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712f99934c
The current SSA def validation we do in nir_validate validates three
things:
1. That each SSA def is only ever used in the function in which it is
defined.
2. That an nir_src exists in an SSA def's use list if and only if it
points to that SSA def.
3. That each nir_src is in the correct use list (uses or if_uses) based
on whether it's an if condition or not.
The way we were doing this before was that we had a hash table which
provided a map from SSA def to a small ssa_def_validate_state data
structure which contained a pointer to the nir_function_impl and two
hash sets, one for each use list. This meant piles of allocation and
creating of little hash sets. It also meant one hash lookup for each
SSA def plus one per use as well as two per src (because we have to look
up the ssa_def_validate_state and then look up the use.) It also
involved a second walk over the instructions as a post-validate step.
This commit changes us to use a single low-collision hash set of SSA
sources for all of this by being a bit more clever. We accomplish the
objectives above as follows:
1. The list is clear when we start validating a function. If the
nir_src references an SSA def which is defined in a different
function, it simply won't be in the set.
2. When validating the SSA defs, we walk the uses and verify that they
have is_ssa set and that the SSA def points to the SSA def we're
validating. This catches the case of a nir_src being in the wrong
list. We then put the nir_src in the set and, when we validate the
nir_src, we assert that it's in the set. This takes care of any
cases where a nir_src isn't in the use list. After checking that
the nir_src is in the set, we remove it from the set and, at the end
of nir_function_impl validation, we assert that the set is empty.
This takes care of any cases where a nir_src is in a use list but
the instruction is no longer in the shader.
3. When we put a nir_src in the set, we set the bottom bit of the
pointer to 1 if it's the condition of an if. This lets us detect
whether or not a nir_src is in the right list.
When running shader-db with an optimized debug build of mesa on my
laptop, I get the following shader-db CPU times:
With NIR_VALIDATE=0 3033.34 seconds
Before this commit 20224.83 seconds
After this commit 6255.50 seconds
Assuming shader-db is a representative sampling of GLSL shaders, this
means that making this change yields an 81% reduction in the time spent
in nir_validate. It still isn't cheap but enabling validation now only
increases compile times by 2x instead of 6.6x.
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Thomas Helland <thomashelland90@gmail.com>
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| .dir-locals.el | ||
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| CleanSpec.mk | ||
| common.py | ||
| meson.build | ||
| meson_options.txt | ||
| README.rst | ||
| REVIEWERS | ||
| SConstruct | ||
| VERSION | ||
`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.html <https://mesa3d.org/install.html>`_), but the recommended way is to use Meson (`docs/meson.html <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 `Freenode's #dri-devel <irc://chat.freenode.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.html <https://mesa3d.org/bugs.html>`_). Contributing ------------ Contributions are welcome, and step-by-step instructions can be found in our documentation (`docs/submittingpatches.html <https://mesa3d.org/submittingpatches.html>`_). Note that Mesa uses email mailing-lists for patches submission, review and discussions.