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 block's
  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: HashMap::new(),
  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     if fx.mir.args_iter().any(|arg| fx.layout_of(fx.monomorphize(&fx.mir.local_decls[arg].ty)).abi.is_uninhabited()) {
  61         let entry_block = fx.bcx.create_block();
  62         fx.bcx.append_block_params_for_function_params(entry_block);
  63         fx.bcx.switch_to_block(entry_block);
  64         crate::trap::trap_unreachable(&mut fx, "function has uninhabited argument");
  65     } else {
  66         tcx.sess.time("codegen clif ir", || {
  67             tcx.sess.time("codegen prelude", || crate::abi::codegen_fn_prelude(&mut fx, start_block));
  68             codegen_fn_content(&mut fx);
  69         });
  70     }
  71
  72     // Recover all necessary data from fx, before accessing func will prevent future access to it.
  73     let instance = fx.instance;
  74     let mut clif_comments = fx.clif_comments;
  75     let source_info_set = fx.source_info_set;
  76     let local_map = fx.local_map;
  77     let cold_blocks = fx.cold_blocks;
  78
  79     #[cfg(debug_assertions)]
  80     crate::pretty_clif::write_clif_file(cx.tcx, "unopt", instance, &context.func, &clif_comments, None);
  81
  82     // Verify function
  83     verify_func(tcx, &clif_comments, &context.func);
  84
  85     // Perform rust specific optimizations
  86     tcx.sess.time("optimize clif ir", || {
  87         crate::optimize::optimize_function(tcx, instance, context, &cold_blocks, &mut clif_comments);
  88     });
  89
  90     // Define function
  91     let module = &mut cx.module;
  92     tcx.sess.time("define function", || module.define_function(func_id, context).unwrap());
  93
  94     // Write optimized function to file for debugging
  95     #[cfg(debug_assertions)]
  96     {
  97         let value_ranges = context
  98             .build_value_labels_ranges(cx.module.isa())
  99             .expect("value location ranges");
 100
 101         crate::pretty_clif::write_clif_file(
 102             cx.tcx,
 103             "opt",
 104             instance,
 105             &context.func,
 106             &clif_comments,
 107             Some(&value_ranges),
 108         );
 109     }
 110
 111     // Define debuginfo for function
 112     let isa = cx.module.isa();
 113     tcx.sess.time("generate debug info", || {
 114         debug_context
 115             .as_mut()
 116             .map(|x| x.define(context, isa, &source_info_set, local_map));
 117     });
 118
 119     // Clear context to make it usable for the next function
 120     context.clear();
 121 }
 122
 123 pub fn verify_func(tcx: TyCtxt, writer: &crate::pretty_clif::CommentWriter, func: &Function) {
 124     tcx.sess.time("verify clif ir", || {
 125         let flags = settings::Flags::new(settings::builder());
 126         match ::cranelift_codegen::verify_function(&func, &flags) {
 127             Ok(_) => {}
 128             Err(err) => {
 129                 tcx.sess.err(&format!("{:?}", err));
 130                 let pretty_error = ::cranelift_codegen::print_errors::pretty_verifier_error(
 131                     &func,
 132                     None,
 133                     Some(Box::new(writer)),
 134                     err,
 135                 );
 136                 tcx.sess
 137                     .fatal(&format!("cranelift verify error:\n{}", pretty_error));
 138             }
 139         }
 140     });
 141 }
 142
 143 fn codegen_fn_content(fx: &mut FunctionCx<'_, '_, impl Backend>) {
 144     for (bb, bb_data) in fx.mir.basic_blocks().iter_enumerated() {
 145         let block = fx.get_block(bb);
 146         fx.bcx.switch_to_block(block);
 147
 148         if bb_data.is_cleanup {
 149             // Unwinding after panicking is not supported
 150             continue;
 151
 152             // FIXME once unwinding is supported uncomment next lines
 153             // // Unwinding is unlikely to happen, so mark cleanup block's as cold.
