src/base.rs

   1 use rustc::ty::adjustment::PointerCast;
   2 use rustc_index::vec::IndexVec;
   3
   4 use crate::prelude::*;
   5
   6 pub 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 ebb's
  33     let start_ebb = bcx.create_ebb();
  34     let ebb_map: IndexVec<BasicBlock, Ebb> = (0..mir.basic_blocks().len()).map(|_| bcx.create_ebb()).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         ebb_map,
  50         local_map: HashMap::new(),
  51
  52         clif_comments,
  53         constants_cx: &mut cx.constants_cx,
  54         vtables: &mut cx.vtables,
  55         source_info_set: indexmap::IndexSet::new(),
  56     };
  57
  58     if fx.mir.args_iter().any(|arg| fx.layout_of(fx.monomorphize(&fx.mir.local_decls[arg].ty)).abi.is_uninhabited()) {
  59         let entry_block = fx.bcx.create_ebb();
  60         fx.bcx.append_ebb_params_for_function_params(entry_block);
  61         fx.bcx.switch_to_block(entry_block);
  62         crate::trap::trap_unreachable(&mut fx, "function has uninhabited argument");
  63     } else {
  64         crate::abi::codegen_fn_prelude(&mut fx, start_ebb);
  65         codegen_fn_content(&mut fx);
  66     }
  67
  68     // Recover all necessary data from fx, before accessing func will prevent future access to it.
  69     let instance = fx.instance;
  70     let mut clif_comments = fx.clif_comments;
  71     let source_info_set = fx.source_info_set;
  72     let local_map = fx.local_map;
  73
  74     #[cfg(debug_assertions)]
  75     crate::pretty_clif::write_clif_file(cx.tcx, "unopt", instance, &context.func, &clif_comments, None);
  76
  77     // Verify function
  78     verify_func(tcx, &clif_comments, &context.func);
  79
  80     // Perform rust specific optimizations
  81     crate::optimize::optimize_function(cx.tcx, instance, context, &mut clif_comments);
  82
  83     // Define function
  84     cx.module.define_function(func_id, context).unwrap();
  85
  86     // Write optimized function to file for debugging
  87     #[cfg(debug_assertions)]
  88     {
  89         let value_ranges = context
  90             .build_value_labels_ranges(cx.module.isa())
  91             .expect("value location ranges");
  92
  93         crate::pretty_clif::write_clif_file(
  94             cx.tcx,
  95             "opt",
  96             instance,
  97             &context.func,
  98             &clif_comments,
  99             Some(&value_ranges),
 100         );
 101     }
 102
 103     // Define debuginfo for function
 104     let isa = cx.module.isa();
 105     debug_context
 106         .as_mut()
 107         .map(|x| x.define(context, isa, &source_info_set, local_map));
 108
 109     // Clear context to make it usable for the next function
 110     context.clear();
 111 }
 112
 113 pub fn verify_func(tcx: TyCtxt, writer: &crate::pretty_clif::CommentWriter, func: &Function) {
 114     let flags = settings::Flags::new(settings::builder());
 115     match ::cranelift_codegen::verify_function(&func, &flags) {
 116         Ok(_) => {}
 117         Err(err) => {
 118             tcx.sess.err(&format!("{:?}", err));
 119             let pretty_error = ::cranelift_codegen::print_errors::pretty_verifier_error(
 120                 &func,
 121                 None,
 122                 Some(Box::new(writer)),
 123                 err,
 124             );
 125             tcx.sess
 126                 .fatal(&format!("cranelift verify error:\n{}", pretty_error));
 127         }
 128     }
 129 }
 130
 131 fn codegen_fn_content(fx: &mut FunctionCx<'_, '_, impl Backend>) {
 132     for (bb, bb_data) in fx.mir.basic_blocks().iter_enumerated() {
 133         if bb_data.is_cleanup {
 134             // Unwinding after panicking is not supported
 135             continue;
 136         }
 137
 138         let ebb = fx.get_ebb(bb);
 139         fx.bcx.switch_to_block(ebb);
 140
 141         fx.bcx.ins().nop();
 142         for stmt in &bb_data.statements {
 143             fx.set_debug_loc(stmt.source_info);
 144             trans_stmt(fx, ebb, stmt);
 145         }
 146
 147         #[cfg(debug_assertions)]
 148         {
 149             let mut terminator_head = "\n".to_string();
 150             bb_data
 151                 .terminator()
 152                 .kind
 153                 .fmt_head(&mut terminator_head)
 154                 .unwrap();
 155             let inst = fx.bcx.func.layout.last_inst(ebb).unwrap();
 156             fx.add_comment(inst, terminator_head);
 157         }
 158
 159         fx.set_debug_loc(bb_data.terminator().source_info);
 160
 161         match &bb_data.terminator().kind {
 162             TerminatorKind::Goto { target } => {
