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<'a, 'tcx>(
  17     tcx: TyCtxt<'a, 'tcx, '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_from_hir_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         => hir::Unsafety::Normal,
  75         _ => hir::Unsafety::Unsafe,
  76     }
  77 }
  78
  79 /// Remember to add all intrinsics here, in librustc_codegen_llvm/intrinsic.rs,
  80 /// and in libcore/intrinsics.rs
  81 pub fn check_intrinsic_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
  82                                       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 = || {
  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_mut_ref(tcx.mk_region(env_region), va_list_ty)
  92         })
  93     };
  94
  95     let (n_tps, inputs, output, unsafety) = if name.starts_with("atomic_") {
  96         let split : Vec<&str> = name.split('_').collect();
  97         assert!(split.len() >= 2, "Atomic intrinsic in an incorrect format");
  98
  99         //We only care about the operation here
 100         let (n_tps, inputs, output) = match split[1] {
 101             "cxchg" | "cxchgweak" => (1, vec![tcx.mk_mut_ptr(param(0)),
 102                                               param(0),
 103                                               param(0)],
 104                                       tcx.intern_tup(&[param(0), tcx.types.bool])),
 105             "load" => (1, vec![tcx.mk_imm_ptr(param(0))],
 106                        param(0)),
 107             "store" => (1, vec![tcx.mk_mut_ptr(param(0)), param(0)],
 108                         tcx.mk_unit()),
 109
 110             "xchg" | "xadd" | "xsub" | "and"  | "nand" | "or" | "xor" | "max" |
 111             "min"  | "umax" | "umin" => {
 112                 (1, vec![tcx.mk_mut_ptr(param(0)), param(0)],
 113                  param(0))
 114             }
 115             "fence" | "singlethreadfence" => {
 116                 (0, Vec::new(), tcx.mk_unit())
 117             }
 118             op => {
 119                 struct_span_err!(tcx.sess, it.span, E0092,
 120                       "unrecognized atomic operation function: `{}`", op)
 121                   .span_label(it.span, "unrecognized atomic operation")
 122                   .emit();
 123                 return;
 124             }
 125         };
 126         (n_tps, inputs, output, hir::Unsafety::Unsafe)
 127     } else if &name[..] == "abort" || &name[..] == "unreachable" {
 128         (0, Vec::new(), tcx.types.never, hir::Unsafety::Unsafe)
 129     } else {
 130         let unsafety = intrisic_operation_unsafety(&name[..]);
 131         let (n_tps, inputs, output) = match &name[..] {
 132             "breakpoint" => (0, Vec::new(), tcx.mk_unit()),
 133             "size_of" |
 134             "pref_align_of" | "min_align_of" => (1, Vec::new(), tcx.types.usize),
 135             "size_of_val" |  "min_align_of_val" => {
 136                 (1, vec![
 137                     tcx.mk_imm_ref(tcx.mk_region(ty::ReLateBound(ty::INNERMOST,
 138                                                                  ty::BrAnon(0))),
 139                                    param(0))
 140                  ], tcx.types.usize)
 141             }
 142             "rustc_peek" => (1, vec![param(0)], param(0)),
 143             "panic_if_uninhabited" => (1, Vec::new(), tcx.mk_unit()),
 144             "init" => (1, Vec::new(), param(0)),
 145             "uninit" => (1, Vec::new(), param(0)),
 146             "forget" => (1, vec![param(0)], tcx.mk_unit()),
 147             "transmute" => (2, vec![ param(0) ], param(1)),
 148             "move_val_init" => {
 149                 (1,
 150                  vec![
 151                     tcx.mk_mut_ptr(param(0)),
 152                     param(0)
 153                   ],
 154                tcx.mk_unit())
 155             }
 156             "prefetch_read_data" | "prefetch_write_data" |
 157             "prefetch_read_instruction" | "prefetch_write_instruction" => {
 158                 (1, vec![tcx.mk_ptr(ty::TypeAndMut {
 159                           ty: param(0),
 160                           mutbl: hir::MutImmutable
 161                          }), tcx.types.i32],
 162                     tcx.mk_unit())
 163             }
 164             "drop_in_place" => {
 165                 (1, vec![tcx.mk_mut_ptr(param(0))], tcx.mk_unit())
 166             }
 167             "needs_drop" => (1, Vec::new(), tcx.types.bool),
 168
 169             "type_name" => (1, Vec::new(), tcx.mk_static_str()),
 170             "type_id" => (1, Vec::new(), tcx.types.u64),
 171             "offset" | "arith_offset" => {
 172               (1,
 173                vec![
 174                   tcx.mk_ptr(ty::TypeAndMut {
 175                       ty: param(0),
 176                       mutbl: hir::MutImmutable
 177                   }),
 178                   tcx.types.isize
 179                ],
 180                tcx.mk_ptr(ty::TypeAndMut {
 181                    ty: param(0),
 182                    mutbl: hir::MutImmutable
 183                }))
 184             }
 185             "copy" | "copy_nonoverlapping" => {
 186               (1,
 187                vec![
 188                   tcx.mk_ptr(ty::TypeAndMut {
 189                       ty: param(0),
