src/abi/mod.rs

   1 //! Handling of everything related to the calling convention. Also fills `fx.local_map`.
   2
   3 #[cfg(debug_assertions)]
   4 mod comments;
   5 mod pass_mode;
   6 mod returning;
   7
   8 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
   9 use rustc_middle::ty::layout::FnAbiExt;
  10 use rustc_target::abi::call::{Conv, FnAbi};
  11 use rustc_target::spec::abi::Abi;
  12
  13 use cranelift_codegen::ir::AbiParam;
  14 use smallvec::smallvec;
  15
  16 use self::pass_mode::*;
  17 use crate::prelude::*;
  18
  19 pub(crate) use self::returning::{can_return_to_ssa_var, codegen_return};
  20
  21 fn clif_sig_from_fn_abi<'tcx>(
  22     tcx: TyCtxt<'tcx>,
  23     triple: &target_lexicon::Triple,
  24     fn_abi: &FnAbi<'tcx, Ty<'tcx>>,
  25 ) -> Signature {
  26     let call_conv = match fn_abi.conv {
  27         Conv::Rust | Conv::C => CallConv::triple_default(triple),
  28         Conv::X86_64SysV => CallConv::SystemV,
  29         Conv::X86_64Win64 => CallConv::WindowsFastcall,
  30         Conv::ArmAapcs
  31         | Conv::CCmseNonSecureCall
  32         | Conv::Msp430Intr
  33         | Conv::PtxKernel
  34         | Conv::X86Fastcall
  35         | Conv::X86Intr
  36         | Conv::X86Stdcall
  37         | Conv::X86ThisCall
  38         | Conv::X86VectorCall
  39         | Conv::AmdGpuKernel
  40         | Conv::AvrInterrupt
  41         | Conv::AvrNonBlockingInterrupt => todo!("{:?}", fn_abi.conv),
  42     };
  43     let inputs = fn_abi
  44         .args
  45         .iter()
  46         .map(|arg_abi| arg_abi.get_abi_param(tcx).into_iter())
  47         .flatten();
  48
  49     let (return_ptr, returns) = fn_abi.ret.get_abi_return(tcx);
  50     // Sometimes the first param is an pointer to the place where the return value needs to be stored.
  51     let params: Vec<_> = return_ptr.into_iter().chain(inputs).collect();
  52
  53     Signature {
  54         params,
  55         returns,
  56         call_conv,
  57     }
  58 }
  59
  60 pub(crate) fn get_function_sig<'tcx>(
  61     tcx: TyCtxt<'tcx>,
  62     triple: &target_lexicon::Triple,
  63     inst: Instance<'tcx>,
  64 ) -> Signature {
  65     assert!(!inst.substs.needs_infer());
  66     clif_sig_from_fn_abi(
  67         tcx,
  68         triple,
  69         &FnAbi::of_instance(&RevealAllLayoutCx(tcx), inst, &[]),
  70     )
  71 }
  72
  73 /// Instance must be monomorphized
  74 pub(crate) fn import_function<'tcx>(
  75     tcx: TyCtxt<'tcx>,
  76     module: &mut dyn Module,
  77     inst: Instance<'tcx>,
  78 ) -> FuncId {
  79     let name = tcx.symbol_name(inst).name.to_string();
  80     let sig = get_function_sig(tcx, module.isa().triple(), inst);
  81     module
  82         .declare_function(&name, Linkage::Import, &sig)
  83         .unwrap()
  84 }
  85
  86 impl<'tcx> FunctionCx<'_, '_, 'tcx> {
  87     /// Instance must be monomorphized
  88     pub(crate) fn get_function_ref(&mut self, inst: Instance<'tcx>) -> FuncRef {
  89         let func_id = import_function(self.tcx, self.cx.module, inst);
  90         let func_ref = self
  91             .cx
  92             .module
  93             .declare_func_in_func(func_id, &mut self.bcx.func);
  94
  95         #[cfg(debug_assertions)]
  96         self.add_comment(func_ref, format!("{:?}", inst));
  97
  98         func_ref
  99     }
 100
 101     pub(crate) fn lib_call(
 102         &mut self,
 103         name: &str,
 104         params: Vec<AbiParam>,
 105         returns: Vec<AbiParam>,
 106         args: &[Value],
 107     ) -> &[Value] {
 108         let sig = Signature {
 109             params,
 110             returns,
 111             call_conv: CallConv::triple_default(self.triple()),
 112         };
 113         let func_id = self
 114             .cx
 115             .module
 116             .declare_function(&name, Linkage::Import, &sig)
 117             .unwrap();
 118         let func_ref = self
 119             .cx
 120             .module
 121             .declare_func_in_func(func_id, &mut self.bcx.func);
 122         let call_inst = self.bcx.ins().call(func_ref, args);
 123         #[cfg(debug_assertions)]
 124         {