 163                 let ebb = fx.get_ebb(*target);
 164                 fx.bcx.ins().jump(ebb, &[]);
 165             }
 166             TerminatorKind::Return => {
 167                 crate::abi::codegen_return(fx);
 168             }
 169             TerminatorKind::Assert {
 170                 cond,
 171                 expected,
 172                 msg,
 173                 target,
 174                 cleanup: _,
 175             } => {
 176                 if !fx.tcx.sess.overflow_checks() {
 177                     if let mir::interpret::PanicInfo::OverflowNeg = *msg {
 178                         let target = fx.get_ebb(*target);
 179                         fx.bcx.ins().jump(target, &[]);
 180                         continue;
 181                     }
 182                 }
 183                 let cond = trans_operand(fx, cond).load_scalar(fx);
 184                 let target = fx.get_ebb(*target);
 185                 let failure = fx.bcx.create_ebb();
 186                 if *expected {
 187                     fx.bcx.ins().brz(cond, failure, &[]);
 188                 } else {
 189                     fx.bcx.ins().brnz(cond, failure, &[]);
 190                 };
 191                 fx.bcx.ins().jump(target, &[]);
 192
 193                 // FIXME insert bb after all other bb's to reduce the amount of jumps in the common
 194                 // case and improve code locality.
 195                 fx.bcx.switch_to_block(failure);
 196                 trap_panic(
 197                     fx,
 198                     format!(
 199                         "[panic] Assert {:?} at {:?} failed.",
 200                         msg,
 201                         bb_data.terminator().source_info.span
 202                     ),
 203                 );
 204             }
 205
 206             TerminatorKind::SwitchInt {
 207                 discr,
 208                 switch_ty: _,
 209                 values,
 210                 targets,
 211             } => {
 212                 let discr = trans_operand(fx, discr).load_scalar(fx);
 213                 let mut switch = ::cranelift_frontend::Switch::new();
 214                 for (i, value) in values.iter().enumerate() {
 215                     let ebb = fx.get_ebb(targets[i]);
 216                     switch.set_entry(*value as u64, ebb);
 217                 }
 218                 let otherwise_ebb = fx.get_ebb(targets[targets.len() - 1]);
 219                 switch.emit(&mut fx.bcx, discr, otherwise_ebb);
 220             }
 221             TerminatorKind::Call {
 222                 func,
 223                 args,
 224                 destination,
 225                 cleanup: _,
 226                 from_hir_call: _,
 227             } => {
 228                 crate::abi::codegen_terminator_call(
 229                     fx,
 230                     func,
 231                     args,
 232                     destination,
 233                     bb_data.terminator().source_info.span,
 234                 );
 235             }
 236             TerminatorKind::Resume | TerminatorKind::Abort => {
 237                 trap_unreachable(fx, "[corruption] Unwinding bb reached.");
 238             }
 239             TerminatorKind::Unreachable => {
 240                 trap_unreachable(fx, "[corruption] Hit unreachable code.");
 241             }
 242             TerminatorKind::Yield { .. }
 243             | TerminatorKind::FalseEdges { .. }
 244             | TerminatorKind::FalseUnwind { .. }
 245             | TerminatorKind::DropAndReplace { .. }
 246             | TerminatorKind::GeneratorDrop => {
 247                 bug!("shouldn't exist at trans {:?}", bb_data.terminator());
 248             }
 249             TerminatorKind::Drop {
 250                 location,
 251                 target,
 252                 unwind: _,
 253             } => {
 254                 let drop_place = trans_place(fx, location);
 255                 crate::abi::codegen_drop(fx, drop_place);
 256
 257                 let target_ebb = fx.get_ebb(*target);
 258                 fx.bcx.ins().jump(target_ebb, &[]);
 259             }
 260         };
 261     }
 262
 263     fx.bcx.seal_all_blocks();
 264     fx.bcx.finalize();
 265 }
 266
 267 fn trans_stmt<'tcx>(
 268     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
 269     cur_ebb: Ebb,
 270     stmt: &Statement<'tcx>,
 271 ) {
 272     let _print_guard = PrintOnPanic(|| format!("stmt {:?}", stmt));
 273
 274     fx.set_debug_loc(stmt.source_info);
 275
 276     #[cfg(debug_assertions)]
 277     match &stmt.kind {
 278         StatementKind::StorageLive(..) | StatementKind::StorageDead(..) => {} // Those are not very useful