 190                       mutbl: hir::MutImmutable
 191                   }),
 192                   tcx.mk_ptr(ty::TypeAndMut {
 193                       ty: param(0),
 194                       mutbl: hir::MutMutable
 195                   }),
 196                   tcx.types.usize,
 197                ],
 198                tcx.mk_unit())
 199             }
 200             "volatile_copy_memory" | "volatile_copy_nonoverlapping_memory" => {
 201               (1,
 202                vec![
 203                   tcx.mk_ptr(ty::TypeAndMut {
 204                       ty: param(0),
 205                       mutbl: hir::MutMutable
 206                   }),
 207                   tcx.mk_ptr(ty::TypeAndMut {
 208                       ty: param(0),
 209                       mutbl: hir::MutImmutable
 210                   }),
 211                   tcx.types.usize,
 212                ],
 213                tcx.mk_unit())
 214             }
 215             "write_bytes" | "volatile_set_memory" => {
 216               (1,
 217                vec![
 218                   tcx.mk_ptr(ty::TypeAndMut {
 219                       ty: param(0),
 220                       mutbl: hir::MutMutable
 221                   }),
 222                   tcx.types.u8,
 223                   tcx.types.usize,
 224                ],
 225                tcx.mk_unit())
 226             }
 227             "sqrtf32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 228             "sqrtf64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 229             "powif32" => {
 230                (0,
 231                 vec![ tcx.types.f32, tcx.types.i32 ],
 232                 tcx.types.f32)
 233             }
 234             "powif64" => {
 235                (0,
 236                 vec![ tcx.types.f64, tcx.types.i32 ],
 237                 tcx.types.f64)
 238             }
 239             "sinf32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 240             "sinf64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 241             "cosf32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 242             "cosf64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 243             "powf32" => {
 244                (0,
 245                 vec![ tcx.types.f32, tcx.types.f32 ],
 246                 tcx.types.f32)
 247             }
 248             "powf64" => {
 249                (0,
 250                 vec![ tcx.types.f64, tcx.types.f64 ],
 251                 tcx.types.f64)
 252             }
 253             "expf32"   => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 254             "expf64"   => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 255             "exp2f32"  => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 256             "exp2f64"  => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 257             "logf32"   => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 258             "logf64"   => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 259             "log10f32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 260             "log10f64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 261             "log2f32"  => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 262             "log2f64"  => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 263             "fmaf32" => {
 264                 (0,
 265                  vec![ tcx.types.f32, tcx.types.f32, tcx.types.f32 ],
 266                  tcx.types.f32)
 267             }
 268             "fmaf64" => {
 269                 (0,
 270                  vec![ tcx.types.f64, tcx.types.f64, tcx.types.f64 ],
 271                  tcx.types.f64)
 272             }
 273             "fabsf32"      => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 274             "fabsf64"      => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 275             "copysignf32"  => (0, vec![ tcx.types.f32, tcx.types.f32 ], tcx.types.f32),
 276             "copysignf64"  => (0, vec![ tcx.types.f64, tcx.types.f64 ], tcx.types.f64),
 277             "floorf32"     => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 278             "floorf64"     => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 279             "ceilf32"      => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 280             "ceilf64"      => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 281             "truncf32"     => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 282             "truncf64"     => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 283             "rintf32"      => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 284             "rintf64"      => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 285             "nearbyintf32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 286             "nearbyintf64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 287             "roundf32"     => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 288             "roundf64"     => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 289
 290             "volatile_load" | "unaligned_volatile_load" =>
 291                 (1, vec![ tcx.mk_imm_ptr(param(0)) ], param(0)),
 292             "volatile_store" | "unaligned_volatile_store" =>