 154             // fx.cold_blocks.insert(block);
 155         }
 156
 157         fx.bcx.ins().nop();
 158         for stmt in &bb_data.statements {
 159             fx.set_debug_loc(stmt.source_info);
 160             trans_stmt(fx, block, stmt);
 161         }
 162
 163         #[cfg(debug_assertions)]
 164         {
 165             let mut terminator_head = "\n".to_string();
 166             bb_data
 167                 .terminator()
 168                 .kind
 169                 .fmt_head(&mut terminator_head)
 170                 .unwrap();
 171             let inst = fx.bcx.func.layout.last_inst(block).unwrap();
 172             fx.add_comment(inst, terminator_head);
 173         }
 174
 175         fx.set_debug_loc(bb_data.terminator().source_info);
 176
 177         match &bb_data.terminator().kind {
 178             TerminatorKind::Goto { target } => {
 179                 let block = fx.get_block(*target);
 180                 fx.bcx.ins().jump(block, &[]);
 181             }
 182             TerminatorKind::Return => {
 183                 crate::abi::codegen_return(fx);
 184             }
 185             TerminatorKind::Assert {
 186                 cond,
 187                 expected,
 188                 msg,
 189                 target,
 190                 cleanup: _,
 191             } => {
 192                 if !fx.tcx.sess.overflow_checks() {
 193                     if let mir::AssertKind::OverflowNeg = *msg {
 194                         let target = fx.get_block(*target);
 195                         fx.bcx.ins().jump(target, &[]);
 196                         continue;
 197                     }
 198                 }
 199                 let cond = trans_operand(fx, cond).load_scalar(fx);
 200
 201                 let target = fx.get_block(*target);
 202                 let failure = fx.bcx.create_block();
 203                 fx.cold_blocks.insert(failure);
 204
 205                 if *expected {
 206                     fx.bcx.ins().brz(cond, failure, &[]);
 207                 } else {
 208                     fx.bcx.ins().brnz(cond, failure, &[]);
 209                 };
 210                 fx.bcx.ins().jump(target, &[]);
 211
 212                 fx.bcx.switch_to_block(failure);
 213                 trap_panic(
 214                     fx,
 215                     format!(
 216                         "[panic] Assert {:?} at {:?} failed.",
 217                         msg,
 218                         bb_data.terminator().source_info.span
 219                     ),
 220                 );
 221             }
 222
 223             TerminatorKind::SwitchInt {
 224                 discr,
 225                 switch_ty: _,
 226                 values,
 227                 targets,
 228             } => {
 229                 let discr = trans_operand(fx, discr).load_scalar(fx);
 230                 let mut switch = ::cranelift_frontend::Switch::new();
 231                 for (i, value) in values.iter().enumerate() {
 232                     let block = fx.get_block(targets[i]);
 233                     switch.set_entry(*value as u64, block);
 234                 }
 235                 let otherwise_block = fx.get_block(targets[targets.len() - 1]);
 236                 switch.emit(&mut fx.bcx, discr, otherwise_block);
 237             }
 238             TerminatorKind::Call {
 239                 func,
 240                 args,
 241                 destination,
 242                 cleanup: _,
 243                 from_hir_call: _,
 244             } => {
 245                 fx.tcx.sess.time("codegen call", || crate::abi::codegen_terminator_call(
 246                     fx,
 247                     bb_data.terminator().source_info.span,
 248                     func,
 249                     args,
 250                     destination,
 251                 ));
 252             }
 253             TerminatorKind::Resume | TerminatorKind::Abort => {
 254                 trap_unreachable(fx, "[corruption] Unwinding bb reached.");
 255             }
 256             TerminatorKind::Unreachable => {
 257                 trap_unreachable(fx, "[corruption] Hit unreachable code.");
 258             }
 259             TerminatorKind::Yield { .. }
 260             | TerminatorKind::FalseEdges { .. }
 261             | TerminatorKind::FalseUnwind { .. }
 262             | TerminatorKind::DropAndReplace { .. }
 263             | TerminatorKind::GeneratorDrop => {
 264                 bug!("shouldn't exist at trans {:?}", bb_data.terminator());
 265             }
 266             TerminatorKind::Drop {
 267                 location,
 268                 target,
 269                 unwind: _,
 270             } => {
 271                 let drop_place = trans_place(fx, location);
 272                 crate::abi::codegen_drop(fx, bb_data.terminator().source_info.span, drop_place);
 273
 274                 let target_block = fx.get_block(*target);
 275                 fx.bcx.ins().jump(target_block, &[]);
