message: Call Termination::report on main result in jit mode
diff: use cranelift_codegen::binemit::{NullStackMapSink, NullTrapSink};
  use rustc_hir::LangItem;
  +use rustc_middle::ty::subst::GenericArg;
  +use rustc_middle::ty::AssocKind;
  use rustc_session::config::EntryFnType;
  +use rustc_span::symbol::Ident;
  use crate::prelude::*;
  @@ -79,8 +82,38 @@ fn create_entry_fn(
  let result = if is_main_fn && ignore_lang_start_wrapper {
  // regular main fn, but ignoring #[lang = "start"] as we are running in the jit
  // FIXME set program arguments somehow
  - bcx.ins().call(main_func_ref, &[]);
  - bcx.ins().iconst(m.target_config().pointer_type(), 0)
  + let call_inst = bcx.ins().call(main_func_ref, &[]);
  + let call_results = bcx.func.dfg.inst_results(call_inst).to_owned();
  +
  + let termination_trait = tcx.require_lang_item(LangItem::Termination, None);
  + let report = tcx
  + .associated_items(termination_trait)
  + .find_by_name_and_kind(
  + tcx,
  + Ident::from_str("report"),
  + AssocKind::Fn,
  + termination_trait,
  + )
  + .unwrap();
  + let report = Instance::resolve(
  + tcx,
  + ParamEnv::reveal_all(),
  + report.def_id,
  + tcx.mk_substs([GenericArg::from(main_ret_ty)].iter()),
  + )
  + .unwrap()
  + .unwrap();
  +
  + let report_name = tcx.symbol_name(report).name;
  + let report_sig = get_function_sig(tcx, m.isa().triple(), report);
  + let report_func_id =
  + m.declare_function(report_name, Linkage::Import, &report_sig).unwrap();
  + let report_func_ref = m.declare_func_in_func(report_func_id, &mut bcx.func);
  +
  + // FIXME do proper abi handling instead of expecting the pass mode to be identical
  + // for returns and arguments.
  + let report_call_inst = bcx.ins().call(report_func_ref, &call_results);
  + bcx.func.dfg.inst_results(report_call_inst)[0]
  } else if is_main_fn {
  let start_def_id = tcx.require_lang_item(LangItem::Start, None);
  let start_instance = Instance::resolve(
  