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_add"
 320             | "simd_sub"
 321             | "simd_mul"
 322             | "simd_div"
 323             | "simd_rem"
 324             | "simd_shl"
 325             | "simd_shr"
 326             | "simd_and"
 327             | "simd_or"
 328             | "simd_eq" => {
 329                 let &[ref left, ref right] = check_arg_count(args)?;
 330                 let (left, left_len) = this.operand_to_simd(left)?;
 331                 let (right, right_len) = this.operand_to_simd(right)?;
 332                 let (dest, dest_len) = this.place_to_simd(dest)?;
 333
 334                 assert_eq!(dest_len, left_len);
 335                 assert_eq!(dest_len, right_len);
 336
 337                 let op = match intrinsic_name {
 338                     "simd_add" => mir::BinOp::Add,
 339                     "simd_sub" => mir::BinOp::Sub,
 340                     "simd_mul" => mir::BinOp::Mul,
 341                     "simd_div" => mir::BinOp::Div,
 342                     "simd_rem" => mir::BinOp::Rem,
 343                     "simd_shl" => mir::BinOp::Shl,
 344                     "simd_shr" => mir::BinOp::Shr,
 345                     "simd_and" => mir::BinOp::BitAnd,
 346                     "simd_or" => mir::BinOp::BitOr,
 347                     "simd_eq" => mir::BinOp::Eq,
 348                     _ => unreachable!(),
 349                 };
 350
 351                 for i in 0..dest_len {
 352                     let left = this.read_immediate(&this.mplace_index(&left, i)?.into())?;
 353                     let right = this.read_immediate(&this.mplace_index(&right, i)?.into())?;
 354                     let dest = this.mplace_index(&dest, i)?;
 355                     let (val, overflowed, ty) = this.overflowing_binary_op(op, &left, &right)?;
 356                     if matches!(op, mir::BinOp::Shl | mir::BinOp::Shr) {
 357                         // Shifts have extra UB as SIMD operations that the MIR binop does not have.
 358                         // See <https://github.com/rust-lang/rust/issues/91237>.
 359                         if overflowed {
 360                             let r_val = right.to_scalar()?.to_bits(right.layout.size)?;
 361                             throw_ub_format!("overflowing shift by {} in `{}` in SIMD lane {}", r_val, intrinsic_name, i);
 362                         }
 363                     }
 364                     if matches!(op, mir::BinOp::Eq) {
 365                         // Special handling for boolean-returning operations
 366                         assert_eq!(ty, this.tcx.types.bool);
 367                         let val = val.to_bool().unwrap();
 368                         let val = bool_to_simd_element(val, dest.layout.size);
 369                         this.write_scalar(val, &dest.into())?;
 370                     } else {
 371                         assert_eq!(ty, dest.layout.ty);
 372                         this.write_scalar(val, &dest.into())?;
 373                     }
 374                 }
 375             }
 376             "simd_reduce_any" => {
 377                 let &[ref arg] = check_arg_count(args)?;
 378                 let (arg, arg_len) = this.operand_to_simd(arg)?;
 379
 380                 let mut res = false; // the neutral element
 381                 for i in 0..arg_len {
 382                     let op = this.read_immediate(&this.mplace_index(&arg, i)?.into())?;
 383                     let val = simd_element_to_bool(op)?;
 384                     res = res | val;
 385                 }
 386
 387                 this.write_scalar(Scalar::from_bool(res), dest)?;
 388             }
 389             "simd_select" => {
 390                 let &[ref mask, ref yes, ref no] = check_arg_count(args)?;
 391                 let (mask, mask_len) = this.operand_to_simd(mask)?;
 392                 let (yes, yes_len) = this.operand_to_simd(yes)?;
 393                 let (no, no_len) = this.operand_to_simd(no)?;
 394                 let (dest, dest_len) = this.place_to_simd(dest)?;
 395
