src/abi.rs

   1 use std::iter;
   2
   3 use rustc::hir;
   4 use rustc_target::spec::abi::Abi;
   5
   6 use crate::prelude::*;
   7
   8 pub fn cton_sig_from_fn_ty<'a, 'tcx: 'a>(
   9     tcx: TyCtxt<'a, 'tcx, 'tcx>,
  10     fn_ty: Ty<'tcx>,
  11 ) -> Signature {
  12     let sig = ty_fn_sig(tcx, fn_ty);
  13     assert!(!sig.variadic, "Variadic function are not yet supported");
  14     let (call_conv, inputs, _output): (CallConv, Vec<Ty>, Ty) = match sig.abi {
  15         Abi::Rust => (CallConv::Fast, sig.inputs().to_vec(), sig.output()),
  16         Abi::C => (CallConv::SystemV, sig.inputs().to_vec(), sig.output()),
  17         Abi::RustCall => {
  18             println!(
  19                 "rust-call sig: {:?} inputs: {:?} output: {:?}",
  20                 sig,
  21                 sig.inputs(),
  22                 sig.output()
  23             );
  24             assert_eq!(sig.inputs().len(), 2);
  25             let extra_args = match sig.inputs().last().unwrap().sty {
  26                 ty::TyTuple(ref tupled_arguments) => tupled_arguments,
  27                 _ => bug!("argument to function with \"rust-call\" ABI is not a tuple"),
  28             };
  29             let mut inputs: Vec<Ty> = vec![sig.inputs()[0]];
  30             inputs.extend(extra_args.into_iter());
  31             (CallConv::Fast, inputs, sig.output())
  32         }
  33         Abi::System => bug!("system abi should be selected elsewhere"),
  34         Abi::RustIntrinsic => (CallConv::SystemV, sig.inputs().to_vec(), sig.output()),
  35         _ => unimplemented!("unsupported abi {:?}", sig.abi),
  36     };
  37     Signature {
  38         params: Some(types::I64).into_iter() // First param is place to put return val
  39             .chain(inputs.into_iter().map(|ty| {
  40                 let cton_ty = cton_type_from_ty(tcx, ty);
  41                 if let Some(cton_ty) = cton_ty {
  42                     cton_ty
  43                 } else {
  44                     if sig.abi == Abi::C {
  45                         unimplemented!("Non scalars are not yet supported for \"C\" abi");
  46                     }
  47                     types::I64
  48                 }
  49             }))
  50             .map(AbiParam::new).collect(),
  51         returns: vec![],
  52         call_conv,
  53         argument_bytes: None,
  54     }
  55 }
  56
  57 fn ty_fn_sig<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, ty: Ty<'tcx>) -> ty::FnSig<'tcx> {
  58     let sig = match ty.sty {
  59         ty::TyFnDef(..) |
  60         // Shims currently have type TyFnPtr. Not sure this should remain.
  61         ty::TyFnPtr(_) => ty.fn_sig(tcx),
  62         ty::TyClosure(def_id, substs) => {
  63             let sig = substs.closure_sig(def_id, tcx);
  64
  65             let env_ty = tcx.closure_env_ty(def_id, substs).unwrap();
  66             sig.map_bound(|sig| tcx.mk_fn_sig(
  67                 iter::once(*env_ty.skip_binder()).chain(sig.inputs().iter().cloned()),
  68                 sig.output(),
  69                 sig.variadic,
  70                 sig.unsafety,
  71                 sig.abi
  72             ))
  73         }
  74         ty::TyGenerator(def_id, substs, _) => {
  75             let sig = substs.poly_sig(def_id, tcx);
  76
  77             let env_region = ty::ReLateBound(ty::INNERMOST, ty::BrEnv);
  78             let env_ty = tcx.mk_mut_ref(tcx.mk_region(env_region), ty);
  79
  80             sig.map_bound(|sig| {
  81                 let state_did = tcx.lang_items().gen_state().unwrap();
  82                 let state_adt_ref = tcx.adt_def(state_did);
  83                 let state_substs = tcx.intern_substs(&[
  84                     sig.yield_ty.into(),
  85                     sig.return_ty.into(),
  86                 ]);
  87                 let ret_ty = tcx.mk_adt(state_adt_ref, state_substs);
  88
  89                 tcx.mk_fn_sig(iter::once(env_ty),
  90                     ret_ty,
  91                     false,
  92                     hir::Unsafety::Normal,
  93                     Abi::Rust
  94                 )
  95             })
  96         }
  97         _ => bug!("unexpected type {:?} to ty_fn_sig", ty)
  98     };
  99     tcx.normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), &sig)
 100 }
 101
 102 impl<'a, 'tcx: 'a> FunctionCx<'a, 'tcx> {
 103     /// Instance must be monomorphized
 104     pub fn get_function_ref(&mut self, inst: Instance<'tcx>) -> FuncRef {
