[embedded] Serialize+deserialize vtables, fix using non-generic classes from other modules in embedded Swift

lib/IRGen/GenClass.cpp

@@ -2901,6 +2901,9 @@ CanType irgen::getSuperclassForMetadata(IRGenModule &IGM, CanType type,
 
 ClassMetadataStrategy
 IRGenModule::getClassMetadataStrategy(const ClassDecl *theClass) {
+  if (Context.LangOpts.hasFeature(Feature::Embedded))
+    return ClassMetadataStrategy::Fixed;
+
   SILType selfType = getSelfType(theClass);
   auto &selfTI = getTypeInfo(selfType).as<ClassTypeInfo>();
 

lib/IRGen/GenDecl.cpp

@@ -1436,6 +1436,7 @@ void IRGenerator::emitLazyDefinitions() {
     assert(LazyWitnessTables.empty());
     assert(LazyCanonicalSpecializedMetadataAccessors.empty());
     assert(LazyMetadataAccessors.empty());
+    // LazyClassMetadata is allowed
     // LazySpecializedClassMetadata is allowed
   }
 
@@ -1446,7 +1447,9 @@ void IRGenerator::emitLazyDefinitions() {
          !LazyFunctionDefinitions.empty() || !LazyWitnessTables.empty() ||
          !LazyCanonicalSpecializedMetadataAccessors.empty() ||
          !LazyMetadataAccessors.empty() ||
-         !LazySpecializedClassMetadata.empty()) {
+         !LazyClassMetadata.empty() ||
+         !LazySpecializedClassMetadata.empty()
+         ) {
     // Emit any lazy type metadata we require.
     while (!LazyTypeMetadata.empty()) {
       NominalTypeDecl *type = LazyTypeMetadata.pop_back_val();
@@ -1544,6 +1547,12 @@ void IRGenerator::emitLazyDefinitions() {
       emitLazyMetadataAccessor(*IGM.get(), nominal);
     }
 
+    while (!LazyClassMetadata.empty()) {
+      CanType classType = LazyClassMetadata.pop_back_val();
+      CurrentIGMPtr IGM = getGenModule(classType->getClassOrBoundGenericClass());
+      emitLazyClassMetadata(*IGM.get(), classType);
+    }
+
     while (!LazySpecializedClassMetadata.empty()) {
       CanType classType = LazySpecializedClassMetadata.pop_back_val();
       CurrentIGMPtr IGM = getGenModule(classType->getClassOrBoundGenericClass());
@@ -1636,6 +1645,12 @@ bool IRGenerator::hasLazyMetadata(TypeDecl *type) {
   return isLazy;
 }
 
+void IRGenerator::noteUseOfClassMetadata(CanType classType) {
+  if (LazilyEmittedClassMetadata.insert(classType.getPointer()).second) {
+    LazyClassMetadata.push_back(classType);
+  }
+}
+
 void IRGenerator::noteUseOfSpecializedClassMetadata(CanType classType) {
   if (LazilyEmittedSpecializedClassMetadata.insert(classType.getPointer()).second) {
     LazySpecializedClassMetadata.push_back(classType);
@@ -5151,6 +5166,8 @@ IRGenModule::getAddrOfTypeMetadata(CanType concreteType,
       if (auto *classDecl = dyn_cast<ClassDecl>(nominal)) {
         if (classDecl->isGenericContext()) {
           IRGen.noteUseOfSpecializedClassMetadata(concreteType);
+        } else {
+          IRGen.noteUseOfClassMetadata(concreteType);
         }
       }
     }

lib/IRGen/GenMeta.cpp

@@ -4996,35 +4996,65 @@ void irgen::emitClassMetadata(IRGenModule &IGM, ClassDecl *classDecl,
   }
 }
 
-void irgen::emitEmbeddedClassMetadata(IRGenModule &IGM, ClassDecl *classDecl,
-                                      const ClassLayout &fragileLayout) {
-  PrettyStackTraceDecl stackTraceRAII("emitting metadata for", classDecl);
-  assert(!classDecl->isForeign());
+static void emitEmbeddedVTable(IRGenModule &IGM, CanType classTy,
+                               SILVTable *vtable) {
+  SILType classType = SILType::getPrimitiveObjectType(classTy);
+  auto &classTI = IGM.getTypeInfo(classType).as<ClassTypeInfo>();
 
-  // Set up a dummy global to stand in for the metadata object while we produce
-  // relative references.
-  ConstantInitBuilder builder(IGM);
-  auto init = builder.beginStruct();
-  init.setPacked(true);
+  auto &fragileLayout =
+      classTI.getClassLayout(IGM, classType, /*forBackwardDeployment=*/true);
 
