src/shims/intrinsics.rs

   1 use std::iter;
   2
   3 use log::trace;
   4
   5 use rustc_apfloat::{Float, Round};
   6 use rustc_middle::ty::layout::{IntegerExt, LayoutOf};
   7 use rustc_middle::{mir, mir::BinOp, ty, ty::FloatTy};
   8 use rustc_target::abi::{Align, Integer};
   9
  10 use crate::*;
  11 use helpers::{bool_to_simd_element, check_arg_count, simd_element_to_bool};
  12
  13 pub enum AtomicOp {
  14     MirOp(mir::BinOp, bool),
  15     Max,
  16     Min,
  17 }
  18
  19 impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
  20 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
  21     fn call_intrinsic(
  22         &mut self,
  23         instance: ty::Instance<'tcx>,
  24         args: &[OpTy<'tcx, Tag>],
  25         ret: Option<(&PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
  26         _unwind: StackPopUnwind,
  27     ) -> InterpResult<'tcx> {
  28         let this = self.eval_context_mut();
  29
  30         if this.emulate_intrinsic(instance, args, ret)? {
  31             return Ok(());
  32         }
  33
  34         // All supported intrinsics have a return place.
  35         let intrinsic_name = this.tcx.item_name(instance.def_id());
  36         let intrinsic_name = intrinsic_name.as_str();
  37         let (dest, ret) = match ret {
  38             None => throw_unsup_format!("unimplemented (diverging) intrinsic: {}", intrinsic_name),
  39             Some(p) => p,
  40         };
  41
  42         // Then handle terminating intrinsics.
  43         match intrinsic_name {
  44             // Miri overwriting CTFE intrinsics.
  45             "ptr_guaranteed_eq" => {
  46                 let &[ref left, ref right] = check_arg_count(args)?;
  47                 let left = this.read_immediate(left)?;
  48                 let right = this.read_immediate(right)?;
  49                 this.binop_ignore_overflow(mir::BinOp::Eq, &left, &right, dest)?;
  50             }
  51             "ptr_guaranteed_ne" => {
  52                 let &[ref left, ref right] = check_arg_count(args)?;
  53                 let left = this.read_immediate(left)?;
  54                 let right = this.read_immediate(right)?;
  55                 this.binop_ignore_overflow(mir::BinOp::Ne, &left, &right, dest)?;
  56             }
  57             "const_allocate" => {
  58                 // For now, for compatibility with the run-time implementation of this, we just return null.
  59                 // See <https://github.com/rust-lang/rust/issues/93935>.
  60                 this.write_null(dest)?;
  61             }
  62             "const_deallocate" => {
  63                 // complete NOP
  64             }
  65
  66             // Raw memory accesses
  67             "volatile_load" => {
  68                 let &[ref place] = check_arg_count(args)?;
  69                 let place = this.deref_operand(place)?;
  70                 this.copy_op(&place.into(), dest)?;
  71             }
  72             "volatile_store" => {
  73                 let &[ref place, ref dest] = check_arg_count(args)?;
  74                 let place = this.deref_operand(place)?;
  75                 this.copy_op(dest, &place.into())?;
  76             }
  77
  78             "write_bytes" | "volatile_set_memory" => {
  79                 let &[ref ptr, ref val_byte, ref count] = check_arg_count(args)?;
  80                 let ty = instance.substs.type_at(0);
  81                 let ty_layout = this.layout_of(ty)?;
  82                 let val_byte = this.read_scalar(val_byte)?.to_u8()?;
  83                 let ptr = this.read_pointer(ptr)?;
  84                 let count = this.read_scalar(count)?.to_machine_usize(this)?;
  85                 let byte_count = ty_layout.size.checked_mul(count, this).ok_or_else(|| {
  86                     err_ub_format!("overflow computing total size of `{}`", intrinsic_name)
  87                 })?;
  88                 this.memory
  89                     .write_bytes(ptr, iter::repeat(val_byte).take(byte_count.bytes() as usize))?;
  90             }
  91
  92             // Floating-point operations
  93             #[rustfmt::skip]
  94             | "sinf32"
  95             | "fabsf32"
  96             | "cosf32"
  97             | "sqrtf32"
  98             | "expf32"
  99             | "exp2f32"
 100             | "logf32"
 101             | "log10f32"
 102             | "log2f32"
 103             | "floorf32"
 104             | "ceilf32"
 105             | "truncf32"
 106             | "roundf32"
 107             => {
 108                 let &[ref f] = check_arg_count(args)?;
 109                 // FIXME: Using host floats.
 110                 let f = f32::from_bits(this.read_scalar(f)?.to_u32()?);
 111                 let f = match intrinsic_name {
 112                     "sinf32" => f.sin(),
 113                     "fabsf32" => f.abs(),
 114                     "cosf32" => f.cos(),
 115                     "sqrtf32" => f.sqrt(),
 116                     "expf32" => f.exp(),
 117                     "exp2f32" => f.exp2(),
 118                     "logf32" => f.ln(),
 119                     "log10f32" => f.log10(),
 120                     "log2f32" => f.log2(),
 121                     "floorf32" => f.floor(),
 122                     "ceilf32" => f.ceil(),
 123                     "truncf32" => f.trunc(),
 124                     "roundf32" => f.round(),
 125                     _ => bug!(),
 126                 };
 127                 this.write_scalar(Scalar::from_u32(f.to_bits()), dest)?;
 128             }
 129
 130             #[rustfmt::skip]
 131             | "sinf64"
 132             | "fabsf64"
 133             | "cosf64"
 134             | "sqrtf64"
 135             | "expf64"
 136             | "exp2f64"
 137             | "logf64"
 138             | "log10f64"
 139             | "log2f64"
 140             | "floorf64"
 141             | "ceilf64"
 142             | "truncf64"
 143             | "roundf64"
 144             => {
 145                 let &[ref f] = check_arg_count(args)?;
 146                 // FIXME: Using host floats.
