src/base.rs

   1 use rustc::ty::adjustment::PointerCast;
   2
   3 use crate::prelude::*;
   4
   5 pub fn trans_fn<'clif, 'tcx, B: Backend + 'static>(
   6     cx: &mut crate::CodegenCx<'clif, 'tcx, B>,
   7     instance: Instance<'tcx>,
   8     linkage: Linkage,
   9 ) {
  10     let tcx = cx.tcx;
  11
  12     let mir = *tcx.instance_mir(instance.def);
  13
  14     // Declare function
  15     let (name, sig) = get_function_name_and_sig(tcx, cx.module.isa().triple(), instance, false);
  16     let func_id = cx.module.declare_function(&name, linkage, &sig).unwrap();
  17     let mut debug_context = cx
  18         .debug_context
  19         .as_mut()
  20         .map(|debug_context| FunctionDebugContext::new(debug_context, instance, func_id, &name));
  21
  22     // Make FunctionBuilder
  23     let mut func = Function::with_name_signature(ExternalName::user(0, 0), sig);
  24     func.collect_debug_info();
  25     let mut func_ctx = FunctionBuilderContext::new();
  26     let mut bcx = FunctionBuilder::new(&mut func, &mut func_ctx);
  27
  28     // Predefine ebb's
  29     let start_ebb = bcx.create_ebb();
  30     let mut ebb_map: HashMap<BasicBlock, Ebb> = HashMap::new();
  31     for (bb, _bb_data) in mir.basic_blocks().iter_enumerated() {
  32         ebb_map.insert(bb, bcx.create_ebb());
  33     }
  34
  35     // Make FunctionCx
  36     let pointer_type = cx.module.target_config().pointer_type();
  37     let clif_comments = crate::pretty_clif::CommentWriter::new(tcx, instance);
  38
  39     let mut fx = FunctionCx {
  40         tcx,
  41         module: cx.module,
  42         pointer_type,
  43
  44         instance,
  45         mir,
  46
  47         bcx,
  48         ebb_map,
  49         local_map: HashMap::new(),
  50
  51         clif_comments,
  52         constants_cx: &mut cx.constants_cx,
  53         caches: &mut cx.caches,
  54         source_info_set: indexmap::IndexSet::new(),
  55     };
  56
  57     if fx.mir.args_iter().any(|arg| fx.layout_of(fx.monomorphize(&fx.mir.local_decls[arg].ty)).abi.is_uninhabited()) {
  58         let entry_block = fx.bcx.create_ebb();
  59         fx.bcx.append_ebb_params_for_function_params(entry_block);
  60         fx.bcx.switch_to_block(entry_block);
  61         crate::trap::trap_unreachable(&mut fx, "function has uninhabited argument");
  62     } else {
  63         crate::abi::codegen_fn_prelude(&mut fx, start_ebb);
  64         codegen_fn_content(&mut fx);
  65     }
  66
  67     // Recover all necessary data from fx, before accessing func will prevent future access to it.
