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<'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<'tcx>(TyCtxt<'tcx>, bool);
  22
  23         impl<'tcx> rustc::ty::fold::TypeVisitor<'tcx> for UI128Visitor<'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 drop_place = trans_place(fx, location);
 290                 crate::abi::codegen_drop(fx, drop_place);
 291
 292                 let target_ebb = fx.get_ebb(*target);
 293                 fx.bcx.ins().jump(target_ebb, &[]);
 294             }
 295         };
 296     }
 297
 298     fx.bcx.seal_all_blocks();
 299     fx.bcx.finalize();
 300 }
 301
 302 fn trans_stmt<'a, 'tcx: 'a>(
 303     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 304     cur_ebb: Ebb,
 305     stmt: &Statement<'tcx>,
 306 ) {
 307     let _print_guard = PrintOnPanic(|| format!("stmt {:?}", stmt));
 308
 309     fx.set_debug_loc(stmt.source_info);
 310
 311     #[cfg(debug_assertions)]
 312     match &stmt.kind {
 313         StatementKind::StorageLive(..) | StatementKind::StorageDead(..) => {} // Those are not very useful
 314         _ => {
 315             let inst = fx.bcx.func.layout.last_inst(cur_ebb).unwrap();
 316             fx.add_comment(inst, format!("{:?}", stmt));
 317         }
 318     }
 319
 320     match &stmt.kind {
 321         StatementKind::SetDiscriminant {
 322             place,
 323             variant_index,
 324         } => {
 325             let place = trans_place(fx, place);
 326             let layout = place.layout();
 327             if layout.for_variant(&*fx, *variant_index).abi == layout::Abi::Uninhabited {
 328                 return;
 329             }
 330             match layout.variants {
 331                 layout::Variants::Single { index } => {
 332                     assert_eq!(index, *variant_index);
 333                 }
 334                 layout::Variants::Multiple {
 335                     discr: _,
 336                     discr_index,
 337                     discr_kind: layout::DiscriminantKind::Tag,
 338                     variants: _,
 339                 } => {
 340                     let ptr = place.place_field(fx, mir::Field::new(discr_index));
 341                     let to = layout
 342                         .ty
 343                         .ty_adt_def()
 344                         .unwrap()
 345                         .discriminant_for_variant(fx.tcx, *variant_index)
 346                         .val;
 347                     let discr = CValue::const_val(fx, ptr.layout().ty, to as u64 as i64);
 348                     ptr.write_cvalue(fx, discr);
 349                 }
 350                 layout::Variants::Multiple {
 351                     discr: _,
 352                     discr_index,
 353                     discr_kind: layout::DiscriminantKind::Niche {
 354                         dataful_variant,
 355                         ref niche_variants,
 356                         niche_start,
 357                     },
 358                     variants: _,
 359                 } => {
 360                     if *variant_index != dataful_variant {
 361                         let niche = place.place_field(fx, mir::Field::new(discr_index));
 362                         //let niche_llty = niche.layout.immediate_llvm_type(bx.cx);
 363                         let niche_value =
 364                             ((variant_index.as_u32() - niche_variants.start().as_u32()) as u128)
 365                                 .wrapping_add(niche_start);
 366                         // FIXME(eddyb) Check the actual primitive type here.
 367                         let niche_llval = if niche_value == 0 {
 368                             CValue::const_val(fx, niche.layout().ty, 0)
 369                         } else {
 370                             CValue::const_val(fx, niche.layout().ty, niche_value as u64 as i64)
 371                         };
 372                         niche.write_cvalue(fx, niche_llval);
 373                     }
 374                 }
 375             }
 376         }
 377         StatementKind::Assign(to_place, rval) => {
 378             let lval = trans_place(fx, to_place);
 379             let dest_layout = lval.layout();
 380             match &**rval {
 381                 Rvalue::Use(operand) => {
 382                     let val = trans_operand(fx, operand);
 383                     lval.write_cvalue(fx, val);
 384                 }
 385                 Rvalue::Ref(_, _, place) => {
 386                     let place = trans_place(fx, place);
 387                     place.write_place_ref(fx, lval);
 388                 }
 389                 Rvalue::BinaryOp(bin_op, lhs, rhs) => {
 390                     let ty = fx.monomorphize(&lhs.ty(fx.mir, fx.tcx));
 391                     let lhs = trans_operand(fx, lhs);
 392                     let rhs = trans_operand(fx, rhs);
 393
 394                     let res = match ty.sty {
 395                         ty::Bool => trans_bool_binop(fx, *bin_op, lhs, rhs, lval.layout().ty),
 396                         ty::Uint(_) => {
 397                             trans_int_binop(fx, *bin_op, lhs, rhs, lval.layout().ty, false)
 398                         }
 399                         ty::Int(_) => {
 400                             trans_int_binop(fx, *bin_op, lhs, rhs, lval.layout().ty, true)
 401                         }
 402                         ty::Float(_) => trans_float_binop(fx, *bin_op, lhs, rhs, lval.layout().ty),
 403                         ty::Char => trans_char_binop(fx, *bin_op, lhs, rhs, lval.layout().ty),
 404                         ty::RawPtr(..) => trans_ptr_binop(fx, *bin_op, lhs, rhs, lval.layout().ty),
 405                         ty::FnPtr(..) => trans_ptr_binop(fx, *bin_op, lhs, rhs, lval.layout().ty),
 406                         _ => unimplemented!("binop {:?} for {:?}", bin_op, ty),
 407                     };
 408                     lval.write_cvalue(fx, res);
 409                 }