 396                 assert_eq!(dest_len, mask_len);
 397                 assert_eq!(dest_len, yes_len);
 398                 assert_eq!(dest_len, no_len);
 399
 400                 for i in 0..dest_len {
 401                     let mask = this.read_immediate(&this.mplace_index(&mask, i)?.into())?;
 402                     let yes = this.read_immediate(&this.mplace_index(&yes, i)?.into())?;
 403                     let no = this.read_immediate(&this.mplace_index(&no, i)?.into())?;
 404                     let dest = this.mplace_index(&dest, i)?;
 405
 406                     let mask = simd_element_to_bool(mask)?;
 407                     let val = if mask { yes } else { no };
 408                     this.write_immediate(*val, &dest.into())?;
 409                 }
 410             }
 411
 412             // Atomic operations
 413             "atomic_load" => this.atomic_load(args, dest, AtomicReadOp::SeqCst)?,
 414             "atomic_load_relaxed" => this.atomic_load(args, dest, AtomicReadOp::Relaxed)?,
 415             "atomic_load_acq" => this.atomic_load(args, dest, AtomicReadOp::Acquire)?,
 416
 417             "atomic_store" => this.atomic_store(args, AtomicWriteOp::SeqCst)?,
 418             "atomic_store_relaxed" => this.atomic_store(args, AtomicWriteOp::Relaxed)?,
 419             "atomic_store_rel" => this.atomic_store(args, AtomicWriteOp::Release)?,
 420
 421             "atomic_fence_acq" => this.atomic_fence(args, AtomicFenceOp::Acquire)?,
 422             "atomic_fence_rel" => this.atomic_fence(args, AtomicFenceOp::Release)?,
 423             "atomic_fence_acqrel" => this.atomic_fence(args, AtomicFenceOp::AcqRel)?,
 424             "atomic_fence" => this.atomic_fence(args, AtomicFenceOp::SeqCst)?,
 425
 426             "atomic_singlethreadfence_acq" => this.compiler_fence(args, AtomicFenceOp::Acquire)?,
 427             "atomic_singlethreadfence_rel" => this.compiler_fence(args, AtomicFenceOp::Release)?,
 428             "atomic_singlethreadfence_acqrel" =>
 429                 this.compiler_fence(args, AtomicFenceOp::AcqRel)?,
 430             "atomic_singlethreadfence" => this.compiler_fence(args, AtomicFenceOp::SeqCst)?,
 431
 432             "atomic_xchg" => this.atomic_exchange(args, dest, AtomicRwOp::SeqCst)?,
 433             "atomic_xchg_acq" => this.atomic_exchange(args, dest, AtomicRwOp::Acquire)?,
 434             "atomic_xchg_rel" => this.atomic_exchange(args, dest, AtomicRwOp::Release)?,
 435             "atomic_xchg_acqrel" => this.atomic_exchange(args, dest, AtomicRwOp::AcqRel)?,
 436             "atomic_xchg_relaxed" => this.atomic_exchange(args, dest, AtomicRwOp::Relaxed)?,
 437
 438             #[rustfmt::skip]
 439             "atomic_cxchg" =>
 440                 this.atomic_compare_exchange(args, dest, AtomicRwOp::SeqCst, AtomicReadOp::SeqCst)?,
 441             #[rustfmt::skip]
 442             "atomic_cxchg_acq" =>
 443                 this.atomic_compare_exchange(args, dest, AtomicRwOp::Acquire, AtomicReadOp::Acquire)?,
 444             #[rustfmt::skip]
 445             "atomic_cxchg_rel" =>
 446                 this.atomic_compare_exchange(args, dest, AtomicRwOp::Release, AtomicReadOp::Relaxed)?,
 447             #[rustfmt::skip]
 448             "atomic_cxchg_acqrel" =>
 449                 this.atomic_compare_exchange(args, dest, AtomicRwOp::AcqRel, AtomicReadOp::Acquire)?,
 450             #[rustfmt::skip]
 451             "atomic_cxchg_relaxed" =>
 452                 this.atomic_compare_exchange(args, dest, AtomicRwOp::Relaxed, AtomicReadOp::Relaxed)?,
 453             #[rustfmt::skip]
 454             "atomic_cxchg_acq_failrelaxed" =>
 455                 this.atomic_compare_exchange(args, dest, AtomicRwOp::Acquire, AtomicReadOp::Relaxed)?,
 456             #[rustfmt::skip]
 457             "atomic_cxchg_acqrel_failrelaxed" =>
 458                 this.atomic_compare_exchange(args, dest, AtomicRwOp::AcqRel, AtomicReadOp::Relaxed)?,
 459             #[rustfmt::skip]
 460             "atomic_cxchg_failrelaxed" =>
 461                 this.atomic_compare_exchange(args, dest, AtomicRwOp::SeqCst, AtomicReadOp::Relaxed)?,
