docs/devel/build-system.rst

22  - build artifacts in a subdir of QEMU source tree::
30 build artifacts cannot be placed in the source tree itself.
48  - create a virtual environment in which all Python code runs during
51  - invoke Meson in the virtual environment, to perform the actual
55 which a same-named Meson option exists; dashes in the command line are
80    Determine if $COMMAND exists in the current environment, either as a
82    replacement in Meson is ``find_program()``.
118    ``cc-option`` macro in ``pc-bios/option-rom/Makefile``).
128 An important step in ``configure`` is to create a Python virtual
131 from the environment, or the system PATH, in this order.  The venv resides
132 in the ``pyvenv`` directory in the build tree, and provides consistency
133 in how the build process runs Python code.
137 look for ``meson`` or ``sphinx-build`` binaries in the PATH;
140 PATH might operate in a different Python environment than the one chosen
144 was installed in the ``site-packages`` directory of another interpreter,
149 If not, ``configure`` can also optionally install dependencies in the
150 virtual environment with ``pip``, either from wheels in ``python/wheels``
159               Currently, in all cases it would be possible to use ``python -m``
167 The required versions of the packages are stored in a configuration file
174 good" version that is also listed in ``pythondeps.toml``.  In this
183 but are not available in all supported distros, are bundled with the
184 QEMU sources.  The only one is currently Meson (outdated in Ubuntu
187 In order to include a new or updated wheel, modify and rerun the
210 3) ROMs, whether provided as binary blobs in the QEMU distributions
218 though that might change in the future.
223 ``meson.build`` files group the source files in rules that are
245   Target-independent code lives in the ``common_ss``, ``system_ss`` and
247   ``system_ss`` only in system emulators, ``user_ss`` only in user-mode
251   In the target-dependent set lives CPU emulation, some device emulation and
254   in the ``specific_ss`` sourceset.
256   Each emulator also includes sources for files in the ``hw/`` and ``target/``
259   ``TARGET_ARCH``, as found in ``configs/targets/*.mak``.
261   Each subdirectory in ``hw/`` adds one sourceset to the ``hw_arch`` dictionary,
271   Each subdirectory in ``target/`` instead should add one sourceset to each
305   linked in some binaries, sometimes it requires hooks only in some of
308   into the binary if the real implementation is not present.  In a way,
313 The following files concur in the definition of which files are linked
328   device models.  They are described in :ref:`kconfig`
331   These files mostly define symbols that appear in the ``*-config-target.h``
358  - Add code to include the feature status in ``config-host.h``
360  - Add code to print out the feature status in the configure summary
364 in ``meson_options.txt``::
406 In case the script is not written in Python, use a ``#! /usr/bin/env ...``
409 Scripts written in Python, where it is desirable to make the script
412 should be invoked through the ``python`` variable in meson.build. For
423 By the time Meson runs, Python dependencies are available in the virtual
436 The next step in building QEMU is to invoke make.  GNU Make is required
441 just the emulators (namely firmware and the tests in ``tests/tcg``) which
447 Tests, whether defined in ``meson.build`` or not, are also ran by the
454 respectively to build emulators and run tests defined in meson.build.
455 The main difference is that ``make`` needs the ``-jN`` flag in order to
475 The following key files are statically defined in the source tree, with
481   of QEMU. The default 'all' target will naturally result in the build of
485   The meson.build file in the root directory is the main entry point for the
487   executables.  Build rules for various subdirectories are included in
492   It handles creating the virtual environment, creating scripts in
500   included directly by the top level Makefile, anything defined in this
505   included directly by the top level Makefile, anything defined in this
511 The following files are generated at run-time in order to control the
514 generates ``Makefile`` from ``Makefile.in``.
520   will write the paths to various tools to this file, for use in ``Makefile``
586   Makefile is mostly a list of targets that Meson included in build.ninja.
589   The Makefile definitions that let "make check" run tests defined in