+  ClassDecl *classDecl = classType.getClassOrBoundGenericClass();
   auto strategy = IGM.getClassMetadataStrategy(classDecl);
   assert(strategy == ClassMetadataStrategy::FixedOrUpdate ||
          strategy == ClassMetadataStrategy::Fixed);
 
-  FixedClassMetadataBuilder metadataBuilder(IGM, classDecl, init,
-                                            fragileLayout);
-  metadataBuilder.layout();
-  bool canBeConstant = metadataBuilder.canBeConstant();
+  ConstantInitBuilder initBuilder(IGM);
+  auto init = initBuilder.beginStruct();
+  init.setPacked(true);
 
-  CanType declaredType = classDecl->getDeclaredType()->getCanonicalType();
+  assert(vtable);
+
+  FixedClassMetadataBuilder builder(IGM, classDecl, init, fragileLayout,
+                                    vtable);
+  builder.layout();
+  bool canBeConstant = builder.canBeConstant();
 
   StringRef section{};
-  bool isPattern = false;
-  auto var = IGM.defineTypeMetadata(declaredType, isPattern, canBeConstant,
+  auto var = IGM.defineTypeMetadata(classTy, /*isPattern*/ false, canBeConstant,
                                     init.finishAndCreateFuture(), section);
   (void)var;
 }
 
+void irgen::emitEmbeddedClassMetadata(IRGenModule &IGM, ClassDecl *classDecl,
+                                      const ClassLayout &fragileLayout) {
+  PrettyStackTraceDecl stackTraceRAII("emitting metadata for", classDecl);
+  assert(!classDecl->isForeign());
+  CanType declaredType = classDecl->getDeclaredType()->getCanonicalType();
+  SILVTable *vtable = IGM.getSILModule().lookUpVTable(classDecl);
+  emitEmbeddedVTable(IGM, declaredType, vtable);
+}
+
+void irgen::emitLazyClassMetadata(IRGenModule &IGM, CanType classTy) {
+  // Might already be emitted, skip if that's the case.
+  auto entity =
+      LinkEntity::forTypeMetadata(classTy, TypeMetadataAddress::AddressPoint);
+  auto *existingVar = cast<llvm::GlobalVariable>(
+      IGM.getAddrOfLLVMVariable(entity, ConstantInit(), DebugTypeInfo()));
+  if (!existingVar->isDeclaration()) {
+    return;
+  }
+
+  auto &context = classTy->getNominalOrBoundGenericNominal()->getASTContext();
+  PrettyStackTraceType stackTraceRAII(
+    context, "emitting lazy class metadata for", classTy);
+
+  SILType classType = SILType::getPrimitiveObjectType(classTy);
+  ClassDecl *classDecl = classType.getClassOrBoundGenericClass();
+  SILVTable *vtable = IGM.getSILModule().lookUpVTable(classDecl);
+  emitEmbeddedVTable(IGM, classTy, vtable);
+}
+
 void irgen::emitLazySpecializedClassMetadata(IRGenModule &IGM,
                                              CanType classTy) {
   auto &context = classTy->getNominalOrBoundGenericNominal()->getASTContext();
@@ -5032,28 +5062,8 @@ void irgen::emitLazySpecializedClassMetadata(IRGenModule &IGM,
     context, "emitting lazy specialized class metadata for", classTy);
 
   SILType classType = SILType::getPrimitiveObjectType(classTy);
-  auto &classTI = IGM.getTypeInfo(classType).as<ClassTypeInfo>();
-  
-  auto &fragileLayout =
-    classTI.getClassLayout(IGM, classType, /*forBackwardDeployment=*/true);
-
-  ClassDecl *classDecl = classType.getClassOrBoundGenericClass();
-
-  ConstantInitBuilder initBuilder(IGM);
-  auto init = initBuilder.beginStruct();
-  init.setPacked(true);
-
   SILVTable *vtable = IGM.getSILModule().lookUpSpecializedVTable(classType);
-  assert(vtable);
-
-  FixedClassMetadataBuilder builder(IGM, classDecl, init, fragileLayout, vtable);
-  builder.layout();
-  bool canBeConstant = builder.canBeConstant();
-
-  StringRef section{};
-  auto var = IGM.defineTypeMetadata(classTy, false, canBeConstant,
-                                    init.finishAndCreateFuture(), section);
-  (void)var;
+  emitEmbeddedVTable(IGM, classTy, vtable);
 }
 
 void irgen::emitSpecializedGenericClassMetadata(IRGenModule &IGM, CanType type,

lib/IRGen/GenMeta.h

@@ -83,6 +83,8 @@ namespace irgen {
   /// Emit the type metadata accessor for a type for which it might be used.
   void emitLazyMetadataAccessor(IRGenModule &IGM, NominalTypeDecl *type);
 
