CMake 3.18.0-rc2 is ready for testing

Announcements
1

I am proud to announce the second CMake 3.18 release candidate.
https://cmake.org/download/

Documentation is available at:
https://cmake.org/cmake/help/v3.18

Release notes appear below and are also published at
https://cmake.org/cmake/help/v3.18/release/3.18.html

Some of the more significant changes in CMake 3.18 are:

  • The “CUDA” language can now be compiled using Clang on non-Windows
    platforms. Separable compilation is not yet supported on any
    platform. This is experimental and still under development.

  • “cmake(1)” gained support for profiling of CMake scripts through the
    parameters “–profiling-output” and “–profiling-format”.

  • The “add_library()” and “add_executable()” commands learned to
    create Alias Targets referencing non-“GLOBAL” Imported Targets.

  • The “cmake_language()” command was added for meta-operations on
    scripted or built-in commands, starting with a mode to “CALL” other
    commands, and “EVAL CODE” to inplace evaluate a CMake script.

  • The “file(CONFIGURE)” subcommand was created in order to replicate
    the “configure_file()” functionality without resorting to a pre-
    existing file on disk as input. The content is instead passed as a
    string.

  • The “find_program()”, “find_library()”, “find_path()” and
    “find_file()” commands gained a new “REQUIRED” option that will stop
    processing with an error message if nothing is found.

  • A “CMAKE_CUDA_ARCHITECTURES” variable was added to specify CUDA
    output architectures. Users are encouraged to use this instead of
    specifying options manually, as this approach is compiler-agnostic.
    The variable is initialized automatically when
    “CMAKE_CUDA_COMPILER_ID” is “NVIDIA”. The variable is used to
    initialize the new “CUDA_ARCHITECTURES” target property. See policy
    “CMP0104”.

  • The “UNITY_BUILD_MODE” target property was added to tell generators
    which algorithm (“BATCH”, “GROUP”) to use for grouping included source
    files.

  • The “CheckLinkerFlag” module has been added to provide a facility to
    check validity of link flags.

  • The “$<DEVICE_LINK:…>” and “$<HOST_LINK:…>” “generator
    expressions” were added to manage device and host link steps.

  • The “$<LINK_LANGUAGE:…>” and “$<LINK_LANG_AND_ID:…>” “generator
    expressions” were added.

  • “ctest(1)” gained a new “CTEST_RESOURCE_SPEC_FILE” variable, which
    can be used to specify a resource specification file.

  • “ccmake(1)” learned to read a “CCMAKE_COLORS” environment variable
    to customize colors.

  • On Windows, the “Ninja” and “Ninja Multi-Config” generators, when a
    compiler is not explicitly specified, now select the first compiler
    (of any name) found in directories listed by the “PATH” environment
    variable.

CMake 3.18 Release Notes

Changes made since CMake 3.17 include the following.

New Features

Languages

  • The “CUDA” language can now be compiled using Clang on non-Windows
    platforms. Separable compilation is not yet supported on any
    platform. This is experimental and still under development.

Command-Line

  • “cmake(1)” gained support for profiling of CMake scripts through the
    parameters “–profiling-output” and “–profiling-format”.

  • “cmake(1)” gained a “cat” command line option that can be used to
    concatenate files and print them on standard output.

Commands

  • The “add_library()” and “add_executable()” commands learned to
    create Alias Targets referencing non-“GLOBAL” Imported Targets.

  • The “cmake_language()” command was added for meta-operations on
    scripted or built-in commands, starting with a mode to “CALL” other
    commands, and “EVAL CODE” to inplace evaluate a CMake script.

  • The “execute_process()” command gained the “ECHO_OUTPUT_VARIABLE”
    and “ECHO_ERROR_VARIABLE” options.

  • The “export()” command now raise an error if used multiple times
    with same “FILE” without “APPEND”. See policy “CMP0103”.

  • The “file()” command gained the “ARCHIVE_CREATE” and
    “ARCHIVE_EXTRACT” subcommands to expose the “cmake(1)” “-E tar”
    functionality to CMake scripting code.

  • The “file(CONFIGURE)” subcommand was created in order to replicate
    the “configure_file()” functionality without resorting to a pre-
    existing file on disk as input. The content is instead passed as a
    string.