  68     let instance = fx.instance;
  69     let mut clif_comments = fx.clif_comments;
  70     let source_info_set = fx.source_info_set;
  71     let local_map = fx.local_map;
  72
  73     #[cfg(debug_assertions)]
  74     crate::pretty_clif::write_clif_file(cx.tcx, "unopt", instance, &func, &clif_comments, None);
  75
  76     // Verify function
  77     verify_func(tcx, &clif_comments, &func);
  78
  79     let context = &mut cx.caches.context;
  80     context.func = func;
  81
  82     // Perform rust specific optimizations
  83     crate::optimize::optimize_function(cx.tcx, instance, context, &mut clif_comments);
  84
  85     // Define function
  86     cx.module.define_function(func_id, context).unwrap();
  87
  88     // Write optimized function to file for debugging
  89     #[cfg(debug_assertions)]
  90     {
  91         let value_ranges = context
  92             .build_value_labels_ranges(cx.module.isa())
  93             .expect("value location ranges");
  94
  95         crate::pretty_clif::write_clif_file(
  96             cx.tcx,
  97             "opt",
  98             instance,
  99             &context.func,
 100             &clif_comments,
 101             Some(&value_ranges),
 102         );
 103     }
 104
 105     // Define debuginfo for function
 106     let isa = cx.module.isa();
 107     debug_context
 108         .as_mut()
 109         .map(|x| x.define(context, isa, &source_info_set, local_map));
 110
 111     // Clear context to make it usable for the next function
 112     context.clear();
 113 }
 114
 115 pub fn verify_func(tcx: TyCtxt, writer: &crate::pretty_clif::CommentWriter, func: &Function) {
 116     let flags = settings::Flags::new(settings::builder());
 117     match ::cranelift_codegen::verify_function(&func, &flags) {
 118         Ok(_) => {}
 119         Err(err) => {
 120             tcx.sess.err(&format!("{:?}", err));
 121             let pretty_error = ::cranelift_codegen::print_errors::pretty_verifier_error(
 122                 &func,
 123                 None,
 124                 Some(Box::new(writer)),
 125                 err,
 126             );
 127             tcx.sess
 128                 .fatal(&format!("cranelift verify error:\n{}", pretty_error));
 129         }
 130     }
 131 }
 132
 133 fn codegen_fn_content(fx: &mut FunctionCx<'_, '_, impl Backend>) {
 134     for (bb, bb_data) in fx.mir.basic_blocks().iter_enumerated() {
 135         if bb_data.is_cleanup {
 136             // Unwinding after panicking is not supported
 137             continue;
 138         }
 139
 140         let ebb = fx.get_ebb(bb);
 141         fx.bcx.switch_to_block(ebb);
 142
 143         fx.bcx.ins().nop();
 144         for stmt in &bb_data.statements {
 145             fx.set_debug_loc(stmt.source_info);
 146             trans_stmt(fx, ebb, stmt);
 147         }
 148
 149         #[cfg(debug_assertions)]
 150         {
 151             let mut terminator_head = "\n".to_string();
 152             bb_data
 153                 .terminator()
 154                 .kind
 155                 .fmt_head(&mut terminator_head)
 156                 .unwrap();
 157             let inst = fx.bcx.func.layout.last_inst(ebb).unwrap();
 158             fx.add_comment(inst, terminator_head);
 159         }
 160
 161         fx.set_debug_loc(bb_data.terminator().source_info);
 162
 163         match &bb_data.terminator().kind {
 164             TerminatorKind::Goto { target } => {
 165                 let ebb = fx.get_ebb(*target);
 166                 fx.bcx.ins().jump(ebb, &[]);
 167             }
 168             TerminatorKind::Return => {
 169                 crate::abi::codegen_return(fx);
 170             }
 171             TerminatorKind::Assert {
 172                 cond,
 173                 expected,
 174                 msg,
 175                 target,
 176                 cleanup: _,
 177             } => {
 178                 if !fx.tcx.sess.overflow_checks() {
 179                     if let mir::interpret::PanicInfo::OverflowNeg = *msg {
 180                         let target = fx.get_ebb(*target);
 181                         fx.bcx.ins().jump(target, &[]);
 182                         continue;
 183                     }
 184                 }
 185                 let cond = trans_operand(fx, cond).load_scalar(fx);
 186                 let target = fx.get_ebb(*target);
