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     let mir = tcx.instance_mir(instance.def);
  13
  14     // Check fn sig for u128 and i128 and replace those functions with a trap.
  15     {
  16         // FIXME implement u128 and i128 support
  17
  18         // Check sig for u128 and i128
  19         let fn_sig = tcx.normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), &instance.fn_sig(tcx));
  20
  21         struct UI128Visitor<'a, 'tcx: 'a>(TyCtxt<'a, 'tcx, 'tcx>, bool);
  22
  23         impl<'a, 'tcx: 'a> rustc::ty::fold::TypeVisitor<'tcx> for UI128Visitor<'a, 'tcx> {
  24             fn visit_ty(&mut self, t: Ty<'tcx>) -> bool {
  25                 if t.sty == self.0.types.u128.sty || t.sty == self.0.types.i128.sty {
  26                     self.1 = true;
  27                     return false; // stop visiting
  28                 }
  29
  30                 t.super_visit_with(self)
  31             }
  32         }
  33
  34         let mut visitor = UI128Visitor(tcx, false);
  35         fn_sig.visit_with(&mut visitor);
  36
  37         //If found replace function with a trap.
  38         if visitor.1 {
  39             tcx.sess.warn("u128 and i128 are not yet supported. \
  40             Functions using these as args will be replaced with a trap.");
  41
  42             // Declare function with fake signature
  43             let sig = Signature {
  44                 params: vec![AbiParam::new(types::INVALID)],
  45                 returns: vec![],
  46                 call_conv: CallConv::Fast,
  47             };
  48             let name = tcx.symbol_name(instance).as_str();
  49             let func_id = cx.module.declare_function(&*name, linkage, &sig).unwrap();
  50
  51             // Create trapping function
  52             let mut func = Function::with_name_signature(ExternalName::user(0, 0), sig);
  53             let mut func_ctx = FunctionBuilderContext::new();
  54             let mut bcx = FunctionBuilder::new(&mut func, &mut func_ctx);
  55             let start_ebb = bcx.create_ebb();
  56             bcx.append_ebb_params_for_function_params(start_ebb);
  57             bcx.switch_to_block(start_ebb);
  58
  59             let mut fx = FunctionCx {
  60                 tcx,
  61                 module: cx.module,
  62                 pointer_type: pointer_ty(tcx),
  63
  64                 instance,
  65                 mir,
  66
  67                 bcx,
  68                 ebb_map: HashMap::new(),
  69                 local_map: HashMap::new(),
  70
  71                 clif_comments: crate::pretty_clif::CommentWriter::new(tcx, instance),
  72                 constants: &mut cx.ccx,
  73                 caches: &mut cx.caches,
  74                 source_info_set: indexmap::IndexSet::new(),
  75             };
  76
  77             crate::trap::trap_unreachable(&mut fx, "[unimplemented] Called function with u128 or i128 as argument.");
  78             fx.bcx.seal_all_blocks();
  79             fx.bcx.finalize();
  80
  81             // Define function
  82             cx.caches.context.func = func;
  83             cx.module
  84                 .define_function(func_id, &mut cx.caches.context)
  85                 .unwrap();
  86             cx.caches.context.clear();
  87             return;
  88         }
  89     }
  90
  91     // Declare function
  92     let (name, sig) = get_function_name_and_sig(tcx, instance, false);
  93     let func_id = cx.module.declare_function(&name, linkage, &sig).unwrap();
  94     let mut debug_context = cx
  95         .debug_context
  96         .as_mut()
  97         .map(|debug_context| FunctionDebugContext::new(tcx, debug_context, mir, &name, &sig));
  98
  99     // Make FunctionBuilder
 100     let mut func = Function::with_name_signature(ExternalName::user(0, 0), sig);
 101     let mut func_ctx = FunctionBuilderContext::new();
 102     let mut bcx = FunctionBuilder::new(&mut func, &mut func_ctx);
 103
 104     // Predefine ebb's
 105     let start_ebb = bcx.create_ebb();
 106     let mut ebb_map: HashMap<BasicBlock, Ebb> = HashMap::new();
 107     for (bb, _bb_data) in mir.basic_blocks().iter_enumerated() {
 108         ebb_map.insert(bb, bcx.create_ebb());
 109     }
 110
 111     // Make FunctionCx
 112     let pointer_type = cx.module.target_config().pointer_type();
 113     let clif_comments = crate::pretty_clif::CommentWriter::new(tcx, instance);
 114
 115     let mut fx = FunctionCx {
 116         tcx,
 117         module: cx.module,
 118         pointer_type,
 119
 120         instance,
 121         mir,
 122
 123         bcx,
 124         ebb_map,
 125         local_map: HashMap::new(),
 126
 127         clif_comments,
 128         constants: &mut cx.ccx,
 129         caches: &mut cx.caches,
 130         source_info_set: indexmap::IndexSet::new(),
 131     };
 132
 133     with_unimpl_span(fx.mir.span, || {
 134         crate::abi::codegen_fn_prelude(&mut fx, start_ebb);
 135         codegen_fn_content(&mut fx);
 136     });
 137
 138     // Recover all necessary data from fx, before accessing func will prevent future access to it.
