adding test for null function

Author: joaosaffran

llvm/lib/Target/DirectX/DXContainerGlobals.cpp

@@ -169,7 +169,7 @@ void DXContainerGlobals::addRootSignature(Module &M,
   if (FuncRs == RSA.end())
     return;
 
-  const RootSignatureDesc &RS = FuncRs->getSecond();
+  const RootSignatureDesc &RS = FuncRs->second;
   SmallString<256> Data;
   raw_svector_ostream OS(Data);
 

llvm/lib/Target/DirectX/DXILRootSignature.cpp

@@ -132,6 +132,8 @@ analyzeModule(Module &M) {
     // Function was pruned during compilation.
     const MDOperand &FunctionPointerMdNode = RSDefNode->getOperand(0);
     if (FunctionPointerMdNode == nullptr) {
+      reportError(
+          Ctx, "Function associated with Root Signature definition is null.");
       continue;
     }
 

llvm/test/CodeGen/DirectX/ContainerData/RootSignature-NullFunction-Error.ll

@@ -0,0 +1,21 @@
+; RUN: not opt -passes='print<dxil-root-signature>' %s -S -o - 2>&1 | FileCheck %s
+
+; CHECK: error: Function associated with Root Signature definition is null
+; CHECK-NOT: Root Signature Definitions
+
+target triple = "dxil-unknown-shadermodel6.0-compute"
+
+define void @main() #0 {
+entry:
+  ret void
+}
+
+attributes #0 = { "hlsl.numthreads"="1,1,1" "hlsl.shader"="compute" }
+
+!dx.rootsignatures = !{!2, !5} ; list of function/root signature pairs
+!2 = !{ ptr @main, !3 } ; function, root signature
+!3 = !{ !4 } ; list of root signature elements
+!4 = !{ !"RootFlags", i32 1 } ; 1 = allow_input_assembler_input_layout
+!5 = !{ null, !6 } ; function, root signature
+!6 = !{ !7 } ; list of root signature elements
+!7 = !{ !"RootFlags", i32 2 } ; 1 = allow_input_assembler_input_layout