shadow-stack and llvm_gc_root_chain linkage when using JIT

What is the expected way of gaining access to llvm_gc_root_chain when using JIT?

The only way I could figure out was this:

fpm->add(llvm::createShadowStackGCLoweringPass());
fpm->doInitialization();
fpm->run(*f);
// EPIC KLUDGE
auto wrong = _module->getNamedGlobal(“llvm_gc_root_chain”);
auto right = new llvm::GlobalVariable(
*_module.get(),
wrong->getType()->getContainedType(0),
false, // variable
llvm::GlobalVariable::ExternalLinkage,
nullptr,
“my_gc_root_chain”);
wrong->replaceAllUsesWith(right);

…which works, has a bit of a smell about it.

I cannot use the LLVM’s definition from my GC because this is running in JIT.

I gave up trying to give it external linkage before shadow-stack-gc-lowering-pass since it makes a unique struct type that I cannot match (or I’m misunderstanding something badly), causing Stores to fail when using my definition.

Cheers,

– nikodemus