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

[via llvm-commits]

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@@ -0,0 +1,77 @@
+//===- 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/ADT/DenseMap.h"
+#include "llvm/Analysis/DXILMetadataAnalysis.h"
+#include "llvm/IR/DiagnosticInfo.h"
+#include "llvm/IR/Metadata.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/PassManager.h"
+#include "llvm/MC/DXContainerRootSignature.h"
+#include "llvm/Pass.h"
+#include <optional>
+
+namespace llvm {
+namespace dxil {
+
+enum class RootSignatureElementKind { Error = 0, RootFlags = 1 };
+class RootSignatureAnalysis : public AnalysisInfoMixin<RootSignatureAnalysis> {
+  friend AnalysisInfoMixin<RootSignatureAnalysis>;
+  static AnalysisKey Key;
+
+public:
+  RootSignatureAnalysis() = default;
+
+  using Result = SmallDenseMap<const Function *, mcdxbc::RootSignatureDesc>;
+
+  SmallDenseMap<const Function *, mcdxbc::RootSignatureDesc>
+  run(Module &M, ModuleAnalysisManager &AM);
+};
+
+/// Wrapper pass for the legacy pass manager.
+///
+/// This is required because the passes that will depend on this are codegen
+/// passes which run through the legacy pass manager.
+class RootSignatureAnalysisWrapper : public ModulePass {
+private:
+  SmallDenseMap<const Function *, mcdxbc::RootSignatureDesc> FuncToRsMap;
+
+public:
+  static char ID;
+
+  RootSignatureAnalysisWrapper() : ModulePass(ID) {}
+
+  std::optional<mcdxbc::RootSignatureDesc> getForFunction(const Function *F) {
+    auto Lookup = FuncToRsMap.find(F);
+    if (Lookup == FuncToRsMap.end())
+      return std::nullopt;
+    return Lookup->second;
+  }
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joaosaffran wrote:

Sorry, misunderstood the previous comment. I will implement this change.

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