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 #[derive(Debug)]
   9 enum PassMode {
  10     NoPass,
  11     ByVal(Type),
  12     ByRef,
  13 }
  14
  15 impl PassMode {
  16     fn get_param_ty(self, fx: &FunctionCx<impl Backend>) -> Type {
  17         match self {
  18             PassMode::NoPass => unimplemented!("pass mode nopass"),
  19             PassMode::ByVal(cton_type) => cton_type,
  20             PassMode::ByRef => fx.module.pointer_type(),
  21         }
  22     }
  23 }
  24
  25 fn get_pass_mode<'a, 'tcx: 'a>(
  26     tcx: TyCtxt<'a, 'tcx, 'tcx>,
  27     abi: Abi,
  28     ty: Ty<'tcx>,
  29     is_return: bool,
  30 ) -> PassMode {
  31     assert!(
  32         !tcx.layout_of(ParamEnv::reveal_all().and(ty))
  33             .unwrap()
  34             .is_unsized()
  35     );
  36     if ty.sty == tcx.mk_nil().sty {
  37         if is_return {
  38             //if false {
  39             PassMode::NoPass
  40         } else {
  41             PassMode::ByRef
  42         }
  43     } else if let Some(ret_ty) = crate::common::cton_type_from_ty(tcx, ty) {
  44         PassMode::ByVal(ret_ty)
  45     } else {
  46         if abi == Abi::C {
  47             unimplemented!("Non scalars are not yet supported for \"C\" abi");
  48         }
  49         PassMode::ByRef
  50     }
  51 }
  52
  53 pub fn cton_sig_from_fn_ty<'a, 'tcx: 'a>(
  54     tcx: TyCtxt<'a, 'tcx, 'tcx>,
  55     fn_ty: Ty<'tcx>,
  56 ) -> Signature {
  57     let sig = ty_fn_sig(tcx, fn_ty);
  58     assert!(!sig.variadic, "Variadic function are not yet supported");
  59     let (call_conv, inputs, output): (CallConv, Vec<Ty>, Ty) = match sig.abi {
  60         Abi::Rust => (CallConv::Fast, sig.inputs().to_vec(), sig.output()),
  61         Abi::C => (CallConv::SystemV, sig.inputs().to_vec(), sig.output()),
  62         Abi::RustCall => {
  63             assert_eq!(sig.inputs().len(), 2);
  64             let extra_args = match sig.inputs().last().unwrap().sty {
  65                 ty::Tuple(ref tupled_arguments) => tupled_arguments,
  66                 _ => bug!("argument to function with \"rust-call\" ABI is not a tuple"),
  67             };
  68             let mut inputs: Vec<Ty> = vec![sig.inputs()[0]];
  69             inputs.extend(extra_args.into_iter());
  70             (CallConv::Fast, inputs, sig.output())
  71         }
  72         Abi::System => bug!("system abi should be selected elsewhere"),
  73         Abi::RustIntrinsic => (CallConv::SystemV, sig.inputs().to_vec(), sig.output()),
  74         _ => unimplemented!("unsupported abi {:?}", sig.abi),
  75     };
  76
  77     let inputs = inputs
  78         .into_iter()
  79         .filter_map(|ty| match get_pass_mode(tcx, sig.abi, ty, false) {
  80             PassMode::ByVal(cton_ty) => Some(cton_ty),
  81             PassMode::NoPass => unimplemented!("pass mode nopass"),
  82             PassMode::ByRef => Some(pointer_ty(tcx)),
  83         });
  84
  85     let (params, returns) = match get_pass_mode(tcx, sig.abi, output, true) {
  86         PassMode::NoPass => (inputs.map(AbiParam::new).collect(), vec![]),
  87         PassMode::ByVal(ret_ty) => (
  88             inputs.map(AbiParam::new).collect(),
  89             vec![AbiParam::new(ret_ty)],
  90         ),
  91         PassMode::ByRef => {
  92             (
  93                 Some(pointer_ty(tcx)).into_iter() // First param is place to put return val
  94                     .chain(inputs)
  95                     .map(AbiParam::new)
  96                     .collect(),
  97                 vec![],
  98             )
  99         }
 100     };
 101
 102     Signature {
 103         params,
 104         returns,
 105         call_conv,
 106     }
 107 }
 108
 109 fn ty_fn_sig<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, ty: Ty<'tcx>) -> ty::FnSig<'tcx> {
 110     let sig = match ty.sty {
 111         ty::FnDef(..) |
 112         // Shims currently have type TyFnPtr. Not sure this should remain.
