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

[Justin Bogner via llvm-commits]

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@@ -95,8 +92,14 @@ static bool parse(LLVMContext *Ctx, ModuleRootSignature *MRS, NamedMDNode *Root,
       continue;
     }
 
+    const MDOperand &FunctionPointerMdNode = Node->getOperand(0);
+    if (FunctionPointerMdNode == nullptr) {
+      // Function was pruned during compilation.
+      continue;
+    }
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bogner wrote:

I don't think we should be able to get here without hand-written invalid IR. The `RootSignature-MultipleEntryFunctions.ll` doesn't have multiple entry functions - it has entry function metadata for functions that are not entry functions - since `@main` doesn't have `hlsl.shader` metadata and is not exported it's removed by DXILFinalizeLinkage.

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