 276             }
 277         };
 278     }
 279
 280     fx.bcx.seal_all_blocks();
 281     fx.bcx.finalize();
 282 }
 283
 284 fn trans_stmt<'tcx>(
 285     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
 286     #[allow(unused_variables)]
 287     cur_block: Block,
 288     stmt: &Statement<'tcx>,
 289 ) {
 290     let _print_guard = PrintOnPanic(|| format!("stmt {:?}", stmt));
 291
 292     fx.set_debug_loc(stmt.source_info);
 293
 294     #[cfg(false_debug_assertions)]
 295     match &stmt.kind {
 296         StatementKind::StorageLive(..) | StatementKind::StorageDead(..) => {} // Those are not very useful
 297         _ => {
 298             let inst = fx.bcx.func.layout.last_inst(cur_block).unwrap();
 299             fx.add_comment(inst, format!("{:?}", stmt));
 300         }
 301     }
 302
 303     match &stmt.kind {
 304         StatementKind::SetDiscriminant {
 305             place,
 306             variant_index,
 307         } => {
 308             let place = trans_place(fx, place);
 309             crate::discriminant::codegen_set_discriminant(fx, place, *variant_index);
 310         }
 311         StatementKind::Assign(to_place_and_rval) => {
 312             let lval = trans_place(fx, &to_place_and_rval.0);
 313             let dest_layout = lval.layout();
 314             match &to_place_and_rval.1 {
 315                 Rvalue::Use(operand) => {
 316                     let val = trans_operand(fx, operand);
 317                     lval.write_cvalue(fx, val);
 318                 }
 319                 Rvalue::Ref(_, _, place) | Rvalue::AddressOf(_, place) => {
 320                     let place = trans_place(fx, place);
 321                     place.write_place_ref(fx, lval);
 322                 }
 323                 Rvalue::BinaryOp(bin_op, lhs, rhs) => {
 324                     let lhs = trans_operand(fx, lhs);
 325                     let rhs = trans_operand(fx, rhs);
 326
 327                     let res = crate::num::codegen_binop(fx, *bin_op, lhs, rhs);
 328                     lval.write_cvalue(fx, res);
 329                 }
 330                 Rvalue::CheckedBinaryOp(bin_op, lhs, rhs) => {
 331                     let lhs = trans_operand(fx, lhs);
 332                     let rhs = trans_operand(fx, rhs);
 333
 334                     let res = if !fx.tcx.sess.overflow_checks() {
 335                         let val =
 336                             crate::num::trans_int_binop(fx, *bin_op, lhs, rhs).load_scalar(fx);
 337                         let is_overflow = fx.bcx.ins().iconst(types::I8, 0);
 338                         CValue::by_val_pair(val, is_overflow, lval.layout())
 339                     } else {
 340                         crate::num::trans_checked_int_binop(fx, *bin_op, lhs, rhs)
 341                     };
 342
 343                     lval.write_cvalue(fx, res);
 344                 }
 345                 Rvalue::UnaryOp(un_op, operand) => {
 346                     let operand = trans_operand(fx, operand);
 347                     let layout = operand.layout();
 348                     let val = operand.load_scalar(fx);
 349                     let res = match un_op {
 350                         UnOp::Not => {
 351                             match layout.ty.kind {
 352                                 ty::Bool => {
 353                                     let val = fx.bcx.ins().uextend(types::I32, val); // WORKAROUND for CraneStation/cranelift#466
 354                                     let res = fx.bcx.ins().icmp_imm(IntCC::Equal, val, 0);
 355                                     CValue::by_val(fx.bcx.ins().bint(types::I8, res), layout)
 356                                 }
 357                                 ty::Uint(_) | ty::Int(_) => {
 358                                     CValue::by_val(fx.bcx.ins().bnot(val), layout)
 359                                 }
 360                                 _ => unreachable!("un op Not for {:?}", layout.ty),
 361                             }
 362                         }
 363                         UnOp::Neg => match layout.ty.kind {
 364                             ty::Int(IntTy::I128) => {
 365                                 // FIXME remove this case once ineg.i128 works
 366                                 let zero = CValue::const_val(fx, layout, 0);
 367                                 crate::num::trans_int_binop(fx, BinOp::Sub, zero, operand)
 368                             }
 369                             ty::Int(_) => {
 370                                 CValue::by_val(fx.bcx.ins().ineg(val), layout)
 371                             }
 372                             ty::Float(_) => {
 373                                 CValue::by_val(fx.bcx.ins().fneg(val), layout)
 374                             }
 375                             _ => unreachable!("un op Neg for {:?}", layout.ty),
 376                         },
 377                     };
 378                     lval.write_cvalue(fx, res);
