src/base.rs

   1 use rustc_middle::ty::adjustment::PointerCast;
   2 use rustc_index::vec::IndexVec;
   3
   4 use crate::prelude::*;
   5
   6 pub(crate) fn trans_fn<'tcx, B: Backend + 'static>(
   7     cx: &mut crate::CodegenCx<'tcx, B>,
   8     instance: Instance<'tcx>,
   9     linkage: Linkage,
  10 ) {
  11     let tcx = cx.tcx;
  12
  13     let mir = tcx.instance_mir(instance.def);
  14
  15     // Declare function
  16     let (name, sig) = get_function_name_and_sig(tcx, cx.module.isa().triple(), instance, false);
  17     let func_id = cx.module.declare_function(&name, linkage, &sig).unwrap();
  18
  19     // Make FunctionBuilder
  20     let context = &mut cx.cached_context;
  21     context.clear();
  22     context.func.name = ExternalName::user(0, func_id.as_u32());
  23     context.func.signature = sig;
  24     context.func.collect_debug_info();
  25     let mut func_ctx = FunctionBuilderContext::new();
  26     let mut bcx = FunctionBuilder::new(&mut context.func, &mut func_ctx);
  27
  28     // Predefine blocks
  29     let start_block = bcx.create_block();
  30     let block_map: IndexVec<BasicBlock, Block> = (0..mir.basic_blocks().len()).map(|_| bcx.create_block()).collect();
  31
  32     // Make FunctionCx
  33     let pointer_type = cx.module.target_config().pointer_type();
  34     let clif_comments = crate::pretty_clif::CommentWriter::new(tcx, instance);
  35
  36     let mut fx = FunctionCx {
  37         tcx,
  38         module: &mut cx.module,
  39         pointer_type,
  40
  41         instance,
  42         mir,
  43
  44         bcx,
  45         block_map,
  46         local_map: FxHashMap::with_capacity_and_hasher(mir.local_decls.len(), Default::default()),
  47         caller_location: None, // set by `codegen_fn_prelude`
  48         cold_blocks: EntitySet::new(),
  49
  50         clif_comments,
  51         constants_cx: &mut cx.constants_cx,
  52         vtables: &mut cx.vtables,
  53         source_info_set: indexmap::IndexSet::new(),
  54     };
  55
  56     let arg_uninhabited = fx.mir.args_iter().any(|arg| fx.layout_of(fx.monomorphize(&fx.mir.local_decls[arg].ty)).abi.is_uninhabited());
  57
  58     if arg_uninhabited {
  59         fx.bcx.append_block_params_for_function_params(fx.block_map[START_BLOCK]);
  60         fx.bcx.switch_to_block(fx.block_map[START_BLOCK]);
  61         crate::trap::trap_unreachable(&mut fx, "function has uninhabited argument");
  62     } else {
  63         tcx.sess.time("codegen clif ir", || {
  64             tcx.sess.time("codegen prelude", || crate::abi::codegen_fn_prelude(&mut fx, start_block, true));
  65             codegen_fn_content(&mut fx);
  66         });
  67     }
  68
  69     // Recover all necessary data from fx, before accessing func will prevent future access to it.
  70     let instance = fx.instance;
  71     let mut clif_comments = fx.clif_comments;
  72     let source_info_set = fx.source_info_set;
  73     let local_map = fx.local_map;
  74     let cold_blocks = fx.cold_blocks;
  75
  76     crate::pretty_clif::write_clif_file(cx.tcx, "unopt", instance, &context.func, &clif_comments, None);
  77
  78     // Verify function
  79     verify_func(tcx, &clif_comments, &context.func);
  80
  81     // Perform rust specific optimizations
  82     tcx.sess.time("optimize clif ir", || {
  83         crate::optimize::optimize_function(tcx, instance, context, &cold_blocks, &mut clif_comments);
  84     });
  85
  86     // If the return block is not reachable, then the SSA builder may have inserted a `iconst.i128`
  87     // instruction, which doesn't have an encoding.