 125             self.add_comment(call_inst, format!("easy_call {}", name));
 126         }
 127         let results = self.bcx.inst_results(call_inst);
 128         assert!(results.len() <= 2, "{}", results.len());
 129         results
 130     }
 131
 132     pub(crate) fn easy_call(
 133         &mut self,
 134         name: &str,
 135         args: &[CValue<'tcx>],
 136         return_ty: Ty<'tcx>,
 137     ) -> CValue<'tcx> {
 138         let (input_tys, args): (Vec<_>, Vec<_>) = args
 139             .iter()
 140             .map(|arg| {
 141                 (
 142                     AbiParam::new(self.clif_type(arg.layout().ty).unwrap()),
 143                     arg.load_scalar(self),
 144                 )
 145             })
 146             .unzip();
 147         let return_layout = self.layout_of(return_ty);
 148         let return_tys = if let ty::Tuple(tup) = return_ty.kind() {
 149             tup.types()
 150                 .map(|ty| AbiParam::new(self.clif_type(ty).unwrap()))
 151                 .collect()
 152         } else {
 153             vec![AbiParam::new(self.clif_type(return_ty).unwrap())]
 154         };
 155         let ret_vals = self.lib_call(name, input_tys, return_tys, &args);
 156         match *ret_vals {
 157             [] => CValue::by_ref(
 158                 Pointer::const_addr(self, i64::from(self.pointer_type.bytes())),
 159                 return_layout,
 160             ),
 161             [val] => CValue::by_val(val, return_layout),
 162             [val, extra] => CValue::by_val_pair(val, extra, return_layout),
 163             _ => unreachable!(),
 164         }
 165     }
 166 }
 167
 168 /// Make a [`CPlace`] capable of holding value of the specified type.
 169 fn make_local_place<'tcx>(
 170     fx: &mut FunctionCx<'_, '_, 'tcx>,
 171     local: Local,
 172     layout: TyAndLayout<'tcx>,
 173     is_ssa: bool,
 174 ) -> CPlace<'tcx> {
 175     let place = if is_ssa {
 176         if let rustc_target::abi::Abi::ScalarPair(_, _) = layout.abi {
 177             CPlace::new_var_pair(fx, local, layout)
 178         } else {
 179             CPlace::new_var(fx, local, layout)
 180         }
 181     } else {
 182         CPlace::new_stack_slot(fx, layout)
 183     };
 184
 185     #[cfg(debug_assertions)]
 186     self::comments::add_local_place_comments(fx, place, local);
 187
 188     place
 189 }
 190
 191 pub(crate) fn codegen_fn_prelude<'tcx>(fx: &mut FunctionCx<'_, '_, 'tcx>, start_block: Block) {
 192     fx.bcx.append_block_params_for_function_params(start_block);
 193
 194     fx.bcx.switch_to_block(start_block);
 195     fx.bcx.ins().nop();
 196
 197     let ssa_analyzed = crate::analyze::analyze(fx);
 198
 199     #[cfg(debug_assertions)]
 200     self::comments::add_args_header_comment(fx);
 201
 202     let mut block_params_iter = fx
 203         .bcx
 204         .func
 205         .dfg
 206         .block_params(start_block)
 207         .to_vec()
 208         .into_iter();
 209     let ret_place =
 210         self::returning::codegen_return_param(fx, &ssa_analyzed, &mut block_params_iter);
 211     assert_eq!(fx.local_map.push(ret_place), RETURN_PLACE);
 212
 213     // None means pass_mode == NoPass
 214     enum ArgKind<'tcx> {
 215         Normal(Option<CValue<'tcx>>),
 216         Spread(Vec<Option<CValue<'tcx>>>),
 217     }
 218
 219     let fn_abi = fx.fn_abi.take().unwrap();
 220     let mut arg_abis_iter = fn_abi.args.iter();
 221
 222     let func_params = fx
 223         .mir
 224         .args_iter()
 225         .map(|local| {
 226             let arg_ty = fx.monomorphize(fx.mir.local_decls[local].ty);
 227
 228             // Adapted from https://github.com/rust-lang/rust/blob/145155dc96757002c7b2e9de8489416e2fdbbd57/src/librustc_codegen_llvm/mir/mod.rs#L442-L482
 229             if Some(local) == fx.mir.spread_arg {
 230                 // This argument (e.g. the last argument in the "rust-call" ABI)
 231                 // is a tuple that was spread at the ABI level and now we have
 232                 // to reconstruct it into a tuple local variable, from multiple
 233                 // individual function arguments.
