[DebugInfo] Fix handling of @_originallyDefinedIn types

Emit an imported declaration for @_originallyDefinedIn under the real
module that these types live in.
This patch also changes the mangling for the debugger to respect
@_originallyDefinedIn.

rdar://137146961

Author: augusto2112

include/swift/AST/ASTMangler.h

@@ -348,7 +348,8 @@ class ASTMangler : public Mangler {
                                       GenericSignature signature,
                                       ResilienceExpansion expansion);
 
-  std::string mangleTypeForDebugger(Type decl, GenericSignature sig);
+  std::string mangleTypeForDebugger(Type decl, GenericSignature sig,
+                                    bool RespectOriginallyDefinedIn = false);
 
   /// Create a mangled name to be used for _typeName constant propagation.
   std::string mangleTypeForTypeName(Type type);

lib/AST/ASTMangler.cpp

@@ -712,12 +712,12 @@ static Type getTypeForDWARFMangling(Type t) {
     MakeAbstractConformanceForGenericType());
 }
 
-std::string ASTMangler::mangleTypeForDebugger(Type Ty, GenericSignature sig) {
+std::string ASTMangler::mangleTypeForDebugger(Type Ty, GenericSignature sig, bool RespectOriginallyDefinedIn) {
   PrettyStackTraceType prettyStackTrace(Ty->getASTContext(),
                                         "mangling type for debugger", Ty);
 
   DWARFMangling = true;
-  RespectOriginallyDefinedIn = false;
+  this->RespectOriginallyDefinedIn = RespectOriginallyDefinedIn;
   OptimizeProtocolNames = false;
   beginMangling();
 

lib/IRGen/IRGenDebugInfo.cpp

@@ -150,6 +150,7 @@ class IRGenDebugInfoImpl : public IRGenDebugInfo {
   llvm::DenseMap<const void *, llvm::TrackingMDNodeRef> DIModuleCache;
   llvm::StringMap<llvm::TrackingMDNodeRef> DIFileCache;
   llvm::StringMap<llvm::TrackingMDNodeRef> RuntimeErrorFnCache;
+  llvm::StringSet<> OriginallyDefinedInTypes;
   TrackingDIRefMap DIRefMap;
   TrackingDIRefMap InnerTypeCache;
   /// \}
@@ -972,7 +973,7 @@ class IRGenDebugInfoImpl : public IRGenDebugInfo {
     return SizeInBits;
   }
 
-  StringRef getMangledName(DebugTypeInfo DbgTy) {
+  StringRef getMangledName(DebugTypeInfo DbgTy, bool RespectOriginallyDefinedIn) {
     if (DbgTy.isMetadataType())
       return MetadataTypeDeclCache.find(DbgTy.getDecl()->getName().str())
           ->getKey();
@@ -1024,11 +1025,12 @@ class IRGenDebugInfoImpl : public IRGenDebugInfo {
         IGM.getSILModule());
 
     Mangle::ASTMangler Mangler;
-    std::string Result = Mangler.mangleTypeForDebugger(Ty, Sig);
+    std::string Result = Mangler.mangleTypeForDebugger(Ty, Sig, RespectOriginallyDefinedIn);
 
     // TODO(https://github.com/apple/swift/issues/57699): We currently cannot round trip some C++ types.
+    // There's no way to round trip when respecting @_originallyDefinedIn for a type.
     if (!Opts.DisableRoundTripDebugTypes &&
-        !Ty->getASTContext().LangOpts.EnableCXXInterop) {
+        !Ty->getASTContext().LangOpts.EnableCXXInterop && !RespectOriginallyDefinedIn) {
       // Make sure we can reconstruct mangled types for the debugger.
       auto &Ctx = Ty->getASTContext();
       Type Reconstructed = Demangle::getTypeForMangling(Ctx, Result, Sig);
@@ -1506,7 +1508,7 @@ createSpecializedStructOrClassType(NominalOrBoundGenericNominalType *Type,
   /// anchor any typedefs that may appear in parameters so they can be
   /// resolved in the debugger without needing to query the Swift module.
   llvm::DINodeArray
-  collectGenericParams(NominalOrBoundGenericNominalType *BGT) {
+  collectGenericParams(NominalOrBoundGenericNominalType *BGT, bool AsForwardDeclarations = false) {
 
