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