[clang] [llvm] [HLSL][RootSignature] Add `hlsl-rootsig-ver` option to specify root signature version (PR #144813)

[Justin Bogner via llvm-commits]

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@@ -99,6 +99,12 @@ enum class SamplerFeedbackType : uint32_t {
 const unsigned MinWaveSize = 4;
 const unsigned MaxWaveSize = 128;
 
+// D3D_ROOT_SIGNATURE_VERSION
+enum class RootSignatureVersion {
+  rootsig_1_0 = 0x1,
+  rootsig_1_1 = 0x2,
+};
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bogner wrote:

Should these be defined in BinaryFormat/DXContainer.h with the other d3d12 constants? They don't seem like they belong in DXILABI to me.

Also the naming here feels a bit awkward - we're kind of repeating ourselves with `RootSignatureVersion::rootsig_1_0` - Should it just be `RootSignatureVersion::V1_0` or something like that?

https://github.com/llvm/llvm-project/pull/144813