[dxbc] Implemented Nop instruction

Required for Metal Gear Solid V.

src/dxbc/dxbc_compiler.cpp

@@ -96,6 +96,9 @@ namespace dxvk {
       case DxbcInstClass::Interpolate:
         return this->emitInterpolate(ins);
       
+      case DxbcInstClass::NoOperation:
+        return;
+      
       case DxbcInstClass::TextureQuery:
         return this->emitTextureQuery(ins);
         

src/dxbc/dxbc_defs.cpp

@@ -282,7 +282,7 @@ namespace dxvk {
       { DxbcOperandKind::SrcReg, DxbcScalarType::Float32 },
     } },
     /* Nop                                  */
-    { },
+    { 0, DxbcInstClass::NoOperation },
     /* Not                                  */
     { 2, DxbcInstClass::VectorAlu, {
       { DxbcOperandKind::DstReg, DxbcScalarType::Uint32 },

src/dxbc/dxbc_defs.h

@@ -44,6 +44,7 @@ namespace dxvk {
     HullShaderPhase,    ///< Hull shader phase declaration
     HullShaderInstCnt,  ///< Hull shader phase instance count
     Interpolate,        ///< Input attribute interpolation
+    NoOperation,        ///< The most useful instruction class
     TextureQuery,       ///< Texture query instruction
     TextureQueryLod,    ///< Texture LOD query instruction
     TextureQueryMs,     ///< Multisample texture query

src/dxbc/dxbc_options.cpp

@@ -11,7 +11,7 @@ namespace dxvk {
     
     if (vendor == DxvkGpuVendor::Nvidia
      && (devProps.driverVersion < VK_MAKE_VERSION(396, 18, 0)
-      || getEnvVar(L"__GL_NextGenCompiler") == "0")) {
+      || env::getEnvVar(L"__GL_NextGenCompiler") == "0")) {
       // Older versions of the driver expect the
       // coordinate vector to have an extra component
       this->addExtraDrefCoordComponent = true;