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                 if *expected {
 186                     fx.bcx.ins().brnz(cond, target, &[]);
 187                 } else {
 188                     fx.bcx.ins().brz(cond, target, &[]);
 189                 };
 190                 trap_panic(
 191                     fx,
 192                     format!(
 193                         "[panic] Assert {:?} at {:?} failed.",
 194                         msg,
 195                         bb_data.terminator().source_info.span
 196                     ),
 197                 );
 198             }
 199
 200             TerminatorKind::SwitchInt {
 201                 discr,
 202                 switch_ty: _,
 203                 values,
 204                 targets,
 205             } => {
 206                 let discr = trans_operand(fx, discr).load_scalar(fx);
 207                 let mut switch = ::cranelift_frontend::Switch::new();
 208                 for (i, value) in values.iter().enumerate() {
 209                     let ebb = fx.get_ebb(targets[i]);
 210                     switch.set_entry(*value as u64, ebb);
 211                 }
 212                 let otherwise_ebb = fx.get_ebb(targets[targets.len() - 1]);
 213                 switch.emit(&mut fx.bcx, discr, otherwise_ebb);
 214             }
 215             TerminatorKind::Call {
 216                 func,
 217                 args,
 218                 destination,
 219                 cleanup: _,
 220                 from_hir_call: _,
 221             } => {
 222                 crate::abi::codegen_terminator_call(
 223                     fx,
 224                     func,
 225                     args,
 226                     destination,
 227                     bb_data.terminator().source_info.span,
 228                 );
 229             }
 230             TerminatorKind::Resume | TerminatorKind::Abort => {
 231                 trap_unreachable(fx, "[corruption] Unwinding bb reached.");
 232             }
 233             TerminatorKind::Unreachable => {
 234                 trap_unreachable(fx, "[corruption] Hit unreachable code.");
 235             }
 236             TerminatorKind::Yield { .. }
 237             | TerminatorKind::FalseEdges { .. }
 238             | TerminatorKind::FalseUnwind { .. }
 239             | TerminatorKind::DropAndReplace { .. }
 240             | TerminatorKind::GeneratorDrop => {
 241                 bug!("shouldn't exist at trans {:?}", bb_data.terminator());
 242             }
 243             TerminatorKind::Drop {
 244                 location,
 245                 target,
 246                 unwind: _,
 247             } => {
 248                 let drop_place = trans_place(fx, location);
 249                 crate::abi::codegen_drop(fx, drop_place);
 250
 251                 let target_ebb = fx.get_ebb(*target);
 252                 fx.bcx.ins().jump(target_ebb, &[]);
 253             }
 254         };
 255     }
 256
 257     fx.bcx.seal_all_blocks();
 258     fx.bcx.finalize();
 259 }
 260
 261 fn trans_stmt<'tcx>(
 262     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
 263     cur_ebb: Ebb,
 264     stmt: &Statement<'tcx>,
 265 ) {
 266     let _print_guard = PrintOnPanic(|| format!("stmt {:?}", stmt));
 267
 268     fx.set_debug_loc(stmt.source_info);
 269
 270     #[cfg(debug_assertions)]
 271     match &stmt.kind {
 272         StatementKind::StorageLive(..) | StatementKind::StorageDead(..) => {} // Those are not very useful
 273         _ => {
 274             let inst = fx.bcx.func.layout.last_inst(cur_ebb).unwrap();
 275             fx.add_comment(inst, format!("{:?}", stmt));
 276         }
 277     }
 278
 279     match &stmt.kind {
 280         StatementKind::SetDiscriminant {
 281             place,
 282             variant_index,
 283         } => {
 284             let place = trans_place(fx, place);
 285             crate::discriminant::codegen_set_discriminant(fx, place, *variant_index);
 286         }
 287         StatementKind::Assign(to_place_and_rval) => {
 288             let lval = trans_place(fx, &to_place_and_rval.0);
 289             let dest_layout = lval.layout();
 290             match &to_place_and_rval.1 {
 291                 Rvalue::Use(operand) => {
 292                     let val = trans_operand(fx, operand);
 293                     lval.write_cvalue(fx, val);