 139     let instance = fx.instance;
 140     let clif_comments = fx.clif_comments;
 141     let source_info_set = fx.source_info_set;
 142
 143     #[cfg(debug_assertions)]
 144     crate::pretty_clif::write_clif_file(cx.tcx, "unopt", instance, &func, &clif_comments, None);
 145
 146     // Verify function
 147     verify_func(tcx, &clif_comments, &func);
 148
 149     // Define function
 150     let context = &mut cx.caches.context;
 151     context.func = func;
 152     cx.module
 153         .define_function(func_id, context)
 154         .unwrap();
 155
 156     let value_ranges = context.build_value_labels_ranges(cx.module.isa()).expect("value location ranges");
 157
 158     // Write optimized function to file for debugging
 159     #[cfg(debug_assertions)]
 160     crate::pretty_clif::write_clif_file(cx.tcx, "opt", instance, &context.func, &clif_comments, Some(&value_ranges));
 161
 162     // Define debuginfo for function
 163     let isa = cx.module.isa();
 164     debug_context
 165         .as_mut()
 166         .map(|x| x.define(tcx, context, isa, &source_info_set));
 167
 168     // Clear context to make it usable for the next function
 169     context.clear();
 170 }
 171
 172 fn verify_func(tcx: TyCtxt, writer: &crate::pretty_clif::CommentWriter, func: &Function) {
 173     let flags = settings::Flags::new(settings::builder());
 174     match ::cranelift::codegen::verify_function(&func, &flags) {
 175         Ok(_) => {}
 176         Err(err) => {
 177             tcx.sess.err(&format!("{:?}", err));
 178             let pretty_error = ::cranelift::codegen::print_errors::pretty_verifier_error(
 179                 &func,
 180                 None,
 181                 Some(Box::new(writer)),
 182                 err,
 183             );
 184             tcx.sess
 185                 .fatal(&format!("cranelift verify error:\n{}", pretty_error));
 186         }
 187     }
 188 }
 189
 190 fn codegen_fn_content<'a, 'tcx: 'a>(fx: &mut FunctionCx<'a, 'tcx, impl Backend>) {
 191     for (bb, bb_data) in fx.mir.basic_blocks().iter_enumerated() {
 192         if bb_data.is_cleanup {
 193             // Unwinding after panicking is not supported
 194             continue;
 195         }
 196
 197         let ebb = fx.get_ebb(bb);
 198         fx.bcx.switch_to_block(ebb);
 199
 200         fx.bcx.ins().nop();
 201         for stmt in &bb_data.statements {
 202             fx.set_debug_loc(stmt.source_info);
 203             trans_stmt(fx, ebb, stmt);
 204         }
 205
 206         #[cfg(debug_assertions)]
 207         {
 208             let mut terminator_head = "\n".to_string();
 209             bb_data
 210                 .terminator()
 211                 .kind
 212                 .fmt_head(&mut terminator_head)
 213                 .unwrap();
 214             let inst = fx.bcx.func.layout.last_inst(ebb).unwrap();
 215             fx.add_comment(inst, terminator_head);
 216         }
 217
 218         fx.set_debug_loc(bb_data.terminator().source_info);
 219
 220         match &bb_data.terminator().kind {
 221             TerminatorKind::Goto { target } => {
 222                 let ebb = fx.get_ebb(*target);
 223                 fx.bcx.ins().jump(ebb, &[]);
 224             }
 225             TerminatorKind::Return => {
 226                 crate::abi::codegen_return(fx);
 227             }
 228             TerminatorKind::Assert {
 229                 cond,
 230                 expected,
 231                 msg,
 232                 target,
 233                 cleanup: _,
 234             } => {
 235                 let cond = trans_operand(fx, cond).load_scalar(fx);
 236                 // TODO HACK brz/brnz for i8/i16 is not yet implemented
 237                 let cond = fx.bcx.ins().uextend(types::I32, cond);
 238                 let target = fx.get_ebb(*target);
 239                 if *expected {
 240                     fx.bcx.ins().brnz(cond, target, &[]);
 241                 } else {
 242                     fx.bcx.ins().brz(cond, target, &[]);
 243                 };
 244                 trap_panic(fx, format!("[panic] Assert {:?} failed.", msg));
 245             }
 246
 247             TerminatorKind::SwitchInt {
 248                 discr,
 249                 switch_ty: _,
 250                 values,
 251                 targets,
 252             } => {
 253                 let discr = trans_operand(fx, discr).load_scalar(fx);
 254                 let mut switch = ::cranelift::frontend::Switch::new();
 255                 for (i, value) in values.iter().enumerate() {
 256                     let ebb = fx.get_ebb(targets[i]);
 257                     switch.set_entry(*value as u64, ebb);
 258                 }
 259                 let otherwise_ebb = fx.get_ebb(targets[targets.len() - 1]);
 260                 switch.emit(&mut fx.bcx, discr, otherwise_ebb);
 261             }
 262             TerminatorKind::Call {
 263                 func,
 264                 args,
 265                 destination,
 266                 cleanup: _,
 267                 from_hir_call: _,
 268             } => {
 269                 crate::abi::codegen_terminator_call(fx, func, args, destination);
 270             }
 271             TerminatorKind::Resume | TerminatorKind::Abort => {
 272                 trap_unreachable(fx, "[corruption] Unwinding bb reached.");
 273             }
 274             TerminatorKind::Unreachable => {
 275                 trap_unreachable(fx, "[corruption] Hit unreachable code.");
 276             }
 277             TerminatorKind::Yield { .. }
 278             | TerminatorKind::FalseEdges { .. }
 279             | TerminatorKind::FalseUnwind { .. }
 280             | TerminatorKind::DropAndReplace { .. }
 281             | TerminatorKind::GeneratorDrop => {
 282                 bug!("shouldn't exist at trans {:?}", bb_data.terminator());
 283             }
 284             TerminatorKind::Drop {
 285                 location,
 286                 target,
 287                 unwind: _,
 288             } => {
 289                 let ty = location.ty(fx.mir, fx.tcx).ty;
 290                 let ty = fx.monomorphize(&ty);
 291                 let drop_fn = Instance::resolve_drop_in_place(fx.tcx, ty);
 292
 293                 if let ty::InstanceDef::DropGlue(_, None) = drop_fn.def {
 294                     // we don't actually need to drop anything
 295                 } else {
 296                     let drop_place = trans_place(fx, location);
 297                     let drop_fn_ty = drop_fn.ty(fx.tcx);
 298                     match ty.sty {
 299                         ty::Dynamic(..) => {
 300                             crate::abi::codegen_drop(fx, drop_place, drop_fn_ty);
 301                         }
 302                         _ => {
 303                             let arg_place = CPlace::new_stack_slot(
 304                                 fx,
 305                                 fx.tcx.mk_ref(
 306                                     &ty::RegionKind::ReErased,
 307                                     TypeAndMut {
 308                                         ty,
 309                                         mutbl: crate::rustc::hir::Mutability::MutMutable,
 310                                     },
 311                                 ),
 312                             );
 313                             drop_place.write_place_ref(fx, arg_place);
 314                             let arg_value = arg_place.to_cvalue(fx);
 315                             crate::abi::codegen_call_inner(
 316                                 fx,
 317                                 None,
 318                                 drop_fn_ty,
 319                                 vec![arg_value],
 320                                 None,
 321                             );
 322                         }
 323                     }
 324                 }
 325
 326                 let target_ebb = fx.get_ebb(*target);