     // Collect the generic args from the type and its parent.
     std::vector<Type> GenericArgs;
@@ -1521,7 +1523,7 @@ createSpecializedStructOrClassType(NominalOrBoundGenericNominalType *Type,
     SmallVector<llvm::Metadata *, 16> TemplateParams;
     for (auto Arg : GenericArgs) {
       DebugTypeInfo ParamDebugType;
-      if (Opts.DebugInfoLevel > IRGenDebugInfoLevel::ASTTypes)
+      if (Opts.DebugInfoLevel > IRGenDebugInfoLevel::ASTTypes && !llvm::isa<GenericTypeParamType>(Arg) && !AsForwardDeclarations)
         // For the DwarfTypes level don't generate just a forward declaration
         // for the generic type parameters.
         ParamDebugType = DebugTypeInfo::getFromTypeInfo(
@@ -1789,26 +1791,6 @@ createSpecializedStructOrClassType(NominalOrBoundGenericNominalType *Type,
     }
 
     llvm::DIType *SpecificationOf = nullptr;
-    if (auto *TypeDecl = DbgTy.getType()->getNominalOrBoundGenericNominal()) {
-      // If this is a nominal type that has the @_originallyDefinedIn attribute,
-      // IRGenDebugInfo emits a forward declaration of the type as a child
-      // of the original module, and the type with a specification pointing to
-      // the forward declaraation. We do this so LLDB has enough information to
-      // both find the type in reflection metadata (the parent module name) and
-      // find it in the swiftmodule (the module name in the type mangled name).
-      if (auto Attribute =
-              TypeDecl->getAttrs().getAttribute<OriginallyDefinedInAttr>()) {
-        auto Identifier = IGM.getSILModule().getASTContext().getIdentifier(
-            Attribute->OriginalModuleName);
-
-        void *Key = (void *)Identifier.get();
-        auto InnerScope =
-            getOrCreateModule(Key, TheCU, Attribute->OriginalModuleName, {});
-        SpecificationOf = DBuilder.createForwardDecl(
-            llvm::dwarf::DW_TAG_structure_type, TypeDecl->getNameStr(),
-            InnerScope, File, 0, llvm::dwarf::DW_LANG_Swift, 0, 0);
-      }
-    }
 
     // Here goes!
     switch (BaseTy->getKind()) {
@@ -2338,6 +2320,45 @@ createSpecializedStructOrClassType(NominalOrBoundGenericNominalType *Type,
     }
   }
 