 294                 }
 295                 Rvalue::Ref(_, _, place) | Rvalue::AddressOf(_, place) => {
 296                     let place = trans_place(fx, place);
 297                     place.write_place_ref(fx, lval);
 298                 }
 299                 Rvalue::BinaryOp(bin_op, lhs, rhs) => {
 300                     let lhs = trans_operand(fx, lhs);
 301                     let rhs = trans_operand(fx, rhs);
 302
 303                     let res = crate::num::codegen_binop(fx, *bin_op, lhs, rhs);
 304                     lval.write_cvalue(fx, res);
 305                 }
 306                 Rvalue::CheckedBinaryOp(bin_op, lhs, rhs) => {
 307                     let lhs = trans_operand(fx, lhs);
 308                     let rhs = trans_operand(fx, rhs);
 309
 310                     let res = if !fx.tcx.sess.overflow_checks() {
 311                         let val =
 312                             crate::num::trans_int_binop(fx, *bin_op, lhs, rhs).load_scalar(fx);
 313                         let is_overflow = fx.bcx.ins().iconst(types::I8, 0);
 314                         CValue::by_val_pair(val, is_overflow, lval.layout())
 315                     } else {
 316                         crate::num::trans_checked_int_binop(fx, *bin_op, lhs, rhs)
 317                     };
 318
 319                     lval.write_cvalue(fx, res);
 320                 }
 321                 Rvalue::UnaryOp(un_op, operand) => {
 322                     let operand = trans_operand(fx, operand);
 323                     let layout = operand.layout();
 324                     let val = operand.load_scalar(fx);
 325                     let res = match un_op {
 326                         UnOp::Not => {
 327                             match layout.ty.kind {
 328                                 ty::Bool => {
 329                                     let val = fx.bcx.ins().uextend(types::I32, val); // WORKAROUND for CraneStation/cranelift#466
 330                                     let res = fx.bcx.ins().icmp_imm(IntCC::Equal, val, 0);
 331                                     CValue::by_val(fx.bcx.ins().bint(types::I8, res), layout)
 332                                 }
 333                                 ty::Uint(_) | ty::Int(_) => {
 334                                     CValue::by_val(fx.bcx.ins().bnot(val), layout)
 335                                 }
 336                                 _ => unimplemented!("un op Not for {:?}", layout.ty),
 337                             }
 338                         }
 339                         UnOp::Neg => match layout.ty.kind {
 340                             ty::Int(_) => {
 341                                 let zero = CValue::const_val(fx, layout.ty, 0);
 342                                 crate::num::trans_int_binop(fx, BinOp::Sub, zero, operand)
 343                             }
 344                             ty::Float(_) => {
 345                                 CValue::by_val(fx.bcx.ins().fneg(val), layout)
 346                             }
 347                             _ => unimplemented!("un op Neg for {:?}", layout.ty),
 348                         },
 349                     };
 350                     lval.write_cvalue(fx, res);
 351                 }
 352                 Rvalue::Cast(CastKind::Pointer(PointerCast::ReifyFnPointer), operand, to_ty) => {
 353                     let from_ty = fx.monomorphize(&operand.ty(&fx.mir.local_decls, fx.tcx));
 354                     let to_layout = fx.layout_of(fx.monomorphize(to_ty));
 355                     match from_ty.kind {
 356                         ty::FnDef(def_id, substs) => {
 357                             let func_ref = fx.get_function_ref(
 358                                 Instance::resolve(fx.tcx, ParamEnv::reveal_all(), def_id, substs)
 359                                     .unwrap(),
 360                             );
 361                             let func_addr = fx.bcx.ins().func_addr(fx.pointer_type, func_ref);
 362                             lval.write_cvalue(fx, CValue::by_val(func_addr, to_layout));
 363                         }
 364                         _ => bug!("Trying to ReifyFnPointer on non FnDef {:?}", from_ty),
 365                     }
 366                 }
 367                 Rvalue::Cast(CastKind::Pointer(PointerCast::UnsafeFnPointer), operand, to_ty)
