This was straightforward to implement in GLSL. The
`ShadingRateInterlockOrderedEXT` and `ShadingRateInterlockUnorderedEXT`
modes aren't implemented yet, because we don't support
`SPV_NV_shading_rate` or `SPV_EXT_fragment_invocation_density` yet.
HLSL and MSL were more interesting. They don't support this directly,
but they do support marking resources as "rasterizer ordered," which
does roughly the same thing. So this implementation scans all accesses
inside the critical section and marks all storage resources found
therein as rasterizer ordered. They also don't support the fine-grained
controls on pixel- vs. sample-level interlock and disabling ordering
guarantees that GLSL and SPIR-V do, but that's OK. "Unordered" here
merely means the order is undefined; that it just so happens to be the
same as rasterizer order is immaterial. As for pixel- vs. sample-level
interlock, Vulkan explicitly states:
> With sample shading enabled, [the `PixelInterlockOrderedEXT` and
> `PixelInterlockUnorderedEXT`] execution modes are treated like
> `SampleInterlockOrderedEXT` or `SampleInterlockUnorderedEXT`
> respectively.
and:
> If [the `SampleInterlockOrderedEXT` or `SampleInterlockUnorderedEXT`]
> execution modes are used in single-sample mode they are treated like
> `PixelInterlockOrderedEXT` or `PixelInterlockUnorderedEXT`
> respectively.
So this will DTRT for MoltenVK and gfx-rs, at least.
MSL additionally supports multiple raster order groups; resources that
are not accessed together can be placed in different ROGs to allow them
to be synchronized separately. A more sophisticated analysis might be
able to place resources optimally, but that's outside the scope of this
change. For now, we assign all resources to group 0, which should do for
our purposes.
`glslang` doesn't support the `RasterizerOrdered` UAVs this
implementation produces for HLSL, so the test case needs `fxc.exe`.
It also insists on GLSL 4.50 for `GL_ARB_fragment_shader_interlock`,
even though the spec says it needs either 4.20 or
`GL_ARB_shader_image_load_store`; and it doesn't support the
`GL_NV_fragment_shader_interlock` extension at all. So I haven't been
able to test those code paths.
Fixes#1002.
This change introduces functions and in one case, a class, to support
the `VK_KHR_sampler_ycbcr_conversion` extension. Except in the case of
GBGR8 and BGRG8 formats, for which Metal natively supports implicit
chroma reconstruction, we're on our own here. We have to do everything
ourselves. Much of the complexity comes from the need to support
multiple planes, which must now be passed to functions that use the
corresponding combined image-samplers. The rest is from the actual
Y'CbCr conversion itself, which requires additional post-processing of
the sample retrieved from the image.
Passing sampled images to a function was a particular problem. To
support this, I've added a new class which is emitted to MSL shaders
that pass sampled images with Y'CbCr conversions attached around. It
can handle sampled images with or without Y'CbCr conversion. This is an
awful abomination that should not exist, but I'm worried that there's
some shader out there which does this. This support requires Metal 2.0
to work properly, because it uses default-constructed texture objects,
which were only added in MSL 2. I'm not even going to get into arrays of
combined image-samplers--that's a whole other can of worms. They are
deliberately unsupported in this change.
I've taken the liberty of refactoring the support for texture swizzling
while I'm at it. It's now treated as a post-processing step similar to
Y'CbCr conversion. I'd like to think this is cleaner than having
everything in `to_function_name()`/`to_function_args()`. It still looks
really hairy, though. I did, however, get rid of the explicit type
arguments to `spvGatherSwizzle()`/`spvGatherCompareSwizzle()`.
Update the C API. In addition to supporting this new functionality, add
some compiler options that I added in previous changes, but for which I
neglected to update the C API.
ESSL does not support `GL_ARB_post_depth_coverage`. There, we must use
`GL_EXT_post_depth_coverage`. I've added this as a fallback for desktop
as well.
Note that `GL_EXT_post_depth_coverage` also requires the fragment shader
to set `early_fragment_tests` explicitly, while
`GL_ARB_post_depth_coverage` does not. It doesn't really matter either
way, since `SPV_KHR_post_depth_coverage` *also* requires both execution
modes to be explicitly set.
When merging combined image samplers, we only looked at sampler, but DXC
emits RelaxedPrecision only for texture. Does not hurt to check for more
things.
Inner scope can still dominate here, so we need to be conservative when
we observe switch blocks specifically. Normal selection merges cannot
merge from multiple paths.
