It is possible in SPIR-V to declare multiple specialization constants
with the same constant ID. The most common cause of this in GLSL is
defining a spec constant, then declaring the workgroup size to use that
spec constant by its ID. But, MSL forbids defining multiple function
constants with the same function constant ID. So, we must only emit one
definition of the actual function constant (with the
`[[function_constant(id)]]` attribute); but we can point the other
variables at this one definition.
Fixes three tests in the Vulkan CTS under
`dEQP-VK.compute.basic.max_local_size_*`.
Some Metal devices have a bug with depth array textures using comparison
with explicit LoD, where the LoD given will be biased by some amount.
For these devices, we can use a gradient instead, which does not exhibit
this problem. As with the fragment demote workaround, this is only
expected to be needed until the bug is fixed in Metal.
Vulkan specifies round-to-nearest-even mode to round array coordinates.
But we were using `round()`, which is round-to-nearest-away-from-zero.
Instead, use `rint()`, which is specified to perform nearest-even
rounding in MSL.
By default, the matrix would be declared as mediump, causing precision
issues. Need to dispatch to two separate functions since GLSL does not
support overload based on precision.
Undef values may be of struct type and may be used in constants.
Therefore, they must be interleaved with constants and types.
Fixes the rest of the Vulkan CTS test
`dEQP-VK.spirv_assembly.instruction.compute.opundef.undefined_spec_constant_composite`.
(Please excuse the churn in the reference output; it's an inevitable
result of this change.)
Fixes the CTS test
`dEQP-VK.spirv_assembly.instruction.compute.opundef.undefined_constant_composite`
and helps with another,
`dEQP-VK.spirv_assembly.instruction.compute.opundef.undefined_spec_constant_composite`.
Unfortunately, fixing the latter requires another change.
Some Metal devices have a bug where storage resources can still be
written to even if the fragment is discarded. This is obviously a bug in
Metal, but bothering Apple to fix it will only fix it for newer
versions; therefore, a workaround is needed for older versions. I have
made this an option so that, in case the bug is ever fixed, the
workaround can be disabled.
This workaround is simple: if a fragment shader may discard its fragment
and writes to a storage resource, a variable representing the
`HelperInvocation` built-in is created and passed to all functions. The
flag is checked on all resource writes; writes do not occur when
`HelperInvocation` is `true`. This relies on the earlier workaround to
update `HelperInvocation` when the fragment is discarded.
Fixes at least 3 failures in the CTS.
It is possible to pass unsigned integers to `OpSMulExtended`. In that
case, we want to do a signed multiply with sign extension, so make sure
the operands are forced to be interpreted as signed.
This was an oversight on my part when I added these instructions.
Fixes the CTS test
`dEQP-VK.spirv_assembly.instruction.compute.signed_op.uint_smulextended`.
Some Metal devices have a bug where `simd_is_helper_thread()` won't
return true after a fragment has been discarded. We can work around this
by manually setting `gl_HelperInvocation` upon discarding a fragment.
This is fairly unintrusive, so it is enabled by default. I've made it an
option so that, when the bug is fixed, we can disable it.
The array mechanism breaks DXC which needs to observe that all
components have been written.
Uninitialized outputs will be undefined. Resort to simple vector
instead.
This op creates a new composite constant with one element replaced. So,
we reconstruct the `SPIRConstant` for the composite constant, but with
one of the IDs replaced. Constant initializer lists are memoized for
when the result of a `CompositeInsert` is used in another
`CompositeInsert`.
(I wanted to add a test case for GLSL as well, but for two things:
1. `glslang` in Vulkan mode chokes on the first constant array,
insisting that its initializer needs to be a constant. [Bug in
glslang?]
2. The declarations for the buffers used by the shader aren't emitted,
regardless of whether Vulkan mode is enabled.)
Fixes five tests under
`dEQP-VK.spirv_assembly.instruction.*.opspecconstantop.vector_related`.
restrict was supported, but it broke in MSL 3.0. __restrict works on all
versions, so opt for that instead.
Also check for RestrictPointer decoration and refactor to_restrict() to
not take optional parameter to make it more obvious when implied space
character is added.
Flattening doesn't play well with dynamic indices. In this case, it's
better to leave it as an array of structs.
(I wanted to do this for named blocks generally. Trouble is, the builtin
`gl_out` block is *also* a named block...)
Fixes six more CTS tests, under
`dEQP-VK.tessellation.user_defined_io.per_patch_block_array.*`.
Using vertex-style stage input is complex, and it doesn't support
nesting of structures or arrays. By using raw buffer input instead, we
get this support "for free," and everything becomes much simpler.
Arguably, this is the way I should've done this in the first place.
Eventually, I'd like to make this the default, and then remove the
option altogether. (And I still need to do that with
`multi_patch_workgroup`...)
Should help fix 66 tests in the Vulkan CTS, under the following trees:
- `dEQP-VK.pipeline.*.interface_matching.*`
- `dEQP-VK.tessellation.user_defined_io.*`
- `dEQP-VK.clipping.user_defined.*`
It is allowed to redeclare descriptors with different types in Vulkan.
MSL in general does not allow this, but for raw buffers, we can cast the
reference type at the very least.
For typed resources we are kinda hosed. Without descriptor indexing's
PARTIALLY_BOUND_BIT, descriptors must be valid if they are statically
accessed, so it would not be valid to access differently typed aliases
unless that flag is used. There might be a way to reinterpret cast
descriptors, but that seems very sketchy.
Implements support for:
- Single discrete descriptor
- Single argument buffer descriptor
- Array of argument buffer descriptors
Other cases are unimplemented for now since they are extremely painful
to unroll.
The standard `matrix` type in MSL lacked a constructor in the
`threadgroup` AS. This means that it was impossible to declare a
`threadgroup` variable that contains a matrix. This appears to have been
an oversight that was corrected in macOS 13/Xcode 14 beta 4. This
workaround continues to be required, however, for older systems.
To avoid changing interfaces unnecessarily (which shouldn't be a problem
regardless because the old and new types take up the same amount of
storage), only do this for structs if the struct is positively
identified as being used for workgroup storage.
I'm entirely aware this is inconsistent with the way packed matrices are
handled. One of them should be changed to match the other. Not sure
which one.
Fixes 23 CTS tests under `dEQP-VK.memory_model.shared`.
Since `bool` is a logical type, it cannot be used in uniform or storage
buffers. Therefore, replacing it in structures should not change the
shader interface.
We leave it alone for builtins. (FIXME: Should we also leave it for
I/O varyings?)
Fixes 24 CTS tests under `dEQP-VK.memory_model.shared`.
- Assign ulongn physical type to buffer pointers in short arrays
when array stride is larger than pointer size.
- Support GL_EXT_buffer_reference_uvec2 casting
buffer reference pointers to and from uvec2 values.
- When packing structs, include structs inside physical buffers.
- Update mechanism for traversing pointer arrays when calculating type sizes.
- Added unit test shaders.
- Determine sizing and alignments of pointers to types as
distinct from the size and alignment of the types themselves.
- Declare all buffer pointers in the MSL device address space.
- Support struct pointer recursion, where structs can
contain pointers to themselves or to a parent struct.
- Add SPIRType::was_forward_referenced to track if a type was forward
referenced, to help emit MSL structs in the correct dependency order.
- Handle pointers to pointers that are not just arrays of arrays.
