[CMake] Remove dead code setting policies to NEW

[tambre]

Summary

cmake_minimum_required(VERSION) calls cmake_policy(VERSION),
which sets all policies up to VERSION to NEW.
LLVM started requiring CMake 3.13 last year, so we can remove
a bunch of code setting policies prior to 3.13 to NEW as it
no longer has any effect.

[JDevlieghere]

LGTM for LLDB

[phosek]

LGTM

[tambre]

ldionne: for libc++ review

[ldionne]

Except for the google-benchmark nit, LGTM. Thanks a lot for the cleanup!

libcxx/utils/google-benchmark/CMakeLists.txt

3

I don't think we want to change this. It's a third-party project (which is inconveniently checked-in as-is into our tree..).

[tambre]

Don't modify third-party checked-in libraries.

[tambre]

libcxx/utils/google-benchmark/CMakeLists.txt

3

Good catch. Did the same for llvm/utils/benchmark/CMakeLists.txt, though that one seems to have the cmake_minimum_required(VERSION) updated to 3.13.4 unlike this one.

[tambre]

ldionne: ping

[ldionne]

Thanks!

clang/CMakeLists.txt

 cmake_minimum_required(VERSION 3.13.4)
 
-if(POLICY CMP0075)
-  cmake_policy(SET CMP0075 NEW)
-endif()
-
 # 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 )
   project(Clang)
 
   set(CMAKE_CXX_STANDARD 14 CACHE STRING "C++ standard to conform to")
   set(CMAKE_CXX_STANDARD_REQUIRED YES)
   set(CMAKE_CXX_EXTENSIONS NO)

compiler-rt/CMakeLists.txt

 # CMake build for CompilerRT.
 #
 # An important constraint of the build is that it only produces libraries
 # based on the ability of the host toolchain to target various platforms.
 
 cmake_minimum_required(VERSION 3.13.4)
 
-if(POLICY CMP0075)
-  cmake_policy(SET CMP0075 NEW)
-endif()
-
 # Check if compiler-rt is built as a standalone project.
 if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR OR COMPILER_RT_STANDALONE_BUILD)
   project(CompilerRT C CXX ASM)
   set(COMPILER_RT_STANDALONE_BUILD TRUE)
   set_property(GLOBAL PROPERTY USE_FOLDERS ON)
 endif()
 
 # Add path for custom compiler-rt modules.

flang/CMakeLists.txt

 cmake_minimum_required(VERSION 3.13.4)
 
-# RPATH settings on macOS do not affect INSTALL_NAME.
-if (POLICY CMP0068)
-  cmake_policy(SET CMP0068 NEW)
-  set(CMAKE_BUILD_WITH_INSTALL_NAME_DIR ON)
-endif()
-
-# Include file check macros honor CMAKE_REQUIRED_LIBRARIES.
-if(POLICY CMP0075)
-  cmake_policy(SET CMP0075 NEW)
-endif()
-
-# option() honors normal variables.
-if (POLICY CMP0077)
-  cmake_policy(SET CMP0077 NEW)
-endif()
 
 option(LINK_WITH_FIR "Link driver with FIR and LLVM" ON)
 option(FLANG_BUILD_NEW_DRIVER "Build the flang compiler driver" OFF)
 
 # Flang requires C++17.
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED TRUE)
 set(CMAKE_CXX_EXTENSIONS OFF)

libcxx/CMakeLists.txt

 # See https://libcxx.llvm.org/docs/BuildingLibcxx.html for instructions on how
 # to build libcxx with CMake.
 
 if (NOT IS_DIRECTORY "${CMAKE_CURRENT_LIST_DIR}/../libcxxabi")
   message(FATAL_ERROR "libc++ now requires being built in a monorepo layout with libcxxabi available")
 endif()
 
 #===============================================================================
 # Setup Project
 #===============================================================================
 cmake_minimum_required(VERSION 3.13.4)
 
