src/librustc_typeck/check/intrinsic.rs

   1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 //! Type-checking for the rust-intrinsic and platform-intrinsic
  12 //! intrinsics that the compiler exposes.
  13
  14 use intrinsics;
  15 use rustc::traits::{ObligationCause, ObligationCauseCode};
  16 use rustc::ty::{self, TyCtxt, Ty};
  17 use rustc::util::nodemap::FxHashMap;
  18 use require_same_types;
  19
  20 use syntax::abi::Abi;
  21 use syntax::ast;
  22 use syntax::symbol::Symbol;
  23 use syntax_pos::Span;
  24
  25 use rustc::hir;
  26
  27 use std::iter;
  28
  29 fn equate_intrinsic_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
  30                                    it: &hir::ForeignItem,
  31                                    n_tps: usize,
  32                                    abi: Abi,
  33                                    inputs: Vec<Ty<'tcx>>,
  34                                    output: Ty<'tcx>) {
  35     let def_id = tcx.hir.local_def_id(it.id);
  36
  37     match it.node {
  38         hir::ForeignItemFn(..) => {}
  39         _ => {
  40             struct_span_err!(tcx.sess, it.span, E0622,
  41                              "intrinsic must be a function")
  42                 .span_label(it.span, "expected a function")
  43                 .emit();
  44             return;
  45         }
  46     }
  47
  48     let i_n_tps = tcx.generics_of(def_id).types.len();
  49     if i_n_tps != n_tps {
  50         let span = match it.node {
  51             hir::ForeignItemFn(_, _, ref generics) => generics.span,
  52             _ => bug!()
  53         };
  54
  55         struct_span_err!(tcx.sess, span, E0094,
  56                         "intrinsic has wrong number of type \
  57                         parameters: found {}, expected {}",
  58                         i_n_tps, n_tps)
  59             .span_label(span, format!("expected {} type parameter", n_tps))
  60             .emit();
  61         return;
  62     }
  63
  64     let fty = tcx.mk_fn_ptr(ty::Binder(tcx.mk_fn_sig(
  65         inputs.into_iter(),
  66         output,
  67         false,
  68         hir::Unsafety::Unsafe,
  69         abi
  70     )));
  71     let cause = ObligationCause::new(it.span, it.id, ObligationCauseCode::IntrinsicType);
  72     require_same_types(tcx, &cause, tcx.mk_fn_ptr(tcx.fn_sig(def_id)), fty);
  73 }
  74
  75 /// Remember to add all intrinsics here, in librustc_trans/trans/intrinsic.rs,
  76 /// and in libcore/intrinsics.rs
  77 pub fn check_intrinsic_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
  78                                       it: &hir::ForeignItem) {
  79     let param = |n| tcx.mk_param(n, Symbol::intern(&format!("P{}", n)));
  80     let name = it.name.as_str();
  81     let (n_tps, inputs, output) = if name.starts_with("atomic_") {
  82         let split : Vec<&str> = name.split('_').collect();
  83         assert!(split.len() >= 2, "Atomic intrinsic not correct format");
  84
  85         //We only care about the operation here
  86         let (n_tps, inputs, output) = match split[1] {
  87             "cxchg" | "cxchgweak" => (1, vec![tcx.mk_mut_ptr(param(0)),
  88                                               param(0),
  89                                               param(0)],
  90                                       tcx.intern_tup(&[param(0), tcx.types.bool], false)),
  91             "load" => (1, vec![tcx.mk_imm_ptr(param(0))],
  92                        param(0)),
  93             "store" => (1, vec![tcx.mk_mut_ptr(param(0)), param(0)],
  94                         tcx.mk_nil()),
  95
  96             "xchg" | "xadd" | "xsub" | "and"  | "nand" | "or" | "xor" | "max" |
  97             "min"  | "umax" | "umin" => {
  98                 (1, vec![tcx.mk_mut_ptr(param(0)), param(0)],
  99                  param(0))
 100             }
 101             "fence" | "singlethreadfence" => {
 102                 (0, Vec::new(), tcx.mk_nil())
 103             }
 104             op => {
 105                 struct_span_err!(tcx.sess, it.span, E0092,
 106                       "unrecognized atomic operation function: `{}`", op)
 107                   .span_label(it.span, "unrecognized atomic operation")
 108                   .emit();
 109                 return;
 110             }
 111         };
 112         (n_tps, inputs, output)
 113     } else if &name[..] == "abort" || &name[..] == "unreachable" {
 114         (0, Vec::new(), tcx.types.never)
 115     } else {
 116         let (n_tps, inputs, output) = match &name[..] {
 117             "breakpoint" => (0, Vec::new(), tcx.mk_nil()),
 118             "size_of" |
 119             "pref_align_of" | "min_align_of" => (1, Vec::new(), tcx.types.usize),
 120             "size_of_val" |  "min_align_of_val" => {
 121                 (1, vec![
 122                     tcx.mk_imm_ref(tcx.mk_region(ty::ReLateBound(ty::DebruijnIndex::new(1),
 123                                                                   ty::BrAnon(0))),
