src/base.rs

   1 use rustc::ty::adjustment::PointerCast;
   2
   3 use crate::prelude::*;
   4
   5 pub fn trans_fn<'a, 'clif, 'tcx: 'a, B: Backend + 'static>(
   6     cx: &mut crate::CodegenCx<'a, 'clif, 'tcx, B>,
   7     instance: Instance<'tcx>,
   8     linkage: Linkage,
   9 ) {
  10     let tcx = cx.tcx;
  11
  12     // Step 1. Get mir
  13     let mir = tcx.instance_mir(instance.def);
  14
  15     // Step 2. Check fn sig for u128 and i128 and replace those functions with a trap.
  16     {
  17         // FIXME implement u128 and i128 support
  18
  19         // Step 2a. Check sig for u128 and i128
  20         let fn_sig = tcx.normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), &instance.fn_sig(tcx));
  21
  22         struct UI128Visitor<'a, 'tcx: 'a>(TyCtxt<'a, 'tcx, 'tcx>, bool);
  23
  24         impl<'a, 'tcx: 'a> rustc::ty::fold::TypeVisitor<'tcx> for UI128Visitor<'a, 'tcx> {
  25             fn visit_ty(&mut self, t: Ty<'tcx>) -> bool {
  26                 if t.sty == self.0.types.u128.sty || t.sty == self.0.types.i128.sty {
  27                     self.1 = true;
  28                     return false; // stop visiting
  29                 }
  30
  31                 t.super_visit_with(self)
  32             }
  33         }
  34
  35         let mut visitor = UI128Visitor(tcx, false);
  36         fn_sig.visit_with(&mut visitor);
  37
  38         // Step 2b. If found replace function with a trap.
  39         if visitor.1 {
  40             tcx.sess.warn("u128 and i128 are not yet supported. \
  41             Functions using these as args will be replaced with a trap.");
  42
  43             // Step 2b1. Declare function with fake signature
  44             let sig = Signature {
  45                 params: vec![AbiParam::new(types::INVALID)],
  46                 returns: vec![],
  47                 call_conv: CallConv::Fast,
  48             };
  49             let name = tcx.symbol_name(instance).as_str();
  50             let func_id = cx.module.declare_function(&*name, linkage, &sig).unwrap();
  51
  52             // Step 2b2. Create trapping function
  53             let mut func = Function::with_name_signature(ExternalName::user(0, 0), sig);
  54             let mut func_ctx = FunctionBuilderContext::new();
  55             let mut bcx = FunctionBuilder::new(&mut func, &mut func_ctx);
  56             let start_ebb = bcx.create_ebb();
  57             bcx.append_ebb_params_for_function_params(start_ebb);
  58             bcx.switch_to_block(start_ebb);
  59
  60             let mut fx = FunctionCx {
  61                 tcx,
  62                 module: cx.module,
  63                 pointer_type: pointer_ty(tcx),
  64
  65                 instance,
  66                 mir,
  67
  68                 bcx,
  69                 ebb_map: HashMap::new(),
  70                 local_map: HashMap::new(),
  71
  72                 clif_comments: crate::pretty_clif::CommentWriter::new(tcx, instance),
  73                 constants: &mut cx.ccx,
  74                 caches: &mut cx.caches,
  75                 source_info_set: indexmap::IndexSet::new(),
  76             };
  77
  78             crate::trap::trap_unreachable(&mut fx, "[unimplemented] Called function with u128 or i128 as argument.");
  79             fx.bcx.seal_all_blocks();
  80             fx.bcx.finalize();
  81
  82             // Step 2b3. Define function
  83             cx.caches.context.func = func;
  84             cx.module
  85                 .define_function(func_id, &mut cx.caches.context)
  86                 .unwrap();
  87             cx.caches.context.clear();
  88             return;
  89         }
  90     }
  91
  92     // Step 3. Declare function
  93     let (name, sig) = get_function_name_and_sig(tcx, instance, false);
  94     let func_id = cx.module.declare_function(&name, linkage, &sig).unwrap();
  95     let mut debug_context = cx
  96         .debug_context
  97         .as_mut()
  98         .map(|debug_context| FunctionDebugContext::new(tcx, debug_context, mir, &name, &sig));
  99
 100     // Step 4. Make FunctionBuilder
 101     let mut func = Function::with_name_signature(ExternalName::user(0, 0), sig);
 102     let mut func_ctx = FunctionBuilderContext::new();
 103     let mut bcx = FunctionBuilder::new(&mut func, &mut func_ctx);
 104
 105     // Step 5. Predefine ebb's
 106     let start_ebb = bcx.create_ebb();
 107     let mut ebb_map: HashMap<BasicBlock, Ebb> = HashMap::new();
 108     for (bb, _bb_data) in mir.basic_blocks().iter_enumerated() {
 109         ebb_map.insert(bb, bcx.create_ebb());
 110     }
 111
 112     // Step 6. Make FunctionCx
 113     let pointer_type = cx.module.target_config().pointer_type();
 114     let clif_comments = crate::pretty_clif::CommentWriter::new(tcx, instance);
 115
 116     let mut fx = FunctionCx {
 117         tcx,
 118         module: cx.module,
 119         pointer_type,
 120
 121         instance,
 122         mir,
 123
 124         bcx,
 125         ebb_map,
 126         local_map: HashMap::new(),
 127
 128         clif_comments,
 129         constants: &mut cx.ccx,
 130         caches: &mut cx.caches,
 131         source_info_set: indexmap::IndexSet::new(),
 132     };
 133
 134     // Step 7. Codegen function
 135     with_unimpl_span(fx.mir.span, || {
 136         crate::abi::codegen_fn_prelude(&mut fx, start_ebb);
 137         codegen_fn_content(&mut fx);
 138     });
 139     let source_info_set = fx.source_info_set.clone();
 140
 141     // Step 8. Write function to file for debugging
 142     #[cfg(debug_assertions)]
 143     fx.write_clif_file();
 144
 145     // Step 9. Verify function
 146     verify_func(tcx, fx.clif_comments, &func);
 147
 148     // Step 10. Define function
 149     cx.caches.context.func = func;
 150     cx.module
 151         .define_function(func_id, &mut cx.caches.context)
 152         .unwrap();
 153
 154     // Step 11. Define debuginfo for function
 155     let context = &cx.caches.context;
 156     let isa = cx.module.isa();
 157     debug_context
 158         .as_mut()
 159         .map(|x| x.define(tcx, context, isa, &source_info_set));
 160
 161     // Step 12. Clear context to make it usable for the next function
 162     cx.caches.context.clear();
 163 }
 164
 165 fn verify_func(tcx: TyCtxt, writer: crate::pretty_clif::CommentWriter, func: &Function) {
 166     let flags = settings::Flags::new(settings::builder());
 167     match ::cranelift::codegen::verify_function(&func, &flags) {
 168         Ok(_) => {}
 169         Err(err) => {
 170             tcx.sess.err(&format!("{:?}", err));
 171             let pretty_error = ::cranelift::codegen::print_errors::pretty_verifier_error(
 172                 &func,
 173                 None,
 174                 Some(Box::new(&writer)),
 175                 err,
 176             );
 177             tcx.sess
 178                 .fatal(&format!("cranelift verify error:\n{}", pretty_error));
 179         }
 180     }
 181 }
 182
 183 fn codegen_fn_content<'a, 'tcx: 'a>(fx: &mut FunctionCx<'a, 'tcx, impl Backend>) {
 184     for (bb, bb_data) in fx.mir.basic_blocks().iter_enumerated() {
 185         if bb_data.is_cleanup {
 186             // Unwinding after panicking is not supported
 187             continue;
 188         }
 189
 190         let ebb = fx.get_ebb(bb);
 191         fx.bcx.switch_to_block(ebb);
 192