  88     context.compute_cfg();
  89     context.compute_domtree();
  90     context.eliminate_unreachable_code(cx.module.isa()).unwrap();
  91
  92     // Define function
  93     let module = &mut cx.module;
  94     tcx.sess.time(
  95         "define function",
  96         || module.define_function(
  97             func_id,
  98             context,
  99             &mut cranelift_codegen::binemit::NullTrapSink {},
 100         ).unwrap(),
 101     );
 102
 103     // Write optimized function to file for debugging
 104     {
 105         let value_ranges = context
 106             .build_value_labels_ranges(cx.module.isa())
 107             .expect("value location ranges");
 108
 109         crate::pretty_clif::write_clif_file(
 110             cx.tcx,
 111             "opt",
 112             instance,
 113             &context.func,
 114             &clif_comments,
 115             Some(&value_ranges),
 116         );
 117     }
 118
 119     // Define debuginfo for function
 120     let isa = cx.module.isa();
 121     let debug_context = &mut cx.debug_context;
 122     let unwind_context = &mut cx.unwind_context;
 123     tcx.sess.time("generate debug info", || {
 124         if let Some(debug_context) = debug_context {
 125             debug_context.define_function(instance, func_id, &name, isa, context, &source_info_set, local_map);
 126         }
 127         unwind_context.add_function(func_id, &context, isa);
 128     });
 129
 130     // Clear context to make it usable for the next function
 131     context.clear();
 132 }
 133
 134 pub(crate) fn verify_func(tcx: TyCtxt<'_>, writer: &crate::pretty_clif::CommentWriter, func: &Function) {
 135     tcx.sess.time("verify clif ir", || {
 136         let flags = settings::Flags::new(settings::builder());
 137         match ::cranelift_codegen::verify_function(&func, &flags) {
 138             Ok(_) => {}
 139             Err(err) => {
 140                 tcx.sess.err(&format!("{:?}", err));
 141                 let pretty_error = ::cranelift_codegen::print_errors::pretty_verifier_error(
 142                     &func,
 143                     None,
 144                     Some(Box::new(writer)),
 145                     err,
 146                 );
 147                 tcx.sess
 148                     .fatal(&format!("cranelift verify error:\n{}", pretty_error));
 149             }
 150         }
 151     });
 152 }
 153
 154 fn codegen_fn_content(fx: &mut FunctionCx<'_, '_, impl Backend>) {
 155     for (bb, bb_data) in fx.mir.basic_blocks().iter_enumerated() {
 156         let block = fx.get_block(bb);
 157         fx.bcx.switch_to_block(block);
 158
 159         if bb_data.is_cleanup {
 160             // Unwinding after panicking is not supported
 161             continue;
 162
 163             // FIXME once unwinding is supported uncomment next lines
 164             // // Unwinding is unlikely to happen, so mark cleanup block's as cold.
 165             // fx.cold_blocks.insert(block);
 166         }
 167
 168         fx.bcx.ins().nop();
 169         for stmt in &bb_data.statements {
 170             fx.set_debug_loc(stmt.source_info);
 171             trans_stmt(fx, block, stmt);
 172         }
 173
 174         #[cfg(debug_assertions)]
 175         {
 176             let mut terminator_head = "\n".to_string();
 177             bb_data
 178                 .terminator()
 179                 .kind
 180                 .fmt_head(&mut terminator_head)
 181                 .unwrap();
 182             let inst = fx.bcx.func.layout.last_inst(block).unwrap();
 183             fx.add_comment(inst, terminator_head);
 184         }
 185
 186         fx.set_debug_loc(bb_data.terminator().source_info);
 187
 188         match &bb_data.terminator().kind {
 189             TerminatorKind::Goto { target } => {
 190                 if let TerminatorKind::Return = fx.mir[*target].terminator().kind {
 191                     let mut can_immediately_return = true;
 192                     for stmt in &fx.mir[*target].statements {
 193                         if let StatementKind::StorageDead(_) = stmt.kind {
 194                         } else {
 195                             // FIXME Can sometimes happen, see rust-lang/rust#70531
 196                             can_immediately_return = false;
 197                             break;
 198                         }
 199                     }
 200
 201                     if can_immediately_return {
 202                         crate::abi::codegen_return(fx);
 203                         continue;
 204                     }
 205                 }
 206
 207                 let block = fx.get_block(*target);
 208                 fx.bcx.ins().jump(block, &[]);
 209             }
 210             TerminatorKind::Return => {
