[llvm] [DirectX] Adding support for Root Descriptors in obj2yaml/yaml2obj (PR #137259)

[Finn Plummer via llvm-commits]

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@@ -121,16 +121,19 @@ namespace DirectX {
 struct RootParameterView {
   const dxbc::RootParameterHeader &Header;
   StringRef ParamData;
-  RootParameterView(const dxbc::RootParameterHeader &H, StringRef P)
+  RootParameterView(uint32_t V, const dxbc::RootParameterHeader &H, StringRef P)
       : Header(H), ParamData(P) {}
 
-  template <typename T> Expected<T> readParameter() {
-    T Struct;
-    if (sizeof(T) != ParamData.size())
+  template <typename T, typename VersionT = T> Expected<T> readParameter() {
+    assert(sizeof(VersionT) <= sizeof(T) &&
+           "Parameter of higher version must inherit all previous version data "
+           "members");
+    if (sizeof(VersionT) != ParamData.size())
       return make_error<GenericBinaryError>(
           "Reading structure out of file bounds", object_error::parse_failed);
 
-    memcpy(&Struct, ParamData.data(), sizeof(T));
+    T Struct;
+    memcpy(&Struct, ParamData.data(), sizeof(VersionT));
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inbelic wrote:

I do think with the NFC changes in the refactor pr and now the way the structs will be used it makes less sense to do the way I suggested (using variants of the versioned structs)

https://github.com/llvm/llvm-project/pull/137259