 105         assert!(!inst.substs.needs_infer() && !inst.substs.has_param_types());
 106         let fn_ty = inst.ty(self.tcx);
 107         let sig = cton_sig_from_fn_ty(self.tcx, fn_ty);
 108         let def_path_based_names =
 109             ::rustc_mir::monomorphize::item::DefPathBasedNames::new(self.tcx, false, false);
 110         let mut name = String::new();
 111         def_path_based_names.push_instance_as_string(inst, &mut name);
 112         let func_id = self
 113             .module
 114             .declare_function(&name, Linkage::Import, &sig)
 115             .unwrap();
 116         self.module
 117             .declare_func_in_func(func_id, &mut self.bcx.func)
 118     }
 119
 120     fn lib_call(
 121         &mut self,
 122         name: &str,
 123         input_tys: Vec<types::Type>,
 124         output_ty: Option<types::Type>,
 125         args: &[Value],
 126     ) -> Option<Value> {
 127         let sig = Signature {
 128             params: input_tys.iter().cloned().map(AbiParam::new).collect(),
 129             returns: vec![AbiParam::new(output_ty.unwrap_or(types::VOID))],
 130             call_conv: CallConv::SystemV,
 131             argument_bytes: None,
 132         };
 133         let func_id = self
 134             .module
 135             .declare_function(&name, Linkage::Import, &sig)
 136             .unwrap();
 137         let func_ref = self
 138             .module
 139             .declare_func_in_func(func_id, &mut self.bcx.func);
 140         let call_inst = self.bcx.ins().call(func_ref, args);
 141         if output_ty.is_none() {
 142             return None;
 143         }
 144         let results = self.bcx.inst_results(call_inst);
 145         assert_eq!(results.len(), 1);
 146         Some(results[0])
 147     }
 148
 149     pub fn easy_call(
 150         &mut self,
 151         name: &str,
 152         args: &[CValue<'tcx>],
 153         return_ty: Ty<'tcx>,
 154     ) -> CValue<'tcx> {
 155         let (input_tys, args): (Vec<_>, Vec<_>) = args
 156             .into_iter()
 157             .map(|arg| {
 158                 (
 159                     self.cton_type(arg.layout().ty).unwrap(),
 160                     arg.load_value(self),
 161                 )
 162             }).unzip();
 163         let return_layout = self.layout_of(return_ty);
 164         let return_ty = if let TypeVariants::TyTuple(tup) = return_ty.sty {
 165             if !tup.is_empty() {
 166                 bug!("easy_call( (...) -> <non empty tuple> ) is not allowed");
 167             }
 168             None
 169         } else {
 170             Some(self.cton_type(return_ty).unwrap())
 171         };
 172         if let Some(val) = self.lib_call(name, input_tys, return_ty, &args) {
 173             CValue::ByVal(val, return_layout)
 174         } else {
 175             CValue::ByRef(self.bcx.ins().iconst(types::I64, 0), return_layout)
 176         }
 177     }
 178
 179     fn self_sig(&self) -> FnSig<'tcx> {
 180         ty_fn_sig(self.tcx, self.instance.ty(self.tcx))
 181     }
 182
 183     fn return_type(&self) -> Ty<'tcx> {
 184         self.self_sig().output()
 185     }
 186 }
 187
 188 pub fn codegen_fn_prelude<'a, 'tcx: 'a>(fx: &mut FunctionCx<'a, 'tcx>, start_ebb: Ebb) {
 189     match fx.self_sig().abi {
 190         Abi::Rust | Abi::RustCall => {}
 191         _ => unimplemented!("declared function with non \"rust\" or \"rust-call\" abi"),
 192     }
 193
 194     let ret_param = fx.bcx.append_ebb_param(start_ebb, types::I64);
 195     let _ = fx.bcx.create_stack_slot(StackSlotData {
 196         kind: StackSlotKind::ExplicitSlot,
 197         size: 0,
 198         offset: None,
 199     }); // Dummy stack slot for debugging
 200
 201     enum ArgKind {
 202         Normal(Value),
 203         Spread(Vec<Value>),
 204     }
 205
 206     let func_params = fx.mir.args_iter().map(|local| {
 207         let arg_ty = fx.monomorphize(&fx.mir.local_decls[local].ty);
 208
 209         // Adapted from https://github.com/rust-lang/rust/blob/145155dc96757002c7b2e9de8489416e2fdbbd57/src/librustc_codegen_llvm/mir/mod.rs#L442-L482
 210         if Some(local) == fx.mir.spread_arg {
 211             // This argument (e.g. the last argument in the "rust-call" ABI)
 212             // is a tuple that was spread at the ABI level and now we have
 213             // to reconstruct it into a tuple local variable, from multiple
 214             // individual function arguments.