 147                 let f = f64::from_bits(this.read_scalar(f)?.to_u64()?);
 148                 let f = match intrinsic_name {
 149                     "sinf64" => f.sin(),
 150                     "fabsf64" => f.abs(),
 151                     "cosf64" => f.cos(),
 152                     "sqrtf64" => f.sqrt(),
 153                     "expf64" => f.exp(),
 154                     "exp2f64" => f.exp2(),
 155                     "logf64" => f.ln(),
 156                     "log10f64" => f.log10(),
 157                     "log2f64" => f.log2(),
 158                     "floorf64" => f.floor(),
 159                     "ceilf64" => f.ceil(),
 160                     "truncf64" => f.trunc(),
 161                     "roundf64" => f.round(),
 162                     _ => bug!(),
 163                 };
 164                 this.write_scalar(Scalar::from_u64(f.to_bits()), dest)?;
 165             }
 166
 167             #[rustfmt::skip]
 168             | "fadd_fast"
 169             | "fsub_fast"
 170             | "fmul_fast"
 171             | "fdiv_fast"
 172             | "frem_fast"
 173             => {
 174                 let &[ref a, ref b] = check_arg_count(args)?;
 175                 let a = this.read_immediate(a)?;
 176                 let b = this.read_immediate(b)?;
 177                 let op = match intrinsic_name {
 178                     "fadd_fast" => mir::BinOp::Add,
 179                     "fsub_fast" => mir::BinOp::Sub,
 180                     "fmul_fast" => mir::BinOp::Mul,
 181                     "fdiv_fast" => mir::BinOp::Div,
 182                     "frem_fast" => mir::BinOp::Rem,
 183                     _ => bug!(),
 184                 };
 185                 let float_finite = |x: ImmTy<'tcx, _>| -> InterpResult<'tcx, bool> {
 186                     Ok(match x.layout.ty.kind() {
 187                         ty::Float(FloatTy::F32) => x.to_scalar()?.to_f32()?.is_finite(),
 188                         ty::Float(FloatTy::F64) => x.to_scalar()?.to_f64()?.is_finite(),
 189                         _ => bug!(
 190                             "`{}` called with non-float input type {:?}",
 191                             intrinsic_name,
 192                             x.layout.ty
 193                         ),
 194                     })
 195                 };
 196                 match (float_finite(a)?, float_finite(b)?) {
 197                     (false, false) => throw_ub_format!(
 198                         "`{}` intrinsic called with non-finite value as both parameters",
 199                         intrinsic_name,
 200                     ),
 201                     (false, _) => throw_ub_format!(
 202                         "`{}` intrinsic called with non-finite value as first parameter",
 203                         intrinsic_name,
 204                     ),
 205                     (_, false) => throw_ub_format!(
 206                         "`{}` intrinsic called with non-finite value as second parameter",
 207                         intrinsic_name,
 208                     ),
 209                     _ => {}
 210                 }
 211                 this.binop_ignore_overflow(op, &a, &b, dest)?;
 212             }
 213
 214             #[rustfmt::skip]
 215             | "minnumf32"
 216             | "maxnumf32"
 217             | "copysignf32"
 218             => {
 219                 let &[ref a, ref b] = check_arg_count(args)?;
 220                 let a = this.read_scalar(a)?.to_f32()?;
 221                 let b = this.read_scalar(b)?.to_f32()?;
 222                 let res = match intrinsic_name {
 223                     "minnumf32" => a.min(b),
 224                     "maxnumf32" => a.max(b),
 225                     "copysignf32" => a.copy_sign(b),
 226                     _ => bug!(),
 227                 };
 228                 this.write_scalar(Scalar::from_f32(res), dest)?;
 229             }
 230
 231             #[rustfmt::skip]
 232             | "minnumf64"
 233             | "maxnumf64"
 234             | "copysignf64"
 235             => {
 236                 let &[ref a, ref b] = check_arg_count(args)?;
 237                 let a = this.read_scalar(a)?.to_f64()?;
 238                 let b = this.read_scalar(b)?.to_f64()?;
 239                 let res = match intrinsic_name {
 240                     "minnumf64" => a.min(b),
 241                     "maxnumf64" => a.max(b),
 242                     "copysignf64" => a.copy_sign(b),
 243                     _ => bug!(),
 244                 };
 245                 this.write_scalar(Scalar::from_f64(res), dest)?;
 246             }
 247
 248             "powf32" => {
 249                 let &[ref f, ref f2] = check_arg_count(args)?;
 250                 // FIXME: Using host floats.
 251                 let f = f32::from_bits(this.read_scalar(f)?.to_u32()?);
 252                 let f2 = f32::from_bits(this.read_scalar(f2)?.to_u32()?);
 253                 this.write_scalar(Scalar::from_u32(f.powf(f2).to_bits()), dest)?;
 254             }
 255
 256             "powf64" => {
 257                 let &[ref f, ref f2] = check_arg_count(args)?;
 258                 // FIXME: Using host floats.
