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.
When we force recompile, the old var.self name we used as a fallback
name might have been disturbed, so we should recover certain names back
to their original form in case we are forced to take a recompile to make
the naming algorithm more deterministic.
There's no need to do so, since these are not stage-out structs being
returned, but regular structures being written to a buffer. This also
neatly avoids issues writing to composite (e.g. arrayed) per-patch
outputs from a tessellation control shader.
These are transpiled to kernel functions that write the output of the
shader to three buffers: one for per-vertex varyings, one for per-patch
varyings, and one for the tessellation levels. This structure is
mandated by the way Metal works, where the tessellation factors are
supplied to the draw method in their own buffer, while the per-patch and
per-vertex varyings are supplied as though they were vertex attributes;
since they have different step rates, they must be in separate buffers.
The kernel is expected to be run in a workgroup whose size is the
greater of the number of input or output control points. It uses Metal's
support for vertex-style stage input to a compute shader to get the
input values; therefore, at least one instance must run per input point.
Meanwhile, Vulkan mandates that it run at least once per output point.
Overrunning the output array is a concern, but any values written should
either be discarded or overwritten by subsequent patches. I'm probably
going to put some slop space in the buffer when I integrate this into
MoltenVK to be on the safe side.
This is necessary to deal with indirect draws, where the draw parameters
are given in a buffer instead of passed by the CPU. For normal draws,
the draw parameters are set with Metal's `setVertexBytes:` method.
This undoes the change to add the vertex count to the aux buffer,
rendering that entire discussion largely moot. Oh well. It was a
discussion that needed to happen anyway.
Storage was in place already, so mostly just dealing with bitcasts and
constants.
Simplies some of the bitcasting logic, and this exposed some bugs in the
implementation. Refactor to use correct width integers with explicit bitcast opcodes.
Structs are aligned as you would expect in MSL (maximum member
alignment), and it is not minimum 16 bytes like in std140.
Also rename the dummy "pad" members to a reserved naming scheme.
Apparently we didn't use those yet. MSL seems to be able to alias struct
types and variable types to a degree, so that's why it has escaped
testing until now.
In the past, SPIRV-Cross threw an error in this case because it couldn't
work out which swizzle from the auxiliary buffer needs to be passed.
Now, we pass the swizzle around with the texture object, like a combined
image-sampler and its associated sampler.
If not enough components are provided in the shader,
the shader MSL compiler throws an error rather than make components
undefined. This hurts portability, so we need to add explicit padding
here.
MSL does not support value semantics for arrays (sigh), so we need to
force constant references and deal with copies if we have a different
address space than what we end up guessing.
This is a fairly fundamental change on how IDs are handled.
It serves many purposes:
- Improve performance. We only need to iterate over IDs which are
relevant at any one time.
- Makes sure we iterate through IDs in SPIR-V module declaration order
rather than ID space. IDs don't have to be monotonically increasing,
which was an assumption SPIRV-Cross used to have. It has apparently
never been a problem until now.
- Support LUTs of structs. We do this by interleaving declaration of
constants and struct types in SPIR-V module order.
To support this, the ParsedIR interface needed to change slightly.
Before setting any ID with variant_set<T> we let ParsedIR know
that an ID with a specific type has been added. The surface for change
should be minimal.
ParsedIR will maintain a per-type list of IDs which the cross-compiler
will need to consider for later.
Instead of looping over ir.ids[] (which can be extremely large), we loop
over types now, using:
ir.for_each_typed_id<SPIRVariable>([&](uint32_t id, SPIRVariable &var) {
handle_variable(var);
});
Now we make sure that we're never looking at irrelevant types.
This allows shaders to declare and use pointer-type variables. Pointers
may be loaded and stored, be the result of an `OpSelect`, be passed to
and returned from functions, and even be passed as inputs to the `OpPhi`
instruction. All types of pointers may be used as variable pointers.
Variable pointers to storage buffers and workgroup memory may even be
loaded from and stored to, as though they were ordinary variables. In
addition, this enables using an interior pointer to an array as though
it were an array pointer itself using the `OpPtrAccessChain`
instruction.
This is a rather large and involved change, mostly because this is
somewhat complicated with a lot of moving parts. It's a wonder
SPIRV-Cross's output is largely unchanged. Indeed, many of these changes
are to accomplish exactly that! Perhaps the largest source of changes
was the violation of the assumption that, when emitting types, the
pointer type didn't matter.
One of the test cases added by the change doesn't optimize very well;
the output of `spirv-opt` here is invalid SPIR-V. I need to file a bug
with SPIRV-Tools about this.
I wanted to test that variable pointers to images worked too, but I
couldn't figure out how to propagate the access qualifier properly--in
MSL, it's part of the type, so getting this right is important. I've
punted on that for now.
Just like OpAccessChain we need to make use of the meta information
available to use from access_chain_internal as we can extract a packed
vector or transposed vector from a composite, not just memory load.
A block name cannot alias with any name in its own scope,
and it cannot alias with any other "global" name.
To solve this, we need to complicate the name cache updates a little bit
where we have a "primary" namespace and "secondary" namespace.
This is required to avoid relying on complex sub-expression elimination
in compilers, and generates cleaner code.
The problem case is if a complex expression is used in an access chain,
like:
Composite comp = buffer[texture(...)];
vec4 a = comp.a + comp.b + comp.c;
Before, we did not have common subexpression tracking for
OpLoad/OpAccessChain, so we easily ended up with code like:
vec4 a = buffer[texture(...)].a + buffer[texture(...)].b + buffer[texture(...)].c;
A good compiler will optimize this, but we should not rely on it, and
forcing texture(...) to a temporary also looks better.
The solution is to add a vector "implied_expression_reads", which works
similarly to expression_dependencies. We also need an extra mechanism in
to_expression which lets us skip expression read checking and do it
later. E.g. for expr -> access chain -> load, we should only trigger
a read of expr when using the loaded expression.