 293                 (1, vec![ tcx.mk_mut_ptr(param(0)), param(0) ], tcx.mk_unit()),
 294
 295             "ctpop" | "ctlz" | "ctlz_nonzero" | "cttz" | "cttz_nonzero" |
 296             "bswap" | "bitreverse" =>
 297                 (1, vec![param(0)], param(0)),
 298
 299             "add_with_overflow" | "sub_with_overflow"  | "mul_with_overflow" =>
 300                 (1, vec![param(0), param(0)],
 301                 tcx.intern_tup(&[param(0), tcx.types.bool])),
 302
 303             "unchecked_div" | "unchecked_rem" | "exact_div" =>
 304                 (1, vec![param(0), param(0)], param(0)),
 305             "unchecked_shl" | "unchecked_shr" |
 306             "rotate_left" | "rotate_right" =>
 307                 (1, vec![param(0), param(0)], param(0)),
 308             "unchecked_add" | "unchecked_sub" | "unchecked_mul" =>
 309                 (1, vec![param(0), param(0)], param(0)),
 310             "overflowing_add" | "overflowing_sub" | "overflowing_mul" =>
 311                 (1, vec![param(0), param(0)], param(0)),
 312             "saturating_add" | "saturating_sub" =>
 313                 (1, vec![param(0), param(0)], param(0)),
 314             "fadd_fast" | "fsub_fast" | "fmul_fast" | "fdiv_fast" | "frem_fast" =>
 315                 (1, vec![param(0), param(0)], param(0)),
 316
 317             "assume" => (0, vec![tcx.types.bool], tcx.mk_unit()),
 318             "likely" => (0, vec![tcx.types.bool], tcx.types.bool),
 319             "unlikely" => (0, vec![tcx.types.bool], tcx.types.bool),
 320
 321             "discriminant_value" => (1, vec![
 322                     tcx.mk_imm_ref(tcx.mk_region(ty::ReLateBound(ty::INNERMOST,
 323                                                                  ty::BrAnon(0))),
 324                                    param(0))], tcx.types.u64),
 325
 326             "try" => {
 327                 let mut_u8 = tcx.mk_mut_ptr(tcx.types.u8);
 328                 let fn_ty = ty::Binder::bind(tcx.mk_fn_sig(
 329                     iter::once(mut_u8),
 330                     tcx.mk_unit(),
 331                     false,
 332                     hir::Unsafety::Normal,
 333                     Abi::Rust,
 334                 ));
 335                 (0, vec![tcx.mk_fn_ptr(fn_ty), mut_u8, mut_u8], tcx.types.i32)
 336             }
 337
 338             "va_start" | "va_end" => {
 339                 match mk_va_list_ty() {
 340                     Some(va_list_ty) => (0, vec![va_list_ty], tcx.mk_unit()),
 341                     None => bug!("`va_list` language item needed for C-variadic intrinsics")
 342                 }
 343             }
 344
 345             "va_copy" => {
 346                 match tcx.lang_items().va_list() {
 347                     Some(did) => {
 348                         let region = tcx.mk_region(ty::ReLateBound(ty::INNERMOST, ty::BrAnon(0)));
 349                         let env_region = ty::ReLateBound(ty::INNERMOST, ty::BrEnv);
 350                         let va_list_ty = tcx.type_of(did).subst(tcx, &[region.into()]);
 351                         let ret_ty = match va_list_ty.sty {
 352                             ty::Adt(def, _) if def.is_struct() => {
 353                                 let fields = &def.non_enum_variant().fields;
 354                                 match tcx.type_of(fields[0].did).subst(tcx, &[region.into()]).sty {
 355                                     ty::Ref(_, element_ty, _) => match element_ty.sty {
 356                                         ty::Adt(..) => element_ty,
 357                                         _ => va_list_ty
 358                                     }
 359                                     _ => bug!("va_list structure is invalid")
 360                                 }
 361                             }
 362                             _ => {
 363                                 bug!("va_list structure is invalid")
 364                             }
 365                         };
 366                         (0, vec![tcx.mk_imm_ref(tcx.mk_region(env_region), va_list_ty)], ret_ty)
 367                     }
 368                     None => bug!("`va_list` language item needed for C-variadic intrinsics")
 369                 }
 370             }
 371
 372             "va_arg" => {
 373                 match mk_va_list_ty() {
 374                     Some(va_list_ty) => (1, vec![va_list_ty], param(0)),
 375                     None => bug!("`va_list` language item needed for C-variadic intrinsics")
 376                 }
 377             }
 378
 379             "nontemporal_store" => {
 380                 (1, vec![ tcx.mk_mut_ptr(param(0)), param(0) ], tcx.mk_unit())
 381             }
 382
 383             ref other => {
 384                 struct_span_err!(tcx.sess, it.span, E0093,
 385                                  "unrecognized intrinsic function: `{}`",
 386                                  *other)
 387                                  .span_label(it.span, "unrecognized intrinsic")
 388                                  .emit();
 389                 return;
 390             }
 391         };
 392         (n_tps, inputs, output, unsafety)
 393     };
 394     equate_intrinsic_type(tcx, it, n_tps, Abi::RustIntrinsic, unsafety, inputs, output)
 395 }
 396
 397 /// Type-check `extern "platform-intrinsic" { ... }` functions.
