Swift/Ninja: Add support for response files

Adding support for `CMAKE_NINJA_FORCE_RESPONSE_FILE` with Swift.

Issue: #25490
Fixes: #25563

Modules/CMakeSwiftInformation.cmake

@@ -56,6 +56,7 @@ set(CMAKE_Swift_LIBRARY_PATH_TERMINATOR "")
 set(CMAKE_Swift_LINK_LIBRARY_FLAG "-l")
 set(CMAKE_Swift_LINKER_WRAPPER_FLAG "-Xlinker" " ")
 set(CMAKE_Swift_RESPONSE_FILE_LINK_FLAG @)
+set(CMAKE_Swift_RESPONSE_FILE_FLAG @)
 
 set(CMAKE_Swift_LINKER_PREFERENCE 50)
 set(CMAKE_Swift_LINKER_PREFERENCE_PROPAGATES 1)

Source/cmNinjaNormalTargetGenerator.cxx

@@ -453,7 +453,8 @@ void cmNinjaNormalTargetGenerator::WriteLinkRule(bool useResponseFile,
     vars.Language = lang.c_str();
     vars.AIXExports = "$AIX_EXPORTS";
 
-    if (this->TargetLinkLanguage(config) == "Swift") {
+    if (!this->GetLocalGenerator()->IsSplitSwiftBuild() &&
+        this->TargetLinkLanguage(config) == "Swift") {
       vars.SwiftLibraryName = "$SWIFT_LIBRARY_NAME";
       vars.SwiftModule = "$SWIFT_MODULE";
       vars.SwiftModuleName = "$SWIFT_MODULE_NAME";
@@ -508,7 +509,8 @@ void cmNinjaNormalTargetGenerator::WriteLinkRule(bool useResponseFile,
         vars.LinkLibraries = "$LINK_PATH $LINK_LIBRARIES";
       }
 
-      if (this->TargetLinkLanguage(config) == "Swift") {
+      if (!this->GetLocalGenerator()->IsSplitSwiftBuild() &&
+          this->TargetLinkLanguage(config) == "Swift") {
         vars.SwiftSources = responseFlag.c_str();
       } else {
         vars.Objects = responseFlag.c_str();

Source/cmNinjaTargetGenerator.cxx

@@ -2017,6 +2017,7 @@ void cmNinjaTargetGenerator::WriteSwiftObjectBuildStatement(
   std::string const targetObjectFilename = this->ConvertToNinjaPath(cmStrCat(
     objectDir, '/', moduleName,
     this->GetGlobalGenerator()->GetLanguageOutputExtension(language)));
+  objBuild.RspFile = cmStrCat(targetObjectFilename, ".swift.rsp");
 
   if (isSingleOutput) {
     this->LocalGenerator->AppendFlags(vars["FLAGS"],
@@ -2076,7 +2077,8 @@ void cmNinjaTargetGenerator::WriteSwiftObjectBuildStatement(
 
   // Write object build
   this->GetGlobalGenerator()->WriteBuild(this->GetImplFileStream(fileConfig),
-                                         objBuild);
+                                         objBuild,
+                                         this->ForceResponseFile() ? -1 : 0);
 }
 
 void cmNinjaTargetGenerator::WriteTargetDependInfo(std::string const& lang,

Tests/RunCMake/Swift/ForceResponseFile-check-stdout.txt

@@ -0,0 +1,4 @@
+swiftc [^
+]* -c @CMakeFiles/L.dir/L.o.swift.rsp [^
+]*
+.*swiftc -emit-library -static -o libL.a @CMakeFiles/L.rsp.*

Tests/RunCMake/Swift/ForceResponseFile.cmake

@@ -0,0 +1,13 @@
+if(POLICY CMP0157)
+  cmake_policy(SET CMP0157 NEW)
+endif()
+
+if(NOT CMAKE_GENERATOR STREQUAL "Ninja")
+  message(SEND_ERROR "this test must use Ninja generator, found ${CMAKE_GENERATOR} ")
+endif()
+
+set(CMAKE_NINJA_FORCE_RESPONSE_FILE TRUE)
+
+enable_language(Swift)
+
+add_library(L STATIC L.swift)

Tests/RunCMake/Swift/RunCMakeTest.cmake

@@ -69,6 +69,13 @@ elseif(RunCMake_GENERATOR STREQUAL Ninja)
       run_cmake(CompileCommands)
       run_cmake_command(CompileCommands-check ${CMAKE_COMMAND} --build ${CompileCommands_TEST_BINARY_DIR})
     endblock()
+
+    block()
+      set(ForceResponseFile_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/ForceResponseFile-build)
+      run_cmake(ForceResponseFile)
+      # -v: verbose to capture executed commands -n: dry-run to avoid actually compiling
+      run_cmake_command(ForceResponseFile-check ${CMAKE_COMMAND} --build ${ForceResponseFile_TEST_BINARY_DIR} -- -vn)
+    endblock()
   endif()
 elseif(RunCMake_GENERATOR STREQUAL "Ninja Multi-Config")
   if(CMake_TEST_Swift)