 215
 216             let tupled_arg_tys = match arg_ty.sty {
 217                 ty::TyTuple(ref tys) => tys,
 218                 _ => bug!("spread argument isn't a tuple?! but {:?}", arg_ty),
 219             };
 220
 221             let mut ebb_params = Vec::new();
 222             for arg_ty in tupled_arg_tys.iter() {
 223                 let cton_type = fx.cton_type(arg_ty).unwrap_or(types::I64);
 224                 ebb_params.push(fx.bcx.append_ebb_param(start_ebb, cton_type));
 225             }
 226
 227             (local, ArgKind::Spread(ebb_params), arg_ty)
 228         } else {
 229             let cton_type = fx.cton_type(arg_ty).unwrap_or(types::I64);
 230             (local, ArgKind::Normal(fx.bcx.append_ebb_param(start_ebb, cton_type)), arg_ty)
 231         }
 232     }).collect::<Vec<(Local, ArgKind, Ty)>>();
 233
 234     let ret_layout = fx.layout_of(fx.return_type());
 235     fx.local_map
 236         .insert(RETURN_PLACE, CPlace::Addr(ret_param, ret_layout));
 237
 238     for (local, arg_kind, ty) in func_params {
 239         let layout = fx.layout_of(ty);
 240         let stack_slot = fx.bcx.create_stack_slot(StackSlotData {
 241             kind: StackSlotKind::ExplicitSlot,
 242             size: layout.size.bytes() as u32,
 243             offset: None,
 244         });
 245
 246         let place = CPlace::from_stack_slot(fx, stack_slot, ty);
 247
 248         match arg_kind {
 249             ArgKind::Normal(ebb_param) => {
 250                 if fx.cton_type(ty).is_some() {
 251                     place.write_cvalue(fx, CValue::ByVal(ebb_param, place.layout()));
 252                 } else {
 253                     place.write_cvalue(fx, CValue::ByRef(ebb_param, place.layout()));
 254                 }
 255             }
 256             ArgKind::Spread(ebb_params) => {
 257                 for (i, ebb_param) in ebb_params.into_iter().enumerate() {
 258                     let sub_place = place.place_field(fx, mir::Field::new(i));
 259                     if fx.cton_type(sub_place.layout().ty).is_some() {
 260                         sub_place.write_cvalue(fx, CValue::ByVal(ebb_param, sub_place.layout()));
 261                     } else {
 262                         sub_place.write_cvalue(fx, CValue::ByRef(ebb_param, sub_place.layout()));
 263                     }
 264                 }
 265             }
 266         }
 267         fx.local_map.insert(local, place);
 268     }
 269
 270     for local in fx.mir.vars_and_temps_iter() {
 271         let ty = fx.mir.local_decls[local].ty;
 272         let layout = fx.layout_of(ty);
 273         let stack_slot = fx.bcx.create_stack_slot(StackSlotData {
 274             kind: StackSlotKind::ExplicitSlot,
 275             size: layout.size.bytes() as u32,
 276             offset: None,
 277         });
 278         let place = CPlace::from_stack_slot(fx, stack_slot, ty);
 279         fx.local_map.insert(local, place);
 280     }
 281 }
 282
 283 pub fn codegen_call<'a, 'tcx: 'a>(
 284     fx: &mut FunctionCx<'a, 'tcx>,
 285     func: &Operand<'tcx>,
 286     args: &[Operand<'tcx>],
 287     destination: &Option<(Place<'tcx>, BasicBlock)>,
 288 ) {
 289     let func = trans_operand(fx, func);
 290     let fn_ty = func.layout().ty;
 291     let sig = ty_fn_sig(fx.tcx, fn_ty);
 292
 293     let return_place = destination.as_ref().map(|(place, _)| trans_place(fx, place));
 294
 295     // Unpack arguments tuple for closures
 296     let args = if sig.abi == Abi::RustCall {
 297         assert_eq!(args.len(), 2, "rust-call abi requires two arguments");
 298         let self_arg = trans_operand(fx, &args[0]);
 299         let pack_arg = trans_operand(fx, &args[1]);
 300         let mut args = Vec::new();
 301         args.push(self_arg);
 302         match pack_arg.layout().ty.sty {
 303             ty::TyTuple(ref tupled_arguments) => {
 304                 for (i, _) in tupled_arguments.iter().enumerate() {
 305                     args.push(pack_arg.value_field(fx, mir::Field::new(i)));
 306                 }
 307             }
 308             _ => bug!("argument to function with \"rust-call\" ABI is not a tuple"),
 309         }
 310         println!(
 311             "{:?} {:?}",