-if(POLICY CMP0042)
-  cmake_policy(SET CMP0042 NEW) # Set MACOSX_RPATH=YES by default
-endif()
-if(POLICY CMP0022)
-  cmake_policy(SET CMP0022 NEW) # Required when interacting with LLVM and Clang
-endif()
-if(POLICY CMP0068)
-  cmake_policy(SET CMP0068 NEW)
-  set(CMAKE_BUILD_WITH_INSTALL_NAME_DIR ON)
-endif()
 
 # Add path for custom modules
 set(CMAKE_MODULE_PATH
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules"
   ${CMAKE_MODULE_PATH}
   )
 

libcxx/utils/ci/runtimes/CMakeLists.txt

 cmake_minimum_required(VERSION 3.13.4)
+project(LLVM_RUNTIMES)
 
-if(POLICY CMP0068)
-  cmake_policy(SET CMP0068 NEW)
-  set(CMAKE_BUILD_WITH_INSTALL_NAME_DIR ON)
-endif()
-
-if(POLICY CMP0075)
-  cmake_policy(SET CMP0075 NEW)
-endif()
-
-if(POLICY CMP0077)
-  cmake_policy(SET CMP0077 NEW)
-endif()
-
-project(LLVM_RUNTIMES)
 
 find_package(Python3 COMPONENTS Interpreter)
 if(NOT Python3_Interpreter_FOUND)
   message(WARNING "Python3 not found, using python2 as a fallback")
   find_package(Python2 COMPONENTS Interpreter REQUIRED)
   if(Python2_VERSION VERSION_LESS 2.7)
     message(SEND_ERROR "Python 2.7 or newer is required")
   endif()

libcxx/utils/google-benchmark/CMakeLists.txt

 cmake_minimum_required (VERSION 2.8.12)
-
-project (benchmark)
+project(benchmark)
 
-foreach(p
-    CMP0054 # CMake 3.1
-    CMP0056 # export EXE_LINKER_FLAGS to try_run
-    CMP0057 # Support no if() IN_LIST operator
-    )
-  if(POLICY ${p})
-    cmake_policy(SET ${p} NEW)
-  endif()
-endforeach()
-
 option(BENCHMARK_ENABLE_TESTING "Enable testing of the benchmark library." ON)
 option(BENCHMARK_ENABLE_EXCEPTIONS "Enable the use of exceptions in the benchmark library." ON)
 option(BENCHMARK_ENABLE_LTO "Enable link time optimisation of the benchmark library." OFF)
 option(BENCHMARK_USE_LIBCXX "Build and test using libc++ as the standard library." OFF)
 if(NOT MSVC)
   option(BENCHMARK_BUILD_32_BITS "Build a 32 bit version of the library." OFF)
 else()
   set(BENCHMARK_BUILD_32_BITS OFF CACHE BOOL "Build a 32 bit version of the library - unsupported when using MSVC)" FORCE)

libcxxabi/CMakeLists.txt

 # See www/CMake.html for instructions on how to build libcxxabi with CMake.
 
 if (NOT IS_DIRECTORY "${CMAKE_CURRENT_LIST_DIR}/../libcxx")
   message(FATAL_ERROR "libc++abi now requires being built in a monorepo layout with libcxx available")
 endif()
 
 #===============================================================================
 # Setup Project
 #===============================================================================
 
 cmake_minimum_required(VERSION 3.13.4)
 
-if(POLICY CMP0042)
-  cmake_policy(SET CMP0042 NEW) # Set MACOSX_RPATH=YES by default
-endif()
-
 # Add path for custom modules
 set(CMAKE_MODULE_PATH
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules"
   ${CMAKE_MODULE_PATH}
   )
 
 set(LIBCXXABI_SOURCE_DIR  ${CMAKE_CURRENT_SOURCE_DIR})

libunwind/CMakeLists.txt

 if (NOT IS_DIRECTORY "${CMAKE_CURRENT_LIST_DIR}/../libcxx")
   message(FATAL_ERROR "libunwind requires being built in a monorepo layout with libcxx available")
 endif()
 
 #===============================================================================
 # Setup Project
 #===============================================================================
 
 cmake_minimum_required(VERSION 3.13.4)
 
