[llvm] [SPIR-V] Fix environment resolution causing legalization crash (PR #179052)

[Viktoria Maximova via llvm-commits]

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@@ -76,6 +74,11 @@ class SPIRVSubtarget : public SPIRVGenSubtargetInfo {
 
   void initAvailableExtensions(
       const std::set<SPIRV::Extension::Extension> &AllowedExtIds);
+  void initAvailableExtInstSets();
+
+  // If Env is Unknown, scan module for "hlsl.shader" attributes to resolve it.
+  // Must be called before any pass that depends on isShader()/isKernel().
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vmaksimo wrote:

Nit: maybe we don't need implementation details in function description - just focus on the function goal (choose kernel or shader environment).

https://github.com/llvm/llvm-project/pull/179052