 327                 fx.bcx.ins().jump(target_ebb, &[]);
 328             }
 329         };
 330     }
 331
 332     fx.bcx.seal_all_blocks();
 333     fx.bcx.finalize();
 334 }
 335
 336 fn trans_stmt<'a, 'tcx: 'a>(
 337     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 338     cur_ebb: Ebb,
 339     stmt: &Statement<'tcx>,
 340 ) {
 341     let _print_guard = PrintOnPanic(|| format!("stmt {:?}", stmt));
 342
 343     fx.set_debug_loc(stmt.source_info);
 344
 345     #[cfg(debug_assertions)]
 346     match &stmt.kind {
 347         StatementKind::StorageLive(..) | StatementKind::StorageDead(..) => {} // Those are not very useful
 348         _ => {
 349             let inst = fx.bcx.func.layout.last_inst(cur_ebb).unwrap();
 350             fx.add_comment(inst, format!("{:?}", stmt));
 351         }
 352     }
 353
 354     match &stmt.kind {
 355         StatementKind::SetDiscriminant {
 356             place,
 357             variant_index,
 358         } => {
 359             let place = trans_place(fx, place);
 360             let layout = place.layout();
 361             if layout.for_variant(&*fx, *variant_index).abi == layout::Abi::Uninhabited {
 362                 return;
 363             }
 364             match layout.variants {
 365                 layout::Variants::Single { index } => {
 366                     assert_eq!(index, *variant_index);
 367                 }
 368                 layout::Variants::Multiple {
 369                     discr: _,
 370                     discr_index,
 371                     discr_kind: layout::DiscriminantKind::Tag,
 372                     variants: _,
 373                 } => {
 374                     let ptr = place.place_field(fx, mir::Field::new(discr_index));
 375                     let to = layout
 376                         .ty
 377                         .ty_adt_def()
 378                         .unwrap()
 379                         .discriminant_for_variant(fx.tcx, *variant_index)
 380                         .val;
 381                     let discr = CValue::const_val(fx, ptr.layout().ty, to as u64 as i64);
 382                     ptr.write_cvalue(fx, discr);
 383                 }
 384                 layout::Variants::Multiple {
 385                     discr: _,
 386                     discr_index,
 387                     discr_kind: layout::DiscriminantKind::Niche {
 388                         dataful_variant,
 389                         ref niche_variants,
 390                         niche_start,
 391                     },
 392                     variants: _,
 393                 } => {
 394                     if *variant_index != dataful_variant {
 395                         let niche = place.place_field(fx, mir::Field::new(discr_index));
 396                         //let niche_llty = niche.layout.immediate_llvm_type(bx.cx);
 397                         let niche_value =
 398                             ((variant_index.as_u32() - niche_variants.start().as_u32()) as u128)
 399                                 .wrapping_add(niche_start);
 400                         // FIXME(eddyb) Check the actual primitive type here.
 401                         let niche_llval = if niche_value == 0 {
 402                             CValue::const_val(fx, niche.layout().ty, 0)
 403                         } else {
 404                             CValue::const_val(fx, niche.layout().ty, niche_value as u64 as i64)
 405                         };
 406                         niche.write_cvalue(fx, niche_llval);
 407                     }
 408                 }
 409             }
 410         }
 411         StatementKind::Assign(to_place, rval) => {
 412             let lval = trans_place(fx, to_place);
 413             let dest_layout = lval.layout();
 414             match &**rval {
 415                 Rvalue::Use(operand) => {
 416                     let val = trans_operand(fx, operand);
 417                     lval.write_cvalue(fx, val);
 418                 }
 419                 Rvalue::Ref(_, _, place) => {
 420                     let place = trans_place(fx, place);
 421                     place.write_place_ref(fx, lval);
 422                 }
 423                 Rvalue::BinaryOp(bin_op, lhs, rhs) => {
 424                     let ty = fx.monomorphize(&lhs.ty(fx.mir, fx.tcx));
 425                     let lhs = trans_operand(fx, lhs);
 426                     let rhs = trans_operand(fx, rhs);
 427
 428                     let res = match ty.sty {
 429                         ty::Bool => trans_bool_binop(fx, *bin_op, lhs, rhs, lval.layout().ty),
 430                         ty::Uint(_) => {
 431                             trans_int_binop(fx, *bin_op, lhs, rhs, lval.layout().ty, false)
 432                         }
 433                         ty::Int(_) => {
 434                             trans_int_binop(fx, *bin_op, lhs, rhs, lval.layout().ty, true)
 435                         }
 436                         ty::Float(_) => trans_float_binop(fx, *bin_op, lhs, rhs, lval.layout().ty),
 437                         ty::Char => trans_char_binop(fx, *bin_op, lhs, rhs, lval.layout().ty),
 438                         ty::RawPtr(..) => trans_ptr_binop(fx, *bin_op, lhs, rhs, lval.layout().ty),
 439                         ty::FnPtr(..) => trans_ptr_binop(fx, *bin_op, lhs, rhs, lval.layout().ty),
 440                         _ => unimplemented!("binop {:?} for {:?}", bin_op, ty),
 441                     };
 442                     lval.write_cvalue(fx, res);
 443                 }
 444                 Rvalue::CheckedBinaryOp(bin_op, lhs, rhs) => {
 445                     let ty = fx.monomorphize(&lhs.ty(fx.mir, fx.tcx));
 446                     let lhs = trans_operand(fx, lhs);
 447                     let rhs = trans_operand(fx, rhs);
 448
 449                     let res = match ty.sty {
 450                         ty::Uint(_) => {
 451                             trans_checked_int_binop(fx, *bin_op, lhs, rhs, lval.layout().ty, false)
 452                         }
 453                         ty::Int(_) => {
 454                             trans_checked_int_binop(fx, *bin_op, lhs, rhs, lval.layout().ty, true)
 455                         }
 456                         _ => unimplemented!("checked binop {:?} for {:?}", bin_op, ty),
 457                     };
 458                     lval.write_cvalue(fx, res);
 459                 }
 460                 Rvalue::UnaryOp(un_op, operand) => {
 461                     let operand = trans_operand(fx, operand);
 462                     let layout = operand.layout();
 463                     let val = operand.load_scalar(fx);
 464                     let res = match un_op {
 465                         UnOp::Not => {
 466                             match layout.ty.sty {
 467                                 ty::Bool => {
 468                                     let val = fx.bcx.ins().uextend(types::I32, val); // WORKAROUND for CraneStation/cranelift#466
 469                                     let res = fx.bcx.ins().icmp_imm(IntCC::Equal, val, 0);
 470                                     fx.bcx.ins().bint(types::I8, res)
 471                                 }
 472                                 ty::Uint(_) | ty::Int(_) => fx.bcx.ins().bnot(val),
 473                                 _ => unimplemented!("un op Not for {:?}", layout.ty),
 474                             }
 475                         }
 476                         UnOp::Neg => match layout.ty.sty {
 477                             ty::Int(_) => {
 478                                 let clif_ty = fx.clif_type(layout.ty).unwrap();
 479                                 let zero = fx.bcx.ins().iconst(clif_ty, 0);
 480                                 fx.bcx.ins().isub(zero, val)
 481                             }
 482                             ty::Float(_) => fx.bcx.ins().fneg(val),
 483                             _ => unimplemented!("un op Neg for {:?}", layout.ty),
