D3D12: Search the default path of Windows SDK for DXC DLLs

This patch adds another way to get DXC DLLs (dxcompiler.dll and
dxil.dll) by searching the default installation path of Windows x64
SDK (C:\Program Files (x86)\Windows Kits\10\\bin\10.0.[version].0\x64)
so that now Dawn can find these two DLLs when Windows SDK is correctly
installed at the default location.

This patch also forces enabling the "use_dxc" toggle when Dawn can
find DXC DLLs and the device is created with "ShaderFloat16" extension
enabled because currently the HLSL shaders with float16_t can only be
compiled with DXC DLLs.

BUG=dawn:402

Change-Id: I410195d9e079f54faebbca71fff77a71f489f08e
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/33180
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Austin Eng <enga@chromium.org>

src/dawn_native/Device.cpp

@@ -1115,7 +1115,7 @@ namespace dawn_native {
     void DeviceBase::ForceSetToggle(Toggle toggle, bool isEnabled) {
         if (!mOverridenToggles.Has(toggle) && mEnabledToggles.Has(toggle) != isEnabled) {
             dawn::WarningLog() << "Forcing toggle \"" << ToggleEnumToName(toggle) << "\" to "
-                               << isEnabled << "when it was overriden to be " << !isEnabled;
+                               << isEnabled << " when it was overriden to be " << !isEnabled;
         }
         mEnabledToggles.Set(toggle, isEnabled);
     }

src/dawn_native/d3d12/DeviceD3D12.cpp

@@ -195,6 +195,9 @@ namespace dawn_native { namespace d3d12 {
     void Device::ApplyUseDxcToggle() {
         if (!ToBackend(GetAdapter())->GetBackend()->GetFunctions()->IsDXCAvailable()) {
             ForceSetToggle(Toggle::UseDXC, false);
+        } else if (IsExtensionEnabled(Extension::ShaderFloat16)) {
+            // Currently we can only use DXC to compile HLSL shaders using float16.
+            ForceSetToggle(Toggle::UseDXC, true);
         }
     }
 

src/dawn_native/d3d12/PlatformFunctions.cpp

@@ -16,7 +16,89 @@
 
 #include "common/DynamicLib.h"
 
+#include <comdef.h>
+#include <array>
+#include <sstream>
+
 namespace dawn_native { namespace d3d12 {
+    namespace {
+        // Extract Version from "10.0.{Version}.0" if possible, otherwise return 0.
+        uint32_t GetWindowsSDKVersionFromDirectoryName(const char* directoryName) {
+            constexpr char kPrefix[] = "10.0.";
+            constexpr char kPostfix[] = ".0";
+
+            constexpr uint32_t kPrefixLen = sizeof(kPrefix) - 1;
+            constexpr uint32_t kPostfixLen = sizeof(kPostfix) - 1;
+            const uint32_t directoryNameLen = strlen(directoryName);
+
+            if (directoryNameLen < kPrefixLen + kPostfixLen + 1) {
+                return 0;
+            }
+
+            // Check if directoryName starts with "10.0.".
+            if (strncmp(directoryName, kPrefix, kPrefixLen) != 0) {
+                return 0;
+            }
+
+            // Check if directoryName ends with ".0".
+            if (strncmp(directoryName + (directoryNameLen - kPostfixLen), kPostfix, kPostfixLen) !=
+                0) {
+                return 0;
+            }
+
+            // Extract Version from "10.0.{Version}.0" and convert Version into an integer.
+            return atoi(directoryName + kPrefixLen);
+        }
+
+        class ScopedFileHandle final {
+          public:
+            explicit ScopedFileHandle(HANDLE handle) : mHandle(handle) {
+            }
+            ~ScopedFileHandle() {
+                if (mHandle != INVALID_HANDLE_VALUE) {
+                    ASSERT(FindClose(mHandle));
+                }
+            }
+            HANDLE GetHandle() const {
+                return mHandle;
+            }
+
+          private:
+            HANDLE mHandle;
+        };
+
+        std::string GetWindowsSDKBasePath() {
+            const char* kDefaultWindowsSDKPath =
+                "C:\\Program Files (x86)\\Windows Kits\\10\\bin\\*";
+            WIN32_FIND_DATAA fileData;
+            ScopedFileHandle handle(FindFirstFileA(kDefaultWindowsSDKPath, &fileData));
+            if (handle.GetHandle() == INVALID_HANDLE_VALUE) {
+                return "";
+            }
+
+            uint32_t highestWindowsSDKVersion = 0;
+            do {
+                if (!(fileData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)) {
+                    continue;
+                }
+
+                highestWindowsSDKVersion =
+                    std::max(highestWindowsSDKVersion,
+                             GetWindowsSDKVersionFromDirectoryName(fileData.cFileName));
+            } while (FindNextFileA(handle.GetHandle(), &fileData));
+
+            if (highestWindowsSDKVersion == 0) {
+                return "";
+            }
+
+            // Currently we only support using DXC on x64.
+            std::ostringstream ostream;
+            ostream << "C:\\Program Files (x86)\\Windows Kits\\10\\bin\\10.0."
+                    << highestWindowsSDKVersion << ".0\\x64\\";
+
+            return ostream.str();
+        }
+    }  // anonymous namespace
 
