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     match fx.self_sig().abi {
 253         Abi::Rust | Abi::RustCall => {}
 254         _ => unimplemented!("declared function with non \"rust\" or \"rust-call\" abi"),
 255     }
 256
 257     let ret_layout = fx.layout_of(fx.return_type());
 258     let output_pass_mode = get_pass_mode(fx.tcx, fx.self_sig().abi, fx.return_type(), true);
 259     let ret_param = match output_pass_mode {
 260         PassMode::NoPass => None,
 261         PassMode::ByVal(_) => None,
 262         PassMode::ByRef => Some(fx.bcx.append_ebb_param(start_ebb, fx.module.pointer_type())),
 263     };
 264
 265     enum ArgKind {
 266         Normal(Value),
 267         Spread(Vec<Value>),
 268     }
 269
 270     let func_params = fx
 271         .mir
 272         .args_iter()
 273         .map(|local| {
 274             let arg_ty = fx.monomorphize(&fx.mir.local_decls[local].ty);
 275
 276             // Adapted from https://github.com/rust-lang/rust/blob/145155dc96757002c7b2e9de8489416e2fdbbd57/src/librustc_codegen_llvm/mir/mod.rs#L442-L482
 277             if Some(local) == fx.mir.spread_arg {
 278                 // This argument (e.g. the last argument in the "rust-call" ABI)
 279                 // is a tuple that was spread at the ABI level and now we have
 280                 // to reconstruct it into a tuple local variable, from multiple
 281                 // individual function arguments.
 282
 283                 let tupled_arg_tys = match arg_ty.sty {
 284                     ty::Tuple(ref tys) => tys,
 285                     _ => bug!("spread argument isn't a tuple?! but {:?}", arg_ty),
 286                 };
 287
 288                 let mut ebb_params = Vec::new();
 289                 for arg_ty in tupled_arg_tys.iter() {
 290                     let cton_type =
 291                         get_pass_mode(fx.tcx, fx.self_sig().abi, arg_ty, false).get_param_ty(fx);
 292                     ebb_params.push(fx.bcx.append_ebb_param(start_ebb, cton_type));
 293                 }
 294
 295                 (local, ArgKind::Spread(ebb_params), arg_ty)
 296             } else {
 297                 let cton_type =
 298                     get_pass_mode(fx.tcx, fx.self_sig().abi, arg_ty, false).get_param_ty(fx);
 299                 (
 300                     local,
 301                     ArgKind::Normal(fx.bcx.append_ebb_param(start_ebb, cton_type)),
 302                     arg_ty,
 303                 )
 304             }
 305         }).collect::<Vec<(Local, ArgKind, Ty)>>();
 306
 307     fx.bcx.switch_to_block(start_ebb);
 308
 309     fx.top_nop = Some(fx.bcx.ins().nop());
 310     fx.add_global_comment(format!("ssa {:?}", ssa_analyzed));
 311
 312     match output_pass_mode {
 313         PassMode::NoPass => {
 314             let null = fx.bcx.ins().iconst(fx.module.pointer_type(), 0);
 315             //unimplemented!("pass mode nopass");
 316             fx.local_map.insert(
 317                 RETURN_PLACE,
 318                 CPlace::Addr(null, None, fx.layout_of(fx.return_type())),
 319             );
 320         }
 321         PassMode::ByVal(ret_ty) => {
 322             fx.bcx.declare_var(mir_var(RETURN_PLACE), ret_ty);
 323             fx.local_map
 324                 .insert(RETURN_PLACE, CPlace::Var(RETURN_PLACE, ret_layout));
 325         }
 326         PassMode::ByRef => {
 327             fx.local_map.insert(
 328                 RETURN_PLACE,
 329                 CPlace::Addr(ret_param.unwrap(), None, ret_layout),
 330             );
 331         }
 332     }
 333
 334     for (local, arg_kind, ty) in func_params {
 335         let layout = fx.layout_of(ty);
 336
 337         if let ArgKind::Normal(ebb_param) = arg_kind {
 338             if !ssa_analyzed
 339                 .get(&local)
 340                 .unwrap()
 341                 .contains(crate::analyze::Flags::NOT_SSA)
 342             {
 343                 fx.bcx
 344                     .declare_var(mir_var(local), fx.cton_type(ty).unwrap());