 410                 Rvalue::CheckedBinaryOp(bin_op, lhs, rhs) => {
 411                     let ty = fx.monomorphize(&lhs.ty(fx.mir, fx.tcx));
 412                     let lhs = trans_operand(fx, lhs);
 413                     let rhs = trans_operand(fx, rhs);
 414
 415                     let res = match ty.sty {
 416                         ty::Uint(_) => {
 417                             trans_checked_int_binop(fx, *bin_op, lhs, rhs, lval.layout().ty, false)
 418                         }
 419                         ty::Int(_) => {
 420                             trans_checked_int_binop(fx, *bin_op, lhs, rhs, lval.layout().ty, true)
 421                         }
 422                         _ => unimplemented!("checked binop {:?} for {:?}", bin_op, ty),
 423                     };
 424                     lval.write_cvalue(fx, res);
 425                 }
 426                 Rvalue::UnaryOp(un_op, operand) => {
 427                     let operand = trans_operand(fx, operand);
 428                     let layout = operand.layout();
 429                     let val = operand.load_scalar(fx);
 430                     let res = match un_op {
 431                         UnOp::Not => {
 432                             match layout.ty.sty {
 433                                 ty::Bool => {
 434                                     let val = fx.bcx.ins().uextend(types::I32, val); // WORKAROUND for CraneStation/cranelift#466
 435                                     let res = fx.bcx.ins().icmp_imm(IntCC::Equal, val, 0);
 436                                     fx.bcx.ins().bint(types::I8, res)
 437                                 }
 438                                 ty::Uint(_) | ty::Int(_) => fx.bcx.ins().bnot(val),
 439                                 _ => unimplemented!("un op Not for {:?}", layout.ty),
 440                             }
 441                         }
 442                         UnOp::Neg => match layout.ty.sty {
 443                             ty::Int(_) => {
 444                                 let clif_ty = fx.clif_type(layout.ty).unwrap();
 445                                 let zero = fx.bcx.ins().iconst(clif_ty, 0);
 446                                 fx.bcx.ins().isub(zero, val)
 447                             }
 448                             ty::Float(_) => fx.bcx.ins().fneg(val),
 449                             _ => unimplemented!("un op Neg for {:?}", layout.ty),
 450                         },
 451                     };
 452                     lval.write_cvalue(fx, CValue::by_val(res, layout));
 453                 }
 454                 Rvalue::Cast(CastKind::Pointer(PointerCast::ReifyFnPointer), operand, ty) => {
 455                     let layout = fx.layout_of(ty);
 456                     match fx
 457                         .monomorphize(&operand.ty(&fx.mir.local_decls, fx.tcx))
 458                         .sty
 459                     {
 460                         ty::FnDef(def_id, substs) => {
 461                             let func_ref = fx.get_function_ref(
 462                                 Instance::resolve(fx.tcx, ParamEnv::reveal_all(), def_id, substs)
 463                                     .unwrap(),
 464                             );
 465                             let func_addr = fx.bcx.ins().func_addr(fx.pointer_type, func_ref);
 466                             lval.write_cvalue(fx, CValue::by_val(func_addr, layout));
 467                         }
 468                         _ => bug!("Trying to ReifyFnPointer on non FnDef {:?}", ty),
 469                     }
 470                 }
 471                 Rvalue::Cast(CastKind::Pointer(PointerCast::UnsafeFnPointer), operand, ty)
 472                 | Rvalue::Cast(CastKind::Pointer(PointerCast::MutToConstPointer), operand, ty) => {
 473                     let operand = trans_operand(fx, operand);
 474                     let layout = fx.layout_of(ty);
 475                     lval.write_cvalue(fx, operand.unchecked_cast_to(layout));
 476                 }
 477                 Rvalue::Cast(CastKind::Misc, operand, to_ty) => {
 478                     let operand = trans_operand(fx, operand);
 479                     let from_ty = operand.layout().ty;
 480
 481                     fn is_fat_ptr<'a, 'tcx: 'a>(fx: &FunctionCx<'a, 'tcx, impl Backend>, ty: Ty<'tcx>) -> bool {
 482                         ty
 483                             .builtin_deref(true)
 484                             .map(|ty::TypeAndMut {ty: pointee_ty, mutbl: _ }| fx.layout_of(pointee_ty).is_unsized())
 485                             .unwrap_or(false)
 486                     }
 487
 488                     if is_fat_ptr(fx, from_ty) {
 489                         if is_fat_ptr(fx, to_ty) {
 490                             // fat-ptr -> fat-ptr
 491                             lval.write_cvalue(fx, operand.unchecked_cast_to(dest_layout));
 492                         } else {
 493                             // fat-ptr -> thin-ptr
 494                             let (ptr, _extra) = operand.load_scalar_pair(fx);
 495                             lval.write_cvalue(fx, CValue::by_val(ptr, dest_layout))
 496                         }
 497                     } else if let ty::Adt(adt_def, _substs) = from_ty.sty {
 498                         // enum -> discriminant value
 499                         assert!(adt_def.is_enum());
 500                         match to_ty.sty {
 501                             ty::Uint(_) | ty::Int(_) => {},
 502                             _ => unreachable!("cast adt {} -> {}", from_ty, to_ty),
 503                         }
 504
 505                         // FIXME avoid forcing to stack
 506                         let place =
 507                             CPlace::for_addr(operand.force_stack(fx), operand.layout());
 508                         let discr = trans_get_discriminant(fx, place, fx.layout_of(to_ty));
 509                         lval.write_cvalue(fx, discr);
 510                     } else {