+  /// If this is a nominal type that has the @_originallyDefinedIn
+  /// attribute, IRGenDebugInfo emits an imported declaration of the type as
+  /// a child of the real module. We do this so LLDB has enough
+  /// information to both find the type in reflection metadata (the module name
+  /// in the type's mangled name), and find it in the swiftmodule (the type's
+  /// imported declaration's parent module name).
+  void handleOriginallyDefinedIn(DebugTypeInfo DbgTy, llvm::DIType *DITy,
+                                 StringRef MangledName, llvm::DIFile *File) {
+    if (OriginallyDefinedInTypes.contains(MangledName))
+      return;
+
+    auto Type = DbgTy.getType();
+    auto *TypeDecl = Type->getNominalOrBoundGenericNominal();
+    if (!TypeDecl)
+      return;
+
+    // Force the generation of the generic type parameters as forward
+    // declarations, as those types might be annotated with
+    // @_originallyDefinedIn.
+    if (auto *BoundDecl = llvm::dyn_cast<BoundGenericType>(DbgTy.getType()))
+      collectGenericParams(BoundDecl, /*AsForwardDeclarations=*/true);
+
+    // Find the outermost type, since only those can have @_originallyDefinedIn
+    // attached to them.
+    NominalTypeDecl *ParentDecl = TypeDecl;
+    while (llvm::isa_and_nonnull<NominalTypeDecl>(ParentDecl->getParent()))
+      ParentDecl = llvm::cast<NominalTypeDecl>(ParentDecl->getParent());
+
+    auto Attribute =
+        ParentDecl->getAttrs().getAttribute<OriginallyDefinedInAttr>();
+    if (!Attribute)
+      return;
+
+    // Find the module the imported declaration should be emitted under, this is the real module the type lives under.
+    auto RealModule = getOrCreateContext(ParentDecl->getParent());
+    DBuilder.createImportedDeclaration(RealModule, DITy, File, 0, MangledName);
+    OriginallyDefinedInTypes.insert(MangledName);
+  }
+
   llvm::DIType *getOrCreateType(DebugTypeInfo DbgTy,
                                 llvm::DIScope *Scope = nullptr) {
     // Is this an empty type?
@@ -2357,7 +2378,7 @@ createSpecializedStructOrClassType(NominalOrBoundGenericNominalType *Type,
     StringRef MangledName;
     llvm::MDString *UID = nullptr;
     if (canMangle(DbgTy.getType())) {
-      MangledName = getMangledName(DbgTy);
+      MangledName = getMangledName(DbgTy, /*RespectOriginallyDefinedIn=*/true);
       UID = llvm::MDString::get(IGM.getLLVMContext(), MangledName);
       if (llvm::Metadata *CachedTy = DIRefMap.lookup(UID)) {
         auto DITy = cast<llvm::DIType>(CachedTy);
@@ -2382,7 +2403,18 @@ createSpecializedStructOrClassType(NominalOrBoundGenericNominalType *Type,
       ClangDecl = AliasDecl->getClangDecl();
     } else if (auto *ND = DbgTy.getType()->getNominalOrBoundGenericNominal()) {
       TypeDecl = ND;
-      Context = ND->getParent();
+      // If this is an originally defined in type, we want to emit this type's scope 
+      // to be the ABI module.
+      if (auto Attribute =
+              ND->getAttrs().getAttribute<OriginallyDefinedInAttr>()) {
+        auto Identifier = IGM.getSILModule().getASTContext().getIdentifier(
+            Attribute->OriginalModuleName);
+        void *Key = (void *)Identifier.get();
+        Scope =
+            getOrCreateModule(Key, TheCU, Attribute->OriginalModuleName, {});
+      } else {
+        Context = ND->getParent();
+      }
       ClangDecl = ND->getClangDecl();
     } else if (auto BNO = dyn_cast<BuiltinType>(DbgTy.getType())) {
       Context = BNO->getASTContext().TheBuiltinModule;
@@ -2431,6 +2463,8 @@ createSpecializedStructOrClassType(NominalOrBoundGenericNominalType *Type,
       FwdDeclTypes.emplace_back(
           std::piecewise_construct, std::make_tuple(MangledName),
           std::make_tuple(static_cast<llvm::Metadata *>(FwdDecl)));
+
+      handleOriginallyDefinedIn(DbgTy, FwdDecl, MangledName, getFile(Scope));
       return FwdDecl;
     }
     llvm::DIType *DITy = createType(DbgTy, MangledName, Scope, getFile(Scope));
@@ -2459,6 +2493,7 @@ createSpecializedStructOrClassType(NominalOrBoundGenericNominalType *Type,
     // Store it in the cache.
     DITypeCache.insert({DbgTy.getType(), llvm::TrackingMDNodeRef(DITy)});
 
+    handleOriginallyDefinedIn(DbgTy, DITy, MangledName, getFile(Scope));
     return DITy;
   }
 };

test/DebugInfo/module_abi_name.swift

@@ -6,7 +6,7 @@ class SomeClass {}
 @available(macOS 10.13, *)
 @_originallyDefinedIn(module: "ThirdModule", OSX 10.12)
 class DefinedElsewhere {}
-// CHECK: DICompositeType(tag: DW_TAG_structure_type, name: "DefinedElsewhere",{{.*}}runtimeLang: DW_LANG_Swift, identifier: "$s7Goodbye16DefinedElsewhereCD")
+// CHECK: DICompositeType(tag: DW_TAG_structure_type, name: "DefinedElsewhere",{{.*}}runtimeLang: DW_LANG_Swift, identifier: "$s11ThirdModule16DefinedElsewhereCD")
 
 let v1 = SomeClass()
 let v2 = DefinedElsewhere()

test/DebugInfo/originally_defined_in.swift

@@ -7,8 +7,10 @@
      let i = 10
  }
 
- // CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "A",{{.*}}identifier: "$s21originally_defined_in1AVD",{{.*}}specification: ![[S1:[0-9]+]]
- // CHECK: [[S1]] = !DICompositeType(tag: DW_TAG_structure_type, name: "A", scope: ![[S2:[0-9]+]]
- // CHECK: [[S2]] = !DIModule({{.*}}name: "Other"
-
+// CHECK: ![[MOD:[0-9]+]] = !DIModule(scope: null, name: "originally_defined_in"
+//
+ // CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "A",{{.*}}scope: ![[S:[0-9]+]]{{.*}}identifier: "$s5Other1AVD"
+ // CHECK: [[S]] = !DIModule({{.*}}name: "Other"
+ 
+ // CHECK: !DIImportedEntity(tag: DW_TAG_imported_declaration, name: "$s5Other1AVD",{{.*}}scope: ![[MOD]]
 let a = A()