[clang] Fix early exit when finding hip dlls AMDGPUArchByHIP.cpp (PR #166238)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang

@llvm/pr-subscribers-backend-amdgpu

Author: None (harkgill-amd)

<details>
<summary>Changes</summary>

To find the greatest versioned `amdhip64_n.dll`, We iterate through `SearchPaths` and the files within each path. 

The `if (!DLLNames.empty())` check will return true if the first `SearchPath` contains a dll - this will result in the break statement executing and all other SearchPaths being skipped, potentially missing out on a greater versioned dll. 

Removing the check and break allows for all `SearchPaths` to get checked and `DLLNames` to cover the complete set of dlls presents. 

Also, the current `compareVersions` function was not removing the .dll portion of the VerStr resulting in incorrect comparisons between VtA and VtB. Updated the function to handle the case - test ouput is as follows (ignore SearchPath and DLLName logging).

```
offload-arch.exe
SearchPath: C:\Users\rocm\harry\llvm-project\build\Debug\bin
SearchPath: C:\Windows\system32
SearchPath: C:\Windows
SearchPath: C:\Windows\system32
SearchPath: C:\Windows
SearchPath: C:\Windows\System32\Wbem
SearchPath: C:\Windows\System32\WindowsPowerShell\v1.0\
SearchPath: C:\Windows\System32\OpenSSH\
SearchPath: C:\Program Files\Git\cmd
SearchPath: C:\Program Files\CMake\bin
SearchPath: C:\Program Files (x86)\Windows Kits\10\Windows Performance Toolkit\
SearchPath: C:\Users\rocm\harry\.venv\Lib\site-packages\_rocm_sdk_core\bin
SearchPath: C:\Users\rocm\AppData\Local\Microsoft\WindowsApps
SearchPath:
DLLName: C:/Windows/system32/amdhip64_6.dll
DLLName: C:/Windows/system32/amdhip64_7.dll
DLLName: C:/Windows/system32/amdhip64_6.dll
DLLName: C:/Windows/system32/amdhip64_7.dll
DLLName: C:/Users/rocm/harry/.venv/Lib/site-packages/_rocm_sdk_core/bin/amdhip64_7.dll
HIP Library Path: C:\Windows\system32\amdhip64_7.dll
gfx1151

---
Full diff: https://github.com/llvm/llvm-project/pull/166238.diff


1 Files Affected:

- (modified) clang/tools/offload-arch/AMDGPUArchByHIP.cpp (+10-4) 


``````````diff
diff --git a/clang/tools/offload-arch/AMDGPUArchByHIP.cpp b/clang/tools/offload-arch/AMDGPUArchByHIP.cpp
index 11cff4f5ecdbe..ff39a85d15628 100644
--- a/clang/tools/offload-arch/AMDGPUArchByHIP.cpp
+++ b/clang/tools/offload-arch/AMDGPUArchByHIP.cpp
@@ -98,8 +98,16 @@ static std::vector<std::string> getSearchPaths() {
 // Custom comparison function for dll name
 static bool compareVersions(StringRef A, StringRef B) {
   auto ParseVersion = [](StringRef S) -> VersionTuple {
-    size_t Pos = S.find_last_of('_');
-    StringRef VerStr = (Pos == StringRef::npos) ? S : S.substr(Pos + 1);
+    StringRef Filename = sys::path::filename(S);
+    size_t Pos = Filename.find_last_of('_');
+    if (Pos == StringRef::npos)
+      return VersionTuple();
+
+    StringRef VerStr = Filename.substr(Pos + 1);
+    size_t DotPos = VerStr.find('.');
+    if (DotPos != StringRef::npos)
+      VerStr = VerStr.substr(0, DotPos);
+
     VersionTuple Vt;
     (void)Vt.tryParse(VerStr);
     return Vt;
@@ -135,8 +143,6 @@ static std::pair<std::string, bool> findNewestHIPDLL() {
           Filename.ends_with(HipDLLSuffix))
         DLLNames.push_back(sys::path::convert_to_slash(DirIt->path()));
     }
-    if (!DLLNames.empty())
-      break;
   }
 
   if (DLLNames.empty())

``````````

</details>


https://github.com/llvm/llvm-project/pull/166238