 379                 }
 380                 Rvalue::Cast(CastKind::Pointer(PointerCast::ReifyFnPointer), operand, to_ty) => {
 381                     let from_ty = fx.monomorphize(&operand.ty(&fx.mir.local_decls, fx.tcx));
 382                     let to_layout = fx.layout_of(fx.monomorphize(to_ty));
 383                     match from_ty.kind {
 384                         ty::FnDef(def_id, substs) => {
 385                             let func_ref = fx.get_function_ref(
 386                                 Instance::resolve_for_fn_ptr(fx.tcx, ParamEnv::reveal_all(), def_id, substs)
 387                                     .unwrap(),
 388                             );
 389                             let func_addr = fx.bcx.ins().func_addr(fx.pointer_type, func_ref);
 390                             lval.write_cvalue(fx, CValue::by_val(func_addr, to_layout));
 391                         }
 392                         _ => bug!("Trying to ReifyFnPointer on non FnDef {:?}", from_ty),
 393                     }
 394                 }
 395                 Rvalue::Cast(CastKind::Pointer(PointerCast::UnsafeFnPointer), operand, to_ty)
 396                 | Rvalue::Cast(CastKind::Pointer(PointerCast::MutToConstPointer), operand, to_ty)
 397                 | Rvalue::Cast(CastKind::Pointer(PointerCast::ArrayToPointer), operand, to_ty) => {
 398                     let to_layout = fx.layout_of(fx.monomorphize(to_ty));
 399                     let operand = trans_operand(fx, operand);
 400                     lval.write_cvalue(fx, operand.unchecked_cast_to(to_layout));
 401                 }
 402                 Rvalue::Cast(CastKind::Misc, operand, to_ty) => {
 403                     let operand = trans_operand(fx, operand);
 404                     let from_ty = operand.layout().ty;
 405                     let to_ty = fx.monomorphize(to_ty);
 406
 407                     fn is_fat_ptr<'tcx>(
 408                         fx: &FunctionCx<'_, 'tcx, impl Backend>,
 409                         ty: Ty<'tcx>,
 410                     ) -> bool {
 411                         ty.builtin_deref(true)
 412                             .map(
 413                                 |ty::TypeAndMut {
 414                                      ty: pointee_ty,
 415                                      mutbl: _,
 416                                  }| has_ptr_meta(fx.tcx, pointee_ty),
 417                             )
 418                             .unwrap_or(false)
 419                     }
 420
 421                     if is_fat_ptr(fx, from_ty) {
 422                         if is_fat_ptr(fx, to_ty) {
 423                             // fat-ptr -> fat-ptr
 424                             lval.write_cvalue(fx, operand.unchecked_cast_to(dest_layout));
 425                         } else {
 426                             // fat-ptr -> thin-ptr
 427                             let (ptr, _extra) = operand.load_scalar_pair(fx);
 428                             lval.write_cvalue(fx, CValue::by_val(ptr, dest_layout))
 429                         }
 430                     } else if let ty::Adt(adt_def, _substs) = from_ty.kind {
 431                         // enum -> discriminant value
 432                         assert!(adt_def.is_enum());
 433                         match to_ty.kind {
 434                             ty::Uint(_) | ty::Int(_) => {}
 435                             _ => unreachable!("cast adt {} -> {}", from_ty, to_ty),
 436                         }
 437
 438                         let discr = crate::discriminant::codegen_get_discriminant(
 439                             fx,
 440                             operand,
 441                             fx.layout_of(to_ty),
 442                         );
 443                         lval.write_cvalue(fx, discr);
 444                     } else {
 445                         let to_clif_ty = fx.clif_type(to_ty).unwrap();
 446                         let from = operand.load_scalar(fx);
 447
 448                         let res = clif_int_or_float_cast(
 449                             fx,
 450                             from,
 451                             type_sign(from_ty),
 452                             to_clif_ty,
 453                             type_sign(to_ty),
 454                         );
 455                         lval.write_cvalue(fx, CValue::by_val(res, dest_layout));
 456                     }
 457                 }
 458                 Rvalue::Cast(CastKind::Pointer(PointerCast::ClosureFnPointer(_)), operand, _to_ty) => {
 459                     let operand = trans_operand(fx, operand);
 460                     match operand.layout().ty.kind {
 461                         ty::Closure(def_id, substs) => {
 462                             let instance = Instance::resolve_closure(
 463                                 fx.tcx,
 464                                 def_id,
 465                                 substs,
