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 astconv::AstConv;
  15 use intrinsics;
  16 use middle::def_id::DefId;
  17 use middle::subst;
  18 use middle::ty::FnSig;
  19 use middle::ty::{self, Ty};
  20 use middle::ty::fold::TypeFolder;
  21 use {CrateCtxt, require_same_types};
  22
  23 use std::collections::{HashMap};
  24 use syntax::abi;
  25 use syntax::ast;
  26 use syntax::attr::AttrMetaMethods;
  27 use syntax::codemap::Span;
  28 use syntax::parse::token;
  29
  30 use rustc_front::hir;
  31
  32 fn equate_intrinsic_type<'a, 'tcx>(tcx: &ty::ctxt<'tcx>, it: &hir::ForeignItem,
  33                                    n_tps: usize,
  34                                    abi: abi::Abi,
  35                                    inputs: Vec<ty::Ty<'tcx>>,
  36                                    output: ty::FnOutput<'tcx>) {
  37     let fty = tcx.mk_fn(None, tcx.mk_bare_fn(ty::BareFnTy {
  38         unsafety: hir::Unsafety::Unsafe,
  39         abi: abi,
  40         sig: ty::Binder(FnSig {
  41             inputs: inputs,
  42             output: output,
  43             variadic: false,
  44         }),
  45     }));
  46     let i_ty = tcx.lookup_item_type(DefId::local(it.id));
  47     let i_n_tps = i_ty.generics.types.len(subst::FnSpace);
  48     if i_n_tps != n_tps {
  49         span_err!(tcx.sess, it.span, E0094,
  50             "intrinsic has wrong number of type \
  51              parameters: found {}, expected {}",
  52              i_n_tps, n_tps);
  53     } else {
  54         require_same_types(tcx,
  55                            None,
  56                            false,
  57                            it.span,
  58                            i_ty.ty,
  59                            fty,
  60                            || {
  61                 format!("intrinsic has wrong type: expected `{}`",
  62                          fty)
  63             });
  64     }
  65 }
  66
  67 /// Remember to add all intrinsics here, in librustc_trans/trans/intrinsic.rs,
  68 /// and in libcore/intrinsics.rs
  69 pub fn check_intrinsic_type(ccx: &CrateCtxt, it: &hir::ForeignItem) {
  70     fn param<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>, n: u32) -> Ty<'tcx> {
  71         let name = token::intern(&format!("P{}", n));
  72         ccx.tcx.mk_param(subst::FnSpace, n, name)
  73     }
  74
  75     let tcx = ccx.tcx;
  76     let name = it.ident.name.as_str();
  77     let (n_tps, inputs, output) = if name.starts_with("atomic_") {
  78         let split : Vec<&str> = name.split('_').collect();
  79         assert!(split.len() >= 2, "Atomic intrinsic not correct format");
  80
  81         //We only care about the operation here
  82         let (n_tps, inputs, output) = match split[1] {
  83             "cxchg" => (1, vec!(tcx.mk_mut_ptr(param(ccx, 0)),
  84                                 param(ccx, 0),
  85                                 param(ccx, 0)),
  86                         param(ccx, 0)),
  87             "load" => (1, vec!(tcx.mk_imm_ptr(param(ccx, 0))),
  88                        param(ccx, 0)),
  89             "store" => (1, vec!(tcx.mk_mut_ptr(param(ccx, 0)), param(ccx, 0)),
  90                         tcx.mk_nil()),
  91
  92             "xchg" | "xadd" | "xsub" | "and"  | "nand" | "or" | "xor" | "max" |
