CMake 3.19.0-rc1 is ready for testing

Announcements
1

I am proud to announce the first CMake 3.19 release candidate.
https://cmake.org/download/

Documentation is available at:
https://cmake.org/cmake/help/v3.19

Release notes appear below and are also published at
https://cmake.org/cmake/help/v3.19/release/3.19.html

Some of the more significant changes in CMake 3.19 are:

  • “cmake(1)” and “cmake-gui(1)” now recognize “CMakePresets.json” and
    “CMakeUserPresets.json” files.

  • The “Xcode” generator now uses the Xcode “new build system” when
    generating for Xcode 12.0 or higher. See the
    “CMAKE_XCODE_BUILD_SYSTEM” variable. One may use “-T buildsystem=1”
    to switch to the legacy build system.

  • The Visual Studio Generators for VS 2015 and above gained support
    for the Visual Studio Tools for Android. One may now set
    “CMAKE_SYSTEM_NAME” to “Android” to generate “.vcxproj” files for
    the Android tools.

  • CMake learned to support “ISPC” as a first-class language that can
    be enabled via the “project()” and “enable_language()” commands.
    “ISPC” is currently supported by the Makefile Generators and the
    “Ninja” generator on Linux, macOS, and Windows using the Intel ISPC
    compiler.

  • “CUDA” language support for Clang now supports separable compilation
    (“CUDA_SEPARABLE_COMPILATION”)

  • The “CMake GUI” now has an environment variable editor.

  • The “cmake_path()” command was added for operations on filesystem
    paths.

  • The “file(GENERATE)” command gained a new “TARGET” keyword to
    support resolving target-dependent generator expressions.

  • The “CMAKE_OPTIMIZE_DEPENDENCIES” variable was added to initialize
    the new “OPTIMIZE_DEPENDENCIES” target property and avoid
    unnecessarily building dependencies for a static library.

  • The “CheckCompilerFlag” module has been added to generalize
    “CheckCCompilerFlag” and “CheckCXXCompilerFlag” to more languages.
    It also supports the “CUDA” and “ISPC” languages.

  • The “CheckSourceCompiles” module has been added to generalize
    “CheckCSourceCompiles” and “CheckCXXSourceCompiles” to more
    languages. It also supports the “CUDA” and “ISPC” languages.

  • The “CheckSourceRuns” module has been added to generalize
    “CheckCSourceRuns” and “CheckCXXSourceRuns” to more languages. It
    also supports the “CUDA” language.

  • The “FindCUDAToolkit” module gained support for finding CUDA
    toolkits that do not contain “nvcc”, as well as for finding
    scattered toolkit installations when cross-compiling.

  • Interface Libraries may now have source files added via
    “add_library()” or “target_sources()”. Those with sources will be
    generated as part of the build system.

  • Compatibility with versions of CMake older than 2.8.12 is now
    deprecated and will be removed from a future version. Calls to
    “cmake_minimum_required()” or “cmake_policy()” that set the policy
    version to an older value now issue a deprecation diagnostic.

CMake 3.19 Release Notes

Changes made since CMake 3.18 include the following.

New Features

Presets

  • “cmake(1)” and “cmake-gui(1)” now recognize “CMakePresets.json” and
    “CMakeUserPresets.json” files.

Generators

  • The “Xcode” generator now uses the Xcode “new build system” when
    generating for Xcode 12.0 or higher. See the
    “CMAKE_XCODE_BUILD_SYSTEM” variable. One may use “-T buildsystem=1”
    to switch to the legacy build system.

  • The “Xcode” generator gained support for linking libraries and
    frameworks via the Link Binaries With Libraries build phase
    instead of always by embedding linker flags directly. This behavior
    is controlled by a new “XCODE_LINK_BUILD_PHASE_MODE” target
    property, which is initialized by a new
    “CMAKE_XCODE_LINK_BUILD_PHASE_MODE” variable.

  • The Visual Studio Generators for VS 2015 and above gained support
    for the Visual Studio Tools for Android. One may now set
    “CMAKE_SYSTEM_NAME” to “Android” to generate “.vcxproj” files for
    the Android tools.

Languages

  • CMake learned to support “ISPC” as a first-class language that can
    be enabled via the “project()” and “enable_language()” commands.
    “ISPC” is currently supported by the Makefile Generators and the
    “Ninja” generator on Linux, macOS, and Windows using the Intel ISPC
    compiler.

