[clang] [HLSL] Strict Availability Diagnostics (PR #93860)

[Damyan Pepper via cfe-commits]

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@@ -157,6 +157,18 @@ static bool ShouldDiagnoseAvailabilityInContext(
     }
   }
 
+  // In HLSL, emit diagnostic during parsing only if the diagnostic
+  // mode is set to strict (-fhlsl-strict-availability), and either the decl
+  // availability is not restricted to a specific environment/shader stage,
+  // or the target stage is known (= it is not shader library).
+  if (S.getLangOpts().HLSL) {
+    if (!S.getLangOpts().HLSLStrictAvailability ||
+        (DeclEnv != nullptr &&
+         S.getASTContext().getTargetInfo().getTriple().getEnvironment() ==
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damyanp wrote:

Here (and a bit further down in the PR as well) there are places that assume that "not library" implies "known target stage". I wonder if we're opening ourselves up to subtle bugs issues in the future if we end up adding another library-like target?

Maybe this is unlikely enough that we can deal with that later?

https://github.com/llvm/llvm-project/pull/93860