 279         _ => {
 280             let inst = fx.bcx.func.layout.last_inst(cur_ebb).unwrap();
 281             fx.add_comment(inst, format!("{:?}", stmt));
 282         }
 283     }
 284
 285     match &stmt.kind {
 286         StatementKind::SetDiscriminant {
 287             place,
 288             variant_index,
 289         } => {
 290             let place = trans_place(fx, place);
 291             crate::discriminant::codegen_set_discriminant(fx, place, *variant_index);
 292         }
 293         StatementKind::Assign(to_place_and_rval) => {
 294             let lval = trans_place(fx, &to_place_and_rval.0);
 295             let dest_layout = lval.layout();
 296             match &to_place_and_rval.1 {
 297                 Rvalue::Use(operand) => {
 298                     let val = trans_operand(fx, operand);
 299                     lval.write_cvalue(fx, val);
 300                 }
 301                 Rvalue::Ref(_, _, place) | Rvalue::AddressOf(_, place) => {
 302                     let place = trans_place(fx, place);
 303                     place.write_place_ref(fx, lval);
 304                 }
 305                 Rvalue::BinaryOp(bin_op, lhs, rhs) => {
 306                     let lhs = trans_operand(fx, lhs);
 307                     let rhs = trans_operand(fx, rhs);
 308
 309                     let res = crate::num::codegen_binop(fx, *bin_op, lhs, rhs);
 310                     lval.write_cvalue(fx, res);
 311                 }
 312                 Rvalue::CheckedBinaryOp(bin_op, lhs, rhs) => {
 313                     let lhs = trans_operand(fx, lhs);
 314                     let rhs = trans_operand(fx, rhs);
 315
 316                     let res = if !fx.tcx.sess.overflow_checks() {
 317                         let val =
 318                             crate::num::trans_int_binop(fx, *bin_op, lhs, rhs).load_scalar(fx);
 319                         let is_overflow = fx.bcx.ins().iconst(types::I8, 0);
 320                         CValue::by_val_pair(val, is_overflow, lval.layout())
 321                     } else {
 322                         crate::num::trans_checked_int_binop(fx, *bin_op, lhs, rhs)
 323                     };
 324
 325                     lval.write_cvalue(fx, res);
 326                 }
 327                 Rvalue::UnaryOp(un_op, operand) => {
 328                     let operand = trans_operand(fx, operand);
 329                     let layout = operand.layout();
 330                     let val = operand.load_scalar(fx);
 331                     let res = match un_op {
 332                         UnOp::Not => {
 333                             match layout.ty.kind {
 334                                 ty::Bool => {
 335                                     let val = fx.bcx.ins().uextend(types::I32, val); // WORKAROUND for CraneStation/cranelift#466
 336                                     let res = fx.bcx.ins().icmp_imm(IntCC::Equal, val, 0);
 337                                     CValue::by_val(fx.bcx.ins().bint(types::I8, res), layout)
 338                                 }
 339                                 ty::Uint(_) | ty::Int(_) => {
 340                                     CValue::by_val(fx.bcx.ins().bnot(val), layout)
 341                                 }
 342                                 _ => unimplemented!("un op Not for {:?}", layout.ty),
 343                             }
 344                         }
 345                         UnOp::Neg => match layout.ty.kind {
 346                             ty::Int(_) => {
 347                                 let zero = CValue::const_val(fx, layout.ty, 0);
 348                                 crate::num::trans_int_binop(fx, BinOp::Sub, zero, operand)
 349                             }
 350                             ty::Float(_) => {
 351                                 CValue::by_val(fx.bcx.ins().fneg(val), layout)
 352                             }
 353                             _ => unimplemented!("un op Neg for {:?}", layout.ty),
 354                         },
 355                     };
 356                     lval.write_cvalue(fx, res);
 357                 }
 358                 Rvalue::Cast(CastKind::Pointer(PointerCast::ReifyFnPointer), operand, to_ty) => {
 359                     let from_ty = fx.monomorphize(&operand.ty(&fx.mir.local_decls, fx.tcx));
 360                     let to_layout = fx.layout_of(fx.monomorphize(to_ty));
 361                     match from_ty.kind {
 362                         ty::FnDef(def_id, substs) => {
 363                             let func_ref = fx.get_function_ref(
 364                                 Instance::resolve(fx.tcx, ParamEnv::reveal_all(), def_id, substs)