 345                 match get_pass_mode(fx.tcx, fx.self_sig().abi, ty, false) {
 346                     PassMode::NoPass => unimplemented!("pass mode nopass"),
 347                     PassMode::ByVal(_) => fx.bcx.def_var(mir_var(local), ebb_param),
 348                     PassMode::ByRef => {
 349                         let val = CValue::ByRef(ebb_param, fx.layout_of(ty)).load_value(fx);
 350                         fx.bcx.def_var(mir_var(local), val);
 351                     }
 352                 }
 353                 fx.local_map.insert(local, CPlace::Var(local, layout));
 354                 continue;
 355             }
 356         }
 357
 358         let stack_slot = fx.bcx.create_stack_slot(StackSlotData {
 359             kind: StackSlotKind::ExplicitSlot,
 360             size: layout.size.bytes() as u32,
 361             offset: None,
 362         });
 363
 364         let place = CPlace::from_stack_slot(fx, stack_slot, ty);
 365
 366         match arg_kind {
 367             ArgKind::Normal(ebb_param) => match get_pass_mode(fx.tcx, fx.self_sig().abi, ty, false)
 368             {
 369                 PassMode::NoPass => unimplemented!("pass mode nopass"),
 370                 PassMode::ByVal(_) => {
 371                     place.write_cvalue(fx, CValue::ByVal(ebb_param, place.layout()))
 372                 }
 373                 PassMode::ByRef => place.write_cvalue(fx, CValue::ByRef(ebb_param, place.layout())),
 374             },
 375             ArgKind::Spread(ebb_params) => {
 376                 for (i, ebb_param) in ebb_params.into_iter().enumerate() {
 377                     let sub_place = place.place_field(fx, mir::Field::new(i));
 378                     match get_pass_mode(fx.tcx, fx.self_sig().abi, sub_place.layout().ty, false) {
 379                         PassMode::NoPass => unimplemented!("pass mode nopass"),
 380                         PassMode::ByVal(_) => {
 381                             sub_place.write_cvalue(fx, CValue::ByVal(ebb_param, sub_place.layout()))
 382                         }
 383                         PassMode::ByRef => {
 384                             sub_place.write_cvalue(fx, CValue::ByRef(ebb_param, sub_place.layout()))
 385                         }
 386                     }
 387                 }
 388             }
 389         }
 390         fx.local_map.insert(local, place);
 391     }
 392
 393     for local in fx.mir.vars_and_temps_iter() {
 394         let ty = fx.mir.local_decls[local].ty;
 395         let layout = fx.layout_of(ty);
 396
 397         let place = if ssa_analyzed
 398             .get(&local)
 399             .unwrap()
 400             .contains(crate::analyze::Flags::NOT_SSA)
 401         {
 402             let stack_slot = fx.bcx.create_stack_slot(StackSlotData {
 403                 kind: StackSlotKind::ExplicitSlot,
 404                 size: layout.size.bytes() as u32,
 405                 offset: None,
 406             });
 407             CPlace::from_stack_slot(fx, stack_slot, ty)
 408         } else {
 409             fx.bcx
 410                 .declare_var(mir_var(local), fx.cton_type(ty).unwrap());
 411             CPlace::Var(local, layout)
 412         };
 413
 414         fx.local_map.insert(local, place);
 415     }
 416
 417     fx.bcx
 418         .ins()
 419         .jump(*fx.ebb_map.get(&START_BLOCK).unwrap(), &[]);
 420 }
 421
 422 pub fn codegen_call<'a, 'tcx: 'a>(
 423     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 424     func: &Operand<'tcx>,
 425     args: &[Operand<'tcx>],
 426     destination: &Option<(Place<'tcx>, BasicBlock)>,
 427 ) {
 428     let fn_ty = fx.monomorphize(&func.ty(&fx.mir.local_decls, fx.tcx));
 429     let sig = ty_fn_sig(fx.tcx, fn_ty);
 430
 431     // Unpack arguments tuple for closures
 432     let args = if sig.abi == Abi::RustCall {
 433         assert_eq!(args.len(), 2, "rust-call abi requires two arguments");
 434         let self_arg = trans_operand(fx, &args[0]);
 435         let pack_arg = trans_operand(fx, &args[1]);