 193         fx.bcx.ins().nop();
 194         for stmt in &bb_data.statements {
 195             fx.set_debug_loc(stmt.source_info);
 196             trans_stmt(fx, ebb, stmt);
 197         }
 198
 199         #[cfg(debug_assertions)]
 200         {
 201             let mut terminator_head = "\n".to_string();
 202             bb_data
 203                 .terminator()
 204                 .kind
 205                 .fmt_head(&mut terminator_head)
 206                 .unwrap();
 207             let inst = fx.bcx.func.layout.last_inst(ebb).unwrap();
 208             fx.add_comment(inst, terminator_head);
 209         }
 210
 211         fx.set_debug_loc(bb_data.terminator().source_info);
 212
 213         match &bb_data.terminator().kind {
 214             TerminatorKind::Goto { target } => {
 215                 let ebb = fx.get_ebb(*target);
 216                 fx.bcx.ins().jump(ebb, &[]);
 217             }
 218             TerminatorKind::Return => {
 219                 crate::abi::codegen_return(fx);
 220             }
 221             TerminatorKind::Assert {
 222                 cond,
 223                 expected,
 224                 msg,
 225                 target,
 226                 cleanup: _,
 227             } => {
 228                 let cond = trans_operand(fx, cond).load_scalar(fx);
 229                 // TODO HACK brz/brnz for i8/i16 is not yet implemented
 230                 let cond = fx.bcx.ins().uextend(types::I32, cond);
 231                 let target = fx.get_ebb(*target);
 232                 if *expected {
 233                     fx.bcx.ins().brnz(cond, target, &[]);
 234                 } else {
 235                     fx.bcx.ins().brz(cond, target, &[]);
 236                 };
 237                 trap_panic(fx, format!("[panic] Assert {:?} failed.", msg));
 238             }
 239
 240             TerminatorKind::SwitchInt {
 241                 discr,
 242                 switch_ty: _,
 243                 values,
 244                 targets,
 245             } => {
 246                 let discr = trans_operand(fx, discr).load_scalar(fx);
 247                 let mut switch = ::cranelift::frontend::Switch::new();
 248                 for (i, value) in values.iter().enumerate() {
 249                     let ebb = fx.get_ebb(targets[i]);
 250                     switch.set_entry(*value as u64, ebb);
 251                 }
 252                 let otherwise_ebb = fx.get_ebb(targets[targets.len() - 1]);
 253                 switch.emit(&mut fx.bcx, discr, otherwise_ebb);
 254             }
 255             TerminatorKind::Call {
 256                 func,
 257                 args,
 258                 destination,
 259                 cleanup: _,
 260                 from_hir_call: _,
 261             } => {
 262                 crate::abi::codegen_terminator_call(fx, func, args, destination);
 263             }
 264             TerminatorKind::Resume | TerminatorKind::Abort => {
 265                 trap_unreachable(fx, "[corruption] Unwinding bb reached.");
 266             }
 267             TerminatorKind::Unreachable => {
 268                 trap_unreachable(fx, "[corruption] Hit unreachable code.");
 269             }
 270             TerminatorKind::Yield { .. }
 271             | TerminatorKind::FalseEdges { .. }
 272             | TerminatorKind::FalseUnwind { .. }
 273             | TerminatorKind::DropAndReplace { .. }
 274             | TerminatorKind::GeneratorDrop => {
 275                 bug!("shouldn't exist at trans {:?}", bb_data.terminator());
 276             }
 277             TerminatorKind::Drop {
 278                 location,
 279                 target,
 280                 unwind: _,
 281             } => {
 282                 let ty = location.ty(fx.mir, fx.tcx).ty;
 283                 let ty = fx.monomorphize(&ty);
 284                 let drop_fn = crate::rustc_mir::monomorphize::resolve_drop_in_place(fx.tcx, ty);
 285
 286                 if let ty::InstanceDef::DropGlue(_, None) = drop_fn.def {
 287                     // we don't actually need to drop anything
 288                 } else {
 289                     let drop_place = trans_place(fx, location);
 290                     let drop_fn_ty = drop_fn.ty(fx.tcx);
 291                     match ty.sty {
 292                         ty::Dynamic(..) => {
 293                             crate::abi::codegen_drop(fx, drop_place, drop_fn_ty);
 294                         }
 295                         _ => {
 296                             let arg_place = CPlace::new_stack_slot(
 297                                 fx,
 298                                 fx.tcx.mk_ref(
 299                                     &ty::RegionKind::ReErased,
 300                                     TypeAndMut {
 301                                         ty,
 302                                         mutbl: crate::rustc::hir::Mutability::MutMutable,
 303                                     },
 304                                 ),
 305                             );
 306                             drop_place.write_place_ref(fx, arg_place);
 307                             let arg_value = arg_place.to_cvalue(fx);
 308                             crate::abi::codegen_call_inner(
 309                                 fx,
 310                                 None,
 311                                 drop_fn_ty,
 312                                 vec![arg_value],
 313                                 None,
 314                             );
 315                         }
 316                     }
 317                 }
 318
 319                 let target_ebb = fx.get_ebb(*target);
 320                 fx.bcx.ins().jump(target_ebb, &[]);
 321             }
 322         };
 323     }
 324
 325     fx.bcx.seal_all_blocks();
 326     fx.bcx.finalize();
 327 }
 328
 329 fn trans_stmt<'a, 'tcx: 'a>(
 330     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 331     cur_ebb: Ebb,
 332     stmt: &Statement<'tcx>,
 333 ) {
 334     let _print_guard = PrintOnPanic(|| format!("stmt {:?}", stmt));
 335
 336     fx.set_debug_loc(stmt.source_info);
 337
 338     #[cfg(debug_assertions)]
 339     match &stmt.kind {
 340         StatementKind::StorageLive(..) | StatementKind::StorageDead(..) => {} // Those are not very useful
 341         _ => {
 342             let inst = fx.bcx.func.layout.last_inst(cur_ebb).unwrap();
 343             fx.add_comment(inst, format!("{:?}", stmt));
 344         }
 345     }
 346
 347     match &stmt.kind {
 348         StatementKind::SetDiscriminant {
 349             place,
 350             variant_index,
 351         } => {
 352             let place = trans_place(fx, place);
 353             let layout = place.layout();
 354             if layout.for_variant(&*fx, *variant_index).abi == layout::Abi::Uninhabited {
 355                 return;
 356             }
 357             match layout.variants {
 358                 layout::Variants::Single { index } => {
 359                     assert_eq!(index, *variant_index);
 360                 }
 361                 layout::Variants::Multiple {
 362                     discr: _,
 363                     discr_index,
 364                     discr_kind: layout::DiscriminantKind::Tag,
 365                     variants: _,
 366                 } => {
 367                     let ptr = place.place_field(fx, mir::Field::new(discr_index));