 259                 let f = f64::from_bits(this.read_scalar(f)?.to_u64()?);
 260                 let f2 = f64::from_bits(this.read_scalar(f2)?.to_u64()?);
 261                 this.write_scalar(Scalar::from_u64(f.powf(f2).to_bits()), dest)?;
 262             }
 263
 264             "fmaf32" => {
 265                 let &[ref a, ref b, ref c] = check_arg_count(args)?;
 266                 let a = this.read_scalar(a)?.to_f32()?;
 267                 let b = this.read_scalar(b)?.to_f32()?;
 268                 let c = this.read_scalar(c)?.to_f32()?;
 269                 let res = a.mul_add(b, c).value;
 270                 this.write_scalar(Scalar::from_f32(res), dest)?;
 271             }
 272
 273             "fmaf64" => {
 274                 let &[ref a, ref b, ref c] = check_arg_count(args)?;
 275                 let a = this.read_scalar(a)?.to_f64()?;
 276                 let b = this.read_scalar(b)?.to_f64()?;
 277                 let c = this.read_scalar(c)?.to_f64()?;
 278                 let res = a.mul_add(b, c).value;
 279                 this.write_scalar(Scalar::from_f64(res), dest)?;
 280             }
 281
 282             "powif32" => {
 283                 let &[ref f, ref i] = check_arg_count(args)?;
 284                 // FIXME: Using host floats.
 285                 let f = f32::from_bits(this.read_scalar(f)?.to_u32()?);
 286                 let i = this.read_scalar(i)?.to_i32()?;
 287                 this.write_scalar(Scalar::from_u32(f.powi(i).to_bits()), dest)?;
 288             }
 289
 290             "powif64" => {
 291                 let &[ref f, ref i] = check_arg_count(args)?;
 292                 // FIXME: Using host floats.
 293                 let f = f64::from_bits(this.read_scalar(f)?.to_u64()?);
 294                 let i = this.read_scalar(i)?.to_i32()?;
 295                 this.write_scalar(Scalar::from_u64(f.powi(i).to_bits()), dest)?;
 296             }
 297
 298             "float_to_int_unchecked" => {
 299                 let &[ref val] = check_arg_count(args)?;
 300                 let val = this.read_immediate(val)?;
 301
 302                 let res = match val.layout.ty.kind() {
 303                     ty::Float(FloatTy::F32) =>
 304                         this.float_to_int_unchecked(val.to_scalar()?.to_f32()?, dest.layout.ty)?,
 305                     ty::Float(FloatTy::F64) =>
 306                         this.float_to_int_unchecked(val.to_scalar()?.to_f64()?, dest.layout.ty)?,
 307                     _ =>
 308                         bug!(
 309                             "`float_to_int_unchecked` called with non-float input type {:?}",
 310                             val.layout.ty
 311                         ),
 312                 };
 313
 314                 this.write_scalar(res, dest)?;
 315             }
 316
 317             // SIMD operations
 318             #[rustfmt::skip]
 319             | "simd_neg"
 320             | "simd_fabs" => {
 321                 let &[ref op] = check_arg_count(args)?;
 322                 let (op, op_len) = this.operand_to_simd(op)?;
 323                 let (dest, dest_len) = this.place_to_simd(dest)?;
 324
 325                 assert_eq!(dest_len, op_len);
 326
 327                 for i in 0..dest_len {
 328                     let op = this.read_immediate(&this.mplace_index(&op, i)?.into())?;
 329                     let dest = this.mplace_index(&dest, i)?;
 330                     let val = match intrinsic_name {
 331                         "simd_neg" => this.unary_op(mir::UnOp::Neg, &op)?.to_scalar()?,
 332                         "simd_fabs" => {
 333                             // Works for f32 and f64.
 334                             let ty::Float(float_ty) = op.layout.ty.kind() else {
 335                                 bug!("simd_fabs operand is not a float")
 336                             };
 337                             let op = op.to_scalar()?;
 338                             // FIXME: Using host floats.
 339                             match float_ty {
 340                                 FloatTy::F32 => Scalar::from_f32(op.to_f32()?.abs()),
 341                                 FloatTy::F64 => Scalar::from_f64(op.to_f64()?.abs()),
 342                             }
 343                         }
 344                         _ => bug!(),
 345                     };
 346                     this.write_scalar(val, &dest.into())?;
 347                 }
 348             }
 349             #[rustfmt::skip]
 350             | "simd_add"
 351             | "simd_sub"
 352             | "simd_mul"
 353             | "simd_div"
 354             | "simd_rem"
 355             | "simd_shl"
 356             | "simd_shr"
 357             | "simd_and"
 358             | "simd_or"
 359             | "simd_xor"
 360             | "simd_eq"
 361             | "simd_ne"
 362             | "simd_lt"
 363             | "simd_le"
 364             | "simd_gt"
 365             | "simd_ge" => {
 366                 use mir::BinOp;
 367
 368                 let &[ref left, ref right] = check_arg_count(args)?;
 369                 let (left, left_len) = this.operand_to_simd(left)?;
 370                 let (right, right_len) = this.operand_to_simd(right)?;
 371                 let (dest, dest_len) = this.place_to_simd(dest)?;
 372
 373                 assert_eq!(dest_len, left_len);
 374                 assert_eq!(dest_len, right_len);
 375
 376                 let op = match intrinsic_name {
 377                     "simd_add" => BinOp::Add,
 378                     "simd_sub" => BinOp::Sub,
 379                     "simd_mul" => BinOp::Mul,
 380                     "simd_div" => BinOp::Div,
 381                     "simd_rem" => BinOp::Rem,
 382                     "simd_shl" => BinOp::Shl,
 383                     "simd_shr" => BinOp::Shr,
 384                     "simd_and" => BinOp::BitAnd,
 385                     "simd_or" => BinOp::BitOr,
 386                     "simd_xor" => BinOp::BitXor,
 387                     "simd_eq" => BinOp::Eq,
 388                     "simd_ne" => BinOp::Ne,
 389                     "simd_lt" => BinOp::Lt,
 390                     "simd_le" => BinOp::Le,
 391                     "simd_gt" => BinOp::Gt,
 392                     "simd_ge" => BinOp::Ge,
 393                     _ => unreachable!(),
 394                 };
 395
 396                 for i in 0..dest_len {
 397                     let left = this.read_immediate(&this.mplace_index(&left, i)?.into())?;
 398                     let right = this.read_immediate(&this.mplace_index(&right, i)?.into())?;
 399                     let dest = this.mplace_index(&dest, i)?;
 400                     let (val, overflowed, ty) = this.overflowing_binary_op(op, &left, &right)?;
 401                     if matches!(op, BinOp::Shl | BinOp::Shr) {
 402                         // Shifts have extra UB as SIMD operations that the MIR binop does not have.
