Reland "[CMake] Bumps minimum version to 3.20.0.

This reverts commit d763c6e5e2. Adds the patch by @hans from https://github.com/llvm/llvm-project/issues/62719 This patch fixes the Windows build. d763c6e5e2 reverted the reviews D144509 [CMake] Bumps minimum version to 3.20.0. This partly undoes D137724. This change has been discussed on discourse https://discourse.llvm.org/t/rfc-upgrading-llvms-minimum-required-cmake-version/66193 Note this does not remove work-arounds for older CMake versions, that will be done in followup patches. D150532 [OpenMP] Compile assembly files as ASM, not C Since CMake 3.20, CMake explicitly passes "-x c" (or equivalent) when compiling a file which has been set as having the language C. This behaviour change only takes place if "cmake_minimum_required" is set to 3.20 or newer, or if the policy CMP0119 is set to new. Attempting to compile assembly files with "-x c" fails, however this is workarounded in many cases, as OpenMP overrides this with "-x assembler-with-cpp", however this is only added for non-Windows targets. Thus, after increasing cmake_minimum_required to 3.20, this breaks compiling the GNU assembly for Windows targets; the GNU assembly is used for ARM and AArch64 Windows targets when building with Clang. This patch unbreaks that. D150688 [cmake] Set CMP0091 to fix Windows builds after the cmake_minimum_required bump The build uses other mechanism to select the runtime. Fixes #62719 Reviewed By: #libc, Mordante Differential Revision: https://reviews.llvm.org/D151344
2024-11-23 05:40:09 +00:00 · 2023-05-24 18:12:32 +02:00 · 2023-05-24 18:12:32 +02:00 · cbaa3597aa
commit cbaa3597aa
parent a218c99181
38 changed files with 58 additions and 143 deletions
--- a/bolt/runtime/CMakeLists.txt
+++ b/bolt/runtime/CMakeLists.txt
@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 include(CheckIncludeFiles)
 include(GNUInstallDirs)

--- a/clang/CMakeLists.txt
+++ b/clang/CMakeLists.txt
@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)

 if(NOT DEFINED LLVM_COMMON_CMAKE_UTILS)
  set(LLVM_COMMON_CMAKE_UTILS ${CMAKE_CURRENT_SOURCE_DIR}/../cmake)
@ -11,13 +11,6 @@ include(${LLVM_COMMON_CMAKE_UTILS}/Modules/CMakePolicy.cmake
 if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
  project(Clang)
  set(CLANG_BUILT_STANDALONE TRUE)
-  if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-    message(WARNING
-      "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-      "minimum version of CMake required to build LLVM will become 3.20.0, and "
-      "using an older CMake will become an error. Please upgrade your CMake to "
-      "at least 3.20.0 now to avoid issues in the future!")
-  endif()
 endif()

 # Must go below project(..)
--- a/clang/tools/scan-build-py/tests/functional/exec/CMakeLists.txt
+++ b/clang/tools/scan-build-py/tests/functional/exec/CMakeLists.txt
@ -1,6 +1,6 @@
 project(exec C)

-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)

 include(CheckCCompilerFlag)
 check_c_compiler_flag("-std=c99" C99_SUPPORTED)
--- a/cmake/Modules/CMakePolicy.cmake
+++ b/cmake/Modules/CMakePolicy.cmake
@ -1,5 +1,10 @@
 # CMake policy settings shared between LLVM projects

+# CMP0091: MSVC runtime library flags are selected by an abstraction.
+# New in CMake 3.15. https://cmake.org/cmake/help/latest/policy/CMP0091.html
+if(POLICY CMP0091)
+  cmake_policy(SET CMP0091 OLD)
+endif()
 # 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)
--- a/compiler-rt/CMakeLists.txt
+++ b/compiler-rt/CMakeLists.txt
@ -3,24 +3,19 @@
 # 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)
+cmake_minimum_required(VERSION 3.20.0)
+
+set(LLVM_COMMON_CMAKE_UTILS "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")
+include(${LLVM_COMMON_CMAKE_UTILS}/Modules/CMakePolicy.cmake
+  NO_POLICY_SCOPE)