 211                 crate::abi::codegen_return(fx);
 212             }
 213             TerminatorKind::Assert {
 214                 cond,
 215                 expected,
 216                 msg,
 217                 target,
 218                 cleanup: _,
 219             } => {
 220                 if !fx.tcx.sess.overflow_checks() {
 221                     if let mir::AssertKind::OverflowNeg = *msg {
 222                         let target = fx.get_block(*target);
 223                         fx.bcx.ins().jump(target, &[]);
 224                         continue;
 225                     }
 226                 }
 227                 let cond = trans_operand(fx, cond).load_scalar(fx);
 228
 229                 let target = fx.get_block(*target);
 230                 let failure = fx.bcx.create_block();
 231                 fx.cold_blocks.insert(failure);
 232
 233                 if *expected {
 234                     fx.bcx.ins().brz(cond, failure, &[]);
 235                 } else {
 236                     fx.bcx.ins().brnz(cond, failure, &[]);
 237                 };
 238                 fx.bcx.ins().jump(target, &[]);
 239
 240                 fx.bcx.switch_to_block(failure);
 241
 242                 let location = fx.get_caller_location(bb_data.terminator().source_info.span).load_scalar(fx);
 243
 244                 let args;
 245                 let lang_item = match msg {
 246                     AssertKind::BoundsCheck { ref len, ref index } => {
 247                         let len = trans_operand(fx, len).load_scalar(fx);
 248                         let index = trans_operand(fx, index).load_scalar(fx);
 249                         args = [index, len, location];
 250                         rustc_hir::lang_items::PanicBoundsCheckFnLangItem
 251                     }
 252                     _ => {
 253                         let msg_str = msg.description();
 254                         let msg_ptr = fx.anonymous_str("assert", msg_str);
 255                         let msg_len = fx.bcx.ins().iconst(fx.pointer_type, i64::try_from(msg_str.len()).unwrap());
 256                         args = [msg_ptr, msg_len, location];
 257                         rustc_hir::lang_items::PanicFnLangItem
 258                     }
 259                 };
 260
 261                 let def_id = fx.tcx.lang_items().require(lang_item).unwrap_or_else(|s| {
 262                     fx.tcx.sess.span_fatal(bb_data.terminator().source_info.span, &s)
 263                 });
 264
 265                 let instance = Instance::mono(fx.tcx, def_id);
 266                 let symbol_name = fx.tcx.symbol_name(instance).name.as_str();
 267
 268                 fx.lib_call(&*symbol_name, vec![fx.pointer_type, fx.pointer_type, fx.pointer_type], vec![], &args);
 269
 270                 crate::trap::trap_unreachable(fx, "panic lang item returned");
 271             }
 272
 273             TerminatorKind::SwitchInt {
 274                 discr,
 275                 switch_ty: _,
 276                 values,
 277                 targets,
 278             } => {
 279                 let discr = trans_operand(fx, discr).load_scalar(fx);
 280                 let mut switch = ::cranelift_frontend::Switch::new();
 281                 for (i, value) in values.iter().enumerate() {
 282                     let block = fx.get_block(targets[i]);
 283                     switch.set_entry(*value as u64, block);
 284                 }
 285                 let otherwise_block = fx.get_block(targets[targets.len() - 1]);
 286                 switch.emit(&mut fx.bcx, discr, otherwise_block);
 287             }
 288             TerminatorKind::Call {
 289                 func,
 290                 args,
 291                 destination,
 292                 fn_span,
 293                 cleanup: _,
 294                 from_hir_call: _,
 295             } => {
 296                 fx.tcx.sess.time("codegen call", || crate::abi::codegen_terminator_call(
 297                     fx,
 298                     *fn_span,
 299                     block,
 300                     func,
 301                     args,
 302                     *destination,
 303                 ));
 304             }
 305             TerminatorKind::InlineAsm {
 306                 template,
 307                 operands,
 308                 options: _,
 309                 destination,
 310                 line_spans: _,
 311             } => {
 312                 match template {
 313                     &[] => {
 314                         assert_eq!(operands, &[]);
 315                         match *destination {
 316                             Some(destination) => {
 317                                 let destination_block = fx.get_block(destination);