 462             #[rustfmt::skip]
 463             "atomic_cxchg_failacq" =>
 464                 this.atomic_compare_exchange(args, dest, AtomicRwOp::SeqCst, AtomicReadOp::Acquire)?,
 465
 466             #[rustfmt::skip]
 467             "atomic_cxchgweak" =>
 468                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::SeqCst, AtomicReadOp::SeqCst)?,
 469             #[rustfmt::skip]
 470             "atomic_cxchgweak_acq" =>
 471                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::Acquire, AtomicReadOp::Acquire)?,
 472             #[rustfmt::skip]
 473             "atomic_cxchgweak_rel" =>
 474                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::Release, AtomicReadOp::Relaxed)?,
 475             #[rustfmt::skip]
 476             "atomic_cxchgweak_acqrel" =>
 477                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::AcqRel, AtomicReadOp::Acquire)?,
 478             #[rustfmt::skip]
 479             "atomic_cxchgweak_relaxed" =>
 480                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::Relaxed, AtomicReadOp::Relaxed)?,
 481             #[rustfmt::skip]
 482             "atomic_cxchgweak_acq_failrelaxed" =>
 483                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::Acquire, AtomicReadOp::Relaxed)?,
 484             #[rustfmt::skip]
 485             "atomic_cxchgweak_acqrel_failrelaxed" =>
 486                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::AcqRel, AtomicReadOp::Relaxed)?,
 487             #[rustfmt::skip]
 488             "atomic_cxchgweak_failrelaxed" =>
 489                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::SeqCst, AtomicReadOp::Relaxed)?,
 490             #[rustfmt::skip]
 491             "atomic_cxchgweak_failacq" =>
 492                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::SeqCst, AtomicReadOp::Acquire)?,
 493
 494             #[rustfmt::skip]
 495             "atomic_or" =>
 496                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitOr, false), AtomicRwOp::SeqCst)?,
 497             #[rustfmt::skip]
 498             "atomic_or_acq" =>
 499                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitOr, false), AtomicRwOp::Acquire)?,
 500             #[rustfmt::skip]
 501             "atomic_or_rel" =>
 502                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitOr, false), AtomicRwOp::Release)?,
 503             #[rustfmt::skip]
 504             "atomic_or_acqrel" =>
 505                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitOr, false), AtomicRwOp::AcqRel)?,
 506             #[rustfmt::skip]
 507             "atomic_or_relaxed" =>
 508                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitOr, false), AtomicRwOp::Relaxed)?,
 509             #[rustfmt::skip]
 510             "atomic_xor" =>
 511                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitXor, false), AtomicRwOp::SeqCst)?,
 512             #[rustfmt::skip]
 513             "atomic_xor_acq" =>
 514                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitXor, false), AtomicRwOp::Acquire)?,
 515             #[rustfmt::skip]
 516             "atomic_xor_rel" =>
 517                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitXor, false), AtomicRwOp::Release)?,
 518             #[rustfmt::skip]
 519             "atomic_xor_acqrel" =>
 520                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitXor, false), AtomicRwOp::AcqRel)?,
 521             #[rustfmt::skip]
 522             "atomic_xor_relaxed" =>
 523                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitXor, false), AtomicRwOp::Relaxed)?,
 524             #[rustfmt::skip]
 525             "atomic_and" =>
 526                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, false), AtomicRwOp::SeqCst)?,
 527             #[rustfmt::skip]
 528             "atomic_and_acq" =>
 529                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, false), AtomicRwOp::Acquire)?,
