Revert "Harmonize cmake_policy() across standalone builds of all projects"

mgorny · mgorny · commit 687e5bccf890 · 2022-10-27T14:30:44.000+02:00
This reverts commit 88d7508. It's reported to break builds when symlinking other projects inside the `tools` directory.
diff --git a/clang/CMakeLists.txt b/clang/CMakeLists.txt
@@ -1,6 +1,4 @@
 cmake_minimum_required(VERSION 3.13.4)
-include(${CMAKE_CURRENT_SOURCE_DIR}/../cmake/Modules/CMakePolicy.cmake
-  NO_POLICY_SCOPE)
 
 # If we are not building as a part of LLVM, build Clang as an
 # standalone project, using LLVM as an external library:
diff --git a/cmake/Modules/CMakePolicy.cmake b/cmake/Modules/CMakePolicy.cmake
diff --git a/flang/CMakeLists.txt b/flang/CMakeLists.txt
@@ -1,6 +1,4 @@
 cmake_minimum_required(VERSION 3.13.4)
-include(${CMAKE_CURRENT_SOURCE_DIR}/../cmake/Modules/CMakePolicy.cmake
-  NO_POLICY_SCOPE)
 
 set(CMAKE_BUILD_WITH_INSTALL_NAME_DIR ON)
 
diff --git a/lld/CMakeLists.txt b/lld/CMakeLists.txt
@@ -1,6 +1,4 @@
 cmake_minimum_required(VERSION 3.13.4)
-include(${CMAKE_CURRENT_SOURCE_DIR}/../cmake/Modules/CMakePolicy.cmake
-  NO_POLICY_SCOPE)
 
 # If we are not building as a part of LLVM, build LLD as an
 # standalone project, using LLVM as an external library:
diff --git a/lldb/CMakeLists.txt b/lldb/CMakeLists.txt
@@ -1,6 +1,4 @@
 cmake_minimum_required(VERSION 3.13.4)
-include(${CMAKE_CURRENT_SOURCE_DIR}/../cmake/Modules/CMakePolicy.cmake
-  NO_POLICY_SCOPE)
 
 # Add path for custom modules.
 set(CMAKE_MODULE_PATH
diff --git a/lldb/cmake/modules/LLDBStandalone.cmake b/lldb/cmake/modules/LLDBStandalone.cmake
@@ -1,3 +1,9 @@
+# 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()
diff --git a/llvm/CMakeLists.txt b/llvm/CMakeLists.txt
@@ -1,8 +1,17 @@
 # See docs/CMake.html for instructions about how to build LLVM with CMake.
 
 cmake_minimum_required(VERSION 3.13.4)
-include(${CMAKE_CURRENT_SOURCE_DIR}/../cmake/Modules/CMakePolicy.cmake
-  NO_POLICY_SCOPE)
+
+# CMP0114: ExternalProject step targets fully adopt their steps.
+# New in CMake 3.19: https://cmake.org/cmake/help/latest/policy/CMP0114.html
+if(POLICY CMP0114)
+  cmake_policy(SET CMP0114 OLD)
+endif()
+# 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()
 
 set(CMAKE_BUILD_WITH_INSTALL_NAME_DIR ON)
 
diff --git a/mlir/CMakeLists.txt b/mlir/CMakeLists.txt
@@ -1,7 +1,4 @@
 # MLIR project.
-cmake_minimum_required(VERSION 3.13.4)
-include(${CMAKE_CURRENT_SOURCE_DIR}/../cmake/Modules/CMakePolicy.cmake
-  NO_POLICY_SCOPE)
 
 # Check if MLIR is built as a standalone project.
 if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
@@ -13,6 +10,8 @@ endif()
 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)