 113         ty::FnPtr(_) => ty.fn_sig(tcx),
 114         ty::Closure(def_id, substs) => {
 115             let sig = substs.closure_sig(def_id, tcx);
 116
 117             let env_ty = tcx.closure_env_ty(def_id, substs).unwrap();
 118             sig.map_bound(|sig| tcx.mk_fn_sig(
 119                 iter::once(*env_ty.skip_binder()).chain(sig.inputs().iter().cloned()),
 120                 sig.output(),
 121                 sig.variadic,
 122                 sig.unsafety,
 123                 sig.abi
 124             ))
 125         }
 126         ty::Generator(def_id, substs, _) => {
 127             let sig = substs.poly_sig(def_id, tcx);
 128
 129             let env_region = ty::ReLateBound(ty::INNERMOST, ty::BrEnv);
 130             let env_ty = tcx.mk_mut_ref(tcx.mk_region(env_region), ty);
 131
 132             sig.map_bound(|sig| {
 133                 let state_did = tcx.lang_items().gen_state().unwrap();
 134                 let state_adt_ref = tcx.adt_def(state_did);
 135                 let state_substs = tcx.intern_substs(&[
 136                     sig.yield_ty.into(),
 137                     sig.return_ty.into(),
 138                 ]);
 139                 let ret_ty = tcx.mk_adt(state_adt_ref, state_substs);
 140
 141                 tcx.mk_fn_sig(iter::once(env_ty),
 142                     ret_ty,
 143                     false,
 144                     hir::Unsafety::Normal,
 145                     Abi::Rust
 146                 )
 147             })
 148         }
 149         _ => bug!("unexpected type {:?} to ty_fn_sig", ty)
 150     };
 151     tcx.normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), &sig)
 152 }
 153
 154 pub fn get_function_name_and_sig<'a, 'tcx>(
 155     tcx: TyCtxt<'a, 'tcx, 'tcx>,
 156     inst: Instance<'tcx>,
 157 ) -> (String, Signature) {
 158     assert!(!inst.substs.needs_infer() && !inst.substs.has_param_types());
 159     let fn_ty = inst.ty(tcx);
 160     let sig = cton_sig_from_fn_ty(tcx, fn_ty);
 161     (tcx.symbol_name(inst).as_str().to_string(), sig)
 162 }
 163
 164 impl<'a, 'tcx: 'a, B: Backend + 'a> FunctionCx<'a, 'tcx, B> {
 165     /// Instance must be monomorphized
 166     pub fn get_function_ref(&mut self, inst: Instance<'tcx>) -> FuncRef {
 167         let (name, sig) = get_function_name_and_sig(self.tcx, inst);
 168         let func_id = self
 169             .module
 170             .declare_function(&name, Linkage::Import, &sig)
 171             .unwrap();
 172         self.module
 173             .declare_func_in_func(func_id, &mut self.bcx.func)
 174     }
 175
 176     fn lib_call(
 177         &mut self,
 178         name: &str,
 179         input_tys: Vec<types::Type>,
 180         output_ty: Option<types::Type>,
 181         args: &[Value],
 182     ) -> Option<Value> {
 183         let sig = Signature {
 184             params: input_tys.iter().cloned().map(AbiParam::new).collect(),
 185             returns: output_ty.map(|output_ty| vec![AbiParam::new(output_ty)]).unwrap_or(Vec::new()),
 186             call_conv: CallConv::SystemV,
 187         };
 188         let func_id = self
 189             .module
 190             .declare_function(&name, Linkage::Import, &sig)
 191             .unwrap();
 192         let func_ref = self