  93             "min"  | "umax" | "umin" => {
  94                 (1, vec!(tcx.mk_mut_ptr(param(ccx, 0)), param(ccx, 0)),
  95                  param(ccx, 0))
  96             }
  97             "fence" | "singlethreadfence" => {
  98                 (0, Vec::new(), tcx.mk_nil())
  99             }
 100             op => {
 101                 span_err!(tcx.sess, it.span, E0092,
 102                     "unrecognized atomic operation function: `{}`", op);
 103                 return;
 104             }
 105         };
 106         (n_tps, inputs, ty::FnConverging(output))
 107     } else if &name[..] == "abort" || &name[..] == "unreachable" {
 108         (0, Vec::new(), ty::FnDiverging)
 109     } else {
 110         let (n_tps, inputs, output) = match &name[..] {
 111             "breakpoint" => (0, Vec::new(), tcx.mk_nil()),
 112             "size_of" |
 113             "pref_align_of" | "min_align_of" => (1, Vec::new(), ccx.tcx.types.usize),
 114             "size_of_val" |  "min_align_of_val" => {
 115                 (1, vec![
 116                     tcx.mk_imm_ref(tcx.mk_region(ty::ReLateBound(ty::DebruijnIndex::new(1),
 117                                                                   ty::BrAnon(0))),
 118                                     param(ccx, 0))
 119                  ], ccx.tcx.types.usize)
 120             }
 121             "init" | "init_dropped" => (1, Vec::new(), param(ccx, 0)),
 122             "uninit" => (1, Vec::new(), param(ccx, 0)),
 123             "forget" => (1, vec!( param(ccx, 0) ), tcx.mk_nil()),
 124             "transmute" => (2, vec!( param(ccx, 0) ), param(ccx, 1)),
 125             "move_val_init" => {
 126                 (1,
 127                  vec!(
 128                     tcx.mk_mut_ptr(param(ccx, 0)),
 129                     param(ccx, 0)
 130                   ),
 131                tcx.mk_nil())
 132             }
 133             "drop_in_place" => {
 134                 (1, vec![tcx.mk_mut_ptr(param(ccx, 0))], tcx.mk_nil())
 135             }
 136             "needs_drop" => (1, Vec::new(), ccx.tcx.types.bool),
 137
 138             "type_name" => (1, Vec::new(), tcx.mk_static_str()),
 139             "type_id" => (1, Vec::new(), ccx.tcx.types.u64),
 140             "offset" | "arith_offset" => {
 141               (1,
 142                vec!(
 143                   tcx.mk_ptr(ty::TypeAndMut {
 144                       ty: param(ccx, 0),
 145                       mutbl: hir::MutImmutable
 146                   }),
 147                   ccx.tcx.types.isize
 148                ),
 149                tcx.mk_ptr(ty::TypeAndMut {
 150                    ty: param(ccx, 0),
 151                    mutbl: hir::MutImmutable
 152                }))
 153             }
 154             "copy" | "copy_nonoverlapping" => {
 155               (1,
 156                vec!(
 157                   tcx.mk_ptr(ty::TypeAndMut {
 158                       ty: param(ccx, 0),
 159                       mutbl: hir::MutImmutable
 160                   }),
 161                   tcx.mk_ptr(ty::TypeAndMut {
 162                       ty: param(ccx, 0),
 163                       mutbl: hir::MutMutable
 164                   }),
 165                   tcx.types.usize,
 166                ),
