type.

lib/PrintAsClang/PrintSwiftToClangCoreScaffold.cpp

@@ -111,6 +111,8 @@ static void printValueWitnessTable(raw_ostream &os) {
 #define VOID_TYPE "void"
 #include "swift/ABI/ValueWitness.def"
 
+  membersOS << "\n  constexpr size_t getAlignment() const { return (flags & "
+            << TargetValueWitnessFlags<uint64_t>::AlignmentMask << ") + 1; }\n";
   os << "\nstruct ValueWitnessTable {\n" << membersOS.str() << "};\n\n";
   membersOS.str().clear();
 
@@ -154,43 +156,7 @@ static void printTypeMetadataResponseType(SwiftToClangInteropContext &ctx,
                  funcSig.parameterTypes[0]);
 }
 
-static void printSwiftResilientStorageClass(raw_ostream &os) {
-  auto name = cxx_synthesis::getCxxOpaqueStorageClassName();
-  static_assert(TargetValueWitnessFlags<uint64_t>::AlignmentMask ==
-                    TargetValueWitnessFlags<uint32_t>::AlignmentMask,
-                "alignment mask doesn't match");
-  os << "/// Container for an opaque Swift value, like resilient struct.\n";
-  os << "class " << name << " {\n";
-  os << "public:\n";
-  os << "  inline " << name << "() noexcept : storage(nullptr) { }\n";
-  os << "  inline " << name
-     << "(ValueWitnessTable * _Nonnull vwTable) noexcept : storage("
-        "reinterpret_cast<char *>(opaqueAlloc(vwTable->size, (vwTable->flags &"
-     << TargetValueWitnessFlags<uint64_t>::AlignmentMask << ") + 1))) { }\n";
-  os << "  inline " << name << "(" << name
-     << "&& other) noexcept : storage(other.storage) { other.storage = "
-        "nullptr; }\n";
-  os << "  inline " << name << "(const " << name << "&) noexcept = delete;\n";
-  os << "  inline ~" << name
-     << "() noexcept { if (storage) { opaqueFree(static_cast<char "
-        "* _Nonnull>(storage)); } }\n";
-  os << "  void operator =(" << name
-     << "&& other) noexcept { auto temp = storage; storage = other.storage; "
-        "other.storage = temp; }\n";
-  os << "  void operator =(const " << name << "&) noexcept = delete;\n";
-  os << "  inline char * _Nonnull getOpaquePointer() noexcept { return "
-        "static_cast<char "
-        "* _Nonnull>(storage); }\n";
-  os << "  inline const char * _Nonnull getOpaquePointer() const noexcept { "
-        "return "
-        "static_cast<char * _Nonnull>(storage); }\n";
-  os << "private:\n";
-  os << "  char * _Nullable storage;\n";
-  os << "};\n";
-}
-
 void printCxxNaiveException(raw_ostream &os) {
-  os << "\n";
   os << "/// Naive exception class that should be thrown\n";
   os << "class NaiveException {\n";
   os << "public:\n";
@@ -273,7 +239,6 @@ void swift::printSwiftToClangCoreScaffold(SwiftToClangInteropContext &ctx,
                                             /*isCForwardDefinition=*/true);
           });
           os << "\n";
-          printSwiftResilientStorageClass(os);
           printCxxNaiveException(os);
         });
     os << "\n";

stdlib/public/SwiftShims/_SwiftCxxInteroperability.h

@@ -53,6 +53,42 @@ inline void opaqueFree(void *_Nonnull p) noexcept {
 #endif
 }
 
+/// Base class for a container for an opaque Swift value, like resilient struct.
+class OpaqueStorage {
+public:
+  inline OpaqueStorage() noexcept : storage(nullptr) {}
+  inline OpaqueStorage(size_t size, size_t alignment) noexcept
+      : storage(reinterpret_cast<char *>(opaqueAlloc(size, alignment))) {}
+  inline OpaqueStorage(OpaqueStorage &&other) noexcept
+      : storage(other.storage) {
+    other.storage = nullptr;
+  }
+  inline OpaqueStorage(const OpaqueStorage &) noexcept = delete;
+
+  inline ~OpaqueStorage() noexcept {
+    if (storage) {
+      opaqueFree(static_cast<char *_Nonnull>(storage));
+    }
+  }
+
+  void operator=(OpaqueStorage &&other) noexcept {
+    auto temp = storage;
+    storage = other.storage;
+    other.storage = temp;
+  }
+  void operator=(const OpaqueStorage &) noexcept = delete;
+
+  inline char *_Nonnull getOpaquePointer() noexcept {
+    return static_cast<char *_Nonnull>(storage);
+  }
+  inline const char *_Nonnull getOpaquePointer() const noexcept {
+    return static_cast<char *_Nonnull>(storage);
+  }
+
+private:
+  char *_Nullable storage;
+};
+
 /// Base class for a Swift reference counted class value.
 class RefCountedClass {
 public:
@@ -104,8 +140,6 @@ using UInt = size_t;
 template <class T>
 static inline const constexpr bool isUsableInGenericContext = false;
 
-#pragma clang diagnostic pop
-
 /// Returns the type metadat for the given Swift type T.
 template <class T> inline void *_Nonnull getTypeMetadata();
 
