src/librustc_typeck/check/intrinsic.rs

   1 //! Type-checking for the rust-intrinsic and platform-intrinsic
   2 //! intrinsics that the compiler exposes.
   3
   4 use rustc::traits::{ObligationCause, ObligationCauseCode};
   5 use rustc::ty::{self, TyCtxt, Ty};
   6 use rustc::ty::subst::Subst;
   7 use crate::require_same_types;
   8
   9 use rustc_target::spec::abi::Abi;
  10 use syntax::symbol::InternedString;
  11
  12 use rustc::hir;
  13
  14 use std::iter;
  15
  16 fn equate_intrinsic_type<'tcx>(
  17     tcx: TyCtxt<'tcx>,
  18     it: &hir::ForeignItem,
  19     n_tps: usize,
  20     abi: Abi,
  21     safety: hir::Unsafety,
  22     inputs: Vec<Ty<'tcx>>,
  23     output: Ty<'tcx>,
  24 ) {
  25     let def_id = tcx.hir().local_def_id(it.hir_id);
  26
  27     match it.node {
  28         hir::ForeignItemKind::Fn(..) => {}
  29         _ => {
  30             struct_span_err!(tcx.sess, it.span, E0622,
  31                              "intrinsic must be a function")
  32                 .span_label(it.span, "expected a function")
  33                 .emit();
  34             return;
  35         }
  36     }
  37
  38     let i_n_tps = tcx.generics_of(def_id).own_counts().types;
  39     if i_n_tps != n_tps {
  40         let span = match it.node {
  41             hir::ForeignItemKind::Fn(_, _, ref generics) => generics.span,
  42             _ => bug!()
  43         };
  44
  45         struct_span_err!(tcx.sess, span, E0094,
  46                         "intrinsic has wrong number of type \
  47                          parameters: found {}, expected {}",
  48                         i_n_tps, n_tps)
  49             .span_label(span, format!("expected {} type parameter", n_tps))
  50             .emit();
  51         return;
  52     }
  53
  54     let fty = tcx.mk_fn_ptr(ty::Binder::bind(tcx.mk_fn_sig(
  55         inputs.into_iter(),
  56         output,
  57         false,
  58         safety,
  59         abi
  60     )));
  61     let cause = ObligationCause::new(it.span, it.hir_id, ObligationCauseCode::IntrinsicType);
  62     require_same_types(tcx, &cause, tcx.mk_fn_ptr(tcx.fn_sig(def_id)), fty);
  63 }
  64
  65 /// Returns `true` if the given intrinsic is unsafe to call or not.
  66 pub fn intrisic_operation_unsafety(intrinsic: &str) -> hir::Unsafety {
  67     match intrinsic {
  68         "size_of" | "min_align_of" | "needs_drop" |
  69         "add_with_overflow" | "sub_with_overflow" | "mul_with_overflow" |
  70         "overflowing_add" | "overflowing_sub" | "overflowing_mul" |
  71         "saturating_add" | "saturating_sub" |
  72         "rotate_left" | "rotate_right" |
  73         "ctpop" | "ctlz" | "cttz" | "bswap" | "bitreverse" |
  74         "minnumf32" | "minnumf64" | "maxnumf32" | "maxnumf64"
  75         => hir::Unsafety::Normal,
  76         _ => hir::Unsafety::Unsafe,
  77     }
  78 }
  79
  80 /// Remember to add all intrinsics here, in librustc_codegen_llvm/intrinsic.rs,
  81 /// and in libcore/intrinsics.rs
  82 pub fn check_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem) {
  83     let param = |n| tcx.mk_ty_param(n, InternedString::intern(&format!("P{}", n)));
  84     let name = it.ident.as_str();
  85
  86     let mk_va_list_ty = |mutbl| {
  87         tcx.lang_items().va_list().map(|did| {
  88             let region = tcx.mk_region(ty::ReLateBound(ty::INNERMOST, ty::BrAnon(0)));
  89             let env_region = ty::ReLateBound(ty::INNERMOST, ty::BrEnv);
  90             let va_list_ty = tcx.type_of(did).subst(tcx, &[region.into()]);
  91             (tcx.mk_ref(tcx.mk_region(env_region), ty::TypeAndMut {
  92                 ty: va_list_ty,
  93                 mutbl
  94             }), va_list_ty)
  95         })
  96     };
  97
  98     let (n_tps, inputs, output, unsafety) = if name.starts_with("atomic_") {
  99         let split : Vec<&str> = name.split('_').collect();
 100         assert!(split.len() >= 2, "Atomic intrinsic in an incorrect format");
 101
 102         //We only care about the operation here
 103         let (n_tps, inputs, output) = match split[1] {
 104             "cxchg" | "cxchgweak" => (1, vec![tcx.mk_mut_ptr(param(0)),
 105                                               param(0),
 106                                               param(0)],
 107                                       tcx.intern_tup(&[param(0), tcx.types.bool])),
 108             "load" => (1, vec![tcx.mk_imm_ptr(param(0))],
 109                        param(0)),
 110             "store" => (1, vec![tcx.mk_mut_ptr(param(0)), param(0)],