 511                         let from_clif_ty = fx.clif_type(from_ty).unwrap();
 512                         let to_clif_ty = fx.clif_type(to_ty).unwrap();
 513                         let from = operand.load_scalar(fx);
 514
 515                         let signed = match from_ty.sty {
 516                             ty::Ref(..) | ty::RawPtr(..) | ty::FnPtr(..) | ty::Char | ty::Uint(..) | ty::Bool => false,
 517                             ty::Int(..) => true,
 518                             ty::Float(..) => false, // `signed` is unused for floats
 519                             _ => panic!("{}", from_ty),
 520                         };
 521
 522                         let res = if from_clif_ty.is_int() && to_clif_ty.is_int() {
 523                             // int-like -> int-like
 524                             crate::common::clif_intcast(
 525                                 fx,
 526                                 from,
 527                                 to_clif_ty,
 528                                 signed,
 529                             )
 530                         } else if from_clif_ty.is_int() && to_clif_ty.is_float() {
 531                             // int-like -> float
 532                             if signed {
 533                                 fx.bcx.ins().fcvt_from_sint(to_clif_ty, from)
 534                             } else {
 535                                 fx.bcx.ins().fcvt_from_uint(to_clif_ty, from)
 536                             }
 537                         } else if from_clif_ty.is_float() && to_clif_ty.is_int() {
 538                             // float -> int-like
 539                             let from = operand.load_scalar(fx);
 540                             if signed {
 541                                 fx.bcx.ins().fcvt_to_sint_sat(to_clif_ty, from)
 542                             } else {
 543                                 fx.bcx.ins().fcvt_to_uint_sat(to_clif_ty, from)
 544                             }
 545                         } else if from_clif_ty.is_float() && to_clif_ty.is_float() {
 546                             // float -> float
 547                             match (from_clif_ty, to_clif_ty) {
 548                                 (types::F32, types::F64) => {
 549                                     fx.bcx.ins().fpromote(types::F64, from)
 550                                 }
 551                                 (types::F64, types::F32) => {
 552                                     fx.bcx.ins().fdemote(types::F32, from)
 553                                 }
 554                                 _ => from,
 555                             }
 556                         } else {
 557                             unimpl!("rval misc {:?} {:?}", from_ty, to_ty)
 558                         };
 559                         lval.write_cvalue(fx, CValue::by_val(res, dest_layout));
 560                     }
 561                 }
 562                 Rvalue::Cast(CastKind::Pointer(PointerCast::ClosureFnPointer(_)), operand, _ty) => {
 563                     let operand = trans_operand(fx, operand);
 564                     match operand.layout().ty.sty {
 565                         ty::Closure(def_id, substs) => {
 566                             let instance = Instance::resolve_closure(
 567                                 fx.tcx,
 568                                 def_id,
 569                                 substs,
 570                                 ty::ClosureKind::FnOnce,
 571                             );
 572                             let func_ref = fx.get_function_ref(instance);
 573                             let func_addr = fx.bcx.ins().func_addr(fx.pointer_type, func_ref);
 574                             lval.write_cvalue(fx, CValue::by_val(func_addr, lval.layout()));
 575                         }
 576                         _ => {
 577                             bug!("{} cannot be cast to a fn ptr", operand.layout().ty)
 578                         }
 579                     }
 580                 }
 581                 Rvalue::Cast(CastKind::Pointer(PointerCast::Unsize), operand, _ty) => {
 582                     let operand = trans_operand(fx, operand);
 583                     operand.unsize_value(fx, lval);
 584                 }
 585                 Rvalue::Discriminant(place) => {
 586                     let place = trans_place(fx, place);
 587                     let discr = trans_get_discriminant(fx, place, dest_layout);
 588                     lval.write_cvalue(fx, discr);
 589                 }
 590                 Rvalue::Repeat(operand, times) => {
 591                     let operand = trans_operand(fx, operand);
 592                     for i in 0..*times {
 593                         let index = fx.bcx.ins().iconst(fx.pointer_type, i as i64);
 594                         let to = lval.place_index(fx, index);
 595                         to.write_cvalue(fx, operand);
 596                     }
 597                 }
 598                 Rvalue::Len(place) => {
 599                     let place = trans_place(fx, place);
 600                     let usize_layout = fx.layout_of(fx.tcx.types.usize);
 601                     let len = codegen_array_len(fx, place);
 602                     lval.write_cvalue(fx, CValue::by_val(len, usize_layout));
 603                 }
 604                 Rvalue::NullaryOp(NullOp::Box, content_ty) => {
 605                     use rustc::middle::lang_items::ExchangeMallocFnLangItem;
 606
 607                     let usize_type = fx.clif_type(fx.tcx.types.usize).unwrap();
 608                     let layout = fx.layout_of(content_ty);
 609                     let llsize = fx.bcx.ins().iconst(usize_type, layout.size.bytes() as i64);
 610                     let llalign = fx
 611                         .bcx
 612                         .ins()
 613                         .iconst(usize_type, layout.align.abi.bytes() as i64);
 614                     let box_layout = fx.layout_of(fx.tcx.mk_box(content_ty));
