We're explicitly replacing zero with one in the only place where the
plane count being zero or one makes a difference. It also make sense:
UNKNOWN is used for buffers, which for all intents and purposes have one
plane.
Otherwise ubsan reports runtime errors such as:
libs/vkd3d-shader/ir.c:4731:5: runtime error: null pointer passed as argument 1, which is declared to never be null
Currently, when using Vulkan heaps, we create descriptor set
layouts with as many descriptors as allowed by the Vulkan
implementation limits. For some implementations this can mean
hundreds of millions of descriptors or more, which is wasteful,
given that even on the best resource binding tier Direct3D 12
applications should not expect to have more than a million usable
descriptors.
Recently this began being a problem, because since Mesa 24.2.7
the Intel driver advertises more than 200 million descriptors,
but pipeline compilation takes linear RAM in the number of
descriptors declared in the pipeline layout. This means that
compiling even a simple shader requires 10-20 GB of RAM.
In order to avoid using too much memory, with this commit we clamp
the number of descriptors declared in the set layouts to how many
we actually need to guarantee tier 3 resource binding support.
Creating a pool of 16k descriptors is wasteful if an allocator only uses
a fraction of them, so start at 1k and double for each subsequent
allocation until 16k is reached.
Now that our Vulkan descriptor sets contain only a single vkd3d
descriptor type, we're able to create descriptor pools containing only a
single vkd3d descriptor type as well. This avoids wasting unallocated
descriptors of one type when we run out of descriptors of another type.
We currently create statically sized descriptor pools, shared among
different descriptor types. Once we're unable to allocate a descriptor
set from a pool, we create a new pool. The unfortunate but predictable
consequence is that when we run out of descriptors of one type, we waste
any unallocated descriptors of the other types.
Dynamically adjusting the pool sizes could mitigate the issue, but it
seems non-trivial to handle all the edge cases, particularly in
situations where the descriptor count ratios change significantly
between frames. Instead, by storing only a single vkd3d descriptor type
in each Vulkan descriptor set we're able to create separate descriptor
pools for each vkd3d descriptor type, which also avoids the issue.
The main drawback of using separate descriptor sets for each descriptor
type is that we can no longer pack all bounded descriptor ranges into a
single descriptor set, potentially leaving fewer descriptor sets
available for unbounded ranges. That seems worth it, but we may end up
having to switch to a more complicated strategy if this ends up being a
problem on Vulkan implementations with a very limited number of
available descriptor sets.
ERR is used to indicate internal inconsistencies in vkd3d. Here that's
not the case, we simply have to forward the error condition to the
caller.
This fixes failures on the CI with llvmpipe, because the build we use is
compiled without support for VK_KHR_surface and related extensions.
Without LTO, gcc doesn't know that hresult_from_vk_result() will always return a
failure HRESULT for a failure VkResult, and so thinks that we might exit from
vkd3d_check_device_extensions() with a success HRESULT but without initializing
vk_extensions.
Currently the mutable descriptor set is repeated many times in the
pipeline layout in order to cover the indices for all the
descriptor types that would be present if mutable descriptors were
not used. This is useless and wasteful, but was necessary before
the descriptor sets backing the SRV-UAV-CBV heap were moved at the
end of the allocation table because descriptor set indices are
currently a compile-time constant in many places.
Now this is not needed any more and we can just avoid putting
many copies of the mutable descriptor set in the pipeline layout,
making it easier to meet Vulkan implementation limits.
So that when mutable descriptors are in use we can avoid putting
the other descriptor sets backing the SRV-UAV-CBV descriptor heap
in the pipeline layout altogether.
So we avoid hardcoding that it is number zero. There are two
goals here: first making the code easier to understand and
second allow reshuffling the descriptor set allocation in a
later commit.