 193             .module
 194             .declare_func_in_func(func_id, &mut self.bcx.func);
 195         let call_inst = self.bcx.ins().call(func_ref, args);
 196         if output_ty.is_none() {
 197             return None;
 198         }
 199         let results = self.bcx.inst_results(call_inst);
 200         assert_eq!(results.len(), 1);
 201         Some(results[0])
 202     }
 203
 204     pub fn easy_call(
 205         &mut self,
 206         name: &str,
 207         args: &[CValue<'tcx>],
 208         return_ty: Ty<'tcx>,
 209     ) -> CValue<'tcx> {
 210         let (input_tys, args): (Vec<_>, Vec<_>) = args
 211             .into_iter()
 212             .map(|arg| {
 213                 (
 214                     self.cton_type(arg.layout().ty).unwrap(),
 215                     arg.load_value(self),
 216                 )
 217             }).unzip();
 218         let return_layout = self.layout_of(return_ty);
 219         let return_ty = if let ty::Tuple(tup) = return_ty.sty {
 220             if !tup.is_empty() {
 221                 bug!("easy_call( (...) -> <non empty tuple> ) is not allowed");
 222             }
 223             None
 224         } else {
 225             Some(self.cton_type(return_ty).unwrap())
 226         };
 227         if let Some(val) = self.lib_call(name, input_tys, return_ty, &args) {
 228             CValue::ByVal(val, return_layout)
 229         } else {
 230             CValue::ByRef(
 231                 self.bcx.ins().iconst(self.module.pointer_type(), 0),
 232                 return_layout,
 233             )
 234         }
 235     }
 236
 237     fn self_sig(&self) -> FnSig<'tcx> {
 238         ty_fn_sig(self.tcx, self.instance.ty(self.tcx))
 239     }
 240
 241     fn return_type(&self) -> Ty<'tcx> {
 242         self.self_sig().output()
 243     }
 244 }
 245
 246 pub fn codegen_fn_prelude<'a, 'tcx: 'a>(
 247     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 248     start_ebb: Ebb,
 249 ) {
 250     let ssa_analyzed = crate::analyze::analyze(fx);
 251
 252     let ret_layout = fx.layout_of(fx.return_type());
 253     let output_pass_mode = get_pass_mode(fx.tcx, fx.self_sig().abi, fx.return_type(), true);
 254     let ret_param = match output_pass_mode {
 255         PassMode::NoPass => None,
 256         PassMode::ByVal(_) => None,
 257         PassMode::ByRef => Some(fx.bcx.append_ebb_param(start_ebb, fx.module.pointer_type())),
 258     };
 259
 260     enum ArgKind {
 261         Normal(Value),
 262         Spread(Vec<Value>),
 263     }
 264
 265     let func_params = fx
 266         .mir
 267         .args_iter()
 268         .map(|local| {
 269             let arg_ty = fx.monomorphize(&fx.mir.local_decls[local].ty);
 270
 271             // Adapted from https://github.com/rust-lang/rust/blob/145155dc96757002c7b2e9de8489416e2fdbbd57/src/librustc_codegen_llvm/mir/mod.rs#L442-L482
 272             if Some(local) == fx.mir.spread_arg {
 273                 // This argument (e.g. the last argument in the "rust-call" ABI)
 274                 // is a tuple that was spread at the ABI level and now we have
 275                 // to reconstruct it into a tuple local variable, from multiple
 276                 // individual function arguments.