 365                                     .unwrap(),
 366                             );
 367                             let func_addr = fx.bcx.ins().func_addr(fx.pointer_type, func_ref);
 368                             lval.write_cvalue(fx, CValue::by_val(func_addr, to_layout));
 369                         }
 370                         _ => bug!("Trying to ReifyFnPointer on non FnDef {:?}", from_ty),
 371                     }
 372                 }
 373                 Rvalue::Cast(CastKind::Pointer(PointerCast::UnsafeFnPointer), operand, to_ty)
 374                 | Rvalue::Cast(CastKind::Pointer(PointerCast::MutToConstPointer), operand, to_ty)
 375                 | Rvalue::Cast(CastKind::Pointer(PointerCast::ArrayToPointer), operand, to_ty) => {
 376                     let to_layout = fx.layout_of(fx.monomorphize(to_ty));
 377                     let operand = trans_operand(fx, operand);
 378                     lval.write_cvalue(fx, operand.unchecked_cast_to(to_layout));
 379                 }
 380                 Rvalue::Cast(CastKind::Misc, operand, to_ty) => {
 381                     let operand = trans_operand(fx, operand);
 382                     let from_ty = operand.layout().ty;
 383                     let to_ty = fx.monomorphize(to_ty);
 384
 385                     fn is_fat_ptr<'tcx>(
 386                         fx: &FunctionCx<'_, 'tcx, impl Backend>,
 387                         ty: Ty<'tcx>,
 388                     ) -> bool {
 389                         ty.builtin_deref(true)
 390                             .map(
 391                                 |ty::TypeAndMut {
 392                                      ty: pointee_ty,
 393                                      mutbl: _,
 394                                  }| has_ptr_meta(fx.tcx, pointee_ty),
 395                             )
 396                             .unwrap_or(false)
 397                     }
 398
 399                     if is_fat_ptr(fx, from_ty) {
 400                         if is_fat_ptr(fx, to_ty) {
 401                             // fat-ptr -> fat-ptr
 402                             lval.write_cvalue(fx, operand.unchecked_cast_to(dest_layout));
 403                         } else {
 404                             // fat-ptr -> thin-ptr
 405                             let (ptr, _extra) = operand.load_scalar_pair(fx);
 406                             lval.write_cvalue(fx, CValue::by_val(ptr, dest_layout))
 407                         }
 408                     } else if let ty::Adt(adt_def, _substs) = from_ty.kind {
 409                         // enum -> discriminant value
 410                         assert!(adt_def.is_enum());
 411                         match to_ty.kind {
 412                             ty::Uint(_) | ty::Int(_) => {}
 413                             _ => unreachable!("cast adt {} -> {}", from_ty, to_ty),
 414                         }
 415
 416                         let discr = crate::discriminant::codegen_get_discriminant(
 417                             fx,
 418                             operand,
 419                             fx.layout_of(to_ty),
 420                         );
 421                         lval.write_cvalue(fx, discr);
 422                     } else {
 423                         let to_clif_ty = fx.clif_type(to_ty).unwrap();
 424                         let from = operand.load_scalar(fx);
 425
 426                         let res = clif_int_or_float_cast(
 427                             fx,
 428                             from,
 429                             type_sign(from_ty),
 430                             to_clif_ty,
 431                             type_sign(to_ty),
 432                         );
 433                         lval.write_cvalue(fx, CValue::by_val(res, dest_layout));
 434                     }
 435                 }
 436                 Rvalue::Cast(CastKind::Pointer(PointerCast::ClosureFnPointer(_)), operand, _to_ty) => {
 437                     let operand = trans_operand(fx, operand);
 438                     match operand.layout().ty.kind {
 439                         ty::Closure(def_id, substs) => {
 440                             let instance = Instance::resolve_closure(
 441                                 fx.tcx,
 442                                 def_id,
 443                                 substs,
 444                                 ty::ClosureKind::FnOnce,
 445                             );
 446                             let func_ref = fx.get_function_ref(instance);
 447                             let func_addr = fx.bcx.ins().func_addr(fx.pointer_type, func_ref);
