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 rustc_target::spec::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>(
  30     tcx: TyCtxt<'a, 'tcx, 'tcx>,
  31     it: &hir::ForeignItem,
  32     n_tps: usize,
  33     abi: Abi,
  34     safety: hir::Unsafety,
  35     inputs: Vec<Ty<'tcx>>,
  36     output: Ty<'tcx>,
  37 ) {
  38     let def_id = tcx.hir.local_def_id(it.id);
  39
  40     match it.node {
  41         hir::ForeignItemKind::Fn(..) => {}
  42         _ => {
  43             struct_span_err!(tcx.sess, it.span, E0622,
  44                              "intrinsic must be a function")
  45                 .span_label(it.span, "expected a function")
  46                 .emit();
  47             return;
  48         }
  49     }
  50
  51     let i_n_tps = tcx.generics_of(def_id).own_counts().types;
  52     if i_n_tps != n_tps {
  53         let span = match it.node {
  54             hir::ForeignItemKind::Fn(_, _, ref generics) => generics.span,
  55             _ => bug!()
  56         };
  57
  58         struct_span_err!(tcx.sess, span, E0094,
  59                         "intrinsic has wrong number of type \
  60                          parameters: found {}, expected {}",
  61                         i_n_tps, n_tps)
  62             .span_label(span, format!("expected {} type parameter", n_tps))
  63             .emit();
  64         return;
  65     }
  66
  67     let fty = tcx.mk_fn_ptr(ty::Binder::bind(tcx.mk_fn_sig(
  68         inputs.into_iter(),
  69         output,
  70         false,
  71         safety,
  72         abi
  73     )));
  74     let cause = ObligationCause::new(it.span, it.id, ObligationCauseCode::IntrinsicType);
  75     require_same_types(tcx, &cause, tcx.mk_fn_ptr(tcx.fn_sig(def_id)), fty);
  76 }
  77
  78 /// Remember to add all intrinsics here, in librustc_codegen_llvm/intrinsic.rs,
  79 /// and in libcore/intrinsics.rs
  80 pub fn check_intrinsic_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
  81                                       it: &hir::ForeignItem) {
  82     let param = |n| tcx.mk_ty_param(n, Symbol::intern(&format!("P{}", n)).as_interned_str());
  83     let name = it.name.as_str();
  84     let (n_tps, inputs, output, unsafety) = if name.starts_with("atomic_") {
  85         let split : Vec<&str> = name.split('_').collect();
  86         assert!(split.len() >= 2, "Atomic intrinsic in an incorrect format");
  87
  88         //We only care about the operation here
  89         let (n_tps, inputs, output) = match split[1] {
  90             "cxchg" | "cxchgweak" => (1, vec![tcx.mk_mut_ptr(param(0)),
  91                                               param(0),
  92                                               param(0)],
  93                                       tcx.intern_tup(&[param(0), tcx.types.bool])),
  94             "load" => (1, vec![tcx.mk_imm_ptr(param(0))],
  95                        param(0)),
  96             "store" => (1, vec![tcx.mk_mut_ptr(param(0)), param(0)],
  97                         tcx.mk_unit()),
  98
  99             "xchg" | "xadd" | "xsub" | "and"  | "nand" | "or" | "xor" | "max" |
 100             "min"  | "umax" | "umin" => {
 101                 (1, vec![tcx.mk_mut_ptr(param(0)), param(0)],
 102                  param(0))
 103             }
 104             "fence" | "singlethreadfence" => {
 105                 (0, Vec::new(), tcx.mk_unit())
 106             }
 107             op => {
 108                 struct_span_err!(tcx.sess, it.span, E0092,
 109                       "unrecognized atomic operation function: `{}`", op)
 110                   .span_label(it.span, "unrecognized atomic operation")
 111                   .emit();
 112                 return;
 113             }
 114         };
 115         (n_tps, inputs, output, hir::Unsafety::Unsafe)
 116     } else if &name[..] == "abort" || &name[..] == "unreachable" {
 117         (0, Vec::new(), tcx.types.never, hir::Unsafety::Unsafe)
 118     } else {
 119         let unsafety = match &name[..] {
 120             "size_of" | "min_align_of" | "needs_drop" => hir::Unsafety::Normal,
 121             _ => hir::Unsafety::Unsafe,
 122         };
 123         let (n_tps, inputs, output) = match &name[..] {
 124             "breakpoint" => (0, Vec::new(), tcx.mk_unit()),
