microsoft / microsoft/DirectXShaderCompiler
[SPIR-V] SPV_EXT_descriptor_heap Direct-subscript buffer return bypasses heap alias rejection diagnostic
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- Dominant language
- C++
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Description
Description
In doReturnStmt (SpirvEmitter.cpp), return (StructuredBuffer<T>)ResourceDescriptorHeap[i]; takes the direct-subscript branch which skips the alias-return diagnostic. This path attempts to carry an OpBufferPointerEXT value across OpReturnValue, which is unsupported cross-function pointer propagation. No error is emitted and the resulting SPIR-V is invalid.
Fix
In the direct-subscript return path, check whether resourceType is a buffer-like type and emit the same "heap buffer alias cannot be returned" diagnostic that the alias path emits, then terminate the block with an undef return value.
References
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Research direction
Start in SpirvEmitter.cpp at doReturnStmt and trace the direct-subscript return branch for ResourceDescriptorHeap[i]. Compare it with the existing alias-return diagnostic path and verify the buffer-like resource case. Done means the same heap buffer alias diagnostic is emitted and the block returns an undef value instead of propagating OpBufferPointerEXT across OpReturnValue.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- cpp
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 2/5
- Estimated time
- 1-3 hours
- Activity status
- Active
- Clarity
- Clearly specified
- Newbie friendliness
- 75/100