 436         let mut args = Vec::new();
 437         args.push(self_arg);
 438         match pack_arg.layout().ty.sty {
 439             ty::Tuple(ref tupled_arguments) => {
 440                 for (i, _) in tupled_arguments.iter().enumerate() {
 441                     args.push(pack_arg.value_field(fx, mir::Field::new(i)));
 442                 }
 443             }
 444             _ => bug!("argument to function with \"rust-call\" ABI is not a tuple"),
 445         }
 446         args
 447     } else {
 448         args.into_iter()
 449             .map(|arg| trans_operand(fx, arg))
 450             .collect::<Vec<_>>()
 451     };
 452
 453     let destination = destination
 454         .as_ref()
 455         .map(|(place, bb)| (trans_place(fx, place), *bb));
 456
 457     if codegen_intrinsic_call(fx, fn_ty, sig, &args, destination) {
 458         return;
 459     }
 460
 461     let ret_layout = fx.layout_of(sig.output());
 462
 463     let output_pass_mode = get_pass_mode(fx.tcx, sig.abi, sig.output(), true);
 464     let return_ptr = match output_pass_mode {
 465         PassMode::NoPass => None,
 466         PassMode::ByRef => match destination {
 467             Some((place, _)) => Some(place.expect_addr()),
 468             None => Some(fx.bcx.ins().iconst(fx.module.pointer_type(), 0)),
 469         },
 470         PassMode::ByVal(_) => None,
 471     };
 472
 473     let call_args: Vec<Value> = return_ptr
 474         .into_iter()
 475         .chain(args.into_iter().map(|arg| {
 476             match get_pass_mode(fx.tcx, sig.abi, arg.layout().ty, false) {
 477                 PassMode::NoPass => unimplemented!("pass mode nopass"),
 478                 PassMode::ByVal(_) => arg.load_value(fx),
 479                 PassMode::ByRef => arg.force_stack(fx),
 480             }
 481         })).collect::<Vec<_>>();
 482
 483     let call_inst = match fn_ty.sty {
 484         ty::FnDef(def_id, substs) => {
 485             let inst = Instance::resolve(fx.tcx, ParamEnv::reveal_all(), def_id, substs).unwrap();
 486             let func_ref = fx.get_function_ref(inst);
 487             fx.bcx.ins().call(func_ref, &call_args)
 488         }
 489         ty::FnPtr(_) => {
 490             let func = trans_operand(fx, func);
 491             let func = func.load_value(fx);
 492             let sig = fx.bcx.import_signature(cton_sig_from_fn_ty(fx.tcx, fn_ty));
 493             fx.bcx.ins().call_indirect(sig, func, &call_args)
 494         }
 495         _ => bug!("{:?}", fn_ty),
 496     };
 497
 498     match output_pass_mode {
 499         PassMode::NoPass => {}
 500         PassMode::ByVal(_) => {
 501             if let Some((ret_place, _)) = destination {
 502                 let results = fx.bcx.inst_results(call_inst);
 503                 ret_place.write_cvalue(fx, CValue::ByVal(results[0], ret_layout));
 504             }
 505         }
 506         PassMode::ByRef => {}
 507     }
 508     if let Some((_, dest)) = destination {
 509         let ret_ebb = fx.get_ebb(dest);
 510         fx.bcx.ins().jump(ret_ebb, &[]);
 511     } else {
 512         fx.bcx.ins().trap(TrapCode::User(!0));
 513     }
 514 }
 515
 516 pub fn codegen_return(fx: &mut FunctionCx<impl Backend>) {
 517     match get_pass_mode(fx.tcx, fx.self_sig().abi, fx.return_type(), true) {
 518         PassMode::NoPass | PassMode::ByRef => {
 519             fx.bcx.ins().return_(&[]);
 520         }
 521         PassMode::ByVal(_) => {
 522             let place = fx.get_local_place(RETURN_PLACE);
 523             let ret_val = place.to_cvalue(fx).load_value(fx);
 524             fx.bcx.ins().return_(&[ret_val]);
 525         }
 526     }
 527 }
 528
 529 fn codegen_intrinsic_call<'a, 'tcx: 'a>(
 530     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 531     fn_ty: Ty<'tcx>,
 532     sig: FnSig<'tcx>,
 533     args: &[CValue<'tcx>],
 534     destination: Option<(CPlace<'tcx>, BasicBlock)>,
 535 ) -> bool {
 536     if let ty::FnDef(def_id, substs) = fn_ty.sty {
 537         if sig.abi == Abi::RustIntrinsic {
