[llvm] [DXIL] Add support for root signature flag element in DXContainer (PR #123147)

[Justin Bogner via llvm-commits]

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@@ -0,0 +1,73 @@
+//===- DXILRootSignature.h - DXIL Root Signature helper objects
+//---------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file This file contains helper objects and APIs for working with DXIL
+///       Root Signatures.
+///
+//===----------------------------------------------------------------------===//
+
+#include "llvm/IR/Metadata.h"
+#include "llvm/IR/PassManager.h"
+#include "llvm/Pass.h"
+#include <optional>
+
+namespace llvm {
+namespace dxil {
+
+enum class RootSignatureElementKind {
+  None = 0,
+  RootFlags = 1,
+  RootConstants = 2,
+  RootDescriptor = 3,
+  DescriptorTable = 4,
+  StaticSampler = 5
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bogner wrote:

I also think it would probably be better to only define these as we implement them - this will mean that when adding a new one all of the switch statements that need to be updated will trigger a -Wcovered-switch warning, making it easier to ensure adding an element kind updates all of the important places.

https://github.com/llvm/llvm-project/pull/123147