 124                                     param(0))
 125                  ], tcx.types.usize)
 126             }
 127             "rustc_peek" => (1, vec![param(0)], param(0)),
 128             "init" => (1, Vec::new(), param(0)),
 129             "uninit" => (1, Vec::new(), param(0)),
 130             "transmute" => (2, vec![ param(0) ], param(1)),
 131             "move_val_init" => {
 132                 (1,
 133                  vec![
 134                     tcx.mk_mut_ptr(param(0)),
 135                     param(0)
 136                   ],
 137                tcx.mk_nil())
 138             }
 139             "prefetch_read_data" | "prefetch_write_data" |
 140             "prefetch_read_instruction" | "prefetch_write_instruction" => {
 141                 (1, vec![tcx.mk_ptr(ty::TypeAndMut {
 142                           ty: param(0),
 143                           mutbl: hir::MutImmutable
 144                          }), tcx.types.i32],
 145                     tcx.mk_nil())
 146             }
 147             "drop_in_place" => {
 148                 (1, vec![tcx.mk_mut_ptr(param(0))], tcx.mk_nil())
 149             }
 150             "needs_drop" => (1, Vec::new(), tcx.types.bool),
 151
 152             "type_name" => (1, Vec::new(), tcx.mk_static_str()),
 153             "type_id" => (1, Vec::new(), tcx.types.u64),
 154             "offset" | "arith_offset" => {
 155               (1,
 156                vec![
 157                   tcx.mk_ptr(ty::TypeAndMut {
 158                       ty: param(0),
 159                       mutbl: hir::MutImmutable
 160                   }),
 161                   tcx.types.isize
 162                ],
 163                tcx.mk_ptr(ty::TypeAndMut {
 164                    ty: param(0),
 165                    mutbl: hir::MutImmutable
 166                }))
 167             }
 168             "copy" | "copy_nonoverlapping" => {
 169               (1,
 170                vec![
 171                   tcx.mk_ptr(ty::TypeAndMut {
 172                       ty: param(0),
 173                       mutbl: hir::MutImmutable
 174                   }),
 175                   tcx.mk_ptr(ty::TypeAndMut {
 176                       ty: param(0),
 177                       mutbl: hir::MutMutable
 178                   }),
 179                   tcx.types.usize,
 180                ],
 181                tcx.mk_nil())
 182             }
 183             "volatile_copy_memory" | "volatile_copy_nonoverlapping_memory" => {
 184               (1,
 185                vec![
 186                   tcx.mk_ptr(ty::TypeAndMut {
 187                       ty: param(0),
 188                       mutbl: hir::MutMutable
 189                   }),
 190                   tcx.mk_ptr(ty::TypeAndMut {
 191                       ty: param(0),
 192                       mutbl: hir::MutImmutable
 193                   }),
 194                   tcx.types.usize,
 195                ],
 196                tcx.mk_nil())
 197             }
 198             "write_bytes" | "volatile_set_memory" => {
 199               (1,
 200                vec![
 201                   tcx.mk_ptr(ty::TypeAndMut {
 202                       ty: param(0),
 203                       mutbl: hir::MutMutable
 204                   }),
 205                   tcx.types.u8,
 206                   tcx.types.usize,
 207                ],
 208                tcx.mk_nil())
 209             }
 210             "sqrtf32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 211             "sqrtf64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 212             "powif32" => {
 213                (0,
 214                 vec![ tcx.types.f32, tcx.types.i32 ],
 215                 tcx.types.f32)
 216             }
 217             "powif64" => {
 218                (0,
 219                 vec![ tcx.types.f64, tcx.types.i32 ],
 220                 tcx.types.f64)
 221             }
 222             "sinf32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 223             "sinf64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 224             "cosf32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 225             "cosf64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 226             "powf32" => {
 227                (0,
 228                 vec![ tcx.types.f32, tcx.types.f32 ],
 229                 tcx.types.f32)
 230             }
 231             "powf64" => {
 232                (0,
 233                 vec![ tcx.types.f64, tcx.types.f64 ],
 234                 tcx.types.f64)
 235             }