 277
 278                 let tupled_arg_tys = match arg_ty.sty {
 279                     ty::Tuple(ref tys) => tys,
 280                     _ => bug!("spread argument isn't a tuple?! but {:?}", arg_ty),
 281                 };
 282
 283                 let mut ebb_params = Vec::new();
 284                 for arg_ty in tupled_arg_tys.iter() {
 285                     let cton_type =
 286                         get_pass_mode(fx.tcx, fx.self_sig().abi, arg_ty, false).get_param_ty(fx);
 287                     ebb_params.push(fx.bcx.append_ebb_param(start_ebb, cton_type));
 288                 }
 289
 290                 (local, ArgKind::Spread(ebb_params), arg_ty)
 291             } else {
 292                 let cton_type =
 293                     get_pass_mode(fx.tcx, fx.self_sig().abi, arg_ty, false).get_param_ty(fx);
 294                 (
 295                     local,
 296                     ArgKind::Normal(fx.bcx.append_ebb_param(start_ebb, cton_type)),
 297                     arg_ty,
 298                 )
 299             }
 300         }).collect::<Vec<(Local, ArgKind, Ty)>>();
 301
 302     fx.bcx.switch_to_block(start_ebb);
 303
 304     fx.top_nop = Some(fx.bcx.ins().nop());
 305     fx.add_global_comment(format!("ssa {:?}", ssa_analyzed));
 306
 307     match output_pass_mode {
 308         PassMode::NoPass => {
 309             let null = fx.bcx.ins().iconst(fx.module.pointer_type(), 0);
 310             //unimplemented!("pass mode nopass");
 311             fx.local_map.insert(
 312                 RETURN_PLACE,
 313                 CPlace::Addr(null, None, fx.layout_of(fx.return_type())),
 314             );
 315         }
 316         PassMode::ByVal(ret_ty) => {
 317             fx.bcx.declare_var(mir_var(RETURN_PLACE), ret_ty);
 318             fx.local_map
 319                 .insert(RETURN_PLACE, CPlace::Var(RETURN_PLACE, ret_layout));
 320         }
 321         PassMode::ByRef => {
 322             fx.local_map.insert(
 323                 RETURN_PLACE,
 324                 CPlace::Addr(ret_param.unwrap(), None, ret_layout),
 325             );
 326         }
 327     }
 328
 329     for (local, arg_kind, ty) in func_params {
 330         let layout = fx.layout_of(ty);
 331
 332         if let ArgKind::Normal(ebb_param) = arg_kind {
 333             if !ssa_analyzed
 334                 .get(&local)
 335                 .unwrap()
 336                 .contains(crate::analyze::Flags::NOT_SSA)
 337             {
 338                 fx.bcx
 339                     .declare_var(mir_var(local), fx.cton_type(ty).unwrap());
 340                 match get_pass_mode(fx.tcx, fx.self_sig().abi, ty, false) {
 341                     PassMode::NoPass => unimplemented!("pass mode nopass"),
 342                     PassMode::ByVal(_) => fx.bcx.def_var(mir_var(local), ebb_param),
 343                     PassMode::ByRef => {
 344                         let val = CValue::ByRef(ebb_param, fx.layout_of(ty)).load_value(fx);
 345                         fx.bcx.def_var(mir_var(local), val);
 346                     }
 347                 }
 348                 fx.local_map.insert(local, CPlace::Var(local, layout));
 349                 continue;
 350             }
 351         }
 352
 353         let stack_slot = fx.bcx.create_stack_slot(StackSlotData {
 354             kind: StackSlotKind::ExplicitSlot,
 355             size: layout.size.bytes() as u32,
 356             offset: None,
 357         });
 358
 359         let place = CPlace::from_stack_slot(fx, stack_slot, ty);
 360
 361         match arg_kind {
 362             ArgKind::Normal(ebb_param) => match get_pass_mode(fx.tcx, fx.self_sig().abi, ty, false)
 363             {
 364                 PassMode::NoPass => unimplemented!("pass mode nopass"),
 365                 PassMode::ByVal(_) => {
 366                     place.write_cvalue(fx, CValue::ByVal(ebb_param, place.layout()))
 367                 }
 368                 PassMode::ByRef => place.write_cvalue(fx, CValue::ByRef(ebb_param, place.layout())),
 369             },
 370             ArgKind::Spread(ebb_params) => {
 371                 for (i, ebb_param) in ebb_params.into_iter().enumerate() {
 372                     let sub_place = place.place_field(fx, mir::Field::new(i));
 373                     match get_pass_mode(fx.tcx, fx.self_sig().abi, sub_place.layout().ty, false) {
 374                         PassMode::NoPass => unimplemented!("pass mode nopass"),
 375                         PassMode::ByVal(_) => {
