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Meson (software)

Meson
Developer(s)Jussi Pakkanen
Initial release2 March 2013; 11 years ago (2013-03-02)
Stable release
1.6.0[1] Edit this on Wikidata / 20 October 2024; 60 days ago (20 October 2024)
Repository
Written inPython
Operating systemCross-platform
TypeSoftware development tools
LicenseApache License 2.0
Websitemesonbuild.com Edit this on Wikidata

Meson (/ˈmɛ.sɒn/)[2] is a software build automation tool for building a codebase. Meson adopts a convention over configuration approach to minimize the data required to configure the most common operations.[3] Meson is free and open-source software under the Apache License 2.0.[4]

Meson is written in Python and runs on Unix-like (including Linux and macOS), Windows and other operating systems. It supports building C, C++, C#, CUDA, Objective-C, D, Fortran, Java, Rust, and Vala,.[5] It handles dependencies via a mechanism named Wrap. It supports GNU Compiler Collection (gcc), Clang, Visual C++ and other compilers, including non-traditional compilers such as Emscripten and Cython.[6] The project uses ninja as the primary backend buildsystem, but can also use Visual Studio or Xcode backends.

Meson's support for Fortran and Cython was improved to help various scientific projects in their switch from setuptools to Meson, for example SciPy.[7] Meson can be used as a PEP517 backend to build Python wheels, via the meson-python package.[8]

Language

The syntax of Meson's build description files, the Meson language, borrows from Python, but is not Python. It is designed such that it can be reimplemented in any other language;[9] for example, muon[10] is a C implementation, and Meson++[11] is a C++ implementation. The dependency on Python is an implementation detail.

The Meson language is intentionally not Turing-complete, and can therefore not express an arbitrary program.[9] Instead, arbitrary build steps beyond compiling supported languages can be represented as custom targets.

The Meson language is strongly typed, such that builtin types like library, executable, string, and lists thereof, are non-interchangeable.[12] In particular, unlike Make, the list type does not split strings on whitespace.[9] Thus, whitespace and other characters in filenames and program arguments are handled cleanly.

Speed and correctness

As with any typical buildsystem, correct incremental builds are the most significant speed feature (because all incremental progress is discarded whenever the user is forced to do a clean build).

Unlike bare Make, the separate configure step ensures that changes to arguments, environment variables and command output are not partially applied in subsequent builds, which would lead to a stale build.

Like Ninja, Meson does not support globbing of source files.[9] By requiring all source files to be listed in the build definition files, the build definition file timestamps are sufficient to determine whether the set of source files has changed, thereby ensuring that removed source files are detected. CMake supports globbing, but recommends against it for the same reason.[13]

Meson uses ccache automatically if installed. It also detects changes to symbol tables of shared libraries to skip relinking executables against the library when there are no ABI changes. Precompiled headers are supported, but require configuration. Debug builds are without optimization by default.

Features

A stated goal of Meson is to facilitate modern development practices. As such, Meson knows how to do unity builds, build with test coverage, link time optimization etc without the programmer having to write support for this.

Subprojects

Meson can automatically find and use external dependencies via pkg-config, CMake, and project-specific lookups,[14] but this only finds installed dependencies, which Meson can not do anything about. Alternatively, or as a fallback, a dependency can be provided as a subproject – a Meson project within another, either contained or as a download link, possibly with patches.[15] This lets Meson resolve dependency hell for the convenience of casual users who want to compile the project, but may contribute to software bloat if a common installed dependency could have been used instead. The mode favored by Linux packagers is therefore fallback.[16]

Meson supports Meson and CMake subprojects. A Meson build file may also refer to the WrapDB service.[15]

Cross compilation

Cross compilation requires extra configuration, which Meson supports in the form of a separate cross file, which can be external to the Meson project.[17]

Installation directory setup

Setting the library installation directory on x86_64 Unix is handled automatically by Meson, but not by other tools such as Autotools.

Adopters

Main page: Category:Software that uses Meson

GNOME has made it a goal to port its projects to Meson.[18] As of late 2017, GNOME Shell itself exclusively requires Meson after abandoning Autotools,[19] and central components like GTK+, Clutter-GTK, GLib and GStreamer can be built with Meson.[18]

Many freedesktop.org projects have switched to Meson. Systemd relies on Meson since dropping Autotools in version 234,[20] and also X.Org[21] and Mesa[22] were ported to Meson.