 187                 if *expected {
 188                     fx.bcx.ins().brnz(cond, target, &[]);
 189                 } else {
 190                     fx.bcx.ins().brz(cond, target, &[]);
 191                 };
 192                 trap_panic(
 193                     fx,
 194                     format!(
 195                         "[panic] Assert {:?} at {:?} failed.",
 196                         msg,
 197                         bb_data.terminator().source_info.span
 198                     ),
 199                 );
 200             }
 201
 202             TerminatorKind::SwitchInt {
 203                 discr,
 204                 switch_ty: _,
 205                 values,
 206                 targets,
 207             } => {
 208                 let discr = trans_operand(fx, discr).load_scalar(fx);
 209                 let mut switch = ::cranelift_frontend::Switch::new();
 210                 for (i, value) in values.iter().enumerate() {
 211                     let ebb = fx.get_ebb(targets[i]);
 212                     switch.set_entry(*value as u64, ebb);
 213                 }
 214                 let otherwise_ebb = fx.get_ebb(targets[targets.len() - 1]);
 215                 switch.emit(&mut fx.bcx, discr, otherwise_ebb);
 216             }
 217             TerminatorKind::Call {
 218                 func,
 219                 args,
 220                 destination,
 221                 cleanup: _,
 222                 from_hir_call: _,
 223             } => {
 224                 crate::abi::codegen_terminator_call(
 225                     fx,
 226                     func,
 227                     args,
 228                     destination,
 229                     bb_data.terminator().source_info.span,
 230                 );
 231             }
 232             TerminatorKind::Resume | TerminatorKind::Abort => {
 233                 trap_unreachable(fx, "[corruption] Unwinding bb reached.");
 234             }
 235             TerminatorKind::Unreachable => {
 236                 trap_unreachable(fx, "[corruption] Hit unreachable code.");
 237             }
 238             TerminatorKind::Yield { .. }
 239             | TerminatorKind::FalseEdges { .. }
 240             | TerminatorKind::FalseUnwind { .. }
 241             | TerminatorKind::DropAndReplace { .. }
 242             | TerminatorKind::GeneratorDrop => {
 243                 bug!("shouldn't exist at trans {:?}", bb_data.terminator());
 244             }
 245             TerminatorKind::Drop {
 246                 location,
 247                 target,
 248                 unwind: _,
 249             } => {
 250                 let drop_place = trans_place(fx, location);
 251                 crate::abi::codegen_drop(fx, drop_place);
 252
 253                 let target_ebb = fx.get_ebb(*target);
 254                 fx.bcx.ins().jump(target_ebb, &[]);
 255             }
 256         };
 257     }
 258
 259     fx.bcx.seal_all_blocks();
 260     fx.bcx.finalize();
 261 }
 262
 263 fn trans_stmt<'tcx>(
 264     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
 265     cur_ebb: Ebb,
 266     stmt: &Statement<'tcx>,
 267 ) {
 268     let _print_guard = PrintOnPanic(|| format!("stmt {:?}", stmt));
 269
 270     fx.set_debug_loc(stmt.source_info);
 271
 272     #[cfg(false_debug_assertions)]
 273     match &stmt.kind {
 274         StatementKind::StorageLive(..) | StatementKind::StorageDead(..) => {} // Those are not very useful
 275         _ => {
 276             let inst = fx.bcx.func.layout.last_inst(cur_ebb).unwrap();
 277             fx.add_comment(inst, format!("{:?}", stmt));
 278         }
 279     }
 280
 281     match &stmt.kind {
 282         StatementKind::SetDiscriminant {
 283             place,
 284             variant_index,
 285         } => {
 286             let place = trans_place(fx, place);
 287             crate::discriminant::codegen_set_discriminant(fx, place, *variant_index);
 288         }
 289         StatementKind::Assign(to_place_and_rval) => {
 290             let lval = trans_place(fx, &to_place_and_rval.0);
 291             let dest_layout = lval.layout();
 292             match &to_place_and_rval.1 {
 293                 Rvalue::Use(operand) => {
 294                     let val = trans_operand(fx, operand);
 295                     lval.write_cvalue(fx, val);
 296                 }