 376                             sub_place.write_cvalue(fx, CValue::ByVal(ebb_param, sub_place.layout()))
 377                         }
 378                         PassMode::ByRef => {
 379                             sub_place.write_cvalue(fx, CValue::ByRef(ebb_param, sub_place.layout()))
 380                         }
 381                     }
 382                 }
 383             }
 384         }
 385         fx.local_map.insert(local, place);
 386     }
 387
 388     for local in fx.mir.vars_and_temps_iter() {
 389         let ty = fx.mir.local_decls[local].ty;
 390         let layout = fx.layout_of(ty);
 391
 392         let place = if ssa_analyzed
 393             .get(&local)
 394             .unwrap()
 395             .contains(crate::analyze::Flags::NOT_SSA)
 396         {
 397             let stack_slot = fx.bcx.create_stack_slot(StackSlotData {
 398                 kind: StackSlotKind::ExplicitSlot,
 399                 size: layout.size.bytes() as u32,
 400                 offset: None,
 401             });
 402             CPlace::from_stack_slot(fx, stack_slot, ty)
 403         } else {
 404             fx.bcx
 405                 .declare_var(mir_var(local), fx.cton_type(ty).unwrap());
 406             CPlace::Var(local, layout)
 407         };
 408
 409         fx.local_map.insert(local, place);
 410     }
 411
 412     fx.bcx
 413         .ins()
 414         .jump(*fx.ebb_map.get(&START_BLOCK).unwrap(), &[]);
 415 }
 416
 417 pub fn codegen_call<'a, 'tcx: 'a>(
 418     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 419     func: &Operand<'tcx>,
 420     args: &[Operand<'tcx>],
 421     destination: &Option<(Place<'tcx>, BasicBlock)>,
 422 ) {
 423     let fn_ty = fx.monomorphize(&func.ty(&fx.mir.local_decls, fx.tcx));
 424     let sig = ty_fn_sig(fx.tcx, fn_ty);
 425
 426     // Unpack arguments tuple for closures
 427     let args = if sig.abi == Abi::RustCall {
 428         assert_eq!(args.len(), 2, "rust-call abi requires two arguments");
 429         let self_arg = trans_operand(fx, &args[0]);
 430         let pack_arg = trans_operand(fx, &args[1]);
 431         let mut args = Vec::new();
 432         args.push(self_arg);
 433         match pack_arg.layout().ty.sty {
 434             ty::Tuple(ref tupled_arguments) => {
 435                 for (i, _) in tupled_arguments.iter().enumerate() {
 436                     args.push(pack_arg.value_field(fx, mir::Field::new(i)));
 437                 }
 438             }
 439             _ => bug!("argument to function with \"rust-call\" ABI is not a tuple"),
 440         }
 441         args
 442     } else {
 443         args.into_iter()
 444             .map(|arg| trans_operand(fx, arg))
 445             .collect::<Vec<_>>()
 446     };
 447
 448     let destination = destination
 449         .as_ref()
 450         .map(|(place, bb)| (trans_place(fx, place), *bb));
 451
 452     if codegen_intrinsic_call(fx, fn_ty, sig, &args, destination) {
 453         return;
 454     }
 455
 456     let ret_layout = fx.layout_of(sig.output());
 457
 458     let output_pass_mode = get_pass_mode(fx.tcx, sig.abi, sig.output(), true);
 459     let return_ptr = match output_pass_mode {
 460         PassMode::NoPass => None,
 461         PassMode::ByRef => match destination {
 462             Some((place, _)) => Some(place.expect_addr()),
 463             None => Some(fx.bcx.ins().iconst(fx.module.pointer_type(), 0)),
 464         },
 465         PassMode::ByVal(_) => None,
 466     };
 467
 468     let call_args: Vec<Value> = return_ptr
 469         .into_iter()
 470         .chain(args.into_iter().map(|arg| {
 471             match get_pass_mode(fx.tcx, sig.abi, arg.layout().ty, false) {
 472                 PassMode::NoPass => unimplemented!("pass mode nopass"),
 473                 PassMode::ByVal(_) => arg.load_value(fx),
 474                 PassMode::ByRef => arg.force_stack(fx),
 475             }
 476         })).collect::<Vec<_>>();
 477
 478     let call_inst = match fn_ty.sty {
 479         ty::FnDef(def_id, substs) => {
 480             let inst = Instance::resolve(fx.tcx, ParamEnv::reveal_all(), def_id, substs).unwrap();
 481             let func_ref = fx.get_function_ref(inst);
 482             fx.bcx.ins().call(func_ref, &call_args)
 483         }
 484         ty::FnPtr(_) => {
 485             let func = trans_operand(fx, func);
 486             let func = func.load_value(fx);
 487             let sig = fx.bcx.import_signature(cton_sig_from_fn_ty(fx.tcx, fn_ty));
 488             fx.bcx.ins().call_indirect(sig, func, &call_args)
 489         }
 490         _ => bug!("{:?}", fn_ty),
