This is needed to support `VK_KHR_multiview`, which is in turn needed
for Vulkan 1.1 support. Unfortunately, Metal provides no native support
for this, and Apple is once again less than forthcoming, so we have to
implement it all ourselves.
Tessellation and geometry shaders are deliberately unsupported for now.
The problem is that the current implementation encodes the `ViewIndex`
as part of the `InstanceIndex`, which in the SPIR-V environment at least
only exists in the vertex shader. So we need to work out a way to pass
the view index along to the later stages.
This implementation runs vertex shaders for all views up to the highest
bit set in the view mask, even those whose bits are clear. The fragments
for the inactive views are then discarded. Avoiding this is difficult:
calculating the view indices becomes far more complicated if we can only
run for those views which are set in the mask.
This is quite complex since we cannot flush Phi inside the case labels,
we have to do it outside by emitting a lot of manual branches ourselves.
This should be extremely rare, but we need to handle this case.
We used to use the Binding decoration for this, but this method is
hopelessly broken. If no explicit MSL resource remapping exists, we
remap automatically in a manner which should always "just work".
If we compile multiple times due to forced_recompile, we had
deferred_declaration = true while emitting function prototypes which
broke an assumption. Fix this by clearing out stale state before leaving
a function.
This is rather shaky, but we don't have many choices here except add a
lot of awkward and unintuitive options. Try to deduce this from OpSource
and fallback to heuristic.
There is a risk that we try to preserve a loop variable through multiple
iterations, even though the dominating block is inside a loop.
Fix this by analyzing if a block starts off by writing to a variable. In
that case, there cannot be any preservation going on. If we don't, pretend the
loop header is reading the variable, which moves the variable to an
appropriate scope.
In multiple-entry-point modules, we declared builtin inputs which were
not supposed to be used for that entry point.
Fix this, by being more strict when checking which builtins to emit.
This gets rather complicated because MSL does not support OpArrayLength
natively. We need to pass down a buffer which contains buffer sizes, and
we compute the array length on-demand.
Support both discrete descriptors as well as argument buffers.
MSL generally emits the aliases, which means we cannot always place the
master type first, unlike GLSL and HLSL. The logic fix is just to
reorder after we have tagged types with packing information, rather than
doing it in the parser fixup.
Change aux buffer to swizzle buffer.
There is no good reason to expand the aux buffer, so name it
appropriately.
Make the code cleaner by emitting a straight pointer to uint rather than
a dummy struct which only contains a single unsized array member anyways.
This will also end up being very similar to how we implement swizzle
buffers for argument buffers.
Do not use implied binding if it overflows int32_t.
Some support for subgroups is present starting in Metal 2.0 on both iOS
and macOS. macOS gains more complete support in 10.14 (Metal 2.1).
Some restrictions are present. On iOS and on macOS 10.13, the
implementation of `OpGroupNonUniformElect` is incorrect: if thread 0 has
already terminated or is not executing a conditional branch, the first
thread that *is* will falsely believe itself not to be. Unfortunately,
this operation is part of the "basic" feature set; without it, subgroups
cannot be supported at all.
The `SubgroupSize` and `SubgroupLocalInvocationId` builtins are only
available in compute shaders (and, by extension, tessellation control
shaders), despite SPIR-V making them available in all stages. This
limits the usefulness of some of the subgroup operations in fragment
shaders.
Although Metal on macOS supports some clustered, inclusive, and
exclusive operations, it does not support them all. In particular,
inclusive and exclusive min, max, and, or, and xor; as well as cluster
sizes other than 4 are not supported. If this becomes a problem, they
could be emulated, but at a significant performance cost due to the need
for non-uniform operations.
MSL does not seem to have a qualifier for this, but HLSL SM 5.1 does.
glslangValidator for HLSL does not support this, so skip any validation,
but it passes in FXC.
Buffer objects can contain arbitrary pointers to blocks.
We can also implement ConvertPtrToU and ConvertUToPtr.
The latter can cast a uint64_t to any type as it pleases,
so we will need to generate fake buffer reference blocks to be able to
cast the type.