  • The “file(UPLOAD)” command gained “TLS_VERIFY” and “TLS_CAINFO”
    options to control server certificate verification.

  • The “find_program()”, “find_library()”, “find_path()” and
    “find_file()” commands gained a new “REQUIRED” option that will stop
    processing with an error message if nothing is found.

  • The “get_property()” command with “SOURCE” scope gained the
    “DIRECTORY” and “TARGET_DIRECTORY” options to get a property from
    the provided directory scope.

  • The “get_source_file_property()” command gained the “DIRECTORY” and
    “TARGET_DIRECTORY” options to get a property from the provided
    directory scope.

  • The “list()” operation “SORT” gained the “NATURAL” sort option to
    sort using natural order (see “strverscmp(3)” manual).

  • The “set_property()” command with the “SOURCE” scope gained the
    “DIRECTORY” and “TARGET_DIRECTORY” options to set properties in the
    provided directory scopes.

  • The “set_source_files_properties()” command gained the “DIRECTORY”
    and “TARGET_DIRECTORY” options to set properties in the provided
    directory scopes.

  • The “string()” command learned a new “HEX” sub-command, which
    converts strings into their hexadecimal representation.

Variables

  • A “CMAKE_CUDA_ARCHITECTURES” variable was added to specify CUDA
    output architectures. Users are encouraged to use this instead of
    specifying options manually, as this approach is compiler-agnostic.
    The variable is initialized automatically when
    “CMAKE_CUDA_COMPILER_ID” is “NVIDIA”. The variable is used to
    initialize the new “CUDA_ARCHITECTURES” target property. See policy
    “CMP0104”.

  • The “CMAKE_PCH_WARN_INVALID” variable was added to initialize the
    “PCH_WARN_INVALID” target property to allow the removal of the
    precompiled header invalid warning.

Properties

  • The “CUDA_ARCHITECTURES” target property was added to specify CUDA
    output architectures. Users are encouraged to use this instead of
    specifying options manually, as this approach is compiler-agnostic.
    The property is initialized by the new “CMAKE_CUDA_ARCHITECTURES”
    variable. See policy “CMP0104”.

  • The “Fortran_PREPROCESS” target property and “Fortran_PREPROCESS”
    source-file property were added to control preprocessing of Fortran
    source files.

  • The “FRAMEWORK_MULTI_CONFIG_POSTFIX_” target property and
    associated “CMAKE_FRAMEWORK_MULTI_CONFIG_POSTFIX_” variable
    were created to allow adding a postfix to the name of a framework
    file name when using a multi-config generator.

  • The “OBJECT_OUTPUTS” source file property now supports “generator
    expressions”.

  • The “UNITY_BUILD_MODE” target property was added to tell generators
    which algorithm to use for grouping included source files.

  • The “VS_SOURCE_SETTINGS_” target property was added to tell
    Visual Studio Generators for VS 2010 and above to add metadata to
    non-built source files using “”.

  • The “VS_SETTINGS” source file property was added to tell Visual
    Studio Generators for VS 2010 and above to add metadata to a non-
    built source file.

  • The “VS_PLATFORM_TOOLSET” target property was added to tell Visual
    Studio Generators for VS 2010 and above to override the platform
    toolset.

  • The “VS_SOLUTION_DEPLOY” target property was added to tell Visual
    Studio Generators for VS 2010 and above to mark a target for
    deployment even when not building for Windows Phone/Store/CE.

Modules

  • The “CheckLinkerFlag” module has been added to provide a facility to
    check validity of link flags.

  • The “ExternalProject” module “ExternalProject_Add()” command gained
    a new “GIT_REMOTE_UPDATE_STRATEGY” keyword. This can be used to
    specify how failed rebase operations during a git update should be
    handled. The “CMAKE_EP_GIT_REMOTE_UPDATE_STRATEGY” variable was also
    added as a global default and is honored by both the
    “ExternalProject” and “FetchContent” modules.

  • The “FetchContent” module “FetchContent_Declare()” command now
    supports a “SOURCE_SUBDIR” option. It can be used to direct
    “FetchContent_MakeAvailable()” to look in a different location for
    the “CMakeLists.txt” file.

  • The “FindBLAS” module now provides an imported target.

  • The “FindCUDAToolkit” module:

    • gained the variable “CUDAToolkit_LIBRARY_ROOT”, which is the
      directory containing the “nvvm” directory and “version.txt”.