 111                         tcx.mk_unit()),
 112
 113             "xchg" | "xadd" | "xsub" | "and"  | "nand" | "or" | "xor" | "max" |
 114             "min"  | "umax" | "umin" => {
 115                 (1, vec![tcx.mk_mut_ptr(param(0)), param(0)],
 116                  param(0))
 117             }
 118             "fence" | "singlethreadfence" => {
 119                 (0, Vec::new(), tcx.mk_unit())
 120             }
 121             op => {
 122                 struct_span_err!(tcx.sess, it.span, E0092,
 123                       "unrecognized atomic operation function: `{}`", op)
 124                   .span_label(it.span, "unrecognized atomic operation")
 125                   .emit();
 126                 return;
 127             }
 128         };
 129         (n_tps, inputs, output, hir::Unsafety::Unsafe)
 130     } else if &name[..] == "abort" || &name[..] == "unreachable" {
 131         (0, Vec::new(), tcx.types.never, hir::Unsafety::Unsafe)
 132     } else {
 133         let unsafety = intrisic_operation_unsafety(&name[..]);
 134         let (n_tps, inputs, output) = match &name[..] {
 135             "breakpoint" => (0, Vec::new(), tcx.mk_unit()),
 136             "size_of" |
 137             "pref_align_of" | "min_align_of" => (1, Vec::new(), tcx.types.usize),
 138             "size_of_val" |  "min_align_of_val" => {
 139                 (1, vec![
 140                     tcx.mk_imm_ref(tcx.mk_region(ty::ReLateBound(ty::INNERMOST,
 141                                                                  ty::BrAnon(0))),
 142                                    param(0))
 143                  ], tcx.types.usize)
 144             }
 145             "rustc_peek" => (1, vec![param(0)], param(0)),
 146             "panic_if_uninhabited" => (1, Vec::new(), tcx.mk_unit()),
 147             "init" => (1, Vec::new(), param(0)),
 148             "forget" => (1, vec![param(0)], tcx.mk_unit()),
 149             "transmute" => (2, vec![ param(0) ], param(1)),
 150             "move_val_init" => {
 151                 (1,
 152                  vec![
 153                     tcx.mk_mut_ptr(param(0)),
 154                     param(0)
 155                   ],
 156                tcx.mk_unit())
 157             }
 158             "prefetch_read_data" | "prefetch_write_data" |
 159             "prefetch_read_instruction" | "prefetch_write_instruction" => {
 160                 (1, vec![tcx.mk_ptr(ty::TypeAndMut {
 161                           ty: param(0),
 162                           mutbl: hir::MutImmutable
 163                          }), tcx.types.i32],
 164                     tcx.mk_unit())
 165             }
 166             "drop_in_place" => {
 167                 (1, vec![tcx.mk_mut_ptr(param(0))], tcx.mk_unit())
 168             }
 169             "needs_drop" => (1, Vec::new(), tcx.types.bool),
 170
 171             "type_name" => (1, Vec::new(), tcx.mk_static_str()),
 172             "type_id" => (1, Vec::new(), tcx.types.u64),
 173             "offset" | "arith_offset" => {
 174               (1,
 175                vec![
 176                   tcx.mk_ptr(ty::TypeAndMut {
 177                       ty: param(0),
 178                       mutbl: hir::MutImmutable
 179                   }),
 180                   tcx.types.isize
 181                ],
 182                tcx.mk_ptr(ty::TypeAndMut {
 183                    ty: param(0),
 184                    mutbl: hir::MutImmutable
 185                }))
 186             }
 187             "copy" | "copy_nonoverlapping" => {
 188               (1,
 189                vec![
 190                   tcx.mk_ptr(ty::TypeAndMut {
 191                       ty: param(0),
 192                       mutbl: hir::MutImmutable
 193                   }),
 194                   tcx.mk_ptr(ty::TypeAndMut {
 195                       ty: param(0),
 196                       mutbl: hir::MutMutable
 197                   }),
 198                   tcx.types.usize,
 199                ],
 200                tcx.mk_unit())
 201             }
 202             "volatile_copy_memory" | "volatile_copy_nonoverlapping_memory" => {
 203               (1,
 204                vec![
 205                   tcx.mk_ptr(ty::TypeAndMut {
 206                       ty: param(0),
 207                       mutbl: hir::MutMutable
 208                   }),
 209                   tcx.mk_ptr(ty::TypeAndMut {
 210                       ty: param(0),
 211                       mutbl: hir::MutImmutable
 212                   }),
 213                   tcx.types.usize,