 403                         // See <https://github.com/rust-lang/rust/issues/91237>.
 404                         if overflowed {
 405                             let r_val = right.to_scalar()?.to_bits(right.layout.size)?;
 406                             throw_ub_format!("overflowing shift by {} in `{}` in SIMD lane {}", r_val, intrinsic_name, i);
 407                         }
 408                     }
 409                     if matches!(op, BinOp::Eq | BinOp::Ne | BinOp::Lt | BinOp::Le | BinOp::Gt | BinOp::Ge) {
 410                         // Special handling for boolean-returning operations
 411                         assert_eq!(ty, this.tcx.types.bool);
 412                         let val = val.to_bool().unwrap();
 413                         let val = bool_to_simd_element(val, dest.layout.size);
 414                         this.write_scalar(val, &dest.into())?;
 415                     } else {
 416                         assert_ne!(ty, this.tcx.types.bool);
 417                         assert_eq!(ty, dest.layout.ty);
 418                         this.write_scalar(val, &dest.into())?;
 419                     }
 420                 }
 421             }
 422             "simd_reduce_any" | "simd_reduce_all" => {
 423                 let &[ref op] = check_arg_count(args)?;
 424                 let (op, op_len) = this.operand_to_simd(op)?;
 425
 426                 // the neutral element
 427                 let mut res = match intrinsic_name {
 428                     "simd_reduce_any" => false,
 429                     "simd_reduce_all" => true,
 430                     _ => bug!(),
 431                 };
 432
 433                 for i in 0..op_len {
 434                     let op = this.read_immediate(&this.mplace_index(&op, i)?.into())?;
 435                     let val = simd_element_to_bool(op)?;
 436                     res = match intrinsic_name {
 437                         "simd_reduce_any" => res | val,
 438                         "simd_reduce_all" => res & val,
 439                         _ => bug!(),
 440                     };
 441                 }
 442
 443                 this.write_scalar(Scalar::from_bool(res), dest)?;
 444             }
 445             "simd_select" => {
 446                 let &[ref mask, ref yes, ref no] = check_arg_count(args)?;
 447                 let (mask, mask_len) = this.operand_to_simd(mask)?;
 448                 let (yes, yes_len) = this.operand_to_simd(yes)?;
 449                 let (no, no_len) = this.operand_to_simd(no)?;
 450                 let (dest, dest_len) = this.place_to_simd(dest)?;
 451
 452                 assert_eq!(dest_len, mask_len);
 453                 assert_eq!(dest_len, yes_len);
 454                 assert_eq!(dest_len, no_len);
 455
 456                 for i in 0..dest_len {
 457                     let mask = this.read_immediate(&this.mplace_index(&mask, i)?.into())?;
 458                     let yes = this.read_immediate(&this.mplace_index(&yes, i)?.into())?;
 459                     let no = this.read_immediate(&this.mplace_index(&no, i)?.into())?;
 460                     let dest = this.mplace_index(&dest, i)?;
 461
 462                     let mask = simd_element_to_bool(mask)?;
 463                     let val = if mask { yes } else { no };
 464                     this.write_immediate(*val, &dest.into())?;
 465                 }
 466             }
 467
 468             // Atomic operations
 469             "atomic_load" => this.atomic_load(args, dest, AtomicReadOp::SeqCst)?,
 470             "atomic_load_relaxed" => this.atomic_load(args, dest, AtomicReadOp::Relaxed)?,
 471             "atomic_load_acq" => this.atomic_load(args, dest, AtomicReadOp::Acquire)?,
 472
 473             "atomic_store" => this.atomic_store(args, AtomicWriteOp::SeqCst)?,
 474             "atomic_store_relaxed" => this.atomic_store(args, AtomicWriteOp::Relaxed)?,
 475             "atomic_store_rel" => this.atomic_store(args, AtomicWriteOp::Release)?,
 476
 477             "atomic_fence_acq" => this.atomic_fence(args, AtomicFenceOp::Acquire)?,
 478             "atomic_fence_rel" => this.atomic_fence(args, AtomicFenceOp::Release)?,
 479             "atomic_fence_acqrel" => this.atomic_fence(args, AtomicFenceOp::AcqRel)?,
 480             "atomic_fence" => this.atomic_fence(args, AtomicFenceOp::SeqCst)?,
 481
 482             "atomic_singlethreadfence_acq" => this.compiler_fence(args, AtomicFenceOp::Acquire)?,
 483             "atomic_singlethreadfence_rel" => this.compiler_fence(args, AtomicFenceOp::Release)?,
 484             "atomic_singlethreadfence_acqrel" =>
 485                 this.compiler_fence(args, AtomicFenceOp::AcqRel)?,
 486             "atomic_singlethreadfence" => this.compiler_fence(args, AtomicFenceOp::SeqCst)?,
 487
 488             "atomic_xchg" => this.atomic_exchange(args, dest, AtomicRwOp::SeqCst)?,
 489             "atomic_xchg_acq" => this.atomic_exchange(args, dest, AtomicRwOp::Acquire)?,
 490             "atomic_xchg_rel" => this.atomic_exchange(args, dest, AtomicRwOp::Release)?,
 491             "atomic_xchg_acqrel" => this.atomic_exchange(args, dest, AtomicRwOp::AcqRel)?,
 492             "atomic_xchg_relaxed" => this.atomic_exchange(args, dest, AtomicRwOp::Relaxed)?,
 493
 494             #[rustfmt::skip]
 495             "atomic_cxchg" =>
 496                 this.atomic_compare_exchange(args, dest, AtomicRwOp::SeqCst, AtomicReadOp::SeqCst)?,
 497             #[rustfmt::skip]
 498             "atomic_cxchg_acq" =>
 499                 this.atomic_compare_exchange(args, dest, AtomicRwOp::Acquire, AtomicReadOp::Acquire)?,
 500             #[rustfmt::skip]
 501             "atomic_cxchg_rel" =>
 502                 this.atomic_compare_exchange(args, dest, AtomicRwOp::Release, AtomicReadOp::Relaxed)?,
 503             #[rustfmt::skip]
 504             "atomic_cxchg_acqrel" =>
 505                 this.atomic_compare_exchange(args, dest, AtomicRwOp::AcqRel, AtomicReadOp::Acquire)?,
