Require outputtopology attribute on Hull shader

There was an existing check in DXIL validation that failed when the
outputtopology was not set for a Hull shader. Rather than duplicate this
check in the SPIR-V backend/validator, it seems correct to check that it
is present in Sema.

This PR needs review from someone who is more familiar with the HLSL spec
for hull shaders to verify that this check is correct though.

Fixes microsoft#3740

tools/clang/lib/Sema/SemaHLSL.cpp

@@ -15143,6 +15143,9 @@ void DiagnoseHullEntry(Sema &S, FunctionDecl *FD, llvm::StringRef StageName) {
   if (!Attr)
     S.Diags.Report(FD->getLocation(), diag::err_hlsl_missing_attr)
         << StageName << "patchconstantfunc";
+  if (!(FD->getAttr<HLSLOutputTopologyAttr>()))
+    S.Diags.Report(FD->getLocation(), diag::err_hlsl_missing_attr)
+        << StageName << "outputtopology";
 
   return;
 }

tools/clang/test/CodeGenSPIRV/operator.overloading.resource.type.check.hlsl

@@ -11,6 +11,7 @@ struct OUTPUT
 };
 
 [outputcontrolpoints(3)]
+[outputtopology("point")]
 [patchconstantfunc("foo")]
 
 INPUT main(InputPatch<INPUT, 3> Input,

tools/clang/test/HLSLFileCheck/hlsl/functions/attribute/outputtopology_missing.hlsl

@@ -0,0 +1,17 @@
+// RUN: %dxc -T hs_6_0 -E Hull %s | FileCheck %s
+
+struct ControlPoint { float4 position : POSITION; }; 
+struct HullPatchOut {
+    float edge [3] : SV_TessFactor;
+    float inside : SV_InsideTessFactor;
+};
+
+HullPatchOut HullConst (InputPatch<ControlPoint,3> v) { return (HullPatchOut)0; }
+
+//CHECK: error: hull entry point must have a valid outputtopology attribute
+
+[domain("tri")]
+[partitioning("fractional_odd")]
+[patchconstantfunc("HullConst")]
+[outputcontrolpoints(3)]
+ControlPoint Hull (InputPatch<ControlPoint,3> v, uint id : SV_OutputControlPointID) { return v[id]; }

tools/clang/test/HLSLFileCheck/hlsl/functions/attribute/patch_constant_function_missing.hlsl

@@ -14,6 +14,7 @@ float4 fooey()
 [shader("hull")]
 // CHECK: error: patch constant function 'NotFooey' must be defined
 [patchconstantfunc("NotFooey")]
+[outputtopology("point")]
 float4 main(float a : A, float b:B) : SV_TARGET
 {
   float4 f = b;

tools/clang/test/HLSLFileCheck/hlsl/functions/recursion/library_hull_recursion.hlsl

@@ -41,6 +41,7 @@ HSPerPatchData HSPerPatchFunc1()
 
 [shader("hull")]
 [patchconstantfunc("HSPerPatchFunc1")]
+[outputtopology("point")]
 float4 main(float a : A, float b:B) : SV_TARGET
 {
   float4 f = b;