 466                                 ty::ClosureKind::FnOnce,
 467                             );
 468                             let func_ref = fx.get_function_ref(instance);
 469                             let func_addr = fx.bcx.ins().func_addr(fx.pointer_type, func_ref);
 470                             lval.write_cvalue(fx, CValue::by_val(func_addr, lval.layout()));
 471                         }
 472                         _ => bug!("{} cannot be cast to a fn ptr", operand.layout().ty),
 473                     }
 474                 }
 475                 Rvalue::Cast(CastKind::Pointer(PointerCast::Unsize), operand, _to_ty) => {
 476                     let operand = trans_operand(fx, operand);
 477                     operand.unsize_value(fx, lval);
 478                 }
 479                 Rvalue::Discriminant(place) => {
 480                     let place = trans_place(fx, place);
 481                     let value = place.to_cvalue(fx);
 482                     let discr =
 483                         crate::discriminant::codegen_get_discriminant(fx, value, dest_layout);
 484                     lval.write_cvalue(fx, discr);
 485                 }
 486                 Rvalue::Repeat(operand, times) => {
 487                     let operand = trans_operand(fx, operand);
 488                     for i in 0..*times {
 489                         let index = fx.bcx.ins().iconst(fx.pointer_type, i as i64);
 490                         let to = lval.place_index(fx, index);
 491                         to.write_cvalue(fx, operand);
 492                     }
 493                 }
 494                 Rvalue::Len(place) => {
 495                     let place = trans_place(fx, place);
 496                     let usize_layout = fx.layout_of(fx.tcx.types.usize);
 497                     let len = codegen_array_len(fx, place);
 498                     lval.write_cvalue(fx, CValue::by_val(len, usize_layout));
 499                 }
 500                 Rvalue::NullaryOp(NullOp::Box, content_ty) => {
 501                     use rustc::middle::lang_items::ExchangeMallocFnLangItem;
 502
 503                     let usize_type = fx.clif_type(fx.tcx.types.usize).unwrap();
 504                     let content_ty = fx.monomorphize(content_ty);
 505                     let layout = fx.layout_of(content_ty);
 506                     let llsize = fx.bcx.ins().iconst(usize_type, layout.size.bytes() as i64);
 507                     let llalign = fx
 508                         .bcx
 509                         .ins()
 510                         .iconst(usize_type, layout.align.abi.bytes() as i64);
 511                     let box_layout = fx.layout_of(fx.tcx.mk_box(content_ty));
 512
 513                     // Allocate space:
 514                     let def_id = match fx.tcx.lang_items().require(ExchangeMallocFnLangItem) {
 515                         Ok(id) => id,
 516                         Err(s) => {
 517                             fx.tcx
 518                                 .sess
 519                                 .fatal(&format!("allocation of `{}` {}", box_layout.ty, s));
 520                         }
 521                     };
 522                     let instance = ty::Instance::mono(fx.tcx, def_id);
 523                     let func_ref = fx.get_function_ref(instance);
 524                     let call = fx.bcx.ins().call(func_ref, &[llsize, llalign]);
 525                     let ptr = fx.bcx.inst_results(call)[0];
 526                     lval.write_cvalue(fx, CValue::by_val(ptr, box_layout));
 527                 }
 528                 Rvalue::NullaryOp(NullOp::SizeOf, ty) => {
 529                     assert!(lval
 530                         .layout()
 531                         .ty
 532                         .is_sized(fx.tcx.at(stmt.source_info.span), ParamEnv::reveal_all()));
 533                     let ty_size = fx.layout_of(fx.monomorphize(ty)).size.bytes();
 534                     let val = CValue::const_val(fx, fx.layout_of(fx.tcx.types.usize), ty_size.into());
 535                     lval.write_cvalue(fx, val);
 536                 }
 537                 Rvalue::Aggregate(kind, operands) => match **kind {
 538                     AggregateKind::Array(_ty) => {
 539                         for (i, operand) in operands.into_iter().enumerate() {
 540                             let operand = trans_operand(fx, operand);
 541                             let index = fx.bcx.ins().iconst(fx.pointer_type, i as i64);
 542                             let to = lval.place_index(fx, index);
 543                             to.write_cvalue(fx, operand);
 544                         }
 545                     }
 546                     _ => unreachable!("shouldn't exist at trans {:?}", to_place_and_rval.1),
 547                 },
 548             }
 549         }
 550         StatementKind::StorageLive(_)
 551         | StatementKind::StorageDead(_)
 552         | StatementKind::Nop
 553         | StatementKind::FakeRead(..)