 # 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)
-  if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-    message(WARNING
-      "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-      "minimum version of CMake required to build LLVM will become 3.20.0, and "
-      "using an older CMake will become an error. Please upgrade your CMake to "
-      "at least 3.20.0 now to avoid issues in the future!")
-  endif()
 endif()

-set(LLVM_COMMON_CMAKE_UTILS "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")
-
 # Add path for custom compiler-rt modules.
 list(INSERT CMAKE_MODULE_PATH 0
  "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
--- a/compiler-rt/lib/builtins/CMakeLists.txt
+++ b/compiler-rt/lib/builtins/CMakeLists.txt
@ -3,14 +3,7 @@
 # architecture-specific code in various subdirectories.

 if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
-  cmake_minimum_required(VERSION 3.13.4)
-  if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-    message(WARNING
-      "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-      "minimum version of CMake required to build LLVM will become 3.20.0, and "
-      "using an older CMake will become an error. Please upgrade your CMake to "
-      "at least 3.20.0 now to avoid issues in the future!")
-  endif()
+  cmake_minimum_required(VERSION 3.20.0)

  set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)
  project(CompilerRTBuiltins C ASM)
--- a/compiler-rt/lib/crt/CMakeLists.txt
+++ b/compiler-rt/lib/crt/CMakeLists.txt
@ -1,12 +1,5 @@
 if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
-  cmake_minimum_required(VERSION 3.13.4)
-  if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-    message(WARNING
-      "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-      "minimum version of CMake required to build LLVM will become 3.20.0, and "
-      "using an older CMake will become an error. Please upgrade your CMake to "
-      "at least 3.20.0 now to avoid issues in the future!")
-  endif()
+  cmake_minimum_required(VERSION 3.20.0)

  set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)
  project(CompilerRTCRT C)
--- a/flang/CMakeLists.txt
+++ b/flang/CMakeLists.txt
@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)

 if(NOT DEFINED LLVM_COMMON_CMAKE_UTILS)
  set(LLVM_COMMON_CMAKE_UTILS ${CMAKE_CURRENT_SOURCE_DIR}/../cmake)
@ -39,13 +39,6 @@ if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
  message("Building Flang as a standalone project.")
  project(Flang)
  set(FLANG_STANDALONE_BUILD ON)
-  if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-    message(WARNING
-      "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-      "minimum version of CMake required to build LLVM will become 3.20.0, and "
-      "using an older CMake will become an error. Please upgrade your CMake to "
-      "at least 3.20.0 now to avoid issues in the future!")
-  endif()
 else()
  set(FLANG_STANDALONE_BUILD OFF)
 endif()
--- a/flang/lib/Decimal/CMakeLists.txt
+++ b/flang/lib/Decimal/CMakeLists.txt
@ -1,5 +1,5 @@
 if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
-  cmake_minimum_required(VERSION 3.13.4)
+  cmake_minimum_required(VERSION 3.20.0)

  project(FortranDecimal C CXX)

--- a/flang/runtime/CMakeLists.txt
+++ b/flang/runtime/CMakeLists.txt
@ -7,14 +7,7 @@
 #===------------------------------------------------------------------------===#

 if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
-  cmake_minimum_required(VERSION 3.13.4)
-  if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-    message(WARNING
-      "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-      "minimum version of CMake required to build LLVM will become 3.20.0, and "
-      "using an older CMake will become an error. Please upgrade your CMake to "
-      "at least 3.20.0 now to avoid issues in the future!")
-  endif()
+  cmake_minimum_required(VERSION 3.20.0)

  project(FlangRuntime C CXX)

--- a/libc/CMakeLists.txt
+++ b/libc/CMakeLists.txt
@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)

 # Include LLVM's cmake policies.
 if(NOT DEFINED LLVM_COMMON_CMAKE_UTILS)
--- a/libc/examples/hello_world/CMakeLists.txt
+++ b/libc/examples/hello_world/CMakeLists.txt
@ -1,5 +1,5 @@
 project(hello_world)
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 include(../examples.cmake)

 add_example(
--- a/libclc/CMakeLists.txt
+++ b/libclc/CMakeLists.txt
@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)

 project( libclc VERSION 0.2.0 LANGUAGES CXX C)

