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         "wrapping_add" | "wrapping_sub" | "wrapping_mul" |
  71         "saturating_add" | "saturating_sub" |
  72         "rotate_left" | "rotate_right" |
  73         "ctpop" | "ctlz" | "cttz" | "bswap" | "bitreverse" |
  74         "minnumf32" | "minnumf64" | "maxnumf32" | "maxnumf64" | "type_name"
  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             "uninit" => (1, Vec::new(), param(0)),
 149             "forget" => (1, vec![param(0)], tcx.mk_unit()),
 150             "transmute" => (2, vec![ param(0) ], param(1)),
 151             "move_val_init" => {
 152                 (1,
 153                  vec![
 154                     tcx.mk_mut_ptr(param(0)),
 155                     param(0)
 156                   ],
 157                tcx.mk_unit())
 158             }
 159             "prefetch_read_data" | "prefetch_write_data" |
 160             "prefetch_read_instruction" | "prefetch_write_instruction" => {
 161                 (1, vec![tcx.mk_ptr(ty::TypeAndMut {
 162                           ty: param(0),
 163                           mutbl: hir::MutImmutable
 164                          }), tcx.types.i32],
 165                     tcx.mk_unit())
 166             }
 167             "drop_in_place" => {
 168                 (1, vec![tcx.mk_mut_ptr(param(0))], tcx.mk_unit())
 169             }
 170             "needs_drop" => (1, Vec::new(), tcx.types.bool),
 171
 172             "type_name" => (1, Vec::new(), tcx.mk_static_str()),
 173             "type_id" => (1, Vec::new(), tcx.types.u64),
 174             "offset" | "arith_offset" => {
 175               (1,
 176                vec![
 177                   tcx.mk_ptr(ty::TypeAndMut {
 178                       ty: param(0),
 179                       mutbl: hir::MutImmutable
 180                   }),
 181                   tcx.types.isize
 182                ],
 183                tcx.mk_ptr(ty::TypeAndMut {
 184                    ty: param(0),
 185                    mutbl: hir::MutImmutable
 186                }))
 187             }
 188             "copy" | "copy_nonoverlapping" => {
 189               (1,
 190                vec![
 191                   tcx.mk_ptr(ty::TypeAndMut {
 192                       ty: param(0),
 193                       mutbl: hir::MutImmutable
 194                   }),
 195                   tcx.mk_ptr(ty::TypeAndMut {
 196                       ty: param(0),
 197                       mutbl: hir::MutMutable
 198                   }),
 199                   tcx.types.usize,
 200                ],
 201                tcx.mk_unit())
 202             }
 203             "volatile_copy_memory" | "volatile_copy_nonoverlapping_memory" => {
 204               (1,
 205                vec![
 206                   tcx.mk_ptr(ty::TypeAndMut {
 207                       ty: param(0),
 208                       mutbl: hir::MutMutable
 209                   }),
 210                   tcx.mk_ptr(ty::TypeAndMut {
 211                       ty: param(0),
 212                       mutbl: hir::MutImmutable
 213                   }),
 214                   tcx.types.usize,
 215                ],
 216                tcx.mk_unit())
 217             }
 218             "write_bytes" | "volatile_set_memory" => {
 219               (1,
 220                vec![
 221                   tcx.mk_ptr(ty::TypeAndMut {
 222                       ty: param(0),
 223                       mutbl: hir::MutMutable
 224                   }),
 225                   tcx.types.u8,
 226                   tcx.types.usize,
 227                ],
 228                tcx.mk_unit())
 229             }
 230             "sqrtf32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 231             "sqrtf64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 232             "powif32" => {
 233                (0,
 234                 vec![ tcx.types.f32, tcx.types.i32 ],
 235                 tcx.types.f32)
 236             }
 237             "powif64" => {
 238                (0,
 239                 vec![ tcx.types.f64, tcx.types.i32 ],
 240                 tcx.types.f64)
 241             }
 242             "sinf32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 243             "sinf64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 244             "cosf32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 245             "cosf64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 246             "powf32" => {
 247                (0,
 248                 vec![ tcx.types.f32, tcx.types.f32 ],
 249                 tcx.types.f32)
 250             }
 251             "powf64" => {
 252                (0,
 253                 vec![ tcx.types.f64, tcx.types.f64 ],
 254                 tcx.types.f64)
 255             }
 256             "expf32"   => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 257             "expf64"   => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 258             "exp2f32"  => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 259             "exp2f64"  => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 260             "logf32"   => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 261             "logf64"   => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 262             "log10f32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 263             "log10f64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 264             "log2f32"  => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 265             "log2f64"  => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 266             "fmaf32" => {
 267                 (0,
 268                  vec![ tcx.types.f32, tcx.types.f32, tcx.types.f32 ],
 269                  tcx.types.f32)
 270             }
 271             "fmaf64" => {
 272                 (0,
 273                  vec![ tcx.types.f64, tcx.types.f64, tcx.types.f64 ],
 274                  tcx.types.f64)
 275             }
