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