We made the mistake of registering a dependency on the atomic variable
even if the atomic result was forced to a temporary. There is no need to
register reads from atomic variables like this as we always force atomic
results to a temporary and argument read/writes do not need to be
tracked.
Atomics are not supported on images or texture_buffers in MSL.
Properly throw an error if OpImageTexelPointer is used (since it can
only be used for atomic operations anyways).
* origin/master:
Support running {,update_}test_shader.sh with CMake builds.
Don't apply vertex attribute remapping other non-vertex or non-input interface blocks
Force complex loop in certain rare access chain scenarios.
Fix guard around [[noreturn]].
Deal with mismatched signs in S/U/F conversion opcodes.
Workaround lack of lvalue/rvalue operator overload on MSVC 2013.
Support direct conversions to std::vector from SmallVector.
Fix some minor copy constructor issues in Variant.
Make sure ids_for_types are moved correctly in move operator.
Run format_all.sh.
Refactor out error handling and containers to new headers.
Do not use SmallVector as input type in public interfaces.
Fix various bugs found in testing.
Explicitly implement move operators for ParsedIR.
Try another MSVC 2013 workaround.
Implement edge cases in insert/end and add a simple test case.
Fix GCC 4.x warnings.
Workaround lack of alignas on MSVC 2013.
Reduce pressure on global allocation.
CLI: Make --iterations more useful.
If we generate an access chain in a loop body, and it is consumed in the
loop continue block, we have a problem because we cannot emit a
temporary here holding the access chain reference. Force a complex loop
body to workaround this exceptionally rare case.
We cannot deduce if OpLoad needs ArrayCopy templates early since it's
heavily context dependent, and we might only know on 3rd iteration of
the compile loop.
We had a bug where error conditions in DoWhileLoop emit path would not
detect that statements were being emitted due to the masking behavior
which happens when force_recompile is true. Fix this.
Also, refactor force_recompile into member functions so we can properly
break on any situation where this is set, without having to rely on
watchpoints in debuggers.
Avoids ugly warnings on nearly every compute shader.
We could do analysis to detect whether we need to emit this constant,
but it's a bit tedious to figure out if an OpConstantComponent is
actually used by opcodes, so just make it simple.
-1 (0xffffffff) literal means the component should be undefined.
Since we cannot express undefined directly, just use a 0 literal in the
appropriate type.
We have an edge case where the array is declared with a concrete size,
but in GLSL we must emit an unsized array, which breaks array copies.
Deal explicitly with this.
Return after loading the input control point array if there are more
input points than output points, and this was one of the helper
invocations spun off to load the input points. I was hesitant to do this
initially, since the MSL spec has this to say about barriers:
> The `threadgroup_barrier` (or `simdgroup_barrier`) function must be
> encountered by all threads in a threadgroup (or SIMD-group) executing
> the kernel.
That is, if any thread executes the barrier, then all threads must
execute it, or the barrier'd invocations will hang. But, the key words
here seem to be "executing the kernel;" inactive invocations, those that
have already returned, need not encounter the barrier to prevent hangs.
Indeed, I've encountered no problems from doing this, at least on my
hardware. This also fixes a few CTS tests that were failing due to
execution ordering; apparently, my assumption that the later, invalid
data written by the helpers would get overwritten was wrong.
The tessellation levels in Metal are stored as a densely-packed array of
half-precision floating point values. But, stage-in attributes in Metal
have to have offsets and strides aligned to a multiple of four, so we
can't add them individually. Luckily for us, the arrays have lengths
less than 4. So, let's use vectors for them!
Triangles get a single attribute with a `float4`, where the outer levels
are in `.xyz` and the inner levels are in `.w`. The arrays are unpacked
as though we had added the elements individually. Quads get two: a
`float4` with the outer levels and a `float2` with the inner levels.
Further, since vectors can be indexed as arrays, there's no need to
unpack them in this case.
This also saves on precious vertex attributes. Before, we were using up
to 6 of them. Now we need two at most.
In SPIR-V, there are always two inner levels and four outer levels, even
if the input patch isn't a quad patch. But in MSL, due to requirements
imposed by Metal, only one inner level and three outer levels exist when
the input patch is a triangle patch. We must explicitly ignore any write
to the nonexistent second inner and fourth outer levels in this case.