     PlatformFunctions::PlatformFunctions() {
     }
@@ -26,8 +108,7 @@ namespace dawn_native { namespace d3d12 {
     MaybeError PlatformFunctions::LoadFunctions() {
         DAWN_TRY(LoadD3D12());
         DAWN_TRY(LoadDXGI());
-        LoadDXIL();
-        LoadDXCompiler();
+        LoadDXCLibraries();
         DAWN_TRY(LoadFXCompiler());
         DAWN_TRY(LoadD3D11());
         LoadPIXRuntime();
@@ -74,17 +155,48 @@ namespace dawn_native { namespace d3d12 {
         return {};
     }
 
-    void PlatformFunctions::LoadDXIL() {
-        if (!mDXILLib.Open("dxil.dll", nullptr)) {
-            mDXILLib.Close();
-        }
+    void PlatformFunctions::LoadDXCLibraries() {
+        const std::string& windowsSDKBasePath = GetWindowsSDKBasePath();
+
+        LoadDXIL(windowsSDKBasePath);
+        LoadDXCompiler(windowsSDKBasePath);
     }
 
-    void PlatformFunctions::LoadDXCompiler() {
+    void PlatformFunctions::LoadDXIL(const std::string& baseWindowsSDKPath) {
+        const char* dxilDLLName = "dxil.dll";
+        const std::array<std::string, 2> kDxilDLLPaths = {
+            {dxilDLLName, baseWindowsSDKPath + dxilDLLName}};
+
+        for (const std::string& dxilDLLPath : kDxilDLLPaths) {
+            if (mDXILLib.Open(dxilDLLPath, nullptr)) {
+                return;
+            }
+        }
+        ASSERT(!mDXILLib.Valid());
+    }
+
+    void PlatformFunctions::LoadDXCompiler(const std::string& baseWindowsSDKPath) {
         // DXIL must be loaded before DXC, otherwise shader signing is unavailable
-        if (!mDXCompilerLib.Open("dxcompiler.dll", nullptr) ||
-            !mDXCompilerLib.GetProc(&dxcCreateInstance, "DxcCreateInstance", nullptr)) {
-            mDXCompilerLib.Close();
+        if (!mDXILLib.Valid()) {
+            return;
+        }
+
+        const char* dxCompilerDLLName = "dxcompiler.dll";
+        const std::array<std::string, 2> kDxCompilerDLLPaths = {
+            {dxCompilerDLLName, baseWindowsSDKPath + dxCompilerDLLName}};
+
+        DynamicLib dxCompilerLib;
+        for (const std::string& dxCompilerDLLName : kDxCompilerDLLPaths) {
+            if (dxCompilerLib.Open(dxCompilerDLLName, nullptr)) {
+                break;
+            }
+        }
+
+        if (dxCompilerLib.Valid() &&
+            dxCompilerLib.GetProc(&dxcCreateInstance, "DxcCreateInstance", nullptr)) {
+            mDXCompilerLib = std::move(dxCompilerLib);
+        } else {
+            mDXILLib.Close();
         }
     }
 

src/dawn_native/d3d12/PlatformFunctions.h

@@ -91,8 +91,9 @@ namespace dawn_native { namespace d3d12 {
         MaybeError LoadD3D12();
         MaybeError LoadD3D11();
         MaybeError LoadDXGI();
-        void LoadDXIL();
-        void LoadDXCompiler();
+        void LoadDXCLibraries();
+        void LoadDXIL(const std::string& baseWindowsSDKPath);
+        void LoadDXCompiler(const std::string& baseWindowsSDKPath);
         MaybeError LoadFXCompiler();
         void LoadPIXRuntime();