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