 297                 Rvalue::Ref(_, _, place) | Rvalue::AddressOf(_, place) => {
 298                     let place = trans_place(fx, place);
 299                     place.write_place_ref(fx, lval);
 300                 }
 301                 Rvalue::BinaryOp(bin_op, lhs, rhs) => {
 302                     let lhs = trans_operand(fx, lhs);
 303                     let rhs = trans_operand(fx, rhs);
 304
 305                     let res = crate::num::codegen_binop(fx, *bin_op, lhs, rhs);
 306                     lval.write_cvalue(fx, res);
 307                 }
 308                 Rvalue::CheckedBinaryOp(bin_op, lhs, rhs) => {
 309                     let lhs = trans_operand(fx, lhs);
 310                     let rhs = trans_operand(fx, rhs);
 311
 312                     let res = if !fx.tcx.sess.overflow_checks() {
 313                         let val =
 314                             crate::num::trans_int_binop(fx, *bin_op, lhs, rhs).load_scalar(fx);
 315                         let is_overflow = fx.bcx.ins().iconst(types::I8, 0);
 316                         CValue::by_val_pair(val, is_overflow, lval.layout())
 317                     } else {
 318                         crate::num::trans_checked_int_binop(fx, *bin_op, lhs, rhs)
 319                     };
 320
 321                     lval.write_cvalue(fx, res);
 322                 }
 323                 Rvalue::UnaryOp(un_op, operand) => {
 324                     let operand = trans_operand(fx, operand);
 325                     let layout = operand.layout();
 326                     let val = operand.load_scalar(fx);
 327                     let res = match un_op {
 328                         UnOp::Not => {
 329                             match layout.ty.kind {
 330                                 ty::Bool => {
 331                                     let val = fx.bcx.ins().uextend(types::I32, val); // WORKAROUND for CraneStation/cranelift#466
 332                                     let res = fx.bcx.ins().icmp_imm(IntCC::Equal, val, 0);
 333                                     CValue::by_val(fx.bcx.ins().bint(types::I8, res), layout)
 334                                 }
 335                                 ty::Uint(_) | ty::Int(_) => {
 336                                     CValue::by_val(fx.bcx.ins().bnot(val), layout)
 337                                 }
 338                                 _ => unimplemented!("un op Not for {:?}", layout.ty),
 339                             }
 340                         }
 341                         UnOp::Neg => match layout.ty.kind {
 342                             ty::Int(_) => {
 343                                 let zero = CValue::const_val(fx, layout.ty, 0);
 344                                 crate::num::trans_int_binop(fx, BinOp::Sub, zero, operand)
 345                             }
 346                             ty::Float(_) => {
 347                                 CValue::by_val(fx.bcx.ins().fneg(val), layout)
 348                             }
 349                             _ => unimplemented!("un op Neg for {:?}", layout.ty),
 350                         },
 351                     };
 352                     lval.write_cvalue(fx, res);
 353                 }
 354                 Rvalue::Cast(CastKind::Pointer(PointerCast::ReifyFnPointer), operand, to_ty) => {
 355                     let from_ty = fx.monomorphize(&operand.ty(&fx.mir.local_decls, fx.tcx));
 356                     let to_layout = fx.layout_of(fx.monomorphize(to_ty));
 357                     match from_ty.kind {
 358                         ty::FnDef(def_id, substs) => {
 359                             let func_ref = fx.get_function_ref(
 360                                 Instance::resolve(fx.tcx, ParamEnv::reveal_all(), def_id, substs)
 361                                     .unwrap(),
 362                             );
 363                             let func_addr = fx.bcx.ins().func_addr(fx.pointer_type, func_ref);
 364                             lval.write_cvalue(fx, CValue::by_val(func_addr, to_layout));
 365                         }
 366                         _ => bug!("Trying to ReifyFnPointer on non FnDef {:?}", from_ty),
 367                     }
 368                 }
 369                 Rvalue::Cast(CastKind::Pointer(PointerCast::UnsafeFnPointer), operand, to_ty)