  • “CUDA” language support for Clang now includes:

    • separable compilation (“CUDA_SEPARABLE_COMPILATION”), and

    • finding scattered toolkit installations when cross-compiling.

File-Based API

  • The “cmake-file-api(7)” “codemodel” version 2 “version” field has
    been updated to 2.2.

  • The “cmake-file-api(7)” “codemodel” version 2 “target” object gained
    a new “languageStandard” field in the “compileGroups” objects.

Command-Line

  • The “cmake(1)” command-line tool’s “–install” mode gained a “–
    default-directory-permissions” option.

  • “cmake(1)” gained a “-E create_hardlink” command-line tool that can
    be used to create hardlinks between files.

GUI

  • The “CMake GUI” now has an environment variable editor.

Commands

  • The “add_test()” command now (officially) supports whitespace and
    other special characters in the name for the test it creates. See
    policy “CMP0110”.

  • The “cmake_language()” command gained a “DEFER” mode to schedule
    command calls to occur at the end of processing a directory.

  • The “cmake_path()” command was added for operations on filesystem
    paths.

  • The “configure_file()” command gained a “NO_SOURCE_PERMISSIONS”
    option to suppress copying the input file’s permissions to the
    output file.

  • The “execute_process()” command gained a “COMMAND_ERROR_IS_FATAL”
    option to specify a fatal error.

  • The “file(ARCHIVE_CREATE)” command gained a “COMPRESSION_LEVEL”
    option to specify the compression level.

  • The “file(CHMOD)” and “file(CHMOD_RECURSE)” subcommands were added
    to set permissions of files and directories.

  • The “file(DOWNLOAD)” command “<file>” argument is now optional. If
    it is not specified, the file is not saved.

  • The “file(GENERATE)” command gained a new “TARGET” keyword to
    support resolving target-dependent generator expressions.

  • The “file()” gained sub-command REAL_PATH to compute a path with
    symlinks resolved.

  • The “find_package()” command learned to handle a version range.

  • The “separate_arguments()” command gained new “PROGRAM” option to
    search program.

  • The “set_property()”, “get_property()”, and
    “get_directory_property()” commands’ “DIRECTORY” options now accept
    references to binary directory paths, such as the value of
    “CMAKE_CURRENT_BINARY_DIR”.

  • The “string()” command gained set of new “JSON” sub commands to
    provide JSON parsing capabilities.

Variables

  • The “CMAKE_CLANG_VFS_OVERLAY” variable was added to tell Clang to
    use a VFS overlay to support the Windows SDK when cross-compiling
    from hosts with case-sensitive filesystems.

  • The “CMAKE_MFC_FLAG” variable now supports generator expressions.

  • The “CMAKE_OPTIMIZE_DEPENDENCIES” variable was added to initialize
    the new “OPTIMIZE_DEPENDENCIES” target property and avoid
    unnecessarily building dependencies for a static library.

  • The “CMAKE_VS_WINDOWS_TARGET_PLATFORM_VERSION_MAXIMUM” variable was
    added to tell the Visual Studio Generators what maximum version of
    the Windows SDK to choose.

Properties

  • The “EXCLUDE_FROM_ALL” target property now supports “generator
    expressions”.

  • The “OPTIMIZE_DEPENDENCIES” target property was added to avoid
    unnecessarily building dependencies for a static library.

  • The “PCH_INSTANTIATE_TEMPLATES” target property was added to enable
    template instantiation in the precompiled header. This is enabled by
    default and offers a roughly 20% compile time improvement. Currently
    only supported by Clang 11.

  • The “WIN32_EXECUTABLE” target property now supports “generator
    expressions”.

Modules

  • The “CheckCompilerFlag” module has been added to generalize
    “CheckCCompilerFlag” and “CheckCXXCompilerFlag” to more languages.
    It also supports the “CUDA” and “ISPC” languages.

  • The “CheckLinkerFlag” module now supports the “CUDA” language.

  • The “CheckSourceCompiles” module has been added to generalize
    “CheckCSourceCompiles” and “CheckCXXSourceCompiles” to more
    languages. It also supports the “CUDA” and “ISPC” languages.