 214                ],
 215                tcx.mk_unit())
 216             }
 217             "write_bytes" | "volatile_set_memory" => {
 218               (1,
 219                vec![
 220                   tcx.mk_ptr(ty::TypeAndMut {
 221                       ty: param(0),
 222                       mutbl: hir::MutMutable
 223                   }),
 224                   tcx.types.u8,
 225                   tcx.types.usize,
 226                ],
 227                tcx.mk_unit())
 228             }
 229             "sqrtf32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 230             "sqrtf64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 231             "powif32" => {
 232                (0,
 233                 vec![ tcx.types.f32, tcx.types.i32 ],
 234                 tcx.types.f32)
 235             }
 236             "powif64" => {
 237                (0,
 238                 vec![ tcx.types.f64, tcx.types.i32 ],
 239                 tcx.types.f64)
 240             }
 241             "sinf32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 242             "sinf64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 243             "cosf32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 244             "cosf64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 245             "powf32" => {
 246                (0,
 247                 vec![ tcx.types.f32, tcx.types.f32 ],
 248                 tcx.types.f32)
 249             }
 250             "powf64" => {
 251                (0,
 252                 vec![ tcx.types.f64, tcx.types.f64 ],
 253                 tcx.types.f64)
 254             }
 255             "expf32"   => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 256             "expf64"   => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 257             "exp2f32"  => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 258             "exp2f64"  => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 259             "logf32"   => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 260             "logf64"   => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 261             "log10f32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 262             "log10f64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 263             "log2f32"  => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 264             "log2f64"  => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 265             "fmaf32" => {
 266                 (0,
 267                  vec![ tcx.types.f32, tcx.types.f32, tcx.types.f32 ],
 268                  tcx.types.f32)
 269             }
 270             "fmaf64" => {
 271                 (0,
 272                  vec![ tcx.types.f64, tcx.types.f64, tcx.types.f64 ],
 273                  tcx.types.f64)
 274             }
 275             "fabsf32"      => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 276             "fabsf64"      => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 277             "minnumf32"    => (0, vec![ tcx.types.f32, tcx.types.f32 ], tcx.types.f32),
 278             "minnumf64"    => (0, vec![ tcx.types.f64, tcx.types.f64 ], tcx.types.f64),
 279             "maxnumf32"    => (0, vec![ tcx.types.f32, tcx.types.f32 ], tcx.types.f32),
 280             "maxnumf64"    => (0, vec![ tcx.types.f64, tcx.types.f64 ], tcx.types.f64),
 281             "copysignf32"  => (0, vec![ tcx.types.f32, tcx.types.f32 ], tcx.types.f32),
 282             "copysignf64"  => (0, vec![ tcx.types.f64, tcx.types.f64 ], tcx.types.f64),
 283             "floorf32"     => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 284             "floorf64"     => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 285             "ceilf32"      => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 286             "ceilf64"      => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 287             "truncf32"     => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 288             "truncf64"     => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 289             "rintf32"      => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 290             "rintf64"      => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 291             "nearbyintf32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 292             "nearbyintf64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 293             "roundf32"     => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 294             "roundf64"     => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 295