 368                     let to = layout
 369                         .ty
 370                         .ty_adt_def()
 371                         .unwrap()
 372                         .discriminant_for_variant(fx.tcx, *variant_index)
 373                         .val;
 374                     let discr = CValue::const_val(fx, ptr.layout().ty, to as u64 as i64);
 375                     ptr.write_cvalue(fx, discr);
 376                 }
 377                 layout::Variants::Multiple {
 378                     discr: _,
 379                     discr_index,
 380                     discr_kind: layout::DiscriminantKind::Niche {
 381                         dataful_variant,
 382                         ref niche_variants,
 383                         niche_start,
 384                     },
 385                     variants: _,
 386                 } => {
 387                     if *variant_index != dataful_variant {
 388                         let niche = place.place_field(fx, mir::Field::new(discr_index));
 389                         //let niche_llty = niche.layout.immediate_llvm_type(bx.cx);
 390                         let niche_value =
 391                             ((variant_index.as_u32() - niche_variants.start().as_u32()) as u128)
 392                                 .wrapping_add(niche_start);
 393                         // FIXME(eddyb) Check the actual primitive type here.
 394                         let niche_llval = if niche_value == 0 {
 395                             CValue::const_val(fx, niche.layout().ty, 0)
 396                         } else {
 397                             CValue::const_val(fx, niche.layout().ty, niche_value as u64 as i64)
 398                         };
 399                         niche.write_cvalue(fx, niche_llval);
 400                     }
 401                 }
 402             }
 403         }
 404         StatementKind::Assign(to_place, rval) => {
 405             let lval = trans_place(fx, to_place);
 406             let dest_layout = lval.layout();
 407             match &**rval {
 408                 Rvalue::Use(operand) => {
 409                     let val = trans_operand(fx, operand);
 410                     lval.write_cvalue(fx, val);
 411                 }
 412                 Rvalue::Ref(_, _, place) => {
 413                     let place = trans_place(fx, place);
 414                     place.write_place_ref(fx, lval);
 415                 }
 416                 Rvalue::BinaryOp(bin_op, lhs, rhs) => {
 417                     let ty = fx.monomorphize(&lhs.ty(fx.mir, fx.tcx));
 418                     let lhs = trans_operand(fx, lhs);
 419                     let rhs = trans_operand(fx, rhs);
 420
 421                     let res = match ty.sty {
 422                         ty::Bool => trans_bool_binop(fx, *bin_op, lhs, rhs, lval.layout().ty),
 423                         ty::Uint(_) => {
 424                             trans_int_binop(fx, *bin_op, lhs, rhs, lval.layout().ty, false)
 425                         }
 426                         ty::Int(_) => {
 427                             trans_int_binop(fx, *bin_op, lhs, rhs, lval.layout().ty, true)
 428                         }
 429                         ty::Float(_) => trans_float_binop(fx, *bin_op, lhs, rhs, lval.layout().ty),
 430                         ty::Char => trans_char_binop(fx, *bin_op, lhs, rhs, lval.layout().ty),
 431                         ty::RawPtr(..) => trans_ptr_binop(fx, *bin_op, lhs, rhs, lval.layout().ty),
 432                         ty::FnPtr(..) => trans_ptr_binop(fx, *bin_op, lhs, rhs, lval.layout().ty),
 433                         _ => unimplemented!("binop {:?} for {:?}", bin_op, ty),
 434                     };
 435                     lval.write_cvalue(fx, res);
 436                 }
 437                 Rvalue::CheckedBinaryOp(bin_op, lhs, rhs) => {
 438                     let ty = fx.monomorphize(&lhs.ty(fx.mir, fx.tcx));
 439                     let lhs = trans_operand(fx, lhs);
 440                     let rhs = trans_operand(fx, rhs);
 441
 442                     let res = match ty.sty {
 443                         ty::Uint(_) => {
 444                             trans_checked_int_binop(fx, *bin_op, lhs, rhs, lval.layout().ty, false)
 445                         }
 446                         ty::Int(_) => {
 447                             trans_checked_int_binop(fx, *bin_op, lhs, rhs, lval.layout().ty, true)
 448                         }
 449                         _ => unimplemented!("checked binop {:?} for {:?}", bin_op, ty),
 450                     };
 451                     lval.write_cvalue(fx, res);
 452                 }
 453                 Rvalue::UnaryOp(un_op, operand) => {
 454                     let operand = trans_operand(fx, operand);
 455                     let layout = operand.layout();
 456                     let val = operand.load_scalar(fx);
 457                     let res = match un_op {
 458                         UnOp::Not => {
 459                             match layout.ty.sty {
 460                                 ty::Bool => {
 461                                     let val = fx.bcx.ins().uextend(types::I32, val); // WORKAROUND for CraneStation/cranelift#466
 462                                     let res = fx.bcx.ins().icmp_imm(IntCC::Equal, val, 0);
 463                                     fx.bcx.ins().bint(types::I8, res)
 464                                 }
 465                                 ty::Uint(_) | ty::Int(_) => fx.bcx.ins().bnot(val),
 466                                 _ => unimplemented!("un op Not for {:?}", layout.ty),
 467                             }
 468                         }
 469                         UnOp::Neg => match layout.ty.sty {
 470                             ty::Int(_) => {
 471                                 let clif_ty = fx.clif_type(layout.ty).unwrap();
 472                                 let zero = fx.bcx.ins().iconst(clif_ty, 0);
 473                                 fx.bcx.ins().isub(zero, val)
 474                             }
 475                             ty::Float(_) => fx.bcx.ins().fneg(val),
 476                             _ => unimplemented!("un op Neg for {:?}", layout.ty),
 477                         },
 478                     };
 479                     lval.write_cvalue(fx, CValue::ByVal(res, layout));
 480                 }
 481                 Rvalue::Cast(CastKind::Pointer(PointerCast::ReifyFnPointer), operand, ty) => {
 482                     let layout = fx.layout_of(ty);
 483                     match fx
 484                         .monomorphize(&operand.ty(&fx.mir.local_decls, fx.tcx))
 485                         .sty
 486                     {
 487                         ty::FnDef(def_id, substs) => {
 488                             let func_ref = fx.get_function_ref(
 489                                 Instance::resolve(fx.tcx, ParamEnv::reveal_all(), def_id, substs)
 490                                     .unwrap(),
 491                             );
 492                             let func_addr = fx.bcx.ins().func_addr(fx.pointer_type, func_ref);
 493                             lval.write_cvalue(fx, CValue::ByVal(func_addr, layout));
 494                         }
 495                         _ => bug!("Trying to ReifyFnPointer on non FnDef {:?}", ty),
 496                     }
 497                 }