 236             "expf32"   => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 237             "expf64"   => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 238             "exp2f32"  => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 239             "exp2f64"  => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 240             "logf32"   => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 241             "logf64"   => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 242             "log10f32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 243             "log10f64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 244             "log2f32"  => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 245             "log2f64"  => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 246             "fmaf32" => {
 247                 (0,
 248                  vec![ tcx.types.f32, tcx.types.f32, tcx.types.f32 ],
 249                  tcx.types.f32)
 250             }
 251             "fmaf64" => {
 252                 (0,
 253                  vec![ tcx.types.f64, tcx.types.f64, tcx.types.f64 ],
 254                  tcx.types.f64)
 255             }
 256             "fabsf32"      => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 257             "fabsf64"      => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 258             "copysignf32"  => (0, vec![ tcx.types.f32, tcx.types.f32 ], tcx.types.f32),
 259             "copysignf64"  => (0, vec![ tcx.types.f64, tcx.types.f64 ], tcx.types.f64),
 260             "floorf32"     => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 261             "floorf64"     => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 262             "ceilf32"      => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 263             "ceilf64"      => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 264             "truncf32"     => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 265             "truncf64"     => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 266             "rintf32"      => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 267             "rintf64"      => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 268             "nearbyintf32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 269             "nearbyintf64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 270             "roundf32"     => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 271             "roundf64"     => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 272
 273             "volatile_load" =>
 274                 (1, vec![ tcx.mk_imm_ptr(param(0)) ], param(0)),
 275             "volatile_store" =>
 276                 (1, vec![ tcx.mk_mut_ptr(param(0)), param(0) ], tcx.mk_nil()),
 277
 278             "ctpop" | "ctlz" | "ctlz_nonzero" | "cttz" | "cttz_nonzero" | "bswap" =>
 279                 (1, vec![param(0)], param(0)),
 280
 281             "add_with_overflow" | "sub_with_overflow"  | "mul_with_overflow" =>
 282                 (1, vec![param(0), param(0)],
 283                 tcx.intern_tup(&[param(0), tcx.types.bool], false)),
 284
 285             "unchecked_div" | "unchecked_rem" =>
 286                 (1, vec![param(0), param(0)], param(0)),
 287             "unchecked_shl" | "unchecked_shr" =>
 288                 (1, vec![param(0), param(0)], param(0)),
 289
 290             "overflowing_add" | "overflowing_sub" | "overflowing_mul" =>
 291                 (1, vec![param(0), param(0)], param(0)),
 292             "fadd_fast" | "fsub_fast" | "fmul_fast" | "fdiv_fast" | "frem_fast" =>
 293                 (1, vec![param(0), param(0)], param(0)),
 294
 295             "assume" => (0, vec![tcx.types.bool], tcx.mk_nil()),
 296             "likely" => (0, vec![tcx.types.bool], tcx.types.bool),
 297             "unlikely" => (0, vec![tcx.types.bool], tcx.types.bool),
 298
 299             "discriminant_value" => (1, vec![
 300                     tcx.mk_imm_ref(tcx.mk_region(ty::ReLateBound(ty::DebruijnIndex::new(1),
 301                                                                   ty::BrAnon(0))),
 302                                    param(0))], tcx.types.u64),
 303
 304             "try" => {
 305                 let mut_u8 = tcx.mk_mut_ptr(tcx.types.u8);
 306                 let fn_ty = ty::Binder(tcx.mk_fn_sig(
 307                     iter::once(mut_u8),
 308                     tcx.mk_nil(),
 309                     false,
 310                     hir::Unsafety::Normal,
 311                     Abi::Rust,
 312                 ));
 313                 (0, vec![tcx.mk_fn_ptr(fn_ty), mut_u8, mut_u8], tcx.types.i32)
 314             }
 315
 316             ref other => {
 317                 struct_span_err!(tcx.sess, it.span, E0093,
 318                                 "unrecognized intrinsic function: `{}`",
 319                                 *other)
 320                                 .span_label(it.span, "unrecognized intrinsic")
 321                                 .emit();
 322                 return;
 323             }
 324         };
 325         (n_tps, inputs, output)
 326     };
 327     equate_intrinsic_type(tcx, it, n_tps, Abi::RustIntrinsic, inputs, output)
 328 }
 329
 330 /// Type-check `extern "platform-intrinsic" { ... }` functions.