 448                             lval.write_cvalue(fx, CValue::by_val(func_addr, lval.layout()));
 449                         }
 450                         _ => bug!("{} cannot be cast to a fn ptr", operand.layout().ty),
 451                     }
 452                 }
 453                 Rvalue::Cast(CastKind::Pointer(PointerCast::Unsize), operand, _to_ty) => {
 454                     let operand = trans_operand(fx, operand);
 455                     operand.unsize_value(fx, lval);
 456                 }
 457                 Rvalue::Discriminant(place) => {
 458                     let place = trans_place(fx, place);
 459                     let value = place.to_cvalue(fx);
 460                     let discr =
 461                         crate::discriminant::codegen_get_discriminant(fx, value, dest_layout);
 462                     lval.write_cvalue(fx, discr);
 463                 }
 464                 Rvalue::Repeat(operand, times) => {
 465                     let operand = trans_operand(fx, operand);
 466                     for i in 0..*times {
 467                         let index = fx.bcx.ins().iconst(fx.pointer_type, i as i64);
 468                         let to = lval.place_index(fx, index);
 469                         to.write_cvalue(fx, operand);
 470                     }
 471                 }
 472                 Rvalue::Len(place) => {
 473                     let place = trans_place(fx, place);
 474                     let usize_layout = fx.layout_of(fx.tcx.types.usize);
 475                     let len = codegen_array_len(fx, place);
 476                     lval.write_cvalue(fx, CValue::by_val(len, usize_layout));
 477                 }
 478                 Rvalue::NullaryOp(NullOp::Box, content_ty) => {
 479                     use rustc::middle::lang_items::ExchangeMallocFnLangItem;
 480
 481                     let usize_type = fx.clif_type(fx.tcx.types.usize).unwrap();
 482                     let content_ty = fx.monomorphize(content_ty);
 483                     let layout = fx.layout_of(content_ty);
 484                     let llsize = fx.bcx.ins().iconst(usize_type, layout.size.bytes() as i64);
 485                     let llalign = fx
 486                         .bcx
 487                         .ins()
 488                         .iconst(usize_type, layout.align.abi.bytes() as i64);
 489                     let box_layout = fx.layout_of(fx.tcx.mk_box(content_ty));
 490
 491                     // Allocate space:
 492                     let def_id = match fx.tcx.lang_items().require(ExchangeMallocFnLangItem) {
 493                         Ok(id) => id,
 494                         Err(s) => {
 495                             fx.tcx
 496                                 .sess
 497                                 .fatal(&format!("allocation of `{}` {}", box_layout.ty, s));
 498                         }
 499                     };
 500                     let instance = ty::Instance::mono(fx.tcx, def_id);
 501                     let func_ref = fx.get_function_ref(instance);
 502                     let call = fx.bcx.ins().call(func_ref, &[llsize, llalign]);
 503                     let ptr = fx.bcx.inst_results(call)[0];
 504                     lval.write_cvalue(fx, CValue::by_val(ptr, box_layout));
 505                 }
 506                 Rvalue::NullaryOp(NullOp::SizeOf, ty) => {
 507                     assert!(lval
 508                         .layout()
 509                         .ty
 510                         .is_sized(fx.tcx.at(stmt.source_info.span), ParamEnv::reveal_all()));
 511                     let ty_size = fx.layout_of(fx.monomorphize(ty)).size.bytes();
 512                     let val = CValue::const_val(fx, fx.tcx.types.usize, ty_size.into());
 513                     lval.write_cvalue(fx, val);
 514                 }
 515                 Rvalue::Aggregate(kind, operands) => match **kind {
 516                     AggregateKind::Array(_ty) => {
 517                         for (i, operand) in operands.into_iter().enumerate() {
 518                             let operand = trans_operand(fx, operand);
 519                             let index = fx.bcx.ins().iconst(fx.pointer_type, i as i64);
 520                             let to = lval.place_index(fx, index);
 521                             to.write_cvalue(fx, operand);
 522                         }
 523                     }
 524                     _ => unreachable!("shouldn't exist at trans {:?}", to_place_and_rval.1),
 525                 },
 526             }
 527         }
 528         StatementKind::StorageLive(_)
 529         | StatementKind::StorageDead(_)
 530         | StatementKind::Nop
 531         | StatementKind::FakeRead(..)
