I'm creating a simple MCJIT based JIT (implementing Kaleidoscope tutorial in Rust to be more precise). I'm using SectionMemoryManager::getSymbolAddress for symbol resolution. It sees symbols from libraries (e.g. sin function), but fails to resolve functions from my program (global, visible with nm, marked there by T). Is this the expected behavior? Or should it be some error in my code?
If this is the expected behavior, how should I properly resolve symbols from the current process? I'm adding symbols from the process with LLVMAddSymbol now, so resolution starts to work. Is this the right solution?
For those, who'll read my code. The problem with symbols is not related with the name mangling, as when I tried to make SectionMemoryManager::getSymbolAddress work, I used no_mangle directive, so they were named properly.
Thanks to Lang Hames, he has answered my question in other place. I cite the answer here for the case if somebody will look at the same problem as me:
In answer to your question: SectionMemoryManager::getSymbolAddress eventually (through the RTDyldMemoryManager base class) makes a call to llvm::sys::DynamicLibrary::SearchForAddressOfSymbol, which searches all previously loaded dynamic libraries for the symbol. You can call to llvm::sys::DynamicLibrary::LoadLibraryPermanently(nullptr) as part of your JIT initialisation (before any calls to getSymbolAddress) to import the program's symbols into DynamicLibrary's symbol tables.
If you really want to expose all functions in your program to the JIT'd code this is a good way to go. If you only want to expose a limited set of runtime functions you can put them in a shared library and just load that.