HLSL is very fussy about fallthrough in switch blocks, so promote
Unreachable blocks to breaks if they are inside a switch construct.
Some false positives are possible in weird multi-break scenarios, but
this is benign.
It is possible for a shader to declare two plain struct types which
simply share the same OpName without there being an implicit
value/buffer alias relationship.
For to_member_name(), make sure to use the type alias master when
resolving member names. The member name may be different in a type alias
master if the SPIR-V is being intentionally difficult.
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.
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.
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.
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.
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.
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.
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.
- Add new Windows support
- Use CMake/CTest instead of Make + shell scripts
- Use --parallel in CTest
- Fix CTest on Windows
- Cleanups in test_shaders.py
- Force specific commit for SPIRV-Headers
- Fix Inf/NaN odd-ball case by moving to ASM