 296             "volatile_load" | "unaligned_volatile_load" =>
 297                 (1, vec![ tcx.mk_imm_ptr(param(0)) ], param(0)),
 298             "volatile_store" | "unaligned_volatile_store" =>
 299                 (1, vec![ tcx.mk_mut_ptr(param(0)), param(0) ], tcx.mk_unit()),
 300
 301             "ctpop" | "ctlz" | "ctlz_nonzero" | "cttz" | "cttz_nonzero" |
 302             "bswap" | "bitreverse" =>
 303                 (1, vec![param(0)], param(0)),
 304
 305             "add_with_overflow" | "sub_with_overflow"  | "mul_with_overflow" =>
 306                 (1, vec![param(0), param(0)],
 307                 tcx.intern_tup(&[param(0), tcx.types.bool])),
 308
 309             "unchecked_div" | "unchecked_rem" | "exact_div" =>
 310                 (1, vec![param(0), param(0)], param(0)),
 311             "unchecked_shl" | "unchecked_shr" |
 312             "rotate_left" | "rotate_right" =>
 313                 (1, vec![param(0), param(0)], param(0)),
 314             "unchecked_add" | "unchecked_sub" | "unchecked_mul" =>
 315                 (1, vec![param(0), param(0)], param(0)),
 316             "overflowing_add" | "overflowing_sub" | "overflowing_mul" =>
 317                 (1, vec![param(0), param(0)], param(0)),
 318             "saturating_add" | "saturating_sub" =>
 319                 (1, vec![param(0), param(0)], param(0)),
 320             "fadd_fast" | "fsub_fast" | "fmul_fast" | "fdiv_fast" | "frem_fast" =>
 321                 (1, vec![param(0), param(0)], param(0)),
 322
 323             "assume" => (0, vec![tcx.types.bool], tcx.mk_unit()),
 324             "likely" => (0, vec![tcx.types.bool], tcx.types.bool),
 325             "unlikely" => (0, vec![tcx.types.bool], tcx.types.bool),
 326
 327             "discriminant_value" => (1, vec![
 328                     tcx.mk_imm_ref(tcx.mk_region(ty::ReLateBound(ty::INNERMOST,
 329                                                                  ty::BrAnon(0))),
 330                                    param(0))], tcx.types.u64),
 331
 332             "try" => {
 333                 let mut_u8 = tcx.mk_mut_ptr(tcx.types.u8);
 334                 let fn_ty = ty::Binder::bind(tcx.mk_fn_sig(
 335                     iter::once(mut_u8),
 336                     tcx.mk_unit(),
 337                     false,
 338                     hir::Unsafety::Normal,
 339                     Abi::Rust,
 340                 ));
 341                 (0, vec![tcx.mk_fn_ptr(fn_ty), mut_u8, mut_u8], tcx.types.i32)
 342             }
 343
 344             "va_start" | "va_end" => {
 345                 match mk_va_list_ty(hir::MutMutable) {
 346                     Some((va_list_ref_ty, _)) => (0, vec![va_list_ref_ty], tcx.mk_unit()),
 347                     None => bug!("`va_list` language item needed for C-variadic intrinsics")
 348                 }
 349             }
 350
 351             "va_copy" => {
 352                 match mk_va_list_ty(hir::MutImmutable) {
 353                     Some((va_list_ref_ty, va_list_ty)) => {
 354                         let va_list_ptr_ty = tcx.mk_mut_ptr(va_list_ty);
 355                         (0, vec![va_list_ptr_ty, va_list_ref_ty], tcx.mk_unit())
 356                     }
 357                     None => bug!("`va_list` language item needed for C-variadic intrinsics")
 358                 }
 359             }
 360
 361             "va_arg" => {
 362                 match mk_va_list_ty(hir::MutMutable) {
 363                     Some((va_list_ref_ty, _)) => (1, vec![va_list_ref_ty], param(0)),
 364                     None => bug!("`va_list` language item needed for C-variadic intrinsics")
 365                 }
 366             }
 367
 368             "nontemporal_store" => {
 369                 (1, vec![ tcx.mk_mut_ptr(param(0)), param(0) ], tcx.mk_unit())
 370             }
 371
 372             ref other => {
 373                 struct_span_err!(tcx.sess, it.span, E0093,
 374                                  "unrecognized intrinsic function: `{}`",
 375                                  *other)
 376                                  .span_label(it.span, "unrecognized intrinsic")
 377                                  .emit();
 378                 return;
 379             }
 380         };
 381         (n_tps, inputs, output, unsafety)
 382     };
 383     equate_intrinsic_type(tcx, it, n_tps, Abi::RustIntrinsic, unsafety, inputs, output)
 384 }
 385
 386 /// Type-check `extern "platform-intrinsic" { ... }` functions.