 530             #[rustfmt::skip]
 531             "atomic_and_rel" =>
 532                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, false), AtomicRwOp::Release)?,
 533             #[rustfmt::skip]
 534             "atomic_and_acqrel" =>
 535                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, false), AtomicRwOp::AcqRel)?,
 536             #[rustfmt::skip]
 537             "atomic_and_relaxed" =>
 538                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, false), AtomicRwOp::Relaxed)?,
 539             #[rustfmt::skip]
 540             "atomic_nand" =>
 541                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, true), AtomicRwOp::SeqCst)?,
 542             #[rustfmt::skip]
 543             "atomic_nand_acq" =>
 544                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, true), AtomicRwOp::Acquire)?,
 545             #[rustfmt::skip]
 546             "atomic_nand_rel" =>
 547                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, true), AtomicRwOp::Release)?,
 548             #[rustfmt::skip]
 549             "atomic_nand_acqrel" =>
 550                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, true), AtomicRwOp::AcqRel)?,
 551             #[rustfmt::skip]
 552             "atomic_nand_relaxed" =>
 553                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, true), AtomicRwOp::Relaxed)?,
 554             #[rustfmt::skip]
 555             "atomic_xadd" =>
 556                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Add, false), AtomicRwOp::SeqCst)?,
 557             #[rustfmt::skip]
 558             "atomic_xadd_acq" =>
 559                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Add, false), AtomicRwOp::Acquire)?,
 560             #[rustfmt::skip]
 561             "atomic_xadd_rel" =>
 562                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Add, false), AtomicRwOp::Release)?,
 563             #[rustfmt::skip]
 564             "atomic_xadd_acqrel" =>
 565                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Add, false), AtomicRwOp::AcqRel)?,
 566             #[rustfmt::skip]
 567             "atomic_xadd_relaxed" =>
 568                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Add, false), AtomicRwOp::Relaxed)?,
 569             #[rustfmt::skip]
 570             "atomic_xsub" =>
 571                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Sub, false), AtomicRwOp::SeqCst)?,
 572             #[rustfmt::skip]
 573             "atomic_xsub_acq" =>
 574                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Sub, false), AtomicRwOp::Acquire)?,
 575             #[rustfmt::skip]
 576             "atomic_xsub_rel" =>
 577                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Sub, false), AtomicRwOp::Release)?,
 578             #[rustfmt::skip]
 579             "atomic_xsub_acqrel" =>
 580                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Sub, false), AtomicRwOp::AcqRel)?,
 581             #[rustfmt::skip]
 582             "atomic_xsub_relaxed" =>
 583                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Sub, false), AtomicRwOp::Relaxed)?,
 584             "atomic_min" => this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::SeqCst)?,
 585             "atomic_min_acq" => this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::Acquire)?,
 586             "atomic_min_rel" => this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::Release)?,
 587             "atomic_min_acqrel" => this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::AcqRel)?,
 588             "atomic_min_relaxed" =>
 589                 this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::Relaxed)?,
 590             "atomic_max" => this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::SeqCst)?,
 591             "atomic_max_acq" => this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::Acquire)?,
 592             "atomic_max_rel" => this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::Release)?,
