Function module_mangled_symbol 

pub fn module_mangled_symbol(
    base: &str,
    crate_hash: &str,
    module_path: &str,
) -> String

mangled_symbol further qualified by the defining module, for wasm symbols of items that may share a name across modules of one crate. The macro only learns the module path from rustc, so it emits this as concat!(module_mangled_symbol(base, hash, ""), module_path!()).