Handle uninitialized resources in structs #9151
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Fixes shader-slang#8443 In order to support some legacy shaders, we will allow zero-initialization of structs that contain resource types as fields. The resource variables get initialized to a Poison value. We also issue a diagnostic warning. The expectation here is that (a) the correct value will be assigned in SSA, or (b) if there's a branch scope where it remains initialized to Poison, the value will subsequently not be used. (The latter case is the one that we needed to implement this change for.)
jhelferty-nv
commented
Nov 27, 2025
| getSink()->diagnose( | ||
| fromInitializerListExpr->loc, | ||
| Diagnostics::cannotUseInitializerListForResourceType, | ||
| toType); |
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So the one downside here is that instead of the one warning, we end up with two warnings, because a later chunk of code notices that the source is uninitialized:
tests/spirv/zero-init-tex2d-field.slang(27): warning 30506: cannot use initializer list for resource type 'Texture2D<vector<float,4>>'
S s = (S)0;
^
tests/spirv/zero-init-tex2d-field.slang(27): warning 41016: use of uninitialized variable ''
S s = (S)0;
^
The variant of tests/diagnostics/uninitialized-resource-type.slang that uses arrays was generating duplicate diagnostics without tracking back the source location. This change fixes that. Also cleans up the diagnostic message content.
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Fixes #8443
In order to support some legacy shaders, we will allow zero-initialization of structs that contain resource types as fields. The resource variables get initialized to a Poison value. We also issue a diagnostic warning.
The expectation here is that (a) the correct value will be assigned in SSA, or (b) if there's a branch scope where it remains initialized to Poison, the value will subsequently not be used. (The latter case is the one that we needed to implement this change for.)