 318                                 fx.bcx.ins().jump(destination_block, &[]);
 319                             }
 320                             None => bug!(),
 321                         }
 322
 323                         // Black box
 324                     }
 325                     _ => unimpl_fatal!(fx.tcx, bb_data.terminator().source_info.span, "Inline assembly is not supported"),
 326                 }
 327             }
 328             TerminatorKind::Resume | TerminatorKind::Abort => {
 329                 trap_unreachable(fx, "[corruption] Unwinding bb reached.");
 330             }
 331             TerminatorKind::Unreachable => {
 332                 trap_unreachable(fx, "[corruption] Hit unreachable code.");
 333             }
 334             TerminatorKind::Yield { .. }
 335             | TerminatorKind::FalseEdge { .. }
 336             | TerminatorKind::FalseUnwind { .. }
 337             | TerminatorKind::DropAndReplace { .. }
 338             | TerminatorKind::GeneratorDrop => {
 339                 bug!("shouldn't exist at trans {:?}", bb_data.terminator());
 340             }
 341             TerminatorKind::Drop {
 342                 location,
 343                 target,
 344                 unwind: _,
 345             } => {
 346                 let drop_place = trans_place(fx, *location);
 347                 crate::abi::codegen_drop(fx, bb_data.terminator().source_info.span, drop_place);
 348
 349                 let target_block = fx.get_block(*target);
 350                 fx.bcx.ins().jump(target_block, &[]);
 351             }
 352         };
 353     }
 354
 355     fx.bcx.seal_all_blocks();
 356     fx.bcx.finalize();
 357 }
 358
 359 fn trans_stmt<'tcx>(
 360     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
 361     #[allow(unused_variables)]
 362     cur_block: Block,
 363     stmt: &Statement<'tcx>,
 364 ) {
 365     let _print_guard = PrintOnPanic(|| format!("stmt {:?}", stmt));
 366
 367     fx.set_debug_loc(stmt.source_info);
 368
 369     #[cfg(false_debug_assertions)]
 370     match &stmt.kind {
 371         StatementKind::StorageLive(..) | StatementKind::StorageDead(..) => {} // Those are not very useful
 372         _ => {
 373             let inst = fx.bcx.func.layout.last_inst(cur_block).unwrap();
 374             fx.add_comment(inst, format!("{:?}", stmt));
 375         }
 376     }
 377
 378     match &stmt.kind {
 379         StatementKind::SetDiscriminant {
 380             place,
 381             variant_index,
 382         } => {
 383             let place = trans_place(fx, **place);
 384             crate::discriminant::codegen_set_discriminant(fx, place, *variant_index);
 385         }
 386         StatementKind::Assign(to_place_and_rval) => {
 387             let lval = trans_place(fx, to_place_and_rval.0);
 388             let dest_layout = lval.layout();
 389             match &to_place_and_rval.1 {
 390                 Rvalue::Use(operand) => {
 391                     let val = trans_operand(fx, operand);
 392                     lval.write_cvalue(fx, val);
 393                 }
 394                 Rvalue::Ref(_, _, place) | Rvalue::AddressOf(_, place) => {
 395                     let place = trans_place(fx, *place);
 396                     place.write_place_ref(fx, lval);
 397                 }
 398                 Rvalue::ThreadLocalRef(def_id) => {
 399                     let val = crate::constant::codegen_tls_ref(fx, *def_id, lval.layout());
 400                     lval.write_cvalue(fx, val);
 401                 }
 402                 Rvalue::BinaryOp(bin_op, lhs, rhs) => {
 403                     let lhs = trans_operand(fx, lhs);
 404                     let rhs = trans_operand(fx, rhs);
 405
 406                     let res = crate::num::codegen_binop(fx, *bin_op, lhs, rhs);
 407                     lval.write_cvalue(fx, res);
 408                 }
 409                 Rvalue::CheckedBinaryOp(bin_op, lhs, rhs) => {
 410                     let lhs = trans_operand(fx, lhs);
 411                     let rhs = trans_operand(fx, rhs);
 412
 413                     let res = if !fx.tcx.sess.overflow_checks() {
 414                         let val =
 415                             crate::num::trans_int_binop(fx, *bin_op, lhs, rhs).load_scalar(fx);
 416                         let is_overflow = fx.bcx.ins().iconst(types::I8, 0);
 417                         CValue::by_val_pair(val, is_overflow, lval.layout())
 418                     } else {
 419                         crate::num::trans_checked_int_binop(fx, *bin_op, lhs, rhs)
 420                     };
 421
 422                     lval.write_cvalue(fx, res);
 423                 }
 424                 Rvalue::UnaryOp(un_op, operand) => {
 425                     let operand = trans_operand(fx, operand);
