I cannot find any evidence that this does not actually work.
The original case here was from Epic's PR series in 2019, but I cannot see why it doesn't work.
It might have been a bug in a very old compiler at some point.
Argument buffers can contain multiple runtime arrays if they have fixed
lengths as specified by the binding API. Regression error had assumed each
runtime array is in separate argument buffer with undefined array length.
- Add CompilerMSL::is_var_runtime_size_array() to include test for
setting of array length via CompilerMSL::add_msl_resource_binding().
- Fixed unrelated test case MSL compile syntax failure when acceleration
structure is the first entry point function argument (unrelated).
Handling native array types is not really feasible since we need to fuse
the variable declaration with the type declaration.
This is feasible in something like variable_decl, but for plain SSA
pointers, this breaks down.
If we have emitted block IO lowering at the end of vertex shader, we
will end up using the wrong name. Forcing a v_ prefix does not solve any
actual problems since the intentifier already has to be valid.
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.
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.)
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.
MSL inherits the behavior of C where arithmetic on small types are
implicitly converted to int. SPIR-V does not have this behavior, so make
sure that arithmetic results are handled correctly.
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.
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.*`
When storing to local variable (eg. OpCopyLogical), the
default device address space used during casts is illegal.
Determine correct address space based on variable type.
- Add CompilerMSL::emit_binary_ptr_op() and to_ptr_expression()
to emit binary pointer op. Compare matrix addresses without automatic
transpose() conversion, to avoid error taking address of temporary copy.
- Add Compiler::add_active_interface_variable() to also track active
interface vars in the entry point for SPIR-V 1.4 and above.
- For OpPtrAccessChain that ends in array element, use Element
as offset to existing index, otherwise it will access into
array dimension that doesn't exist.
- Dereference pointer function call arguments. Ultimately, this
dereferencing is actually backwards, and in future, we should aim
to properly support passing pointer variables between functions,
but such a refactoring was beyond the scope here.
- Use [] to declare array of pointers, as array<T*> is not supported in MSL.
- Add unit test shaders.
Speculate that we can modify the SSA value in-place. As long as it is
not used after the modify, this is fine.
Also need to make sure we don't attempt to RMW something that is
impossible to modify.
Just like we try to fixup struct names for block types, inner structs
can be "anonymous" structs. HLSL codegen from DXC tends to emit this,
and emitting dummy struct names tends to break GL linkage on some
drivers.
This allows two variables of the same struct type to be flattened
into the same interface struct without a member name conflict.
Add shaders-msl/frag/in_block_with_multiple_structs_of_same_type.frag
unit test shader to demonstrate this.