 234
 235                 let tupled_arg_tys = match arg_ty.kind() {
 236                     ty::Tuple(ref tys) => tys,
 237                     _ => bug!("spread argument isn't a tuple?! but {:?}", arg_ty),
 238                 };
 239
 240                 let mut params = Vec::new();
 241                 for (i, _arg_ty) in tupled_arg_tys.types().enumerate() {
 242                     let arg_abi = arg_abis_iter.next().unwrap();
 243                     let param =
 244                         cvalue_for_param(fx, Some(local), Some(i), arg_abi, &mut block_params_iter);
 245                     params.push(param);
 246                 }
 247
 248                 (local, ArgKind::Spread(params), arg_ty)
 249             } else {
 250                 let arg_abi = arg_abis_iter.next().unwrap();
 251                 let param =
 252                     cvalue_for_param(fx, Some(local), None, arg_abi, &mut block_params_iter);
 253                 (local, ArgKind::Normal(param), arg_ty)
 254             }
 255         })
 256         .collect::<Vec<(Local, ArgKind<'tcx>, Ty<'tcx>)>>();
 257
 258     assert!(fx.caller_location.is_none());
 259     if fx.instance.def.requires_caller_location(fx.tcx) {
 260         // Store caller location for `#[track_caller]`.
 261         let arg_abi = arg_abis_iter.next().unwrap();
 262         fx.caller_location =
 263             Some(cvalue_for_param(fx, None, None, arg_abi, &mut block_params_iter).unwrap());
 264     }
 265
 266     assert!(arg_abis_iter.next().is_none(), "ArgAbi left behind");
 267     fx.fn_abi = Some(fn_abi);
 268     assert!(block_params_iter.next().is_none(), "arg_value left behind");
 269
 270     #[cfg(debug_assertions)]
 271     self::comments::add_locals_header_comment(fx);
 272
 273     for (local, arg_kind, ty) in func_params {
 274         let layout = fx.layout_of(ty);
 275
 276         let is_ssa = ssa_analyzed[local] == crate::analyze::SsaKind::Ssa;
 277
 278         // While this is normally an optimization to prevent an unnecessary copy when an argument is
 279         // not mutated by the current function, this is necessary to support unsized arguments.
 280         if let ArgKind::Normal(Some(val)) = arg_kind {
 281             if let Some((addr, meta)) = val.try_to_ptr() {
 282                 let local_decl = &fx.mir.local_decls[local];
 283                 //                       v this ! is important
 284                 let internally_mutable = !val.layout().ty.is_freeze(
 285                     fx.tcx.at(local_decl.source_info.span),
 286                     ParamEnv::reveal_all(),
 287                 );
 288                 if local_decl.mutability == mir::Mutability::Not && !internally_mutable {
 289                     // We wont mutate this argument, so it is fine to borrow the backing storage
 290                     // of this argument, to prevent a copy.