 426                     let layout = operand.layout();
 427                     let val = operand.load_scalar(fx);
 428                     let res = match un_op {
 429                         UnOp::Not => {
 430                             match layout.ty.kind {
 431                                 ty::Bool => {
 432                                     let res = fx.bcx.ins().icmp_imm(IntCC::Equal, val, 0);
 433                                     CValue::by_val(fx.bcx.ins().bint(types::I8, res), layout)
 434                                 }
 435                                 ty::Uint(_) | ty::Int(_) => {
 436                                     CValue::by_val(fx.bcx.ins().bnot(val), layout)
 437                                 }
 438                                 _ => unreachable!("un op Not for {:?}", layout.ty),
 439                             }
 440                         }
 441                         UnOp::Neg => match layout.ty.kind {
 442                             ty::Int(IntTy::I128) => {
 443                                 // FIXME remove this case once ineg.i128 works
 444                                 let zero = CValue::const_val(fx, layout, 0);
 445                                 crate::num::trans_int_binop(fx, BinOp::Sub, zero, operand)
 446                             }
 447                             ty::Int(_) => {
 448                                 CValue::by_val(fx.bcx.ins().ineg(val), layout)
 449                             }
 450                             ty::Float(_) => {
 451                                 CValue::by_val(fx.bcx.ins().fneg(val), layout)
 452                             }
 453                             _ => unreachable!("un op Neg for {:?}", layout.ty),
 454                         },
 455                     };
 456                     lval.write_cvalue(fx, res);
 457                 }
 458                 Rvalue::Cast(CastKind::Pointer(PointerCast::ReifyFnPointer), operand, to_ty) => {
 459                     let from_ty = fx.monomorphize(&operand.ty(&fx.mir.local_decls, fx.tcx));
 460                     let to_layout = fx.layout_of(fx.monomorphize(to_ty));
 461                     match from_ty.kind {
 462                         ty::FnDef(def_id, substs) => {
 463                             let func_ref = fx.get_function_ref(
 464                                 Instance::resolve_for_fn_ptr(fx.tcx, ParamEnv::reveal_all(), def_id, substs)
 465                                     .unwrap(),
 466                             );
 467                             let func_addr = fx.bcx.ins().func_addr(fx.pointer_type, func_ref);
 468                             lval.write_cvalue(fx, CValue::by_val(func_addr, to_layout));
 469                         }
 470                         _ => bug!("Trying to ReifyFnPointer on non FnDef {:?}", from_ty),
 471                     }
 472                 }
 473                 Rvalue::Cast(CastKind::Pointer(PointerCast::UnsafeFnPointer), operand, to_ty)
 474                 | Rvalue::Cast(CastKind::Pointer(PointerCast::MutToConstPointer), operand, to_ty)
 475                 | Rvalue::Cast(CastKind::Pointer(PointerCast::ArrayToPointer), operand, to_ty) => {
 476                     let to_layout = fx.layout_of(fx.monomorphize(to_ty));
 477                     let operand = trans_operand(fx, operand);
 478                     lval.write_cvalue(fx, operand.cast_pointer_to(to_layout));
 479                 }
 480                 Rvalue::Cast(CastKind::Misc, operand, to_ty) => {
 481                     let operand = trans_operand(fx, operand);
 482                     let from_ty = operand.layout().ty;
 483                     let to_ty = fx.monomorphize(to_ty);
 484
 485                     fn is_fat_ptr<'tcx>(
 486                         fx: &FunctionCx<'_, 'tcx, impl Backend>,
 487                         ty: Ty<'tcx>,
 488                     ) -> bool {
 489                         ty.builtin_deref(true)
 490                             .map(
 491                                 |ty::TypeAndMut {
 492                                      ty: pointee_ty,
 493                                      mutbl: _,
 494                                  }| has_ptr_meta(fx.tcx, pointee_ty),
 495                             )
 496                             .unwrap_or(false)
 497                     }
 498
 499                     if is_fat_ptr(fx, from_ty) {
 500                         if is_fat_ptr(fx, to_ty) {
 501                             // fat-ptr -> fat-ptr
 502                             lval.write_cvalue(fx, operand.cast_pointer_to(dest_layout));
 503                         } else {
 504                             // fat-ptr -> thin-ptr
 505                             let (ptr, _extra) = operand.load_scalar_pair(fx);
