[clang] [HLSL] Implement `SpirvType` and `SpirvOpaqueType` (PR #134034)

[Aaron Ballman via cfe-commits]

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@@ -4855,6 +4857,17 @@ LinkageInfo LinkageComputer::computeTypeLinkageInfo(const Type *T) {
     return computeTypeLinkageInfo(cast<HLSLAttributedResourceType>(T)
                                       ->getContainedType()
                                       ->getCanonicalTypeInternal());
+  case Type::HLSLInlineSpirv:
+    return LinkageInfo::external();
+    {
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AaronBallman wrote:

In the interim, I think we should remove the code after the `return`. If the current behavior is good enough for HLSL needs today, we can remove the dead code and resurrect it later from version control if needed. WDYT?

https://github.com/llvm/llvm-project/pull/134034