--- a/libcxx/CMakeLists.txt
+++ b/libcxx/CMakeLists.txt
@ -4,7 +4,7 @@
 #===============================================================================
 # Setup Project
 #===============================================================================
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)

 set(LLVM_COMMON_CMAKE_UTILS "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")

--- a/libcxxabi/CMakeLists.txt
+++ b/libcxxabi/CMakeLists.txt
@ -4,7 +4,7 @@
 # Setup Project
 #===============================================================================

-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)

 set(LLVM_COMMON_CMAKE_UTILS "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")

--- a/libunwind/CMakeLists.txt
+++ b/libunwind/CMakeLists.txt
@ -2,7 +2,7 @@
 # Setup Project
 #===============================================================================

-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)

 set(LLVM_COMMON_CMAKE_UTILS "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")

--- a/libunwind/src/CMakeLists.txt
+++ b/libunwind/src/CMakeLists.txt
@ -30,8 +30,7 @@ set(LIBUNWIND_ASM_SOURCES
 # CMake doesn't work correctly with assembly on AIX. Workaround by compiling
 # as C files as well.
 if((APPLE AND CMAKE_VERSION VERSION_LESS 3.19) OR
-   (MINGW AND CMAKE_VERSION VERSION_LESS 3.17) OR
-   (${CMAKE_SYSTEM_NAME} MATCHES "AIX"))
+   (MINGW AND CMAKE_VERSION VERSION_LESS 3.17))
  set_source_files_properties(${LIBUNWIND_ASM_SOURCES} PROPERTIES LANGUAGE C)
 endif()

--- a/lld/CMakeLists.txt
+++ b/lld/CMakeLists.txt
@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)

 if(NOT DEFINED LLVM_COMMON_CMAKE_UTILS)
  set(LLVM_COMMON_CMAKE_UTILS ${CMAKE_CURRENT_SOURCE_DIR}/../cmake)
@ -11,13 +11,6 @@ include(${LLVM_COMMON_CMAKE_UTILS}/Modules/CMakePolicy.cmake
 if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
  project(lld)
  set(LLD_BUILT_STANDALONE TRUE)
-  if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-    message(WARNING
-      "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-      "minimum version of CMake required to build LLVM will become 3.20.0, and "
-      "using an older CMake will become an error. Please upgrade your CMake to "
-      "at least 3.20.0 now to avoid issues in the future!")
-  endif()
 endif()

 # Must go below project(..)
--- a/lldb/CMakeLists.txt
+++ b/lldb/CMakeLists.txt
@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)

 if(NOT DEFINED LLVM_COMMON_CMAKE_UTILS)
  set(LLVM_COMMON_CMAKE_UTILS ${CMAKE_CURRENT_SOURCE_DIR}/../cmake)
@ -19,13 +19,6 @@ if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
  project(lldb)
  set(LLDB_BUILT_STANDALONE TRUE)
  set(LLVM_INCLUDE_TESTS ON CACHE INTERNAL "")
-  if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-    message(WARNING
-      "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-      "minimum version of CMake required to build LLVM will become 3.20.0, and "
-      "using an older CMake will become an error. Please upgrade your CMake to "
-      "at least 3.20.0 now to avoid issues in the future!")
-  endif()
 endif()

 # Must go below project(..)
--- a/lldb/tools/debugserver/CMakeLists.txt
+++ b/lldb/tools/debugserver/CMakeLists.txt
@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)

 project(Debugserver LANGUAGES C CXX ASM-ATT)

@ -7,13 +7,6 @@ include(GNUInstallDirs)

 if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
  set(LLDB_BUILT_STANDALONE TRUE)
-  if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-    message(WARNING
-      "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-      "minimum version of CMake required to build LLVM will become 3.20.0, and "
-      "using an older CMake will become an error. Please upgrade your CMake to "
-      "at least 3.20.0 now to avoid issues in the future!")
-  endif()

  set(CMAKE_MODULE_PATH
    ${CMAKE_MODULE_PATH}
--- a/llvm-libgcc/CMakeLists.txt
+++ b/llvm-libgcc/CMakeLists.txt
@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)

 if (NOT IS_DIRECTORY "${CMAKE_CURRENT_LIST_DIR}/../libunwind")
  message(FATAL_ERROR "llvm-libgcc requires being built in a monorepo layout with libunwind available")
--- a/llvm/CMakeLists.txt
+++ b/llvm/CMakeLists.txt
@ -1,13 +1,6 @@
 # See docs/CMake.html for instructions about how to build LLVM with CMake.

