Function linking_symbol_name_for_instance_in_crate 

pub(crate) fn linking_symbol_name_for_instance_in_crate<'tcx>(
    tcx: TyCtxt<'tcx>,
    symbol: ExportedSymbol<'tcx>,
    export_kind: SymbolExportKind,
    instantiating_crate: CrateNum,
) -> String

This is the symbol name of the given instance as seen by the linker.

On 32-bit Windows symbols are decorated according to their calling conventions.