 312             pack_arg.layout().ty,
 313             args.iter().map(|a| a.layout().ty).collect::<Vec<_>>()
 314         );
 315         args
 316     } else {
 317         args.into_iter()
 318             .map(|arg| trans_operand(fx, arg))
 319             .collect::<Vec<_>>()
 320     };
 321
 322     if let TypeVariants::TyFnDef(def_id, substs) = fn_ty.sty {
 323         if sig.abi == Abi::RustIntrinsic {
 324             let intrinsic = fx.tcx.item_name(def_id).as_str();
 325             let intrinsic = &intrinsic[..];
 326
 327             let nil_ty = fx.tcx.mk_nil();
 328             let u64_layout = fx.layout_of(fx.tcx.types.u64);
 329             let usize_layout = fx.layout_of(fx.tcx.types.usize);
 330
 331             let ret = match return_place {
 332                 Some(ret) => ret,
 333                 None => {
 334                     println!("codegen_call(fx, {:?}, {:?}, {:?})", func, args, destination);
 335                     // Insert non returning intrinsics here
 336                     match intrinsic {
 337                         "abort" => {
 338                             fx.bcx.ins().trap(TrapCode::User(!0 - 1));
 339                         }
 340                         "unreachable" => {
 341                             fx.bcx.ins().trap(TrapCode::User(!0 - 1));
 342                         }
 343                         _ => unimplemented!("unsupported instrinsic {}", intrinsic),
 344                     }
 345                     return;
 346                 }
 347             };
 348             match intrinsic {
 349                 "assume" => {
 350                     assert_eq!(args.len(), 1);
 351                 }
 352                 "likely" | "unlikely" => {
 353                     assert_eq!(args.len(), 1);
 354                     ret.write_cvalue(fx, args[0]);
 355                 }
 356                 "copy" | "copy_nonoverlapping" => {
 357                     let elem_ty = substs.type_at(0);
 358                     let elem_size: u64 = fx.layout_of(elem_ty).size.bytes();
 359                     let elem_size = fx.bcx.ins().iconst(types::I64, elem_size as i64);
 360                     assert_eq!(args.len(), 3);
 361                     let src = args[0];
 362                     let dst = args[1];
 363                     let count = args[2].load_value(fx);
 364                     let byte_amount = fx.bcx.ins().imul(count, elem_size);
 365                     fx.easy_call(
 366                         "memmove",
 367                         &[dst, src, CValue::ByVal(byte_amount, usize_layout)],
 368                         nil_ty,
 369                     );
 370                 }
 371                 "discriminant_value" => {
 372                     assert_eq!(args.len(), 1);
 373                     let discr = crate::base::trans_get_discriminant(fx, args[0], ret.layout());
 374                     ret.write_cvalue(fx, discr);
 375                 }
 376                 "size_of" => {
 377                     assert_eq!(args.len(), 0);
 378                     let size_of = fx.layout_of(substs.type_at(0)).size.bytes();
 379                     let size_of = CValue::const_val(fx, usize_layout.ty, size_of as i64);
 380                     ret.write_cvalue(fx, size_of);
 381                 }
 382                 "type_id" => {
 383                     assert_eq!(args.len(), 0);
 384                     let type_id = fx.tcx.type_id_hash(substs.type_at(0));
 385                     let type_id = CValue::const_val(fx, u64_layout.ty, type_id as i64);
 386                     ret.write_cvalue(fx, type_id);
 387                 }
 388                 "min_align_of" => {
 389                     assert_eq!(args.len(), 0);
 390                     let min_align = fx.layout_of(substs.type_at(0)).align.abi();
 391                     let min_align = CValue::const_val(fx, usize_layout.ty, min_align as i64);
 392                     ret.write_cvalue(fx, min_align);
 393                 }
 394                 _ if intrinsic.starts_with("unchecked_") => {
 395                     assert_eq!(args.len(), 2);
 396                     let bin_op = match intrinsic {
 397                         "unchecked_div" => BinOp::Div,
