Index: clang/CMakeLists.txt
===================================================================
--- clang/CMakeLists.txt
+++ clang/CMakeLists.txt
@@ -3,6 +3,13 @@
 # If we are not building as a part of LLVM, build Clang as an
 # standalone project, using LLVM as an external library:
 if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
+  # Please keep policies in sync with llvm/CMakeLists.txt.
+  if(POLICY CMP0114)
+    cmake_policy(SET CMP0114 OLD)
+  endif()
+  if(POLICY CMP0116)
+    cmake_policy(SET CMP0116 OLD)
+  endif()
   project(Clang)
   set(CLANG_BUILT_STANDALONE TRUE)
 endif()
Index: flang/CMakeLists.txt
===================================================================
--- flang/CMakeLists.txt
+++ flang/CMakeLists.txt
@@ -1,5 +1,22 @@
 cmake_minimum_required(VERSION 3.13.4)
 
+# Check for a standalone build and configure as appropriate from
+# there.
+if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
+  # Please keep policies in sync with llvm/CMakeLists.txt.
+  if(POLICY CMP0114)
+    cmake_policy(SET CMP0114 OLD)
+  endif()
+  if(POLICY CMP0116)
+    cmake_policy(SET CMP0116 OLD)
+  endif()
+  message("Building Flang as a standalone project.")
+  project(Flang)
+  set(FLANG_STANDALONE_BUILD ON)
+else()
+  set(FLANG_STANDALONE_BUILD OFF)
+endif()
+
 set(CMAKE_BUILD_WITH_INSTALL_NAME_DIR ON)
 
 # Flang requires C++17.
@@ -19,16 +36,6 @@
 
 option(FLANG_ENABLE_WERROR "Fail and stop building flang if a warning is triggered." OFF)
 
-# Check for a standalone build and configure as appropriate from
-# there.
-if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
-  message("Building Flang as a standalone project.")
-  project(Flang)
-  set(FLANG_STANDALONE_BUILD ON)
-else()
-  set(FLANG_STANDALONE_BUILD OFF)
-endif()
-
 # Must go below project(..)
 include(GNUInstallDirs)
 
Index: lld/CMakeLists.txt
===================================================================
--- lld/CMakeLists.txt
+++ lld/CMakeLists.txt
@@ -3,6 +3,13 @@
 # If we are not building as a part of LLVM, build LLD as an
 # standalone project, using LLVM as an external library:
 if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
+  # Please keep policies in sync with llvm/CMakeLists.txt.
+  if(POLICY CMP0114)
+    cmake_policy(SET CMP0114 OLD)
+  endif()
+  if(POLICY CMP0116)
+    cmake_policy(SET CMP0116 OLD)
+  endif()
   project(lld)
   set(LLD_BUILT_STANDALONE TRUE)
 endif()
Index: lldb/CMakeLists.txt
===================================================================
--- lldb/CMakeLists.txt
+++ lldb/CMakeLists.txt
@@ -1,19 +1,26 @@
 cmake_minimum_required(VERSION 3.13.4)
 
-# Add path for custom modules.
-set(CMAKE_MODULE_PATH
-  ${CMAKE_MODULE_PATH}
-  "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
-  "${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules"
-  )
-
 # If we are not building as part of LLVM, build LLDB as a standalone project,
 # using LLVM as an external library.
 if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
+  # Please keep policies in sync with llvm/CMakeLists.txt.
+  if(POLICY CMP0114)
+    cmake_policy(SET CMP0114 OLD)
+  endif()
+  if(POLICY CMP0116)
+    cmake_policy(SET CMP0116 OLD)
+  endif()
   project(lldb)
   set(LLDB_BUILT_STANDALONE TRUE)
 endif()
 
+# Add path for custom modules.
+set(CMAKE_MODULE_PATH
+  ${CMAKE_MODULE_PATH}
+  "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
+  "${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules"
+  )
+
 # Must go below project(..)
 include(GNUInstallDirs)
 
Index: lldb/cmake/modules/LLDBStandalone.cmake
===================================================================
--- lldb/cmake/modules/LLDBStandalone.cmake
+++ lldb/cmake/modules/LLDBStandalone.cmake
@@ -1,9 +1,3 @@
-# CMP0116: Ninja generators transform `DEPFILE`s from `add_custom_command()`
-# New in CMake 3.20. https://cmake.org/cmake/help/latest/policy/CMP0116.html
-if(POLICY CMP0116)
-  cmake_policy(SET CMP0116 OLD)
-endif()
-
 if(NOT DEFINED LLVM_COMMON_CMAKE_UTILS)
   set(LLVM_COMMON_CMAKE_UTILS ${CMAKE_CURRENT_SOURCE_DIR}/../cmake)
 endif()
Index: mlir/CMakeLists.txt
===================================================================
--- mlir/CMakeLists.txt
+++ mlir/CMakeLists.txt
@@ -1,7 +1,16 @@
 # MLIR project.
 
+cmake_minimum_required(VERSION 3.13.4)
+
 # Check if MLIR is built as a standalone project.
 if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
+  # Please keep policies in sync with llvm/CMakeLists.txt.
+  if(POLICY CMP0114)
+    cmake_policy(SET CMP0114 OLD)
+  endif()
+  if(POLICY CMP0116)
+    cmake_policy(SET CMP0116 OLD)
+  endif()
   project(mlir)
   set(MLIR_STANDALONE_BUILD TRUE)
 endif()
@@ -10,8 +19,6 @@
 include(GNUInstallDirs)
 
 if(MLIR_STANDALONE_BUILD)
-  cmake_minimum_required(VERSION 3.13.4)
-
   find_package(LLVM CONFIG REQUIRED)
   set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${LLVM_CMAKE_DIR})
   include(HandleLLVMOptions)