Feature comparison

Feature comparison with CMake and Make.

Feature Meson CMake Make
Datatypes Yes No No
List datatype Yes semicolon-delimited string whitespace-delimited string
Dictionary datatype since 0.47.0 No No
File globbing No Yes non-standard extension on some variants
Extensible via custom functions No Yes No
Can read output of arbitrary commands (at configure time) run_command Yes Yes
Can run arbitrary commands at build time as recipes of custom targets Yes Yes Yes
Prohibits stale builds (partial rebuild against input change) Yes (unless there are bugs)[contradictory] If not globbing source files[citation needed] Recursive Make (an idiomatic pattern) is broken in this respect[23]
The target that runs tests depends on the tests being built (e.g. test depends on all) Yes[citation needed] No, and add_dependencies(test all) is forbidden, because the test target is reserved.[24] Trivial to add[citation needed]
Ccache Automatic[citation needed] Trivial to add[citation needed] Trivial to add[citation needed]
Distcc Trivial to add[citation needed] Trivial to add[citation needed] Trivial to add[citation needed]
Symbol-table-aware relinking Yes[citation needed] Do it yourself[citation needed] Do it yourself[citation needed]
Precompiled headers Optional[citation needed] CMake ≥ 3.16[25][2] Do it yourself[citation needed]
Finding installed dependencies pkg-config, CMake packages CMake module, pkg-config -
Downloading dependencies automatically subproject FetchContent[26] -
Finding installed dependencies, with download fallback pkg-config + subproject CMake module/pkg-config + FetchContent -
pkg-config file generator Yes No -
Facilitate use as an auto-downloadable dependency Can be used as a Meson subproject No -

See also

References

  1. ^ "Release 1.6.0". 20 October 2024. Retrieved 22 October 2024.
  2. ^ a b "Making build systems not suck (linux.conf.au video)". YouTube. 16 January 2015.
  3. ^ "High productivity build system". Meson aims to optimize programmer productivity by providing simple, out-of-the-box support for modern software development tools and practices, such as unit tests, coverage reports, Valgrind, CCache and the like.
  4. ^ "mesonbuild/meson: The Meson Build System". GitHub. Retrieved 13 April 2016.
  5. ^ "Reference manual".
  6. ^ "Compiler IDs".
  7. ^ "How to build SciPy with Meson".
  8. ^ "meson-python package on PyPI".
  9. ^ a b c d "Meson Frequently Asked Questions".
  10. ^ "muon.build". Retrieved 27 January 2023.
  11. ^ Baker, Dylan (28 May 2021). "dcbaker/meson-plus-plus". GitHub. Retrieved 28 May 2021.
  12. ^ "Meson Syntax".
  13. ^ "CMake FILE command". Note: We do not recommend using GLOB to collect a list of source files from your source tree. If no CMakeLists.txt file changes when a source is added or removed, the generated build system cannot know when to ask CMake to regenerate.
  14. ^ "Dependencies with custom lookup functionality — Meson documentation".
  15. ^ a b "Wrap dependency system manual".
  16. ^ "Meson and 3rd party dependencies. Only one correct way".
  17. ^ "Cross compilation".
  18. ^ a b "GNOME Goal: Port modules to use Meson build system".
  19. ^ "GNOME 3.26 Beta Debuts: More Meson Porting, Wayland Action".
  20. ^ "Drop support for autotools". GitHub.
  21. ^ "Meson Support Has Landed In The X.Org Server".
  22. ^ "Mesa Developers Move Closer To Dropping Autotools Build System In Favor Of Meson".
  23. ^ "Non-recursive Make Considered Harmful" (PDF). Microsoft. Recursive Make is considered harmful for very good reasons (Miller 1998); it is not possible to accurately track dependencies when the build system is constructed of separate components that invoke each other.
  24. ^ "Make test does not depend on make all". Kitware issue tracker. 23 June 2016. Retrieved 3 September 2020.
  25. ^ "CMake support for precompiled headers". Retrieved 13 March 2018.
  26. ^ "FetchContent — CMake 3.15.7 Documentation".
Quelle: https://en.wikipedia.org/wiki/Meson_build_system