src/intrinsics.rs

   1 use crate::prelude::*;
   2
   3 use rustc::ty::subst::SubstsRef;
   4
   5 macro_rules! intrinsic_pat {
   6     (_) => {
   7         _
   8     };
   9     ($name:ident) => {
  10         stringify!($name)
  11     }
  12 }
  13
  14 macro_rules! intrinsic_arg {
  15     (c $fx:expr, $arg:ident) => {
  16         $arg
  17     };
  18     (v $fx:expr, $arg:ident) => {
  19         $arg.load_scalar($fx)
  20     };
  21 }
  22
  23 macro_rules! intrinsic_substs {
  24     ($substs:expr, $index:expr,) => {};
  25     ($substs:expr, $index:expr, $first:ident $(,$rest:ident)*) => {
  26         let $first = $substs.type_at($index);
  27         intrinsic_substs!($substs, $index+1, $($rest),*);
  28     };
  29 }
  30
  31 macro_rules! intrinsic_match {
  32     ($fx:expr, $intrinsic:expr, $substs:expr, $args:expr, $(
  33         $($name:tt)|+ $(if $cond:expr)?, $(<$($subst:ident),*>)? ($($a:ident $arg:ident),*) $content:block;
  34     )*) => {
  35         match $intrinsic {
  36             $(
  37                 $(intrinsic_pat!($name))|* $(if $cond)? => {
  38                     #[allow(unused_parens, non_snake_case)]
  39                     {
  40                         $(
  41                             intrinsic_substs!($substs, 0, $($subst),*);
  42                         )?
  43                         if let [$($arg),*] = *$args {
  44                             let ($($arg),*) = (
  45                                 $(intrinsic_arg!($a $fx, $arg)),*
  46                             );
  47                             #[warn(unused_parens, non_snake_case)]
  48                             {
  49                                 $content
  50                             }
  51                         } else {
  52                             bug!("wrong number of args for intrinsic {:?}", $intrinsic);
  53                         }
  54                     }
  55                 }
  56             )*
  57             _ => unimpl!("unsupported intrinsic {}", $intrinsic),
  58         }
  59     };
  60 }
  61
  62 macro_rules! atomic_binop_return_old {
  63     ($fx:expr, $op:ident<$T:ident>($ptr:ident, $src:ident) -> $ret:ident) => {
  64         let clif_ty = $fx.clif_type($T).unwrap();
  65         let old = $fx.bcx.ins().load(clif_ty, MemFlags::new(), $ptr, 0);
  66         let new = $fx.bcx.ins().$op(old, $src);
  67         $fx.bcx.ins().store(MemFlags::new(), new, $ptr, 0);
  68         $ret.write_cvalue($fx, CValue::by_val(old, $fx.layout_of($T)));
  69     };
  70 }
  71
  72 macro_rules! atomic_minmax {
  73     ($fx:expr, $cc:expr, <$T:ident> ($ptr:ident, $src:ident) -> $ret:ident) => {
  74         // Read old
  75         let clif_ty = $fx.clif_type($T).unwrap();
  76         let old = $fx.bcx.ins().load(clif_ty, MemFlags::new(), $ptr, 0);
  77
  78         // Compare
  79         let is_eq = $fx.bcx.ins().icmp(IntCC::SignedGreaterThan, old, $src);
  80         let new = crate::common::codegen_select(&mut $fx.bcx, is_eq, old, $src);
  81
  82         // Write new
  83         $fx.bcx.ins().store(MemFlags::new(), new, $ptr, 0);
  84
  85         let ret_val = CValue::by_val(old, $ret.layout());
  86         $ret.write_cvalue($fx, ret_val);
  87     };
  88 }
  89
  90 pub fn codegen_intrinsic_call<'a, 'tcx: 'a>(
  91     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
  92     def_id: DefId,
  93     substs: SubstsRef<'tcx>,
  94     args: Vec<CValue<'tcx>>,
  95     destination: Option<(CPlace<'tcx>, BasicBlock)>,
  96 ) {
  97     let intrinsic = fx.tcx.item_name(def_id).as_str();
  98     let intrinsic = &intrinsic[..];
  99
 100     let ret = match destination {
 101         Some((place, _)) => place,
 102         None => {
 103             // Insert non returning intrinsics here
 104             match intrinsic {
 105                 "abort" => {
 106                     trap_panic(fx, "Called intrinisc::abort.");
 107                 }
 108                 "unreachable" => {
 109                     trap_unreachable(fx, "[corruption] Called intrinsic::unreachable.");
 110                 }
 111                 _ => unimplemented!("unsupported instrinsic {}", intrinsic),
 112             }
 113             return;
 114         }
 115     };
 116
 117     let u64_layout = fx.layout_of(fx.tcx.types.u64);
 118     let usize_layout = fx.layout_of(fx.tcx.types.usize);
