[HLSL] Add descriptor table metadata parsing #142492
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joaosaffran
requested review from
bogner,
inbelic and
alsepkow
and removed request for
alsepkow,
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| return Flags == FlagT::DESCRIPTORS_VOLATILE; | ||
| } | ||
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| // The data-specific flags are mutually exclusive. |
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the descriptor flags are also mutually exclusive. Do we want an explicit check for this? It seems like it is covered below. Maybe it is good for clarity?
| DESCRIPTOR_RANGE(1, UAV) | ||
| DESCRIPTOR_RANGE(2, CBV) | ||
| DESCRIPTOR_RANGE(3, Sampler) | ||
| DESCRIPTOR_RANGE(4, NONE) |
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Why do we have a value for NONE here? A value of 4 in the metadata would certainly be invalid, and this appears to be unused.
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This came as a request from another PR, where Finn mentioned those values are useful in the frontend, since we are planning on sharing this, I've added those back.
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Do you have a link to that conversation handy? I'd like to see how NONE would be used here...
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Here is an example use case of NONE in the frontend:
.But that discussion was in the context of flags, I will remove this one from here, since it doesn't seem to match the pattern of other NONE values
| .Default(-1u); | ||
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| if (Range.RangeType == -1u) |
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Clearer to use ~0U rather than -1U, and this way avoids some warnings from MSVC in any case.
| @@ -174,6 +174,94 @@ static bool parseRootDescriptors(LLVMContext *Ctx, | |||
| return false; | |||
| } | |||
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| static bool parseDescriptorRange(LLVMContext *Ctx, | |||
| mcdxbc::RootSignatureDesc &RSD, | |||
| if (Version == 1) { | ||
| if (IsSampler) | ||
| return Flags == FlagT::NONE; | ||
| return Flags == FlagT::DESCRIPTORS_VOLATILE; | ||
| } |
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These values are still incorrect. As I mentioned in #142492 (comment) samplers can only have DESCRIPTORS_VOLATILE, and otherwise this needs to be DATA_VOLATILE.
Also, please add a test for this - we should be catching that this is obviously wrong.
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There is some confusion in the spec, there are 2 sections saying different values are valid for this field. Reached in private to discuss this.
I'll add the test.
| // When no descriptor flag is set, any data flag is allowed. | ||
| return (Flags & ~DataFlags) == FlagT::NONE; |
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This is not correct. Samplers can never have the DATA_* flags set.
| OS << indent(2) << "- Range Type: " << Range.RangeType << "\n"; | ||
| OS << indent(4) << "Register Space: " << Range.RegisterSpace << "\n"; | ||
| OS << indent(4) | ||
| << "Base Shader Register: " << Range.BaseShaderRegister << "\n"; | ||
| OS << indent(4) << "Num Descriptors: " << Range.NumDescriptors | ||
| << "\n"; | ||
| OS << indent(4) << "Offset In Descriptors From Table Start: " | ||
| << Range.OffsetInDescriptorsFromTableStart << "\n"; | ||
| if (RS.Version > 1) | ||
| OS << indent(4) << "Flags: " << Range.Flags << "\n"; |
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Maybe it's just me, but I find using the indent() function with a small constant to be quite a bit less clear than just putting the spaces in the strings. Consider:
OS << " - Range Type: " << Range.RangeType << "\n"
<< " Register Space: " << Range.RegisterSpace << "\n"
<< " Base Shader Register: " << Range.BaseShaderRegister << "\n"
<< " Num Descriptors: " << Range.NumDescriptors << "\n"
<< " Offset In Descriptors From Table Start: "
<< Range.OffsetInDescriptorsFromTableStart << "\n";
if (RS.Version > 1)
OS << " Flags: " << Range.Flags << "\n";Here, you can see how the strings line up just by looking at them. Though admittedly it can get a bit messier with longer lines. IMO indent() is mostly useful when the indentation varies depending on context, or is large enough that just writing it out makes things less readable.
Closes: #126640