 368                 | Rvalue::Cast(CastKind::Pointer(PointerCast::MutToConstPointer), operand, to_ty)
 369                 | Rvalue::Cast(CastKind::Pointer(PointerCast::ArrayToPointer), operand, to_ty) => {
 370                     let to_layout = fx.layout_of(fx.monomorphize(to_ty));
 371                     let operand = trans_operand(fx, operand);
 372                     lval.write_cvalue(fx, operand.unchecked_cast_to(to_layout));
 373                 }
 374                 Rvalue::Cast(CastKind::Misc, operand, to_ty) => {
 375                     let operand = trans_operand(fx, operand);
 376                     let from_ty = operand.layout().ty;
 377                     let to_ty = fx.monomorphize(to_ty);
 378
 379                     fn is_fat_ptr<'tcx>(
 380                         fx: &FunctionCx<'_, 'tcx, impl Backend>,
 381                         ty: Ty<'tcx>,
 382                     ) -> bool {
 383                         ty.builtin_deref(true)
 384                             .map(
 385                                 |ty::TypeAndMut {
 386                                      ty: pointee_ty,
 387                                      mutbl: _,
 388                                  }| has_ptr_meta(fx.tcx, pointee_ty),
 389                             )
 390                             .unwrap_or(false)
 391                     }
 392
 393                     if is_fat_ptr(fx, from_ty) {
 394                         if is_fat_ptr(fx, to_ty) {
 395                             // fat-ptr -> fat-ptr
 396                             lval.write_cvalue(fx, operand.unchecked_cast_to(dest_layout));
 397                         } else {
 398                             // fat-ptr -> thin-ptr
 399                             let (ptr, _extra) = operand.load_scalar_pair(fx);
 400                             lval.write_cvalue(fx, CValue::by_val(ptr, dest_layout))
 401                         }
 402                     } else if let ty::Adt(adt_def, _substs) = from_ty.kind {
 403                         // enum -> discriminant value
 404                         assert!(adt_def.is_enum());
 405                         match to_ty.kind {
 406                             ty::Uint(_) | ty::Int(_) => {}
 407                             _ => unreachable!("cast adt {} -> {}", from_ty, to_ty),
 408                         }
 409
 410                         let discr = crate::discriminant::codegen_get_discriminant(
 411                             fx,
 412                             operand,
 413                             fx.layout_of(to_ty),
 414                         );
 415                         lval.write_cvalue(fx, discr);
 416                     } else {
 417                         let to_clif_ty = fx.clif_type(to_ty).unwrap();
 418                         let from = operand.load_scalar(fx);
 419
 420                         let res = clif_int_or_float_cast(
 421                             fx,
 422                             from,
 423                             type_sign(from_ty),
 424                             to_clif_ty,
 425                             type_sign(to_ty),
 426                         );
 427                         lval.write_cvalue(fx, CValue::by_val(res, dest_layout));
 428                     }
 429                 }
 430                 Rvalue::Cast(CastKind::Pointer(PointerCast::ClosureFnPointer(_)), operand, _to_ty) => {
 431                     let operand = trans_operand(fx, operand);
 432                     match operand.layout().ty.kind {
 433                         ty::Closure(def_id, substs) => {
 434                             let instance = Instance::resolve_closure(
 435                                 fx.tcx,
 436                                 def_id,
 437                                 substs,
 438                                 ty::ClosureKind::FnOnce,
 439                             );
 440                             let func_ref = fx.get_function_ref(instance);
 441                             let func_addr = fx.bcx.ins().func_addr(fx.pointer_type, func_ref);
 442                             lval.write_cvalue(fx, CValue::by_val(func_addr, lval.layout()));
 443                         }
 444                         _ => bug!("{} cannot be cast to a fn ptr", operand.layout().ty),
 445                     }
 446                 }
 447                 Rvalue::Cast(CastKind::Pointer(PointerCast::Unsize), operand, _to_ty) => {