 506             #[rustfmt::skip]
 507             "atomic_cxchg_relaxed" =>
 508                 this.atomic_compare_exchange(args, dest, AtomicRwOp::Relaxed, AtomicReadOp::Relaxed)?,
 509             #[rustfmt::skip]
 510             "atomic_cxchg_acq_failrelaxed" =>
 511                 this.atomic_compare_exchange(args, dest, AtomicRwOp::Acquire, AtomicReadOp::Relaxed)?,
 512             #[rustfmt::skip]
 513             "atomic_cxchg_acqrel_failrelaxed" =>
 514                 this.atomic_compare_exchange(args, dest, AtomicRwOp::AcqRel, AtomicReadOp::Relaxed)?,
 515             #[rustfmt::skip]
 516             "atomic_cxchg_failrelaxed" =>
 517                 this.atomic_compare_exchange(args, dest, AtomicRwOp::SeqCst, AtomicReadOp::Relaxed)?,
 518             #[rustfmt::skip]
 519             "atomic_cxchg_failacq" =>
 520                 this.atomic_compare_exchange(args, dest, AtomicRwOp::SeqCst, AtomicReadOp::Acquire)?,
 521
 522             #[rustfmt::skip]
 523             "atomic_cxchgweak" =>
 524                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::SeqCst, AtomicReadOp::SeqCst)?,
 525             #[rustfmt::skip]
 526             "atomic_cxchgweak_acq" =>
 527                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::Acquire, AtomicReadOp::Acquire)?,
 528             #[rustfmt::skip]
 529             "atomic_cxchgweak_rel" =>
 530                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::Release, AtomicReadOp::Relaxed)?,
 531             #[rustfmt::skip]
 532             "atomic_cxchgweak_acqrel" =>
 533                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::AcqRel, AtomicReadOp::Acquire)?,
 534             #[rustfmt::skip]
 535             "atomic_cxchgweak_relaxed" =>
 536                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::Relaxed, AtomicReadOp::Relaxed)?,
 537             #[rustfmt::skip]
 538             "atomic_cxchgweak_acq_failrelaxed" =>
 539                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::Acquire, AtomicReadOp::Relaxed)?,
 540             #[rustfmt::skip]
 541             "atomic_cxchgweak_acqrel_failrelaxed" =>
 542                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::AcqRel, AtomicReadOp::Relaxed)?,
 543             #[rustfmt::skip]
 544             "atomic_cxchgweak_failrelaxed" =>
 545                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::SeqCst, AtomicReadOp::Relaxed)?,
 546             #[rustfmt::skip]
 547             "atomic_cxchgweak_failacq" =>
 548                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::SeqCst, AtomicReadOp::Acquire)?,
 549
 550             #[rustfmt::skip]
 551             "atomic_or" =>
 552                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitOr, false), AtomicRwOp::SeqCst)?,
 553             #[rustfmt::skip]
 554             "atomic_or_acq" =>
 555                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitOr, false), AtomicRwOp::Acquire)?,
 556             #[rustfmt::skip]
 557             "atomic_or_rel" =>
 558                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitOr, false), AtomicRwOp::Release)?,
 559             #[rustfmt::skip]
 560             "atomic_or_acqrel" =>
 561                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitOr, false), AtomicRwOp::AcqRel)?,
 562             #[rustfmt::skip]
 563             "atomic_or_relaxed" =>
 564                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitOr, false), AtomicRwOp::Relaxed)?,
 565             #[rustfmt::skip]
 566             "atomic_xor" =>
 567                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitXor, false), AtomicRwOp::SeqCst)?,
 568             #[rustfmt::skip]
 569             "atomic_xor_acq" =>
 570                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitXor, false), AtomicRwOp::Acquire)?,
 571             #[rustfmt::skip]
 572             "atomic_xor_rel" =>
 573                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitXor, false), AtomicRwOp::Release)?,
 574             #[rustfmt::skip]
 575             "atomic_xor_acqrel" =>
 576                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitXor, false), AtomicRwOp::AcqRel)?,
 577             #[rustfmt::skip]
 578             "atomic_xor_relaxed" =>
 579                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitXor, false), AtomicRwOp::Relaxed)?,
 580             #[rustfmt::skip]
 581             "atomic_and" =>
 582                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, false), AtomicRwOp::SeqCst)?,
 583             #[rustfmt::skip]
 584             "atomic_and_acq" =>
 585                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, false), AtomicRwOp::Acquire)?,
 586             #[rustfmt::skip]
 587             "atomic_and_rel" =>
 588                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, false), AtomicRwOp::Release)?,
 589             #[rustfmt::skip]
 590             "atomic_and_acqrel" =>
 591                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, false), AtomicRwOp::AcqRel)?,
 592             #[rustfmt::skip]
 593             "atomic_and_relaxed" =>
 594                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, false), AtomicRwOp::Relaxed)?,
 595             #[rustfmt::skip]
 596             "atomic_nand" =>
 597                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, true), AtomicRwOp::SeqCst)?,
 598             #[rustfmt::skip]
 599             "atomic_nand_acq" =>
 600                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, true), AtomicRwOp::Acquire)?,
 601             #[rustfmt::skip]
 602             "atomic_nand_rel" =>
 603                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, true), AtomicRwOp::Release)?,
 604             #[rustfmt::skip]
 605             "atomic_nand_acqrel" =>