 291
 292                     let place = if let Some(meta) = meta {
 293                         CPlace::for_ptr_with_extra(addr, meta, val.layout())
 294                     } else {
 295                         CPlace::for_ptr(addr, val.layout())
 296                     };
 297
 298                     #[cfg(debug_assertions)]
 299                     self::comments::add_local_place_comments(fx, place, local);
 300
 301                     assert_eq!(fx.local_map.push(place), local);
 302                     continue;
 303                 }
 304             }
 305         }
 306
 307         let place = make_local_place(fx, local, layout, is_ssa);
 308         assert_eq!(fx.local_map.push(place), local);
 309
 310         match arg_kind {
 311             ArgKind::Normal(param) => {
 312                 if let Some(param) = param {
 313                     place.write_cvalue(fx, param);
 314                 }
 315             }
 316             ArgKind::Spread(params) => {
 317                 for (i, param) in params.into_iter().enumerate() {
 318                     if let Some(param) = param {
 319                         place
 320                             .place_field(fx, mir::Field::new(i))
 321                             .write_cvalue(fx, param);
 322                     }
 323                 }
 324             }
 325         }
 326     }
 327
 328     for local in fx.mir.vars_and_temps_iter() {
 329         let ty = fx.monomorphize(fx.mir.local_decls[local].ty);
 330         let layout = fx.layout_of(ty);
 331
 332         let is_ssa = ssa_analyzed[local] == crate::analyze::SsaKind::Ssa;
 333
 334         let place = make_local_place(fx, local, layout, is_ssa);
 335         assert_eq!(fx.local_map.push(place), local);
 336     }
 337
 338     fx.bcx
 339         .ins()
 340         .jump(*fx.block_map.get(START_BLOCK).unwrap(), &[]);
 341 }
 342
 343 pub(crate) fn codegen_terminator_call<'tcx>(
 344     fx: &mut FunctionCx<'_, '_, 'tcx>,
 345     span: Span,
 346     current_block: Block,
 347     func: &Operand<'tcx>,
 348     args: &[Operand<'tcx>],
 349     destination: Option<(Place<'tcx>, BasicBlock)>,
 350 ) {
 351     let fn_ty = fx.monomorphize(func.ty(fx.mir, fx.tcx));
 352     let fn_sig = fx
 353         .tcx
 354         .normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), fn_ty.fn_sig(fx.tcx));
 355
 356     let destination = destination.map(|(place, bb)| (codegen_place(fx, place), bb));
 357
 358     // Handle special calls like instrinsics and empty drop glue.
 359     let instance = if let ty::FnDef(def_id, substs) = *fn_ty.kind() {
 360         let instance = ty::Instance::resolve(fx.tcx, ty::ParamEnv::reveal_all(), def_id, substs)
 361             .unwrap()
 362             .unwrap()
 363             .polymorphize(fx.tcx);
 364
 365         if fx.tcx.symbol_name(instance).name.starts_with("llvm.") {
 366             crate::intrinsics::codegen_llvm_intrinsic_call(
 367                 fx,
 368                 &fx.tcx.symbol_name(instance).name,
 369                 substs,
 370                 args,
 371                 destination,
 372             );
 373             return;
 374         }
 375
 376         match instance.def {
 377             InstanceDef::Intrinsic(_) => {
 378                 crate::intrinsics::codegen_intrinsic_call(fx, instance, args, destination, span);
 379                 return;
 380             }
 381             InstanceDef::DropGlue(_, None) => {
 382                 // empty drop glue - a nop.
 383                 let (_, dest) = destination.expect("Non terminating drop_in_place_real???");
 384                 let ret_block = fx.get_block(dest);
 385                 fx.bcx.ins().jump(ret_block, &[]);
 386                 return;
 387             }
 388             _ => Some(instance),
 389         }
 390     } else {
 391         None
 392     };
 393
 394     let extra_args = &args[fn_sig.inputs().len()..];
 395     let extra_args = extra_args
 396         .iter()
 397         .map(|op_arg| fx.monomorphize(op_arg.ty(fx.mir, fx.tcx)))
 398         .collect::<Vec<_>>();
 399     let fn_abi = if let Some(instance) = instance {
 400         FnAbi::of_instance(&RevealAllLayoutCx(fx.tcx), instance, &extra_args)
 401     } else {
 402         FnAbi::of_fn_ptr(
 403             &RevealAllLayoutCx(fx.tcx),
 404             fn_ty.fn_sig(fx.tcx),
 405             &extra_args,
 406         )
 407     };
 408
 409     let is_cold = instance
 410         .map(|inst| {
 411             fx.tcx
 412                 .codegen_fn_attrs(inst.def_id())
 413                 .flags
 414                 .contains(CodegenFnAttrFlags::COLD)
 415         })
 416         .unwrap_or(false);
 417     if is_cold {
 418         fx.cold_blocks.insert(current_block);
 419     }
 420
 421     // Unpack arguments tuple for closures
 422     let args = if fn_sig.abi == Abi::RustCall {
 423         assert_eq!(args.len(), 2, "rust-call abi requires two arguments");
 424         let self_arg = codegen_operand(fx, &args[0]);
 425         let pack_arg = codegen_operand(fx, &args[1]);
 426
 427         let tupled_arguments = match pack_arg.layout().ty.kind() {
 428             ty::Tuple(ref tupled_arguments) => tupled_arguments,
 429             _ => bug!("argument to function with \"rust-call\" ABI is not a tuple"),
 430         };
 431
 432         let mut args = Vec::with_capacity(1 + tupled_arguments.len());
 433         args.push(self_arg);
 434         for i in 0..tupled_arguments.len() {
 435             args.push(pack_arg.value_field(fx, mir::Field::new(i)));
 436         }
 437         args
 438     } else {
 439         args.iter()
 440             .map(|arg| codegen_operand(fx, arg))
 441             .collect::<Vec<_>>()
 442     };
 443
 444     //   | indirect call target
 445     //   |         | the first argument to be passed
 446     //   v         v
 447     let (func_ref, first_arg) = match instance {
 448         // Trait object call
 449         Some(Instance {
 450             def: InstanceDef::Virtual(_, idx),
 451             ..
