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

[via llvm-commits]

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@@ -145,20 +134,30 @@ static bool parse(LLVMContext *Ctx, ModuleRootSignature *MRS, NamedMDNode *Root,
 }
 
 static bool validate(LLVMContext *Ctx, ModuleRootSignature *MRS) {
-  if (dxbc::RootSignatureValidations::validateRootFlag(MRS->Flags)) {
+  if (!dxbc::RootSignatureValidations::isValidRootFlag(MRS->Flags)) {
     return reportError(Ctx, "Invalid Root Signature flag value");
   }
   return false;
 }
 
 std::optional<ModuleRootSignature>
-ModuleRootSignature::analyzeModule(Module &M, const Function *F) {
-  ModuleRootSignature MRS;
+ModuleRootSignature::analyzeModule(Module &M, ModuleMetadataInfo MMI) {
+  if (MMI.ShaderProfile == Triple::Library)
+    return std::nullopt;
+
   LLVMContext *Ctx = &M.getContext();
 
+  if (MMI.EntryPropertyVec.size() != 1) {
+    reportError(Ctx, "More than one entry function defined.");
+    return std::nullopt;
+  }
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joaosaffran wrote:

I've added a few tests to cover this scenario. There are other parts of DXContainerGlobals that enforce to exist a single entry function. Based on the team discussion, this is safe to assume when generating DXContainer. We might need a different workflow when we add support to Library Shaders though 

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