 484                         },
 485                     };
 486                     lval.write_cvalue(fx, CValue::ByVal(res, layout));
 487                 }
 488                 Rvalue::Cast(CastKind::Pointer(PointerCast::ReifyFnPointer), operand, ty) => {
 489                     let layout = fx.layout_of(ty);
 490                     match fx
 491                         .monomorphize(&operand.ty(&fx.mir.local_decls, fx.tcx))
 492                         .sty
 493                     {
 494                         ty::FnDef(def_id, substs) => {
 495                             let func_ref = fx.get_function_ref(
 496                                 Instance::resolve(fx.tcx, ParamEnv::reveal_all(), def_id, substs)
 497                                     .unwrap(),
 498                             );
 499                             let func_addr = fx.bcx.ins().func_addr(fx.pointer_type, func_ref);
 500                             lval.write_cvalue(fx, CValue::ByVal(func_addr, layout));
 501                         }
 502                         _ => bug!("Trying to ReifyFnPointer on non FnDef {:?}", ty),
 503                     }
 504                 }
 505                 Rvalue::Cast(CastKind::Pointer(PointerCast::UnsafeFnPointer), operand, ty)
 506                 | Rvalue::Cast(CastKind::Pointer(PointerCast::MutToConstPointer), operand, ty) => {
 507                     let operand = trans_operand(fx, operand);
 508                     let layout = fx.layout_of(ty);
 509                     lval.write_cvalue(fx, operand.unchecked_cast_to(layout));
 510                 }
 511                 Rvalue::Cast(CastKind::Misc, operand, to_ty) => {
 512                     let operand = trans_operand(fx, operand);
 513                     let from_ty = operand.layout().ty;
 514
 515                     fn is_fat_ptr<'a, 'tcx: 'a>(fx: &FunctionCx<'a, 'tcx, impl Backend>, ty: Ty<'tcx>) -> bool {
 516                         ty
 517                             .builtin_deref(true)
 518                             .map(|ty::TypeAndMut {ty: pointee_ty, mutbl: _ }| fx.layout_of(pointee_ty).is_unsized())
 519                             .unwrap_or(false)
 520                     }
 521
 522                     if is_fat_ptr(fx, from_ty) {
 523                         if is_fat_ptr(fx, to_ty) {
 524                             // fat-ptr -> fat-ptr
 525                             lval.write_cvalue(fx, operand.unchecked_cast_to(dest_layout));
 526                         } else {
 527                             // fat-ptr -> thin-ptr
 528                             let (ptr, _extra) = operand.load_scalar_pair(fx);
 529                             lval.write_cvalue(fx, CValue::ByVal(ptr, dest_layout))
 530                         }
 531                     } else if let ty::Adt(adt_def, _substs) = from_ty.sty {
 532                         // enum -> discriminant value
 533                         assert!(adt_def.is_enum());
 534                         match to_ty.sty {
 535                             ty::Uint(_) | ty::Int(_) => {},
 536                             _ => unreachable!("cast adt {} -> {}", from_ty, to_ty),
 537                         }
 538
 539                         // FIXME avoid forcing to stack
 540                         let place =
 541                             CPlace::Addr(operand.force_stack(fx), None, operand.layout());
 542                         let discr = trans_get_discriminant(fx, place, fx.layout_of(to_ty));
 543                         lval.write_cvalue(fx, discr);
 544                     } else {
 545                         let from_clif_ty = fx.clif_type(from_ty).unwrap();
 546                         let to_clif_ty = fx.clif_type(to_ty).unwrap();
 547                         let from = operand.load_scalar(fx);
 548
 549                         let signed = match from_ty.sty {
 550                             ty::Ref(..) | ty::RawPtr(..) | ty::FnPtr(..) | ty::Char | ty::Uint(..) | ty::Bool => false,
 551                             ty::Int(..) => true,
 552                             ty::Float(..) => false, // `signed` is unused for floats
 553                             _ => panic!("{}", from_ty),
 554                         };
 555
 556                         let res = if from_clif_ty.is_int() && to_clif_ty.is_int() {
 557                             // int-like -> int-like
 558                             crate::common::clif_intcast(
 559                                 fx,
 560                                 from,
 561                                 to_clif_ty,
 562                                 signed,
 563                             )
 564                         } else if from_clif_ty.is_int() && to_clif_ty.is_float() {
 565                             // int-like -> float
 566                             // FIXME missing encoding for fcvt_from_sint.f32.i8
 567                             let from = if from_clif_ty == types::I8 || from_clif_ty == types::I16 {
 568                                 fx.bcx.ins().uextend(types::I32, from)
 569                             } else {
 570                                 from
 571                             };
 572                             if signed {
 573                                 fx.bcx.ins().fcvt_from_sint(to_clif_ty, from)
 574                             } else {
 575                                 fx.bcx.ins().fcvt_from_uint(to_clif_ty, from)
 576                             }
 577                         } else if from_clif_ty.is_float() && to_clif_ty.is_int() {
 578                             // float -> int-like
 579                             let from = operand.load_scalar(fx);
 580                             if signed {
 581                                 fx.bcx.ins().fcvt_to_sint_sat(to_clif_ty, from)
 582                             } else {
 583                                 fx.bcx.ins().fcvt_to_uint_sat(to_clif_ty, from)
 584                             }
 585                         } else if from_clif_ty.is_float() && to_clif_ty.is_float() {
 586                             // float -> float
 587                             match (from_clif_ty, to_clif_ty) {
 588                                 (types::F32, types::F64) => {
 589                                     fx.bcx.ins().fpromote(types::F64, from)
 590                                 }
 591                                 (types::F64, types::F32) => {
 592                                     fx.bcx.ins().fdemote(types::F32, from)
 593                                 }
 594                                 _ => from,
 595                             }
 596                         } else {
 597                             unimpl!("rval misc {:?} {:?}", from_ty, to_ty)
 598                         };
 599                         lval.write_cvalue(fx, CValue::ByVal(res, dest_layout));
 600                     }
 601                 }
 602                 Rvalue::Cast(CastKind::Pointer(PointerCast::ClosureFnPointer(_)), operand, _ty) => {
 603                     let operand = trans_operand(fx, operand);
 604                     match operand.layout().ty.sty {
 605                         ty::Closure(def_id, substs) => {
 606                             let instance = Instance::resolve_closure(
 607                                 fx.tcx,
 608                                 def_id,
 609                                 substs,
 610                                 ty::ClosureKind::FnOnce,
 611                             );
 612                             let func_ref = fx.get_function_ref(instance);
 613                             let func_addr = fx.bcx.ins().func_addr(fx.pointer_type, func_ref);
 614                             lval.write_cvalue(fx, CValue::ByVal(func_addr, lval.layout()));
 615                         }
 616                         _ => {
 617                             bug!("{} cannot be cast to a fn ptr", operand.layout().ty)
 618                         }