-if (POLICY CMP0042)
-  cmake_policy(SET CMP0042 NEW) # Set MACOSX_RPATH=YES by default
-endif()
-
 # Add path for custom modules
 set(CMAKE_MODULE_PATH
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules"
   ${CMAKE_MODULE_PATH}
   )
 
 set(LIBUNWIND_SOURCE_DIR  ${CMAKE_CURRENT_SOURCE_DIR})

lldb/CMakeLists.txt

 cmake_minimum_required(VERSION 3.13.4)
 
-if(POLICY CMP0075)
-  cmake_policy(SET CMP0075 NEW)
-endif()
-
-if(POLICY CMP0077)
-  cmake_policy(SET CMP0077 NEW)
-endif()
-
 # 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,

llvm/CMakeLists.txt

 # See docs/CMake.html for instructions about how to build LLVM with CMake.
 
 cmake_minimum_required(VERSION 3.13.4)
 
-if(POLICY CMP0068)
-  cmake_policy(SET CMP0068 NEW)
-  set(CMAKE_BUILD_WITH_INSTALL_NAME_DIR ON)
-endif()
-
-if(POLICY CMP0075)
-  cmake_policy(SET CMP0075 NEW)
-endif()
-
-if(POLICY CMP0077)
-  cmake_policy(SET CMP0077 NEW)
-endif()
 
 if(NOT DEFINED LLVM_VERSION_MAJOR)
   set(LLVM_VERSION_MAJOR 12)
 endif()
 if(NOT DEFINED LLVM_VERSION_MINOR)
   set(LLVM_VERSION_MINOR 0)
 endif()
 if(NOT DEFINED LLVM_VERSION_PATCH)

llvm/utils/benchmark/CMakeLists.txt

 cmake_minimum_required(VERSION 3.13.4)
-
-# Tell cmake 3.0+ that it's safe to clear the PROJECT_VERSION variable in the
-# call to project() below.
-if(POLICY CMP0048)
-  cmake_policy(SET CMP0048 NEW)
-endif()
-
-project (benchmark)
+project(benchmark)
 
-foreach(p
-    CMP0054 # CMake 3.1
-    CMP0056 # export EXE_LINKER_FLAGS to try_run
-    CMP0057 # Support no if() IN_LIST operator
-    )
-  if(POLICY ${p})
-    cmake_policy(SET ${p} NEW)
-  endif()
-endforeach()
-
 option(BENCHMARK_ENABLE_TESTING "Enable testing of the benchmark library." ON)
 option(BENCHMARK_ENABLE_EXCEPTIONS "Enable the use of exceptions in the benchmark library." ON)
 option(BENCHMARK_ENABLE_LTO "Enable link time optimisation of the benchmark library." OFF)
 option(BENCHMARK_USE_LIBCXX "Build and test using libc++ as the standard library." OFF)
 option(BENCHMARK_BUILD_32_BITS "Build a 32 bit version of the library." OFF)
 option(BENCHMARK_ENABLE_INSTALL "Enable installation of benchmark. (Projects embedding benchmark may want to turn this OFF.)" ON)
 
 # Allow unmet dependencies to be met using CMake's ExternalProject mechanics, which

mlir/examples/standalone/CMakeLists.txt

 cmake_minimum_required(VERSION 3.13.4)
+project(standalone-dialect LANGUAGES CXX C)
 
-if(POLICY CMP0068)
-  cmake_policy(SET CMP0068 NEW)
-  set(CMAKE_BUILD_WITH_INSTALL_NAME_DIR ON)
-endif()
-
-if(POLICY CMP0075)
-  cmake_policy(SET CMP0075 NEW)
-endif()
-
-if(POLICY CMP0077)
-  cmake_policy(SET CMP0077 NEW)
-endif()
-
-project(standalone-dialect LANGUAGES CXX C)
 
 set(CMAKE_CXX_STANDARD 14 CACHE STRING "C++ standard to conform to")
 
 find_package(MLIR REQUIRED CONFIG)
 
 message(STATUS "Using MLIRConfig.cmake in: ${MLIR_DIR}")
 message(STATUS "Using LLVMConfig.cmake in: ${LLVM_DIR}")