 606                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, true), AtomicRwOp::AcqRel)?,
 607             #[rustfmt::skip]
 608             "atomic_nand_relaxed" =>
 609                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, true), AtomicRwOp::Relaxed)?,
 610             #[rustfmt::skip]
 611             "atomic_xadd" =>
 612                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Add, false), AtomicRwOp::SeqCst)?,
 613             #[rustfmt::skip]
 614             "atomic_xadd_acq" =>
 615                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Add, false), AtomicRwOp::Acquire)?,
 616             #[rustfmt::skip]
 617             "atomic_xadd_rel" =>
 618                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Add, false), AtomicRwOp::Release)?,
 619             #[rustfmt::skip]
 620             "atomic_xadd_acqrel" =>
 621                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Add, false), AtomicRwOp::AcqRel)?,
 622             #[rustfmt::skip]
 623             "atomic_xadd_relaxed" =>
 624                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Add, false), AtomicRwOp::Relaxed)?,
 625             #[rustfmt::skip]
 626             "atomic_xsub" =>
 627                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Sub, false), AtomicRwOp::SeqCst)?,
 628             #[rustfmt::skip]
 629             "atomic_xsub_acq" =>
 630                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Sub, false), AtomicRwOp::Acquire)?,
 631             #[rustfmt::skip]
 632             "atomic_xsub_rel" =>
 633                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Sub, false), AtomicRwOp::Release)?,
 634             #[rustfmt::skip]
 635             "atomic_xsub_acqrel" =>
 636                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Sub, false), AtomicRwOp::AcqRel)?,
 637             #[rustfmt::skip]
 638             "atomic_xsub_relaxed" =>
 639                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Sub, false), AtomicRwOp::Relaxed)?,
 640             "atomic_min" => this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::SeqCst)?,
 641             "atomic_min_acq" => this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::Acquire)?,
 642             "atomic_min_rel" => this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::Release)?,
 643             "atomic_min_acqrel" => this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::AcqRel)?,
 644             "atomic_min_relaxed" =>
 645                 this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::Relaxed)?,
 646             "atomic_max" => this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::SeqCst)?,
 647             "atomic_max_acq" => this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::Acquire)?,
 648             "atomic_max_rel" => this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::Release)?,
 649             "atomic_max_acqrel" => this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::AcqRel)?,
 650             "atomic_max_relaxed" =>
 651                 this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::Relaxed)?,
 652             "atomic_umin" => this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::SeqCst)?,
 653             "atomic_umin_acq" => this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::Acquire)?,
 654             "atomic_umin_rel" => this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::Release)?,
 655             "atomic_umin_acqrel" =>
 656                 this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::AcqRel)?,
 657             "atomic_umin_relaxed" =>
 658                 this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::Relaxed)?,
 659             "atomic_umax" => this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::SeqCst)?,
 660             "atomic_umax_acq" => this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::Acquire)?,
 661             "atomic_umax_rel" => this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::Release)?,
 662             "atomic_umax_acqrel" =>
 663                 this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::AcqRel)?,
 664             "atomic_umax_relaxed" =>
 665                 this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::Relaxed)?,
 666
 667             // Other
 668             "exact_div" => {
 669                 let &[ref num, ref denom] = check_arg_count(args)?;
 670                 this.exact_div(&this.read_immediate(num)?, &this.read_immediate(denom)?, dest)?;
 671             }
 672
 673             "try" => return this.handle_try(args, dest, ret),
 674
 675             "breakpoint" => {
 676                 let &[] = check_arg_count(args)?;
 677                 // normally this would raise a SIGTRAP, which aborts if no debugger is connected
 678                 throw_machine_stop!(TerminationInfo::Abort("Trace/breakpoint trap".to_string()))
 679             }
 680
 681             name => throw_unsup_format!("unimplemented intrinsic: {}", name),
 682         }
 683
 684         trace!("{:?}", this.dump_place(**dest));
 685         this.go_to_block(ret);
 686         Ok(())
 687     }
 688
 689     fn atomic_load(
 690         &mut self,
 691         args: &[OpTy<'tcx, Tag>],
 692         dest: &PlaceTy<'tcx, Tag>,
 693         atomic: AtomicReadOp,
 694     ) -> InterpResult<'tcx> {
 695         let this = self.eval_context_mut();
 696
 697         let &[ref place] = check_arg_count(args)?;
 698         let place = this.deref_operand(place)?;
 699
 700         // make sure it fits into a scalar; otherwise it cannot be atomic
 701         let val = this.read_scalar_atomic(&place, atomic)?;
 702
 703         // Check alignment requirements. Atomics must always be aligned to their size,
 704         // even if the type they wrap would be less aligned (e.g. AtomicU64 on 32bit must
 705         // be 8-aligned).