 538             let intrinsic = fx.tcx.item_name(def_id).as_str();
 539             let intrinsic = &intrinsic[..];
 540
 541             let ret = match destination {
 542                 Some((place, _)) => place,
 543                 None => {
 544                     // Insert non returning intrinsics here
 545                     match intrinsic {
 546                         "abort" => {
 547                             fx.bcx.ins().trap(TrapCode::User(!0 - 1));
 548                         }
 549                         "unreachable" => {
 550                             fx.bcx.ins().trap(TrapCode::User(!0 - 1));
 551                         }
 552                         _ => unimplemented!("unsupported instrinsic {}", intrinsic),
 553                     }
 554                     return true;
 555                 }
 556             };
 557
 558             let nil_ty = fx.tcx.mk_nil();
 559             let u64_layout = fx.layout_of(fx.tcx.types.u64);
 560             let usize_layout = fx.layout_of(fx.tcx.types.usize);
 561
 562             match intrinsic {
 563                 "assume" => {
 564                     assert_eq!(args.len(), 1);
 565                 }
 566                 "arith_offset" => {
 567                     assert_eq!(args.len(), 2);
 568                     let base = args[0].load_value(fx);
 569                     let offset = args[1].load_value(fx);
 570                     let res = fx.bcx.ins().iadd(base, offset);
 571                     let res = CValue::ByVal(res, ret.layout());
 572                     ret.write_cvalue(fx, res);
 573                 }
 574                 "likely" | "unlikely" => {
 575                     assert_eq!(args.len(), 1);
 576                     ret.write_cvalue(fx, args[0]);
 577                 }
 578                 "copy" | "copy_nonoverlapping" => {
 579                     let elem_ty = substs.type_at(0);
 580                     let elem_size: u64 = fx.layout_of(elem_ty).size.bytes();
 581                     let elem_size = fx
 582                         .bcx
 583                         .ins()
 584                         .iconst(fx.module.pointer_type(), elem_size as i64);
 585                     assert_eq!(args.len(), 3);
 586                     let src = args[0];
 587                     let dst = args[1];
 588                     let count = args[2].load_value(fx);
 589                     let byte_amount = fx.bcx.ins().imul(count, elem_size);
 590                     fx.easy_call(
 591                         "memmove",
 592                         &[dst, src, CValue::ByVal(byte_amount, usize_layout)],
 593                         nil_ty,
 594                     );
 595                 }
 596                 "discriminant_value" => {
 597                     assert_eq!(args.len(), 1);
 598                     let discr = crate::base::trans_get_discriminant(fx, args[0], ret.layout());
 599                     ret.write_cvalue(fx, discr);
 600                 }
 601                 "size_of" => {
 602                     assert_eq!(args.len(), 0);
 603                     let size_of = fx.layout_of(substs.type_at(0)).size.bytes();
 604                     let size_of = CValue::const_val(fx, usize_layout.ty, size_of as i64);
 605                     ret.write_cvalue(fx, size_of);
 606                 }
 607                 "size_of_val" => {
 608                     assert_eq!(args.len(), 1);
 609                     let size = match &substs.type_at(0).sty {
 610                         ty::Slice(elem) => {
 611                             let len = args[0].load_value_pair(fx).1;
 612                             let elem_size = fx.layout_of(elem).size.bytes();
 613                             fx.bcx.ins().imul_imm(len, elem_size as i64)
 614                         },
 615                         ty => unimplemented!("size_of_val for {:?}", ty),
 616                     };
 617                     ret.write_cvalue(fx, CValue::ByVal(size, usize_layout));
 618                 }
 619                 "type_id" => {