 331 pub fn check_platform_intrinsic_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 332                                                it: &hir::ForeignItem) {
 333     let param = |n| {
 334         let name = Symbol::intern(&format!("P{}", n));
 335         tcx.mk_param(n, name)
 336     };
 337
 338     let def_id = tcx.hir.local_def_id(it.id);
 339     let i_n_tps = tcx.generics_of(def_id).types.len();
 340     let name = it.name.as_str();
 341
 342     let (n_tps, inputs, output) = match &*name {
 343         "simd_eq" | "simd_ne" | "simd_lt" | "simd_le" | "simd_gt" | "simd_ge" => {
 344             (2, vec![param(0), param(0)], param(1))
 345         }
 346         "simd_add" | "simd_sub" | "simd_mul" |
 347         "simd_div" | "simd_shl" | "simd_shr" |
 348         "simd_and" | "simd_or" | "simd_xor" => {
 349             (1, vec![param(0), param(0)], param(0))
 350         }
 351         "simd_insert" => (2, vec![param(0), tcx.types.u32, param(1)], param(0)),
 352         "simd_extract" => (2, vec![param(0), tcx.types.u32], param(1)),
 353         "simd_cast" => (2, vec![param(0)], param(1)),
 354         name if name.starts_with("simd_shuffle") => {
 355             match name["simd_shuffle".len()..].parse() {
 356                 Ok(n) => {
 357                     let params = vec![param(0), param(0),
 358                                       tcx.mk_ty(ty::TyArray(tcx.types.u32, n))];
 359                     (2, params, param(1))
 360                 }
 361                 Err(_) => {
 362                     span_err!(tcx.sess, it.span, E0439,
 363                               "invalid `simd_shuffle`, needs length: `{}`", name);
 364                     return
 365                 }
 366             }
 367         }
 368         _ => {
 369             match intrinsics::Intrinsic::find(&name) {
 370                 Some(intr) => {
 371                     // this function is a platform specific intrinsic
 372                     if i_n_tps != 0 {
 373                         span_err!(tcx.sess, it.span, E0440,
 374                                   "platform-specific intrinsic has wrong number of type \
 375                                    parameters: found {}, expected 0",
 376                                   i_n_tps);
 377                         return
 378                     }
 379
 380                     let mut structural_to_nomimal = FxHashMap();
 381
 382                     let sig = tcx.fn_sig(def_id);
 383                     let sig = tcx.no_late_bound_regions(&sig).unwrap();
 384                     if intr.inputs.len() != sig.inputs().len() {
 385                         span_err!(tcx.sess, it.span, E0444,
 386                                   "platform-specific intrinsic has invalid number of \
 387                                    arguments: found {}, expected {}",
 388                                   sig.inputs().len(), intr.inputs.len());
 389                         return
 390                     }
 391                     let input_pairs = intr.inputs.iter().zip(sig.inputs());
 392                     for (i, (expected_arg, arg)) in input_pairs.enumerate() {
 393                         match_intrinsic_type_to_type(tcx, &format!("argument {}", i + 1), it.span,
 394                                                      &mut structural_to_nomimal, expected_arg, arg);
 395                     }
 396                     match_intrinsic_type_to_type(tcx, "return value", it.span,
 397                                                  &mut structural_to_nomimal,
 398                                                  &intr.output, sig.output());
 399                     return
 400                 }
 401                 None => {
 402                     span_err!(tcx.sess, it.span, E0441,
 403                               "unrecognized platform-specific intrinsic function: `{}`", name);
 404                     return;
 405                 }
 406             }
 407         }
 408     };
 409
 410     equate_intrinsic_type(tcx, it, n_tps, Abi::PlatformIntrinsic,
 411                           inputs, output)
 412 }
 413
 414 // walk the expected type and the actual type in lock step, checking they're
 415 // the same, in a kinda-structural way, i.e. `Vector`s have to be simd structs with
 416 // exactly the right element type
 417 fn match_intrinsic_type_to_type<'a, 'tcx>(
 418         tcx: TyCtxt<'a, 'tcx, 'tcx>,
 419         position: &str,
 420         span: Span,
 421         structural_to_nominal: &mut FxHashMap<&'a intrinsics::Type, ty::Ty<'tcx>>,
 422         expected: &'a intrinsics::Type, t: ty::Ty<'tcx>)
 423 {
 424     use intrinsics::Type::*;
 425
 426     let simple_error = |real: &str, expected: &str| {
 427         span_err!(tcx.sess, span, E0442,
 428                   "intrinsic {} has wrong type: found {}, expected {}",
 429                   position, real, expected)
 430     };
 431
 432     match *expected {
 433         Void => match t.sty {
 434             ty::TyTuple(ref v, _) if v.is_empty() => {},
 435             _ => simple_error(&format!("`{}`", t), "()"),
 436         },
 437         // (The width we pass to LLVM doesn't concern the type checker.)