 498                 Rvalue::Cast(CastKind::Pointer(PointerCast::UnsafeFnPointer), operand, ty)
 499                 | Rvalue::Cast(CastKind::Pointer(PointerCast::MutToConstPointer), operand, ty) => {
 500                     let operand = trans_operand(fx, operand);
 501                     let layout = fx.layout_of(ty);
 502                     lval.write_cvalue(fx, operand.unchecked_cast_to(layout));
 503                 }
 504                 Rvalue::Cast(CastKind::Misc, operand, to_ty) => {
 505                     let operand = trans_operand(fx, operand);
 506                     let from_ty = operand.layout().ty;
 507
 508                     fn is_fat_ptr<'a, 'tcx: 'a>(fx: &FunctionCx<'a, 'tcx, impl Backend>, ty: Ty<'tcx>) -> bool {
 509                         ty
 510                             .builtin_deref(true)
 511                             .map(|ty::TypeAndMut {ty: pointee_ty, mutbl: _ }| fx.layout_of(pointee_ty).is_unsized())
 512                             .unwrap_or(false)
 513                     }
 514
 515                     if is_fat_ptr(fx, from_ty) {
 516                         if is_fat_ptr(fx, to_ty) {
 517                             // fat-ptr -> fat-ptr
 518                             lval.write_cvalue(fx, operand.unchecked_cast_to(dest_layout));
 519                         } else {
 520                             // fat-ptr -> thin-ptr
 521                             let (ptr, _extra) = operand.load_scalar_pair(fx);
 522                             lval.write_cvalue(fx, CValue::ByVal(ptr, dest_layout))
 523                         }
 524                     } else if let ty::Adt(adt_def, _substs) = from_ty.sty {
 525                         // enum -> discriminant value
 526                         assert!(adt_def.is_enum());
 527                         match to_ty.sty {
 528                             ty::Uint(_) | ty::Int(_) => {},
 529                             _ => unreachable!("cast adt {} -> {}", from_ty, to_ty),
 530                         }
 531
 532                         // FIXME avoid forcing to stack
 533                         let place =
 534                             CPlace::Addr(operand.force_stack(fx), None, operand.layout());
 535                         let discr = trans_get_discriminant(fx, place, fx.layout_of(to_ty));
 536                         lval.write_cvalue(fx, discr);
 537                     } else {
 538                         let from_clif_ty = fx.clif_type(from_ty).unwrap();
 539                         let to_clif_ty = fx.clif_type(to_ty).unwrap();
 540                         let from = operand.load_scalar(fx);
 541
 542                         let signed = match from_ty.sty {
 543                             ty::Ref(..) | ty::RawPtr(..) | ty::FnPtr(..) | ty::Char | ty::Uint(..) | ty::Bool => false,
 544                             ty::Int(..) => true,
 545                             ty::Float(..) => false, // `signed` is unused for floats
 546                             _ => panic!("{}", from_ty),
 547                         };
 548
 549                         let res = if from_clif_ty.is_int() && to_clif_ty.is_int() {
 550                             // int-like -> int-like
 551                             crate::common::clif_intcast(
 552                                 fx,
 553                                 from,
 554                                 to_clif_ty,
 555                                 signed,
 556                             )
 557                         } else if from_clif_ty.is_int() && to_clif_ty.is_float() {
 558                             // int-like -> float
 559                             // FIXME missing encoding for fcvt_from_sint.f32.i8
 560                             let from = if from_clif_ty == types::I8 || from_clif_ty == types::I16 {
 561                                 fx.bcx.ins().uextend(types::I32, from)
 562                             } else {
 563                                 from
 564                             };
 565                             if signed {
 566                                 fx.bcx.ins().fcvt_from_sint(to_clif_ty, from)
 567                             } else {
 568                                 fx.bcx.ins().fcvt_from_uint(to_clif_ty, from)
 569                             }
 570                         } else if from_clif_ty.is_float() && to_clif_ty.is_int() {
 571                             // float -> int-like
 572                             let from = operand.load_scalar(fx);
 573                             if signed {
 574                                 fx.bcx.ins().fcvt_to_sint_sat(to_clif_ty, from)
 575                             } else {
 576                                 fx.bcx.ins().fcvt_to_uint_sat(to_clif_ty, from)
 577                             }
 578                         } else if from_clif_ty.is_float() && to_clif_ty.is_float() {
 579                             // float -> float
 580                             match (from_clif_ty, to_clif_ty) {
 581                                 (types::F32, types::F64) => {
 582                                     fx.bcx.ins().fpromote(types::F64, from)
 583                                 }
 584                                 (types::F64, types::F32) => {
 585                                     fx.bcx.ins().fdemote(types::F32, from)
 586                                 }
 587                                 _ => from,
 588                             }
 589                         } else {
 590                             unimpl!("rval misc {:?} {:?}", from_ty, to_ty)
 591                         };
 592                         lval.write_cvalue(fx, CValue::ByVal(res, dest_layout));
 593                     }
 594                 }
 595                 Rvalue::Cast(CastKind::Pointer(PointerCast::ClosureFnPointer(_)), operand, _ty) => {
 596                     let operand = trans_operand(fx, operand);
 597                     match operand.layout().ty.sty {
 598                         ty::Closure(def_id, substs) => {
 599                             let instance = rustc_mir::monomorphize::resolve_closure(
 600                                 fx.tcx,
 601                                 def_id,
 602                                 substs,
 603                                 ty::ClosureKind::FnOnce,
 604                             );
 605                             let func_ref = fx.get_function_ref(instance);
 606                             let func_addr = fx.bcx.ins().func_addr(fx.pointer_type, func_ref);
 607                             lval.write_cvalue(fx, CValue::ByVal(func_addr, lval.layout()));
 608                         }
 609                         _ => {
 610                             bug!("{} cannot be cast to a fn ptr", operand.layout().ty)
 611                         }
 612                     }
 613                 }
 614                 Rvalue::Cast(CastKind::Pointer(PointerCast::Unsize), operand, _ty) => {
 615                     let operand = trans_operand(fx, operand);
 616                     operand.unsize_value(fx, lval);
 617                 }
 618                 Rvalue::Discriminant(place) => {
 619                     let place = trans_place(fx, place);
 620                     let discr = trans_get_discriminant(fx, place, dest_layout);
 621                     lval.write_cvalue(fx, discr);
 622                 }