 593             "atomic_max_acqrel" => this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::AcqRel)?,
 594             "atomic_max_relaxed" =>
 595                 this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::Relaxed)?,
 596             "atomic_umin" => this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::SeqCst)?,
 597             "atomic_umin_acq" => this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::Acquire)?,
 598             "atomic_umin_rel" => this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::Release)?,
 599             "atomic_umin_acqrel" =>
 600                 this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::AcqRel)?,
 601             "atomic_umin_relaxed" =>
 602                 this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::Relaxed)?,
 603             "atomic_umax" => this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::SeqCst)?,
 604             "atomic_umax_acq" => this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::Acquire)?,
 605             "atomic_umax_rel" => this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::Release)?,
 606             "atomic_umax_acqrel" =>
 607                 this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::AcqRel)?,
 608             "atomic_umax_relaxed" =>
 609                 this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::Relaxed)?,
 610
 611             // Other
 612             "exact_div" => {
 613                 let &[ref num, ref denom] = check_arg_count(args)?;
 614                 this.exact_div(&this.read_immediate(num)?, &this.read_immediate(denom)?, dest)?;
 615             }
 616
 617             "try" => return this.handle_try(args, dest, ret),
 618
 619             "breakpoint" => {
 620                 let &[] = check_arg_count(args)?;
 621                 // normally this would raise a SIGTRAP, which aborts if no debugger is connected
 622                 throw_machine_stop!(TerminationInfo::Abort("Trace/breakpoint trap".to_string()))
 623             }
 624
 625             name => throw_unsup_format!("unimplemented intrinsic: {}", name),
 626         }
 627
 628         trace!("{:?}", this.dump_place(**dest));
 629         this.go_to_block(ret);
 630         Ok(())
 631     }
 632
 633     fn atomic_load(
 634         &mut self,
 635         args: &[OpTy<'tcx, Tag>],
 636         dest: &PlaceTy<'tcx, Tag>,
 637         atomic: AtomicReadOp,
 638     ) -> InterpResult<'tcx> {
 639         let this = self.eval_context_mut();
 640
 641         let &[ref place] = check_arg_count(args)?;
 642         let place = this.deref_operand(place)?;
 643
 644         // make sure it fits into a scalar; otherwise it cannot be atomic
 645         let val = this.read_scalar_atomic(&place, atomic)?;
 646
 647         // Check alignment requirements. Atomics must always be aligned to their size,
 648         // even if the type they wrap would be less aligned (e.g. AtomicU64 on 32bit must
 649         // be 8-aligned).
 650         let align = Align::from_bytes(place.layout.size.bytes()).unwrap();
 651         this.memory.check_ptr_access_align(
 652             place.ptr,
 653             place.layout.size,
 654             align,
 655             CheckInAllocMsg::MemoryAccessTest,
 656         )?;
 657         // Perform regular access.
 658         this.write_scalar(val, dest)?;
 659         Ok(())
 660     }
 661
 662     fn atomic_store(
 663         &mut self,
 664         args: &[OpTy<'tcx, Tag>],
 665         atomic: AtomicWriteOp,
 666     ) -> InterpResult<'tcx> {
 667         let this = self.eval_context_mut();
 668
 669         let &[ref place, ref val] = check_arg_count(args)?;
 670         let place = this.deref_operand(place)?;
 671         let val = this.read_scalar(val)?; // make sure it fits into a scalar; otherwise it cannot be atomic
 672
 673         // Check alignment requirements. Atomics must always be aligned to their size,
 674         // even if the type they wrap would be less aligned (e.g. AtomicU64 on 32bit must
 675         // be 8-aligned).