 125             "size_of" |
 126             "pref_align_of" | "min_align_of" => (1, Vec::new(), tcx.types.usize),
 127             "size_of_val" |  "min_align_of_val" => {
 128                 (1, vec![
 129                     tcx.mk_imm_ref(tcx.mk_region(ty::ReLateBound(ty::INNERMOST,
 130                                                                  ty::BrAnon(0))),
 131                                    param(0))
 132                  ], tcx.types.usize)
 133             }
 134             "rustc_peek" => (1, vec![param(0)], param(0)),
 135             "init" => (1, Vec::new(), param(0)),
 136             "uninit" => (1, Vec::new(), param(0)),
 137             "transmute" => (2, vec![ param(0) ], param(1)),
 138             "move_val_init" => {
 139                 (1,
 140                  vec![
 141                     tcx.mk_mut_ptr(param(0)),
 142                     param(0)
 143                   ],
 144                tcx.mk_unit())
 145             }
 146             "prefetch_read_data" | "prefetch_write_data" |
 147             "prefetch_read_instruction" | "prefetch_write_instruction" => {
 148                 (1, vec![tcx.mk_ptr(ty::TypeAndMut {
 149                           ty: param(0),
 150                           mutbl: hir::MutImmutable
 151                          }), tcx.types.i32],
 152                     tcx.mk_unit())
 153             }
 154             "drop_in_place" => {
 155                 (1, vec![tcx.mk_mut_ptr(param(0))], tcx.mk_unit())
 156             }
 157             "needs_drop" => (1, Vec::new(), tcx.types.bool),
 158
 159             "type_name" => (1, Vec::new(), tcx.mk_static_str()),
 160             "type_id" => (1, Vec::new(), tcx.types.u64),
 161             "offset" | "arith_offset" => {
 162               (1,
 163                vec![
 164                   tcx.mk_ptr(ty::TypeAndMut {
 165                       ty: param(0),
 166                       mutbl: hir::MutImmutable
 167                   }),
 168                   tcx.types.isize
 169                ],
 170                tcx.mk_ptr(ty::TypeAndMut {
 171                    ty: param(0),
 172                    mutbl: hir::MutImmutable
 173                }))
 174             }
 175             "copy" | "copy_nonoverlapping" => {
 176               (1,
 177                vec![
 178                   tcx.mk_ptr(ty::TypeAndMut {
 179                       ty: param(0),
 180                       mutbl: hir::MutImmutable
 181                   }),
 182                   tcx.mk_ptr(ty::TypeAndMut {
 183                       ty: param(0),
 184                       mutbl: hir::MutMutable
 185                   }),
 186                   tcx.types.usize,
 187                ],
 188                tcx.mk_unit())
 189             }
 190             "volatile_copy_memory" | "volatile_copy_nonoverlapping_memory" => {
 191               (1,
 192                vec![
 193                   tcx.mk_ptr(ty::TypeAndMut {
 194                       ty: param(0),
 195                       mutbl: hir::MutMutable
 196                   }),
 197                   tcx.mk_ptr(ty::TypeAndMut {
 198                       ty: param(0),
 199                       mutbl: hir::MutImmutable
 200                   }),
 201                   tcx.types.usize,
 202                ],
 203                tcx.mk_unit())
 204             }
 205             "write_bytes" | "volatile_set_memory" => {
 206               (1,
 207                vec![
 208                   tcx.mk_ptr(ty::TypeAndMut {
 209                       ty: param(0),
 210                       mutbl: hir::MutMutable
 211                   }),
 212                   tcx.types.u8,
 213                   tcx.types.usize,
 214                ],
 215                tcx.mk_unit())
 216             }
 217             "sqrtf32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 218             "sqrtf64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 219             "powif32" => {
 220                (0,
 221                 vec![ tcx.types.f32, tcx.types.i32 ],
 222                 tcx.types.f32)
 223             }
 224             "powif64" => {
 225                (0,
 226                 vec![ tcx.types.f64, tcx.types.i32 ],
 227                 tcx.types.f64)
 228             }
