[clang] [offload-arch] Fix amdgpu HIP DLL search path on Windows (PR #209898)

[Scott Todd via cfe-commits]

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@@ -25,6 +32,37 @@ cl::opt<bool> Verbose("offload-arch-test-verbose", cl::Hidden, cl::init(false));
 
 #ifdef _WIN32
 
+// --- primeLibraryLoad ---
+
+namespace {
+std::wstring CapturedPath;
+HANDLE CapturedFile;
+DWORD CapturedFlags;
+
+HMODULE WINAPI mockLoadLibraryExW(LPCWSTR Path, HANDLE File, DWORD Flags) {
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ScottTodd wrote:

That isn't built to be reused by other tests though, and it looks pretty heavy to fork for this. I think it would be more appropriate to test that `offload-arch` itself functions as expected in the presence of `amdhip64_*.dll` on amdgpu runners. Is that something we can test for here in llvm/llvm-project? We will definitely test it in ROCm/TheRock at least...

https://github.com/llvm/llvm-project/pull/209898