 532         | StatementKind::Retag { .. }
 533         | StatementKind::AscribeUserType(..) => {}
 534
 535         StatementKind::InlineAsm(asm) => {
 536             use syntax::ast::Name;
 537             let InlineAsm {
 538                 asm,
 539                 outputs: _,
 540                 inputs: _,
 541             } = &**asm;
 542             let rustc_hir::InlineAsmInner {
 543                 asm: asm_code, // Name
 544                 outputs,       // Vec<Name>
 545                 inputs,        // Vec<Name>
 546                 clobbers,      // Vec<Name>
 547                 volatile,      // bool
 548                 alignstack,    // bool
 549                 dialect: _,    // syntax::ast::AsmDialect
 550                 asm_str_style: _,
 551             } = asm;
 552             match &*asm_code.as_str() {
 553                 "" => {
 554                     assert_eq!(inputs, &[Name::intern("r")]);
 555                     assert!(outputs.is_empty(), "{:?}", outputs);
 556
 557                     // Black box
 558                 }
 559                 "cpuid" | "cpuid\n" => {
 560                     assert_eq!(inputs, &[Name::intern("{eax}"), Name::intern("{ecx}")]);
 561
 562                     assert_eq!(outputs.len(), 4);
 563                     for (i, c) in (&["={eax}", "={ebx}", "={ecx}", "={edx}"])
 564                         .iter()
 565                         .enumerate()
 566                     {
 567                         assert_eq!(&outputs[i].constraint.as_str(), c);
 568                         assert!(!outputs[i].is_rw);
 569                         assert!(!outputs[i].is_indirect);
 570                     }
 571
 572                     assert_eq!(clobbers, &[Name::intern("rbx")]);
 573
 574                     assert!(!volatile);
 575                     assert!(!alignstack);
 576
 577                     crate::trap::trap_unimplemented(
 578                         fx,
 579                         "__cpuid_count arch intrinsic is not supported",
 580                     );
 581                 }
 582                 "xgetbv" => {
 583                     assert_eq!(inputs, &[Name::intern("{ecx}")]);
 584
 585                     assert_eq!(outputs.len(), 2);
 586                     for (i, c) in (&["={eax}", "={edx}"]).iter().enumerate() {
 587                         assert_eq!(&outputs[i].constraint.as_str(), c);
 588                         assert!(!outputs[i].is_rw);
 589                         assert!(!outputs[i].is_indirect);
 590                     }
 591
 592                     assert_eq!(clobbers, &[]);
 593
 594                     assert!(!volatile);
 595                     assert!(!alignstack);
 596
 597                     crate::trap::trap_unimplemented(fx, "_xgetbv arch intrinsic is not supported");
 598                 }
 599                 _ if fx.tcx.symbol_name(fx.instance).name.as_str() == "__rust_probestack" => {
 600                     crate::trap::trap_unimplemented(fx, "__rust_probestack is not supported");
 601                 }
 602                 _ => unimpl!("Inline assembly is not supported"),
 603             }
 604         }
 605     }
 606 }
 607
 608 fn codegen_array_len<'tcx>(
 609     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
 610     place: CPlace<'tcx>,
 611 ) -> Value {
 612     match place.layout().ty.kind {
 613         ty::Array(_elem_ty, len) => {
 614             let len = crate::constant::force_eval_const(fx, len)
 615                 .eval_usize(fx.tcx, ParamEnv::reveal_all()) as i64;
 616             fx.bcx.ins().iconst(fx.pointer_type, len)
 617         }
 618         ty::Slice(_elem_ty) => place
 619             .to_ptr_maybe_unsized(fx)
 620             .1
 621             .expect("Length metadata for slice place"),
 622         _ => bug!("Rvalue::Len({:?})", place),
 623     }
 624 }
 625
 626 pub fn trans_place<'tcx>(
 627     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
 628     place: &Place<'tcx>,
 629 ) -> CPlace<'tcx> {
 630     let mut cplace = match &place.base {
 631         PlaceBase::Local(local) => fx.get_local_place(*local),
 632         PlaceBase::Static(static_) => match static_.kind {
 633             StaticKind::Static => {
 634                 // Statics can't be generic, so `static_.ty` doesn't need to be monomorphized.