This command allows the caller to set the base value of
`BuiltInWorkgroupId`, and thus of `BuiltInGlobalInvocationId`. Metal
provides no direct support for this... but it does provide a builtin,
`[[grid_origin]]`, normally used to pass the base values for the stage
input region, which we will now abuse to pass the dispatch base and
avoid burning a buffer binding.
`[[grid_origin]]`, as part of Metal's support for compute stage input,
requires MSL 1.2. For 1.0 and 1.1, we're forced to provide a buffer.
(Curiously, this builtin was undocumented until the MSL 2.2 release. Go
figure.)
This is not necessary, as we must emit an invalidating store before we
potentially consume an invalid expression. In fact, we're a bit
conservative here in this case for example:
int tmp = variable;
if (...)
{
variable = 10;
}
else
{
// Consuming tmp here is fine, but it was
// invalidated while emitting other branch.
// Technically, we need to study if there is an invalidating store
// in the CFG between the loading block and this block, and the other
// branch will not be a part of that analysis.
int tmp2 = tmp * tmp;
}
Fixing this case means complex CFG traversal *everywhere*, and it feels like overkill.
Fixing this exposed a bug with access chains, so fix a bug where expression dependencies were not
inherited properly in access chains. Access chains are now considered forwarded if there
is at least one dependency which is also forwarded.
This subtle bug removed any expression validation for trivially swizzled
variables. Make usage suppression a more explicit concept rather than
just hacking off forwarded_temporaries.
There is some fallout here with loop generation since our expression
invalidation is currently a bit too naive to handle loops properly.
The forwarding bug masked this problem until now.
If part of the loop condition is also used in the body, we end up
reading an invalid expression, which in turn forces a temporary to be
generated in the condition block, not good. We'll need to be smarter
here ...
If this is computed *before* a `demote`, but used *after*, forwarding it
will produce the wrong value. This does make for uglier shaders, but
it's necessary right now to ensure correctness.
I needed to use an assembly shader to produce the test for this.
`spirv-opt` is not smart enough (or too smart?) to eliminate the
variable that would be used in GLSL to express this.
This extension provides a new operation which causes a fragment to be
discarded without terminating the fragment shader invocation. The
invocation for the discarded fragment becomes a helper invocation, so
that derivatives will remain defined. The old `HelperInvocation` builtin
becomes undefined when this occurs, so a second new instruction queries
the current helper invocation status.
This is only fully supported for GLSL. HLSL doesn't support the
`IsHelperInvocation` operation and MSL doesn't support the
`DemoteToHelperInvocation` op.
Fixes#1052.
Make sure to test everything with scalar as well to catch any weird edge
cases.
Not all opcodes are covered here, just the arithmetic ones. FP64 packing
is also ignored.
This provides a few functions normally available in OpenCL to the SPIR-V
shader environment. These functions happen to be available in Metal as
well.
No GLSL, unfortunately. Intel has yet to publish a
`GL_INTEL_shader_integer_functions2` spec.
Fix fallout from changes.
There's a bug in glslang that prevents `float16_t`, `[u]int16_t`, and
`[u]int8_t` constants from adding the corresponding SPIR-V capabilities.
SPIRV-Tools, meanwhile, tightened validation so that these constants are
only valid if the corresponding `Float16`, `Int16`, and `Int8` caps are
on. This affects the `16bit-constants.frag` test for GLSL and MSL.
The only piece added by this extension is the `DeviceIndex` builtin,
which tells the shader which device in a grouped logical device it is
running on.
Metal's pipeline state objects are owned by the `MTLDevice` that created
them. Since Metal doesn't support logical grouping of devices the way
Vulkan does, we'll thus have to create a pipeline state for each device
in a grouped logical device. The upcoming peer group support in Metal 3
will not change this. For this reason, for Metal, the device index is
supplied as a constant at pipeline compile time.
There's an interaction between `VK_KHR_device_group` and
`VK_KHR_multiview` in the
`VK_PIPELINE_CREATE_VIEW_INDEX_FROM_DEVICE_INDEX_BIT`, which defines the
view index to be the same as the device index. The new
`view_index_from_device_index` MSL option supports this functionality.
Using the `PostDepthCoverage` mode specifies that the `gl_SampleMaskIn`
variable is to contain the computed coverage mask following the early
fragment tests, which this mode requires and implicitly enables.
Note that unlike Vulkan and OpenGL, Metal places this on the sample mask
input itself, and furthermore does *not* implicitly enable early
fragment testing. If it isn't enabled explicitly with an
`[[early_fragment_tests]]` attribute, the compiler will error out. So we
have to enable that mode explicitly if `PostDepthCoverage` is enabled
but `EarlyFragmentTests` isn't.