 370                 | Rvalue::Cast(CastKind::Pointer(PointerCast::MutToConstPointer), operand, to_ty)
 371                 | Rvalue::Cast(CastKind::Pointer(PointerCast::ArrayToPointer), operand, to_ty) => {
 372                     let to_layout = fx.layout_of(fx.monomorphize(to_ty));
 373                     let operand = trans_operand(fx, operand);
 374                     lval.write_cvalue(fx, operand.unchecked_cast_to(to_layout));
 375                 }
 376                 Rvalue::Cast(CastKind::Misc, operand, to_ty) => {
 377                     let operand = trans_operand(fx, operand);
 378                     let from_ty = operand.layout().ty;
 379                     let to_ty = fx.monomorphize(to_ty);
 380
 381                     fn is_fat_ptr<'tcx>(
 382                         fx: &FunctionCx<'_, 'tcx, impl Backend>,
 383                         ty: Ty<'tcx>,
 384                     ) -> bool {
 385                         ty.builtin_deref(true)
 386                             .map(
 387                                 |ty::TypeAndMut {
 388                                      ty: pointee_ty,
 389                                      mutbl: _,
 390                                  }| has_ptr_meta(fx.tcx, pointee_ty),
 391                             )
 392                             .unwrap_or(false)
 393                     }
 394
 395                     if is_fat_ptr(fx, from_ty) {
 396                         if is_fat_ptr(fx, to_ty) {
 397                             // fat-ptr -> fat-ptr
 398                             lval.write_cvalue(fx, operand.unchecked_cast_to(dest_layout));
 399                         } else {
 400                             // fat-ptr -> thin-ptr
 401                             let (ptr, _extra) = operand.load_scalar_pair(fx);
 402                             lval.write_cvalue(fx, CValue::by_val(ptr, dest_layout))
 403                         }
 404                     } else if let ty::Adt(adt_def, _substs) = from_ty.kind {
 405                         // enum -> discriminant value
 406                         assert!(adt_def.is_enum());
 407                         match to_ty.kind {
 408                             ty::Uint(_) | ty::Int(_) => {}
 409                             _ => unreachable!("cast adt {} -> {}", from_ty, to_ty),
 410                         }
 411
 412                         let discr = crate::discriminant::codegen_get_discriminant(
 413                             fx,
 414                             operand,
 415                             fx.layout_of(to_ty),
 416                         );
 417                         lval.write_cvalue(fx, discr);
 418                     } else {
 419                         let to_clif_ty = fx.clif_type(to_ty).unwrap();
 420                         let from = operand.load_scalar(fx);
 421
 422                         let res = clif_int_or_float_cast(
 423                             fx,
 424                             from,
 425                             type_sign(from_ty),
 426                             to_clif_ty,
 427                             type_sign(to_ty),
 428                         );
 429                         lval.write_cvalue(fx, CValue::by_val(res, dest_layout));
 430                     }
 431                 }
 432                 Rvalue::Cast(CastKind::Pointer(PointerCast::ClosureFnPointer(_)), operand, _to_ty) => {
 433                     let operand = trans_operand(fx, operand);
 434                     match operand.layout().ty.kind {
 435                         ty::Closure(def_id, substs) => {
 436                             let instance = Instance::resolve_closure(
 437                                 fx.tcx,
 438                                 def_id,
 439                                 substs,
 440                                 ty::ClosureKind::FnOnce,
 441                             );
 442                             let func_ref = fx.get_function_ref(instance);
 443                             let func_addr = fx.bcx.ins().func_addr(fx.pointer_type, func_ref);
 444                             lval.write_cvalue(fx, CValue::by_val(func_addr, lval.layout()));
 445                         }
 446                         _ => bug!("{} cannot be cast to a fn ptr", operand.layout().ty),
 447                     }
 448                 }
 449                 Rvalue::Cast(CastKind::Pointer(PointerCast::Unsize), operand, _to_ty) => {