 167                tcx.mk_nil())
 168             }
 169             "volatile_copy_memory" | "volatile_copy_nonoverlapping_memory" => {
 170               (1,
 171                vec!(
 172                   tcx.mk_ptr(ty::TypeAndMut {
 173                       ty: param(ccx, 0),
 174                       mutbl: hir::MutMutable
 175                   }),
 176                   tcx.mk_ptr(ty::TypeAndMut {
 177                       ty: param(ccx, 0),
 178                       mutbl: hir::MutImmutable
 179                   }),
 180                   tcx.types.usize,
 181                ),
 182                tcx.mk_nil())
 183             }
 184             "write_bytes" | "volatile_set_memory" => {
 185               (1,
 186                vec!(
 187                   tcx.mk_ptr(ty::TypeAndMut {
 188                       ty: param(ccx, 0),
 189                       mutbl: hir::MutMutable
 190                   }),
 191                   tcx.types.u8,
 192                   tcx.types.usize,
 193                ),
 194                tcx.mk_nil())
 195             }
 196             "sqrtf32" => (0, vec!( tcx.types.f32 ), tcx.types.f32),
 197             "sqrtf64" => (0, vec!( tcx.types.f64 ), tcx.types.f64),
 198             "powif32" => {
 199                (0,
 200                 vec!( tcx.types.f32, tcx.types.i32 ),
 201                 tcx.types.f32)
 202             }
 203             "powif64" => {
 204                (0,
 205                 vec!( tcx.types.f64, tcx.types.i32 ),
 206                 tcx.types.f64)
 207             }
 208             "sinf32" => (0, vec!( tcx.types.f32 ), tcx.types.f32),
 209             "sinf64" => (0, vec!( tcx.types.f64 ), tcx.types.f64),
 210             "cosf32" => (0, vec!( tcx.types.f32 ), tcx.types.f32),
 211             "cosf64" => (0, vec!( tcx.types.f64 ), tcx.types.f64),
 212             "powf32" => {
 213                (0,
 214                 vec!( tcx.types.f32, tcx.types.f32 ),
 215                 tcx.types.f32)
 216             }
 217             "powf64" => {
 218                (0,
 219                 vec!( tcx.types.f64, tcx.types.f64 ),
 220                 tcx.types.f64)
 221             }
 222             "expf32"   => (0, vec!( tcx.types.f32 ), tcx.types.f32),
 223             "expf64"   => (0, vec!( tcx.types.f64 ), tcx.types.f64),
 224             "exp2f32"  => (0, vec!( tcx.types.f32 ), tcx.types.f32),
 225             "exp2f64"  => (0, vec!( tcx.types.f64 ), tcx.types.f64),
 226             "logf32"   => (0, vec!( tcx.types.f32 ), tcx.types.f32),
 227             "logf64"   => (0, vec!( tcx.types.f64 ), tcx.types.f64),
 228             "log10f32" => (0, vec!( tcx.types.f32 ), tcx.types.f32),
 229             "log10f64" => (0, vec!( tcx.types.f64 ), tcx.types.f64),
 230             "log2f32"  => (0, vec!( tcx.types.f32 ), tcx.types.f32),
 231             "log2f64"  => (0, vec!( tcx.types.f64 ), tcx.types.f64),
 232             "fmaf32" => {
 233                 (0,
 234                  vec!( tcx.types.f32, tcx.types.f32, tcx.types.f32 ),
 235                  tcx.types.f32)
 236             }
 237             "fmaf64" => {
 238                 (0,
 239                  vec!( tcx.types.f64, tcx.types.f64, tcx.types.f64 ),
 240                  tcx.types.f64)