    • uses toolkit and library root found during “CUDA” compiler
      detection.

  • The “FindLAPACK” module now provides an imported target.

  • The “FindPython3”, “FindPython2” and “FindPython” modules:

    • gained the possibility to create per-artifact cache variables for
      interactive editing in “cmake-gui(1)” and “ccmake(1)”.

    • gained sub-components “Development.Module” and “Development.Embed”
      under the “Development” component.

    • gained the capability to specify which Python implementations to
      find, including “IronPython” and “PyPy”.

  • The “FindRuby” module input and output variables were all renamed
    from “RUBY_” to “Ruby_” for consistency with other find modules.
    Input variables of the old case will be honored if provided, and
    output variables of the old case are always provided.

  • The “FindSWIG” module now accepts target languages as “COMPONENTS”
    and “OPTIONAL_COMPONENTS” arguments to “find_package”.

  • The “GoogleTest” module “gtest_discover_tests()” command:

    • gained a new “DISCOVERY_MODE” option to control when the test
      discovery step is run. It offers a new “PRE_TEST” setting to run
      the discovery at test time instead of build time.

    • gained a new optional parameter “XML_OUTPUT_DIR”. When set the
      JUnit XML test results are stored in that directory.

  • The “FindLibXslt” module now provides imported targets.

  • The “UseSWIG” module now supports Fortran as a target language if
    the “SWIG_EXECUTABLE” is SWIG-Fortran.

Generator Expressions

  • The “$<DEVICE_LINK:…>” and “$<HOST_LINK:…>” “generator
    expressions” were added to manage device and host link steps.

  • The “$<LINK_LANGUAGE:…>” and “$<LINK_LANG_AND_ID:…>” “generator
    expressions” were added.

CTest

  • “ctest(1)” gained a new “CTEST_RESOURCE_SPEC_FILE” variable, which
    can be used to specify a resource specification file.

  • “ctest(1)” gained a “–stop-on-failure” option, which can be used to
    stop running the tests once one has failed.

  • The “ctest_test()” command gained a “STOP_ON_FAILURE” option which
    can be used to stop running the tests once one has failed.

  • The “CTestCoverageCollectGCOV” module
    “ctest_coverage_collect_gcov()” command gained a
    “TARBALL_COMPRESSION” option to control compression of the tarball
    of collected results.

CPack

  • The “CPack Archive Generator”’s “TXZ” format learned the
    “CPACK_ARCHIVE_THREADS” variable to enable parallel compression.
    Requires support in the “liblzma” used by CMake.

  • The “CPack NSIS Generator” gained a new variable
    “CPACK_NSIS_MANIFEST_DPI_AWARE” to declare that the installer is
    DPI-aware.

  • The “CPack RPM Generator” gained “CPACK_RPM_PRE_TRANS_SCRIPT_FILE”
    “CPACK_RPM_POST_TRANS_SCRIPT_FILE” variables to specify pre- and
    post-trans scripts.

Other

  • “cmake-gui(1)” now populates its generator selection widget default
    value from the “CMAKE_GENERATOR” environment variable.
    Additionally, environment variables “CMAKE_GENERATOR_PLATFORM” and
    “CMAKE_GENERATOR_TOOLSET” are used to populate their respective
    widget defaults.

  • “ccmake(1)” learned to read a “CCMAKE_COLORS” environment variable
    to customize colors.

Deprecated and Removed Features

  • The “Documentation” module has been deprecated via “CMP0106”. This
    module was essentially VTK code that CMake should not be shipping
    anymore.

  • An explicit deprecation diagnostic was added for policy “CMP0070”
    and policy “CMP0071” (“CMP0069” and below were already deprecated).
    The “cmake-policies(7)” manual explains that the OLD behaviors of
    all policies are deprecated and that projects should port to the NEW
    behaviors.

Other Changes

  • On Windows, the “Ninja” and “Ninja Multi-Config” generators, when a
    compiler is not explicitly specified, now select the first compiler
    (of any name) found in directories listed by the “PATH” environment
    variable.

  • The “LINK_OPTIONS” and “INTERFACE_LINK_OPTIONS” target properties
    are now used for the device link step. See policy “CMP0105”.

  • Creation of an “ALIAS” target overwriting an existing target now
    raises an error. See policy “CMP0107”.