 398                         "unchecked_rem" => BinOp::Rem,
 399                         "unchecked_shl" => BinOp::Shl,
 400                         "unchecked_shr" => BinOp::Shr,
 401                         _ => unimplemented!("intrinsic {}", intrinsic),
 402                     };
 403                     let res = match ret.layout().ty.sty {
 404                         TypeVariants::TyUint(_) => crate::base::trans_int_binop(
 405                             fx,
 406                             bin_op,
 407                             args[0],
 408                             args[1],
 409                             ret.layout().ty,
 410                             false,
 411                         ),
 412                         TypeVariants::TyInt(_) => crate::base::trans_int_binop(
 413                             fx,
 414                             bin_op,
 415                             args[0],
 416                             args[1],
 417                             ret.layout().ty,
 418                             true,
 419                         ),
 420                         _ => panic!(),
 421                     };
 422                     ret.write_cvalue(fx, res);
 423                 }
 424                 _ if intrinsic.ends_with("_with_overflow") => {
 425                     assert_eq!(args.len(), 2);
 426                     assert_eq!(args[0].layout().ty, args[1].layout().ty);
 427                     let bin_op = match intrinsic {
 428                         "add_with_overflow" => BinOp::Add,
 429                         "sub_with_overflow" => BinOp::Sub,
 430                         "mul_with_overflow" => BinOp::Mul,
 431                         _ => unimplemented!("intrinsic {}", intrinsic),
 432                     };
 433                     let res = match args[0].layout().ty.sty {
 434                         TypeVariants::TyUint(_) => crate::base::trans_checked_int_binop(
 435                             fx,
 436                             bin_op,
 437                             args[0],
 438                             args[1],
 439                             ret.layout().ty,
 440                             false,
 441                         ),
 442                         TypeVariants::TyInt(_) => crate::base::trans_checked_int_binop(
 443                             fx,
 444                             bin_op,
 445                             args[0],
 446                             args[1],
 447                             ret.layout().ty,
 448                             true,
 449                         ),
 450                         _ => panic!(),
 451                     };
 452                     ret.write_cvalue(fx, res);
 453                 }
 454                 _ if intrinsic.starts_with("overflowing_") => {
 455                     assert_eq!(args.len(), 2);
 456                     assert_eq!(args[0].layout().ty, args[1].layout().ty);
 457                     let bin_op = match intrinsic {
 458                         "overflowing_add" => BinOp::Add,
 459                         "overflowing_sub" => BinOp::Sub,
 460                         "overflowing_mul" => BinOp::Mul,
 461                         _ => unimplemented!("intrinsic {}", intrinsic),
 462                     };
 463                     let res = match args[0].layout().ty.sty {
 464                         TypeVariants::TyUint(_) => crate::base::trans_int_binop(
 465                             fx,
 466                             bin_op,
 467                             args[0],
 468                             args[1],
 469                             ret.layout().ty,
 470                             false,
 471                         ),
 472                         TypeVariants::TyInt(_) => crate::base::trans_int_binop(
 473                             fx,
 474                             bin_op,
 475                             args[0],
 476                             args[1],
 477                             ret.layout().ty,
 478                             true,
 479                         ),
 480                         _ => panic!(),
 481                     };
 482                     ret.write_cvalue(fx, res);
