Use wide char version of Windows API (#8390)

This PR modernizes the Windows-specific code by replacing ANSI Windows
API functions with their Unicode (wide character) counterparts. This
change ensures proper handling of Unicode file paths and strings on
Windows systems.

### File Operations (`source/core/slang-io.cpp`)
- `DeleteFileA` → `DeleteFileW`
- `GetTempPathA` → `GetTempPathW` 
- `GetTempFileNameA` → `GetTempFileNameW`
- `RemoveDirectoryA` → `RemoveDirectoryW`
- `SHFileOperationA` → `SHFileOperationW`
- `GetModuleFileNameA` → `GetModuleFileNameW` with UTF-8 conversion

### Platform Operations (`source/core/slang-platform.cpp`)
- `GetModuleHandleExA` → `GetModuleHandleExW`
- `LoadLibraryExA` → `LoadLibraryExW`
- `LoadLibraryA` → `LoadLibraryW`
- `OutputDebugStringA` → `OutputDebugStringW`

### Runtime and Tools
- `MessageBoxA` → `MessageBoxW` in slang-rt
- `GetCurrentDirectoryA` → `GetCurrentDirectoryW` in slang-fiddle
- String literal conversion to wide strings in vk-pipeline-create

---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Gangzheng Tong <gtong-nv@users.noreply.github.com>
Co-authored-by: slangbot <ellieh+slangbot@nvidia.com>
Co-authored-by: slangbot <186143334+slangbot@users.noreply.github.com>

1 files changed, 10 insertions, 7 deletions

diff --git a/source/core/slang-platform.cpp b/source/core/slang-platform.cpp
index 25e6bc6f0..75c1b96cd 100644
--- a/source/core/slang-platform.cpp
+++ b/source/core/slang-platform.cpp
@@ -122,7 +122,7 @@ SLANG_COMPILE_TIME_ASSERT(E_OUTOFMEMORY == SLANG_E_OUT_OF_MEMORY);
     handleOut = nullptr;
     if (!platformFileName || strlen(platformFileName) == 0)
     {
-        if (!GetModuleHandleExA(0, nullptr, (HMODULE*)&handleOut))
+        if (!GetModuleHandleExW(0, nullptr, (HMODULE*)&handleOut))
             return SLANG_FAIL;
         return SLANG_OK;
     }
@@ -131,12 +131,14 @@ SLANG_COMPILE_TIME_ASSERT(E_OUTOFMEMORY == SLANG_E_OUT_OF_MEMORY);
     // First attempt tries on the directories explicitly specified with AddDllDirectory(),
     // If it failed to find one, we will search over all PATH.
     // Windows API made two approaches mutually exclusive and we need to try two times.
-    // https://learn.microsoft.com/en-us/windows/win32/api/libloaderapi/nf-libloaderapi-loadlibraryexa
-    HMODULE h = LoadLibraryExA(platformFileName, nullptr, LOAD_LIBRARY_SEARCH_USER_DIRS);
-    // If LoadLibraryExA failed, try again with LoadLibraryA.
-    // https://docs.microsoft.com/en-us/windows/desktop/api/libloaderapi/nf-libloaderapi-loadlibrarya
+    // https://learn.microsoft.com/en-us/windows/win32/api/libloaderapi/nf-libloaderapi-loadlibraryexw
+    String platformFileNameStr(platformFileName);
+    HMODULE h =
+        LoadLibraryExW(platformFileNameStr.toWString(), nullptr, LOAD_LIBRARY_SEARCH_USER_DIRS);
+    // If LoadLibraryExW failed, try again with LoadLibraryW.
+    // https://docs.microsoft.com/en-us/windows/desktop/api/libloaderapi/nf-libloaderapi-loadlibraryw
     if (!h)
-        h = LoadLibraryA(platformFileName);
+        h = LoadLibraryW(platformFileNameStr.toWString());
     // If still not found, return an error.
     if (!h)
     {
@@ -356,7 +358,8 @@ static const PlatformFlags s_familyFlags[int(PlatformFamily::CountOf)] = {
 /* static */ SlangResult PlatformUtil::outputDebugMessage([[maybe_unused]] const char* text)
 {
 #ifdef _WIN32
-    OutputDebugStringA(text);
+    String textStr(text);
+    OutputDebugStringW(textStr.toWString());
     return SLANG_OK;
 #else
     return SLANG_E_NOT_AVAILABLE;