  • Linking a target to itself through an alias now raises an error. See
    policy “CMP0108”.

  • The “FindPackageHandleStandardArgs” module option “REQUIRED_VARS” is
    now optional if “HANDLE_COMPONENTS” is specified.

  • The “source_group()” command now also recognizes forward slashes as
    subgroup delimiters, not just backslashes.

  • “ctest(1)” now logs environment variables that it sets for each
    test, either due to the “ENVIRONMENT” property or the resource
    allocation feature, and submits this log to CDash. It does not log
    environment variables that were set outside of CTest.

  • When building CMake itself from source and not using a system-
    provided libcurl, HTTP/2 support is now enabled for commands
    supporting network communication via “http(s)”, such as
    “file(DOWNLOAD)”, “file(UPLOAD)”, and “ctest_submit()”. The
    precompiled binaries provided on “cmake.org” now support HTTP/2.

Changes made since CMake 3.18.0-rc1:

Ben Boeckel (18):

  • Help/dev: document other arguments to Do: test
  • ci: add a script to download Qt
  • gitlab-ci: test QtDialog on Windows
  • ci: add download information for Qt on macOS
  • gitlab-ci: test QtDialog on macOS
  • QCMakeCacheView: use non-deprecated List and Set constructions
  • gitlab-ci: move Makefiles Linux tests to use the package
  • ci: support running just a set of tests with external builders
  • Tests: add CUDA labels to tests which are affected by CUDA
  • gitlab-ci: add a cuda10.2 builder
  • gitlab-ci: rename some scripts to be Linux-specific
  • gitlab-ci: add an Xcode tester
  • ci: don’t test BundleGeneratorTest
  • gitlab-ci: split into multiple files
  • gitlab-ci: make rules a bit more uniform
  • gitlab-ci: add a comment describing what goes into a job
  • gitlab-ci: use extends
  • gitlab-ci: split linux and macos shared before scripts

Brad King (13):

  • VS: Restore compilation of ‘.C’ sources as C++
  • find_program: Revert “Find programs that are executable but not readable”
  • Tests: Factor out RunCMake.GenEx-COMPILE_LANGUAGE test
  • Tests: Factor out RunCMake.GenEx-COMPILE_LANG_AND_ID test
  • Tests: Factor out RunCMake.GenEx-LINK_LANGUAGE test
  • Tests: Factor out RunCMake.GenEx-LINK_LANG_AND_ID test
  • Tests: Factor out RunCMake.GenEx-HOST_LINK test
  • Tests: Factor out RunCMake.GenEx-DEVICE_LINK test
  • Tests: Factor out RunCMake.GenEx-TARGET_FILE test
  • Tests: Factor out RunCMake.GenEx-GENEX_EVAL test
  • Tests: Factor out RunCMake.file-GET_RUNTIME_DEPENDENCIES test
  • Tests: Shorten case names in RunCMake.file-GET_RUNTIME_DEPENDENCIES test
  • CMake 3.18.0-rc2

Raul Tambre (14):

  • FindCUDAToolkit: Re-unify with Internal/CUDAToolkit
  • FindCUDAToolkit: Add CUDAToolkit_LIBRARY_ROOT
  • FindCUDAToolkit: Compute CUDAToolkit_INCLUDE_DIR instead of searching
  • FindCUDAToolkit: Use list(SORT) to sort in natural order
  • FindCUDAToolkit: Remove unnecessary checks around searches
  • FindCUDAToolkit: Avoid unnecessary temporary variable computing binary dir
  • CUDA: Pass toolkit path to Clang
  • CUDA: Determine CUDA toolkit location for NVCC
  • Clang: Add final C++20 flag for Clang 11.0+
  • Clang: Record Clang 6.0+ as fully supporting C++17
  • CUDA: Add support for disabling CUDA_ARCHITECTURES
  • CUDA: Throw error for Clang on Windows
  • CUDA: Add issue number to Clang separable compilation error
  • Help: Mention CUDA Clang limitations in 3.18 release notes

Robert Maynard (2):

  • CUDA: Teach CMake that NVCC 11 supports cuda_std_17
  • Tests: Fix CudaOnly.StaticRuntimePlusToolkit build rpath

Ron Klein (1):

  • FindProtobuf: Fix typo in documentation