 241             }
 242             "fabsf32"      => (0, vec!( tcx.types.f32 ), tcx.types.f32),
 243             "fabsf64"      => (0, vec!( tcx.types.f64 ), tcx.types.f64),
 244             "copysignf32"  => (0, vec!( tcx.types.f32, tcx.types.f32 ), tcx.types.f32),
 245             "copysignf64"  => (0, vec!( tcx.types.f64, tcx.types.f64 ), tcx.types.f64),
 246             "floorf32"     => (0, vec!( tcx.types.f32 ), tcx.types.f32),
 247             "floorf64"     => (0, vec!( tcx.types.f64 ), tcx.types.f64),
 248             "ceilf32"      => (0, vec!( tcx.types.f32 ), tcx.types.f32),
 249             "ceilf64"      => (0, vec!( tcx.types.f64 ), tcx.types.f64),
 250             "truncf32"     => (0, vec!( tcx.types.f32 ), tcx.types.f32),
 251             "truncf64"     => (0, vec!( tcx.types.f64 ), tcx.types.f64),
 252             "rintf32"      => (0, vec!( tcx.types.f32 ), tcx.types.f32),
 253             "rintf64"      => (0, vec!( tcx.types.f64 ), tcx.types.f64),
 254             "nearbyintf32" => (0, vec!( tcx.types.f32 ), tcx.types.f32),
 255             "nearbyintf64" => (0, vec!( tcx.types.f64 ), tcx.types.f64),
 256             "roundf32"     => (0, vec!( tcx.types.f32 ), tcx.types.f32),
 257             "roundf64"     => (0, vec!( tcx.types.f64 ), tcx.types.f64),
 258             "ctpop8"       => (0, vec!( tcx.types.u8  ), tcx.types.u8),
 259             "ctpop16"      => (0, vec!( tcx.types.u16 ), tcx.types.u16),
 260             "ctpop32"      => (0, vec!( tcx.types.u32 ), tcx.types.u32),
 261             "ctpop64"      => (0, vec!( tcx.types.u64 ), tcx.types.u64),
 262             "ctlz8"        => (0, vec!( tcx.types.u8  ), tcx.types.u8),
 263             "ctlz16"       => (0, vec!( tcx.types.u16 ), tcx.types.u16),
 264             "ctlz32"       => (0, vec!( tcx.types.u32 ), tcx.types.u32),
 265             "ctlz64"       => (0, vec!( tcx.types.u64 ), tcx.types.u64),
 266             "cttz8"        => (0, vec!( tcx.types.u8  ), tcx.types.u8),
 267             "cttz16"       => (0, vec!( tcx.types.u16 ), tcx.types.u16),
 268             "cttz32"       => (0, vec!( tcx.types.u32 ), tcx.types.u32),
 269             "cttz64"       => (0, vec!( tcx.types.u64 ), tcx.types.u64),
 270             "bswap16"      => (0, vec!( tcx.types.u16 ), tcx.types.u16),
 271             "bswap32"      => (0, vec!( tcx.types.u32 ), tcx.types.u32),
 272             "bswap64"      => (0, vec!( tcx.types.u64 ), tcx.types.u64),
 273
 274             "volatile_load" =>
 275                 (1, vec!( tcx.mk_imm_ptr(param(ccx, 0)) ), param(ccx, 0)),
 276             "volatile_store" =>
 277                 (1, vec!( tcx.mk_mut_ptr(param(ccx, 0)), param(ccx, 0) ), tcx.mk_nil()),
 278
 279             "i8_add_with_overflow" | "i8_sub_with_overflow" | "i8_mul_with_overflow" =>
 280                 (0, vec!(tcx.types.i8, tcx.types.i8),
 281                 tcx.mk_tup(vec!(tcx.types.i8, tcx.types.bool))),
 282
 283             "i16_add_with_overflow" | "i16_sub_with_overflow" | "i16_mul_with_overflow" =>
 284                 (0, vec!(tcx.types.i16, tcx.types.i16),
 285                 tcx.mk_tup(vec!(tcx.types.i16, tcx.types.bool))),
 286
 287             "i32_add_with_overflow" | "i32_sub_with_overflow" | "i32_mul_with_overflow" =>