 554         | StatementKind::Retag { .. }
 555         | StatementKind::AscribeUserType(..) => {}
 556
 557         StatementKind::InlineAsm(asm) => {
 558             use syntax::ast::Name;
 559             let InlineAsm {
 560                 asm,
 561                 outputs: _,
 562                 inputs: _,
 563             } = &**asm;
 564             let rustc_hir::InlineAsmInner {
 565                 asm: asm_code, // Name
 566                 outputs,       // Vec<Name>
 567                 inputs,        // Vec<Name>
 568                 clobbers,      // Vec<Name>
 569                 volatile,      // bool
 570                 alignstack,    // bool
 571                 dialect: _,    // syntax::ast::AsmDialect
 572                 asm_str_style: _,
 573             } = asm;
 574             match &*asm_code.as_str() {
 575                 "" => {
 576                     assert_eq!(inputs, &[Name::intern("r")]);
 577                     assert!(outputs.is_empty(), "{:?}", outputs);
 578
 579                     // Black box
 580                 }
 581                 "cpuid" | "cpuid\n" => {
 582                     assert_eq!(inputs, &[Name::intern("{eax}"), Name::intern("{ecx}")]);
 583
 584                     assert_eq!(outputs.len(), 4);
 585                     for (i, c) in (&["={eax}", "={ebx}", "={ecx}", "={edx}"])
 586                         .iter()
 587                         .enumerate()
 588                     {
 589                         assert_eq!(&outputs[i].constraint.as_str(), c);
 590                         assert!(!outputs[i].is_rw);
 591                         assert!(!outputs[i].is_indirect);
 592                     }
 593
 594                     assert_eq!(clobbers, &[Name::intern("rbx")]);
 595
 596                     assert!(!volatile);
 597                     assert!(!alignstack);
 598
 599                     crate::trap::trap_unimplemented(
 600                         fx,
 601                         "__cpuid_count arch intrinsic is not supported",
 602                     );
 603                 }
 604                 "xgetbv" => {
 605                     assert_eq!(inputs, &[Name::intern("{ecx}")]);
 606
 607                     assert_eq!(outputs.len(), 2);
 608                     for (i, c) in (&["={eax}", "={edx}"]).iter().enumerate() {
 609                         assert_eq!(&outputs[i].constraint.as_str(), c);
 610                         assert!(!outputs[i].is_rw);
 611                         assert!(!outputs[i].is_indirect);
 612                     }
 613
 614                     assert_eq!(clobbers, &[]);
 615
 616                     assert!(!volatile);
 617                     assert!(!alignstack);
 618
 619                     crate::trap::trap_unimplemented(fx, "_xgetbv arch intrinsic is not supported");
 620                 }
 621                 _ if fx.tcx.symbol_name(fx.instance).name.as_str() == "__rust_probestack" => {
 622                     crate::trap::trap_unimplemented(fx, "__rust_probestack is not supported");
 623                 }
 624                 _ => unimpl!("Inline assembly is not supported"),
 625             }
 626         }
 627     }
 628 }
 629
 630 fn codegen_array_len<'tcx>(
 631     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
 632     place: CPlace<'tcx>,
 633 ) -> Value {
 634     match place.layout().ty.kind {
 635         ty::Array(_elem_ty, len) => {
 636             let len = fx.monomorphize(&len)
 637                 .eval(fx.tcx, ParamEnv::reveal_all())
 638                 .eval_usize(fx.tcx, ParamEnv::reveal_all()) as i64;
 639             fx.bcx.ins().iconst(fx.pointer_type, len)
 640         }
 641         ty::Slice(_elem_ty) => place
 642             .to_ptr_maybe_unsized(fx)
