microsoft / microsoft/DirectXShaderCompiler
[SPIRV] Invalid OpCompositeConstruct when aggregate-initializing struct with resource member
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Description
When compiling HLSL that uses brace initialization to construct a struct containing a resource member, DXC's SPIRV backend generates invalid SPIR-V:
fatal error: generated SPIR-V is invalid: Expected Constituent type to be equal to the corresponding member type of Result Type struct %15 = OpCompositeConstruct %ResHolder_0 %Out
Repro:
RWByteAddressBuffer Out : register(u0);
struct ResHolder { RWByteAddressBuffer buf; };
[numthreads(1,1,1)]
void main() {
ResHolder h = {Out};
h.buf.Store(0, 42);
}
Command:
dxc.exe -spirv -fspv-target-env=vulkan1.3 -T cs_6_0 -Fo out.spv repro.hlsl
DXC DXIL compiles and runs this correctly. DXC version: main (built from source).
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
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- Open a pull request that references the issue number.
Research direction
Start by building DXC from source and running the provided HLSL repro with the shown -spirv command. Inspect the SPIR-V generation and validation for aggregate initialization of a struct containing RWByteAddressBuffer. Done means the repro produces valid SPIR-V without the constituent-type error and preserves the resource member behavior.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- cpp
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Quiet
- Clarity
- Mostly clear
- Newbie friendliness
- 48/100