ltrace on FFI calls

I want to trace calls from a Haskell program to LLVM. I tried ltrace and latrace. latrace didn't trace anything useful and ltrace shows at least the call to one function (LLVMBuildRetVoid), but not the other ones. I'm quite confident that I linked to LLVM dynamically, since the executable is small (35 KB, not 60 MB as when linking statically). Do GHC-generated programs call a foreign library in a way that bypasses ltrace?