implement stage 2

Author: bob80905

include/dxc/Support/dxcapi.extval.h

@@ -0,0 +1,20 @@
+#include "dxc/Support/dxcapi.use.h"
+#include "dxc/dxcapi.h"
+
+class DxcDllExtValidationSupport : public dxc::DxcDllSupport {
+  // DxcDllExtValidationSupport manages the
+  // lifetime of dxcompiler.dll, while the member, m_DxilSupport,
+  // manages the lifetime of dxil.dll
+  dxc::DxcDllSupport m_DxilSupport;
+
+  std::string DxilDllPath;
+  // override DxcDllSupport's implementation of InitializeInternal,
+  // adding the environment variable value check for a path to a dxil.dll
+
+  std::string GetDxilDLLPathExt() { return DxilDllPath; }
+  bool DxilDllSuccessfullyLoaded() {
+    return !DxilDllPath.empty() && !m_DxilSupport.IsEnabled();
+  }
+
+  HRESULT InitializeInternal(LPCSTR dllName, LPCSTR fnName);
+};

include/dxc/Support/dxcapi.use.h

@@ -13,6 +13,10 @@
 #define __DXCAPI_USE_H__
 
 #include "dxc/dxcapi.h"
+#include <cstdlib>     // for getenv
+#include <string>
+#include <filesystem>  // C++17 and later
+#include <dxc/Support/Global.h> // for hresult handling with DXC_FAILED
 
 namespace dxc {
 
@@ -85,13 +89,13 @@ class DxcDllSupport {
     other.m_createFn2 = nullptr;
   }
 
-  ~DxcDllSupport() { Cleanup(); }
+  virtual ~DxcDllSupport() { Cleanup(); }
 
-  HRESULT Initialize() {
+  HRESULT virtual Initialize() {
     return InitializeInternal(kDxCompilerLib, "DxcCreateInstance");
   }
 
-  HRESULT InitializeForDll(LPCSTR dll, LPCSTR entryPoint) {
+  HRESULT virtual InitializeForDll(LPCSTR dll, LPCSTR entryPoint) {
     return InitializeInternal(dll, entryPoint);
   }
 
@@ -100,7 +104,8 @@ class DxcDllSupport {
     return CreateInstance(clsid, __uuidof(TInterface), (IUnknown **)pResult);
   }
 
-  HRESULT CreateInstance(REFCLSID clsid, REFIID riid, IUnknown **pResult) {
+  HRESULT virtual CreateInstance(REFCLSID clsid, REFIID riid,
+                                 IUnknown **pResult) {
     if (pResult == nullptr)
       return E_POINTER;
     if (m_dll == nullptr)
@@ -116,7 +121,7 @@ class DxcDllSupport {
                            (IUnknown **)pResult);
   }
 
-  HRESULT CreateInstance2(IMalloc *pMalloc, REFCLSID clsid, REFIID riid,
+  HRESULT virtual CreateInstance2(IMalloc *pMalloc, REFCLSID clsid, REFIID riid,
                           IUnknown **pResult) {
     if (pResult == nullptr)
       return E_POINTER;
@@ -128,11 +133,11 @@ class DxcDllSupport {
     return hr;
   }
 
-  bool HasCreateWithMalloc() const { return m_createFn2 != nullptr; }
+  bool virtual HasCreateWithMalloc() const { return m_createFn2 != nullptr; }
 
   bool IsEnabled() const { return m_dll != nullptr; }
 
-  void Cleanup() {
+  void virtual Cleanup() {
     if (m_dll != nullptr) {
       m_createFn = nullptr;
       m_createFn2 = nullptr;
@@ -145,7 +150,7 @@ class DxcDllSupport {
     }
   }
 
-  HMODULE Detach() {
+  HMODULE virtual Detach() {
     HMODULE hModule = m_dll;
     m_dll = nullptr;
     return hModule;

lib/DxcSupport/CMakeLists.txt

@@ -10,6 +10,7 @@ add_llvm_library(LLVMDxcSupport
   WinAdapter.cpp
   WinIncludes.cpp
   WinFunctions.cpp
+  dxcapi.extval.cpp
   )
 
 #generate header with platform-specific library name

lib/DxcSupport/dxcapi.extval.cpp

@@ -0,0 +1,43 @@
+#include "dxc/Support/WinIncludes.h"
+
+#include "dxc/Support/dxcapi.use.h"
+
+#include "dxc/Support/FileIOHelper.h"
+#include "dxc/Support/Global.h"
+#include "dxc/Support/SharedLibAffix.h" // header generated during DXC build
+#include "dxc/Support/Unicode.h"
+#include "dxc/Support/WinFunctions.h"
+
+#include "dxc/Support/dxcapi.extval.h"
+
+HRESULT DxcDllExtValidationSupport::InitializeInternal(LPCSTR dllName,
+                                                       LPCSTR fnName) {
+  // Load dxcompiler.dll
+  HRESULT result = InitializeForDll(dllName, fnName);
+  // if dxcompiler.dll fails to load, return the failed HRESULT
+  if (DXC_FAILED(result)) {
+    return result;
+  }
+
+  // now handle external dxil.dll
+  const char *envVal = std::getenv("DXC_DXIL_DLL_PATH");
+  if (!envVal || std::string(envVal).empty()) {
+    return S_OK;
+  }
+
+  std::string DllPathStr(envVal);
+  DxilDllPath = DllPathStr;
+  std::filesystem::path DllPath(DllPathStr);
+
+  // Check if path is absolute and exists
+  if (!DllPath.is_absolute() || !std::filesystem::exists(DllPath)) {
+    return S_OK;
+  }
+  // code that calls this function is responsible for checking
+  // to see if dxil.dll is successfully loaded.
+  // the CheckDxilDLLLoaded function can determine whether there were any
+  // problems loading dxil.dll or not
+  m_DxilSupport.InitializeForDll(DllPathStr.data(), fnName);
+
+  return S_OK;
+}