[cxx-interop] Enable reference-counted types on Windows

This enables the use of reference-counted foreign reference types on Windows. As it turns out, the assertion that was failing on Windows previously was unnecessary. This also enabled many of the tests on Windows.

rdar://154694125 / resolves swiftlang#82643

Author: egorzhdan

lib/IRGen/GenMeta.cpp

@@ -6880,7 +6880,7 @@ namespace {
 
     void emitInitializeMetadata(IRGenFunction &IGF, llvm::Value *metadata,
                                 MetadataDependencyCollector *collector) {
-      llvm_unreachable("Not implemented for foreign reference types.");
+      // Foreign reference types do not currently require extra metadata.
     }
 
     // Visitor methods.

test/Interop/C/struct/foreign-reference.swift

@@ -3,9 +3,6 @@
 //
 // REQUIRES: executable_test
 
-// XFAIL: OS=windows-msvc
-// FIXME: Runtime support for C++ foreign reference types is missing on Windows (https://github.com/swiftlang/swift/issues/82643)
-
 import StdlibUnittest
 import ForeignReference
 

test/Interop/Cxx/foreign-reference/array-of-classes.swift

@@ -8,9 +8,6 @@
 // REQUIRES: executable_test
 // UNSUPPORTED: back_deployment_runtime
 
-// Metadata for foreign reference types is not supported on Windows.
-// UNSUPPORTED: OS=windows-msvc
-
 //--- Inputs/module.modulemap
 
 module Test {

test/Interop/Cxx/foreign-reference/extensions.swift

@@ -1,9 +1,6 @@
 // RUN: %target-run-simple-swift(-I %S/Inputs/ -Xfrontend -cxx-interoperability-mode=default -Xfrontend -disable-availability-checking -Onone) | %FileCheck %s
 // REQUIRES: executable_test
 
-// Metadata for foreign reference types is not supported on Windows.
-// UNSUPPORTED: OS=windows-msvc
-
 import ReferenceCounted
 
 protocol MyProto {

test/Interop/Cxx/foreign-reference/inheritance.swift

@@ -1,9 +1,6 @@
 // REQUIRES: executable_test
 // RUN: %target-run-simple-swift(-cxx-interoperability-mode=default -Xfrontend -disable-availability-checking -I %S/Inputs)
 
-// TODO: Fix this lit test failure on windows rdar://145218056
-// XFAIL: OS=windows-msvc
-
 import Inheritance
 import StdlibUnittest
 

test/Interop/Cxx/foreign-reference/multiple-protocol-conformances.swift

@@ -2,8 +2,6 @@
 // RUN: split-file %s %t
 // RUN: %target-build-swift -I %S/Inputs %t/main.swift %t/second.swift -cxx-interoperability-mode=default -Xfrontend -disable-availability-checking
 
-// XFAIL: OS=windows-msvc
-
 //--- main.swift
 import ReferenceCounted
 

test/Interop/Cxx/foreign-reference/print-reference.swift

@@ -2,9 +2,6 @@
 
 // REQUIRES: executable_test
 
-// Metadata for foreign reference types is not supported on Windows.
-// UNSUPPORTED: OS=windows-msvc
-
 // Temporarily disable when running with an older runtime (rdar://153205860)
 // UNSUPPORTED: use_os_stdlib
 // UNSUPPORTED: back_deployment_runtime

test/Interop/Cxx/foreign-reference/reference-counted-irgen.swift

@@ -1,5 +1,4 @@
 // RUN: %target-swift-emit-irgen %s -I %S/Inputs -cxx-interoperability-mode=default -Xcc -fignore-exceptions -disable-availability-checking | %FileCheck %s
-// XFAIL: OS=windows-msvc
 
 import ReferenceCounted
 

test/Interop/Cxx/foreign-reference/reference-counted.swift

@@ -2,7 +2,6 @@
 // RUN: %target-run-simple-swift(-I %S/Inputs/ -Xfrontend -enable-experimental-cxx-interop -Xfrontend -validate-tbd-against-ir=none -Xfrontend -disable-llvm-verify -Xfrontend -disable-availability-checking -O)
 //
 // REQUIRES: executable_test
-// XFAIL: OS=windows-msvc
 
 // Temporarily disable when running with an older runtime (rdar://128681137)
 // UNSUPPORTED: use_os_stdlib

test/Interop/Cxx/foreign-reference/witness-table.swift

@@ -1,7 +1,6 @@
 // RUN: %target-run-simple-swift(-I %S/Inputs/ -Xfrontend -enable-experimental-cxx-interop -Xfrontend -validate-tbd-against-ir=none -Xfrontend -disable-llvm-verify -g)
 //
 // REQUIRES: executable_test
-// XFAIL: OS=windows-msvc
 
 // Temporarily disable when running with an older runtime (rdar://128681577)
 // UNSUPPORTED: use_os_stdlib