 288                 (0, vec!(tcx.types.i32, tcx.types.i32),
 289                 tcx.mk_tup(vec!(tcx.types.i32, tcx.types.bool))),
 290
 291             "i64_add_with_overflow" | "i64_sub_with_overflow" | "i64_mul_with_overflow" =>
 292                 (0, vec!(tcx.types.i64, tcx.types.i64),
 293                 tcx.mk_tup(vec!(tcx.types.i64, tcx.types.bool))),
 294
 295             "u8_add_with_overflow" | "u8_sub_with_overflow" | "u8_mul_with_overflow" =>
 296                 (0, vec!(tcx.types.u8, tcx.types.u8),
 297                 tcx.mk_tup(vec!(tcx.types.u8, tcx.types.bool))),
 298
 299             "u16_add_with_overflow" | "u16_sub_with_overflow" | "u16_mul_with_overflow" =>
 300                 (0, vec!(tcx.types.u16, tcx.types.u16),
 301                 tcx.mk_tup(vec!(tcx.types.u16, tcx.types.bool))),
 302
 303             "u32_add_with_overflow" | "u32_sub_with_overflow" | "u32_mul_with_overflow"=>
 304                 (0, vec!(tcx.types.u32, tcx.types.u32),
 305                 tcx.mk_tup(vec!(tcx.types.u32, tcx.types.bool))),
 306
 307             "u64_add_with_overflow" | "u64_sub_with_overflow"  | "u64_mul_with_overflow" =>
 308                 (0, vec!(tcx.types.u64, tcx.types.u64),
 309                 tcx.mk_tup(vec!(tcx.types.u64, tcx.types.bool))),
 310
 311             "unchecked_udiv" | "unchecked_sdiv" | "unchecked_urem" | "unchecked_srem" =>
 312                 (1, vec![param(ccx, 0), param(ccx, 0)], param(ccx, 0)),
 313
 314             "overflowing_add" | "overflowing_sub" | "overflowing_mul" =>
 315                 (1, vec![param(ccx, 0), param(ccx, 0)], param(ccx, 0)),
 316
 317             "return_address" => (0, vec![], tcx.mk_imm_ptr(tcx.types.u8)),
 318
 319             "assume" => (0, vec![tcx.types.bool], tcx.mk_nil()),
 320
 321             "discriminant_value" => (1, vec![
 322                     tcx.mk_imm_ref(tcx.mk_region(ty::ReLateBound(ty::DebruijnIndex::new(1),
 323                                                                   ty::BrAnon(0))),
 324                                    param(ccx, 0))], tcx.types.u64),
 325
 326             "try" => {
 327                 let mut_u8 = tcx.mk_mut_ptr(tcx.types.u8);
 328                 let fn_ty = ty::BareFnTy {
 329                     unsafety: hir::Unsafety::Normal,
 330                     abi: abi::Rust,
 331                     sig: ty::Binder(FnSig {
 332                         inputs: vec![mut_u8],
 333                         output: ty::FnOutput::FnConverging(tcx.mk_nil()),
 334                         variadic: false,
 335                     }),
 336                 };
 337                 let fn_ty = tcx.mk_bare_fn(fn_ty);
 338                 (0, vec![tcx.mk_fn(None, fn_ty), mut_u8], mut_u8)
 339             }
 340
 341             ref other => {
 342                 span_err!(tcx.sess, it.span, E0093,
 343                           "unrecognized intrinsic function: `{}`", *other);
 344                 return;
 345             }
 346         };
 347         (n_tps, inputs, ty::FnConverging(output))
 348     };
 349     equate_intrinsic_type(
 350         tcx,
 351         it,
 352         n_tps,
 353         abi::RustIntrinsic,
 354         inputs,
 355         output
 356         )
 357 }
 358
 359 /// Type-check `extern "platform-intrinsic" { ... }` functions.