 229             "sinf32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 230             "sinf64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 231             "cosf32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 232             "cosf64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 233             "powf32" => {
 234                (0,
 235                 vec![ tcx.types.f32, tcx.types.f32 ],
 236                 tcx.types.f32)
 237             }
 238             "powf64" => {
 239                (0,
 240                 vec![ tcx.types.f64, tcx.types.f64 ],
 241                 tcx.types.f64)
 242             }
 243             "expf32"   => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 244             "expf64"   => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 245             "exp2f32"  => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 246             "exp2f64"  => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 247             "logf32"   => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 248             "logf64"   => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 249             "log10f32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 250             "log10f64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 251             "log2f32"  => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 252             "log2f64"  => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 253             "fmaf32" => {
 254                 (0,
 255                  vec![ tcx.types.f32, tcx.types.f32, tcx.types.f32 ],
 256                  tcx.types.f32)
 257             }
 258             "fmaf64" => {
 259                 (0,
 260                  vec![ tcx.types.f64, tcx.types.f64, tcx.types.f64 ],
 261                  tcx.types.f64)
 262             }
 263             "fabsf32"      => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 264             "fabsf64"      => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 265             "copysignf32"  => (0, vec![ tcx.types.f32, tcx.types.f32 ], tcx.types.f32),
 266             "copysignf64"  => (0, vec![ tcx.types.f64, tcx.types.f64 ], tcx.types.f64),
 267             "floorf32"     => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 268             "floorf64"     => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 269             "ceilf32"      => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 270             "ceilf64"      => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 271             "truncf32"     => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 272             "truncf64"     => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 273             "rintf32"      => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 274             "rintf64"      => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 275             "nearbyintf32" => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 276             "nearbyintf64" => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 277             "roundf32"     => (0, vec![ tcx.types.f32 ], tcx.types.f32),
 278             "roundf64"     => (0, vec![ tcx.types.f64 ], tcx.types.f64),
 279
 280             "volatile_load" | "unaligned_volatile_load" =>
 281                 (1, vec![ tcx.mk_imm_ptr(param(0)) ], param(0)),
 282             "volatile_store" | "unaligned_volatile_store" =>
 283                 (1, vec![ tcx.mk_mut_ptr(param(0)), param(0) ], tcx.mk_unit()),
 284
 285             "ctpop" | "ctlz" | "ctlz_nonzero" | "cttz" | "cttz_nonzero" |
 286             "bswap" | "bitreverse" =>
 287                 (1, vec![param(0)], param(0)),
 288
 289             "add_with_overflow" | "sub_with_overflow"  | "mul_with_overflow" =>
 290                 (1, vec![param(0), param(0)],
 291                 tcx.intern_tup(&[param(0), tcx.types.bool])),
 292
 293             "unchecked_div" | "unchecked_rem" | "exact_div" =>
 294                 (1, vec![param(0), param(0)], param(0)),
 295             "unchecked_shl" | "unchecked_shr" =>
 296                 (1, vec![param(0), param(0)], param(0)),
 297
 298             "overflowing_add" | "overflowing_sub" | "overflowing_mul" =>
 299                 (1, vec![param(0), param(0)], param(0)),
