[spirv] Fix the UserSemantic decoration string. (#2581)

tools/clang/lib/SPIRV/DeclResultIdMapper.cpp

@@ -1923,7 +1923,7 @@ bool DeclResultIdMapper::createStageVars(
 
     // Emit OpDecorate* instructions to link this stage variable with the HLSL
     // semantic it is created for
-    spvBuilder.decorateHlslSemantic(varInstr, stageVar.getSemanticInfo().str);
+    spvBuilder.decorateHlslSemantic(varInstr, stageVar.getSemanticStr());
 
     // We have semantics attached to this decl, which means it must be a
     // function/parameter/variable. All are DeclaratorDecls.

tools/clang/test/CodeGenSPIRV/spirv.user-semantic.vs.hlsl

@@ -0,0 +1,31 @@
+// Run: %dxc -T vs_6_0 -E main -fspv-reflect
+
+
+// CHECK: OpExtension "SPV_GOOGLE_hlsl_functionality1"
+
+// CHECK: OpName %in_var_POSITION "in.var.POSITION"
+// CHECK: OpName %in_var_TEXCOORD4 "in.var.TEXCOORD4"
+// CHECK: OpName %in_var_TEXCOORD5 "in.var.TEXCOORD5"
+
+// CHECK: OpDecorateString %in_var_POSITION UserSemantic "POSITION"
+// CHECK: OpDecorateString %in_var_TEXCOORD4 UserSemantic "TEXCOORD4"
+// CHECK: OpDecorateString %in_var_TEXCOORD5 UserSemantic "TEXCOORD5"
+
+// CHECK: %in_var_POSITION = OpVariable %_ptr_Input_v3float Input
+// CHECK: %in_var_TEXCOORD4 = OpVariable %_ptr_Input_mat4v3float Input
+// CHECK: %in_var_TEXCOORD5 = OpVariable %_ptr_Input_v4float Input
+
+struct SInstanceData {
+	float4x3 VisualToWorld;
+	float4 Output;
+};
+
+struct VS_INPUT {
+	float3 Position : POSITION;
+	SInstanceData InstanceData : TEXCOORD4;
+};
+
+float4 main(const VS_INPUT v) : SV_Position {
+	const SInstanceData	I = v.InstanceData;
+  return I.Output;
+}

tools/clang/unittests/SPIRV/CodeGenSpirvTest.cpp

@@ -1427,6 +1427,11 @@ TEST_F(FileTest, SpirvStageIOAliasBuiltIn) {
   runFileTest("spirv.interface.alias-builtin.hlsl");
 }
 
+// For testing UserSemantic decoration
+TEST_F(FileTest, SpirvUserSemanticVS) {
+  runFileTest("spirv.user-semantic.vs.hlsl");
+}
+
 TEST_F(FileTest, SpirvStageIO16bitTypes) {
   runFileTest("spirv.stage-io.16bit.hlsl");
 }