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

This implements the design proposed by [Representing SpirvType in
Clang's Type System](https://github.com/llvm/wg-hlsl/pull/181). It
creates `HLSLInlineSpirvType` as a new `Type` subclass, and
`__hlsl_spirv_type` as a new builtin type template to create such a
type.

This new type is lowered to the `spirv.Type` target extension type, as
described in [Target Extension Types for Inline SPIR-V and Decorated
Types](https://github.com/llvm/wg-hlsl/blob/main/proposals/0017-inline-spirv-and-decorated-types.md).

1 files changed, 4 insertions, 0 deletions

diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 1b3d3c2..cc9916a 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -604,6 +604,10 @@ void TypeLocWriter::VisitHLSLAttributedResourceTypeLoc(
   // Nothing to do.
 }
 
+void TypeLocWriter::VisitHLSLInlineSpirvTypeLoc(HLSLInlineSpirvTypeLoc TL) {
+  // Nothing to do.
+}
+
 void TypeLocWriter::VisitTemplateTypeParmTypeLoc(TemplateTypeParmTypeLoc TL) {
   addSourceLocation(TL.getNameLoc());
 }