 676         let align = Align::from_bytes(place.layout.size.bytes()).unwrap();
 677         this.memory.check_ptr_access_align(
 678             place.ptr,
 679             place.layout.size,
 680             align,
 681             CheckInAllocMsg::MemoryAccessTest,
 682         )?;
 683
 684         // Perform atomic store
 685         this.write_scalar_atomic(val, &place, atomic)?;
 686         Ok(())
 687     }
 688
 689     fn compiler_fence(
 690         &mut self,
 691         args: &[OpTy<'tcx, Tag>],
 692         atomic: AtomicFenceOp,
 693     ) -> InterpResult<'tcx> {
 694         let &[] = check_arg_count(args)?;
 695         let _ = atomic;
 696         //FIXME: compiler fences are currently ignored
 697         Ok(())
 698     }
 699
 700     fn atomic_fence(
 701         &mut self,
 702         args: &[OpTy<'tcx, Tag>],
 703         atomic: AtomicFenceOp,
 704     ) -> InterpResult<'tcx> {
 705         let this = self.eval_context_mut();
 706         let &[] = check_arg_count(args)?;
 707         this.validate_atomic_fence(atomic)?;
 708         Ok(())
 709     }
 710
 711     fn atomic_op(
 712         &mut self,
 713         args: &[OpTy<'tcx, Tag>],
 714         dest: &PlaceTy<'tcx, Tag>,
 715         atomic_op: AtomicOp,
 716         atomic: AtomicRwOp,
 717     ) -> InterpResult<'tcx> {
 718         let this = self.eval_context_mut();
 719
 720         let &[ref place, ref rhs] = check_arg_count(args)?;
 721         let place = this.deref_operand(place)?;
 722
 723         if !place.layout.ty.is_integral() {
 724             bug!("Atomic arithmetic operations only work on integer types");
 725         }
 726         let rhs = this.read_immediate(rhs)?;
 727
 728         // Check alignment requirements. Atomics must always be aligned to their size,
 729         // even if the type they wrap would be less aligned (e.g. AtomicU64 on 32bit must
 730         // be 8-aligned).
 731         let align = Align::from_bytes(place.layout.size.bytes()).unwrap();
 732         this.memory.check_ptr_access_align(
 733             place.ptr,
 734             place.layout.size,
 735             align,
 736             CheckInAllocMsg::MemoryAccessTest,
 737         )?;
 738
 739         match atomic_op {
 740             AtomicOp::Min => {
 741                 let old = this.atomic_min_max_scalar(&place, rhs, true, atomic)?;
 742                 this.write_immediate(*old, &dest)?; // old value is returned
 743                 Ok(())
 744             }
 745             AtomicOp::Max => {
 746                 let old = this.atomic_min_max_scalar(&place, rhs, false, atomic)?;
 747                 this.write_immediate(*old, &dest)?; // old value is returned
 748                 Ok(())
 749             }
 750             AtomicOp::MirOp(op, neg) => {
 751                 let old = this.atomic_op_immediate(&place, &rhs, op, neg, atomic)?;
 752                 this.write_immediate(*old, dest)?; // old value is returned
 753                 Ok(())
 754             }
 755         }
 756     }
 757
 758     fn atomic_exchange(
 759         &mut self,
 760         args: &[OpTy<'tcx, Tag>],
 761         dest: &PlaceTy<'tcx, Tag>,
 762         atomic: AtomicRwOp,
 763     ) -> InterpResult<'tcx> {
 764         let this = self.eval_context_mut();
 765
 766         let &[ref place, ref new] = check_arg_count(args)?;
 767         let place = this.deref_operand(place)?;
 768         let new = this.read_scalar(new)?;
 769
 770         // Check alignment requirements. Atomics must always be aligned to their size,
 771         // even if the type they wrap would be less aligned (e.g. AtomicU64 on 32bit must
 772         // be 8-aligned).
 773         let align = Align::from_bytes(place.layout.size.bytes()).unwrap();
 774         this.memory.check_ptr_access_align(
 775             place.ptr,
 776             place.layout.size,
 777             align,
 778             CheckInAllocMsg::MemoryAccessTest,
 779         )?;
 780
 781         let old = this.atomic_exchange_scalar(&place, new, atomic)?;
 782         this.write_scalar(old, dest)?; // old value is returned
 783         Ok(())
 784     }
 785
 786     fn atomic_compare_exchange_impl(
 787         &mut self,
 788         args: &[OpTy<'tcx, Tag>],
 789         dest: &PlaceTy<'tcx, Tag>,
 790         success: AtomicRwOp,
 791         fail: AtomicReadOp,
 792         can_fail_spuriously: bool,
 793     ) -> InterpResult<'tcx> {
 794         let this = self.eval_context_mut();
 795
 796         let &[ref place, ref expect_old, ref new] = check_arg_count(args)?;
 797         let place = this.deref_operand(place)?;
 798         let expect_old = this.read_immediate(expect_old)?; // read as immediate for the sake of `binary_op()`
 799         let new = this.read_scalar(new)?;
 800
 801         // Check alignment requirements. Atomics must always be aligned to their size,
 802         // even if the type they wrap would be less aligned (e.g. AtomicU64 on 32bit must
 803         // be 8-aligned).