-cmake_minimum_required(VERSION 3.13.4)
-if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-  message(WARNING
-    "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-    "minimum version of CMake required to build LLVM will become 3.20.0, and "
-    "using an older CMake will become an error. Please upgrade your CMake to "
-    "at least 3.20.0 now to avoid issues in the future!")
-endif()
+cmake_minimum_required(VERSION 3.20.0)

 set(LLVM_COMMON_CMAKE_UTILS ${CMAKE_CURRENT_SOURCE_DIR}/../cmake)
 include(${LLVM_COMMON_CMAKE_UTILS}/Modules/CMakePolicy.cmake
--- a/llvm/docs/CMake.rst
+++ b/llvm/docs/CMake.rst
@ -34,7 +34,7 @@ Quick start
 We use here the command-line, non-interactive CMake interface.

 #. `Download <http://www.cmake.org/cmake/resources/software.html>`_ and install
-   CMake. Version 3.13.4 is the minimum required.
+   CMake. Version 3.20.0 is the minimum required.

 #. Open a shell. Your development tools must be reachable from this shell
   through the PATH environment variable.
@ -911,7 +911,7 @@ and uses them to build a simple application ``simple-tool``.

 .. code-block:: cmake

-  cmake_minimum_required(VERSION 3.13.4)
+  cmake_minimum_required(VERSION 3.20.0)
  project(SimpleProject)

  find_package(LLVM REQUIRED CONFIG)
--- a/llvm/docs/GettingStarted.rst
+++ b/llvm/docs/GettingStarted.rst
@ -280,7 +280,7 @@ uses the package and provides other details.
 =========================================================== ============ ==========================================
 Package                                                     Version      Notes
 =========================================================== ============ ==========================================
-`CMake <http://cmake.org/>`__                               >=3.13.4     Makefile/workspace generator
+`CMake <http://cmake.org/>`__                               >=3.20.0     Makefile/workspace generator
 `GCC <http://gcc.gnu.org/>`_                                >=7.1.0      C/C++ compiler\ :sup:`1`
 `python <http://www.python.org/>`_                          >=3.6        Automated test suite\ :sup:`2`
 `zlib <http://zlib.net>`_                                   >=1.2.3.4    Compression library\ :sup:`3`
--- a/llvm/docs/ReleaseNotes.rst
+++ b/llvm/docs/ReleaseNotes.rst
@ -47,6 +47,11 @@ Non-comprehensive list of changes in this release
 Update on required toolchains to build LLVM
 -------------------------------------------

+With LLVM 17.x we raised the version requirement of CMake used to build LLVM.
+The new requirements are as follows:
+
+* CMake >= 3.20.0
+
 Changes to the LLVM IR
 ----------------------

--- a/mlir/CMakeLists.txt
+++ b/mlir/CMakeLists.txt
@ -1,5 +1,5 @@
 # MLIR project.
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)

 if(NOT DEFINED LLVM_COMMON_CMAKE_UTILS)
  set(LLVM_COMMON_CMAKE_UTILS ${CMAKE_CURRENT_SOURCE_DIR}/../cmake)
@ -11,13 +11,6 @@ include(${LLVM_COMMON_CMAKE_UTILS}/Modules/CMakePolicy.cmake
 if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
  project(mlir)
  set(MLIR_STANDALONE_BUILD TRUE)
-  if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-    message(WARNING
-      "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-      "minimum version of CMake required to build LLVM will become 3.20.0, and "
-      "using an older CMake will become an error. Please upgrade your CMake to "
-      "at least 3.20.0 now to avoid issues in the future!")
-  endif()
 endif()