 491     };
 492
 493     match output_pass_mode {
 494         PassMode::NoPass => {}
 495         PassMode::ByVal(_) => {
 496             if let Some((ret_place, _)) = destination {
 497                 let results = fx.bcx.inst_results(call_inst);
 498                 ret_place.write_cvalue(fx, CValue::ByVal(results[0], ret_layout));
 499             }
 500         }
 501         PassMode::ByRef => {}
 502     }
 503     if let Some((_, dest)) = destination {
 504         let ret_ebb = fx.get_ebb(dest);
 505         fx.bcx.ins().jump(ret_ebb, &[]);
 506     } else {
 507         fx.bcx.ins().trap(TrapCode::User(!0));
 508     }
 509 }
 510
 511 pub fn codegen_return(fx: &mut FunctionCx<impl Backend>) {
 512     match get_pass_mode(fx.tcx, fx.self_sig().abi, fx.return_type(), true) {
 513         PassMode::NoPass | PassMode::ByRef => {
 514             fx.bcx.ins().return_(&[]);
 515         }
 516         PassMode::ByVal(_) => {
 517             let place = fx.get_local_place(RETURN_PLACE);
 518             let ret_val = place.to_cvalue(fx).load_value(fx);
 519             fx.bcx.ins().return_(&[ret_val]);
 520         }
 521     }
 522 }
 523
 524 fn codegen_intrinsic_call<'a, 'tcx: 'a>(
 525     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 526     fn_ty: Ty<'tcx>,
 527     sig: FnSig<'tcx>,
 528     args: &[CValue<'tcx>],
 529     destination: Option<(CPlace<'tcx>, BasicBlock)>,
 530 ) -> bool {
 531     if let ty::FnDef(def_id, substs) = fn_ty.sty {
 532         if sig.abi == Abi::RustIntrinsic {
 533             let intrinsic = fx.tcx.item_name(def_id).as_str();
 534             let intrinsic = &intrinsic[..];
 535
 536             let ret = match destination {
 537                 Some((place, _)) => place,
 538                 None => {
 539                     // Insert non returning intrinsics here
 540                     match intrinsic {
 541                         "abort" => {
 542                             fx.bcx.ins().trap(TrapCode::User(!0 - 1));
 543                         }
 544                         "unreachable" => {
 545                             fx.bcx.ins().trap(TrapCode::User(!0 - 1));
 546                         }
 547                         _ => unimplemented!("unsupported instrinsic {}", intrinsic),
 548                     }
 549                     return true;
 550                 }
 551             };
 552
 553             let nil_ty = fx.tcx.mk_nil();
 554             let u64_layout = fx.layout_of(fx.tcx.types.u64);
 555             let usize_layout = fx.layout_of(fx.tcx.types.usize);
 556
 557             match intrinsic {
 558                 "assume" => {
 559                     assert_eq!(args.len(), 1);
 560                 }
 561                 "arith_offset" => {
 562                     assert_eq!(args.len(), 2);
 563                     let base = args[0].load_value(fx);
 564                     let offset = args[1].load_value(fx);
 565                     let res = fx.bcx.ins().iadd(base, offset);
 566                     let res = CValue::ByVal(res, ret.layout());
 567                     ret.write_cvalue(fx, res);
 568                 }
 569                 "likely" | "unlikely" => {
 570                     assert_eq!(args.len(), 1);
 571                     ret.write_cvalue(fx, args[0]);
 572                 }
 573                 "copy" | "copy_nonoverlapping" => {
 574                     let elem_ty = substs.type_at(0);
 575                     let elem_size: u64 = fx.layout_of(elem_ty).size.bytes();
 576                     let elem_size = fx
 577                         .bcx
 578                         .ins()
 579                         .iconst(fx.module.pointer_type(), elem_size as i64);
 580                     assert_eq!(args.len(), 3);
 581                     let src = args[0];
 582                     let dst = args[1];
 583                     let count = args[2].load_value(fx);
 584                     let byte_amount = fx.bcx.ins().imul(count, elem_size);
 585                     fx.easy_call(
 586                         "memmove",
 587                         &[dst, src, CValue::ByVal(byte_amount, usize_layout)],
 588                         nil_ty,
 589                     );
 590                 }
 591                 "discriminant_value" => {
 592                     assert_eq!(args.len(), 1);
 593                     let discr = crate::base::trans_get_discriminant(fx, args[0], ret.layout());
 594                     ret.write_cvalue(fx, discr);
 595                 }
