[llvm] [DirectX] adding support to read/write descriptor table data using obj2yaml/yaml2obj (PR #138315)

[Justin Bogner via llvm-commits]

================
@@ -106,13 +125,82 @@ struct RootParameterYamlDesc {
     case llvm::to_underlying(dxbc::RootParameterType::UAV):
       Descriptor = RootDescriptorYaml();
       break;
+    case llvm::to_underlying(dxbc::RootParameterType::DescriptorTable):
+      Table = DescriptorTableYaml();
+      break;
+    }
+  }
+
+  ~RootParameterYamlDesc() {
+    switch (Type) {
+
+    case llvm::to_underlying(dxbc::RootParameterType::Constants32Bit):
+      Constants.~RootConstantsYaml();
+      break;
+    case llvm::to_underlying(dxbc::RootParameterType::CBV):
+    case llvm::to_underlying(dxbc::RootParameterType::SRV):
+    case llvm::to_underlying(dxbc::RootParameterType::UAV):
+      Descriptor.~RootDescriptorYaml();
+      break;
+    case llvm::to_underlying(dxbc::RootParameterType::DescriptorTable):
+      Table.~DescriptorTableYaml();
+      break;
     }
   }
 
+  RootParameterYamlDesc(const RootParameterYamlDesc &Other)
+      : Type(Other.Type), Visibility(Other.Visibility), Offset(Other.Offset) {
+    // Initialize the appropriate union member based on Type
+    switch (Type) {
+    case llvm::to_underlying(dxbc::RootParameterType::Constants32Bit):
+      // Placement new to construct the union member
+      new (&Constants) RootConstantsYaml(Other.Constants);
+      break;
+    case llvm::to_underlying(dxbc::RootParameterType::CBV):
+    case llvm::to_underlying(dxbc::RootParameterType::SRV):
+    case llvm::to_underlying(dxbc::RootParameterType::UAV):
+      new (&Descriptor) RootDescriptorYaml(Other.Descriptor);
+      break;
+    case llvm::to_underlying(dxbc::RootParameterType::DescriptorTable):
+      new (&Table) DescriptorTableYaml(Other.Table);
+      break;
+    }
+  }
+
+  RootParameterYamlDesc &operator=(const RootParameterYamlDesc &Other) {
+    if (this != &Other) {
+      // First, destroy the current union member
+      this->~RootParameterYamlDesc();
+
+      // Copy the basic members
+      Type = Other.Type;
+      Visibility = Other.Visibility;
+      Offset = Other.Offset;
+
+      // Initialize the new union member based on the Type from 'other'
+      switch (Type) {
+      case llvm::to_underlying(dxbc::RootParameterType::Constants32Bit):
+        new (&Constants) RootConstantsYaml(Other.Constants);
+        break;
+      case llvm::to_underlying(dxbc::RootParameterType::CBV):
+      case llvm::to_underlying(dxbc::RootParameterType::SRV):
+      case llvm::to_underlying(dxbc::RootParameterType::UAV):
+        new (&Descriptor) RootDescriptorYaml(Other.Descriptor);
+        break;
+      case llvm::to_underlying(dxbc::RootParameterType::DescriptorTable):
+        new (&Table) DescriptorTableYaml(Other.Table);
+        break;
+      }
+    }
+    return *this;
+  }
+
+  // ToDo: Fix this (Already have a follow up PR with it)
----------------
bogner wrote:

I haven't seen the other PR yet, so it isn't clear to me how much work it would be, but shouldn't we just do this first? Presumably all of the custom constructor/destructor logic gets cleaned up by the re-design, right?

It's hard to tell what to review with this kind of TODO...

https://github.com/llvm/llvm-project/pull/138315