 360 pub fn check_platform_intrinsic_type(ccx: &CrateCtxt,
 361                                      it: &hir::ForeignItem) {
 362     let param = |n| {
 363         let name = token::intern(&format!("P{}", n));
 364         ccx.tcx.mk_param(subst::FnSpace, n, name)
 365     };
 366
 367     let tcx = ccx.tcx;
 368     let i_ty = tcx.lookup_item_type(DefId::local(it.id));
 369     let i_n_tps = i_ty.generics.types.len(subst::FnSpace);
 370     let name = it.ident.name.as_str();
 371
 372     let (n_tps, inputs, output) = match &*name {
 373         "simd_eq" | "simd_ne" | "simd_lt" | "simd_le" | "simd_gt" | "simd_ge" => {
 374             (2, vec![param(0), param(0)], param(1))
 375         }
 376         "simd_add" | "simd_sub" | "simd_mul" |
 377         "simd_div" | "simd_shl" | "simd_shr" |
 378         "simd_and" | "simd_or" | "simd_xor" => {
 379             (1, vec![param(0), param(0)], param(0))
 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         name if name.starts_with("simd_shuffle") => {
 385             match name["simd_shuffle".len()..].parse() {
 386                 Ok(n) => {
 387                     let params = vec![param(0), param(0),
 388                                       tcx.mk_ty(ty::TyArray(tcx.types.u32, n))];
 389                     (2, params, param(1))
 390                 }
 391                 Err(_) => {
 392                     span_err!(tcx.sess, it.span, E0439,
 393                               "invalid `simd_shuffle`, needs length: `{}`", name);
 394                     return
 395                 }
 396             }
 397         }
 398         _ => {
 399             match intrinsics::Intrinsic::find(tcx, &name) {
 400                 Some(intr) => {
 401                     // this function is a platform specific intrinsic
 402                     if i_n_tps != 0 {
 403                         span_err!(tcx.sess, it.span, E0440,
 404                                   "platform-specific intrinsic has wrong number of type \
 405                                    parameters: found {}, expected 0",
 406                                   i_n_tps);
 407                         return
 408                     }
 409
 410                     let mut structural_to_nomimal = HashMap::new();
 411
 412                     let sig = tcx.no_late_bound_regions(i_ty.ty.fn_sig()).unwrap();
 413                     if intr.inputs.len() != sig.inputs.len() {
 414                         span_err!(tcx.sess, it.span, E0444,
 415                                   "platform-specific intrinsic has invalid number of \
 416                                    arguments: found {}, expected {}",
 417                                   intr.inputs.len(), sig.inputs.len());
 418                         return
 419                     }
 420                     let input_pairs = intr.inputs.iter().zip(&sig.inputs);
 421                     for (i, (expected_arg, arg)) in input_pairs.enumerate() {
 422                         match_intrinsic_type_to_type(tcx, &format!("argument {}", i + 1), it.span,
 423                                                      &mut structural_to_nomimal, expected_arg, arg);
 424                     }
 425                     match_intrinsic_type_to_type(tcx, "return value", it.span,
 426                                                  &mut structural_to_nomimal,
 427                                                  &intr.output, sig.output.unwrap());
 428                     return
 429                 }
 430                 None => {
 431                     span_err!(tcx.sess, it.span, E0441,
 432                               "unrecognized platform-specific intrinsic function: `{}`", name);
 433                     return;
 434                 }
 435             }
 436         }
 437     };
 438
 439     equate_intrinsic_type(
 440         tcx,
 441         it,
 442         n_tps,
 443         abi::PlatformIntrinsic,
 444         inputs,
 445         ty::FnConverging(output)
 446         )
 447 }
 448
 449 // walk the expected type and the actual type in lock step, checking they're
 450 // the same, in a kinda-structural way, i.e. `Vector`s have to be simd structs with
 451 // exactly the right element type
 452 fn match_intrinsic_type_to_type<'tcx, 'a>(
 453         tcx: &ty::ctxt<'tcx>,
 454         position: &str,
 455         span: Span,
 456         structural_to_nominal: &mut HashMap<&'a intrinsics::Type, ty::Ty<'tcx>>,
 457         expected: &'a intrinsics::Type, t: ty::Ty<'tcx>)
 458 {
 459     use intrinsics::Type::*;
 460
 461     let simple_error = |real: &str, expected: &str| {
 462         span_err!(tcx.sess, span, E0442,
 463                   "intrinsic {} has wrong type: found {}, expected {}",
 464                   position, real, expected)
 465     };
 466
 467     match *expected {
 468         Void => match t.sty {
 469             ty::TyTuple(ref v) if v.is_empty() => {},
 470             _ => simple_error(&format!("`{}`", t), "()"),
 471         },
 472         // (The width we pass to LLVM doesn't concern the type checker.)