 276             "fabsf32"      => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 277             "fabsf64"      => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 278             "minnumf32"    => (0, vec![ tcx.types.f32, tcx.types.f32 ], tcx.types.f32),
 279             "minnumf64"    => (0, vec![ tcx.types.f64, tcx.types.f64 ], tcx.types.f64),
 280             "maxnumf32"    => (0, vec![ tcx.types.f32, tcx.types.f32 ], tcx.types.f32),
 281             "maxnumf64"    => (0, vec![ tcx.types.f64, tcx.types.f64 ], tcx.types.f64),
 282             "copysignf32"  => (0, vec![ tcx.types.f32, tcx.types.f32 ], tcx.types.f32),
 283             "copysignf64"  => (0, vec![ tcx.types.f64, tcx.types.f64 ], tcx.types.f64),
 284             "floorf32"     => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 285             "floorf64"     => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 286             "ceilf32"      => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 287             "ceilf64"      => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 288             "truncf32"     => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 289             "truncf64"     => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 290             "rintf32"      => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 291             "rintf64"      => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 292             "nearbyintf32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 293             "nearbyintf64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 294             "roundf32"     => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 295             "roundf64"     => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 296
 297             "volatile_load" | "unaligned_volatile_load" =>
 298                 (1, vec![ tcx.mk_imm_ptr(param(0)) ], param(0)),
 299             "volatile_store" | "unaligned_volatile_store" =>
 300                 (1, vec![ tcx.mk_mut_ptr(param(0)), param(0) ], tcx.mk_unit()),
 301
 302             "ctpop" | "ctlz" | "ctlz_nonzero" | "cttz" | "cttz_nonzero" |
 303             "bswap" | "bitreverse" =>
 304                 (1, vec![param(0)], param(0)),
 305
 306             "add_with_overflow" | "sub_with_overflow"  | "mul_with_overflow" =>
 307                 (1, vec![param(0), param(0)],
 308                 tcx.intern_tup(&[param(0), tcx.types.bool])),
 309
 310             "unchecked_div" | "unchecked_rem" | "exact_div" =>
 311                 (1, vec![param(0), param(0)], param(0)),
 312             "unchecked_shl" | "unchecked_shr" |
 313             "rotate_left" | "rotate_right" =>
 314                 (1, vec![param(0), param(0)], param(0)),
 315             "unchecked_add" | "unchecked_sub" | "unchecked_mul" =>
 316                 (1, vec![param(0), param(0)], param(0)),
 317             "wrapping_add" | "wrapping_sub" | "wrapping_mul" =>
 318                 (1, vec![param(0), param(0)], param(0)),
 319             "saturating_add" | "saturating_sub" =>
 320                 (1, vec![param(0), param(0)], param(0)),
 321             "fadd_fast" | "fsub_fast" | "fmul_fast" | "fdiv_fast" | "frem_fast" =>
 322                 (1, vec![param(0), param(0)], param(0)),
 323
 324             "assume" => (0, vec![tcx.types.bool], tcx.mk_unit()),
 325             "likely" => (0, vec![tcx.types.bool], tcx.types.bool),
 326             "unlikely" => (0, vec![tcx.types.bool], tcx.types.bool),
 327
 328             "discriminant_value" => (1, vec![
 329                     tcx.mk_imm_ref(tcx.mk_region(ty::ReLateBound(ty::INNERMOST,
 330                                                                  ty::BrAnon(0))),
 331                                    param(0))], tcx.types.u64),
 332
 333             "try" => {
 334                 let mut_u8 = tcx.mk_mut_ptr(tcx.types.u8);
 335                 let fn_ty = ty::Binder::bind(tcx.mk_fn_sig(
 336                     iter::once(mut_u8),
 337                     tcx.mk_unit(),
 338                     false,
 339                     hir::Unsafety::Normal,
 340                     Abi::Rust,
 341                 ));
 342                 (0, vec![tcx.mk_fn_ptr(fn_ty), mut_u8, mut_u8], tcx.types.i32)
 343             }
 344
 345             "va_start" | "va_end" => {
 346                 match mk_va_list_ty(hir::MutMutable) {
 347                     Some((va_list_ref_ty, _)) => (0, vec![va_list_ref_ty], tcx.mk_unit()),
 348                     None => bug!("`va_list` language item needed for C-variadic intrinsics")
 349                 }
 350             }
 351
 352             "va_copy" => {
 353                 match mk_va_list_ty(hir::MutImmutable) {
 354                     Some((va_list_ref_ty, va_list_ty)) => {
 355                         let va_list_ptr_ty = tcx.mk_mut_ptr(va_list_ty);
 356                         (0, vec![va_list_ptr_ty, va_list_ref_ty], tcx.mk_unit())
 357                     }
 358                     None => bug!("`va_list` language item needed for C-variadic intrinsics")
 359                 }
 360             }
 361
 362             "va_arg" => {
 363                 match mk_va_list_ty(hir::MutMutable) {
 364                     Some((va_list_ref_ty, _)) => (1, vec![va_list_ref_ty], param(0)),
 365                     None => bug!("`va_list` language item needed for C-variadic intrinsics")
 366                 }
 367             }
 368
 369             "nontemporal_store" => {
 370                 (1, vec![ tcx.mk_mut_ptr(param(0)), param(0) ], tcx.mk_unit())
 371             }
 372
 373             ref other => {
 374                 struct_span_err!(tcx.sess, it.span, E0093,
 375                                  "unrecognized intrinsic function: `{}`",
 376                                  *other)
 377                                  .span_label(it.span, "unrecognized intrinsic")
 378                                  .emit();
 379                 return;
 380             }
 381         };
 382         (n_tps, inputs, output, unsafety)
 383     };
 384     equate_intrinsic_type(tcx, it, n_tps, Abi::RustIntrinsic, unsafety, inputs, output)
 385 }
 386
 387 /// Type-check `extern "platform-intrinsic" { ... }` functions.