 506                             lval.write_cvalue(fx, CValue::by_val(ptr, dest_layout))
 507                         }
 508                     } else if let ty::Adt(adt_def, _substs) = from_ty.kind {
 509                         // enum -> discriminant value
 510                         assert!(adt_def.is_enum());
 511                         match to_ty.kind {
 512                             ty::Uint(_) | ty::Int(_) => {}
 513                             _ => unreachable!("cast adt {} -> {}", from_ty, to_ty),
 514                         }
 515
 516                         let discr = crate::discriminant::codegen_get_discriminant(
 517                             fx,
 518                             operand,
 519                             fx.layout_of(to_ty),
 520                         );
 521                         lval.write_cvalue(fx, discr);
 522                     } else {
 523                         let to_clif_ty = fx.clif_type(to_ty).unwrap();
 524                         let from = operand.load_scalar(fx);
 525
 526                         let res = clif_int_or_float_cast(
 527                             fx,
 528                             from,
 529                             type_sign(from_ty),
 530                             to_clif_ty,
 531                             type_sign(to_ty),
 532                         );
 533                         lval.write_cvalue(fx, CValue::by_val(res, dest_layout));
 534                     }
 535                 }
 536                 Rvalue::Cast(CastKind::Pointer(PointerCast::ClosureFnPointer(_)), operand, _to_ty) => {
 537                     let operand = trans_operand(fx, operand);
 538                     match operand.layout().ty.kind {
 539                         ty::Closure(def_id, substs) => {
 540                             let instance = Instance::resolve_closure(
 541                                 fx.tcx,
 542                                 def_id,
 543                                 substs,
 544                                 ty::ClosureKind::FnOnce,
 545                             );
 546                             let func_ref = fx.get_function_ref(instance);
 547                             let func_addr = fx.bcx.ins().func_addr(fx.pointer_type, func_ref);
 548                             lval.write_cvalue(fx, CValue::by_val(func_addr, lval.layout()));
 549                         }
 550                         _ => bug!("{} cannot be cast to a fn ptr", operand.layout().ty),
 551                     }
 552                 }
 553                 Rvalue::Cast(CastKind::Pointer(PointerCast::Unsize), operand, _to_ty) => {
 554                     let operand = trans_operand(fx, operand);
 555                     operand.unsize_value(fx, lval);
 556                 }
 557                 Rvalue::Discriminant(place) => {
 558                     let place = trans_place(fx, *place);
 559                     let value = place.to_cvalue(fx);
 560                     let discr =
 561                         crate::discriminant::codegen_get_discriminant(fx, value, dest_layout);
 562                     lval.write_cvalue(fx, discr);
 563                 }
 564                 Rvalue::Repeat(operand, times) => {
 565                     let operand = trans_operand(fx, operand);
 566                     let times = fx
 567                         .monomorphize(times)
 568                         .eval(fx.tcx, ParamEnv::reveal_all())
 569                         .val
 570                         .try_to_bits(fx.tcx.data_layout.pointer_size)
 571                         .unwrap();
 572                     for i in 0..times {
 573                         let index = fx.bcx.ins().iconst(fx.pointer_type, i as i64);
 574                         let to = lval.place_index(fx, index);
 575                         to.write_cvalue(fx, operand);
 576                     }
 577                 }
 578                 Rvalue::Len(place) => {
 579                     let place = trans_place(fx, *place);
 580                     let usize_layout = fx.layout_of(fx.tcx.types.usize);
 581                     let len = codegen_array_len(fx, place);
 582                     lval.write_cvalue(fx, CValue::by_val(len, usize_layout));
 583                 }
 584                 Rvalue::NullaryOp(NullOp::Box, content_ty) => {
 585                     use rustc_hir::lang_items::ExchangeMallocFnLangItem;
 586
 587                     let usize_type = fx.clif_type(fx.tcx.types.usize).unwrap();
 588                     let content_ty = fx.monomorphize(content_ty);
 589                     let layout = fx.layout_of(content_ty);
 590                     let llsize = fx.bcx.ins().iconst(usize_type, layout.size.bytes() as i64);
 591                     let llalign = fx
 592                         .bcx
