[DebugInfo] Handle types with @_originallyDefinedIn in DebugInfo

lib/IRGen/IRGenDebugInfo.cpp

@@ -1792,6 +1792,28 @@ createSpecializedStructOrClassType(NominalOrBoundGenericNominalType *Type,
       return InternalType;
     }
 
+    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()) {
     case TypeKind::BuiltinUnboundGeneric:
@@ -1894,7 +1916,8 @@ createSpecializedStructOrClassType(NominalOrBoundGenericNominalType *Type,
             llvm::dwarf::DW_TAG_structure_type, MangledName, Scope, L.File,
             FwdDeclLine, llvm::dwarf::DW_LANG_Swift, 0, AlignInBits);
       return createOpaqueStruct(Scope, Name, L.File, FwdDeclLine, SizeInBits,
-                                AlignInBits, Flags, MangledName);
+                                AlignInBits, Flags, MangledName, {},
+                                SpecificationOf);
     }
 
     case TypeKind::Class: {
@@ -1931,7 +1954,8 @@ createSpecializedStructOrClassType(NominalOrBoundGenericNominalType *Type,
         return DIType;
       }
       return createPointerSizedStruct(Scope, Decl->getNameStr(), L.File,
-                                      FwdDeclLine, Flags, MangledName);
+                                      FwdDeclLine, Flags, MangledName,
+                                      SpecificationOf);
     }
 
     case TypeKind::Protocol: {
@@ -1977,11 +2001,11 @@ createSpecializedStructOrClassType(NominalOrBoundGenericNominalType *Type,
         return createSpecializedStructOrClassType(
             StructTy, Decl, Scope, L.File, L.Line, SizeInBits, AlignInBits,
             Flags, MangledName);
-      
+
       return createOpaqueStructWithSizedContainer(
           Scope, Decl ? Decl->getNameStr() : "", L.File, FwdDeclLine,
           SizeInBits, AlignInBits, Flags, MangledName,
-          collectGenericParams(StructTy));
+          collectGenericParams(StructTy), SpecificationOf);
     }
 
     case TypeKind::BoundGenericClass: {
@@ -1999,9 +2023,9 @@ createSpecializedStructOrClassType(NominalOrBoundGenericNominalType *Type,
       // attribute accordingly.
       assert(SizeInBits ==
              CI.getTargetInfo().getPointerWidth(clang::LangAS::Default));
-      return createPointerSizedStruct(Scope,
-                                      Decl ? Decl->getNameStr() : MangledName,
-                                      L.File, FwdDeclLine, Flags, MangledName);
+      return createPointerSizedStruct(
+          Scope, Decl ? Decl->getNameStr() : MangledName, L.File, FwdDeclLine,
+          Flags, MangledName, SpecificationOf);
     }
 
     case TypeKind::Pack:
@@ -2122,7 +2146,7 @@ createSpecializedStructOrClassType(NominalOrBoundGenericNominalType *Type,
       }
       return createOpaqueStruct(Scope, Decl->getName().str(), L.File,
                                 FwdDeclLine, SizeInBits, AlignInBits, Flags,
-                                MangledName);
+                                MangledName, {}, SpecificationOf);
     }
 
     case TypeKind::BoundGenericEnum: {
@@ -2142,7 +2166,8 @@ createSpecializedStructOrClassType(NominalOrBoundGenericNominalType *Type,
       }
       return createOpaqueStructWithSizedContainer(
           Scope, Decl->getName().str(), L.File, FwdDeclLine, SizeInBits,
-          AlignInBits, Flags, MangledName, collectGenericParams(EnumTy));
+          AlignInBits, Flags, MangledName, collectGenericParams(EnumTy),
+          SpecificationOf);
     }
 
     case TypeKind::BuiltinVector: {
@@ -2322,7 +2347,8 @@ createSpecializedStructOrClassType(NominalOrBoundGenericNominalType *Type,
     }
   }
 
-  llvm::DIType *getOrCreateType(DebugTypeInfo DbgTy) {
+  llvm::DIType *getOrCreateType(DebugTypeInfo DbgTy,
+                                llvm::DIScope *Scope = nullptr) {
     // Is this an empty type?
     if (DbgTy.isNull())
       // We can't use the empty type as an index into DenseMap.
@@ -2354,7 +2380,6 @@ createSpecializedStructOrClassType(NominalOrBoundGenericNominalType *Type,
     //
     // FIXME: Builtin and qualified types in LLVM have no parent
     // scope. TODO: This can be fixed by extending DIBuilder.
-    llvm::DIScope *Scope = nullptr;
     // Make sure to retrieve the context of the type alias, not the pointee.
     DeclContext *Context = nullptr;
     const Decl *TypeDecl = nullptr;

test/DebugInfo/originally_defined_in.swift

@@ -0,0 +1,14 @@
+// RUN: %target-swift-frontend -primary-file %s -emit-ir -g -o - | %FileCheck %s
+
+ @_originallyDefinedIn(
+      module: "Other", iOS 2.0, macOS 2.0, tvOS 2.0, watchOS 2.0)
+ @available(iOS 1.0, macOS 1.0, tvOS 1.0, watchOS 1.0, *)
+ public struct A {
+     let i = 10
+ }
+
+ // CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "A",{{.*}}identifier: "$s21originally_defined_in1AVD",{{.*}}specification_of: ![[S1:[0-9]+]]
+ // CHECK: [[S1]] = !DICompositeType(tag: DW_TAG_structure_type, name: "A", scope: ![[S2:[0-9]+]]
+ // CHECK: [[S2]] = !DIModule({{.*}}name: "Other"
+
+let a = A()