  • The “CheckSourceRuns” module has been added to generalize
    “CheckCSourceRuns” and “CheckCXXSourceRuns” to more languages. It
    also supports the “CUDA” language.

  • “CMakePackageConfigHelpers” module learned to manage version range.

  • The “FindCUDAToolkit” module gained support for finding CUDA
    toolkits that do not contain “nvcc”, as well as for finding
    scattered toolkit installations when cross-compiling.

  • The “FindPackageHandleStandardArgs” module learned to handle version
    range. It also gained the “find_package_check_version()” command to
    check the validity of a version against version-related arguments of
    “find_package()” command.

  • The “FindPython3”, “FindPython2” and “FindPython” modules gained the
    capability to manage a version range.

  • The “FindPython3”, “FindPython2” and “FindPython” modules provide,
    respectively, the variable “Python3_LINK_OPTIONS”,
    “Python2_LINK_OPTIONS” and “Python_LINK_OPTIONS” for link options.

  • The “FindSDL” module now provides:

    • imported target “SDL::SDL”,

    • result variables “SDL_LIBRARIES” and “SDL_INCLUDE_DIRS”,

    • version variables “SDL_VERSION”, “SDL_VERSION_MAJOR”
      “SDL_VERSION_MINOR”, and “SDL_VERSION_PATCH”.

  • “FindSWIG” module gains the capability to manage a version range.

  • The “FindTIFF” module gained a “CXX” component to find the “tiffxx”
    library containing C++ bindings.

  • The “FindVulkan” module now provides a “Vulkan::glslc” imported
    target and associated “Vulkan_GLSLC_EXECUTABLE” variable which
    contain the path to the GLSL SPIR-V compiler.

  • “UseSWIG” module gains new source file properties “OUTPUT_DIR” and
    “OUTFILE_DIR” to manage output directories on per source basis.

CTest

  • “ctest(1)” now supports “compute-sanitizer” (“cuda-memcheck”) as
    “CTEST_MEMORYCHECK_COMMAND”. The different tools (memcheck,
    racecheck, synccheck, initcheck) supplied by “compute-sanitizer” can
    be selected by adding appropriate flags to the
    “CTEST_MEMORYCHECK_COMMAND_OPTIONS” variable. The default flags are
    “–tool memcheck --leak-check full”.

CPack

  • CPack gained the “CPACK_PRE_BUILD_SCRIPTS”,
    “CPACK_POST_BUILD_SCRIPTS”, and “CPACK_PACKAGE_FILES” variables.

  • The “CPack External Generator” gained the
    “CPACK_EXTERNAL_BUILT_PACKAGES” variable.

  • The “CPack WIX Generator” gained a “CPACK_WIX_CUSTOM_XMLNS” option
    to specify custom XML namespaces.

Other

  • Interface Libraries may now have source files added via
    “add_library()” or “target_sources()”. Those with sources will be
    generated as part of the build system.

Deprecated and Removed Features

  • Compatibility with versions of CMake older than 2.8.12 is now
    deprecated and will be removed from a future version. Calls to
    “cmake_minimum_required()” or “cmake_policy()” that set the policy
    version to an older value now issue a deprecation diagnostic.

  • An explicit deprecation diagnostic was added for policy “CMP0071”
    (“CMP0071” 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.

  • macOS SDKs older than 10.5 are no longer supported.

  • “cmake-gui(1)” now requires Qt5. Support for compiling with Qt4 has
    been removed.

  • The “cmake(1)” command-line option “–warn-unused-vars” has been
    removed and is now silently ignored. The option has not worked
    correctly since CMake 3.3.

Documentation

The following guides have been added:

  • “IDE Integration Guide”

  • “Importing and Exporting Guide”

Other Changes

  • Building for macOS will now use the latest SDK available on the
    system, unless the user has explicitly chosen a SDK using
    “CMAKE_OSX_SYSROOT”. The deployment target or system macOS version
    will not affect the choice of SDK.

  • The “CMAKE_<LANG>_COMPILER” variable may now be used to store
    “mandatory” compiler flags like the “CC” and other environment
    variables.

  • The “CMAKE_<LANG>_FLAGS_INIT” variable will now be considered during
    the compiler identification check if other sources like
    “CMAKE_<LANG>_FLAGS” or “CFLAGS” are not set.

