use rustc_hir::LangItem; use rustc_middle::ty::subst::GenericArg; use rustc_middle::ty::AssocKind; use rustc_session::config::{sigpipe, EntryFnType}; use rustc_span::symbol::Ident; use crate::prelude::*; /// Create the `main` function which will initialize the rust runtime and call /// users main function. pub(crate) fn maybe_create_entry_wrapper( tcx: TyCtxt<'_>, module: &mut impl Module, unwind_context: &mut UnwindContext, is_jit: bool, is_primary_cgu: bool, ) { let (main_def_id, (is_main_fn, sigpipe)) = match tcx.entry_fn(()) { Some((def_id, entry_ty)) => ( def_id, match entry_ty { EntryFnType::Main { sigpipe } => (true, sigpipe), EntryFnType::Start => (false, sigpipe::DEFAULT), }, ), None => return, }; if main_def_id.is_local() { let instance = Instance::mono(tcx, main_def_id).polymorphize(tcx); if !is_jit && module.get_name(&*tcx.symbol_name(instance).name).is_none() { return; } } else if !is_primary_cgu { return; } create_entry_fn(tcx, module, unwind_context, main_def_id, is_jit, is_main_fn, sigpipe); fn create_entry_fn( tcx: TyCtxt<'_>, m: &mut impl Module, unwind_context: &mut UnwindContext, rust_main_def_id: DefId, ignore_lang_start_wrapper: bool, is_main_fn: bool, sigpipe: u8, ) { let main_ret_ty = tcx.fn_sig(rust_main_def_id).no_bound_vars().unwrap().output(); // Given that `main()` has no arguments, // then its return type cannot have // late-bound regions, since late-bound // regions must appear in the argument // listing. let main_ret_ty = tcx.normalize_erasing_regions( ty::ParamEnv::reveal_all(), main_ret_ty.no_bound_vars().unwrap(), ); let cmain_sig = Signature { params: vec![ AbiParam::new(m.target_config().pointer_type()), AbiParam::new(m.target_config().pointer_type()), ], returns: vec![AbiParam::new(m.target_config().pointer_type() /*isize*/)], call_conv: crate::conv_to_call_conv( tcx.sess, tcx.sess.target.options.entry_abi, m.target_config().default_call_conv, ), }; let entry_name = tcx.sess.target.options.entry_name.as_ref(); let cmain_func_id = match m.declare_function(entry_name, Linkage::Export, &cmain_sig) { Ok(func_id) => func_id, Err(err) => { tcx.sess .fatal(&format!("entry symbol `{entry_name}` declared multiple times: {err}")); } }; let instance = Instance::mono(tcx, rust_main_def_id).polymorphize(tcx); let main_name = tcx.symbol_name(instance).name; let main_sig = get_function_sig(tcx, m.target_config().default_call_conv, instance); let main_func_id = m.declare_function(main_name, Linkage::Import, &main_sig).unwrap(); let mut ctx = Context::new(); ctx.func.signature = cmain_sig; { let mut func_ctx = FunctionBuilderContext::new(); let mut bcx = FunctionBuilder::new(&mut ctx.func, &mut func_ctx); let block = bcx.create_block(); bcx.switch_to_block(block); let arg_argc = bcx.append_block_param(block, m.target_config().pointer_type()); let arg_argv = bcx.append_block_param(block, m.target_config().pointer_type()); let arg_sigpipe = bcx.ins().iconst(types::I8, sigpipe as i64); let main_func_ref = m.declare_func_in_func(main_func_id, &mut bcx.func); 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 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)]), ) .unwrap() .unwrap() .polymorphize(tcx); let report_name = tcx.symbol_name(report).name; let report_sig = get_function_sig(tcx, m.target_config().default_call_conv, 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); let res = bcx.func.dfg.inst_results(report_call_inst)[0]; match m.target_config().pointer_type() { types::I32 => res, types::I64 => bcx.ins().sextend(types::I64, res), _ => unimplemented!("16bit systems are not yet supported"), } } else if is_main_fn { let start_def_id = tcx.require_lang_item(LangItem::Start, None); let start_instance = Instance::resolve( tcx, ParamEnv::reveal_all(), start_def_id, tcx.mk_substs(&[main_ret_ty.into()]), ) .unwrap() .unwrap() .polymorphize(tcx); let start_func_id = import_function(tcx, m, start_instance); let main_val = bcx.ins().func_addr(m.target_config().pointer_type(), main_func_ref); let func_ref = m.declare_func_in_func(start_func_id, &mut bcx.func); let call_inst = bcx.ins().call(func_ref, &[main_val, arg_argc, arg_argv, arg_sigpipe]); bcx.inst_results(call_inst)[0] } else { // using user-defined start fn let call_inst = bcx.ins().call(main_func_ref, &[arg_argc, arg_argv]); bcx.inst_results(call_inst)[0] }; bcx.ins().return_(&[result]); bcx.seal_all_blocks(); bcx.finalize(); } if let Err(err) = m.define_function(cmain_func_id, &mut ctx) { tcx.sess.fatal(&format!("entry symbol `{entry_name}` defined multiple times: {err}")); } unwind_context.add_function(cmain_func_id, &ctx, m.isa()); } }