 593                         .ins()
 594                         .iconst(usize_type, layout.align.abi.bytes() as i64);
 595                     let box_layout = fx.layout_of(fx.tcx.mk_box(content_ty));
 596
 597                     // Allocate space:
 598                     let def_id = match fx.tcx.lang_items().require(ExchangeMallocFnLangItem) {
 599                         Ok(id) => id,
 600                         Err(s) => {
 601                             fx.tcx
 602                                 .sess
 603                                 .fatal(&format!("allocation of `{}` {}", box_layout.ty, s));
 604                         }
 605                     };
 606                     let instance = ty::Instance::mono(fx.tcx, def_id);
 607                     let func_ref = fx.get_function_ref(instance);
 608                     let call = fx.bcx.ins().call(func_ref, &[llsize, llalign]);
 609                     let ptr = fx.bcx.inst_results(call)[0];
 610                     lval.write_cvalue(fx, CValue::by_val(ptr, box_layout));
 611                 }
 612                 Rvalue::NullaryOp(NullOp::SizeOf, ty) => {
 613                     assert!(lval
 614                         .layout()
 615                         .ty
 616                         .is_sized(fx.tcx.at(stmt.source_info.span), ParamEnv::reveal_all()));
 617                     let ty_size = fx.layout_of(fx.monomorphize(ty)).size.bytes();
 618                     let val = CValue::const_val(fx, fx.layout_of(fx.tcx.types.usize), ty_size.into());
 619                     lval.write_cvalue(fx, val);
 620                 }
 621                 Rvalue::Aggregate(kind, operands) => match **kind {
 622                     AggregateKind::Array(_ty) => {
 623                         for (i, operand) in operands.into_iter().enumerate() {
 624                             let operand = trans_operand(fx, operand);
 625                             let index = fx.bcx.ins().iconst(fx.pointer_type, i as i64);
 626                             let to = lval.place_index(fx, index);
 627                             to.write_cvalue(fx, operand);
 628                         }
 629                     }
 630                     _ => unreachable!("shouldn't exist at trans {:?}", to_place_and_rval.1),
 631                 },
 632             }
 633         }
 634         StatementKind::StorageLive(_)
 635         | StatementKind::StorageDead(_)
 636         | StatementKind::Nop
 637         | StatementKind::FakeRead(..)
 638         | StatementKind::Retag { .. }
 639         | StatementKind::AscribeUserType(..) => {}
 640
 641         StatementKind::LlvmInlineAsm(asm) => {
 642             use rustc_span::symbol::Symbol;
 643             let LlvmInlineAsm {
 644                 asm,
 645                 outputs: _,
 646                 inputs: _,
 647             } = &**asm;
 648             let rustc_hir::LlvmInlineAsmInner {
 649                 asm: asm_code, // Name
 650                 outputs,       // Vec<Name>
 651                 inputs,        // Vec<Name>
 652                 clobbers,      // Vec<Name>
 653                 volatile,      // bool
 654                 alignstack,    // bool
 655                 dialect: _,    // rustc_ast::ast::AsmDialect
 656                 asm_str_style: _,
 657             } = asm;
 658             match &*asm_code.as_str() {
 659                 cpuid if cpuid.contains("cpuid") => {
 660                     crate::trap::trap_unimplemented(
 661                         fx,
 662                         "__cpuid_count arch intrinsic is not supported",
 663                     );
 664                 }
 665                 "xgetbv" => {
 666                     assert_eq!(inputs, &[Symbol::intern("{ecx}")]);
 667
 668                     assert_eq!(outputs.len(), 2);
 669                     for (i, c) in (&["={eax}", "={edx}"]).iter().enumerate() {
 670                         assert_eq!(&outputs[i].constraint.as_str(), c);
 671                         assert!(!outputs[i].is_rw);
 672                         assert!(!outputs[i].is_indirect);
 673                     }
 674
 675                     assert_eq!(clobbers, &[]);
 676
 677                     assert!(!volatile);
 678                     assert!(!alignstack);
 679
 680                     crate::trap::trap_unimplemented(fx, "_xgetbv arch intrinsic is not supported");
 681                 }
 682                 // ___chkstk, ___chkstk_ms and __alloca are only used on Windows
 683                 _ if fx.tcx.symbol_name(fx.instance).name.as_str().starts_with("___chkstk") => {
 684                     crate::trap::trap_unimplemented(fx, "Stack probes are not supported");
 685                 }
 686                 _ if fx.tcx.symbol_name(fx.instance).name.as_str() == "__alloca" => {