 448                     let operand = trans_operand(fx, operand);
 449                     operand.unsize_value(fx, lval);
 450                 }
 451                 Rvalue::Discriminant(place) => {
 452                     let place = trans_place(fx, place);
 453                     let value = place.to_cvalue(fx);
 454                     let discr =
 455                         crate::discriminant::codegen_get_discriminant(fx, value, dest_layout);
 456                     lval.write_cvalue(fx, discr);
 457                 }
 458                 Rvalue::Repeat(operand, times) => {
 459                     let operand = trans_operand(fx, operand);
 460                     for i in 0..*times {
 461                         let index = fx.bcx.ins().iconst(fx.pointer_type, i as i64);
 462                         let to = lval.place_index(fx, index);
 463                         to.write_cvalue(fx, operand);
 464                     }
 465                 }
 466                 Rvalue::Len(place) => {
 467                     let place = trans_place(fx, place);
 468                     let usize_layout = fx.layout_of(fx.tcx.types.usize);
 469                     let len = codegen_array_len(fx, place);
 470                     lval.write_cvalue(fx, CValue::by_val(len, usize_layout));
 471                 }
 472                 Rvalue::NullaryOp(NullOp::Box, content_ty) => {
 473                     use rustc::middle::lang_items::ExchangeMallocFnLangItem;
 474
 475                     let usize_type = fx.clif_type(fx.tcx.types.usize).unwrap();
 476                     let content_ty = fx.monomorphize(content_ty);
 477                     let layout = fx.layout_of(content_ty);
 478                     let llsize = fx.bcx.ins().iconst(usize_type, layout.size.bytes() as i64);
 479                     let llalign = fx
 480                         .bcx
 481                         .ins()
 482                         .iconst(usize_type, layout.align.abi.bytes() as i64);
 483                     let box_layout = fx.layout_of(fx.tcx.mk_box(content_ty));
 484
 485                     // Allocate space:
 486                     let def_id = match fx.tcx.lang_items().require(ExchangeMallocFnLangItem) {
 487                         Ok(id) => id,
 488                         Err(s) => {
 489                             fx.tcx
 490                                 .sess
 491                                 .fatal(&format!("allocation of `{}` {}", box_layout.ty, s));
 492                         }
 493                     };
 494                     let instance = ty::Instance::mono(fx.tcx, def_id);
 495                     let func_ref = fx.get_function_ref(instance);
 496                     let call = fx.bcx.ins().call(func_ref, &[llsize, llalign]);
 497                     let ptr = fx.bcx.inst_results(call)[0];
 498                     lval.write_cvalue(fx, CValue::by_val(ptr, box_layout));
 499                 }
 500                 Rvalue::NullaryOp(NullOp::SizeOf, ty) => {
 501                     assert!(lval
 502                         .layout()
 503                         .ty
 504                         .is_sized(fx.tcx.at(stmt.source_info.span), ParamEnv::reveal_all()));
 505                     let ty_size = fx.layout_of(fx.monomorphize(ty)).size.bytes();
 506                     let val = CValue::const_val(fx, fx.tcx.types.usize, ty_size.into());
 507                     lval.write_cvalue(fx, val);
 508                 }
 509                 Rvalue::Aggregate(kind, operands) => match **kind {
 510                     AggregateKind::Array(_ty) => {
 511                         for (i, operand) in operands.into_iter().enumerate() {
 512                             let operand = trans_operand(fx, operand);
 513                             let index = fx.bcx.ins().iconst(fx.pointer_type, i as i64);
 514                             let to = lval.place_index(fx, index);
 515                             to.write_cvalue(fx, operand);
 516                         }
 517                     }
 518                     _ => unreachable!("shouldn't exist at trans {:?}", to_place_and_rval.1),
 519                 },
 520             }
 521         }
 522         StatementKind::StorageLive(_)
 523         | StatementKind::StorageDead(_)
 524         | StatementKind::Nop
 525         | StatementKind::FakeRead(..)