 706         let align = Align::from_bytes(place.layout.size.bytes()).unwrap();
 707         this.memory.check_ptr_access_align(
 708             place.ptr,
 709             place.layout.size,
 710             align,
 711             CheckInAllocMsg::MemoryAccessTest,
 712         )?;
 713         // Perform regular access.
 714         this.write_scalar(val, dest)?;
 715         Ok(())
 716     }
 717
 718     fn atomic_store(
 719         &mut self,
 720         args: &[OpTy<'tcx, Tag>],
 721         atomic: AtomicWriteOp,
 722     ) -> InterpResult<'tcx> {
 723         let this = self.eval_context_mut();
 724
 725         let &[ref place, ref val] = check_arg_count(args)?;
 726         let place = this.deref_operand(place)?;
 727         let val = this.read_scalar(val)?; // make sure it fits into a scalar; otherwise it cannot be atomic
 728
 729         // Check alignment requirements. Atomics must always be aligned to their size,
 730         // even if the type they wrap would be less aligned (e.g. AtomicU64 on 32bit must
 731         // be 8-aligned).
 732         let align = Align::from_bytes(place.layout.size.bytes()).unwrap();
 733         this.memory.check_ptr_access_align(
 734             place.ptr,
 735             place.layout.size,
 736             align,
 737             CheckInAllocMsg::MemoryAccessTest,
 738         )?;
 739
 740         // Perform atomic store
 741         this.write_scalar_atomic(val, &place, atomic)?;
 742         Ok(())
 743     }
 744
 745     fn compiler_fence(
 746         &mut self,
 747         args: &[OpTy<'tcx, Tag>],
 748         atomic: AtomicFenceOp,
 749     ) -> InterpResult<'tcx> {
 750         let &[] = check_arg_count(args)?;
 751         let _ = atomic;
 752         //FIXME: compiler fences are currently ignored
 753         Ok(())
 754     }
 755
 756     fn atomic_fence(
 757         &mut self,
 758         args: &[OpTy<'tcx, Tag>],
 759         atomic: AtomicFenceOp,
 760     ) -> InterpResult<'tcx> {
 761         let this = self.eval_context_mut();
 762         let &[] = check_arg_count(args)?;
 763         this.validate_atomic_fence(atomic)?;
 764         Ok(())
 765     }
 766
 767     fn atomic_op(
 768         &mut self,
 769         args: &[OpTy<'tcx, Tag>],
 770         dest: &PlaceTy<'tcx, Tag>,
 771         atomic_op: AtomicOp,
 772         atomic: AtomicRwOp,
 773     ) -> InterpResult<'tcx> {
 774         let this = self.eval_context_mut();
 775
 776         let &[ref place, ref rhs] = check_arg_count(args)?;
 777         let place = this.deref_operand(place)?;
 778
 779         if !place.layout.ty.is_integral() {
 780             bug!("Atomic arithmetic operations only work on integer types");
 781         }
 782         let rhs = this.read_immediate(rhs)?;
 783
 784         // Check alignment requirements. Atomics must always be aligned to their size,
 785         // even if the type they wrap would be less aligned (e.g. AtomicU64 on 32bit must
 786         // be 8-aligned).
 787         let align = Align::from_bytes(place.layout.size.bytes()).unwrap();
 788         this.memory.check_ptr_access_align(
 789             place.ptr,
 790             place.layout.size,
 791             align,
 792             CheckInAllocMsg::MemoryAccessTest,
 793         )?;
 794
 795         match atomic_op {
 796             AtomicOp::Min => {
 797                 let old = this.atomic_min_max_scalar(&place, rhs, true, atomic)?;
 798                 this.write_immediate(*old, &dest)?; // old value is returned
 799                 Ok(())
 800             }
 801             AtomicOp::Max => {
 802                 let old = this.atomic_min_max_scalar(&place, rhs, false, atomic)?;
 803                 this.write_immediate(*old, &dest)?; // old value is returned
 804                 Ok(())
 805             }
 806             AtomicOp::MirOp(op, neg) => {
 807                 let old = this.atomic_op_immediate(&place, &rhs, op, neg, atomic)?;
 808                 this.write_immediate(*old, dest)?; // old value is returned
 809                 Ok(())
 810             }
 811         }
 812     }
 813
 814     fn atomic_exchange(
 815         &mut self,
 816         args: &[OpTy<'tcx, Tag>],
 817         dest: &PlaceTy<'tcx, Tag>,
 818         atomic: AtomicRwOp,
 819     ) -> InterpResult<'tcx> {
 820         let this = self.eval_context_mut();
 821
 822         let &[ref place, ref new] = check_arg_count(args)?;
 823         let place = this.deref_operand(place)?;
 824         let new = this.read_scalar(new)?;
 825
 826         // Check alignment requirements. Atomics must always be aligned to their size,
 827         // even if the type they wrap would be less aligned (e.g. AtomicU64 on 32bit must
 828         // be 8-aligned).