 619                     }
 620                 }
 621                 Rvalue::Cast(CastKind::Pointer(PointerCast::Unsize), operand, _ty) => {
 622                     let operand = trans_operand(fx, operand);
 623                     operand.unsize_value(fx, lval);
 624                 }
 625                 Rvalue::Discriminant(place) => {
 626                     let place = trans_place(fx, place);
 627                     let discr = trans_get_discriminant(fx, place, dest_layout);
 628                     lval.write_cvalue(fx, discr);
 629                 }
 630                 Rvalue::Repeat(operand, times) => {
 631                     let operand = trans_operand(fx, operand);
 632                     for i in 0..*times {
 633                         let index = fx.bcx.ins().iconst(fx.pointer_type, i as i64);
 634                         let to = lval.place_index(fx, index);
 635                         to.write_cvalue(fx, operand);
 636                     }
 637                 }
 638                 Rvalue::Len(place) => {
 639                     let place = trans_place(fx, place);
 640                     let usize_layout = fx.layout_of(fx.tcx.types.usize);
 641                     let len = codegen_array_len(fx, place);
 642                     lval.write_cvalue(fx, CValue::ByVal(len, usize_layout));
 643                 }
 644                 Rvalue::NullaryOp(NullOp::Box, content_ty) => {
 645                     use rustc::middle::lang_items::ExchangeMallocFnLangItem;
 646
 647                     let usize_type = fx.clif_type(fx.tcx.types.usize).unwrap();
 648                     let layout = fx.layout_of(content_ty);
 649                     let llsize = fx.bcx.ins().iconst(usize_type, layout.size.bytes() as i64);
 650                     let llalign = fx
 651                         .bcx
 652                         .ins()
 653                         .iconst(usize_type, layout.align.abi.bytes() as i64);
 654                     let box_layout = fx.layout_of(fx.tcx.mk_box(content_ty));
 655
 656                     // Allocate space:
 657                     let def_id = match fx.tcx.lang_items().require(ExchangeMallocFnLangItem) {
 658                         Ok(id) => id,
 659                         Err(s) => {
 660                             fx.tcx
 661                                 .sess
 662                                 .fatal(&format!("allocation of `{}` {}", box_layout.ty, s));
 663                         }
 664                     };
 665                     let instance = ty::Instance::mono(fx.tcx, def_id);
 666                     let func_ref = fx.get_function_ref(instance);
 667                     let call = fx.bcx.ins().call(func_ref, &[llsize, llalign]);
 668                     let ptr = fx.bcx.inst_results(call)[0];
 669                     lval.write_cvalue(fx, CValue::ByVal(ptr, box_layout));
 670                 }
 671                 Rvalue::NullaryOp(NullOp::SizeOf, ty) => {
 672                     assert!(lval
 673                         .layout()
 674                         .ty
 675                         .is_sized(fx.tcx.at(DUMMY_SP), ParamEnv::reveal_all()));
 676                     let ty_size = fx.layout_of(ty).size.bytes();
 677                     let val = CValue::const_val(fx, fx.tcx.types.usize, ty_size as i64);
 678                     lval.write_cvalue(fx, val);
 679                 }
 680                 Rvalue::Aggregate(kind, operands) => match **kind {
 681                     AggregateKind::Array(_ty) => {
 682                         for (i, operand) in operands.into_iter().enumerate() {
 683                             let operand = trans_operand(fx, operand);
 684                             let index = fx.bcx.ins().iconst(fx.pointer_type, i as i64);
 685                             let to = lval.place_index(fx, index);
 686                             to.write_cvalue(fx, operand);
 687                         }
 688                     }
 689                     _ => unimpl!("shouldn't exist at trans {:?}", rval),
 690                 },
 691             }
 692         }
 693         StatementKind::StorageLive(_)
 694         | StatementKind::StorageDead(_)
 695         | StatementKind::Nop
 696         | StatementKind::FakeRead(..)
 697         | StatementKind::Retag { .. }
 698         | StatementKind::AscribeUserType(..) => {}
 699
 700         StatementKind::InlineAsm { .. } => unimpl!("Inline assembly is not supported"),
 701     }
 702 }
 703
 704 fn codegen_array_len<'a, 'tcx: 'a>(
 705     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 706     place: CPlace<'tcx>,
 707 ) -> Value {
 708     match place.layout().ty.sty {
 709         ty::Array(_elem_ty, len) => {
 710             let len = crate::constant::force_eval_const(fx, len).unwrap_usize(fx.tcx) as i64;
 711             fx.bcx.ins().iconst(fx.pointer_type, len)
 712         }
 713         ty::Slice(_elem_ty) => place
 714             .to_addr_maybe_unsized(fx)
 715             .1
 716             .expect("Length metadata for slice place"),
 717         _ => bug!("Rvalue::Len({:?})", place),
 718     }
 719 }
 720
 721 pub fn trans_get_discriminant<'a, 'tcx: 'a>(
 722     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 723     place: CPlace<'tcx>,
 724     dest_layout: TyLayout<'tcx>,
 725 ) -> CValue<'tcx> {
 726     let layout = place.layout();
 727
 728     if layout.abi == layout::Abi::Uninhabited {
 729         return trap_unreachable_ret_value(fx, dest_layout, "[panic] Tried to get discriminant for uninhabited type.");
 730     }
 731
 732     let (discr_scalar, discr_index, discr_kind) = match &layout.variants {
 733         layout::Variants::Single { index } => {
 734             let discr_val = layout
 735                 .ty
 736                 .ty_adt_def()
 737                 .map_or(index.as_u32() as u128, |def| {
 738                     def.discriminant_for_variant(fx.tcx, *index).val
 739                 });
 740             return CValue::const_val(fx, dest_layout.ty, discr_val as u64 as i64);
 741         }
 742         layout::Variants::Multiple { discr, discr_index, discr_kind, variants: _ } => {
 743             (discr, *discr_index, discr_kind)
 744         }
 745     };
 746
 747     let discr = place.place_field(fx, mir::Field::new(discr_index)).to_cvalue(fx);
 748     let discr_ty = discr.layout().ty;
 749     let lldiscr = discr.load_scalar(fx);
 750     match discr_kind {
 751         layout::DiscriminantKind::Tag => {
 752             let signed = match discr_scalar.value {
 753                 layout::Int(_, signed) => signed,
 754                 _ => false,
 755             };
 756             let val = clif_intcast(fx, lldiscr, fx.clif_type(dest_layout.ty).unwrap(), signed);
 757             return CValue::ByVal(val, dest_layout);
 758         }
 759         layout::DiscriminantKind::Niche {
 760             dataful_variant,
 761             ref niche_variants,
 762             niche_start,
 763         } => {
 764             let niche_llty = fx.clif_type(discr_ty).unwrap();
 765             let dest_clif_ty = fx.clif_type(dest_layout.ty).unwrap();
 766             if niche_variants.start() == niche_variants.end() {
 767                 let b = fx
 768                     .bcx
 769                     .ins()
 770                     .icmp_imm(IntCC::Equal, lldiscr, *niche_start as u64 as i64);
 771                 let if_true = fx
 772                     .bcx
 773                     .ins()
 774                     .iconst(dest_clif_ty, niche_variants.start().as_u32() as i64);
 775                 let if_false = fx
 776                     .bcx
 777                     .ins()
 778                     .iconst(dest_clif_ty, dataful_variant.as_u32() as i64);
 779                 let val = fx.bcx.ins().select(b, if_true, if_false);
 780                 return CValue::ByVal(val, dest_layout);
 781             } else {
 782                 // Rebase from niche values to discriminant values.