 526         | StatementKind::Retag { .. }
 527         | StatementKind::AscribeUserType(..) => {}
 528
 529         StatementKind::InlineAsm(asm) => {
 530             use syntax::ast::Name;
 531             let InlineAsm {
 532                 asm,
 533                 outputs: _,
 534                 inputs: _,
 535             } = &**asm;
 536             let rustc_hir::InlineAsmInner {
 537                 asm: asm_code, // Name
 538                 outputs,       // Vec<Name>
 539                 inputs,        // Vec<Name>
 540                 clobbers,      // Vec<Name>
 541                 volatile,      // bool
 542                 alignstack,    // bool
 543                 dialect: _,    // syntax::ast::AsmDialect
 544                 asm_str_style: _,
 545             } = asm;
 546             match &*asm_code.as_str() {
 547                 "" => {
 548                     assert_eq!(inputs, &[Name::intern("r")]);
 549                     assert!(outputs.is_empty(), "{:?}", outputs);
 550
 551                     // Black box
 552                 }
 553                 "cpuid" | "cpuid\n" => {
 554                     assert_eq!(inputs, &[Name::intern("{eax}"), Name::intern("{ecx}")]);
 555
 556                     assert_eq!(outputs.len(), 4);
 557                     for (i, c) in (&["={eax}", "={ebx}", "={ecx}", "={edx}"])
 558                         .iter()
 559                         .enumerate()
 560                     {
 561                         assert_eq!(&outputs[i].constraint.as_str(), c);
 562                         assert!(!outputs[i].is_rw);
 563                         assert!(!outputs[i].is_indirect);
 564                     }
 565
 566                     assert_eq!(clobbers, &[Name::intern("rbx")]);
 567
 568                     assert!(!volatile);
 569                     assert!(!alignstack);
 570
 571                     crate::trap::trap_unimplemented(
 572                         fx,
 573                         "__cpuid_count arch intrinsic is not supported",
 574                     );
 575                 }
 576                 "xgetbv" => {
 577                     assert_eq!(inputs, &[Name::intern("{ecx}")]);
 578
 579                     assert_eq!(outputs.len(), 2);
 580                     for (i, c) in (&["={eax}", "={edx}"]).iter().enumerate() {
 581                         assert_eq!(&outputs[i].constraint.as_str(), c);
 582                         assert!(!outputs[i].is_rw);
 583                         assert!(!outputs[i].is_indirect);
 584                     }
 585
 586                     assert_eq!(clobbers, &[]);
 587
 588                     assert!(!volatile);
 589                     assert!(!alignstack);
 590
 591                     crate::trap::trap_unimplemented(fx, "_xgetbv arch intrinsic is not supported");
 592                 }
 593                 _ if fx.tcx.symbol_name(fx.instance).name.as_str() == "__rust_probestack" => {
 594                     crate::trap::trap_unimplemented(fx, "__rust_probestack is not supported");
 595                 }
 596                 _ => unimpl!("Inline assembly is not supported"),
 597             }
 598         }
 599     }
 600 }
 601
 602 fn codegen_array_len<'tcx>(
 603     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
 604     place: CPlace<'tcx>,
 605 ) -> Value {
 606     match place.layout().ty.kind {
 607         ty::Array(_elem_ty, len) => {
 608             let len = crate::constant::force_eval_const(fx, len)
 609                 .eval_usize(fx.tcx, ParamEnv::reveal_all()) as i64;
 610             fx.bcx.ins().iconst(fx.pointer_type, len)
 611         }
 612         ty::Slice(_elem_ty) => place
 613             .to_ptr_maybe_unsized(fx)
 614             .1
 615             .expect("Length metadata for slice place"),
 616         _ => bug!("Rvalue::Len({:?})", place),
 617     }
 618 }
 619
 620 pub fn trans_place<'tcx>(
 621     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
 622     place: &Place<'tcx>,
 623 ) -> CPlace<'tcx> {
 624     let mut cplace = match &place.base {
 625         PlaceBase::Local(local) => fx.get_local_place(*local),
 626         PlaceBase::Static(static_) => match static_.kind {
 627             StaticKind::Static => {
 628                 // Statics can't be generic, so `static_.ty` doesn't need to be monomorphized.