 119
 120     intrinsic_match! {
 121         fx, intrinsic, substs, args,
 122
 123         assume, (c _a) {};
 124         likely | unlikely, (c a) {
 125             ret.write_cvalue(fx, a);
 126         };
 127         breakpoint, () {
 128             fx.bcx.ins().debugtrap();
 129         };
 130         copy | copy_nonoverlapping, <elem_ty> (v src, v dst, v count) {
 131             let elem_size: u64 = fx.layout_of(elem_ty).size.bytes();
 132             let elem_size = fx
 133                 .bcx
 134                 .ins()
 135                 .iconst(fx.pointer_type, elem_size as i64);
 136             assert_eq!(args.len(), 3);
 137             let byte_amount = fx.bcx.ins().imul(count, elem_size);
 138
 139             if intrinsic.ends_with("_nonoverlapping") {
 140                 fx.bcx.call_memcpy(fx.module.target_config(), dst, src, byte_amount);
 141             } else {
 142                 fx.bcx.call_memmove(fx.module.target_config(), dst, src, byte_amount);
 143             }
 144         };
 145         discriminant_value, (c val) {
 146             let pointee_layout = fx.layout_of(val.layout().ty.builtin_deref(true).unwrap().ty);
 147             let place = CPlace::for_addr(val.load_scalar(fx), pointee_layout);
 148             let discr = crate::base::trans_get_discriminant(fx, place, ret.layout());
 149             ret.write_cvalue(fx, discr);
 150         };
 151         size_of, <T> () {
 152             let size_of = fx.layout_of(T).size.bytes();
 153             let size_of = CValue::const_val(fx, usize_layout.ty, size_of as i64);
 154             ret.write_cvalue(fx, size_of);
 155         };
 156         size_of_val, <T> (c ptr) {
 157             let layout = fx.layout_of(T);
 158             let size = if layout.is_unsized() {
 159                 let (_ptr, info) = ptr.load_scalar_pair(fx);
 160                 let (size, _align) = crate::unsize::size_and_align_of_dst(fx, layout.ty, info);
 161                 size
 162             } else {
 163                 fx
 164                     .bcx
 165                     .ins()
 166                     .iconst(fx.pointer_type, layout.size.bytes() as i64)
 167             };
 168             ret.write_cvalue(fx, CValue::by_val(size, usize_layout));
 169         };
 170         min_align_of, <T> () {
 171             let min_align = fx.layout_of(T).align.abi.bytes();
 172             let min_align = CValue::const_val(fx, usize_layout.ty, min_align as i64);
 173             ret.write_cvalue(fx, min_align);
 174         };
 175         min_align_of_val, <T> (c ptr) {
 176             let layout = fx.layout_of(T);
 177             let align = if layout.is_unsized() {
 178                 let (_ptr, info) = ptr.load_scalar_pair(fx);
 179                 let (_size, align) = crate::unsize::size_and_align_of_dst(fx, layout.ty, info);
 180                 align
 181             } else {
 182                 fx
 183                     .bcx
 184                     .ins()
 185                     .iconst(fx.pointer_type, layout.align.abi.bytes() as i64)
 186             };
 187             ret.write_cvalue(fx, CValue::by_val(align, usize_layout));
 188         };
 189         type_id, <T> () {
 190             let type_id = fx.tcx.type_id_hash(T);
 191             let type_id = CValue::const_val(fx, u64_layout.ty, type_id as i64);
 192             ret.write_cvalue(fx, type_id);
 193         };
 194         _ if intrinsic.starts_with("unchecked_") || intrinsic == "exact_div", (c x, c y) {
 195             // FIXME trap on overflow
 196             let bin_op = match intrinsic {
 197                 "unchecked_sub" => BinOp::Sub,
 198                 "unchecked_div" | "exact_div" => BinOp::Div,
 199                 "unchecked_rem" => BinOp::Rem,
 200                 "unchecked_shl" => BinOp::Shl,
 201                 "unchecked_shr" => BinOp::Shr,
 202                 _ => unimplemented!("intrinsic {}", intrinsic),
 203             };
 204             let res = match ret.layout().ty.sty {
 205                 ty::Uint(_) => crate::base::trans_int_binop(
 206                     fx,
 207                     bin_op,
 208                     x,
 209                     y,
 210                     ret.layout().ty,
 211                     false,
 212                 ),
 213                 ty::Int(_) => crate::base::trans_int_binop(