 300             "fadd_fast" | "fsub_fast" | "fmul_fast" | "fdiv_fast" | "frem_fast" =>
 301                 (1, vec![param(0), param(0)], param(0)),
 302
 303             "assume" => (0, vec![tcx.types.bool], tcx.mk_unit()),
 304             "likely" => (0, vec![tcx.types.bool], tcx.types.bool),
 305             "unlikely" => (0, vec![tcx.types.bool], tcx.types.bool),
 306
 307             "discriminant_value" => (1, vec![
 308                     tcx.mk_imm_ref(tcx.mk_region(ty::ReLateBound(ty::INNERMOST,
 309                                                                  ty::BrAnon(0))),
 310                                    param(0))], tcx.types.u64),
 311
 312             "try" => {
 313                 let mut_u8 = tcx.mk_mut_ptr(tcx.types.u8);
 314                 let fn_ty = ty::Binder::bind(tcx.mk_fn_sig(
 315                     iter::once(mut_u8),
 316                     tcx.mk_unit(),
 317                     false,
 318                     hir::Unsafety::Normal,
 319                     Abi::Rust,
 320                 ));
 321                 (0, vec![tcx.mk_fn_ptr(fn_ty), mut_u8, mut_u8], tcx.types.i32)
 322             }
 323
 324             "nontemporal_store" => {
 325                 (1, vec![ tcx.mk_mut_ptr(param(0)), param(0) ], tcx.mk_unit())
 326             }
 327
 328             ref other => {
 329                 struct_span_err!(tcx.sess, it.span, E0093,
 330                                  "unrecognized intrinsic function: `{}`",
 331                                  *other)
 332                                  .span_label(it.span, "unrecognized intrinsic")
 333                                  .emit();
 334                 return;
 335             }
 336         };
 337         (n_tps, inputs, output, unsafety)
 338     };
 339     equate_intrinsic_type(tcx, it, n_tps, Abi::RustIntrinsic, unsafety, inputs, output)
 340 }
 341
 342 /// Type-check `extern "platform-intrinsic" { ... }` functions.
 343 pub fn check_platform_intrinsic_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 344                                                it: &hir::ForeignItem) {
 345     let param = |n| {
 346         let name = Symbol::intern(&format!("P{}", n)).as_interned_str();
 347         tcx.mk_ty_param(n, name)
 348     };
 349
 350     let def_id = tcx.hir.local_def_id(it.id);
 351     let i_n_tps = tcx.generics_of(def_id).own_counts().types;
 352     let name = it.name.as_str();
 353
 354     let (n_tps, inputs, output) = match &*name {
 355         "simd_eq" | "simd_ne" | "simd_lt" | "simd_le" | "simd_gt" | "simd_ge" => {
 356             (2, vec![param(0), param(0)], param(1))
 357         }
 358         "simd_add" | "simd_sub" | "simd_mul" | "simd_rem" |
 359         "simd_div" | "simd_shl" | "simd_shr" |
 360         "simd_and" | "simd_or" | "simd_xor" |
 361         "simd_fmin" | "simd_fmax" | "simd_fpow" => {
 362             (1, vec![param(0), param(0)], param(0))
 363         }
 364         "simd_fsqrt" | "simd_fsin" | "simd_fcos" | "simd_fexp" | "simd_fexp2" |
 365         "simd_flog2" | "simd_flog10" | "simd_flog" |
 366         "simd_fabs" | "simd_floor" | "simd_ceil" => {
 367             (1, vec![param(0)], param(0))
 368         }
 369         "simd_fpowi" => {
 370             (1, vec![param(0), tcx.types.i32], param(0))
 371         }
 372         "simd_fma" => {
 373             (1, vec![param(0), param(0), param(0)], param(0))
 374         }
 375         "simd_gather" => {
 376             (3, vec![param(0), param(1), param(2)], param(0))
 377         }
 378         "simd_scatter" => {
 379             (3, vec![param(0), param(1), param(2)], tcx.mk_unit())
 380         }
 381         "simd_insert" => (2, vec![param(0), tcx.types.u32, param(1)], param(0)),
 382         "simd_extract" => (2, vec![param(0), tcx.types.u32], param(1)),
 383         "simd_cast" => (2, vec![param(0)], param(1)),
 384         "simd_select" => (2, vec![param(0), param(1), param(1)], param(1)),
 385         "simd_reduce_all" | "simd_reduce_any" => (1, vec![param(0)], tcx.types.bool),
 386         "simd_reduce_add_ordered" | "simd_reduce_mul_ordered"
 387             => (2, vec![param(0), param(1)], param(1)),
 388         "simd_reduce_add_unordered" | "simd_reduce_mul_unordered" |