 # Must go below project(..)
--- a/mlir/examples/standalone/CMakeLists.txt
+++ b/mlir/examples/standalone/CMakeLists.txt
@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 project(standalone-dialect LANGUAGES CXX C)

 set(CMAKE_BUILD_WITH_INSTALL_NAME_DIR ON)
--- a/openmp/CMakeLists.txt
+++ b/openmp/CMakeLists.txt
@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)

 set(LLVM_COMMON_CMAKE_UTILS ${CMAKE_CURRENT_SOURCE_DIR}/../cmake)

@ -11,14 +11,7 @@ list(INSERT CMAKE_MODULE_PATH 0
 # llvm/runtimes/ will set OPENMP_STANDALONE_BUILD.
 if (OPENMP_STANDALONE_BUILD OR "${CMAKE_SOURCE_DIR}" STREQUAL "${CMAKE_CURRENT_SOURCE_DIR}")
  set(OPENMP_STANDALONE_BUILD TRUE)
-  project(openmp C CXX)
-  if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-    message(WARNING
-      "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-      "minimum version of CMake required to build LLVM will become 3.20.0, and "
-      "using an older CMake will become an error. Please upgrade your CMake to "
-      "at least 3.20.0 now to avoid issues in the future!")
-  endif()
+  project(openmp C CXX ASM)
 endif()

 # Must go below project(..)
--- a/openmp/cmake/DetectTestCompiler/CMakeLists.txt
+++ b/openmp/cmake/DetectTestCompiler/CMakeLists.txt
@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)
 project(DetectTestCompiler C CXX)

 include(CheckCCompilerFlag)
--- a/openmp/docs/SupportAndFAQ.rst
+++ b/openmp/docs/SupportAndFAQ.rst
@ -307,7 +307,7 @@ require a few additions.

 .. code-block:: cmake

-  cmake_minimum_required(VERSION 3.13.4)
+  cmake_minimum_required(VERSION 3.20.0)
  project(offloadTest VERSION 1.0 LANGUAGES CXX)

  list(APPEND CMAKE_MODULE_PATH "${PATH_TO_OPENMP_INSTALL}/lib/cmake/openmp")
@ -318,7 +318,7 @@ require a few additions.
  target_link_libraries(offload PRIVATE OpenMPTarget::OpenMPTarget_NVPTX)
  target_sources(offload PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/src/Main.cpp)

-Using this module requires at least CMake version 3.13.4. Supported languages
+Using this module requires at least CMake version 3.20.0. Supported languages
 are C and C++ with Fortran support planned in the future. Compiler support is
 best for Clang but this module should work for other compiler vendors such as
 IBM, GNU.
--- a/openmp/libompd/src/CMakeLists.txt
+++ b/openmp/libompd/src/CMakeLists.txt
@ -9,7 +9,7 @@
 #

 project (libompd)
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)

 add_library (ompd SHARED TargetValue.cpp omp-debug.cpp omp-state.cpp omp-icv.cpp)

--- a/openmp/libomptarget/plugins/remote/src/CMakeLists.txt
+++ b/openmp/libomptarget/plugins/remote/src/CMakeLists.txt
@ -10,7 +10,7 @@
 #
 ##===----------------------------------------------------------------------===##

-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)

 # Define the suffix for the runtime messaging dumps.
 add_definitions(-DTARGET_NAME=RPC)
--- a/openmp/runtime/src/CMakeLists.txt
+++ b/openmp/runtime/src/CMakeLists.txt
@ -133,8 +133,6 @@ libomp_get_asmflags(LIBOMP_CONFIGURED_ASMFLAGS)
 # Set the compiler flags for each type of source
 set_source_files_properties(${LIBOMP_CXXFILES} PROPERTIES COMPILE_FLAGS "${LIBOMP_CONFIGURED_CXXFLAGS}")
 set_source_files_properties(${LIBOMP_ASMFILES} ${LIBOMP_GNUASMFILES} PROPERTIES COMPILE_FLAGS "${LIBOMP_CONFIGURED_ASMFLAGS}")
-# Let the compiler handle the GNU assembly files
-set_source_files_properties(${LIBOMP_GNUASMFILES} PROPERTIES LANGUAGE C)