 615
 616                     // Allocate space:
 617                     let def_id = match fx.tcx.lang_items().require(ExchangeMallocFnLangItem) {
 618                         Ok(id) => id,
 619                         Err(s) => {
 620                             fx.tcx
 621                                 .sess
 622                                 .fatal(&format!("allocation of `{}` {}", box_layout.ty, s));
 623                         }
 624                     };
 625                     let instance = ty::Instance::mono(fx.tcx, def_id);
 626                     let func_ref = fx.get_function_ref(instance);
 627                     let call = fx.bcx.ins().call(func_ref, &[llsize, llalign]);
 628                     let ptr = fx.bcx.inst_results(call)[0];
 629                     lval.write_cvalue(fx, CValue::by_val(ptr, box_layout));
 630                 }
 631                 Rvalue::NullaryOp(NullOp::SizeOf, ty) => {
 632                     assert!(lval
 633                         .layout()
 634                         .ty
 635                         .is_sized(fx.tcx.at(DUMMY_SP), ParamEnv::reveal_all()));
 636                     let ty_size = fx.layout_of(ty).size.bytes();
 637                     let val = CValue::const_val(fx, fx.tcx.types.usize, ty_size as i64);
 638                     lval.write_cvalue(fx, val);
 639                 }
 640                 Rvalue::Aggregate(kind, operands) => match **kind {
 641                     AggregateKind::Array(_ty) => {
 642                         for (i, operand) in operands.into_iter().enumerate() {
 643                             let operand = trans_operand(fx, operand);
 644                             let index = fx.bcx.ins().iconst(fx.pointer_type, i as i64);
 645                             let to = lval.place_index(fx, index);
 646                             to.write_cvalue(fx, operand);
 647                         }
 648                     }
 649                     _ => unimpl!("shouldn't exist at trans {:?}", rval),
 650                 },
 651             }
 652         }
 653         StatementKind::StorageLive(_)
 654         | StatementKind::StorageDead(_)
 655         | StatementKind::Nop
 656         | StatementKind::FakeRead(..)
 657         | StatementKind::Retag { .. }
 658         | StatementKind::AscribeUserType(..) => {}
 659
 660         StatementKind::InlineAsm { .. } => unimpl!("Inline assembly is not supported"),
 661     }
 662 }
 663
 664 fn codegen_array_len<'a, 'tcx: 'a>(
 665     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 666     place: CPlace<'tcx>,
 667 ) -> Value {
 668     match place.layout().ty.sty {
 669         ty::Array(_elem_ty, len) => {
 670             let len = crate::constant::force_eval_const(fx, len).unwrap_usize(fx.tcx) as i64;
 671             fx.bcx.ins().iconst(fx.pointer_type, len)
 672         }
 673         ty::Slice(_elem_ty) => place
 674             .to_addr_maybe_unsized(fx)
 675             .1
 676             .expect("Length metadata for slice place"),
 677         _ => bug!("Rvalue::Len({:?})", place),
 678     }
 679 }
 680
 681 pub fn trans_get_discriminant<'a, 'tcx: 'a>(
 682     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 683     place: CPlace<'tcx>,
 684     dest_layout: TyLayout<'tcx>,
 685 ) -> CValue<'tcx> {
 686     let layout = place.layout();
 687
 688     if layout.abi == layout::Abi::Uninhabited {
 689         return trap_unreachable_ret_value(fx, dest_layout, "[panic] Tried to get discriminant for uninhabited type.");
 690     }
 691
 692     let (discr_scalar, discr_index, discr_kind) = match &layout.variants {
 693         layout::Variants::Single { index } => {
 694             let discr_val = layout
 695                 .ty
 696                 .ty_adt_def()
 697                 .map_or(index.as_u32() as u128, |def| {
 698                     def.discriminant_for_variant(fx.tcx, *index).val
 699                 });
 700             return CValue::const_val(fx, dest_layout.ty, discr_val as u64 as i64);
 701         }
 702         layout::Variants::Multiple { discr, discr_index, discr_kind, variants: _ } => {
 703             (discr, *discr_index, discr_kind)
 704         }
 705     };
 706
 707     let discr = place.place_field(fx, mir::Field::new(discr_index)).to_cvalue(fx);
 708     let discr_ty = discr.layout().ty;
 709     let lldiscr = discr.load_scalar(fx);
 710     match discr_kind {
 711         layout::DiscriminantKind::Tag => {
 712             let signed = match discr_scalar.value {
 713                 layout::Int(_, signed) => signed,
 714                 _ => false,
 715             };
 716             let val = clif_intcast(fx, lldiscr, fx.clif_type(dest_layout.ty).unwrap(), signed);
 717             return CValue::by_val(val, dest_layout);
 718         }
 719         layout::DiscriminantKind::Niche {
 720             dataful_variant,
 721             ref niche_variants,
 722             niche_start,
 723         } => {
 724             let niche_llty = fx.clif_type(discr_ty).unwrap();
 725             let dest_clif_ty = fx.clif_type(dest_layout.ty).unwrap();
 726             if niche_variants.start() == niche_variants.end() {
 727                 let b = fx
 728                     .bcx
 729                     .ins()
 730                     .icmp_imm(IntCC::Equal, lldiscr, *niche_start as u64 as i64);
 731                 let if_true = fx
 732                     .bcx
 733                     .ins()
 734                     .iconst(dest_clif_ty, niche_variants.start().as_u32() as i64);
 735                 let if_false = fx
 736                     .bcx
 737                     .ins()
 738                     .iconst(dest_clif_ty, dataful_variant.as_u32() as i64);
 739                 let val = fx.bcx.ins().select(b, if_true, if_false);
 740                 return CValue::by_val(val, dest_layout);
 741             } else {
 742                 // Rebase from niche values to discriminant values.
