HLSL: ignore geometry attributes on non-GS stages.

If a shader includes a mixture of several stages, such as HS and GS,
the non-stage output geometry should be ignored, lest it conflict
with the stage output.

Test/hlsl.gs-hs-mix.tesc

@@ -0,0 +1,119 @@
+cbuffer UniformBlock0 : register(b0)
+{
+  float4x4 model_view_matrix;
+  float4x4 proj_matrix;
+  float4x4 model_view_proj_matrix;
+  float3x3 normal_matrix;
+  float3   color;
+  float3   view_dir;
+  float3   tess_factor;
+};
+
+// =============================================================================
+// Hull Shader
+// =============================================================================
+struct HSInput {
+  float3 PositionWS : POSITION;
+  float3 NormalWS   : NORMAL;
+};
+
+struct HSOutput {
+  float3 PositionWS : POSITION;
+};
+
+struct HSTrianglePatchConstant {
+  float  EdgeTessFactor[3] : SV_TessFactor;
+  float  InsideTessFactor  : SV_InsideTessFactor;
+  float3 NormalWS[3]       : NORMAL;
+};
+
+HSTrianglePatchConstant HSPatchConstant(InputPatch<HSInput, 3> patch)
+{
+  float3 roundedEdgeTessFactor = tess_factor;
+  float  roundedInsideTessFactor = 3;
+  float  insideTessFactor = 1;
+
+  HSTrianglePatchConstant result;
+
+  // Edge and inside tessellation factors
+  result.EdgeTessFactor[0] = roundedEdgeTessFactor.x;
+  result.EdgeTessFactor[1] = roundedEdgeTessFactor.y;
+  result.EdgeTessFactor[2] = roundedEdgeTessFactor.z;
+  result.InsideTessFactor  = roundedInsideTessFactor;
+
+  // Constant data
+  result.NormalWS[0] = patch[0].NormalWS;
+  result.NormalWS[1] = patch[1].NormalWS;
+  result.NormalWS[2] = patch[2].NormalWS;
+
+  return result;
+}
+
+[domain("tri")]
+[partitioning("fractional_odd")]
+[outputtopology("triangle_ccw")]
+[outputcontrolpoints(3)]
+[patchconstantfunc("HSPatchConstant")]
+HSOutput HSMain(
+  InputPatch<HSInput, 3>  patch,
+  uint                    id : SV_OutputControlPointID
+)
+{
+  HSOutput output;
+  output.PositionWS = patch[id].PositionWS;
+  return output;
+}
+
+// =============================================================================
+// Geometry Shader
+// =============================================================================
+struct GSVertexInput {
+  float3 PositionWS : POSITION;
+  float3 NormalWS   : NORMAL;
+};
+
+struct GSVertexOutput {
+  float4 PositionCS : SV_POSITION;
+};
+
+[maxvertexcount(6)]
+void GSMain(
+  triangle GSVertexInput            input[3],
+  inout LineStream<GSVertexOutput>  output
+)
+{
+
+  float3 P0 = input[0].PositionWS.xyz;
+  float3 P1 = input[1].PositionWS.xyz;
+  float3 P2 = input[2].PositionWS.xyz;
+
+  GSVertexOutput vertex;
+  // Totally hacky...
+  P0.z += 0.001;
+  P1.z += 0.001;
+  P2.z += 0.001;
+  float4 Q0 = mul(proj_matrix, float4(P0, 1.0));
+  float4 Q1 = mul(proj_matrix, float4(P1, 1.0));
+  float4 Q2 = mul(proj_matrix, float4(P2, 1.0));
+
+  // Edge 0
+  vertex.PositionCS = Q0;
+  output.Append(vertex);
+  vertex.PositionCS = Q1;
+  output.Append(vertex);
+  output.RestartStrip();
+
+  // Edge 1
+  vertex.PositionCS = Q1;
+  output.Append(vertex);
+  vertex.PositionCS = Q2;
+  output.Append(vertex);
+  output.RestartStrip();
+
+  // Edge 2
+  vertex.PositionCS = Q2;
+  output.Append(vertex);
+  vertex.PositionCS = Q0;
+  output.Append(vertex);
+  output.RestartStrip();
+}