[SYCL] Add fallback support for KernelCompiler loading of ocloc (#18245)

Presently, the KernelCompiler just tries to load whatever ocloc shared
library is in the environment. And if it doesn't find a compatible one,
then it reports that OpenCL C compilation is not supported. But on
Windows this should be more robust, so we are adding fallback support.
If the ocloc shared library in the environment isn't compatible, try the
one in the OneAPI installation.

Signed-off-by: Chris Perkins <[email protected]>

Author: cperkinsintel

sycl/source/detail/kernel_compiler/kernel_compiler_opencl.cpp

@@ -70,28 +70,40 @@ static std::unique_ptr<void, std::function<void(void *)>>
 
 void loadOclocLibrary(const std::vector<uint32_t> &IPVersionVec) {
 #ifdef __SYCL_RT_OS_WINDOWS
-  static const std::string OclocPath = "ocloc64.dll";
+  // first the environment, if not compatible will move on to absolute path.
+  static const std::vector<std::string> OclocPaths = {
+      "ocloc64.dll",
+      "C:\\Program Files (x86)\\Intel\\oneAPI\\ocloc\\latest\\ocloc64.dll"};
 #else
-  static const std::string OclocPath = "libocloc.so";
+  static const std::vector<std::string> OclocPaths = {"libocloc.so"};
 #endif
 
-  // set OclocLibrary value by side effect.
-  try {
-    // Load then perform checks. Each check throws.
-    void *tempPtr = sycl::detail::ur::loadOsLibrary(OclocPath);
-    OclocLibrary.reset(tempPtr);
+  // attemptLoad() sets OclocLibrary value by side effect.
+  auto attemptLoad = [&](std::string OclocPath) {
+    try {
+      // Load then perform checks. Each check throws.
+      void *tempPtr = sycl::detail::ur::loadOsLibrary(OclocPath);
+      OclocLibrary.reset(tempPtr);
 
-    if (tempPtr == nullptr)
-      throw sycl::exception(make_error_code(errc::build),
-                            "Unable to load ocloc from " + OclocPath);
+      if (tempPtr == nullptr)
+        throw sycl::exception(make_error_code(errc::build),
+                              "Unable to load ocloc from " + OclocPath);
 
-    checkOclocLibrary(tempPtr);
+      checkOclocLibrary(tempPtr);
 
-    InvokeOclocQuery(IPVersionVec, "CL_DEVICE_OPENCL_C_ALL_VERSIONS");
-  } catch (const sycl::exception &) {
-    OclocLibrary.reset(nullptr);
-    std::rethrow_exception(std::current_exception());
+      InvokeOclocQuery(IPVersionVec, "CL_DEVICE_OPENCL_C_ALL_VERSIONS");
+    } catch (const sycl::exception &) {
+      OclocLibrary.reset(nullptr);
+      return false;
+    }
+    return true;
+  };
+  for (auto result : OclocPaths) {
+    if (attemptLoad(result))
+      return; // exit on successful attempt
   }
+  // If we haven't exited yet, then throw to indicate failure.
+  throw sycl::exception(make_error_code(errc::build), "Unable to load ocloc");
 }
 
 bool OpenCLC_Compilation_Available(const std::vector<uint32_t> &IPVersionVec) {