 743                 let delta = niche_start.wrapping_sub(niche_variants.start().as_u32() as u128);
 744                 let delta = fx.bcx.ins().iconst(niche_llty, delta as u64 as i64);
 745                 let lldiscr = fx.bcx.ins().isub(lldiscr, delta);
 746                 let b = fx.bcx.ins().icmp_imm(
 747                     IntCC::UnsignedLessThanOrEqual,
 748                     lldiscr,
 749                     niche_variants.end().as_u32() as i64,
 750                 );
 751                 let if_true =
 752                     clif_intcast(fx, lldiscr, fx.clif_type(dest_layout.ty).unwrap(), false);
 753                 let if_false = fx
 754                     .bcx
 755                     .ins()
 756                     .iconst(dest_clif_ty, dataful_variant.as_u32() as i64);
 757                 let val = fx.bcx.ins().select(b, if_true, if_false);
 758                 return CValue::by_val(val, dest_layout);
 759             }
 760         }
 761     }
 762 }
 763
 764 macro_rules! binop_match {
 765     (@single $fx:expr, $bug_fmt:expr, $var:expr, $signed:expr, $lhs:expr, $rhs:expr, $ret_ty:expr, bug) => {
 766         bug!("binop {} on {} lhs: {:?} rhs: {:?}", stringify!($var), $bug_fmt, $lhs, $rhs)
 767     };
 768     (@single $fx:expr, $bug_fmt:expr, $var:expr, $signed:expr, $lhs:expr, $rhs:expr, $ret_ty:expr, icmp($cc:ident)) => {{
 769         assert_eq!($fx.tcx.types.bool, $ret_ty);
 770         let ret_layout = $fx.layout_of($ret_ty);
 771
 772         let b = $fx.bcx.ins().icmp(IntCC::$cc, $lhs, $rhs);
 773         CValue::by_val($fx.bcx.ins().bint(types::I8, b), ret_layout)
 774     }};
 775     (@single $fx:expr, $bug_fmt:expr, $var:expr, $signed:expr, $lhs:expr, $rhs:expr, $ret_ty:expr, fcmp($cc:ident)) => {{
 776         assert_eq!($fx.tcx.types.bool, $ret_ty);
 777         let ret_layout = $fx.layout_of($ret_ty);
 778         let b = $fx.bcx.ins().fcmp(FloatCC::$cc, $lhs, $rhs);
 779         CValue::by_val($fx.bcx.ins().bint(types::I8, b), ret_layout)
 780     }};
 781     (@single $fx:expr, $bug_fmt:expr, $var:expr, $signed:expr, $lhs:expr, $rhs:expr, $ret_ty:expr, custom(|| $body:expr)) => {{
 782         $body
 783     }};
 784     (@single $fx:expr, $bug_fmt:expr, $var:expr, $signed:expr, $lhs:expr, $rhs:expr, $ret_ty:expr, $name:ident) => {{
 785         let ret_layout = $fx.layout_of($ret_ty);
 786         CValue::by_val($fx.bcx.ins().$name($lhs, $rhs), ret_layout)
 787     }};
 788     (
 789         $fx:expr, $bin_op:expr, $signed:expr, $lhs:expr, $rhs:expr, $ret_ty:expr, $bug_fmt:expr;
 790         $(
 791             $var:ident ($sign:pat) $name:tt $( ( $($next:tt)* ) )? ;
 792         )*
 793     ) => {{
 794         let lhs = $lhs.load_scalar($fx);
 795         let rhs = $rhs.load_scalar($fx);
 796         match ($bin_op, $signed) {
 797             $(
 798                 (BinOp::$var, $sign) => binop_match!(@single $fx, $bug_fmt, $var, $signed, lhs, rhs, $ret_ty, $name $( ( $($next)* ) )?),
 799             )*
 800         }
 801     }}
 802 }
 803
 804 fn trans_bool_binop<'a, 'tcx: 'a>(
 805     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 806     bin_op: BinOp,
 807     lhs: CValue<'tcx>,
 808     rhs: CValue<'tcx>,
 809     ty: Ty<'tcx>,
 810 ) -> CValue<'tcx> {
 811     let res = binop_match! {
 812         fx, bin_op, false, lhs, rhs, ty, "bool";
 813         Add (_) bug;
 814         Sub (_) bug;
 815         Mul (_) bug;
 816         Div (_) bug;
 817         Rem (_) bug;
 818         BitXor (_) bxor;
 819         BitAnd (_) band;
 820         BitOr (_) bor;
 821         Shl (_) bug;
 822         Shr (_) bug;
 823
 824         Eq (_) icmp(Equal);
 825         Lt (_) icmp(UnsignedLessThan);
 826         Le (_) icmp(UnsignedLessThanOrEqual);
 827         Ne (_) icmp(NotEqual);
 828         Ge (_) icmp(UnsignedGreaterThanOrEqual);
 829         Gt (_) icmp(UnsignedGreaterThan);
 830
 831         Offset (_) bug;
 832     };
 833
 834     res
 835 }
 836
 837 pub fn trans_int_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     out_ty: Ty<'tcx>,
 843     signed: bool,
 844 ) -> CValue<'tcx> {
 845     if bin_op != BinOp::Shl && bin_op != BinOp::Shr {
 846         assert_eq!(
 847             lhs.layout().ty,
 848             rhs.layout().ty,
 849             "int binop requires lhs and rhs of same type"