 829         let align = Align::from_bytes(place.layout.size.bytes()).unwrap();
 830         this.memory.check_ptr_access_align(
 831             place.ptr,
 832             place.layout.size,
 833             align,
 834             CheckInAllocMsg::MemoryAccessTest,
 835         )?;
 836
 837         let old = this.atomic_exchange_scalar(&place, new, atomic)?;
 838         this.write_scalar(old, dest)?; // old value is returned
 839         Ok(())
 840     }
 841
 842     fn atomic_compare_exchange_impl(
 843         &mut self,
 844         args: &[OpTy<'tcx, Tag>],
 845         dest: &PlaceTy<'tcx, Tag>,
 846         success: AtomicRwOp,
 847         fail: AtomicReadOp,
 848         can_fail_spuriously: bool,
 849     ) -> InterpResult<'tcx> {
 850         let this = self.eval_context_mut();
 851
 852         let &[ref place, ref expect_old, ref new] = check_arg_count(args)?;
 853         let place = this.deref_operand(place)?;
 854         let expect_old = this.read_immediate(expect_old)?; // read as immediate for the sake of `binary_op()`
 855         let new = this.read_scalar(new)?;
 856
 857         // Check alignment requirements. Atomics must always be aligned to their size,
 858         // even if the type they wrap would be less aligned (e.g. AtomicU64 on 32bit must
 859         // be 8-aligned).
 860         let align = Align::from_bytes(place.layout.size.bytes()).unwrap();
 861         this.memory.check_ptr_access_align(
 862             place.ptr,
 863             place.layout.size,
 864             align,
 865             CheckInAllocMsg::MemoryAccessTest,
 866         )?;
 867
 868         let old = this.atomic_compare_exchange_scalar(
 869             &place,
 870             &expect_old,
 871             new,
 872             success,
 873             fail,
 874             can_fail_spuriously,
 875         )?;
 876
 877         // Return old value.
 878         this.write_immediate(old, dest)?;
 879         Ok(())
 880     }
 881
 882     fn atomic_compare_exchange(
 883         &mut self,
 884         args: &[OpTy<'tcx, Tag>],
 885         dest: &PlaceTy<'tcx, Tag>,
 886         success: AtomicRwOp,
 887         fail: AtomicReadOp,
 888     ) -> InterpResult<'tcx> {
 889         self.atomic_compare_exchange_impl(args, dest, success, fail, false)
 890     }
 891
 892     fn atomic_compare_exchange_weak(
 893         &mut self,
 894         args: &[OpTy<'tcx, Tag>],
 895         dest: &PlaceTy<'tcx, Tag>,
 896         success: AtomicRwOp,
 897         fail: AtomicReadOp,
 898     ) -> InterpResult<'tcx> {
 899         self.atomic_compare_exchange_impl(args, dest, success, fail, true)
 900     }
 901
 902     fn float_to_int_unchecked<F>(
 903         &self,
 904         f: F,
 905         dest_ty: ty::Ty<'tcx>,
 906     ) -> InterpResult<'tcx, Scalar<Tag>>
 907     where
 908         F: Float + Into<Scalar<Tag>>,
 909     {
 910         let this = self.eval_context_ref();
 911
 912         // Step 1: cut off the fractional part of `f`. The result of this is
 913         // guaranteed to be precisely representable in IEEE floats.
 914         let f = f.round_to_integral(Round::TowardZero).value;
 915
 916         // Step 2: Cast the truncated float to the target integer type and see if we lose any information in this step.
 917         Ok(match dest_ty.kind() {
 918             // Unsigned
 919             ty::Uint(t) => {
 920                 let size = Integer::from_uint_ty(this, *t).size();
 921                 let res = f.to_u128(size.bits_usize());
 922                 if res.status.is_empty() {
 923                     // No status flags means there was no further rounding or other loss of precision.
 924                     Scalar::from_uint(res.value, size)
 925                 } else {
 926                     // `f` was not representable in this integer type.
 927                     throw_ub_format!(
 928                         "`float_to_int_unchecked` intrinsic called on {} which cannot be represented in target type `{:?}`",
 929                         f,
 930                         dest_ty,
 931                     );
 932                 }
 933             }
 934             // Signed
 935             ty::Int(t) => {
 936                 let size = Integer::from_int_ty(this, *t).size();
 937                 let res = f.to_i128(size.bits_usize());
 938                 if res.status.is_empty() {
 939                     // No status flags means there was no further rounding or other loss of precision.
 940                     Scalar::from_int(res.value, size)
 941                 } else {
 942                     // `f` was not representable in this integer type.
 943                     throw_ub_format!(
 944                         "`float_to_int_unchecked` intrinsic called on {} which cannot be represented in target type `{:?}`",
 945                         f,
 946                         dest_ty,
 947                     );
 948                 }
 949             }
 950             // Nothing else
 951             _ => bug!("`float_to_int_unchecked` called with non-int output type {:?}", dest_ty),
 952         })
 953     }
 954 }