 473         Integer(signed, bits, _llvm_width) => match (signed, bits, &t.sty) {
 474             (true,  8,  &ty::TyInt(ast::IntTy::TyI8)) |
 475             (false, 8,  &ty::TyUint(ast::UintTy::TyU8)) |
 476             (true,  16, &ty::TyInt(ast::IntTy::TyI16)) |
 477             (false, 16, &ty::TyUint(ast::UintTy::TyU16)) |
 478             (true,  32, &ty::TyInt(ast::IntTy::TyI32)) |
 479             (false, 32, &ty::TyUint(ast::UintTy::TyU32)) |
 480             (true,  64, &ty::TyInt(ast::IntTy::TyI64)) |
 481             (false, 64, &ty::TyUint(ast::UintTy::TyU64)) => {},
 482             _ => simple_error(&format!("`{}`", t),
 483                               &format!("`{}{n}`",
 484                                        if signed {"i"} else {"u"},
 485                                        n = bits)),
 486         },
 487         Float(bits) => match (bits, &t.sty) {
 488             (32, &ty::TyFloat(ast::FloatTy::TyF32)) |
 489             (64, &ty::TyFloat(ast::FloatTy::TyF64)) => {},
 490             _ => simple_error(&format!("`{}`", t),
 491                               &format!("`f{n}`", n = bits)),
 492         },
 493         Pointer(ref inner_expected, ref _llvm_type, const_) => {
 494             match t.sty {
 495                 ty::TyRawPtr(ty::TypeAndMut { ty, mutbl }) => {
 496                     if (mutbl == hir::MutImmutable) != const_ {
 497                         simple_error(&format!("`{}`", t),
 498                                      if const_ {"const pointer"} else {"mut pointer"})
 499                     }
 500                     match_intrinsic_type_to_type(tcx, position, span, structural_to_nominal,
 501                                                  inner_expected, ty)
 502                 }
 503                 _ => simple_error(&format!("`{}`", t),
 504                                   &format!("raw pointer")),
 505             }
 506         }
 507         Vector(ref inner_expected, ref _llvm_type, len) => {
 508             if !t.is_simd() {
 509                 simple_error(&format!("non-simd type `{}`", t),
 510                              "simd type");
 511                 return;
 512             }
 513             let t_len = t.simd_size(tcx);
 514             if len as usize != t_len {
 515                 simple_error(&format!("vector with length {}", t_len),
 516                              &format!("length {}", len));
 517                 return;
 518             }
 519             let t_ty = t.simd_type(tcx);
 520             {
 521                 // check that a given structural type always has the same an intrinsic definition
 522                 let previous = structural_to_nominal.entry(expected).or_insert(t);
 523                 if *previous != t {
 524                     // this gets its own error code because it is non-trivial
 525                     span_err!(tcx.sess, span, E0443,
 526                               "intrinsic {} has wrong type: found `{}`, expected `{}` which \
 527                                was used for this vector type previously in this signature",
 528                               position,
 529                               t,
 530                               *previous);
 531                     return;
 532                 }
 533             }
 534             match_intrinsic_type_to_type(tcx,
 535                                          position,
 536                                          span,
 537                                          structural_to_nominal,
 538                                          inner_expected,
 539                                          t_ty)
 540         }
 541         Aggregate(_flatten, ref expected_contents) => {
 542             match t.sty {
 543                 ty::TyTuple(ref contents) => {
 544                     if contents.len() != expected_contents.len() {
 545                         simple_error(&format!("tuple with length {}", contents.len()),
 546                                      &format!("tuple with length {}", expected_contents.len()));
 547                         return
 548                     }
 549                     for (e, c) in expected_contents.iter().zip(contents) {
 550                         match_intrinsic_type_to_type(tcx, position, span, structural_to_nominal,
 551                                                      e, c)
 552                     }
 553                 }
 554                 _ => simple_error(&format!("`{}`", t),
 555                                   &format!("tuple")),
 556             }
 557         }
 558     }
 559 }