Merge pull request #58957 from johnno1962/bootstrap-fix

Potential fix for --xcode build on M1.

SwiftCompilerSources/CMakeLists.txt

@@ -171,19 +171,16 @@ function(add_swift_compiler_modules_library name)
   endforeach()
 
   # Create a static library containing all module object files.
+  if (XCODE)
+    # Xcode does not compile libraries that contain only object files.
+    # Therefore, it fails to create the static library. As a workaround,
+    # we add an empty source file force_lib.c to the target.
+    set(all_obj_files force_lib.c ${all_obj_files})
+  endif()
   add_library(${name} STATIC ${all_obj_files})
   add_dependencies(${name} ${all_module_targets})
   set_target_properties(${name} PROPERTIES LINKER_LANGUAGE CXX)
   set_property(GLOBAL APPEND PROPERTY SWIFT_BUILDTREE_EXPORTS ${name})
-
-  # Xcode does not compile libraries that contain only object files.
-  # Therefore, it fails to create the static library. As a workaround,
-  # we add a dummy script phase to the target.
-  if (XCODE)
-    add_custom_command(TARGET ${name} POST_BUILD 
-      COMMAND ""
-      COMMENT "Dummy script phase to force building this target")
-  endif()
 endfunction()
 
 

SwiftCompilerSources/force_lib.c

@@ -0,0 +1,15 @@
+//===--- force_lib.c ------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+/// Dummy source file to force CMake generated SwiftInTheCompiler.xcodeproj
+/// to sucessfully build static libraries conatining only object files used
+/// during "bootstrap" process to link Swift sources into the compiler.