 850         );
 851     }
 852     binop_match! {
 853         fx, bin_op, signed, lhs, rhs, out_ty, "int/uint";
 854         Add (_) iadd;
 855         Sub (_) isub;
 856         Mul (_) imul;
 857         Div (false) udiv;
 858         Div (true) sdiv;
 859         Rem (false) urem;
 860         Rem (true) srem;
 861         BitXor (_) bxor;
 862         BitAnd (_) band;
 863         BitOr (_) bor;
 864         Shl (_) ishl;
 865         Shr (false) ushr;
 866         Shr (true) sshr;
 867
 868         Eq (_) icmp(Equal);
 869         Lt (false) icmp(UnsignedLessThan);
 870         Lt (true) icmp(SignedLessThan);
 871         Le (false) icmp(UnsignedLessThanOrEqual);
 872         Le (true) icmp(SignedLessThanOrEqual);
 873         Ne (_) icmp(NotEqual);
 874         Ge (false) icmp(UnsignedGreaterThanOrEqual);
 875         Ge (true) icmp(SignedGreaterThanOrEqual);
 876         Gt (false) icmp(UnsignedGreaterThan);
 877         Gt (true) icmp(SignedGreaterThan);
 878
 879         Offset (_) bug;
 880     }
 881 }
 882
 883 pub fn trans_checked_int_binop<'a, 'tcx: 'a>(
 884     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 885     bin_op: BinOp,
 886     in_lhs: CValue<'tcx>,
 887     in_rhs: CValue<'tcx>,
 888     out_ty: Ty<'tcx>,
 889     signed: bool,
 890 ) -> CValue<'tcx> {
 891     if bin_op != BinOp::Shl && bin_op != BinOp::Shr {
 892         assert_eq!(
 893             in_lhs.layout().ty,
 894             in_rhs.layout().ty,
 895             "checked int binop requires lhs and rhs of same type"
 896         );
 897     }
 898
 899     let lhs = in_lhs.load_scalar(fx);
 900     let rhs = in_rhs.load_scalar(fx);
 901     let res = match bin_op {
 902         BinOp::Add => fx.bcx.ins().iadd(lhs, rhs),
 903         BinOp::Sub => fx.bcx.ins().isub(lhs, rhs),
 904         BinOp::Mul => fx.bcx.ins().imul(lhs, rhs),
 905         BinOp::Shl => fx.bcx.ins().ishl(lhs, rhs),
 906         BinOp::Shr => {
 907             if !signed {
 908                 fx.bcx.ins().ushr(lhs, rhs)
 909             } else {
 910                 fx.bcx.ins().sshr(lhs, rhs)
 911             }
 912         }
 913         _ => bug!(
 914             "binop {:?} on checked int/uint lhs: {:?} rhs: {:?}",
 915             bin_op,
 916             in_lhs,
 917             in_rhs
 918         ),
 919     };
 920
 921     // TODO: check for overflow
 922     let has_overflow = fx.bcx.ins().iconst(types::I8, 0);
 923
 924     let out_place = CPlace::new_stack_slot(fx, out_ty);
 925     let out_layout = out_place.layout();
 926     out_place.write_cvalue(fx, CValue::by_val_pair(res, has_overflow, out_layout));
 927
 928     out_place.to_cvalue(fx)
 929 }
 930
 931 fn trans_float_binop<'a, 'tcx: 'a>(
 932     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 933     bin_op: BinOp,
 934     lhs: CValue<'tcx>,
 935     rhs: CValue<'tcx>,
 936     ty: Ty<'tcx>,
 937 ) -> CValue<'tcx> {
 938     let res = binop_match! {
 939         fx, bin_op, false, lhs, rhs, ty, "float";
 940         Add (_) fadd;
 941         Sub (_) fsub;
 942         Mul (_) fmul;
 943         Div (_) fdiv;
 944         Rem (_) custom(|| {
 945             assert_eq!(lhs.layout().ty, ty);
 946             assert_eq!(rhs.layout().ty, ty);
 947             match ty.sty {
 948                 ty::Float(FloatTy::F32) => fx.easy_call("fmodf", &[lhs, rhs], ty),
 949                 ty::Float(FloatTy::F64) => fx.easy_call("fmod", &[lhs, rhs], ty),
 950                 _ => bug!(),
 951             }
 952         });
 953         BitXor (_) bxor;
 954         BitAnd (_) band;
 955         BitOr (_) bor;
 956         Shl (_) bug;
 957         Shr (_) bug;
 958
 959         Eq (_) fcmp(Equal);
 960         Lt (_) fcmp(LessThan);
 961         Le (_) fcmp(LessThanOrEqual);
 962         Ne (_) fcmp(NotEqual);
 963         Ge (_) fcmp(GreaterThanOrEqual);
 964         Gt (_) fcmp(GreaterThan);
 965
 966         Offset (_) bug;
 967     };
 968
 969     res
 970 }
 971
 972 fn trans_char_binop<'a, 'tcx: 'a>(
 973     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
 974     bin_op: BinOp,
 975     lhs: CValue<'tcx>,
 976     rhs: CValue<'tcx>,
 977     ty: Ty<'tcx>,
 978 ) -> CValue<'tcx> {
 979     let res = binop_match! {
 980         fx, bin_op, false, lhs, rhs, ty, "char";