 398 pub fn check_platform_intrinsic_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 399                                                it: &hir::ForeignItem) {
 400     let param = |n| {
 401         let name = InternedString::intern(&format!("P{}", n));
 402         tcx.mk_ty_param(n, name)
 403     };
 404
 405     let name = it.ident.as_str();
 406
 407     let (n_tps, inputs, output) = match &*name {
 408         "simd_eq" | "simd_ne" | "simd_lt" | "simd_le" | "simd_gt" | "simd_ge" => {
 409             (2, vec![param(0), param(0)], param(1))
 410         }
 411         "simd_add" | "simd_sub" | "simd_mul" | "simd_rem" |
 412         "simd_div" | "simd_shl" | "simd_shr" |
 413         "simd_and" | "simd_or" | "simd_xor" |
 414         "simd_fmin" | "simd_fmax" | "simd_fpow" |
 415         "simd_saturating_add" | "simd_saturating_sub" => {
 416             (1, vec![param(0), param(0)], param(0))
 417         }
 418         "simd_fsqrt" | "simd_fsin" | "simd_fcos" | "simd_fexp" | "simd_fexp2" |
 419         "simd_flog2" | "simd_flog10" | "simd_flog" |
 420         "simd_fabs" | "simd_floor" | "simd_ceil" => {
 421             (1, vec![param(0)], param(0))
 422         }
 423         "simd_fpowi" => {
 424             (1, vec![param(0), tcx.types.i32], param(0))
 425         }
 426         "simd_fma" => {
 427             (1, vec![param(0), param(0), param(0)], param(0))
 428         }
 429         "simd_gather" => {
 430             (3, vec![param(0), param(1), param(2)], param(0))
 431         }
 432         "simd_scatter" => {
 433             (3, vec![param(0), param(1), param(2)], tcx.mk_unit())
 434         }
 435         "simd_insert" => (2, vec![param(0), tcx.types.u32, param(1)], param(0)),
 436         "simd_extract" => (2, vec![param(0), tcx.types.u32], param(1)),
 437         "simd_cast" => (2, vec![param(0)], param(1)),
 438         "simd_bitmask" => (2, vec![param(0)], param(1)),
 439         "simd_select" |
 440         "simd_select_bitmask" => (2, vec![param(0), param(1), param(1)], param(1)),
 441         "simd_reduce_all" | "simd_reduce_any" => (1, vec![param(0)], tcx.types.bool),
 442         "simd_reduce_add_ordered" | "simd_reduce_mul_ordered"
 443             => (2, vec![param(0), param(1)], param(1)),
 444         "simd_reduce_add_unordered" | "simd_reduce_mul_unordered" |
 445         "simd_reduce_and" | "simd_reduce_or"  | "simd_reduce_xor" |
 446         "simd_reduce_min" | "simd_reduce_max" |
 447         "simd_reduce_min_nanless" | "simd_reduce_max_nanless"
 448             => (2, vec![param(0)], param(1)),
 449         name if name.starts_with("simd_shuffle") => {
 450             match name["simd_shuffle".len()..].parse() {
 451                 Ok(n) => {
 452                     let params = vec![param(0), param(0),
 453                                       tcx.mk_array(tcx.types.u32, n)];
 454                     (2, params, param(1))
 455                 }
 456                 Err(_) => {
 457                     span_err!(tcx.sess, it.span, E0439,
 458                               "invalid `simd_shuffle`, needs length: `{}`", name);
 459                     return
 460                 }
 461             }
 462         }
 463         _ => {
 464             let msg = format!("unrecognized platform-specific intrinsic function: `{}`", name);
 465             tcx.sess.span_err(it.span, &msg);
 466             return;
 467         }
 468     };
 469
 470     equate_intrinsic_type(tcx, it, n_tps, Abi::PlatformIntrinsic, hir::Unsafety::Unsafe,
 471                           inputs, output)
 472 }