 687                     crate::trap::trap_unimplemented(fx, "Alloca is not supported");
 688                 }
 689                 // Used in sys::windows::abort_internal
 690                 "int $$0x29" => {
 691                     crate::trap::trap_unimplemented(fx, "Windows abort");
 692                 }
 693                 _ => unimpl_fatal!(fx.tcx, stmt.source_info.span, "Inline assembly is not supported"),
 694             }
 695         }
 696     }
 697 }
 698
 699 fn codegen_array_len<'tcx>(
 700     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
 701     place: CPlace<'tcx>,
 702 ) -> Value {
 703     match place.layout().ty.kind {
 704         ty::Array(_elem_ty, len) => {
 705             let len = fx.monomorphize(&len)
 706                 .eval(fx.tcx, ParamEnv::reveal_all())
 707                 .eval_usize(fx.tcx, ParamEnv::reveal_all()) as i64;
 708             fx.bcx.ins().iconst(fx.pointer_type, len)
 709         }
 710         ty::Slice(_elem_ty) => place
 711             .to_ptr_maybe_unsized()
 712             .1
 713             .expect("Length metadata for slice place"),
 714         _ => bug!("Rvalue::Len({:?})", place),
 715     }
 716 }
 717
 718 pub(crate) fn trans_place<'tcx>(
 719     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
 720     place: Place<'tcx>,
 721 ) -> CPlace<'tcx> {
 722     let mut cplace = fx.get_local_place(place.local);
 723
 724     for elem in place.projection {
 725         match elem {
 726             PlaceElem::Deref => {
 727                 cplace = cplace.place_deref(fx);
 728             }
 729             PlaceElem::Field(field, _ty) => {
 730                 cplace = cplace.place_field(fx, field);
 731             }
 732             PlaceElem::Index(local) => {
 733                 let index = fx.get_local_place(local).to_cvalue(fx).load_scalar(fx);
 734                 cplace = cplace.place_index(fx, index);
 735             }
 736             PlaceElem::ConstantIndex {
 737                 offset,
 738                 min_length: _,
 739                 from_end,
 740             } => {
 741                 let index = if !from_end {
 742                     fx.bcx.ins().iconst(fx.pointer_type, offset as i64)
 743                 } else {
 744                     let len = codegen_array_len(fx, cplace);
 745                     fx.bcx.ins().iadd_imm(len, -(offset as i64))
 746                 };
 747                 cplace = cplace.place_index(fx, index);
 748             }
 749             PlaceElem::Subslice { from, to, from_end } => {
 750                 // These indices are generated by slice patterns.
 751                 // slice[from:-to] in Python terms.
 752
 753                 match cplace.layout().ty.kind {
 754                     ty::Array(elem_ty, _len) => {
 755                         assert!(!from_end, "array subslices are never `from_end`");
 756                         let elem_layout = fx.layout_of(elem_ty);
 757                         let ptr = cplace.to_ptr();
 758                         cplace = CPlace::for_ptr(
 759                             ptr.offset_i64(fx, elem_layout.size.bytes() as i64 * from as i64),
 760                             fx.layout_of(fx.tcx.mk_array(elem_ty, to as u64 - from as u64)),
 761                         );
 762                     }
 763                     ty::Slice(elem_ty) => {
 764                         assert!(from_end, "slice subslices should be `from_end`");
 765                         let elem_layout = fx.layout_of(elem_ty);
 766                         let (ptr, len) = cplace.to_ptr_maybe_unsized();
 767                         let len = len.unwrap();
 768                         cplace = CPlace::for_ptr_with_extra(
 769                             ptr.offset_i64(fx, elem_layout.size.bytes() as i64 * from as i64),
 770                             fx.bcx.ins().iadd_imm(len, -(from as i64 + to as i64)),
 771                             cplace.layout(),
 772                         );
 773                     }
 774                     _ => unreachable!(),
 775                 }
 776             }
 777             PlaceElem::Downcast(_adt_def, variant) => {
 778                 cplace = cplace.downcast_variant(fx, variant);
 779             }
 780         }
 781     }
 782
 783     cplace
 784 }
 785
 786 pub(crate) fn trans_operand<'tcx>(
 787     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
 788     operand: &Operand<'tcx>,
 789 ) -> CValue<'tcx> {
 790     match operand {
 791         Operand::Move(place) | Operand::Copy(place) => {
 792             let cplace = trans_place(fx, *place);
 793             cplace.to_cvalue(fx)
 794         }
 795         Operand::Constant(const_) => crate::constant::trans_constant(fx, const_),
 796     }
 797 }