For Metal, only iOS supports this; for some reason, Apple has yet to
implement it on macOS, even though many desktop cards support it.
This maps them to their MSL equivalents. I've mapped `Coherent` to
`volatile` since MSL doesn't have anything weaker than `volatile` but
stronger than nothing.
As part of this, I had to remove the implicit `volatile` added for
atomic operation casts. If the buffer is already `coherent` or
`volatile`, then we would add a second `volatile`, which would be
redundant. I think this is OK even when the buffer *doesn't* have
`coherent`: `T *` is implicitly convertible to `volatile T *`, but not
vice-versa. It seems to compile OK at any rate. (Note that the
non-`volatile` overloads of the atomic functions documented in the spec
aren't present in the MSL 2.2 stdlib headers.)
`restrict` is tricky, because in MSL, as in C++, it needs to go *after*
the asterisk or ampersand for the pointer type it's modifying.
Another issue is that, in the `Simple`, `GLSL450`, and `Vulkan` memory
models, `Restrict` is the default (i.e. does not need to be specified);
but MSL likely follows the `OpenCL` model where `Aliased` is the
default. We probably need to implicitly set either `Restrict` or
`Aliased` depending on the module's declared memory model.
The old method of using a different unpacked matrix type doesn't work
for scalar alignment. It certainly wouldn't have any effect for a square
matrix, since the number of columns and rows are the same. So now we'll
store them as arrays of packed vectors.
Relaxed block layout relaxed the restrictions on vector alignment,
allowing them to be aligned on scalar boundaries. Scalar block layout
relaxes this further, allowing *any* member to be aligned on a scalar
boundary. The requirement that a vector not improperly straddle a
16-byte boundary is also relaxed.
I've also added a test showing that `std430` layout works with UBOs.
I'm troubled by the dual meaning of the `Packed` extended decoration. In
some instances (struct, `float[]`, and `vec2[]` members), it actually
means the exact opposite, that the member needs extra padding. This is
especially problematic for `vec2[]`, because now we need to distinguish
the two cases by checking the array stride. I wonder if this should
actually be split into two decorations.
There is a case where we can deduce a for/while loop, but the continue
block is actually very painful to deal with, so handle that case as
well. Removes an exceptional case.
MSL prior to 2.2 doesn't support these natively in any stage but
compute. But, we can (assuming no threads were terminated prematurely)
get their values with some creative uses of the
`simd_prefix_exclusive_sum()` and `simd_sum()` functions.
Also, fix a missing `to_expression()` with `BuiltInSubgroupEqMask`.
For KhronosGroup/MoltenVK#629.
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.
In the bizarre case where the ID of a loaded opaque type aliased with a
literal which was used as part of another texturing instruction, we
could end up with a case where domination analysis assumed the loaded
opaque type needed to be moved to a different scope.
Fix the issue by never doing dominance analysis for opaque temporaries,
and be more robust when analyzing texturing instructions.
Also make sure reflection output is deterministic.
This patch slightly alterered output for some unknown reason, but it came from an
unordered_map, so it's fine.
This is intended to be used to support `VK_KHR_maintenance2`'s
tessellation domain origin feature. If `tess_domain_origin_lower_left`
is `true`, the `v` coordinate will be inverted with respect to the
domain. Additionally, in `Triangles` mode, the `v` and `w` coordinates
will be swapped. This is because the winding order is interpreted
differently in lower-left mode.
These are mapped to Metal's post-tessellation vertex functions. The
semantic difference is much less here, so this change should be simpler
than the previous one. There are still some hairy parts, though.
In MSL, the array of control point data is represented by a special
type, `patch_control_point<T>`, where `T` is a valid stage-input type.
This object must be embedded inside the patch-level stage input. For
this reason, I've added a new type to the type system to represent this.
On Mac, the number of input control points to the function must be
specified in the `patch()` attribute. This is optional on iOS.
SPIRV-Cross takes this from the `OutputVertices` execution mode; the
intent is that if it's not set in the shader itself, MoltenVK will set
it from the tessellation control shader. If you're translating these
offline, you'll have to update the control point count manually, since
this number must match the number that is passed to the
`drawPatches:...` family of methods.
Fixes#120.
This should fix a whole host of issues related to structs in the `Input`
class in a tessellation control shader.
Also, use pointer arithmetic instead of dereferencing the `ops` array.
This is critical in case we wind up stepping beyond the bounds of the
array.
