Swift: Use per-config module file locations in multi-config generators

Place `.swiftmodule` files a subdirectory named after the configuration.

Fixes: #25864
Fixes: #25997

- Swift/RunCMakeTest.cmake:
  - CMP0157-OLD was enabled for Xcode, where it works.
  - A test was added that verifies .swiftmodule's are generated into
    separate directories with multi-config generators.

- Tests/SwiftOnly/CMakeLists.txt: tests were added that validate that
  cross-subdirectory module dependencies (via target_link_libraries)
  work.

1 files changed, 2 insertions, 15 deletions

diff --git a/Source/cmNinjaNormalTargetGenerator.cxx b/Source/cmNinjaNormalTargetGenerator.cxx
index fefe3a1..77c3e6a 100644
--- a/Source/cmNinjaNormalTargetGenerator.cxx
+++ b/Source/cmNinjaNormalTargetGenerator.cxx
@@ -1078,19 +1078,6 @@ void cmNinjaNormalTargetGenerator::WriteNvidiaDeviceLinkStatement(
   this->WriteNvidiaDeviceLinkRule(usedResponseFile, config);
 }
 
-/// Compute the swift module path for the target, sans any config-specific
-/// subdirectory.
-/// The returned path will need to be converted to the generator path
-static std::string GetSwiftModulePathTree(cmGeneratorTarget const* target)
-{
-  std::string moduleName = target->GetSwiftModuleName();
-  std::string moduleDirectory = target->GetPropertyOrDefault(
-    "Swift_MODULE_DIRECTORY",
-    target->LocalGenerator->GetCurrentBinaryDirectory());
-  std::string moduleFileName = target->GetSwiftModuleFileName();
-  return moduleDirectory + "/" + moduleFileName;
-}
-
 void cmNinjaNormalTargetGenerator::WriteLinkStatement(
   const std::string& config, const std::string& fileConfig,
   bool firstForConfig)
@@ -1205,7 +1192,7 @@ void cmNinjaNormalTargetGenerator::WriteLinkStatement(
 
     vars["SWIFT_MODULE_NAME"] = gt->GetSwiftModuleName();
     vars["SWIFT_MODULE"] = this->GetLocalGenerator()->ConvertToOutputFormat(
-      this->ConvertToNinjaPath(GetSwiftModulePathTree(gt)),
+      this->ConvertToNinjaPath(gt->GetSwiftModulePath(config)),
       cmOutputConverter::SHELL);
 
     vars["SWIFT_SOURCES"] = [this, config]() -> std::string {
@@ -1538,7 +1525,7 @@ void cmNinjaNormalTargetGenerator::WriteLinkStatement(
         if (dependency.Target &&
             dependency.Target->GetLinkerLanguage(config) == "Swift") {
           std::string swiftmodule = this->ConvertToNinjaPath(
-            GetSwiftModulePathTree(dependency.Target));
+            dependency.Target->GetSwiftModulePath(config));
           linkBuild.ImplicitDeps.emplace_back(swiftmodule);
         }
       }