 450                     let operand = trans_operand(fx, operand);
 451                     operand.unsize_value(fx, lval);
 452                 }
 453                 Rvalue::Discriminant(place) => {
 454                     let place = trans_place(fx, place);
 455                     let value = place.to_cvalue(fx);
 456                     let discr =
 457                         crate::discriminant::codegen_get_discriminant(fx, value, dest_layout);
 458                     lval.write_cvalue(fx, discr);
 459                 }
 460                 Rvalue::Repeat(operand, times) => {
 461                     let operand = trans_operand(fx, operand);
 462                     for i in 0..*times {
 463                         let index = fx.bcx.ins().iconst(fx.pointer_type, i as i64);
 464                         let to = lval.place_index(fx, index);
 465                         to.write_cvalue(fx, operand);
 466                     }
 467                 }
 468                 Rvalue::Len(place) => {
 469                     let place = trans_place(fx, place);
 470                     let usize_layout = fx.layout_of(fx.tcx.types.usize);
 471                     let len = codegen_array_len(fx, place);
 472                     lval.write_cvalue(fx, CValue::by_val(len, usize_layout));
 473                 }
 474                 Rvalue::NullaryOp(NullOp::Box, content_ty) => {
 475                     use rustc::middle::lang_items::ExchangeMallocFnLangItem;
 476
 477                     let usize_type = fx.clif_type(fx.tcx.types.usize).unwrap();
 478                     let content_ty = fx.monomorphize(content_ty);
 479                     let layout = fx.layout_of(content_ty);
 480                     let llsize = fx.bcx.ins().iconst(usize_type, layout.size.bytes() as i64);
 481                     let llalign = fx
 482                         .bcx
 483                         .ins()
 484                         .iconst(usize_type, layout.align.abi.bytes() as i64);
 485                     let box_layout = fx.layout_of(fx.tcx.mk_box(content_ty));
 486
 487                     // Allocate space:
 488                     let def_id = match fx.tcx.lang_items().require(ExchangeMallocFnLangItem) {
 489                         Ok(id) => id,
 490                         Err(s) => {
 491                             fx.tcx
 492                                 .sess
 493                                 .fatal(&format!("allocation of `{}` {}", box_layout.ty, s));
 494                         }
 495                     };
 496                     let instance = ty::Instance::mono(fx.tcx, def_id);
 497                     let func_ref = fx.get_function_ref(instance);
 498                     let call = fx.bcx.ins().call(func_ref, &[llsize, llalign]);
 499                     let ptr = fx.bcx.inst_results(call)[0];
 500                     lval.write_cvalue(fx, CValue::by_val(ptr, box_layout));
 501                 }
 502                 Rvalue::NullaryOp(NullOp::SizeOf, ty) => {
 503                     assert!(lval
 504                         .layout()
 505                         .ty
 506                         .is_sized(fx.tcx.at(DUMMY_SP), ParamEnv::reveal_all()));
 507                     let ty_size = fx.layout_of(fx.monomorphize(ty)).size.bytes();
 508                     let val = CValue::const_val(fx, fx.tcx.types.usize, ty_size.into());
 509                     lval.write_cvalue(fx, val);
 510                 }
 511                 Rvalue::Aggregate(kind, operands) => match **kind {
 512                     AggregateKind::Array(_ty) => {
 513                         for (i, operand) in operands.into_iter().enumerate() {
 514                             let operand = trans_operand(fx, operand);
 515                             let index = fx.bcx.ins().iconst(fx.pointer_type, i as i64);
 516                             let to = lval.place_index(fx, index);
 517                             to.write_cvalue(fx, operand);
 518                         }
 519                     }
 520                     _ => unreachable!("shouldn't exist at trans {:?}", to_place_and_rval.1),
 521                 },
 522             }
 523         }
 524         StatementKind::StorageLive(_)
 525         | StatementKind::StorageDead(_)
 526         | StatementKind::Nop
 527         | StatementKind::FakeRead(..)
 528         | StatementKind::Retag { .. }
 529         | StatementKind::AscribeUserType(..) => {}
 530
 531         StatementKind::InlineAsm(asm) => {
 532             use syntax::ast::Name;
 533             let InlineAsm {
 534                 asm,
 535                 outputs: _,
 536                 inputs: _,
 537             } = &**asm;
 538             let rustc::hir::InlineAsmInner {
 539                 asm: asm_code, // Name
 540                 outputs,       // Vec<Name>
 541                 inputs,        // Vec<Name>
 542                 clobbers,      // Vec<Name>
 543                 volatile,      // bool
 544                 alignstack,    // bool
 545                 dialect: _,    // syntax::ast::AsmDialect
 546                 asm_str_style: _,
 547             } = asm;
 548             match &*asm_code.as_str() {
 549                 "" => {
 550                     assert_eq!(inputs, &[Name::intern("r")]);
 551                     assert!(outputs.is_empty(), "{:?}", outputs);
 552
 553                     // Black box
 554                 }
 555                 "cpuid" | "cpuid\n" => {
 556                     assert_eq!(inputs, &[Name::intern("{eax}"), Name::intern("{ecx}")]);
 557
 558                     assert_eq!(outputs.len(), 4);
 559                     for (i, c) in (&["={eax}", "={ebx}", "={ecx}", "={edx}"])
 560                         .iter()
 561                         .enumerate()
 562                     {
 563                         assert_eq!(&outputs[i].constraint.as_str(), c);
 564                         assert!(!outputs[i].is_rw);
 565                         assert!(!outputs[i].is_indirect);
 566                     }
 567
 568                     assert_eq!(clobbers, &[Name::intern("rbx")]);
 569
 570                     assert!(!volatile);
 571                     assert!(!alignstack);
 572
 573                     crate::trap::trap_unimplemented(
 574                         fx,
 575                         "__cpuid_count arch intrinsic is not supported",
 576                     );
 577                 }
 578                 "xgetbv" => {
 579                     assert_eq!(inputs, &[Name::intern("{ecx}")]);
 580
 581                     assert_eq!(outputs.len(), 2);
 582                     for (i, c) in (&["={eax}", "={edx}"]).iter().enumerate() {
 583                         assert_eq!(&outputs[i].constraint.as_str(), c);
 584                         assert!(!outputs[i].is_rw);
 585                         assert!(!outputs[i].is_indirect);
 586                     }
 587
 588                     assert_eq!(clobbers, &[]);
 589
 590                     assert!(!volatile);
 591                     assert!(!alignstack);
 592
 593                     crate::trap::trap_unimplemented(fx, "_xgetbv arch intrinsic is not supported");
 594                 }
 595                 _ if fx.tcx.symbol_name(fx.instance).name.as_str() == "__rust_probestack" => {
 596                     crate::trap::trap_unimplemented(fx, "__rust_probestack is not supported");
 597                 }
 598                 _ => unimpl!("Inline assembly is not supported"),
 599             }
 600         }
 601     }
 602 }
 603
 604 fn codegen_array_len<'tcx>(
 605     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
 606     place: CPlace<'tcx>,
 607 ) -> Value {
 608     match place.layout().ty.kind {
 609         ty::Array(_elem_ty, len) => {
 610             let len = crate::constant::force_eval_const(fx, len)
 611                 .eval_usize(fx.tcx, ParamEnv::reveal_all()) as i64;
 612             fx.bcx.ins().iconst(fx.pointer_type, len)
 613         }
 614         ty::Slice(_elem_ty) => place
 615             .to_ptr_maybe_unsized(fx)
 616             .1
 617             .expect("Length metadata for slice place"),
 618         _ => bug!("Rvalue::Len({:?})", place),
 619     }
 620 }
 621
 622 pub fn trans_place<'tcx>(
 623     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
 624     place: &Place<'tcx>,
 625 ) -> CPlace<'tcx> {
 626     let mut cplace = match &place.base {
 627         PlaceBase::Local(local) => fx.get_local_place(*local),
 628         PlaceBase::Static(static_) => match static_.kind {
 629             StaticKind::Static => {
 630                 // Statics can't be generic, so `static_.ty` doesn't need to be monomorphized.
 631                 crate::constant::codegen_static_ref(fx, static_.def_id, static_.ty)
 632             }
 633             StaticKind::Promoted(promoted, substs) => {
 634                 let instance = Instance::new(static_.def_id, fx.monomorphize(&substs));
 635                 let ty = fx.monomorphize(&static_.ty);
 636                 crate::constant::trans_promoted(fx, instance, promoted, ty)
 637             }
 638         },
 639     };
 640
 641     for elem in &*place.projection {
 642         match *elem {
 643             PlaceElem::Deref => {
 644                 cplace = cplace.place_deref(fx);
 645             }
 646             PlaceElem::Field(field, _ty) => {
 647                 cplace = cplace.place_field(fx, field);
 648             }
 649             PlaceElem::Index(local) => {
 650                 let index = fx.get_local_place(local).to_cvalue(fx).load_scalar(fx);
 651                 cplace = cplace.place_index(fx, index);
 652             }
 653             PlaceElem::ConstantIndex {
 654                 offset,
 655                 min_length: _,
 656                 from_end,
 657             } => {
 658                 let index = if !from_end {
 659                     fx.bcx.ins().iconst(fx.pointer_type, offset as i64)
 660                 } else {
 661                     let len = codegen_array_len(fx, cplace);
 662                     fx.bcx.ins().iadd_imm(len, -(offset as i64))
 663                 };
 664                 cplace = cplace.place_index(fx, index);
 665             }
 666             PlaceElem::Subslice { from, to, from_end } => {
 667                 // These indices are generated by slice patterns.
 668                 // slice[from:-to] in Python terms.
 669
 670                 match cplace.layout().ty.kind {
 671                     ty::Array(elem_ty, len) => {
 672                         let elem_layout = fx.layout_of(elem_ty);
 673                         let ptr = cplace.to_ptr(fx);
 674                         let len = crate::constant::force_eval_const(fx, len)
 675                             .eval_usize(fx.tcx, ParamEnv::reveal_all());
 676                         cplace = CPlace::for_ptr(
 677                             ptr.offset_i64(fx, elem_layout.size.bytes() as i64 * from as i64),
 678                             fx.layout_of(fx.tcx.mk_array(elem_ty, len - from as u64 - to as u64)),
 679                         );
 680                     }
 681                     ty::Slice(elem_ty) => {
 682                         assert!(from_end, "slice subslices should be `from_end`");
 683                         let elem_layout = fx.layout_of(elem_ty);
 684                         let (ptr, len) = cplace.to_ptr_maybe_unsized(fx);
 685                         let len = len.unwrap();
 686                         cplace = CPlace::for_ptr_with_extra(
 687                             ptr.offset_i64(fx, elem_layout.size.bytes() as i64 * from as i64),
 688                             fx.bcx.ins().iadd_imm(len, -(from as i64 + to as i64)),
 689                             cplace.layout(),
 690                         );
 691                     }
 692                     _ => unreachable!(),
 693                 }
 694             }
 695             PlaceElem::Downcast(_adt_def, variant) => {
 696                 cplace = cplace.downcast_variant(fx, variant);
 697             }
 698         }
 699     }
 700
 701     cplace
 702 }
 703
 704 pub fn trans_operand<'tcx>(
 705     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
 706     operand: &Operand<'tcx>,
 707 ) -> CValue<'tcx> {
 708     match operand {
 709         Operand::Move(place) | Operand::Copy(place) => {
 710             let cplace = trans_place(fx, place);
 711             cplace.to_cvalue(fx)
 712         }
 713         Operand::Constant(const_) => crate::constant::trans_constant(fx, const_),
 714     }
 715 }