 438         Integer(signed, bits, _llvm_width) => match (signed, bits, &t.sty) {
 439             (true,  8,  &ty::TyInt(ast::IntTy::I8)) |
 440             (false, 8,  &ty::TyUint(ast::UintTy::U8)) |
 441             (true,  16, &ty::TyInt(ast::IntTy::I16)) |
 442             (false, 16, &ty::TyUint(ast::UintTy::U16)) |
 443             (true,  32, &ty::TyInt(ast::IntTy::I32)) |
 444             (false, 32, &ty::TyUint(ast::UintTy::U32)) |
 445             (true,  64, &ty::TyInt(ast::IntTy::I64)) |
 446             (false, 64, &ty::TyUint(ast::UintTy::U64)) |
 447             (true,  128, &ty::TyInt(ast::IntTy::I128)) |
 448             (false, 128, &ty::TyUint(ast::UintTy::U128)) => {},
 449             _ => simple_error(&format!("`{}`", t),
 450                               &format!("`{}{n}`",
 451                                        if signed {"i"} else {"u"},
 452                                        n = bits)),
 453         },
 454         Float(bits) => match (bits, &t.sty) {
 455             (32, &ty::TyFloat(ast::FloatTy::F32)) |
 456             (64, &ty::TyFloat(ast::FloatTy::F64)) => {},
 457             _ => simple_error(&format!("`{}`", t),
 458                               &format!("`f{n}`", n = bits)),
 459         },
 460         Pointer(ref inner_expected, ref _llvm_type, const_) => {
 461             match t.sty {
 462                 ty::TyRawPtr(ty::TypeAndMut { ty, mutbl }) => {
 463                     if (mutbl == hir::MutImmutable) != const_ {
 464                         simple_error(&format!("`{}`", t),
 465                                      if const_ {"const pointer"} else {"mut pointer"})
 466                     }
 467                     match_intrinsic_type_to_type(tcx, position, span, structural_to_nominal,
 468                                                  inner_expected, ty)
 469                 }
 470                 _ => simple_error(&format!("`{}`", t), "raw pointer"),
 471             }
 472         }
 473         Vector(ref inner_expected, ref _llvm_type, len) => {
 474             if !t.is_simd() {
 475                 simple_error(&format!("non-simd type `{}`", t), "simd type");
 476                 return;
 477             }
 478             let t_len = t.simd_size(tcx);
 479             if len as usize != t_len {
 480                 simple_error(&format!("vector with length {}", t_len),
 481                              &format!("length {}", len));
 482                 return;
 483             }
 484             let t_ty = t.simd_type(tcx);
 485             {
 486                 // check that a given structural type always has the same an intrinsic definition
 487                 let previous = structural_to_nominal.entry(expected).or_insert(t);
 488                 if *previous != t {
 489                     // this gets its own error code because it is non-trivial
 490                     span_err!(tcx.sess, span, E0443,
 491                               "intrinsic {} has wrong type: found `{}`, expected `{}` which \
 492                                was used for this vector type previously in this signature",
 493                               position,
 494                               t,
 495                               *previous);
 496                     return;
 497                 }
 498             }
 499             match_intrinsic_type_to_type(tcx,
 500                                          position,
 501                                          span,
 502                                          structural_to_nominal,
 503                                          inner_expected,
 504                                          t_ty)
 505         }
 506         Aggregate(_flatten, ref expected_contents) => {
 507             match t.sty {
 508                 ty::TyTuple(contents, _) => {
 509                     if contents.len() != expected_contents.len() {
 510                         simple_error(&format!("tuple with length {}", contents.len()),
 511                                      &format!("tuple with length {}", expected_contents.len()));
 512                         return
 513                     }
 514                     for (e, c) in expected_contents.iter().zip(contents) {
 515                         match_intrinsic_type_to_type(tcx, position, span, structural_to_nominal,
 516                                                      e, c)
 517                     }
 518                 }
 519                 _ => simple_error(&format!("`{}`", t),
 520                                   "tuple"),
 521             }
 522         }
 523     }
 524 }