 783                 let delta = niche_start.wrapping_sub(niche_variants.start().as_u32() as u128);
 784                 let delta = fx.bcx.ins().iconst(niche_llty, delta as u64 as i64);
 785                 let lldiscr = fx.bcx.ins().isub(lldiscr, delta);
 786                 let b = fx.bcx.ins().icmp_imm(
 787                     IntCC::UnsignedLessThanOrEqual,
 788                     lldiscr,
 789                     niche_variants.end().as_u32() as i64,
 790                 );
 791                 let if_true =
 792                     clif_intcast(fx, lldiscr, fx.clif_type(dest_layout.ty).unwrap(), false);
 793                 let if_false = fx
 794                     .bcx
 795                     .ins()
 796                     .iconst(dest_clif_ty, dataful_variant.as_u32() as i64);
 797                 let val = fx.bcx.ins().select(b, if_true, if_false);
 798                 return CValue::ByVal(val, dest_layout);
 799             }
 800         }
 801     }
 802 }
 803
 804 macro_rules! binop_match {
 805     (@single $fx:expr, $bug_fmt:expr, $var:expr, $signed:expr, $lhs:expr, $rhs:expr, $ret_ty:expr, bug) => {
 806         bug!("binop {} on {} lhs: {:?} rhs: {:?}", stringify!($var), $bug_fmt, $lhs, $rhs)
 807     };
 808     (@single $fx:expr, $bug_fmt:expr, $var:expr, $signed:expr, $lhs:expr, $rhs:expr, $ret_ty:expr, icmp($cc:ident)) => {{
 809         assert_eq!($fx.tcx.types.bool, $ret_ty);
 810         let ret_layout = $fx.layout_of($ret_ty);
 811
 812         let b = $fx.bcx.ins().icmp(IntCC::$cc, $lhs, $rhs);
 813         CValue::ByVal($fx.bcx.ins().bint(types::I8, b), ret_layout)
 814     }};
 815     (@single $fx:expr, $bug_fmt:expr, $var:expr, $signed:expr, $lhs:expr, $rhs:expr, $ret_ty:expr, fcmp($cc:ident)) => {{
 816         assert_eq!($fx.tcx.types.bool, $ret_ty);
 817         let ret_layout = $fx.layout_of($ret_ty);
 818         let b = $fx.bcx.ins().fcmp(FloatCC::$cc, $lhs, $rhs);
 819         CValue::ByVal($fx.bcx.ins().bint(types::I8, b), ret_layout)
 820     }};
 821     (@single $fx:expr, $bug_fmt:expr, $var:expr, $signed:expr, $lhs:expr, $rhs:expr, $ret_ty:expr, custom(|| $body:expr)) => {{
 822         $body
 823     }};
 824     (@single $fx:expr, $bug_fmt:expr, $var:expr, $signed:expr, $lhs:expr, $rhs:expr, $ret_ty:expr, $name:ident) => {{
 825         let ret_layout = $fx.layout_of($ret_ty);
 826         CValue::ByVal($fx.bcx.ins().$name($lhs, $rhs), ret_layout)
 827     }};
 828     (
 829         $fx:expr, $bin_op:expr, $signed:expr, $lhs:expr, $rhs:expr, $ret_ty:expr, $bug_fmt:expr;
 830         $(
 831             $var:ident ($sign:pat) $name:tt $( ( $($next:tt)* ) )? ;
 832         )*
 833     ) => {{
 834         let lhs = $lhs.load_scalar($fx);
 835         let rhs = $rhs.load_scalar($fx);
 836         match ($bin_op, $signed) {
 837             $(
 838                 (BinOp::$var, $sign) => binop_match!(@single $fx, $bug_fmt, $var, $signed, lhs, rhs, $ret_ty, $name $( ( $($next)* ) )?),
 839             )*
 840         }
 841     }}
 842 }
 843
 844 fn trans_bool_binop<'a, 'tcx: 'a>(
 845     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 846     bin_op: BinOp,
 847     lhs: CValue<'tcx>,
 848     rhs: CValue<'tcx>,
 849     ty: Ty<'tcx>,
 850 ) -> CValue<'tcx> {
 851     let res = binop_match! {
 852         fx, bin_op, false, lhs, rhs, ty, "bool";
 853         Add (_) bug;
 854         Sub (_) bug;
 855         Mul (_) bug;
 856         Div (_) bug;
 857         Rem (_) bug;
 858         BitXor (_) bxor;
 859         BitAnd (_) band;
 860         BitOr (_) bor;
 861         Shl (_) bug;
 862         Shr (_) bug;
 863
 864         Eq (_) icmp(Equal);
 865         Lt (_) icmp(UnsignedLessThan);
 866         Le (_) icmp(UnsignedLessThanOrEqual);
 867         Ne (_) icmp(NotEqual);
 868         Ge (_) icmp(UnsignedGreaterThanOrEqual);
 869         Gt (_) icmp(UnsignedGreaterThan);
 870
 871         Offset (_) bug;
 872     };
 873
 874     res
 875 }
 876
 877 pub fn trans_int_binop<'a, 'tcx: 'a>(
 878     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 879     bin_op: BinOp,
 880     lhs: CValue<'tcx>,
 881     rhs: CValue<'tcx>,
 882     out_ty: Ty<'tcx>,
 883     signed: bool,
 884 ) -> CValue<'tcx> {
 885     if bin_op != BinOp::Shl && bin_op != BinOp::Shr {
 886         assert_eq!(
 887             lhs.layout().ty,
 888             rhs.layout().ty,
 889             "int binop requires lhs and rhs of same type"
 890         );
 891     }
 892     binop_match! {
 893         fx, bin_op, signed, lhs, rhs, out_ty, "int/uint";
 894         Add (_) iadd;
 895         Sub (_) isub;
 896         Mul (_) imul;
 897         Div (false) udiv;
 898         Div (true) sdiv;
 899         Rem (false) urem;
 900         Rem (true) srem;
 901         BitXor (_) bxor;
 902         BitAnd (_) band;
 903         BitOr (_) bor;
 904         Shl (_) ishl;
 905         Shr (false) ushr;
 906         Shr (true) sshr;
 907
 908         Eq (_) icmp(Equal);
 909         Lt (false) icmp(UnsignedLessThan);
 910         Lt (true) icmp(SignedLessThan);
 911         Le (false) icmp(UnsignedLessThanOrEqual);
 912         Le (true) icmp(SignedLessThanOrEqual);
 913         Ne (_) icmp(NotEqual);
 914         Ge (false) icmp(UnsignedGreaterThanOrEqual);
 915         Ge (true) icmp(SignedGreaterThanOrEqual);
 916         Gt (false) icmp(UnsignedGreaterThan);
 917         Gt (true) icmp(SignedGreaterThan);
 918
 919         Offset (_) bug;
 920     }
 921 }
 922