 629                 crate::constant::codegen_static_ref(fx, static_.def_id, static_.ty)
 630             }
 631             StaticKind::Promoted(promoted, substs) => {
 632                 let instance = Instance::new(static_.def_id, fx.monomorphize(&substs));
 633                 let ty = fx.monomorphize(&static_.ty);
 634                 crate::constant::trans_promoted(fx, instance, promoted, ty)
 635             }
 636         },
 637     };
 638
 639     for elem in &*place.projection {
 640         match *elem {
 641             PlaceElem::Deref => {
 642                 cplace = cplace.place_deref(fx);
 643             }
 644             PlaceElem::Field(field, _ty) => {
 645                 cplace = cplace.place_field(fx, field);
 646             }
 647             PlaceElem::Index(local) => {
 648                 let index = fx.get_local_place(local).to_cvalue(fx).load_scalar(fx);
 649                 cplace = cplace.place_index(fx, index);
 650             }
 651             PlaceElem::ConstantIndex {
 652                 offset,
 653                 min_length: _,
 654                 from_end,
 655             } => {
 656                 let index = if !from_end {
 657                     fx.bcx.ins().iconst(fx.pointer_type, offset as i64)
 658                 } else {
 659                     let len = codegen_array_len(fx, cplace);
 660                     fx.bcx.ins().iadd_imm(len, -(offset as i64))
 661                 };
 662                 cplace = cplace.place_index(fx, index);
 663             }
 664             PlaceElem::Subslice { from, to, from_end } => {
 665                 // These indices are generated by slice patterns.
 666                 // slice[from:-to] in Python terms.
 667
 668                 match cplace.layout().ty.kind {
 669                     ty::Array(elem_ty, len) => {
 670                         let elem_layout = fx.layout_of(elem_ty);
 671                         let ptr = cplace.to_ptr(fx);
 672                         let len = crate::constant::force_eval_const(fx, len)
 673                             .eval_usize(fx.tcx, ParamEnv::reveal_all());
 674                         cplace = CPlace::for_ptr(
 675                             ptr.offset_i64(fx, elem_layout.size.bytes() as i64 * from as i64),
 676                             fx.layout_of(fx.tcx.mk_array(elem_ty, len - from as u64 - to as u64)),
 677                         );
 678                     }
 679                     ty::Slice(elem_ty) => {
 680                         assert!(from_end, "slice subslices should be `from_end`");
 681                         let elem_layout = fx.layout_of(elem_ty);
 682                         let (ptr, len) = cplace.to_ptr_maybe_unsized(fx);
 683                         let len = len.unwrap();
 684                         cplace = CPlace::for_ptr_with_extra(
 685                             ptr.offset_i64(fx, elem_layout.size.bytes() as i64 * from as i64),
 686                             fx.bcx.ins().iadd_imm(len, -(from as i64 + to as i64)),
 687                             cplace.layout(),
 688                         );
 689                     }
 690                     _ => unreachable!(),
 691                 }
 692             }
 693             PlaceElem::Downcast(_adt_def, variant) => {
 694                 cplace = cplace.downcast_variant(fx, variant);
 695             }
 696         }
 697     }
 698
 699     cplace
 700 }
 701
 702 pub fn trans_operand<'tcx>(
 703     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
 704     operand: &Operand<'tcx>,
 705 ) -> CValue<'tcx> {
 706     match operand {
 707         Operand::Move(place) | Operand::Copy(place) => {
 708             let cplace = trans_place(fx, place);
 709             cplace.to_cvalue(fx)
 710         }
 711         Operand::Constant(const_) => crate::constant::trans_constant(fx, const_),
 712     }
 713 }