[llvm] [Offload] Try to load Level Zero loader with version suffix (PR #180042)

[Alex Duran via llvm-commits]

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@@ -111,6 +111,24 @@ static bool loadLevelZero() {
   ODBG(OLDT_Init) << "Trying to load " << L0Library;
   auto DynlibHandle = std::make_unique<llvm::sys::DynamicLibrary>(
       llvm::sys::DynamicLibrary::getPermanentLibrary(L0Library, &ErrMsg));
+#ifndef _WIN32
+  if (!DynlibHandle->isValid()) {
+    // Try to open loader with major version number. It is repeated from the
+    // current version down to 1.
+    std::string LoaderName{LEVEL_ZERO_LIBRARY};
+    LoaderName += ".";
+    constexpr int MinZeVersion{1};
+    int CurrVersion = ZE_MAJOR_VERSION(ZE_API_VERSION_CURRENT);
+    for (int I = CurrVersion; I >= MinZeVersion && !DynlibHandle->isValid();
+         I--) {
+      std::string LoaderVer{LoaderName + std::to_string(I)};
+      ODBG(OLDT_Init) << "Trying to load " << LoaderVer;
+      DynlibHandle = std::make_unique<llvm::sys::DynamicLibrary>(
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adurang wrote:

If the ABI would change for the APIs that we use, it wouldn't compile without a source change.
If a source change is needed, then minVersion number needs to be bumped, so I feel l this is correct.

https://github.com/llvm/llvm-project/pull/180042