 981         Add (_) bug;
 982         Sub (_) bug;
 983         Mul (_) bug;
 984         Div (_) bug;
 985         Rem (_) bug;
 986         BitXor (_) bug;
 987         BitAnd (_) bug;
 988         BitOr (_) bug;
 989         Shl (_) bug;
 990         Shr (_) bug;
 991
 992         Eq (_) icmp(Equal);
 993         Lt (_) icmp(UnsignedLessThan);
 994         Le (_) icmp(UnsignedLessThanOrEqual);
 995         Ne (_) icmp(NotEqual);
 996         Ge (_) icmp(UnsignedGreaterThanOrEqual);
 997         Gt (_) icmp(UnsignedGreaterThan);
 998
 999         Offset (_) bug;
1000     };
1001
1002     res
1003 }
1004
1005 fn trans_ptr_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     ret_ty: Ty<'tcx>,
1011 ) -> CValue<'tcx> {
1012     let not_fat = match lhs.layout().ty.sty {
1013         ty::RawPtr(TypeAndMut { ty, mutbl: _ }) => {
1014             ty.is_sized(fx.tcx.at(DUMMY_SP), ParamEnv::reveal_all())
1015         }
1016         ty::FnPtr(..) => true,
1017         _ => bug!("trans_ptr_binop on non ptr"),
1018     };
1019     if not_fat {
1020         if let BinOp::Offset = bin_op {
1021             let (base, offset) = (lhs, rhs.load_scalar(fx));
1022             let pointee_ty = base.layout().ty.builtin_deref(true).unwrap().ty;
1023             let pointee_size = fx.layout_of(pointee_ty).size.bytes();
1024             let ptr_diff = fx.bcx.ins().imul_imm(offset, pointee_size as i64);
1025             let base_val = base.load_scalar(fx);
1026             let res = fx.bcx.ins().iadd(base_val, ptr_diff);
1027             return CValue::by_val(res, base.layout());
1028         }
1029
1030         binop_match! {
1031             fx, bin_op, false, lhs, rhs, ret_ty, "ptr";
1032             Add (_) bug;
1033             Sub (_) bug;
1034             Mul (_) bug;
1035             Div (_) bug;
1036             Rem (_) bug;
1037             BitXor (_) bug;
1038             BitAnd (_) bug;
1039             BitOr (_) bug;
1040             Shl (_) bug;
1041             Shr (_) bug;
1042
1043             Eq (_) icmp(Equal);
1044             Lt (_) icmp(UnsignedLessThan);
1045             Le (_) icmp(UnsignedLessThanOrEqual);
1046             Ne (_) icmp(NotEqual);
1047             Ge (_) icmp(UnsignedGreaterThanOrEqual);
1048             Gt (_) icmp(UnsignedGreaterThan);
1049
1050             Offset (_) bug; // Handled above
1051         }
1052     } else {
1053         let (lhs_ptr, lhs_extra) = lhs.load_scalar_pair(fx);
1054         let (rhs_ptr, rhs_extra) = rhs.load_scalar_pair(fx);
1055
1056         let res = match bin_op {
1057             BinOp::Eq => {
1058                 let ptr_eq = fx.bcx.ins().icmp(IntCC::Equal, lhs_ptr, rhs_ptr);
1059                 let extra_eq = fx.bcx.ins().icmp(IntCC::Equal, lhs_extra, rhs_extra);
1060                 fx.bcx.ins().band(ptr_eq, extra_eq)
1061             }
1062             BinOp::Ne => {
1063                 let ptr_ne = fx.bcx.ins().icmp(IntCC::NotEqual, lhs_ptr, rhs_ptr);
1064                 let extra_ne = fx.bcx.ins().icmp(IntCC::NotEqual, lhs_extra, rhs_extra);
1065                 fx.bcx.ins().bor(ptr_ne, extra_ne)
1066             }
1067             BinOp::Lt | BinOp::Le | BinOp::Ge | BinOp::Gt => {
1068                 let ptr_eq = fx.bcx.ins().icmp(IntCC::Equal, lhs_ptr, rhs_ptr);
1069
1070                 let ptr_cmp = fx.bcx.ins().icmp(match bin_op {
1071                     BinOp::Lt => IntCC::UnsignedLessThan,
1072                     BinOp::Le => IntCC::UnsignedLessThanOrEqual,
1073                     BinOp::Ge => IntCC::UnsignedGreaterThanOrEqual,
1074                     BinOp::Gt => IntCC::UnsignedGreaterThan,
1075                     _ => unreachable!(),
1076                 }, lhs_ptr, rhs_ptr);
1077
1078                 let extra_cmp = fx.bcx.ins().icmp(match bin_op {
1079                     BinOp::Lt => IntCC::UnsignedLessThan,
1080                     BinOp::Le => IntCC::UnsignedLessThanOrEqual,
1081                     BinOp::Ge => IntCC::UnsignedGreaterThanOrEqual,
1082                     BinOp::Gt => IntCC::UnsignedGreaterThan,
1083                     _ => unreachable!(),
1084                 }, lhs_extra, rhs_extra);
1085
1086                 fx.bcx.ins().select(ptr_eq, extra_cmp, ptr_cmp)
1087             }
1088             _ => panic!("bin_op {:?} on ptr", bin_op),
1089         };
1090