 623                 Rvalue::Repeat(operand, times) => {
 624                     let operand = trans_operand(fx, operand);
 625                     for i in 0..*times {
 626                         let index = fx.bcx.ins().iconst(fx.pointer_type, i as i64);
 627                         let to = lval.place_index(fx, index);
 628                         to.write_cvalue(fx, operand);
 629                     }
 630                 }
 631                 Rvalue::Len(place) => {
 632                     let place = trans_place(fx, place);
 633                     let usize_layout = fx.layout_of(fx.tcx.types.usize);
 634                     let len = codegen_array_len(fx, place);
 635                     lval.write_cvalue(fx, CValue::ByVal(len, usize_layout));
 636                 }
 637                 Rvalue::NullaryOp(NullOp::Box, content_ty) => {
 638                     use rustc::middle::lang_items::ExchangeMallocFnLangItem;
 639
 640                     let usize_type = fx.clif_type(fx.tcx.types.usize).unwrap();
 641                     let layout = fx.layout_of(content_ty);
 642                     let llsize = fx.bcx.ins().iconst(usize_type, layout.size.bytes() as i64);
 643                     let llalign = fx
 644                         .bcx
 645                         .ins()
 646                         .iconst(usize_type, layout.align.abi.bytes() as i64);
 647                     let box_layout = fx.layout_of(fx.tcx.mk_box(content_ty));
 648
 649                     // Allocate space:
 650                     let def_id = match fx.tcx.lang_items().require(ExchangeMallocFnLangItem) {
 651                         Ok(id) => id,
 652                         Err(s) => {
 653                             fx.tcx
 654                                 .sess
 655                                 .fatal(&format!("allocation of `{}` {}", box_layout.ty, s));
 656                         }
 657                     };
 658                     let instance = ty::Instance::mono(fx.tcx, def_id);
 659                     let func_ref = fx.get_function_ref(instance);
 660                     let call = fx.bcx.ins().call(func_ref, &[llsize, llalign]);
 661                     let ptr = fx.bcx.inst_results(call)[0];
 662                     lval.write_cvalue(fx, CValue::ByVal(ptr, box_layout));
 663                 }
 664                 Rvalue::NullaryOp(NullOp::SizeOf, ty) => {
 665                     assert!(lval
 666                         .layout()
 667                         .ty
 668                         .is_sized(fx.tcx.at(DUMMY_SP), ParamEnv::reveal_all()));
 669                     let ty_size = fx.layout_of(ty).size.bytes();
 670                     let val = CValue::const_val(fx, fx.tcx.types.usize, ty_size as i64);
 671                     lval.write_cvalue(fx, val);
 672                 }
 673                 Rvalue::Aggregate(kind, operands) => match **kind {
 674                     AggregateKind::Array(_ty) => {
 675                         for (i, operand) in operands.into_iter().enumerate() {
 676                             let operand = trans_operand(fx, operand);
 677                             let index = fx.bcx.ins().iconst(fx.pointer_type, i as i64);
 678                             let to = lval.place_index(fx, index);
 679                             to.write_cvalue(fx, operand);
 680                         }
 681                     }
 682                     _ => unimpl!("shouldn't exist at trans {:?}", rval),
 683                 },
 684             }
 685         }
 686         StatementKind::StorageLive(_)
 687         | StatementKind::StorageDead(_)
 688         | StatementKind::Nop
 689         | StatementKind::FakeRead(..)
 690         | StatementKind::Retag { .. }
 691         | StatementKind::AscribeUserType(..) => {}
 692
 693         StatementKind::InlineAsm { .. } => unimpl!("Inline assembly is not supported"),
 694     }
 695 }
 696
 697 fn codegen_array_len<'a, 'tcx: 'a>(
 698     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 699     place: CPlace<'tcx>,
 700 ) -> Value {
 701     match place.layout().ty.sty {
 702         ty::Array(_elem_ty, len) => {
 703             let len = crate::constant::force_eval_const(fx, len).unwrap_usize(fx.tcx) as i64;
 704             fx.bcx.ins().iconst(fx.pointer_type, len)
 705         }
 706         ty::Slice(_elem_ty) => place
 707             .to_addr_maybe_unsized(fx)
 708             .1
 709             .expect("Length metadata for slice place"),
 710         _ => bug!("Rvalue::Len({:?})", place),
 711     }
 712 }
 713
 714 pub fn trans_get_discriminant<'a, 'tcx: 'a>(
 715     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 716     place: CPlace<'tcx>,
 717     dest_layout: TyLayout<'tcx>,
 718 ) -> CValue<'tcx> {
 719     let layout = place.layout();
 720
 721     if layout.abi == layout::Abi::Uninhabited {
 722         return trap_unreachable_ret_value(fx, dest_layout, "[panic] Tried to get discriminant for uninhabited type.");
 723     }
 724
 725     let (discr_scalar, discr_index, discr_kind) = match &layout.variants {
 726         layout::Variants::Single { index } => {
 727             let discr_val = layout
 728                 .ty
 729                 .ty_adt_def()
 730                 .map_or(index.as_u32() as u128, |def| {
 731                     def.discriminant_for_variant(fx.tcx, *index).val
 732                 });
 733             return CValue::const_val(fx, dest_layout.ty, discr_val as u64 as i64);
 734         }
 735         layout::Variants::Multiple { discr, discr_index, discr_kind, variants: _ } => {
 736             (discr, *discr_index, discr_kind)
 737         }
 738     };
 739
 740     let discr = place.place_field(fx, mir::Field::new(discr_index)).to_cvalue(fx);
 741     let discr_ty = discr.layout().ty;
 742     let lldiscr = discr.load_scalar(fx);
 743     match discr_kind {
 744         layout::DiscriminantKind::Tag => {
 745             let signed = match discr_scalar.value {
 746                 layout::Int(_, signed) => signed,
 747                 _ => false,
 748             };
 749             let val = clif_intcast(fx, lldiscr, fx.clif_type(dest_layout.ty).unwrap(), signed);
 750             return CValue::ByVal(val, dest_layout);
 751         }
 752         layout::DiscriminantKind::Niche {
 753             dataful_variant,
 754             ref niche_variants,
 755             niche_start,
 756         } => {
 757             let niche_llty = fx.clif_type(discr_ty).unwrap();
 758             let dest_clif_ty = fx.clif_type(dest_layout.ty).unwrap();
 759             if niche_variants.start() == niche_variants.end() {
 760                 let b = fx
 761                     .bcx
 762                     .ins()
 763                     .icmp_imm(IntCC::Equal, lldiscr, *niche_start as u64 as i64);
 764                 let if_true = fx
 765                     .bcx
 766                     .ins()
 767                     .iconst(dest_clif_ty, niche_variants.start().as_u32() as i64);
 768                 let if_false = fx
 769                     .bcx
 770                     .ins()
 771                     .iconst(dest_clif_ty, dataful_variant.as_u32() as i64);
 772                 let val = fx.bcx.ins().select(b, if_true, if_false);
 773                 return CValue::ByVal(val, dest_layout);
 774             } else {
 775                 // Rebase from niche values to discriminant values.