 483                 }
 484                 "offset" => {
 485                     assert_eq!(args.len(), 2);
 486                     let base = args[0].load_value(fx);
 487                     let offset = args[1].load_value(fx);
 488                     let res = fx.bcx.ins().iadd(base, offset);
 489                     ret.write_cvalue(fx, CValue::ByVal(res, args[0].layout()));
 490                 }
 491                 "transmute" => {
 492                     assert_eq!(args.len(), 1);
 493                     let src_ty = substs.type_at(0);
 494                     let dst_ty = substs.type_at(1);
 495                     assert_eq!(args[0].layout().ty, src_ty);
 496                     let addr = args[0].force_stack(fx);
 497                     let dst_layout = fx.layout_of(dst_ty);
 498                     ret.write_cvalue(fx, CValue::ByRef(addr, dst_layout))
 499                 }
 500                 "uninit" => {
 501                     assert_eq!(args.len(), 0);
 502                     let ty = substs.type_at(0);
 503                     let layout = fx.layout_of(ty);
 504                     let stack_slot = fx.bcx.create_stack_slot(StackSlotData {
 505                         kind: StackSlotKind::ExplicitSlot,
 506                         size: layout.size.bytes() as u32,
 507                         offset: None,
 508                     });
 509
 510                     let uninit_place = CPlace::from_stack_slot(fx, stack_slot, ty);
 511                     let uninit_val = uninit_place.to_cvalue(fx);
 512                     ret.write_cvalue(fx, uninit_val);
 513                 }
 514                 "ctlz" | "ctlz_nonzero" => {
 515                     assert_eq!(args.len(), 1);
 516                     let arg = args[0].load_value(fx);
 517                     let res = CValue::ByVal(fx.bcx.ins().clz(arg), args[0].layout());
 518                     ret.write_cvalue(fx, res);
 519                 }
 520                 "cttz" | "cttz_nonzero" => {
 521                     assert_eq!(args.len(), 1);
 522                     let arg = args[0].load_value(fx);
 523                     let res = CValue::ByVal(fx.bcx.ins().clz(arg), args[0].layout());
 524                     ret.write_cvalue(fx, res);
 525                 }
 526                 "ctpop" => {
 527                     assert_eq!(args.len(), 1);
 528                     let arg = args[0].load_value(fx);
 529                     let res = CValue::ByVal(fx.bcx.ins().popcnt(arg), args[0].layout());
 530                     ret.write_cvalue(fx, res);
 531                 }
 532                 _ => unimpl!("unsupported intrinsic {}", intrinsic),
 533             }
 534             if let Some((_, dest)) = *destination {
 535                 let ret_ebb = fx.get_ebb(dest);
 536                 fx.bcx.ins().jump(ret_ebb, &[]);
 537             } else {
 538                 fx.bcx.ins().trap(TrapCode::User(!0));
 539             }
 540             return;
 541         }
 542     }
 543
 544     let return_ptr = match return_place {
 545         Some(place) => place.expect_addr(),
 546         None => fx.bcx.ins().iconst(types::I64, 0),
 547     };
 548
 549     let call_args = Some(return_ptr)
 550         .into_iter()
 551         .chain(args.into_iter().map(|arg| {
 552             if fx.cton_type(arg.layout().ty).is_some() {
 553                 arg.load_value(fx)
 554             } else {
 555                 arg.force_stack(fx)
 556             }
 557         })).collect::<Vec<_>>();
 558
 559     match func {
 560         CValue::Func(func, _) => {
 561             fx.bcx.ins().call(func, &call_args);
 562         }
 563         func => {
 564             let func_ty = func.layout().ty;
 565             let func = func.load_value(fx);
 566             let sig = fx
 567                 .bcx
 568                 .import_signature(cton_sig_from_fn_ty(fx.tcx, func_ty));
 569             fx.bcx.ins().call_indirect(sig, func, &call_args);
 570         }
 571     }
 572     if let Some((_, dest)) = *destination {
 573         let ret_ebb = fx.get_ebb(dest);
 574         fx.bcx.ins().jump(ret_ebb, &[]);
 575     } else {
 576         fx.bcx.ins().trap(TrapCode::User(!0));
 577     }
 578 }