actually use external opts in dxc

Author: bob80905

lib/DxcSupport/dxcapi.extval.cpp

@@ -405,8 +405,7 @@ HRESULT DxcDllExtValidationLoader::CreateInstance2Impl(
 HRESULT
 DxcDllExtValidationLoader::InitializeForDll(LPCSTR dllName, LPCSTR fnName) {
   // Load dxcompiler.dll
-  HRESULT Result =
-      DxCompilerSupport.InitializeForDll(kDxCompilerLib, "DxcCreateInstance");
+  HRESULT Result = DxCompilerSupport.InitializeForDll(dllName, fnName);
   // if dxcompiler.dll fails to load, return the failed HRESULT
   if (FAILED(Result)) {
     FailureReason = FailedCompilerLoad;

tools/clang/tools/dxclib/dxc.cpp

@@ -1456,7 +1456,14 @@ int dxc::main(int argc, const char **argv_) {
     // Setup a helper DLL.
     DxcDllExtValidationLoader dxcSupport;
     {
-      HRESULT dllResult = dxcSupport.initialize();
+      HRESULT dllResult;
+      if (!dxcOpts.ExternalLib.empty() || !dxcOpts.ExternalFn.empty())
+        dllResult =
+            dxcSupport.InitializeForDll(dxcOpts.ExternalLib.str().c_str(),
+                                        dxcOpts.ExternalFn.str().c_str());
+      else
+        dllResult = dxcSupport.initialize();
+
       if (DXC_FAILED(dllResult)) {
         switch (dxcSupport.getFailureReason()) {
         case dxcSupport.FailedCompilerLoad: {