+  void emitLazyClassMetadata(IRGenModule &IGM, CanType classType);
+
   void emitLazySpecializedClassMetadata(IRGenModule &IGM, CanType classType);
 
   void emitLazyCanonicalSpecializedMetadataAccessor(IRGenModule &IGM,

lib/IRGen/IRGenModule.h

@@ -327,6 +327,10 @@ private:
   /// The queue of lazy witness tables to emit.
   llvm::SmallVector<SILWitnessTable *, 4> LazyWitnessTables;
 
+  llvm::SmallVector<CanType, 4> LazyClassMetadata;
+
+  llvm::SmallPtrSet<TypeBase *, 4> LazilyEmittedClassMetadata;
+
   llvm::SmallVector<CanType, 4> LazySpecializedClassMetadata;
 
   llvm::SmallPtrSet<TypeBase *, 4> LazilyEmittedSpecializedClassMetadata;
@@ -476,6 +480,7 @@ public:
     }
   }
 
+  void noteUseOfClassMetadata(CanType classType);
   void noteUseOfSpecializedClassMetadata(CanType classType);
 
   void noteUseOfTypeMetadata(NominalTypeDecl *type) {

lib/SIL/IR/SILModule.cpp

@@ -518,6 +518,17 @@ SILVTable *SILModule::lookUpVTable(const ClassDecl *C,
   if (!Vtbl)
     return nullptr;
 
+  if (C->walkSuperclasses([&](ClassDecl *S) {
+    SILVTable *Vtbl = getSILLoader()->lookupVTable(S);
+    if (!Vtbl) {
+      return TypeWalker::Action::Stop;
+    }
+    VTableMap[C] = Vtbl;
+    return TypeWalker::Action::Continue;
+  })) {
+    return nullptr;
+  }
+
   // If we succeeded, map C -> VTbl in the table and return VTbl.
   VTableMap[C] = Vtbl;
   return Vtbl;

lib/SILOptimizer/IPO/CrossModuleOptimization.cpp

@@ -611,6 +611,30 @@ void CrossModuleOptimization::makeDeclUsableFromInline(ValueDecl *decl) {
     auto &ctx = decl->getASTContext();
     auto *attr = new (ctx) UsableFromInlineAttr(/*implicit=*/true);
     decl->getAttrs().add(attr);
+
+    if (everything) {
+      // Serialize vtables, their superclass vtables, and make all vfunctions
+      // usable from inline.
+      if (auto *classDecl = dyn_cast<ClassDecl>(decl)) {
+        auto *vTable = M.lookUpVTable(classDecl);
+        vTable->setSerialized(IsSerialized);
+        for (auto &entry : vTable->getEntries()) {
+          makeFunctionUsableFromInline(entry.getImplementation());
+        }
+
+        classDecl->walkSuperclasses([&](ClassDecl *superClassDecl) {
+          auto *vTable = M.lookUpVTable(superClassDecl);
+          if (!vTable) {
+            return TypeWalker::Action::Stop;
+          }
+          vTable->setSerialized(IsSerialized);
+          for (auto &entry : vTable->getEntries()) {
+            makeFunctionUsableFromInline(entry.getImplementation());
+          }
+          return TypeWalker::Action::Continue;
+        });
+      }
+    }
   }
   if (auto *nominalCtx = dyn_cast<NominalTypeDecl>(decl->getDeclContext())) {
     makeDeclUsableFromInline(nominalCtx);

test/embedded/modules-classes.swift

@@ -0,0 +1,39 @@
+// RUN: %empty-directory(%t)
+// RUN: %{python} %utils/split_file.py -o %t %s
+
+// RUN: %target-swift-frontend -emit-module -o %t/MyModule.swiftmodule %t/MyModule.swift %S/Inputs/print.swift -enable-experimental-feature Embedded -parse-as-library
+// RUN: %target-swift-frontend -c -I %t %t/Main.swift -enable-experimental-feature Embedded -o %t/a.o
+// RUN: %target-clang -x c -c %S/Inputs/print.c -o %t/print.o
+// RUN: %target-clang %t/a.o %t/print.o -o %t/a.out
+// RUN: %target-run %t/a.out | %FileCheck %s
+
+// REQUIRES: executable_test
+// REQUIRES: VENDOR=apple
+// REQUIRES: OS=macosx
+
+// BEGIN MyModule.swift
+
+internal class BaseClass {
+
+}
+
+final internal class MyClass: BaseClass {
+  func foo() { print("MyClass.foo") }
+}
+
+public func foo() {
+  let o = MyClass()
+  o.foo()
+}
+
+// BEGIN Main.swift
+
+import MyModule
+
+func test() {
+  foo()
+}
+
+test()
+
+// CHECK: MyClass.foo