@@ -117,8 +151,31 @@ template <class T> struct implClassFor {
   // using type = ...;
 };
 
+/// True if the given type is a Swift value type.
+template <class T> static inline const constexpr bool isValueType = false;
+
+/// True if the given type is a Swift value type with opaque layout that can be
+/// boxed.
+template <class T> static inline const constexpr bool isOpaqueLayout = false;
+
+/// Returns the opaque pointer to the given value.
+template <class T>
+inline const void *_Nonnull getOpaquePointer(const T &value) {
+  if constexpr (isOpaqueLayout<T>)
+    return reinterpret_cast<const OpaqueStorage &>(value).getOpaquePointer();
+  return reinterpret_cast<const void *>(&value);
+}
+
+template <class T> inline void *_Nonnull getOpaquePointer(T &value) {
+  if constexpr (isOpaqueLayout<T>)
+    return reinterpret_cast<OpaqueStorage &>(value).getOpaquePointer();
+  return reinterpret_cast<void *>(&value);
+}
+
 } // namespace _impl
 
+#pragma clang diagnostic pop
+
 } // namespace swift
 #endif
 

test/Interop/SwiftToCxx/class/swift-class-in-cxx.swift

@@ -65,7 +65,6 @@ public final class ClassWithIntField {
 // CHECK-NEXT: #pragma clang diagnostic ignored "-Wc++17-extensions"
 // CHECK-NEXT: template<>
 // CHECK-NEXT: static inline const constexpr bool isUsableInGenericContext<Class::ClassWithIntField> = true;
-// CHECK-NEXT: #pragma clang diagnostic pop
 // CHECK-NEXT: template<>
 // CHECK-NEXT: inline void * _Nonnull getTypeMetadata<Class::ClassWithIntField>() {
 // CHECK-NEXT:   return Class::_impl::$s5Class0A12WithIntFieldCMa(0)._0;
@@ -74,6 +73,7 @@ public final class ClassWithIntField {
 // CHECK-NEXT: template<>
 // CHECK-NEXT: struct implClassFor<Class::ClassWithIntField> { using type = Class::_impl::_impl_ClassWithIntField; };
 // CHECK-NEXT: } // namespace
+// CHECK-NEXT: #pragma clang diagnostic pop
 // CHECK-NEXT: } // namespace swift
 // CHECK-EMPTY:
 // CHECK-NEXT: namespace Class {

test/Interop/SwiftToCxx/core/swift-impl-defs-in-cxx.swift

@@ -51,6 +51,8 @@
 // CHECK-NEXT:  size_t stride;
 // CHECK-NEXT:  unsigned flags;
 // CHECK-NEXT:  unsigned extraInhabitantCount;
+// CHECK-EMPTY:
+// CHECK-NEXT:  constexpr size_t getAlignment() const { return (flags & 255) + 1; }
 // CHECK-NEXT: };
 // CHECK-EMPTY:
 // CHECK-NEXT: using EnumValueWitnessGetEnumTagTy = int(* __ptrauth_swift_value_witness_function_pointer(41909))(const void * _Nonnull, void * _Nonnull) SWIFT_NOEXCEPT_FUNCTION_PTR;
@@ -96,22 +98,6 @@
 // CHECK-NEXT: }
 // CHECK-NEXT: #endif
 // CHECK-EMPTY:
-// CHECK-NEXT: /// Container for an opaque Swift value, like resilient struct.
-// CHECK-NEXT: class OpaqueStorage {
-// CHECK-NEXT: public:
-// CHECK-NEXT:   inline OpaqueStorage() noexcept : storage(nullptr) { }
-// CHECK-NEXT:   inline OpaqueStorage(ValueWitnessTable * _Nonnull vwTable) noexcept : storage(reinterpret_cast<char *>(opaqueAlloc(vwTable->size, (vwTable->flags &255) + 1))) { }
-// CHECK-NEXT:   inline OpaqueStorage(OpaqueStorage&& other) noexcept : storage(other.storage) { other.storage = nullptr; }
-// CHECK-NEXT:   inline OpaqueStorage(const OpaqueStorage&) noexcept = delete;
-// CHECK-NEXT:   inline ~OpaqueStorage() noexcept { if (storage) { opaqueFree(static_cast<char * _Nonnull>(storage)); } }
-// CHECK-NEXT:   void operator =(OpaqueStorage&& other) noexcept { auto temp = storage; storage = other.storage; other.storage = temp; }
-// CHECK-NEXT:   void operator =(const OpaqueStorage&) noexcept = delete;
-// CHECK-NEXT:   inline char * _Nonnull getOpaquePointer() noexcept { return static_cast<char * _Nonnull>(storage); }
-// CHECK-NEXT:   inline const char * _Nonnull getOpaquePointer() const noexcept { return static_cast<char * _Nonnull>(storage); }
-// CHECK-NEXT: private:
-// CHECK-NEXT:   char * _Nullable storage;
-// CHECK-NEXT: };
-// CHECK-EMPTY:
 // CHECK-NEXT: /// Naive exception class that should be thrown
 // CHECK-NEXT: class NaiveException {
 // CHECK-NEXT: public: