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

[Shafik Yaghmour via cfe-commits]

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@@ -6361,6 +6362,143 @@ class HLSLAttributedResourceType : public Type, public llvm::FoldingSetNode {
   findHandleTypeOnResource(const Type *RT);
 };
 
+/// Instances of this class represent operands to a SPIR-V type instruction.
+class SpirvOperand {
+public:
+  enum SpirvOperandKind : unsigned char {
+    Invalid,    ///< Uninitialized.
+    ConstantId, ///< Integral value to represent as a SPIR-V OpConstant
+                ///< instruction ID.
+    Literal,    ///< Integral value to represent as an immediate literal.
+    TypeId,     ///< Type to represent as a SPIR-V type ID.
+
+    Max,
+  };
+
+private:
+  SpirvOperandKind Kind = Invalid;
+
+  QualType ResultType;
+  llvm::APInt Value; // Signedness of constants is represented by ResultType.
+
+public:
+  SpirvOperand() : Kind(Invalid), ResultType(), Value() {}
+
+  SpirvOperand(SpirvOperandKind Kind, QualType ResultType, llvm::APInt Value)
+      : Kind(Kind), ResultType(ResultType), Value(Value) {}
+
+  SpirvOperand(const SpirvOperand &Other) { *this = Other; }
+  ~SpirvOperand() {}
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shafik wrote:

It would have been better to just default this.

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