adding llvm unreachable and testing test

Author: joaosaffran

llvm/lib/Target/DirectX/DXILRootSignature.cpp

@@ -69,7 +69,7 @@ static bool parseRootSignatureElement(LLVMContext *Ctx,
                        "Invalid Root Element: " + ElementText->getString());
   }
 
-  return true;
+  llvm_unreachable("Root signature element kind not expected.");
 }
 
 static bool parse(LLVMContext *Ctx, ModuleRootSignature *MRS, NamedMDNode *Root,

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

@@ -0,0 +1,26 @@
+; RUN: not llc %s --filetype=obj -o -
+; expected-error@-1: More than one entry function defined
+
+target triple = "dxil-unknown-shadermodel6.0-compute"
+
+
+define void @main() #0 {
+entry:
+  ret void
+}
+
+define void @anotherMain() #1 {
+entry:
+  ret void
+}
+
+attributes #0 = { "hlsl.numthreads"="1,1,1" "hlsl.shader"="compute" }
+attributes #1 = { "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 = !{ ptr @anotherMain, !6 } ; function, root signature
+!6 = !{ !7 } ; list of root signature elements
+!7 = !{ !"RootFlags", i32 2 } ; 1 = allow_input_assembler_input_layout