GLSL: Fix #1330: default outputs for GL_NV_geometry_shader_passthrough

Test/baseResults/spv.GeometryShaderPassthrough.geom.out

@@ -11,7 +11,7 @@ spv.GeometryShaderPassthrough.geom
                               EntryPoint Geometry 4  "main" 10 14
                               ExecutionMode 4 Triangles
                               ExecutionMode 4 Invocations 1
-                              ExecutionMode 4 OutputVertices
+                              ExecutionMode 4 OutputVertices 3
                               Source GLSL 450
                               SourceExtension  "GL_NV_geometry_shader_passthrough"
                               Name 4  "main"

glslang/MachineIndependent/ParseHelper.cpp

@@ -3977,6 +3977,26 @@ void TParseContext::finish()
     default:
         break;
     }
+
+    // Set default outputs for GL_NV_geometry_shader_passthrough
+    if (language == EShLangGeometry && extensionTurnedOn(E_SPV_NV_geometry_shader_passthrough)) {
+        if (intermediate.getOutputPrimitive() == ElgNone) {
+            switch (intermediate.getInputPrimitive()) {
+            case ElgPoints:      intermediate.setOutputPrimitive(ElgPoints);    break;
+            case ElgLines:       intermediate.setOutputPrimitive(ElgLineStrip); break;
+            case ElgTriangles:   intermediate.setOutputPrimitive(ElgTriangles); break;
+            default: break;
+            }
+        }
+        if (intermediate.getVertices() == TQualifier::layoutNotSet) {
+            switch (intermediate.getInputPrimitive()) {
+            case ElgPoints:      intermediate.setVertices(1); break;
+            case ElgLines:       intermediate.setVertices(2); break;
+            case ElgTriangles:   intermediate.setVertices(3); break;
+            default: break;
+            }
+        }
+    }
 }
 
 //