 620                     assert_eq!(args.len(), 0);
 621                     let type_id = fx.tcx.type_id_hash(substs.type_at(0));
 622                     let type_id = CValue::const_val(fx, u64_layout.ty, type_id as i64);
 623                     ret.write_cvalue(fx, type_id);
 624                 }
 625                 "min_align_of" => {
 626                     assert_eq!(args.len(), 0);
 627                     let min_align = fx.layout_of(substs.type_at(0)).align.abi();
 628                     let min_align = CValue::const_val(fx, usize_layout.ty, min_align as i64);
 629                     ret.write_cvalue(fx, min_align);
 630                 }
 631                 _ if intrinsic.starts_with("unchecked_") => {
 632                     assert_eq!(args.len(), 2);
 633                     let bin_op = match intrinsic {
 634                         "unchecked_div" => BinOp::Div,
 635                         "unchecked_rem" => BinOp::Rem,
 636                         "unchecked_shl" => BinOp::Shl,
 637                         "unchecked_shr" => BinOp::Shr,
 638                         _ => unimplemented!("intrinsic {}", intrinsic),
 639                     };
 640                     let res = match ret.layout().ty.sty {
 641                         ty::Uint(_) => crate::base::trans_int_binop(
 642                             fx,
 643                             bin_op,
 644                             args[0],
 645                             args[1],
 646                             ret.layout().ty,
 647                             false,
 648                         ),
 649                         ty::Int(_) => crate::base::trans_int_binop(
 650                             fx,
 651                             bin_op,
 652                             args[0],
 653                             args[1],
 654                             ret.layout().ty,
 655                             true,
 656                         ),
 657                         _ => panic!(),
 658                     };
 659                     ret.write_cvalue(fx, res);
 660                 }
 661                 _ if intrinsic.ends_with("_with_overflow") => {
 662                     assert_eq!(args.len(), 2);
 663                     assert_eq!(args[0].layout().ty, args[1].layout().ty);
 664                     let bin_op = match intrinsic {
 665                         "add_with_overflow" => BinOp::Add,
 666                         "sub_with_overflow" => BinOp::Sub,
 667                         "mul_with_overflow" => BinOp::Mul,
 668                         _ => unimplemented!("intrinsic {}", intrinsic),
 669                     };
 670                     let res = match args[0].layout().ty.sty {
 671                         ty::Uint(_) => crate::base::trans_checked_int_binop(
 672                             fx,
 673                             bin_op,
 674                             args[0],
 675                             args[1],
 676                             ret.layout().ty,
 677                             false,
 678                         ),
 679                         ty::Int(_) => crate::base::trans_checked_int_binop(
 680                             fx,
 681                             bin_op,
 682                             args[0],
 683                             args[1],
 684                             ret.layout().ty,
 685                             true,
 686                         ),
 687                         _ => panic!(),
 688                     };
 689                     ret.write_cvalue(fx, res);
 690                 }
 691                 _ if intrinsic.starts_with("overflowing_") => {
 692                     assert_eq!(args.len(), 2);
 693                     assert_eq!(args[0].layout().ty, args[1].layout().ty);
 694                     let bin_op = match intrinsic {
 695                         "overflowing_add" => BinOp::Add,
 696                         "overflowing_sub" => BinOp::Sub,
 697                         "overflowing_mul" => BinOp::Mul,