  • The “find_program()” command now requires permission to execute but
    not to read the file found. See policy “CMP0109”.

  • An imported target with a missing location now fails during
    generation if the location is used. See policy “CMP0111”.

  • The following target-based generator expressions that query for
    directory or file name components no longer add a dependency on the
    evaluated target. See policy “CMP0112”.

    • “TARGET_FILE_DIR”

    • “TARGET_LINKER_FILE_BASE_NAME”

    • “TARGET_LINKER_FILE_NAME”

    • “TARGET_LINKER_FILE_DIR”

    • “TARGET_SONAME_FILE_NAME”

    • “TARGET_SONAME_FILE_DIR”

    • “TARGET_PDB_FILE_NAME”

    • “TARGET_PDB_FILE_DIR”

    • “TARGET_BUNDLE_DIR”

    • “TARGET_BUNDLE_CONTENT_DIR”

  • Makefile Generators no longer repeat custom commands from target
    dependencies. See policy “CMP0113”.

  • The “ExternalProject” module handling of step target dependencies
    has been revised. See policy “CMP0114”.

  • The “OSX_ARCHITECTURES” target property is now respected for the
    “ASM” language.

  • If “CUDA” compiler detection fails with user-specified
    “CMAKE_CUDA_ARCHITECTURES” or “CMAKE_CUDA_HOST_COMPILER”, an error
    is raised.

2 Likes
2

Just a note for those who might see a similar issue - we had already defined a basic CHECK_COMPILER_FLAG macro in our build code, and with 3.19 the interaction between the new module and our old macro caused a recursive error:

Modules/CheckCCompilerFlag.cmake:40 (check_compiler_flag):
Maximum recursion depth of 1000 exceeded

We can avoid the issue in our logic by checking for a definition before we define our macro, using the more sophisticated one in CMake if available and preserving the old definition as a fallback:

if(NOT COMMAND CHECK_COMPILER_FLAG)
macro(CHECK_COMPILER_FLAG FLAG_LANG NEW_FLAG RESULTVAR)
…
endmacro()
endif(NOT COMMAND CHECK_COMPILER_FLAG)

3

Can you explain this more? I’m using imported targets to import libraries from an external build system that is built using add_custom_target. Of course, those files don’t exist until you actually build the project. I’m not seeing any warnings when testing with cmake 3.19, so maybe I’m not hitting this?

4

It is referring to the code not setting IMPORTED_LOCATION or equivalent when it should. The existence of the actual file on disk is unrelated.

1 Like
5

I was also confused by this. Might be worth re-wording to “missing LOCATION property” or something along those lines.

1 Like
6

I’ve opened CMake MR 5385 to clarify that the CMP0111 error is about the property setting and not the file on disk.

1 Like
7

Thanks, Brad!

8

Small bug:

$ cmake --profiling-output
terminate called after throwing an instance of 'std::out_of_range'
  what():  basic_string::substr: __pos (which is 19) > this->size() (which is 18)
Aborted

I am aware it requires the =sometihng part but it definitely shouldn’t call an abort() but print a proper message. cmake --profiling-format also aborts.
My cmake version:

$ cmake --version
cmake version 3.19.0-rc1

Compiler clang 12

9

Thanks for reporting this issue, you can track progress on the fix at: https://gitlab.kitware.com/cmake/cmake/-/issues/21351

10

I found another bug with handling generated sources whose names contain the $<CONFIG> generator-expressions.

I filed an issue [1] and already have a fix for it [2].

I think this fix should also go into CMake 3.19.0. It belongs to the other fixes ([3], [4]) regarding generated sources, that already made it into CMake 3.19.

(BTW: These fixes are not mentioned in the release-notes. Maybe it is worth mentioning that handling generated sources whose names contain the $<CONFIG> generator-expression now work in several situations, where they did not work before.)

[1] https://gitlab.kitware.com/cmake/cmake/-/issues/21349
[2] https://gitlab.kitware.com/cmake/cmake/-/merge_requests/5410
[3] https://gitlab.kitware.com/cmake/cmake/-/issues/21198
[4] https://gitlab.kitware.com/cmake/cmake/-/issues/21203

11

@dbahadir thanks for those fixes. We typically don’t mention general bug fixes for existing interfaces in release notes.