 389         "simd_reduce_and" | "simd_reduce_or"  | "simd_reduce_xor" |
 390         "simd_reduce_min" | "simd_reduce_max" |
 391         "simd_reduce_min_nanless" | "simd_reduce_max_nanless"
 392             => (2, vec![param(0)], param(1)),
 393         name if name.starts_with("simd_shuffle") => {
 394             match name["simd_shuffle".len()..].parse() {
 395                 Ok(n) => {
 396                     let params = vec![param(0), param(0),
 397                                       tcx.mk_array(tcx.types.u32, n)];
 398                     (2, params, param(1))
 399                 }
 400                 Err(_) => {
 401                     span_err!(tcx.sess, it.span, E0439,
 402                               "invalid `simd_shuffle`, needs length: `{}`", name);
 403                     return
 404                 }
 405             }
 406         }
 407         _ => {
 408             match intrinsics::Intrinsic::find(&name) {
 409                 Some(intr) => {
 410                     // this function is a platform specific intrinsic
 411                     if i_n_tps != 0 {
 412                         span_err!(tcx.sess, it.span, E0440,
 413                                   "platform-specific intrinsic has wrong number of type \
 414                                    parameters: found {}, expected 0",
 415                                   i_n_tps);
 416                         return
 417                     }
 418
 419                     let mut structural_to_nomimal = FxHashMap::default();
 420
 421                     let sig = tcx.fn_sig(def_id);
 422                     let sig = sig.no_late_bound_regions().unwrap();
 423                     if intr.inputs.len() != sig.inputs().len() {
 424                         span_err!(tcx.sess, it.span, E0444,
 425                                   "platform-specific intrinsic has invalid number of \
 426                                    arguments: found {}, expected {}",
 427                                   sig.inputs().len(), intr.inputs.len());
 428                         return
 429                     }
 430                     let input_pairs = intr.inputs.iter().zip(sig.inputs());
 431                     for (i, (expected_arg, arg)) in input_pairs.enumerate() {
 432                         match_intrinsic_type_to_type(tcx, &format!("argument {}", i + 1), it.span,
 433                                                      &mut structural_to_nomimal, expected_arg, arg);
 434                     }
 435                     match_intrinsic_type_to_type(tcx, "return value", it.span,
 436                                                  &mut structural_to_nomimal,
 437                                                  &intr.output, sig.output());
 438                     return
 439                 }
 440                 None => {
 441                     span_err!(tcx.sess, it.span, E0441,
 442                               "unrecognized platform-specific intrinsic function: `{}`", name);
 443                     return;
 444                 }
 445             }
 446         }
 447     };
 448
 449     equate_intrinsic_type(tcx, it, n_tps, Abi::PlatformIntrinsic, hir::Unsafety::Unsafe,
 450                           inputs, output)
 451 }
 452
 453 // walk the expected type and the actual type in lock step, checking they're
 454 // the same, in a kinda-structural way, i.e. `Vector`s have to be simd structs with
 455 // exactly the right element type
 456 fn match_intrinsic_type_to_type<'a, 'tcx>(
 457         tcx: TyCtxt<'a, 'tcx, 'tcx>,
 458         position: &str,
 459         span: Span,
 460         structural_to_nominal: &mut FxHashMap<&'a intrinsics::Type, Ty<'tcx>>,
 461         expected: &'a intrinsics::Type, t: Ty<'tcx>)
 462 {
 463     use intrinsics::Type::*;
 464
 465     let simple_error = |real: &str, expected: &str| {
 466         span_err!(tcx.sess, span, E0442,
 467                   "intrinsic {} has wrong type: found {}, expected {}",
 468                   position, real, expected)
 469     };
 470
 471     match *expected {
 472         Void => match t.sty {
 473             ty::Tuple(ref v) if v.is_empty() => {},
 474             _ => simple_error(&format!("`{}`", t), "()"),
 475         },
 476         // (The width we pass to LLVM doesn't concern the type checker.)