 596                 "size_of" => {
 597                     assert_eq!(args.len(), 0);
 598                     let size_of = fx.layout_of(substs.type_at(0)).size.bytes();
 599                     let size_of = CValue::const_val(fx, usize_layout.ty, size_of as i64);
 600                     ret.write_cvalue(fx, size_of);
 601                 }
 602                 "size_of_val" => {
 603                     assert_eq!(args.len(), 1);
 604                     let size = match &substs.type_at(0).sty {
 605                         ty::Slice(elem) => {
 606                             let len = args[0].load_value_pair(fx).1;
 607                             let elem_size = fx.layout_of(elem).size.bytes();
 608                             fx.bcx.ins().imul_imm(len, elem_size as i64)
 609                         },
 610                         ty => unimplemented!("size_of_val for {:?}", ty),
 611                     };
 612                     ret.write_cvalue(fx, CValue::ByVal(size, usize_layout));
 613                 }
 614                 "type_id" => {
 615                     assert_eq!(args.len(), 0);
 616                     let type_id = fx.tcx.type_id_hash(substs.type_at(0));
 617                     let type_id = CValue::const_val(fx, u64_layout.ty, type_id as i64);
 618                     ret.write_cvalue(fx, type_id);
 619                 }
 620                 "min_align_of" => {
 621                     assert_eq!(args.len(), 0);
 622                     let min_align = fx.layout_of(substs.type_at(0)).align.abi();
 623                     let min_align = CValue::const_val(fx, usize_layout.ty, min_align as i64);
 624                     ret.write_cvalue(fx, min_align);
 625                 }
 626                 _ if intrinsic.starts_with("unchecked_") => {
 627                     assert_eq!(args.len(), 2);
 628                     let bin_op = match intrinsic {
 629                         "unchecked_div" => BinOp::Div,
 630                         "unchecked_rem" => BinOp::Rem,
 631                         "unchecked_shl" => BinOp::Shl,
 632                         "unchecked_shr" => BinOp::Shr,
 633                         _ => unimplemented!("intrinsic {}", intrinsic),
 634                     };
 635                     let res = match ret.layout().ty.sty {
 636                         ty::Uint(_) => crate::base::trans_int_binop(
 637                             fx,
 638                             bin_op,
 639                             args[0],
 640                             args[1],
 641                             ret.layout().ty,
 642                             false,
 643                         ),
 644                         ty::Int(_) => crate::base::trans_int_binop(
 645                             fx,
 646                             bin_op,
 647                             args[0],
 648                             args[1],
 649                             ret.layout().ty,
 650                             true,
 651                         ),
 652                         _ => panic!(),
 653                     };
 654                     ret.write_cvalue(fx, res);
 655                 }
 656                 _ if intrinsic.ends_with("_with_overflow") => {
 657                     assert_eq!(args.len(), 2);
 658                     assert_eq!(args[0].layout().ty, args[1].layout().ty);
 659                     let bin_op = match intrinsic {
 660                         "add_with_overflow" => BinOp::Add,
 661                         "sub_with_overflow" => BinOp::Sub,
 662                         "mul_with_overflow" => BinOp::Mul,
 663                         _ => unimplemented!("intrinsic {}", intrinsic),
 664                     };
 665                     let res = match args[0].layout().ty.sty {
 666                         ty::Uint(_) => crate::base::trans_checked_int_binop(
 667                             fx,
 668                             bin_op,
 669                             args[0],
 670                             args[1],
 671                             ret.layout().ty,
 672                             false,
 673                         ),
 674                         ty::Int(_) => crate::base::trans_checked_int_binop(
 675                             fx,
 676                             bin_op,
 677                             args[0],
 678                             args[1],
 679                             ret.layout().ty,
 680                             true,
 681                         ),
 682                         _ => panic!(),
 683                     };
