From 32d941e75cd1856813d5c5b116fbb01c54d5629f Mon Sep 17 00:00:00 2001
From: Rintaro Ishizaki <rishizaki@apple.com>
Date: Mon, 16 Oct 2023 13:50:05 -0700
Subject: [PATCH] [CMake] Remove set(CACHE) line for
 SWIFT_MODULE_ABI_NAME_PREFIX

Due to https://cmake.org/cmake/help/latest/policy/CMP0126.html
set(CACHE) overwrites the existing value if the cache has not been set
to any value. Since we don't need any default value, just remove it.

(cherry picked from commit d8c86952281b50012766e0bcbf201c2ad16278ed)
---
 CMakeLists.txt                          | 2 --
 cmake/modules/AddSwiftHostLibrary.cmake | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 928f3a2b8a6..9b2cf7ad094 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -22,8 +22,6 @@ if(CMAKE_VERSION VERSION_LESS 3.21)
   endif()
 endif()
 
-set(SWIFT_MODULE_ABI_NAME_PREFIX CACHE STRING "ABI name prefix to avoid name conflicts")
-
 # The subdirectory into which host libraries will be installed.
 set(SWIFT_HOST_LIBRARIES_SUBDIRECTORY "swift/host")
 
diff --git a/cmake/modules/AddSwiftHostLibrary.cmake b/cmake/modules/AddSwiftHostLibrary.cmake
index e8e6e4c717b..f1158ab394a 100644
--- a/cmake/modules/AddSwiftHostLibrary.cmake
+++ b/cmake/modules/AddSwiftHostLibrary.cmake
@@ -79,6 +79,7 @@ function(add_swift_syntax_library name)
       -emit-module-interface-path;${module_interface_file}
     >)
   if(SWIFT_MODULE_ABI_NAME_PREFIX)
+    # ABI name prefix. this can be used to avoid name conflicts.
     target_compile_options("${name}" PRIVATE
       $<$<COMPILE_LANGUAGE:Swift>:
         "SHELL:-Xfrontend -module-abi-name"