 452         }) => {
 453             #[cfg(debug_assertions)]
 454             {
 455                 let nop_inst = fx.bcx.ins().nop();
 456                 fx.add_comment(
 457                     nop_inst,
 458                     format!("virtual call; self arg pass mode: {:?}", &fn_abi.args[0],),
 459                 );
 460             }
 461             let (ptr, method) = crate::vtable::get_ptr_and_method_ref(fx, args[0], idx);
 462             (Some(method), smallvec![ptr])
 463         }
 464
 465         // Normal call
 466         Some(_) => (
 467             None,
 468             args.get(0)
 469                 .map(|arg| adjust_arg_for_abi(fx, *arg, &fn_abi.args[0]))
 470                 .unwrap_or(smallvec![]),
 471         ),
 472
 473         // Indirect call
 474         None => {
 475             #[cfg(debug_assertions)]
 476             {
 477                 let nop_inst = fx.bcx.ins().nop();
 478                 fx.add_comment(nop_inst, "indirect call");
 479             }
 480             let func = codegen_operand(fx, func).load_scalar(fx);
 481             (
 482                 Some(func),
 483                 args.get(0)
 484                     .map(|arg| adjust_arg_for_abi(fx, *arg, &fn_abi.args[0]))
 485                     .unwrap_or(smallvec![]),
 486             )
 487         }
 488     };
 489
 490     let ret_place = destination.map(|(place, _)| place);
 491     let (call_inst, call_args) = self::returning::codegen_with_call_return_arg(
 492         fx,
 493         &fn_abi.ret,
 494         ret_place,
 495         |fx, return_ptr| {
 496             let regular_args_count = args.len();
 497             let mut call_args: Vec<Value> = return_ptr
 498                 .into_iter()
 499                 .chain(first_arg.into_iter())
 500                 .chain(
 501                     args.into_iter()
 502                         .enumerate()
 503                         .skip(1)
 504                         .map(|(i, arg)| adjust_arg_for_abi(fx, arg, &fn_abi.args[i]).into_iter())
 505                         .flatten(),
 506                 )
 507                 .collect::<Vec<_>>();
 508
 509             if instance
 510                 .map(|inst| inst.def.requires_caller_location(fx.tcx))
 511                 .unwrap_or(false)
 512             {
 513                 // Pass the caller location for `#[track_caller]`.
