IRGen: Reinstate JIT workaround removed in PR #28704

The usage of private vars that seemingly are accessed accross object
files confuses the JIT.

rdar://59782487

Author: aschwaighofer

lib/IRGen/GenDecl.cpp

@@ -2667,7 +2667,10 @@ static llvm::GlobalVariable *createGOTEquivalent(IRGenModule &IGM,
 
   // rdar://problem/53836960: i386 ld64 also mis-links relative references
   // to GOT entries.
-  if (!IGM.Triple.isOSDarwin() || IGM.Triple.getArch() != llvm::Triple::x86) {
+  // rdar://problem/59782487: issue with on-device JITd expressions.
+  // The JIT gets confused by private vars accessed accross object files.
+  if (!IGM.getOptions().UseJIT &&
+      (!IGM.Triple.isOSDarwin() || IGM.Triple.getArch() != llvm::Triple::x86)) {
     gotEquivalent->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
   } else {
     ApplyIRLinkage(IRLinkage::InternalLinkOnceODR)