1091         assert_eq!(fx.tcx.types.bool, ret_ty);
1092         let ret_layout = fx.layout_of(ret_ty);
1093         CValue::by_val(fx.bcx.ins().bint(types::I8, res), ret_layout)
1094     }
1095 }
1096
1097 pub fn trans_place<'a, 'tcx: 'a>(
1098     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
1099     place: &Place<'tcx>,
1100 ) -> CPlace<'tcx> {
1101     match place {
1102         Place::Base(base) => match base {
1103             PlaceBase::Local(local) => fx.get_local_place(*local),
1104             PlaceBase::Static(static_) => match static_.kind {
1105                 StaticKind::Static(def_id) => {
1106                     crate::constant::codegen_static_ref(fx, def_id, static_.ty)
1107                 }
1108                 StaticKind::Promoted(promoted) => {
1109                     crate::constant::trans_promoted(fx, promoted, static_.ty)
1110                 }
1111             }
1112         }
1113         Place::Projection(projection) => {
1114             let base = trans_place(fx, &projection.base);
1115             match projection.elem {
1116                 ProjectionElem::Deref => base.place_deref(fx),
1117                 ProjectionElem::Field(field, _ty) => base.place_field(fx, field),
1118                 ProjectionElem::Index(local) => {
1119                     let index = fx.get_local_place(local).to_cvalue(fx).load_scalar(fx);
1120                     base.place_index(fx, index)
1121                 }
1122                 ProjectionElem::ConstantIndex {
1123                     offset,
1124                     min_length: _,
1125                     from_end,
1126                 } => {
1127                     let index = if !from_end {
1128                         fx.bcx.ins().iconst(fx.pointer_type, offset as i64)
1129                     } else {
1130                         let len = codegen_array_len(fx, base);
1131                         fx.bcx.ins().iadd_imm(len, -(offset as i64))
1132                     };
1133                     base.place_index(fx, index)
1134                 }
1135                 ProjectionElem::Subslice { from, to } => {
1136                     // These indices are generated by slice patterns.
1137                     // slice[from:-to] in Python terms.
1138
1139                     match base.layout().ty.sty {
1140                         ty::Array(elem_ty, len) => {
1141                             let elem_layout = fx.layout_of(elem_ty);
1142                             let ptr = base.to_addr(fx);
1143                             let len = crate::constant::force_eval_const(fx, len).unwrap_usize(fx.tcx);
1144                             CPlace::for_addr(
1145                                 fx.bcx.ins().iadd_imm(ptr, elem_layout.size.bytes() as i64 * from as i64),
1146                                 fx.layout_of(fx.tcx.mk_array(elem_ty, len - from as u64 - to as u64)),
1147                             )
1148                         }
1149                         ty::Slice(elem_ty) => {
1150                             let elem_layout = fx.layout_of(elem_ty);
1151                             let (ptr, len) = base.to_addr_maybe_unsized(fx);
1152                             let len = len.unwrap();
1153                             CPlace::for_addr_with_extra(
1154                                 fx.bcx.ins().iadd_imm(ptr, elem_layout.size.bytes() as i64 * from as i64),
1155                                 fx.bcx.ins().iadd_imm(len, -(from as i64 + to as i64)),
1156                                 base.layout(),
1157                             )
1158                         }
1159                         _ => unreachable!(),
1160                     }
1161                 }
1162                 ProjectionElem::Downcast(_adt_def, variant) => base.downcast_variant(fx, variant),
1163             }
1164         }
1165     }
1166 }
1167
1168 pub fn trans_operand<'a, 'tcx>(
1169     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
1170     operand: &Operand<'tcx>,
1171 ) -> CValue<'tcx> {
1172     match operand {
1173         Operand::Move(place) | Operand::Copy(place) => {
1174             let cplace = trans_place(fx, place);
1175             cplace.to_cvalue(fx)
1176         }
1177         Operand::Constant(const_) => crate::constant::trans_constant(fx, const_),
1178     }
1179 }