 214                     fx,
 215                     bin_op,
 216                     x,
 217                     y,
 218                     ret.layout().ty,
 219                     true,
 220                 ),
 221                 _ => panic!(),
 222             };
 223             ret.write_cvalue(fx, res);
 224         };
 225         _ if intrinsic.ends_with("_with_overflow"), <T> (c x, c y) {
 226             assert_eq!(x.layout().ty, y.layout().ty);
 227             let bin_op = match intrinsic {
 228                 "add_with_overflow" => BinOp::Add,
 229                 "sub_with_overflow" => BinOp::Sub,
 230                 "mul_with_overflow" => BinOp::Mul,
 231                 _ => unimplemented!("intrinsic {}", intrinsic),
 232             };
 233             let res = match T.sty {
 234                 ty::Uint(_) => crate::base::trans_checked_int_binop(
 235                     fx,
 236                     bin_op,
 237                     x,
 238                     y,
 239                     ret.layout().ty,
 240                     false,
 241                 ),
 242                 ty::Int(_) => crate::base::trans_checked_int_binop(
 243                     fx,
 244                     bin_op,
 245                     x,
 246                     y,
 247                     ret.layout().ty,
 248                     true,
 249                 ),
 250                 _ => panic!(),
 251             };
 252             ret.write_cvalue(fx, res);
 253         };
 254         _ if intrinsic.starts_with("overflowing_"), <T> (c x, c y) {
 255             assert_eq!(x.layout().ty, y.layout().ty);
 256             let bin_op = match intrinsic {
 257                 "overflowing_add" => BinOp::Add,
 258                 "overflowing_sub" => BinOp::Sub,
 259                 "overflowing_mul" => BinOp::Mul,
 260                 _ => unimplemented!("intrinsic {}", intrinsic),
 261             };
 262             let res = match T.sty {
 263                 ty::Uint(_) => crate::base::trans_int_binop(
 264                     fx,
 265                     bin_op,
 266                     x,
 267                     y,
 268                     ret.layout().ty,
 269                     false,
 270                 ),
 271                 ty::Int(_) => crate::base::trans_int_binop(
 272                     fx,
 273                     bin_op,
 274                     x,
 275                     y,
 276                     ret.layout().ty,
 277                     true,
 278                 ),
 279                 _ => panic!(),
 280             };
 281             ret.write_cvalue(fx, res);
 282         };
 283         _ if intrinsic.starts_with("saturating_"), <T> (c x, c y) {
 284             // FIXME implement saturating behavior
 285             assert_eq!(x.layout().ty, y.layout().ty);
 286             let bin_op = match intrinsic {
 287                 "saturating_add" => BinOp::Add,
 288                 "saturating_sub" => BinOp::Sub,
 289                 "saturating_mul" => BinOp::Mul,
 290                 _ => unimplemented!("intrinsic {}", intrinsic),
 291             };
 292             let res = match T.sty {
 293                 ty::Uint(_) => crate::base::trans_int_binop(
 294                     fx,
 295                     bin_op,
 296                     x,
 297                     y,
 298                     ret.layout().ty,
 299                     false,
 300                 ),
 301                 ty::Int(_) => crate::base::trans_int_binop(
 302                     fx,
 303                     bin_op,
 304                     x,
 305                     y,
 306                     ret.layout().ty,
 307                     true,
 308                 ),
 309                 _ => panic!(),
 310             };
 311             ret.write_cvalue(fx, res);
 312         };
 313         rotate_left, <T>(v x, v y) {
 314             let layout = fx.layout_of(T);
 315             let res = fx.bcx.ins().rotl(x, y);
 316             ret.write_cvalue(fx, CValue::by_val(res, layout));
 317         };
 318         rotate_right, <T>(v x, v y) {
 319             let layout = fx.layout_of(T);
 320             let res = fx.bcx.ins().rotr(x, y);
 321             ret.write_cvalue(fx, CValue::by_val(res, layout));
 322         };
 323