 698                         _ => unimplemented!("intrinsic {}", intrinsic),
 699                     };
 700                     let res = match args[0].layout().ty.sty {
 701                         ty::Uint(_) => crate::base::trans_int_binop(
 702                             fx,
 703                             bin_op,
 704                             args[0],
 705                             args[1],
 706                             ret.layout().ty,
 707                             false,
 708                         ),
 709                         ty::Int(_) => crate::base::trans_int_binop(
 710                             fx,
 711                             bin_op,
 712                             args[0],
 713                             args[1],
 714                             ret.layout().ty,
 715                             true,
 716                         ),
 717                         _ => panic!(),
 718                     };
 719                     ret.write_cvalue(fx, res);
 720                 }
 721                 "offset" => {
 722                     assert_eq!(args.len(), 2);
 723                     let base = args[0].load_value(fx);
 724                     let offset = args[1].load_value(fx);
 725                     let res = fx.bcx.ins().iadd(base, offset);
 726                     ret.write_cvalue(fx, CValue::ByVal(res, args[0].layout()));
 727                 }
 728                 "transmute" => {
 729                     assert_eq!(args.len(), 1);
 730                     let src_ty = substs.type_at(0);
 731                     let dst_ty = substs.type_at(1);
 732                     assert_eq!(args[0].layout().ty, src_ty);
 733                     let addr = args[0].force_stack(fx);
 734                     let dst_layout = fx.layout_of(dst_ty);
 735                     ret.write_cvalue(fx, CValue::ByRef(addr, dst_layout))
 736                 }
 737                 "uninit" => {
 738                     assert_eq!(args.len(), 0);
 739                     let ty = substs.type_at(0);
 740                     let layout = fx.layout_of(ty);
 741                     let stack_slot = fx.bcx.create_stack_slot(StackSlotData {
 742                         kind: StackSlotKind::ExplicitSlot,
 743                         size: layout.size.bytes() as u32,
 744                         offset: None,
 745                     });
 746
 747                     let uninit_place = CPlace::from_stack_slot(fx, stack_slot, ty);
 748                     let uninit_val = uninit_place.to_cvalue(fx);
 749                     ret.write_cvalue(fx, uninit_val);
 750                 }
 751                 "ctlz" | "ctlz_nonzero" => {
 752                     assert_eq!(args.len(), 1);
 753                     let arg = args[0].load_value(fx);
 754                     let res = CValue::ByVal(fx.bcx.ins().clz(arg), args[0].layout());
 755                     ret.write_cvalue(fx, res);
 756                 }
 757                 "cttz" | "cttz_nonzero" => {
 758                     assert_eq!(args.len(), 1);
 759                     let arg = args[0].load_value(fx);
 760                     let res = CValue::ByVal(fx.bcx.ins().clz(arg), args[0].layout());
 761                     ret.write_cvalue(fx, res);
 762                 }
 763                 "ctpop" => {
 764                     assert_eq!(args.len(), 1);
 765                     let arg = args[0].load_value(fx);
 766                     let res = CValue::ByVal(fx.bcx.ins().popcnt(arg), args[0].layout());
 767                     ret.write_cvalue(fx, res);
 768                 }
 769                 _ => unimpl!("unsupported intrinsic {}", intrinsic),
 770             }
 771
 772             if let Some((_, dest)) = destination {
 773                 let ret_ebb = fx.get_ebb(dest);
 774                 fx.bcx.ins().jump(ret_ebb, &[]);
 775             } else {
 776                 fx.bcx.ins().trap(TrapCode::User(!0));
 777             }
 778             return true;
 779         }
 780     }
 781
 782     false
 783 }