[pytorch/tensorexpr] Create LLJIT instance with an ObjectLinkingLayer (…

…pytorch#103824)

- Upstream LLVM switched LLJIT's default JIT linker for ELF/x86-64 to JITLink: [commit](llvm/llvm-project@b92839c). This commit mandates clients to use JITLink plugins, following the example in "llvm/examples/OrcV2Examples/LLJITWithCustomObjectLinkingLayer".

- Current change updates PytorchLLVMJITImpl to set ObjectLinkingLayer on LLJIT creation.
- If setObjectLinkingLayerCreator not set, RTDyldObjectLinkingLayer will be constructed. This is currently causing "Symbols not found: [ llvm_orc_registerEHFrameSectionWrapper ]" error for tests in test_quantization.py when pytorch is built to use latest LLVM.

Pull Request resolved: pytorch#103824
Approved by: https://github.com/jeffdaily, https://github.com/davidberard98

torch/csrc/jit/tensorexpr/llvm_jit.cpp

@@ -157,10 +157,19 @@ class TORCH_API PytorchLLVMJITImpl {
       c10::optional<std::string> attrs)
       : TM(assertSuccess(makeTargetMachineBuilder(triple, cpu, attrs)
                              .createTargetMachine())),
-        LLJ(assertSuccess(LLJITBuilder()
-                              .setJITTargetMachineBuilder(
-                                  makeTargetMachineBuilder(triple, cpu, attrs))
-                              .create())) {
+        LLJ(assertSuccess(
+            LLJITBuilder()
+                .setJITTargetMachineBuilder(
+                    makeTargetMachineBuilder(triple, cpu, attrs))
+#if LLVM_VERSION_MAJOR >= 17
+                .setObjectLinkingLayerCreator([&](ExecutionSession& ES,
+                                                  const Triple& TT) {
+                  return std::make_unique<ObjectLinkingLayer>(
+                      ES,
+                      assertSuccess(jitlink::InProcessMemoryManager::Create()));
+                })
+#endif
+                .create())) {
     auto ProcSymbolsGenerator =
         assertSuccess(DynamicLibrarySearchGenerator::GetForCurrentProcess(
             LLJ->getDataLayout().getGlobalPrefix()));