 514                 let caller_location = fx.get_caller_location(span);
 515                 call_args.extend(
 516                     adjust_arg_for_abi(fx, caller_location, &fn_abi.args[regular_args_count])
 517                         .into_iter(),
 518                 );
 519                 assert_eq!(fn_abi.args.len(), regular_args_count + 1);
 520             } else {
 521                 assert_eq!(fn_abi.args.len(), regular_args_count);
 522             }
 523
 524             let call_inst = if let Some(func_ref) = func_ref {
 525                 let sig = clif_sig_from_fn_abi(fx.tcx, fx.triple(), &fn_abi);
 526                 let sig = fx.bcx.import_signature(sig);
 527                 fx.bcx.ins().call_indirect(sig, func_ref, &call_args)
 528             } else {
 529                 let func_ref =
 530                     fx.get_function_ref(instance.expect("non-indirect call on non-FnDef type"));
 531                 fx.bcx.ins().call(func_ref, &call_args)
 532             };
 533
 534             (call_inst, call_args)
 535         },
 536     );
 537
 538     // FIXME find a cleaner way to support varargs
 539     if fn_sig.c_variadic {
 540         if fn_sig.abi != Abi::C {
 541             fx.tcx.sess.span_fatal(
 542                 span,
 543                 &format!("Variadic call for non-C abi {:?}", fn_sig.abi),
 544             );
 545         }
 546         let sig_ref = fx.bcx.func.dfg.call_signature(call_inst).unwrap();
 547         let abi_params = call_args
 548             .into_iter()
 549             .map(|arg| {
 550                 let ty = fx.bcx.func.dfg.value_type(arg);
 551                 if !ty.is_int() {
 552                     // FIXME set %al to upperbound on float args once floats are supported
 553                     fx.tcx
 554                         .sess
 555                         .span_fatal(span, &format!("Non int ty {:?} for variadic call", ty));
 556                 }
 557                 AbiParam::new(ty)
 558             })
 559             .collect::<Vec<AbiParam>>();
 560         fx.bcx.func.dfg.signatures[sig_ref].params = abi_params;
 561     }
 562
 563     if let Some((_, dest)) = destination {
 564         let ret_block = fx.get_block(dest);
 565         fx.bcx.ins().jump(ret_block, &[]);
 566     } else {
 567         trap_unreachable(fx, "[corruption] Diverging function returned");
 568     }
 569 }
 570
 571 pub(crate) fn codegen_drop<'tcx>(
 572     fx: &mut FunctionCx<'_, '_, 'tcx>,
 573     span: Span,
 574     drop_place: CPlace<'tcx>,
 575 ) {
 576     let ty = drop_place.layout().ty;
 577     let drop_instance = Instance::resolve_drop_in_place(fx.tcx, ty).polymorphize(fx.tcx);
 578
 579     if let ty::InstanceDef::DropGlue(_, None) = drop_instance.def {
 580         // we don't actually need to drop anything
 581     } else {
 582         match ty.kind() {
 583             ty::Dynamic(..) => {
 584                 let (ptr, vtable) = drop_place.to_ptr_maybe_unsized();
 585                 let ptr = ptr.get_addr(fx);
 586                 let drop_fn = crate::vtable::drop_fn_of_obj(fx, vtable.unwrap());
 587
 588                 // FIXME(eddyb) perhaps move some of this logic into
 589                 // `Instance::resolve_drop_in_place`?
 590                 let virtual_drop = Instance {
 591                     def: ty::InstanceDef::Virtual(drop_instance.def_id(), 0),
 592                     substs: drop_instance.substs,
 593                 };
 594                 let fn_abi = FnAbi::of_instance(&RevealAllLayoutCx(fx.tcx), virtual_drop, &[]);
 595
 596                 let sig = clif_sig_from_fn_abi(fx.tcx, fx.triple(), &fn_abi);
 597                 let sig = fx.bcx.import_signature(sig);
 598                 fx.bcx.ins().call_indirect(sig, drop_fn, &[ptr]);
 599             }
 600             _ => {
 601                 assert!(!matches!(drop_instance.def, InstanceDef::Virtual(_, _)));
 602
 603                 let fn_abi = FnAbi::of_instance(&RevealAllLayoutCx(fx.tcx), drop_instance, &[]);
 604
 605                 let arg_value = drop_place.place_ref(
 606                     fx,
 607                     fx.layout_of(fx.tcx.mk_ref(
 608                         &ty::RegionKind::ReErased,
 609                         TypeAndMut {
 610                             ty,
 611                             mutbl: crate::rustc_hir::Mutability::Mut,
 612                         },
 613                     )),
 614                 );
 615                 let arg_value = adjust_arg_for_abi(fx, arg_value, &fn_abi.args[0]);
 616
 617                 let mut call_args: Vec<Value> = arg_value.into_iter().collect::<Vec<_>>();
 618
 619                 if drop_instance.def.requires_caller_location(fx.tcx) {
 620                     // Pass the caller location for `#[track_caller]`.
 621                     let caller_location = fx.get_caller_location(span);
 622                     call_args.extend(
 623                         adjust_arg_for_abi(fx, caller_location, &fn_abi.args[1]).into_iter(),
 624                     );
 625                 }
 626
 627                 let func_ref = fx.get_function_ref(drop_instance);
 628                 fx.bcx.ins().call(func_ref, &call_args);
 629             }
 630         }
 631     }
 632 }