 776                 let delta = niche_start.wrapping_sub(niche_variants.start().as_u32() as u128);
 777                 let delta = fx.bcx.ins().iconst(niche_llty, delta as u64 as i64);
 778                 let lldiscr = fx.bcx.ins().isub(lldiscr, delta);
 779                 let b = fx.bcx.ins().icmp_imm(
 780                     IntCC::UnsignedLessThanOrEqual,
 781                     lldiscr,
 782                     niche_variants.end().as_u32() as i64,
 783                 );
 784                 let if_true =
 785                     clif_intcast(fx, lldiscr, fx.clif_type(dest_layout.ty).unwrap(), false);
 786                 let if_false = fx
 787                     .bcx
 788                     .ins()
 789                     .iconst(dest_clif_ty, dataful_variant.as_u32() as i64);
 790                 let val = fx.bcx.ins().select(b, if_true, if_false);
 791                 return CValue::ByVal(val, dest_layout);
 792             }
 793         }
 794     }
 795 }
 796
 797 macro_rules! binop_match {
 798     (@single $fx:expr, $bug_fmt:expr, $var:expr, $signed:expr, $lhs:expr, $rhs:expr, $ret_ty:expr, bug) => {
 799         bug!("binop {} on {} lhs: {:?} rhs: {:?}", stringify!($var), $bug_fmt, $lhs, $rhs)
 800     };
 801     (@single $fx:expr, $bug_fmt:expr, $var:expr, $signed:expr, $lhs:expr, $rhs:expr, $ret_ty:expr, icmp($cc:ident)) => {{
 802         assert_eq!($fx.tcx.types.bool, $ret_ty);
 803         let ret_layout = $fx.layout_of($ret_ty);
 804
 805         let b = $fx.bcx.ins().icmp(IntCC::$cc, $lhs, $rhs);
 806         CValue::ByVal($fx.bcx.ins().bint(types::I8, b), ret_layout)
 807     }};
 808     (@single $fx:expr, $bug_fmt:expr, $var:expr, $signed:expr, $lhs:expr, $rhs:expr, $ret_ty:expr, fcmp($cc:ident)) => {{
 809         assert_eq!($fx.tcx.types.bool, $ret_ty);
 810         let ret_layout = $fx.layout_of($ret_ty);
 811         let b = $fx.bcx.ins().fcmp(FloatCC::$cc, $lhs, $rhs);
 812         CValue::ByVal($fx.bcx.ins().bint(types::I8, b), ret_layout)
 813     }};
 814     (@single $fx:expr, $bug_fmt:expr, $var:expr, $signed:expr, $lhs:expr, $rhs:expr, $ret_ty:expr, custom(|| $body:expr)) => {{
 815         $body
 816     }};
 817     (@single $fx:expr, $bug_fmt:expr, $var:expr, $signed:expr, $lhs:expr, $rhs:expr, $ret_ty:expr, $name:ident) => {{
 818         let ret_layout = $fx.layout_of($ret_ty);
 819         CValue::ByVal($fx.bcx.ins().$name($lhs, $rhs), ret_layout)
 820     }};
 821     (
 822         $fx:expr, $bin_op:expr, $signed:expr, $lhs:expr, $rhs:expr, $ret_ty:expr, $bug_fmt:expr;
 823         $(
 824             $var:ident ($sign:pat) $name:tt $( ( $($next:tt)* ) )? ;
 825         )*
 826     ) => {{
 827         let lhs = $lhs.load_scalar($fx);
 828         let rhs = $rhs.load_scalar($fx);
 829         match ($bin_op, $signed) {
 830             $(
 831                 (BinOp::$var, $sign) => binop_match!(@single $fx, $bug_fmt, $var, $signed, lhs, rhs, $ret_ty, $name $( ( $($next)* ) )?),
 832             )*
 833         }
 834     }}
 835 }
 836
 837 fn trans_bool_binop<'a, 'tcx: 'a>(
 838     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 839     bin_op: BinOp,
 840     lhs: CValue<'tcx>,
 841     rhs: CValue<'tcx>,
 842     ty: Ty<'tcx>,
 843 ) -> CValue<'tcx> {
 844     let res = binop_match! {
 845         fx, bin_op, false, lhs, rhs, ty, "bool";
 846         Add (_) bug;
 847         Sub (_) bug;
 848         Mul (_) bug;
 849         Div (_) bug;
 850         Rem (_) bug;
 851         BitXor (_) bxor;
 852         BitAnd (_) band;
 853         BitOr (_) bor;
 854         Shl (_) bug;
 855         Shr (_) bug;
 856
 857         Eq (_) icmp(Equal);
 858         Lt (_) icmp(UnsignedLessThan);
 859         Le (_) icmp(UnsignedLessThanOrEqual);
 860         Ne (_) icmp(NotEqual);
 861         Ge (_) icmp(UnsignedGreaterThanOrEqual);
 862         Gt (_) icmp(UnsignedGreaterThan);
 863
 864         Offset (_) bug;
 865     };
 866
 867     res
 868 }
 869
 870 pub fn trans_int_binop<'a, 'tcx: 'a>(
 871     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 872     bin_op: BinOp,
 873     lhs: CValue<'tcx>,
 874     rhs: CValue<'tcx>,
 875     out_ty: Ty<'tcx>,
 876     signed: bool,
 877 ) -> CValue<'tcx> {
 878     if bin_op != BinOp::Shl && bin_op != BinOp::Shr {
 879         assert_eq!(
 880             lhs.layout().ty,
 881             rhs.layout().ty,
 882             "int binop requires lhs and rhs of same type"
 883         );
 884     }
 885     binop_match! {
 886         fx, bin_op, signed, lhs, rhs, out_ty, "int/uint";
 887         Add (_) iadd;
 888         Sub (_) isub;
 889         Mul (_) imul;
 890         Div (false) udiv;
 891         Div (true) sdiv;
 892         Rem (false) urem;
 893         Rem (true) srem;
 894         BitXor (_) bxor;
 895         BitAnd (_) band;
 896         BitOr (_) bor;
 897         Shl (_) ishl;
 898         Shr (false) ushr;
 899         Shr (true) sshr;
 900
 901         Eq (_) icmp(Equal);
 902         Lt (false) icmp(UnsignedLessThan);
 903         Lt (true) icmp(SignedLessThan);
 904         Le (false) icmp(UnsignedLessThanOrEqual);
 905         Le (true) icmp(SignedLessThanOrEqual);
 906         Ne (_) icmp(NotEqual);
 907         Ge (false) icmp(UnsignedGreaterThanOrEqual);
 908         Ge (true) icmp(SignedGreaterThanOrEqual);
 909         Gt (false) icmp(UnsignedGreaterThan);
 910         Gt (true) icmp(SignedGreaterThan);
 911
 912         Offset (_) bug;
 913     }
 914 }
 915