 804         let align = Align::from_bytes(place.layout.size.bytes()).unwrap();
 805         this.memory.check_ptr_access_align(
 806             place.ptr,
 807             place.layout.size,
 808             align,
 809             CheckInAllocMsg::MemoryAccessTest,
 810         )?;
 811
 812         let old = this.atomic_compare_exchange_scalar(
 813             &place,
 814             &expect_old,
 815             new,
 816             success,
 817             fail,
 818             can_fail_spuriously,
 819         )?;
 820
 821         // Return old value.
 822         this.write_immediate(old, dest)?;
 823         Ok(())
 824     }
 825
 826     fn atomic_compare_exchange(
 827         &mut self,
 828         args: &[OpTy<'tcx, Tag>],
 829         dest: &PlaceTy<'tcx, Tag>,
 830         success: AtomicRwOp,
 831         fail: AtomicReadOp,
 832     ) -> InterpResult<'tcx> {
 833         self.atomic_compare_exchange_impl(args, dest, success, fail, false)
 834     }
 835
 836     fn atomic_compare_exchange_weak(
 837         &mut self,
 838         args: &[OpTy<'tcx, Tag>],
 839         dest: &PlaceTy<'tcx, Tag>,
 840         success: AtomicRwOp,
 841         fail: AtomicReadOp,
 842     ) -> InterpResult<'tcx> {
 843         self.atomic_compare_exchange_impl(args, dest, success, fail, true)
 844     }
 845
 846     fn float_to_int_unchecked<F>(
 847         &self,
 848         f: F,
 849         dest_ty: ty::Ty<'tcx>,
 850     ) -> InterpResult<'tcx, Scalar<Tag>>
 851     where
 852         F: Float + Into<Scalar<Tag>>,
 853     {
 854         let this = self.eval_context_ref();
 855
 856         // Step 1: cut off the fractional part of `f`. The result of this is
 857         // guaranteed to be precisely representable in IEEE floats.
 858         let f = f.round_to_integral(Round::TowardZero).value;
 859
 860         // Step 2: Cast the truncated float to the target integer type and see if we lose any information in this step.
 861         Ok(match dest_ty.kind() {
 862             // Unsigned
 863             ty::Uint(t) => {
 864                 let size = Integer::from_uint_ty(this, *t).size();
 865                 let res = f.to_u128(size.bits_usize());
 866                 if res.status.is_empty() {
 867                     // No status flags means there was no further rounding or other loss of precision.
 868                     Scalar::from_uint(res.value, size)
 869                 } else {
 870                     // `f` was not representable in this integer type.
 871                     throw_ub_format!(
 872                         "`float_to_int_unchecked` intrinsic called on {} which cannot be represented in target type `{:?}`",
 873                         f,
 874                         dest_ty,
 875                     );
 876                 }
 877             }
 878             // Signed
 879             ty::Int(t) => {
 880                 let size = Integer::from_int_ty(this, *t).size();
 881                 let res = f.to_i128(size.bits_usize());
 882                 if res.status.is_empty() {
 883                     // No status flags means there was no further rounding or other loss of precision.
 884                     Scalar::from_int(res.value, size)
 885                 } else {
 886                     // `f` was not representable in this integer type.
 887                     throw_ub_format!(
 888                         "`float_to_int_unchecked` intrinsic called on {} which cannot be represented in target type `{:?}`",
 889                         f,
 890                         dest_ty,
 891                     );
 892                 }
 893             }
 894             // Nothing else
 895             _ => bug!("`float_to_int_unchecked` called with non-int output type {:?}", dest_ty),
 896         })
 897     }
 898 }