 923 pub fn trans_checked_int_binop<'a, 'tcx: 'a>(
 924     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 925     bin_op: BinOp,
 926     in_lhs: CValue<'tcx>,
 927     in_rhs: CValue<'tcx>,
 928     out_ty: Ty<'tcx>,
 929     signed: bool,
 930 ) -> CValue<'tcx> {
 931     if bin_op != BinOp::Shl && bin_op != BinOp::Shr {
 932         assert_eq!(
 933             in_lhs.layout().ty,
 934             in_rhs.layout().ty,
 935             "checked int binop requires lhs and rhs of same type"
 936         );
 937     }
 938
 939     let lhs = in_lhs.load_scalar(fx);
 940     let rhs = in_rhs.load_scalar(fx);
 941     let res = match bin_op {
 942         BinOp::Add => fx.bcx.ins().iadd(lhs, rhs),
 943         BinOp::Sub => fx.bcx.ins().isub(lhs, rhs),
 944         BinOp::Mul => fx.bcx.ins().imul(lhs, rhs),
 945         BinOp::Shl => fx.bcx.ins().ishl(lhs, rhs),
 946         BinOp::Shr => {
 947             if !signed {
 948                 fx.bcx.ins().ushr(lhs, rhs)
 949             } else {
 950                 fx.bcx.ins().sshr(lhs, rhs)
 951             }
 952         }
 953         _ => bug!(
 954             "binop {:?} on checked int/uint lhs: {:?} rhs: {:?}",
 955             bin_op,
 956             in_lhs,
 957             in_rhs
 958         ),
 959     };
 960
 961     // TODO: check for overflow
 962     let has_overflow = fx.bcx.ins().iconst(types::I8, 0);
 963
 964     let out_place = CPlace::new_stack_slot(fx, out_ty);
 965     let out_layout = out_place.layout();
 966     out_place.write_cvalue(fx, CValue::ByValPair(res, has_overflow, out_layout));
 967
 968     out_place.to_cvalue(fx)
 969 }
 970
 971 fn trans_float_binop<'a, 'tcx: 'a>(
 972     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 973     bin_op: BinOp,
 974     lhs: CValue<'tcx>,
 975     rhs: CValue<'tcx>,
 976     ty: Ty<'tcx>,
 977 ) -> CValue<'tcx> {
 978     let res = binop_match! {
 979         fx, bin_op, false, lhs, rhs, ty, "float";
 980         Add (_) fadd;
 981         Sub (_) fsub;
 982         Mul (_) fmul;
 983         Div (_) fdiv;
 984         Rem (_) custom(|| {
 985             assert_eq!(lhs.layout().ty, ty);
 986             assert_eq!(rhs.layout().ty, ty);
 987             match ty.sty {
 988                 ty::Float(FloatTy::F32) => fx.easy_call("fmodf", &[lhs, rhs], ty),
 989                 ty::Float(FloatTy::F64) => fx.easy_call("fmod", &[lhs, rhs], ty),
 990                 _ => bug!(),
 991             }
 992         });
 993         BitXor (_) bxor;
 994         BitAnd (_) band;
 995         BitOr (_) bor;
 996         Shl (_) bug;
 997         Shr (_) bug;
 998
 999         Eq (_) fcmp(Equal);
1000         Lt (_) fcmp(LessThan);
1001         Le (_) fcmp(LessThanOrEqual);
1002         Ne (_) fcmp(NotEqual);
1003         Ge (_) fcmp(GreaterThanOrEqual);
1004         Gt (_) fcmp(GreaterThan);
1005
1006         Offset (_) bug;
1007     };
1008
1009     res
1010 }
1011
1012 fn trans_char_binop<'a, 'tcx: 'a>(
1013     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
1014     bin_op: BinOp,
1015     lhs: CValue<'tcx>,
1016     rhs: CValue<'tcx>,
1017     ty: Ty<'tcx>,
1018 ) -> CValue<'tcx> {
1019     let res = binop_match! {
1020         fx, bin_op, false, lhs, rhs, ty, "char";
1021         Add (_) bug;
1022         Sub (_) bug;
1023         Mul (_) bug;
1024         Div (_) bug;
1025         Rem (_) bug;
1026         BitXor (_) bug;
1027         BitAnd (_) bug;
1028         BitOr (_) bug;
1029         Shl (_) bug;
1030         Shr (_) bug;
1031
1032         Eq (_) icmp(Equal);
1033         Lt (_) icmp(UnsignedLessThan);
1034         Le (_) icmp(UnsignedLessThanOrEqual);
1035         Ne (_) icmp(NotEqual);
1036         Ge (_) icmp(UnsignedGreaterThanOrEqual);
1037         Gt (_) icmp(UnsignedGreaterThan);
1038
1039         Offset (_) bug;
1040     };
1041
1042     res
1043 }
1044
1045 fn trans_ptr_binop<'a, 'tcx: 'a>(
1046     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
1047     bin_op: BinOp,
1048     lhs: CValue<'tcx>,
1049     rhs: CValue<'tcx>,
1050     ret_ty: Ty<'tcx>,
1051 ) -> CValue<'tcx> {
1052     let not_fat = match lhs.layout().ty.sty {
1053         ty::RawPtr(TypeAndMut { ty, mutbl: _ }) => {
1054             ty.is_sized(fx.tcx.at(DUMMY_SP), ParamEnv::reveal_all())
1055         }
1056         ty::FnPtr(..) => true,
1057         _ => bug!("trans_ptr_binop on non ptr"),
1058     };
1059     if not_fat {
1060         if let BinOp::Offset = bin_op {
1061             let (base, offset) = (lhs, rhs.load_scalar(fx));
1062             let pointee_ty = base.layout().ty.builtin_deref(true).unwrap().ty;
1063             let pointee_size = fx.layout_of(pointee_ty).size.bytes();
1064             let ptr_diff = fx.bcx.ins().imul_imm(offset, pointee_size as i64);
1065             let base_val = base.load_scalar(fx);
1066             let res = fx.bcx.ins().iadd(base_val, ptr_diff);
1067             return CValue::ByVal(res, base.layout());
1068         }
1069
1070         binop_match! {
1071             fx, bin_op, false, lhs, rhs, ret_ty, "ptr";
1072             Add (_) bug;
1073             Sub (_) bug;
1074             Mul (_) bug;
1075             Div (_) bug;
1076             Rem (_) bug;
1077             BitXor (_) bug;
1078             BitAnd (_) bug;
1079             BitOr (_) bug;
1080             Shl (_) bug;
1081             Shr (_) bug;
1082
1083             Eq (_) icmp(Equal);
1084             Lt (_) icmp(UnsignedLessThan);
1085             Le (_) icmp(UnsignedLessThanOrEqual);