 388 pub fn check_platform_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem) {
 389     let param = |n| {
 390         let name = InternedString::intern(&format!("P{}", n));
 391         tcx.mk_ty_param(n, name)
 392     };
 393
 394     let name = it.ident.as_str();
 395
 396     let (n_tps, inputs, output) = match &*name {
 397         "simd_eq" | "simd_ne" | "simd_lt" | "simd_le" | "simd_gt" | "simd_ge" => {
 398             (2, vec![param(0), param(0)], param(1))
 399         }
 400         "simd_add" | "simd_sub" | "simd_mul" | "simd_rem" |
 401         "simd_div" | "simd_shl" | "simd_shr" |
 402         "simd_and" | "simd_or" | "simd_xor" |
 403         "simd_fmin" | "simd_fmax" | "simd_fpow" |
 404         "simd_saturating_add" | "simd_saturating_sub" => {
 405             (1, vec![param(0), param(0)], param(0))
 406         }
 407         "simd_fsqrt" | "simd_fsin" | "simd_fcos" | "simd_fexp" | "simd_fexp2" |
 408         "simd_flog2" | "simd_flog10" | "simd_flog" |
 409         "simd_fabs" | "simd_floor" | "simd_ceil" => {
 410             (1, vec![param(0)], param(0))
 411         }
 412         "simd_fpowi" => {
 413             (1, vec![param(0), tcx.types.i32], param(0))
 414         }
 415         "simd_fma" => {
 416             (1, vec![param(0), param(0), param(0)], param(0))
 417         }
 418         "simd_gather" => {
 419             (3, vec![param(0), param(1), param(2)], param(0))
 420         }
 421         "simd_scatter" => {
 422             (3, vec![param(0), param(1), param(2)], tcx.mk_unit())
 423         }
 424         "simd_insert" => (2, vec![param(0), tcx.types.u32, param(1)], param(0)),
 425         "simd_extract" => (2, vec![param(0), tcx.types.u32], param(1)),
 426         "simd_cast" => (2, vec![param(0)], param(1)),
 427         "simd_bitmask" => (2, vec![param(0)], param(1)),
 428         "simd_select" |
 429         "simd_select_bitmask" => (2, vec![param(0), param(1), param(1)], param(1)),
 430         "simd_reduce_all" | "simd_reduce_any" => (1, vec![param(0)], tcx.types.bool),
 431         "simd_reduce_add_ordered" | "simd_reduce_mul_ordered"
 432             => (2, vec![param(0), param(1)], param(1)),
 433         "simd_reduce_add_unordered" | "simd_reduce_mul_unordered" |
 434         "simd_reduce_and" | "simd_reduce_or"  | "simd_reduce_xor" |
 435         "simd_reduce_min" | "simd_reduce_max" |
 436         "simd_reduce_min_nanless" | "simd_reduce_max_nanless"
 437             => (2, vec![param(0)], param(1)),
 438         name if name.starts_with("simd_shuffle") => {
 439             match name["simd_shuffle".len()..].parse() {
 440                 Ok(n) => {
 441                     let params = vec![param(0), param(0),
 442                                       tcx.mk_array(tcx.types.u32, n)];
 443                     (2, params, param(1))
 444                 }
 445                 Err(_) => {
 446                     span_err!(tcx.sess, it.span, E0439,
 447                               "invalid `simd_shuffle`, needs length: `{}`", name);
 448                     return
 449                 }
 450             }
 451         }
 452         _ => {
 453             let msg = format!("unrecognized platform-specific intrinsic function: `{}`", name);
 454             tcx.sess.span_err(it.span, &msg);
 455             return;
 456         }
 457     };
 458
 459     equate_intrinsic_type(tcx, it, n_tps, Abi::PlatformIntrinsic, hir::Unsafety::Unsafe,
 460                           inputs, output)
 461 }