 916 pub fn trans_checked_int_binop<'a, 'tcx: 'a>(
 917     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 918     bin_op: BinOp,
 919     in_lhs: CValue<'tcx>,
 920     in_rhs: CValue<'tcx>,
 921     out_ty: Ty<'tcx>,
 922     signed: bool,
 923 ) -> CValue<'tcx> {
 924     if bin_op != BinOp::Shl && bin_op != BinOp::Shr {
 925         assert_eq!(
 926             in_lhs.layout().ty,
 927             in_rhs.layout().ty,
 928             "checked int binop requires lhs and rhs of same type"
 929         );
 930     }
 931
 932     let lhs = in_lhs.load_scalar(fx);
 933     let rhs = in_rhs.load_scalar(fx);
 934     let res = match bin_op {
 935         BinOp::Add => fx.bcx.ins().iadd(lhs, rhs),
 936         BinOp::Sub => fx.bcx.ins().isub(lhs, rhs),
 937         BinOp::Mul => fx.bcx.ins().imul(lhs, rhs),
 938         BinOp::Shl => fx.bcx.ins().ishl(lhs, rhs),
 939         BinOp::Shr => {
 940             if !signed {
 941                 fx.bcx.ins().ushr(lhs, rhs)
 942             } else {
 943                 fx.bcx.ins().sshr(lhs, rhs)
 944             }
 945         }
 946         _ => bug!(
 947             "binop {:?} on checked int/uint lhs: {:?} rhs: {:?}",
 948             bin_op,
 949             in_lhs,
 950             in_rhs
 951         ),
 952     };
 953
 954     // TODO: check for overflow
 955     let has_overflow = fx.bcx.ins().iconst(types::I8, 0);
 956
 957     let out_place = CPlace::new_stack_slot(fx, out_ty);
 958     let out_layout = out_place.layout();
 959     out_place.write_cvalue(fx, CValue::ByValPair(res, has_overflow, out_layout));
 960
 961     out_place.to_cvalue(fx)
 962 }
 963
 964 fn trans_float_binop<'a, 'tcx: 'a>(
 965     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 966     bin_op: BinOp,
 967     lhs: CValue<'tcx>,
 968     rhs: CValue<'tcx>,
 969     ty: Ty<'tcx>,
 970 ) -> CValue<'tcx> {
 971     let res = binop_match! {
 972         fx, bin_op, false, lhs, rhs, ty, "float";
 973         Add (_) fadd;
 974         Sub (_) fsub;
 975         Mul (_) fmul;
 976         Div (_) fdiv;
 977         Rem (_) custom(|| {
 978             assert_eq!(lhs.layout().ty, ty);
 979             assert_eq!(rhs.layout().ty, ty);
 980             match ty.sty {
 981                 ty::Float(FloatTy::F32) => fx.easy_call("fmodf", &[lhs, rhs], ty),
 982                 ty::Float(FloatTy::F64) => fx.easy_call("fmod", &[lhs, rhs], ty),
 983                 _ => bug!(),
 984             }
 985         });
 986         BitXor (_) bxor;
 987         BitAnd (_) band;
 988         BitOr (_) bor;
 989         Shl (_) bug;
 990         Shr (_) bug;
 991
 992         Eq (_) fcmp(Equal);
 993         Lt (_) fcmp(LessThan);
 994         Le (_) fcmp(LessThanOrEqual);
 995         Ne (_) fcmp(NotEqual);
 996         Ge (_) fcmp(GreaterThanOrEqual);
 997         Gt (_) fcmp(GreaterThan);
 998
 999         Offset (_) bug;
1000     };
1001
1002     res
1003 }
1004
1005 fn trans_char_binop<'a, 'tcx: 'a>(
1006     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
1007     bin_op: BinOp,
1008     lhs: CValue<'tcx>,
1009     rhs: CValue<'tcx>,
1010     ty: Ty<'tcx>,
1011 ) -> CValue<'tcx> {
1012     let res = binop_match! {
1013         fx, bin_op, false, lhs, rhs, ty, "char";
1014         Add (_) bug;
1015         Sub (_) bug;
1016         Mul (_) bug;
1017         Div (_) bug;
1018         Rem (_) bug;
1019         BitXor (_) bug;
1020         BitAnd (_) bug;
1021         BitOr (_) bug;
1022         Shl (_) bug;
1023         Shr (_) bug;
1024
1025         Eq (_) icmp(Equal);
1026         Lt (_) icmp(UnsignedLessThan);
1027         Le (_) icmp(UnsignedLessThanOrEqual);
1028         Ne (_) icmp(NotEqual);
1029         Ge (_) icmp(UnsignedGreaterThanOrEqual);
1030         Gt (_) icmp(UnsignedGreaterThan);
1031
1032         Offset (_) bug;
1033     };
1034
1035     res
1036 }
1037
1038 fn trans_ptr_binop<'a, 'tcx: 'a>(
1039     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
1040     bin_op: BinOp,
1041     lhs: CValue<'tcx>,
1042     rhs: CValue<'tcx>,
1043     ret_ty: Ty<'tcx>,
1044 ) -> CValue<'tcx> {
1045     let not_fat = match lhs.layout().ty.sty {
1046         ty::RawPtr(TypeAndMut { ty, mutbl: _ }) => {
1047             ty.is_sized(fx.tcx.at(DUMMY_SP), ParamEnv::reveal_all())
1048         }
1049         ty::FnPtr(..) => true,
1050         _ => bug!("trans_ptr_binop on non ptr"),
1051     };
1052     if not_fat {
1053         if let BinOp::Offset = bin_op {
1054             let (base, offset) = (lhs, rhs.load_scalar(fx));
1055             let pointee_ty = base.layout().ty.builtin_deref(true).unwrap().ty;
1056             let pointee_size = fx.layout_of(pointee_ty).size.bytes();
1057             let ptr_diff = fx.bcx.ins().imul_imm(offset, pointee_size as i64);
1058             let base_val = base.load_scalar(fx);
1059             let res = fx.bcx.ins().iadd(base_val, ptr_diff);
1060             return CValue::ByVal(res, base.layout());
1061         }
1062
1063         binop_match! {
1064             fx, bin_op, false, lhs, rhs, ret_ty, "ptr";
1065             Add (_) bug;
1066             Sub (_) bug;
1067             Mul (_) bug;
1068             Div (_) bug;
1069             Rem (_) bug;
1070             BitXor (_) bug;
1071             BitAnd (_) bug;
1072             BitOr (_) bug;
1073             Shl (_) bug;
1074             Shr (_) bug;
1075
1076             Eq (_) icmp(Equal);
1077             Lt (_) icmp(UnsignedLessThan);
1078             Le (_) icmp(UnsignedLessThanOrEqual);