 324         // The only difference between offset and arith_offset is regarding UB. Because Cranelift
 325         // doesn't have UB both are codegen'ed the same way
 326         offset | arith_offset, (c base, v offset) {
 327             let pointee_ty = base.layout().ty.builtin_deref(true).unwrap().ty;
 328             let pointee_size = fx.layout_of(pointee_ty).size.bytes();
 329             let ptr_diff = fx.bcx.ins().imul_imm(offset, pointee_size as i64);
 330             let base_val = base.load_scalar(fx);
 331             let res = fx.bcx.ins().iadd(base_val, ptr_diff);
 332             ret.write_cvalue(fx, CValue::by_val(res, args[0].layout()));
 333         };
 334
 335         transmute, <src_ty, dst_ty> (c from) {
 336             assert_eq!(from.layout().ty, src_ty);
 337             let addr = from.force_stack(fx);
 338             let dst_layout = fx.layout_of(dst_ty);
 339             ret.write_cvalue(fx, CValue::by_ref(addr, dst_layout))
 340         };
 341         init, () {
 342             if ret.layout().abi == Abi::Uninhabited {
 343                 crate::trap::trap_panic(fx, "[panic] Called intrinsic::init for uninhabited type.");
 344                 return;
 345             }
 346
 347             match ret {
 348                 CPlace::NoPlace(_layout) => {}
 349                 CPlace::Var(var, layout) => {
 350                     let clif_ty = fx.clif_type(layout.ty).unwrap();
 351                     let val = match clif_ty {
 352                         types::I8 | types::I16 | types::I32 | types::I64 => fx.bcx.ins().iconst(clif_ty, 0),
 353                         types::F32 => {
 354                             let zero = fx.bcx.ins().iconst(types::I32, 0);
 355                             fx.bcx.ins().bitcast(types::F32, zero)
 356                         }
 357                         types::F64 => {
 358                             let zero = fx.bcx.ins().iconst(types::I64, 0);
 359                             fx.bcx.ins().bitcast(types::F64, zero)
 360                         }
 361                         _ => panic!("clif_type returned {}", clif_ty),
 362                     };
 363                     fx.bcx.def_var(mir_var(var), val);
 364                 }
 365                 _ => {
 366                     let addr = ret.to_addr(fx);
 367                     let layout = ret.layout();
 368                     fx.bcx.emit_small_memset(fx.module.target_config(), addr, 0, layout.size.bytes(), 1);
 369                 }
 370             }
 371         };
 372         write_bytes, (c dst, v val, v count) {
 373             let pointee_ty = dst.layout().ty.builtin_deref(true).unwrap().ty;
 374             let pointee_size = fx.layout_of(pointee_ty).size.bytes();
 375             let count = fx.bcx.ins().imul_imm(count, pointee_size as i64);
 376             let dst_ptr = dst.load_scalar(fx);
 377             fx.bcx.call_memset(fx.module.target_config(), dst_ptr, val, count);
 378         };
 379         uninit, <T> () {
 380             if ret.layout().abi == Abi::Uninhabited {
 381                 crate::trap::trap_panic(fx, "[panic] Called intrinsic::uninit for uninhabited type.");
 382                 return;
 383             }
 384
 385             let uninit_place = CPlace::new_stack_slot(fx, T);
 386             let uninit_val = uninit_place.to_cvalue(fx);
 387             ret.write_cvalue(fx, uninit_val);
 388         };
 389         ctlz | ctlz_nonzero, <T> (v arg) {
 390             let res = CValue::by_val(fx.bcx.ins().clz(arg), fx.layout_of(T));
 391             ret.write_cvalue(fx, res);
 392         };
 393         cttz | cttz_nonzero, <T> (v arg) {
 394             let res = CValue::by_val(fx.bcx.ins().ctz(arg), fx.layout_of(T));
 395             ret.write_cvalue(fx, res);
 396         };
 397         ctpop, <T> (v arg) {
 398             let res = CValue::by_val(fx.bcx.ins().popcnt(arg), fx.layout_of(T));
 399             ret.write_cvalue(fx, res);
 400         };
 401         bitreverse, <T> (v arg) {
 402             let res = CValue::by_val(fx.bcx.ins().bitrev(arg), fx.layout_of(T));
 403             ret.write_cvalue(fx, res);
 404         };
 405         needs_drop, <T> () {
 406             let needs_drop = if T.needs_drop(fx.tcx, ParamEnv::reveal_all()) {
 407                 1
 408             } else {
 409                 0
 410             };
