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