diff --git a/Source/cmGlobalXCodeGenerator.cxx b/Source/cmGlobalXCodeGenerator.cxx
index 5738799ee1..456f5bc73c 100644
--- a/Source/cmGlobalXCodeGenerator.cxx
+++ b/Source/cmGlobalXCodeGenerator.cxx
@@ -2423,6 +2423,18 @@ void cmGlobalXCodeGenerator::CreateBuildSettings(cmGeneratorTarget* gtgt,
   this->AppendDefines(ppDefs, targetDefines);
   buildSettings->AddAttribute("GCC_PREPROCESSOR_DEFINITIONS",
                               ppDefs.CreateList());
+  if (languages.count("Swift")) {
+    if (this->XcodeVersion < 80) {
+      std::string defineString;
+      std::set<std::string> defines(targetDefines.begin(),
+                                    targetDefines.end());
+      this->CurrentLocalGenerator->JoinDefines(defines, defineString, "Swift");
+      cflags["Swift"] += " " + defineString;
+    } else {
+      buildSettings->AddAttribute("SWIFT_ACTIVE_COMPILATION_CONDITIONS",
+                                  ppDefs.CreateList());
+    }
+  }
 
   std::string extraLinkOptionsVar;
   std::string extraLinkOptions;
diff --git a/Tests/SwiftOnly/CMakeLists.txt b/Tests/SwiftOnly/CMakeLists.txt
index 01c2222dc1..e92e544391 100644
--- a/Tests/SwiftOnly/CMakeLists.txt
+++ b/Tests/SwiftOnly/CMakeLists.txt
@@ -25,6 +25,7 @@ endif()
 set(CMAKE_Swift_MODULE_DIRECTORY ${CMAKE_BINARY_DIR}/swift)
 
 add_executable(SwiftOnly main.swift)
+target_compile_definitions(SwiftOnly PRIVATE SWIFTONLY)
 
 add_library(L L.swift)
 
diff --git a/Tests/SwiftOnly/main.swift b/Tests/SwiftOnly/main.swift
index 28560d076d..a3f1a2c1d4 100644
--- a/Tests/SwiftOnly/main.swift
+++ b/Tests/SwiftOnly/main.swift
@@ -1 +1,7 @@
 dump("SwiftOnly")
+
+#if SWIFTONLY
+dump("SWIFTONLY defined")
+#else
+fatalError("SWIFTONLY NOT defined")
+#endif