 # Remove any cmake-automatic linking of the standard C++ library.
 # We neither need (nor want) the standard C++ library dependency even though we compile c++ files.
--- a/openmp/tools/Modules/FindOpenMPTarget.cmake
+++ b/openmp/tools/Modules/FindOpenMPTarget.cmake
@ -79,7 +79,7 @@ be used to override the standard flag searching for a given compiler.
 # TODO: Test more compilers

 cmake_policy(PUSH)
-cmake_policy(VERSION 3.13.4)
+cmake_policy(VERSION 3.20.0)

 find_package(OpenMP ${OpenMPTarget_FIND_VERSION} REQUIRED)

--- a/openmp/tools/Modules/README.rst
+++ b/openmp/tools/Modules/README.rst
@ -26,7 +26,7 @@ require a few additions.

 .. code-block:: cmake

-  cmake_minimum_required(VERSION 3.13.4)
+  cmake_minimum_required(VERSION 3.20.0)
  project(offloadTest VERSION 1.0 LANGUAGES CXX)

  list(APPEND CMAKE_MODULE_PATH "${PATH_TO_OPENMP_INSTALL}/lib/cmake/openmp")
@ -37,7 +37,7 @@ require a few additions.
  target_link_libraries(offload PRIVATE OpenMPTarget::OpenMPTarget_NVPTX)
  target_sources(offload PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/src/Main.cpp)

-Using this module requires at least CMake version 3.13.4. Supported languages
+Using this module requires at least CMake version 3.20.0. Supported languages
 are C and C++ with Fortran support planned in the future. If your application
 requires building for a specific device architecture you can set the
 ``OpenMPTarget_<device>_ARCH=<flag>`` variable. Compiler support is best for
--- a/polly/CMakeLists.txt
+++ b/polly/CMakeLists.txt
@ -1,14 +1,7 @@
 # Check if this is a in tree build.
 if (NOT DEFINED LLVM_MAIN_SRC_DIR)
  project(Polly)
-  cmake_minimum_required(VERSION 3.13.4)
-  if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-    message(WARNING
-      "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-      "minimum version of CMake required to build LLVM will become 3.20.0, and "
-      "using an older CMake will become an error. Please upgrade your CMake to "
-      "at least 3.20.0 now to avoid issues in the future!")
-  endif()
+  cmake_minimum_required(VERSION 3.20.0)
  set(POLLY_STANDALONE_BUILD TRUE)
 endif()

--- a/pstl/CMakeLists.txt
+++ b/pstl/CMakeLists.txt
@ -5,7 +5,7 @@
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 #
 #===----------------------------------------------------------------------===##
-cmake_minimum_required(VERSION 3.13.4)
+cmake_minimum_required(VERSION 3.20.0)

 set(PARALLELSTL_VERSION_FILE "${CMAKE_CURRENT_SOURCE_DIR}/include/pstl/internal/pstl_config.h")
 file(STRINGS "${PARALLELSTL_VERSION_FILE}" PARALLELSTL_VERSION_SOURCE REGEX "#define _PSTL_VERSION .*$")
--- a/runtimes/CMakeLists.txt
+++ b/runtimes/CMakeLists.txt
@ -1,16 +1,13 @@
 # This file handles building LLVM runtime sub-projects.
-cmake_minimum_required(VERSION 3.13.4)
-if ("${CMAKE_VERSION}" VERSION_LESS "3.20.0")
-  message(WARNING
-    "Your CMake version is ${CMAKE_VERSION}. Starting with LLVM 17.0.0, the "
-    "minimum version of CMake required to build LLVM will become 3.20.0, and "
-    "using an older CMake will become an error. Please upgrade your CMake to "
-    "at least 3.20.0 now to avoid issues in the future!")
-endif()
-project(Runtimes C CXX ASM)
+cmake_minimum_required(VERSION 3.20.0)

 # Add path for custom and the LLVM build's modules to the CMake module path.
 set(LLVM_COMMON_CMAKE_UTILS "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")
+include(${LLVM_COMMON_CMAKE_UTILS}/Modules/CMakePolicy.cmake
+  NO_POLICY_SCOPE)
+
+project(Runtimes C CXX ASM)
+
 list(INSERT CMAKE_MODULE_PATH 0
  "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
  "${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules"