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     let mut cold_ebbs = EntitySet::new();
  36     for (bb, &ebb) in ebb_map.iter_enumerated() {
  37         if mir.basic_blocks()[bb].is_cleanup {
  38             cold_ebbs.insert(ebb);
  39         }
  40     }
  41
  42     // Make FunctionCx
  43     let pointer_type = cx.module.target_config().pointer_type();
  44     let clif_comments = crate::pretty_clif::CommentWriter::new(tcx, instance);
  45
  46     let mut fx = FunctionCx {
  47         tcx,
  48         module: cx.module,
  49         pointer_type,
  50
  51         instance,
  52         mir,
  53
  54         bcx,
  55         ebb_map,
  56         local_map: HashMap::new(),
  57         caller_location: None, // set by `codegen_fn_prelude`
  58         cold_ebbs,
  59
  60         clif_comments,
  61         constants_cx: &mut cx.constants_cx,
  62         vtables: &mut cx.vtables,
  63         source_info_set: indexmap::IndexSet::new(),
  64     };
  65
  66     if fx.mir.args_iter().any(|arg| fx.layout_of(fx.monomorphize(&fx.mir.local_decls[arg].ty)).abi.is_uninhabited()) {
  67         let entry_block = fx.bcx.create_ebb();
  68         fx.bcx.append_ebb_params_for_function_params(entry_block);
  69         fx.bcx.switch_to_block(entry_block);
  70         crate::trap::trap_unreachable(&mut fx, "function has uninhabited argument");
  71     } else {
  72         tcx.sess.time("codegen clif ir", || {
  73             tcx.sess.time("codegen prelude", || crate::abi::codegen_fn_prelude(&mut fx, start_ebb));
  74             codegen_fn_content(&mut fx);
  75         });
  76     }
  77
  78     // Recover all necessary data from fx, before accessing func will prevent future access to it.
  79     let instance = fx.instance;
  80     let mut clif_comments = fx.clif_comments;
  81     let source_info_set = fx.source_info_set;
  82     let local_map = fx.local_map;
  83     let cold_ebbs = fx.cold_ebbs;
  84
  85     #[cfg(debug_assertions)]
  86     crate::pretty_clif::write_clif_file(cx.tcx, "unopt", instance, &context.func, &clif_comments, None);
  87
  88     // Verify function
  89     verify_func(tcx, &clif_comments, &context.func);
  90
  91     // Perform rust specific optimizations
  92     tcx.sess.time("optimize clif ir", || {
  93         crate::optimize::optimize_function(tcx, instance, context, &cold_ebbs, &mut clif_comments);
  94     });
  95
  96     // Define function
  97     let module = &mut cx.module;
  98     tcx.sess.time("define function", || module.define_function(func_id, context).unwrap());
  99
 100     // Write optimized function to file for debugging
 101     #[cfg(debug_assertions)]
 102     {
 103         let value_ranges = context
 104             .build_value_labels_ranges(cx.module.isa())
 105             .expect("value location ranges");
 106
 107         crate::pretty_clif::write_clif_file(
 108             cx.tcx,
 109             "opt",
 110             instance,
 111             &context.func,
 112             &clif_comments,
 113             Some(&value_ranges),
 114         );
 115     }
 116
 117     // Define debuginfo for function
 118     let isa = cx.module.isa();
 119     tcx.sess.time("generate debug info", || {
 120         debug_context
 121             .as_mut()
 122             .map(|x| x.define(context, isa, &source_info_set, local_map));
 123     });
 124
 125     // Clear context to make it usable for the next function
 126     context.clear();
 127 }
 128
 129 pub fn verify_func(tcx: TyCtxt, writer: &crate::pretty_clif::CommentWriter, func: &Function) {
 130     tcx.sess.time("verify clif ir", || {
 131         let flags = settings::Flags::new(settings::builder());
 132         match ::cranelift_codegen::verify_function(&func, &flags) {
 133             Ok(_) => {}
 134             Err(err) => {
 135                 tcx.sess.err(&format!("{:?}", err));
 136                 let pretty_error = ::cranelift_codegen::print_errors::pretty_verifier_error(
 137                     &func,
 138                     None,
 139                     Some(Box::new(writer)),
 140                     err,
 141                 );
 142                 tcx.sess
 143                     .fatal(&format!("cranelift verify error:\n{}", pretty_error));
 144             }
 145         }
 146     });
 147 }
 148
 149 fn codegen_fn_content(fx: &mut FunctionCx<'_, '_, impl Backend>) {
 150     for (bb, bb_data) in fx.mir.basic_blocks().iter_enumerated() {
 151         if bb_data.is_cleanup {
 152             // Unwinding after panicking is not supported
 153             continue;
 154         }
 155
 156         let ebb = fx.get_ebb(bb);
 157         fx.bcx.switch_to_block(ebb);
 158
 159         fx.bcx.ins().nop();
 160         for stmt in &bb_data.statements {
 161             fx.set_debug_loc(stmt.source_info);
 162             trans_stmt(fx, ebb, stmt);
 163         }
 164
 165         #[cfg(debug_assertions)]
 166         {
 167             let mut terminator_head = "\n".to_string();
 168             bb_data
 169                 .terminator()
 170                 .kind
 171                 .fmt_head(&mut terminator_head)
 172                 .unwrap();
 173             let inst = fx.bcx.func.layout.last_inst(ebb).unwrap();
 174             fx.add_comment(inst, terminator_head);
 175         }
 176
 177         fx.set_debug_loc(bb_data.terminator().source_info);
 178
 179         match &bb_data.terminator().kind {
 180             TerminatorKind::Goto { target } => {
 181                 let ebb = fx.get_ebb(*target);
 182                 fx.bcx.ins().jump(ebb, &[]);
 183             }
 184             TerminatorKind::Return => {
 185                 crate::abi::codegen_return(fx);
 186             }
 187             TerminatorKind::Assert {
 188                 cond,
 189                 expected,
 190                 msg,
 191                 target,
 192                 cleanup: _,
 193             } => {
 194                 if !fx.tcx.sess.overflow_checks() {
 195                     if let mir::interpret::PanicInfo::OverflowNeg = *msg {
 196                         let target = fx.get_ebb(*target);
 197                         fx.bcx.ins().jump(target, &[]);
 198                         continue;
 199                     }
 200                 }
 201                 let cond = trans_operand(fx, cond).load_scalar(fx);
 202
 203                 let target = fx.get_ebb(*target);
 204                 let failure = fx.bcx.create_ebb();
 205                 fx.cold_ebbs.insert(failure);
 206
 207                 if *expected {
 208                     fx.bcx.ins().brz(cond, failure, &[]);
 209                 } else {
 210                     fx.bcx.ins().brnz(cond, failure, &[]);
 211                 };
 212                 fx.bcx.ins().jump(target, &[]);
 213
 214                 fx.bcx.switch_to_block(failure);
 215                 trap_panic(
 216                     fx,
 217                     format!(
 218                         "[panic] Assert {:?} at {:?} failed.",
 219                         msg,
 220                         bb_data.terminator().source_info.span
 221                     ),
 222                 );
 223             }
 224
 225             TerminatorKind::SwitchInt {
 226                 discr,
 227                 switch_ty: _,
 228                 values,
 229                 targets,
 230             } => {
 231                 let discr = trans_operand(fx, discr).load_scalar(fx);
 232                 let mut switch = ::cranelift_frontend::Switch::new();
 233                 for (i, value) in values.iter().enumerate() {
 234                     let ebb = fx.get_ebb(targets[i]);
 235                     switch.set_entry(*value as u64, ebb);
 236                 }
 237                 let otherwise_ebb = fx.get_ebb(targets[targets.len() - 1]);
 238                 switch.emit(&mut fx.bcx, discr, otherwise_ebb);
 239             }
 240             TerminatorKind::Call {
 241                 func,
 242                 args,
 243                 destination,
 244                 cleanup: _,
 245                 from_hir_call: _,
 246             } => {
 247                 fx.tcx.sess.time("codegen call", || crate::abi::codegen_terminator_call(
 248                     fx,
 249                     bb_data.terminator().source_info.span,
 250                     func,
 251                     args,
 252                     destination,
 253                 ));
 254             }
 255             TerminatorKind::Resume | TerminatorKind::Abort => {
 256                 trap_unreachable(fx, "[corruption] Unwinding bb reached.");
 257             }
 258             TerminatorKind::Unreachable => {
 259                 trap_unreachable(fx, "[corruption] Hit unreachable code.");
 260             }
 261             TerminatorKind::Yield { .. }
 262             | TerminatorKind::FalseEdges { .. }
 263             | TerminatorKind::FalseUnwind { .. }
 264             | TerminatorKind::DropAndReplace { .. }
 265             | TerminatorKind::GeneratorDrop => {
 266                 bug!("shouldn't exist at trans {:?}", bb_data.terminator());
 267             }
 268             TerminatorKind::Drop {
 269                 location,
 270                 target,
 271                 unwind: _,
 272             } => {
 273                 let drop_place = trans_place(fx, location);
 274                 crate::abi::codegen_drop(fx, bb_data.terminator().source_info.span, drop_place);
 275
 276                 let target_ebb = fx.get_ebb(*target);
 277                 fx.bcx.ins().jump(target_ebb, &[]);
 278             }
 279         };
 280     }
 281
 282     fx.bcx.seal_all_blocks();
 283     fx.bcx.finalize();
 284 }
 285
 286 fn trans_stmt<'tcx>(
 287     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
 288     cur_ebb: Ebb,
 289     stmt: &Statement<'tcx>,
 290 ) {
 291     let _print_guard = PrintOnPanic(|| format!("stmt {:?}", stmt));
 292
 293     fx.set_debug_loc(stmt.source_info);
 294
 295     #[cfg(debug_assertions)]
 296     match &stmt.kind {
 297         StatementKind::StorageLive(..) | StatementKind::StorageDead(..) => {} // Those are not very useful
 298         _ => {
 299             let inst = fx.bcx.func.layout.last_inst(cur_ebb).unwrap();
 300             fx.add_comment(inst, format!("{:?}", stmt));
 301         }
 302     }
 303
 304     match &stmt.kind {
 305         StatementKind::SetDiscriminant {
 306             place,
 307             variant_index,
 308         } => {
 309             let place = trans_place(fx, place);
 310             crate::discriminant::codegen_set_discriminant(fx, place, *variant_index);
 311         }
 312         StatementKind::Assign(to_place_and_rval) => {
 313             let lval = trans_place(fx, &to_place_and_rval.0);
 314             let dest_layout = lval.layout();
 315             match &to_place_and_rval.1 {
 316                 Rvalue::Use(operand) => {
 317                     let val = trans_operand(fx, operand);
 318                     lval.write_cvalue(fx, val);
 319                 }
 320                 Rvalue::Ref(_, _, place) | Rvalue::AddressOf(_, place) => {
 321                     let place = trans_place(fx, place);
 322                     place.write_place_ref(fx, lval);
 323                 }
 324                 Rvalue::BinaryOp(bin_op, lhs, rhs) => {
 325                     let lhs = trans_operand(fx, lhs);
 326                     let rhs = trans_operand(fx, rhs);
 327
 328                     let res = crate::num::codegen_binop(fx, *bin_op, lhs, rhs);
 329                     lval.write_cvalue(fx, res);
 330                 }
 331                 Rvalue::CheckedBinaryOp(bin_op, lhs, rhs) => {
 332                     let lhs = trans_operand(fx, lhs);
 333                     let rhs = trans_operand(fx, rhs);
 334
 335                     let res = if !fx.tcx.sess.overflow_checks() {
 336                         let val =
 337                             crate::num::trans_int_binop(fx, *bin_op, lhs, rhs).load_scalar(fx);
 338                         let is_overflow = fx.bcx.ins().iconst(types::I8, 0);
 339                         CValue::by_val_pair(val, is_overflow, lval.layout())
 340                     } else {
 341                         crate::num::trans_checked_int_binop(fx, *bin_op, lhs, rhs)
 342                     };
 343
 344                     lval.write_cvalue(fx, res);
 345                 }
 346                 Rvalue::UnaryOp(un_op, operand) => {
 347                     let operand = trans_operand(fx, operand);
 348                     let layout = operand.layout();
 349                     let val = operand.load_scalar(fx);
 350                     let res = match un_op {
 351                         UnOp::Not => {
 352                             match layout.ty.kind {
 353                                 ty::Bool => {
 354                                     let val = fx.bcx.ins().uextend(types::I32, val); // WORKAROUND for CraneStation/cranelift#466
 355                                     let res = fx.bcx.ins().icmp_imm(IntCC::Equal, val, 0);
 356                                     CValue::by_val(fx.bcx.ins().bint(types::I8, res), layout)
 357                                 }
 358                                 ty::Uint(_) | ty::Int(_) => {
 359                                     CValue::by_val(fx.bcx.ins().bnot(val), layout)
 360                                 }
 361                                 _ => unimplemented!("un op Not for {:?}", layout.ty),
 362                             }
 363                         }
 364                         UnOp::Neg => match layout.ty.kind {
 365                             ty::Int(_) => {
 366                                 let zero = CValue::const_val(fx, layout.ty, 0);
 367                                 crate::num::trans_int_binop(fx, BinOp::Sub, zero, operand)
 368                             }
 369                             ty::Float(_) => {
 370                                 CValue::by_val(fx.bcx.ins().fneg(val), layout)
 371                             }
 372                             _ => unimplemented!("un op Neg for {:?}", layout.ty),
 373                         },
 374                     };
 375                     lval.write_cvalue(fx, res);
 376                 }
 377                 Rvalue::Cast(CastKind::Pointer(PointerCast::ReifyFnPointer), operand, to_ty) => {
 378                     let from_ty = fx.monomorphize(&operand.ty(&fx.mir.local_decls, fx.tcx));
 379                     let to_layout = fx.layout_of(fx.monomorphize(to_ty));
 380                     match from_ty.kind {
 381                         ty::FnDef(def_id, substs) => {
 382                             let func_ref = fx.get_function_ref(
 383                                 Instance::resolve_for_fn_ptr(fx.tcx, ParamEnv::reveal_all(), def_id, substs)
 384                                     .unwrap(),
 385                             );
 386                             let func_addr = fx.bcx.ins().func_addr(fx.pointer_type, func_ref);
 387                             lval.write_cvalue(fx, CValue::by_val(func_addr, to_layout));
 388                         }
 389                         _ => bug!("Trying to ReifyFnPointer on non FnDef {:?}", from_ty),
 390                     }
 391                 }
 392                 Rvalue::Cast(CastKind::Pointer(PointerCast::UnsafeFnPointer), operand, to_ty)
 393                 | Rvalue::Cast(CastKind::Pointer(PointerCast::MutToConstPointer), operand, to_ty)
 394                 | Rvalue::Cast(CastKind::Pointer(PointerCast::ArrayToPointer), operand, to_ty) => {
 395                     let to_layout = fx.layout_of(fx.monomorphize(to_ty));
 396                     let operand = trans_operand(fx, operand);
 397                     lval.write_cvalue(fx, operand.unchecked_cast_to(to_layout));
 398                 }
 399                 Rvalue::Cast(CastKind::Misc, operand, to_ty) => {
 400                     let operand = trans_operand(fx, operand);
 401                     let from_ty = operand.layout().ty;
 402                     let to_ty = fx.monomorphize(to_ty);
 403
 404                     fn is_fat_ptr<'tcx>(
 405                         fx: &FunctionCx<'_, 'tcx, impl Backend>,
 406                         ty: Ty<'tcx>,
 407                     ) -> bool {
 408                         ty.builtin_deref(true)
 409                             .map(
 410                                 |ty::TypeAndMut {
 411                                      ty: pointee_ty,
 412                                      mutbl: _,
 413                                  }| has_ptr_meta(fx.tcx, pointee_ty),
 414                             )
 415                             .unwrap_or(false)
 416                     }
 417
 418                     if is_fat_ptr(fx, from_ty) {
 419                         if is_fat_ptr(fx, to_ty) {
 420                             // fat-ptr -> fat-ptr
 421                             lval.write_cvalue(fx, operand.unchecked_cast_to(dest_layout));
 422                         } else {
 423                             // fat-ptr -> thin-ptr
 424                             let (ptr, _extra) = operand.load_scalar_pair(fx);
 425                             lval.write_cvalue(fx, CValue::by_val(ptr, dest_layout))
 426                         }
 427                     } else if let ty::Adt(adt_def, _substs) = from_ty.kind {
 428                         // enum -> discriminant value
 429                         assert!(adt_def.is_enum());
 430                         match to_ty.kind {
 431                             ty::Uint(_) | ty::Int(_) => {}
 432                             _ => unreachable!("cast adt {} -> {}", from_ty, to_ty),
 433                         }
 434
 435                         let discr = crate::discriminant::codegen_get_discriminant(
 436                             fx,
 437                             operand,
 438                             fx.layout_of(to_ty),
 439                         );
 440                         lval.write_cvalue(fx, discr);
 441                     } else {
 442                         let to_clif_ty = fx.clif_type(to_ty).unwrap();
 443                         let from = operand.load_scalar(fx);
 444
 445                         let res = clif_int_or_float_cast(
 446                             fx,
 447                             from,
 448                             type_sign(from_ty),
 449                             to_clif_ty,
 450                             type_sign(to_ty),
 451                         );
 452                         lval.write_cvalue(fx, CValue::by_val(res, dest_layout));
 453                     }
 454                 }
 455                 Rvalue::Cast(CastKind::Pointer(PointerCast::ClosureFnPointer(_)), operand, _to_ty) => {
 456                     let operand = trans_operand(fx, operand);
 457                     match operand.layout().ty.kind {
 458                         ty::Closure(def_id, substs) => {
 459                             let instance = Instance::resolve_closure(
 460                                 fx.tcx,
 461                                 def_id,
 462                                 substs,
 463                                 ty::ClosureKind::FnOnce,
 464                             );
 465                             let func_ref = fx.get_function_ref(instance);
 466                             let func_addr = fx.bcx.ins().func_addr(fx.pointer_type, func_ref);
 467                             lval.write_cvalue(fx, CValue::by_val(func_addr, lval.layout()));
 468                         }
 469                         _ => bug!("{} cannot be cast to a fn ptr", operand.layout().ty),
 470                     }
 471                 }
 472                 Rvalue::Cast(CastKind::Pointer(PointerCast::Unsize), operand, _to_ty) => {
 473                     let operand = trans_operand(fx, operand);
 474                     operand.unsize_value(fx, lval);
 475                 }
 476                 Rvalue::Discriminant(place) => {
 477                     let place = trans_place(fx, place);
 478                     let value = place.to_cvalue(fx);
 479                     let discr =
 480                         crate::discriminant::codegen_get_discriminant(fx, value, dest_layout);
 481                     lval.write_cvalue(fx, discr);
 482                 }
 483                 Rvalue::Repeat(operand, times) => {
 484                     let operand = trans_operand(fx, operand);
 485                     for i in 0..*times {
 486                         let index = fx.bcx.ins().iconst(fx.pointer_type, i as i64);
 487                         let to = lval.place_index(fx, index);
 488                         to.write_cvalue(fx, operand);
 489                     }
 490                 }
 491                 Rvalue::Len(place) => {
 492                     let place = trans_place(fx, place);
 493                     let usize_layout = fx.layout_of(fx.tcx.types.usize);
 494                     let len = codegen_array_len(fx, place);
 495                     lval.write_cvalue(fx, CValue::by_val(len, usize_layout));
 496                 }
 497                 Rvalue::NullaryOp(NullOp::Box, content_ty) => {
 498                     use rustc::middle::lang_items::ExchangeMallocFnLangItem;
 499
 500                     let usize_type = fx.clif_type(fx.tcx.types.usize).unwrap();
 501                     let content_ty = fx.monomorphize(content_ty);
 502                     let layout = fx.layout_of(content_ty);
 503                     let llsize = fx.bcx.ins().iconst(usize_type, layout.size.bytes() as i64);
 504                     let llalign = fx
 505                         .bcx
 506                         .ins()
 507                         .iconst(usize_type, layout.align.abi.bytes() as i64);
 508                     let box_layout = fx.layout_of(fx.tcx.mk_box(content_ty));
 509
 510                     // Allocate space:
 511                     let def_id = match fx.tcx.lang_items().require(ExchangeMallocFnLangItem) {
 512                         Ok(id) => id,
 513                         Err(s) => {
 514                             fx.tcx
 515                                 .sess
 516                                 .fatal(&format!("allocation of `{}` {}", box_layout.ty, s));
 517                         }
 518                     };
 519                     let instance = ty::Instance::mono(fx.tcx, def_id);
 520                     let func_ref = fx.get_function_ref(instance);
 521                     let call = fx.bcx.ins().call(func_ref, &[llsize, llalign]);
 522                     let ptr = fx.bcx.inst_results(call)[0];
 523                     lval.write_cvalue(fx, CValue::by_val(ptr, box_layout));
 524                 }
 525                 Rvalue::NullaryOp(NullOp::SizeOf, ty) => {
 526                     assert!(lval
 527                         .layout()
 528                         .ty
 529                         .is_sized(fx.tcx.at(stmt.source_info.span), ParamEnv::reveal_all()));
 530                     let ty_size = fx.layout_of(fx.monomorphize(ty)).size.bytes();
 531                     let val = CValue::const_val(fx, fx.tcx.types.usize, ty_size.into());
 532                     lval.write_cvalue(fx, val);
 533                 }
 534                 Rvalue::Aggregate(kind, operands) => match **kind {
 535                     AggregateKind::Array(_ty) => {
 536                         for (i, operand) in operands.into_iter().enumerate() {
 537                             let operand = trans_operand(fx, operand);
 538                             let index = fx.bcx.ins().iconst(fx.pointer_type, i as i64);
 539                             let to = lval.place_index(fx, index);
 540                             to.write_cvalue(fx, operand);
 541                         }
 542                     }
 543                     _ => unreachable!("shouldn't exist at trans {:?}", to_place_and_rval.1),
 544                 },
 545             }
 546         }
 547         StatementKind::StorageLive(_)
 548         | StatementKind::StorageDead(_)
 549         | StatementKind::Nop
 550         | StatementKind::FakeRead(..)
 551         | StatementKind::Retag { .. }
 552         | StatementKind::AscribeUserType(..) => {}
 553
 554         StatementKind::InlineAsm(asm) => {
 555             use syntax::ast::Name;
 556             let InlineAsm {
 557                 asm,
 558                 outputs: _,
 559                 inputs: _,
 560             } = &**asm;
 561             let rustc_hir::InlineAsmInner {
 562                 asm: asm_code, // Name
 563                 outputs,       // Vec<Name>
 564                 inputs,        // Vec<Name>
 565                 clobbers,      // Vec<Name>
 566                 volatile,      // bool
 567                 alignstack,    // bool
 568                 dialect: _,    // syntax::ast::AsmDialect
 569                 asm_str_style: _,
 570             } = asm;
 571             match &*asm_code.as_str() {
 572                 "" => {
 573                     assert_eq!(inputs, &[Name::intern("r")]);
 574                     assert!(outputs.is_empty(), "{:?}", outputs);
 575
 576                     // Black box
 577                 }
 578                 "cpuid" | "cpuid\n" => {
 579                     assert_eq!(inputs, &[Name::intern("{eax}"), Name::intern("{ecx}")]);
 580
 581                     assert_eq!(outputs.len(), 4);
 582                     for (i, c) in (&["={eax}", "={ebx}", "={ecx}", "={edx}"])
 583                         .iter()
 584                         .enumerate()
 585                     {
 586                         assert_eq!(&outputs[i].constraint.as_str(), c);
 587                         assert!(!outputs[i].is_rw);
 588                         assert!(!outputs[i].is_indirect);
 589                     }
 590
 591                     assert_eq!(clobbers, &[Name::intern("rbx")]);
 592
 593                     assert!(!volatile);
 594                     assert!(!alignstack);
 595
 596                     crate::trap::trap_unimplemented(
 597                         fx,
 598                         "__cpuid_count arch intrinsic is not supported",
 599                     );
 600                 }
 601                 "xgetbv" => {
 602                     assert_eq!(inputs, &[Name::intern("{ecx}")]);
 603
 604                     assert_eq!(outputs.len(), 2);
 605                     for (i, c) in (&["={eax}", "={edx}"]).iter().enumerate() {
 606                         assert_eq!(&outputs[i].constraint.as_str(), c);
 607                         assert!(!outputs[i].is_rw);
 608                         assert!(!outputs[i].is_indirect);
 609                     }
 610
 611                     assert_eq!(clobbers, &[]);
 612
 613                     assert!(!volatile);
 614                     assert!(!alignstack);
 615
 616                     crate::trap::trap_unimplemented(fx, "_xgetbv arch intrinsic is not supported");
 617                 }
 618                 _ if fx.tcx.symbol_name(fx.instance).name.as_str() == "__rust_probestack" => {
 619                     crate::trap::trap_unimplemented(fx, "__rust_probestack is not supported");
 620                 }
 621                 _ => unimpl!("Inline assembly is not supported"),
 622             }
 623         }
 624     }
 625 }
 626
 627 fn codegen_array_len<'tcx>(
 628     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
 629     place: CPlace<'tcx>,
 630 ) -> Value {
 631     match place.layout().ty.kind {
 632         ty::Array(_elem_ty, len) => {
 633             let len = crate::constant::force_eval_const(fx, len)
 634                 .eval_usize(fx.tcx, ParamEnv::reveal_all()) as i64;
 635             fx.bcx.ins().iconst(fx.pointer_type, len)
 636         }
 637         ty::Slice(_elem_ty) => place
 638             .to_ptr_maybe_unsized(fx)
 639             .1
 640             .expect("Length metadata for slice place"),
 641         _ => bug!("Rvalue::Len({:?})", place),
 642     }
 643 }
 644
 645 pub fn trans_place<'tcx>(
 646     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
 647     place: &Place<'tcx>,
 648 ) -> CPlace<'tcx> {
 649     let mut cplace = match &place.base {
 650         PlaceBase::Local(local) => fx.get_local_place(*local),
 651         PlaceBase::Static(static_) => match static_.kind {
 652             StaticKind::Static => {
 653                 // Statics can't be generic, so `static_.ty` doesn't need to be monomorphized.
 654                 crate::constant::codegen_static_ref(fx, static_.def_id, static_.ty)
 655             }
 656             StaticKind::Promoted(promoted, substs) => {
 657                 let instance = Instance::new(static_.def_id, fx.monomorphize(&substs));
 658                 let ty = fx.monomorphize(&static_.ty);
 659                 crate::constant::trans_promoted(fx, instance, promoted, ty)
 660             }
 661         },
 662     };
 663
 664     for elem in &*place.projection {
 665         match *elem {
 666             PlaceElem::Deref => {
 667                 cplace = cplace.place_deref(fx);
 668             }
 669             PlaceElem::Field(field, _ty) => {
 670                 cplace = cplace.place_field(fx, field);
 671             }
 672             PlaceElem::Index(local) => {
 673                 let index = fx.get_local_place(local).to_cvalue(fx).load_scalar(fx);
 674                 cplace = cplace.place_index(fx, index);
 675             }
 676             PlaceElem::ConstantIndex {
 677                 offset,
 678                 min_length: _,
 679                 from_end,
 680             } => {
 681                 let index = if !from_end {
 682                     fx.bcx.ins().iconst(fx.pointer_type, offset as i64)
 683                 } else {
 684                     let len = codegen_array_len(fx, cplace);
 685                     fx.bcx.ins().iadd_imm(len, -(offset as i64))
 686                 };
 687                 cplace = cplace.place_index(fx, index);
 688             }
 689             PlaceElem::Subslice { from, to, from_end } => {
 690                 // These indices are generated by slice patterns.
 691                 // slice[from:-to] in Python terms.
 692
 693                 match cplace.layout().ty.kind {
 694                     ty::Array(elem_ty, len) => {
 695                         let elem_layout = fx.layout_of(elem_ty);
 696                         let ptr = cplace.to_ptr(fx);
 697                         let len = crate::constant::force_eval_const(fx, len)
 698                             .eval_usize(fx.tcx, ParamEnv::reveal_all());
 699                         cplace = CPlace::for_ptr(
 700                             ptr.offset_i64(fx, elem_layout.size.bytes() as i64 * from as i64),
 701                             fx.layout_of(fx.tcx.mk_array(elem_ty, to as u64 - from as u64)),
 702                         );
 703                     }
 704                     ty::Slice(elem_ty) => {
 705                         assert!(from_end, "slice subslices should be `from_end`");
 706                         let elem_layout = fx.layout_of(elem_ty);
 707                         let (ptr, len) = cplace.to_ptr_maybe_unsized(fx);
 708                         let len = len.unwrap();
 709                         cplace = CPlace::for_ptr_with_extra(
 710                             ptr.offset_i64(fx, elem_layout.size.bytes() as i64 * from as i64),
 711                             fx.bcx.ins().iadd_imm(len, -(from as i64 + to as i64)),
 712                             cplace.layout(),
 713                         );
 714                     }
 715                     _ => unreachable!(),
 716                 }
 717             }
 718             PlaceElem::Downcast(_adt_def, variant) => {
 719                 cplace = cplace.downcast_variant(fx, variant);
 720             }
 721         }
 722     }
 723
 724     cplace
 725 }
 726
 727 pub fn trans_operand<'tcx>(
 728     fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
 729     operand: &Operand<'tcx>,
 730 ) -> CValue<'tcx> {
 731     match operand {
 732         Operand::Move(place) | Operand::Copy(place) => {
 733             let cplace = trans_place(fx, place);
 734             cplace.to_cvalue(fx)
 735         }
 736         Operand::Constant(const_) => crate::constant::trans_constant(fx, const_),
 737     }
 738 }