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Paulo Zanoni b0653370d0 vulkan: don't zero-initialize STACK_ARRAY()'s stack array
STACK_ARRAY() is used in a lot of places. When games are running we
see STACK_ARRAY() arrays being used all the time: each queue
submission uses 6, WaitSemaphores and syncobj waiting also uses them:
they're constantly present in Vulkan runtime.

There's no need for STACK_ARRAY()'s stack array to be initialized,
callers cannot not depend on it. If the number of elements is greater
than STACK_ARRAY_SIZE, then STACK_ARRAY() will just malloc() the array
and return it not initialized: anybody depending of
zero-initialization is going to break when the array is big.

The reason why we're zero-intializing STACK_ARRAY()'s stack array is
to silence -Wmaybe-uninitialized warnings: see commit d7957df318
("vulkan: fix uninitialized variables"). I don't think that commit is
the ideal way to deal with the problem, so this patch proposes a
better solution.

The problem here is that zero-initializing it adds code we don't need
for every single caller. STACK_ARRAY() already has 63 callers and only
3 of them are affected by the -Wmaybe-uninitialized warining. So here
we undo what commit d7957df318 did and instead we fix the 3 cases
that actually generate the -Wmaybe-uninitialized warnings.

Gcc is only emitting those warinings because it knows that the number
of elements in the array may be zero, so the loops we have that set
elements to the array may end up do nothing, and then we pass the
array uninitialized to other functions.

For the cases related to vk_sync this is just returning VK_SUCCESS
earlier, instead of relying on the check that eventually happens at
__vk_sync_wait_many(). For the vkCmdWaitEvents() function, the Vulkan
spec says that "eventCount must be greater than 0", so the early
return doesn't hurt anybody either. In both cases we make the zero
case faster by not defining an 8-sized array, zero-initializing it,
then returning success without using it.

Reference: d7957df318 ("vulkan: fix uninitialized variables")
Acked-by: Yonggang Luo <luoyonggang@gmail.com>
Reviewed-by: Yiwei Zhang <zzyiwei@chromium.org>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28288>
2024-04-08 17:23:25 +00:00
.ci-farms Revert "ci: disable Collabora's farm due to maintance" 2024-04-08 16:37:33 +00:00
.ci-farms-disabled Revert "ci: disable Collabora's farm due to maintance" 2024-04-08 16:37:33 +00:00
.github/workflows add zink to macos ci 2022-11-22 19:04:13 +00:00
.gitlab gitlab: make commit more commit-like formatted 2023-11-09 17:30:07 +00:00
.gitlab-ci ci: explicitly disable glvnd to avoid regression when making it auto 2024-04-06 18:40:46 +00:00
android nouveau: import libdrm_nouveau 2024-03-13 15:21:07 +00:00
bin ci_run_n_monitor: explain how to pass multiple targets without having to use regexes 2024-03-29 19:23:24 +00:00
build-support configure: commit test files 2017-10-16 16:32:43 -07:00
docs radv: enable VK_EXT_shader_object by default 2024-04-08 08:36:14 +00:00
include intel/dev: Add 0x56be and 0x56bf DG2 PCI IDs 2024-04-05 06:36:44 +00:00
src vulkan: don't zero-initialize STACK_ARRAY()'s stack array 2024-04-08 17:23:25 +00:00
subprojects meson: Update wayland-protocols wrap to 1.34 2024-04-02 13:09:37 +00:00
.clang-format meson: enable the clang-format target 2023-05-29 11:57:08 +00:00
.clang-format-ignore ci: enforce formatting for RADV & ACO 2023-06-16 19:59:52 +00:00
.clang-format-include teflon: Initial commit 2024-01-24 10:02:10 +00:00
.dir-locals.el
.editorconfig glsl: Fixes ident issue in glsl_parser.yy and update editorconfig for it 2022-12-16 19:02:17 +00:00
.git-blame-ignore-revs freedreno: Add reformatting commits to .git-blame-ignore-revs 2023-09-22 02:07:36 +00:00
.gitattributes gitlab: Highlight .cl as C 2023-11-02 11:37:46 +00:00
.gitignore .gitignore: Add .venv folder 2024-01-24 10:53:14 +00:00
.gitlab-ci.yml ci: raise the log level threshold of spirv logs 2024-04-02 17:25:42 +00:00
.graphqlrc.yml ci/bin: Add utility to find jobs dependencies 2022-08-03 23:10:37 +00:00
.mailmap .mailmap: add an alias for Christian Gmeiner 2023-06-08 09:16:25 +00:00
.mr-label-maker.yml mr-label-maker: be explicit about the various CI files 2024-04-08 13:33:51 +00:00
CODEOWNERS CODEOWNERS: update Imagination maintainers 2024-01-19 10:26:15 +00:00
meson.build meson: turn glvnd option into a feature 2024-04-06 18:40:46 +00:00
meson_options.txt meson: auto-enable glvnd when libglvnd is installed 2024-04-06 18:40:47 +00:00
README.rst docs: promote #dri-devel on oftc over freenode 2021-05-24 09:21:48 +00:00
VERSION VERSION: bump to 24.1 2024-01-11 11:05:47 +00:00

`Mesa <https://mesa3d.org>`_ - The 3D Graphics Library
======================================================


Source
------

This repository lives at https://gitlab.freedesktop.org/mesa/mesa.
Other repositories are likely forks, and code found there is not supported.


Build & install
---------------

You can find more information in our documentation (`docs/install.rst
<https://mesa3d.org/install.html>`_), but the recommended way is to use
Meson (`docs/meson.rst <https://mesa3d.org/meson.html>`_):

.. code-block:: sh

  $ mkdir build
  $ cd build
  $ meson ..
  $ sudo ninja install


Support
-------

Many Mesa devs hang on IRC; if you're not sure which channel is
appropriate, you should ask your question on `OFTC's #dri-devel
<irc://irc.oftc.net/dri-devel>`_, someone will redirect you if
necessary.
Remember that not everyone is in the same timezone as you, so it might
take a while before someone qualified sees your question.
To figure out who you're talking to, or which nick to ping for your
question, check out `Who's Who on IRC
<https://dri.freedesktop.org/wiki/WhosWho/>`_.

The next best option is to ask your question in an email to the
mailing lists: `mesa-dev\@lists.freedesktop.org
<https://lists.freedesktop.org/mailman/listinfo/mesa-dev>`_


Bug reports
-----------

If you think something isn't working properly, please file a bug report
(`docs/bugs.rst <https://mesa3d.org/bugs.html>`_).


Contributing
------------

Contributions are welcome, and step-by-step instructions can be found in our
documentation (`docs/submittingpatches.rst
<https://mesa3d.org/submittingpatches.html>`_).

Note that Mesa uses gitlab for patches submission, review and discussions.