1079             Ne (_) icmp(NotEqual);
1080             Ge (_) icmp(UnsignedGreaterThanOrEqual);
1081             Gt (_) icmp(UnsignedGreaterThan);
1082
1083             Offset (_) bug; // Handled above
1084         }
1085     } else {
1086         let (lhs_ptr, lhs_extra) = lhs.load_scalar_pair(fx);
1087         let (rhs_ptr, rhs_extra) = rhs.load_scalar_pair(fx);
1088         let res = match bin_op {
1089             BinOp::Eq => {
1090                 let ptr_eq = fx.bcx.ins().icmp(IntCC::Equal, lhs_ptr, rhs_ptr);
1091                 let extra_eq = fx.bcx.ins().icmp(IntCC::Equal, lhs_extra, rhs_extra);
1092                 fx.bcx.ins().band(ptr_eq, extra_eq)
1093             }
1094             BinOp::Ne => {
1095                 let ptr_ne = fx.bcx.ins().icmp(IntCC::NotEqual, lhs_ptr, rhs_ptr);
1096                 let extra_ne = fx.bcx.ins().icmp(IntCC::NotEqual, lhs_extra, rhs_extra);
1097                 fx.bcx.ins().bor(ptr_ne, extra_ne)
1098             }
1099             _ => unimplemented!(
1100                 "trans_ptr_binop({:?}, <fat ptr>, <fat ptr>) not implemented",
1101                 bin_op
1102             ),
1103         };
1104
1105         assert_eq!(fx.tcx.types.bool, ret_ty);
1106         let ret_layout = fx.layout_of(ret_ty);
1107         CValue::ByVal(fx.bcx.ins().bint(types::I8, res), ret_layout)
1108     }
1109 }
1110
1111 pub fn trans_place<'a, 'tcx: 'a>(
1112     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
1113     place: &Place<'tcx>,
1114 ) -> CPlace<'tcx> {
1115     match place {
1116         Place::Base(base) => match base {
1117             PlaceBase::Local(local) => fx.get_local_place(*local),
1118             PlaceBase::Static(static_) => match static_.kind {
1119                 StaticKind::Static(def_id) => {
1120                     crate::constant::codegen_static_ref(fx, def_id, static_.ty)
1121                 }
1122                 StaticKind::Promoted(promoted) => {
1123                     crate::constant::trans_promoted(fx, promoted, static_.ty)
1124                 }
1125             }
1126         }
1127         Place::Projection(projection) => {
1128             let base = trans_place(fx, &projection.base);
1129             match projection.elem {
1130                 ProjectionElem::Deref => base.place_deref(fx),
1131                 ProjectionElem::Field(field, _ty) => base.place_field(fx, field),
1132                 ProjectionElem::Index(local) => {
1133                     let index = fx.get_local_place(local).to_cvalue(fx).load_scalar(fx);
1134                     base.place_index(fx, index)
1135                 }
1136                 ProjectionElem::ConstantIndex {
1137                     offset,
1138                     min_length: _,
1139                     from_end,
1140                 } => {
1141                     let index = if !from_end {
1142                         fx.bcx.ins().iconst(fx.pointer_type, offset as i64)
1143                     } else {
1144                         let len = codegen_array_len(fx, base);
1145                         fx.bcx.ins().iadd_imm(len, -(offset as i64))
1146                     };
1147                     base.place_index(fx, index)
1148                 }
1149                 ProjectionElem::Subslice { from, to } => {
1150                     // These indices are generated by slice patterns.
1151                     // slice[from:-to] in Python terms.
1152
1153                     match base.layout().ty.sty {
1154                         ty::Array(elem_ty, len) => {
1155                             let elem_layout = fx.layout_of(elem_ty);
1156                             let ptr = base.to_addr(fx);
1157                             let len = crate::constant::force_eval_const(fx, len).unwrap_usize(fx.tcx);
1158                             CPlace::Addr(
1159                                 fx.bcx.ins().iadd_imm(ptr, elem_layout.size.bytes() as i64 * from as i64),
1160                                 None,
1161                                 fx.layout_of(fx.tcx.mk_array(elem_ty, len - from as u64 - to as u64)),
1162                             )
1163                         }
1164                         ty::Slice(elem_ty) => {
1165                             let elem_layout = fx.layout_of(elem_ty);
1166                             let (ptr, len) = base.to_addr_maybe_unsized(fx);
1167                             let len = len.unwrap();
1168                             CPlace::Addr(
1169                                 fx.bcx.ins().iadd_imm(ptr, elem_layout.size.bytes() as i64 * from as i64),
1170                                 Some(fx.bcx.ins().iadd_imm(len, -(from as i64 + to as i64))),
1171                                 base.layout(),
1172                             )
1173                         }
1174                         _ => unreachable!(),
1175                     }
1176                 }
1177                 ProjectionElem::Downcast(_adt_def, variant) => base.downcast_variant(fx, variant),
1178             }
1179         }
1180     }
1181 }
1182
1183 pub fn trans_operand<'a, 'tcx>(
1184     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
1185     operand: &Operand<'tcx>,
1186 ) -> CValue<'tcx> {
1187     match operand {
1188         Operand::Move(place) | Operand::Copy(place) => {
1189             let cplace = trans_place(fx, place);
1190             cplace.to_cvalue(fx)
1191         }
1192         Operand::Constant(const_) => crate::constant::trans_constant(fx, const_),
1193     }
1194 }