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