 635                 crate::constant::codegen_static_ref(fx, static_.def_id, static_.ty)
 636             }
 637             StaticKind::Promoted(promoted, substs) => {
 638                 let instance = Instance::new(static_.def_id, fx.monomorphize(&substs));
 639                 let ty = fx.monomorphize(&static_.ty);
 640                 crate::constant::trans_promoted(fx, instance, promoted, ty)
 641             }
 642         },
 643     };
 644
 645     for elem in &*place.projection {
 646         match *elem {
 647             PlaceElem::Deref => {
 648                 cplace = cplace.place_deref(fx);
 649             }
 650             PlaceElem::Field(field, _ty) => {
 651                 cplace = cplace.place_field(fx, field);
 652             }
 653             PlaceElem::Index(local) => {
 654                 let index = fx.get_local_place(local).to_cvalue(fx).load_scalar(fx);
 655                 cplace = cplace.place_index(fx, index);
 656             }
 657             PlaceElem::ConstantIndex {
 658                 offset,
 659                 min_length: _,
 660                 from_end,
 661             } => {
 662                 let index = if !from_end {
 663                     fx.bcx.ins().iconst(fx.pointer_type, offset as i64)
 664                 } else {
 665                     let len = codegen_array_len(fx, cplace);
 666                     fx.bcx.ins().iadd_imm(len, -(offset as i64))
 667                 };
 668                 cplace = cplace.place_index(fx, index);
 669             }
 670             PlaceElem::Subslice { from, to, from_end } => {
 671                 // These indices are generated by slice patterns.
 672                 // slice[from:-to] in Python terms.
 673
 674                 match cplace.layout().ty.kind {
 675                     ty::Array(elem_ty, len) => {
 676                         let elem_layout = fx.layout_of(elem_ty);
 677                         let ptr = cplace.to_ptr(fx);
 678                         let len = crate::constant::force_eval_const(fx, len)
 679                             .eval_usize(fx.tcx, ParamEnv::reveal_all());
 680                         cplace = CPlace::for_ptr(
 681                             ptr.offset_i64(fx, elem_layout.size.bytes() as i64 * from as i64),
 682                             fx.layout_of(fx.tcx.mk_array(elem_ty, len - from as u64 - to as u64)),
 683                         );
 684                     }
 685                     ty::Slice(elem_ty) => {
 686                         assert!(from_end, "slice subslices should be `from_end`");
 687                         let elem_layout = fx.layout_of(elem_ty);
 688                         let (ptr, len) = cplace.to_ptr_maybe_unsized(fx);
 689                         let len = len.unwrap();
 690                         cplace = CPlace::for_ptr_with_extra(
 691                             ptr.offset_i64(fx, elem_layout.size.bytes() as i64 * from as i64),
 692                             fx.bcx.ins().iadd_imm(len, -(from as i64 + to as i64)),
 693                             cplace.layout(),
 694                         );
 695                     }
 696                     _ => unreachable!(),
 697                 }
 698             }
 699             PlaceElem::Downcast(_adt_def, variant) => {
 700                 cplace = cplace.downcast_variant(fx, variant);
 701             }
 702         }
 703     }
 704
 705     cplace
 706 }
 707
 708 pub fn trans_operand<'tcx>(
 709     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
 710     operand: &Operand<'tcx>,
 711 ) -> CValue<'tcx> {
 712     match operand {
 713         Operand::Move(place) | Operand::Copy(place) => {
 714             let cplace = trans_place(fx, place);
 715             cplace.to_cvalue(fx)
 716         }
 717         Operand::Constant(const_) => crate::constant::trans_constant(fx, const_),
 718     }
 719 }