1086             Ne (_) icmp(NotEqual);
1087             Ge (_) icmp(UnsignedGreaterThanOrEqual);
1088             Gt (_) icmp(UnsignedGreaterThan);
1089
1090             Offset (_) bug; // Handled above
1091         }
1092     } else {
1093         let (lhs_ptr, lhs_extra) = lhs.load_scalar_pair(fx);
1094         let (rhs_ptr, rhs_extra) = rhs.load_scalar_pair(fx);
1095         let res = match bin_op {
1096             BinOp::Eq => {
1097                 let ptr_eq = fx.bcx.ins().icmp(IntCC::Equal, lhs_ptr, rhs_ptr);
1098                 let extra_eq = fx.bcx.ins().icmp(IntCC::Equal, lhs_extra, rhs_extra);
1099                 fx.bcx.ins().band(ptr_eq, extra_eq)
1100             }
1101             BinOp::Ne => {
1102                 let ptr_ne = fx.bcx.ins().icmp(IntCC::NotEqual, lhs_ptr, rhs_ptr);
1103                 let extra_ne = fx.bcx.ins().icmp(IntCC::NotEqual, lhs_extra, rhs_extra);
1104                 fx.bcx.ins().bor(ptr_ne, extra_ne)
1105             }
1106             _ => unimplemented!(
1107                 "trans_ptr_binop({:?}, <fat ptr>, <fat ptr>) not implemented",
1108                 bin_op
1109             ),
1110         };
1111
1112         assert_eq!(fx.tcx.types.bool, ret_ty);
1113         let ret_layout = fx.layout_of(ret_ty);
1114         CValue::ByVal(fx.bcx.ins().bint(types::I8, res), ret_layout)
1115     }
1116 }
1117
1118 pub fn trans_place<'a, 'tcx: 'a>(
1119     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
1120     place: &Place<'tcx>,
1121 ) -> CPlace<'tcx> {
1122     match place {
1123         Place::Base(base) => match base {
1124             PlaceBase::Local(local) => fx.get_local_place(*local),
1125             PlaceBase::Static(static_) => match static_.kind {
1126                 StaticKind::Static(def_id) => {
1127                     crate::constant::codegen_static_ref(fx, def_id, static_.ty)
1128                 }
1129                 StaticKind::Promoted(promoted) => {
1130                     crate::constant::trans_promoted(fx, promoted, static_.ty)
1131                 }
1132             }
1133         }
1134         Place::Projection(projection) => {
1135             let base = trans_place(fx, &projection.base);
1136             match projection.elem {
1137                 ProjectionElem::Deref => base.place_deref(fx),
1138                 ProjectionElem::Field(field, _ty) => base.place_field(fx, field),
1139                 ProjectionElem::Index(local) => {
1140                     let index = fx.get_local_place(local).to_cvalue(fx).load_scalar(fx);
1141                     base.place_index(fx, index)
1142                 }
1143                 ProjectionElem::ConstantIndex {
1144                     offset,
1145                     min_length: _,
1146                     from_end,
1147                 } => {
1148                     let index = if !from_end {
1149                         fx.bcx.ins().iconst(fx.pointer_type, offset as i64)
1150                     } else {
1151                         let len = codegen_array_len(fx, base);
1152                         fx.bcx.ins().iadd_imm(len, -(offset as i64))
1153                     };
1154                     base.place_index(fx, index)
1155                 }
1156                 ProjectionElem::Subslice { from, to } => {
1157                     // These indices are generated by slice patterns.
1158                     // slice[from:-to] in Python terms.
1159
1160                     match base.layout().ty.sty {
1161                         ty::Array(elem_ty, len) => {
1162                             let elem_layout = fx.layout_of(elem_ty);
1163                             let ptr = base.to_addr(fx);
1164                             let len = crate::constant::force_eval_const(fx, len).unwrap_usize(fx.tcx);
1165                             CPlace::Addr(
1166                                 fx.bcx.ins().iadd_imm(ptr, elem_layout.size.bytes() as i64 * from as i64),
1167                                 None,
1168                                 fx.layout_of(fx.tcx.mk_array(elem_ty, len - from as u64 - to as u64)),
1169                             )
1170                         }
1171                         ty::Slice(elem_ty) => {
1172                             let elem_layout = fx.layout_of(elem_ty);
1173                             let (ptr, len) = base.to_addr_maybe_unsized(fx);
1174                             let len = len.unwrap();
1175                             CPlace::Addr(
1176                                 fx.bcx.ins().iadd_imm(ptr, elem_layout.size.bytes() as i64 * from as i64),
1177                                 Some(fx.bcx.ins().iadd_imm(len, -(from as i64 + to as i64))),
1178                                 base.layout(),
1179                             )
1180                         }
1181                         _ => unreachable!(),
1182                     }
1183                 }
1184                 ProjectionElem::Downcast(_adt_def, variant) => base.downcast_variant(fx, variant),
1185             }
1186         }
1187     }
1188 }
1189
1190 pub fn trans_operand<'a, 'tcx>(
1191     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
1192     operand: &Operand<'tcx>,
1193 ) -> CValue<'tcx> {
1194     match operand {
1195         Operand::Move(place) | Operand::Copy(place) => {
1196             let cplace = trans_place(fx, place);
1197             cplace.to_cvalue(fx)
1198         }
1199         Operand::Constant(const_) => crate::constant::trans_constant(fx, const_),
1200     }
1201 }