src/abi.rs

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