 387 pub fn check_platform_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem) {
 388     let param = |n| {
 389         let name = InternedString::intern(&format!("P{}", n));
 390         tcx.mk_ty_param(n, name)
 391     };
 392
 393     let name = it.ident.as_str();
 394
 395     let (n_tps, inputs, output) = match &*name {
 396         "simd_eq" | "simd_ne" | "simd_lt" | "simd_le" | "simd_gt" | "simd_ge" => {
 397             (2, vec![param(0), param(0)], param(1))
 398         }
 399         "simd_add" | "simd_sub" | "simd_mul" | "simd_rem" |
 400         "simd_div" | "simd_shl" | "simd_shr" |
 401         "simd_and" | "simd_or" | "simd_xor" |
 402         "simd_fmin" | "simd_fmax" | "simd_fpow" |
 403         "simd_saturating_add" | "simd_saturating_sub" => {
 404             (1, vec![param(0), param(0)], param(0))
 405         }
 406         "simd_fsqrt" | "simd_fsin" | "simd_fcos" | "simd_fexp" | "simd_fexp2" |
 407         "simd_flog2" | "simd_flog10" | "simd_flog" |
 408         "simd_fabs" | "simd_floor" | "simd_ceil" => {
 409             (1, vec![param(0)], param(0))
 410         }
 411         "simd_fpowi" => {
 412             (1, vec![param(0), tcx.types.i32], param(0))
 413         }
 414         "simd_fma" => {
 415             (1, vec![param(0), param(0), param(0)], param(0))
 416         }
 417         "simd_gather" => {
 418             (3, vec![param(0), param(1), param(2)], param(0))
 419         }
 420         "simd_scatter" => {
 421             (3, vec![param(0), param(1), param(2)], tcx.mk_unit())
 422         }
 423         "simd_insert" => (2, vec![param(0), tcx.types.u32, param(1)], param(0)),
 424         "simd_extract" => (2, vec![param(0), tcx.types.u32], param(1)),
 425         "simd_cast" => (2, vec![param(0)], param(1)),
 426         "simd_bitmask" => (2, vec![param(0)], param(1)),
 427         "simd_select" |
 428         "simd_select_bitmask" => (2, vec![param(0), param(1), param(1)], param(1)),
 429         "simd_reduce_all" | "simd_reduce_any" => (1, vec![param(0)], tcx.types.bool),
 430         "simd_reduce_add_ordered" | "simd_reduce_mul_ordered"
 431             => (2, vec![param(0), param(1)], param(1)),
 432         "simd_reduce_add_unordered" | "simd_reduce_mul_unordered" |
 433         "simd_reduce_and" | "simd_reduce_or"  | "simd_reduce_xor" |
 434         "simd_reduce_min" | "simd_reduce_max" |
 435         "simd_reduce_min_nanless" | "simd_reduce_max_nanless"
 436             => (2, vec![param(0)], param(1)),
 437         name if name.starts_with("simd_shuffle") => {
 438             match name["simd_shuffle".len()..].parse() {
 439                 Ok(n) => {
 440                     let params = vec![param(0), param(0),
 441                                       tcx.mk_array(tcx.types.u32, n)];
 442                     (2, params, param(1))
 443                 }
 444                 Err(_) => {
 445                     span_err!(tcx.sess, it.span, E0439,
 446                               "invalid `simd_shuffle`, needs length: `{}`", name);
 447                     return
 448                 }
 449             }
 450         }
 451         _ => {
 452             let msg = format!("unrecognized platform-specific intrinsic function: `{}`", name);
 453             tcx.sess.span_err(it.span, &msg);
 454             return;
 455         }
 456     };
 457
 458     equate_intrinsic_type(tcx, it, n_tps, Abi::PlatformIntrinsic, hir::Unsafety::Unsafe,
 459                           inputs, output)
 460 }