Change default validation behavior

include/dxc/Support/HLSLOptions.h

@@ -115,7 +115,7 @@ struct RewriterOpts {
 };
 
 enum class ValidatorSelection : int {
- Auto, // Try DXIL.dll; fallback to internal validator
+ Auto, // Force internal validator (even if DXIL.dll is present)
  Internal, // Force internal validator (even if DXIL.dll is present)
  External, // Use DXIL.dll, failing compilation if not available
  Invalid = -1 // Invalid

tools/clang/tools/dxcompiler/dxcutil.cpp

@@ -49,23 +49,33 @@ HRESULT RunInternalValidator(IDxcValidator *pValidator,
 namespace {
 // AssembleToContainer helper functions.
 
+// return true if the internal validator was used, false otherwise
 bool CreateValidator(CComPtr<IDxcValidator> &pValidator,
  hlsl::options::ValidatorSelection SelectValidator =
  hlsl::options::ValidatorSelection::Auto) {
  bool bInternal =
  SelectValidator == hlsl::options::ValidatorSelection::Internal;
  bool bExternal =
  SelectValidator == hlsl::options::ValidatorSelection::External;
- if (!bInternal && DxilLibIsEnabled())
- DxilLibCreateInstance(CLSID_DxcValidator, &pValidator);
+ bool bAuto = SelectValidator == hlsl::options::ValidatorSelection::Auto;
 
- bool bInternalValidator = false;
- if (pValidator == nullptr) {
-  IFTBOOL(!bExternal, DXC_E_VALIDATOR_MISSING);
+ // default behavior uses internal validator, as well as
+ // explicitly specifying internal
+ if (bInternal || bAuto) {
  IFT(CreateDxcValidator(IID_PPV_ARGS(&pValidator)));
- bInternalValidator = true;
+ return true;
+ }
+
+ if (bExternal) {
+ // if external was explicitly specified, but no
+ // external validator could be found (no DXIL.dll), then error
+ IFTBOOL(DxilLibIsEnabled(), DXC_E_VALIDATOR_MISSING);
+ IFT(DxilLibCreateInstance(CLSID_DxcValidator, &pValidator));
+
+ return false;
  }
- return bInternalValidator;
+
+ return false;
 }
 
 } // namespace