 643             .1
 644             .expect("Length metadata for slice place"),
 645         _ => bug!("Rvalue::Len({:?})", place),
 646     }
 647 }
 648
 649 pub fn trans_place<'tcx>(
 650     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
 651     place: &Place<'tcx>,
 652 ) -> CPlace<'tcx> {
 653     let mut cplace = fx.get_local_place(place.local);
 654
 655     for elem in &*place.projection {
 656         match *elem {
 657             PlaceElem::Deref => {
 658                 cplace = cplace.place_deref(fx);
 659             }
 660             PlaceElem::Field(field, _ty) => {
 661                 cplace = cplace.place_field(fx, field);
 662             }
 663             PlaceElem::Index(local) => {
 664                 let index = fx.get_local_place(local).to_cvalue(fx).load_scalar(fx);
 665                 cplace = cplace.place_index(fx, index);
 666             }
 667             PlaceElem::ConstantIndex {
 668                 offset,
 669                 min_length: _,
 670                 from_end,
 671             } => {
 672                 let index = if !from_end {
 673                     fx.bcx.ins().iconst(fx.pointer_type, offset as i64)
 674                 } else {
 675                     let len = codegen_array_len(fx, cplace);
 676                     fx.bcx.ins().iadd_imm(len, -(offset as i64))
 677                 };
 678                 cplace = cplace.place_index(fx, index);
 679             }
 680             PlaceElem::Subslice { from, to, from_end } => {
 681                 // These indices are generated by slice patterns.
 682                 // slice[from:-to] in Python terms.
 683
 684                 match cplace.layout().ty.kind {
 685                     ty::Array(elem_ty, _len) => {
 686                         assert!(!from_end, "array subslices are never `from_end`");
 687                         let elem_layout = fx.layout_of(elem_ty);
 688                         let ptr = cplace.to_ptr(fx);
 689                         cplace = CPlace::for_ptr(
 690                             ptr.offset_i64(fx, elem_layout.size.bytes() as i64 * from as i64),
 691                             fx.layout_of(fx.tcx.mk_array(elem_ty, to as u64 - from as u64)),
 692                         );
 693                     }
 694                     ty::Slice(elem_ty) => {
 695                         assert!(from_end, "slice subslices should be `from_end`");
 696                         let elem_layout = fx.layout_of(elem_ty);
 697                         let (ptr, len) = cplace.to_ptr_maybe_unsized(fx);
 698                         let len = len.unwrap();
 699                         cplace = CPlace::for_ptr_with_extra(
 700                             ptr.offset_i64(fx, elem_layout.size.bytes() as i64 * from as i64),
 701                             fx.bcx.ins().iadd_imm(len, -(from as i64 + to as i64)),
 702                             cplace.layout(),
 703                         );
 704                     }
 705                     _ => unreachable!(),
 706                 }
 707             }
 708             PlaceElem::Downcast(_adt_def, variant) => {
 709                 cplace = cplace.downcast_variant(fx, variant);
 710             }
 711         }
 712     }
 713
 714     cplace
 715 }
 716
 717 pub fn trans_operand<'tcx>(
 718     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
 719     operand: &Operand<'tcx>,
 720 ) -> CValue<'tcx> {
 721     match operand {
 722         Operand::Move(place) | Operand::Copy(place) => {
 723             let cplace = trans_place(fx, place);
 724             cplace.to_cvalue(fx)
 725         }
 726         Operand::Constant(const_) => crate::constant::trans_constant(fx, const_),
 727     }
 728 }