 477         Integer(signed, bits, _llvm_width) => match (signed, bits, &t.sty) {
 478             (true,  8,  &ty::Int(ast::IntTy::I8)) |
 479             (false, 8,  &ty::Uint(ast::UintTy::U8)) |
 480             (true,  16, &ty::Int(ast::IntTy::I16)) |
 481             (false, 16, &ty::Uint(ast::UintTy::U16)) |
 482             (true,  32, &ty::Int(ast::IntTy::I32)) |
 483             (false, 32, &ty::Uint(ast::UintTy::U32)) |
 484             (true,  64, &ty::Int(ast::IntTy::I64)) |
 485             (false, 64, &ty::Uint(ast::UintTy::U64)) |
 486             (true,  128, &ty::Int(ast::IntTy::I128)) |
 487             (false, 128, &ty::Uint(ast::UintTy::U128)) => {},
 488             _ => simple_error(&format!("`{}`", t),
 489                               &format!("`{}{n}`",
 490                                        if signed {"i"} else {"u"},
 491                                        n = bits)),
 492         },
 493         Float(bits) => match (bits, &t.sty) {
 494             (32, &ty::Float(ast::FloatTy::F32)) |
 495             (64, &ty::Float(ast::FloatTy::F64)) => {},
 496             _ => simple_error(&format!("`{}`", t),
 497                               &format!("`f{n}`", n = bits)),
 498         },
 499         Pointer(ref inner_expected, ref _llvm_type, const_) => {
 500             match t.sty {
 501                 ty::RawPtr(ty::TypeAndMut { ty, mutbl }) => {
 502                     if (mutbl == hir::MutImmutable) != const_ {
 503                         simple_error(&format!("`{}`", t),
 504                                      if const_ {"const pointer"} else {"mut pointer"})
 505                     }
 506                     match_intrinsic_type_to_type(tcx, position, span, structural_to_nominal,
 507                                                  inner_expected, ty)
 508                 }
 509                 _ => simple_error(&format!("`{}`", t), "raw pointer"),
 510             }
 511         }
 512         Vector(ref inner_expected, ref _llvm_type, len) => {
 513             if !t.is_simd() {
 514                 simple_error(&format!("non-simd type `{}`", t), "simd type");
 515                 return;
 516             }
 517             let t_len = t.simd_size(tcx);
 518             if len as usize != t_len {
 519                 simple_error(&format!("vector with length {}", t_len),
 520                              &format!("length {}", len));
 521                 return;
 522             }
 523             let t_ty = t.simd_type(tcx);
 524             {
 525                 // check that a given structural type always has the same an intrinsic definition
 526                 let previous = structural_to_nominal.entry(expected).or_insert(t);
 527                 if *previous != t {
 528                     // this gets its own error code because it is non-trivial
 529                     span_err!(tcx.sess, span, E0443,
 530                               "intrinsic {} has wrong type: found `{}`, expected `{}` which \
 531                                was used for this vector type previously in this signature",
 532                               position,
 533                               t,
 534                               *previous);
 535                     return;
 536                 }
 537             }
 538             match_intrinsic_type_to_type(tcx,
 539                                          position,
 540                                          span,
 541                                          structural_to_nominal,
 542                                          inner_expected,
 543                                          t_ty)
 544         }
 545         Aggregate(_flatten, ref expected_contents) => {
 546             match t.sty {
 547                 ty::Tuple(contents) => {
 548                     if contents.len() != expected_contents.len() {
 549                         simple_error(&format!("tuple with length {}", contents.len()),
 550                                      &format!("tuple with length {}", expected_contents.len()));
 551                         return
 552                     }
 553                     for (e, c) in expected_contents.iter().zip(contents) {
 554                         match_intrinsic_type_to_type(tcx, position, span, structural_to_nominal,
 555                                                      e, c)
 556                     }
 557                 }
 558                 _ => simple_error(&format!("`{}`", t),
 559                                   "tuple"),
 560             }
 561         }
 562     }
 563 }