 684                     ret.write_cvalue(fx, res);
 685                 }
 686                 _ if intrinsic.starts_with("overflowing_") => {
 687                     assert_eq!(args.len(), 2);
 688                     assert_eq!(args[0].layout().ty, args[1].layout().ty);
 689                     let bin_op = match intrinsic {
 690                         "overflowing_add" => BinOp::Add,
 691                         "overflowing_sub" => BinOp::Sub,
 692                         "overflowing_mul" => BinOp::Mul,
 693                         _ => unimplemented!("intrinsic {}", intrinsic),
 694                     };
 695                     let res = match args[0].layout().ty.sty {
 696                         ty::Uint(_) => crate::base::trans_int_binop(
 697                             fx,
 698                             bin_op,
 699                             args[0],
 700                             args[1],
 701                             ret.layout().ty,
 702                             false,
 703                         ),
 704                         ty::Int(_) => crate::base::trans_int_binop(
 705                             fx,
 706                             bin_op,
 707                             args[0],
 708                             args[1],
 709                             ret.layout().ty,
 710                             true,
 711                         ),
 712                         _ => panic!(),
 713                     };
 714                     ret.write_cvalue(fx, res);
 715                 }
 716                 "offset" => {
 717                     assert_eq!(args.len(), 2);
 718                     let base = args[0].load_value(fx);
 719                     let offset = args[1].load_value(fx);
 720                     let res = fx.bcx.ins().iadd(base, offset);
 721                     ret.write_cvalue(fx, CValue::ByVal(res, args[0].layout()));
 722                 }
 723                 "transmute" => {
 724                     assert_eq!(args.len(), 1);
 725                     let src_ty = substs.type_at(0);
 726                     let dst_ty = substs.type_at(1);
 727                     assert_eq!(args[0].layout().ty, src_ty);
 728                     let addr = args[0].force_stack(fx);
 729                     let dst_layout = fx.layout_of(dst_ty);
 730                     ret.write_cvalue(fx, CValue::ByRef(addr, dst_layout))
 731                 }
 732                 "uninit" => {
 733                     assert_eq!(args.len(), 0);
 734                     let ty = substs.type_at(0);
 735                     let layout = fx.layout_of(ty);
 736                     let stack_slot = fx.bcx.create_stack_slot(StackSlotData {
 737                         kind: StackSlotKind::ExplicitSlot,
 738                         size: layout.size.bytes() as u32,
 739                         offset: None,
 740                     });
 741
 742                     let uninit_place = CPlace::from_stack_slot(fx, stack_slot, ty);
 743                     let uninit_val = uninit_place.to_cvalue(fx);
 744                     ret.write_cvalue(fx, uninit_val);
 745                 }
 746                 "ctlz" | "ctlz_nonzero" => {
 747                     assert_eq!(args.len(), 1);
 748                     let arg = args[0].load_value(fx);
 749                     let res = CValue::ByVal(fx.bcx.ins().clz(arg), args[0].layout());
 750                     ret.write_cvalue(fx, res);
 751                 }
 752                 "cttz" | "cttz_nonzero" => {
 753                     assert_eq!(args.len(), 1);
 754                     let arg = args[0].load_value(fx);
 755                     let res = CValue::ByVal(fx.bcx.ins().clz(arg), args[0].layout());
 756                     ret.write_cvalue(fx, res);
 757                 }
 758                 "ctpop" => {
 759                     assert_eq!(args.len(), 1);
 760                     let arg = args[0].load_value(fx);
 761                     let res = CValue::ByVal(fx.bcx.ins().popcnt(arg), args[0].layout());
 762                     ret.write_cvalue(fx, res);
 763                 }
 764                 _ => unimpl!("unsupported intrinsic {}", intrinsic),
 765             }
 766
 767             if let Some((_, dest)) = destination {
 768                 let ret_ebb = fx.get_ebb(dest);
 769                 fx.bcx.ins().jump(ret_ebb, &[]);
 770             } else {
 771                 fx.bcx.ins().trap(TrapCode::User(!0));
 772             }
 773             return true;
 774         }
 775     }
 776
 777     false
 778 }