 411             let needs_drop = CValue::const_val(fx, fx.tcx.types.bool, needs_drop);
 412             ret.write_cvalue(fx, needs_drop);
 413         };
 414         panic_if_uninhabited, <T> () {
 415             if fx.layout_of(T).abi.is_uninhabited() {
 416                 crate::trap::trap_panic(fx, "[panic] Called intrinsic::panic_if_uninhabited for uninhabited type.");
 417                 return;
 418             }
 419         };
 420
 421         _ if intrinsic.starts_with("atomic_fence"), () {};
 422         _ if intrinsic.starts_with("atomic_singlethreadfence"), () {};
 423         _ if intrinsic.starts_with("atomic_load"), (c ptr) {
 424             let inner_layout =
 425                 fx.layout_of(ptr.layout().ty.builtin_deref(true).unwrap().ty);
 426             let val = CValue::by_ref(ptr.load_scalar(fx), inner_layout);
 427             ret.write_cvalue(fx, val);
 428         };
 429         _ if intrinsic.starts_with("atomic_store"), (v ptr, c val) {
 430             let dest = CPlace::for_addr(ptr, val.layout());
 431             dest.write_cvalue(fx, val);
 432         };
 433         _ if intrinsic.starts_with("atomic_xchg"), <T> (v ptr, c src) {
 434             // Read old
 435             let clif_ty = fx.clif_type(T).unwrap();
 436             let old = fx.bcx.ins().load(clif_ty, MemFlags::new(), ptr, 0);
 437             ret.write_cvalue(fx, CValue::by_val(old, fx.layout_of(T)));
 438
 439             // Write new
 440             let dest = CPlace::for_addr(ptr, src.layout());
 441             dest.write_cvalue(fx, src);
 442         };
 443         _ if intrinsic.starts_with("atomic_cxchg"), <T> (v ptr, v test_old, v new) { // both atomic_cxchg_* and atomic_cxchgweak_*
 444             // Read old
 445             let clif_ty = fx.clif_type(T).unwrap();
 446             let old = fx.bcx.ins().load(clif_ty, MemFlags::new(), ptr, 0);
 447
 448             // Compare
 449             let is_eq = fx.bcx.ins().icmp(IntCC::Equal, old, test_old);
 450             let new = crate::common::codegen_select(&mut fx.bcx, is_eq, new, old); // Keep old if not equal to test_old
 451
 452             // Write new
 453             fx.bcx.ins().store(MemFlags::new(), new, ptr, 0);
 454
 455             let ret_val = CValue::by_val_pair(old, fx.bcx.ins().bint(types::I8, is_eq), ret.layout());
 456             ret.write_cvalue(fx, ret_val);
 457         };
 458
 459         _ if intrinsic.starts_with("atomic_xadd"), <T> (v ptr, v amount) {
 460             atomic_binop_return_old! (fx, iadd<T>(ptr, amount) -> ret);
 461         };
 462         _ if intrinsic.starts_with("atomic_xsub"), <T> (v ptr, v amount) {
 463             atomic_binop_return_old! (fx, isub<T>(ptr, amount) -> ret);
 464         };
 465         _ if intrinsic.starts_with("atomic_and"), <T> (v ptr, v src) {
 466             atomic_binop_return_old! (fx, band<T>(ptr, src) -> ret);
 467         };
 468         _ if intrinsic.starts_with("atomic_nand"), <T> (v ptr, v src) {
 469             atomic_binop_return_old! (fx, band_not<T>(ptr, src) -> ret);
 470         };
 471         _ if intrinsic.starts_with("atomic_or"), <T> (v ptr, v src) {
 472             atomic_binop_return_old! (fx, bor<T>(ptr, src) -> ret);
 473         };
 474         _ if intrinsic.starts_with("atomic_xor"), <T> (v ptr, v src) {
 475             atomic_binop_return_old! (fx, bxor<T>(ptr, src) -> ret);
 476         };
 477
 478         _ if intrinsic.starts_with("atomic_max"), <T> (v ptr, v src) {
 479             atomic_minmax!(fx, IntCC::SignedGreaterThan, <T> (ptr, src) -> ret);
 480         };
 481         _ if intrinsic.starts_with("atomic_umax"), <T> (v ptr, v src) {
 482             atomic_minmax!(fx, IntCC::UnsignedGreaterThan, <T> (ptr, src) -> ret);
 483         };
 484         _ if intrinsic.starts_with("atomic_min"), <T> (v ptr, v src) {
 485             atomic_minmax!(fx, IntCC::SignedLessThan, <T> (ptr, src) -> ret);
 486         };
 487         _ if intrinsic.starts_with("atomic_umin"), <T> (v ptr, v src) {
 488             atomic_minmax!(fx, IntCC::UnsignedLessThan, <T> (ptr, src) -> ret);
 489         };
 490     }
 491
 492     if let Some((_, dest)) = destination {
 493         let ret_ebb = fx.get_ebb(dest);
 494         fx.bcx.ins().jump(ret_ebb, &[]);
 495     } else {
 496         trap_unreachable(fx, "[corruption] Diverging intrinsic returned.");
 497     }
 498 }