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Rollup merge of #96033 - yaahc:expect-elaboration, r=scottmcm
[rust.git] / compiler / rustc_typeck / src / check / intrinsic.rs
1 //! Type-checking for the rust-intrinsic and platform-intrinsic
2 //! intrinsics that the compiler exposes.
3
4 use crate::errors::{
5     UnrecognizedAtomicOperation, UnrecognizedIntrinsicFunction,
6     WrongNumberOfGenericArgumentsToIntrinsic,
7 };
8 use crate::require_same_types;
9
10 use rustc_errors::struct_span_err;
11 use rustc_hir as hir;
12 use rustc_middle::traits::{ObligationCause, ObligationCauseCode};
13 use rustc_middle::ty::subst::Subst;
14 use rustc_middle::ty::{self, TyCtxt};
15 use rustc_span::symbol::{kw, sym, Symbol};
16 use rustc_target::spec::abi::Abi;
17
18 use std::iter;
19
20 fn equate_intrinsic_type<'tcx>(
21     tcx: TyCtxt<'tcx>,
22     it: &hir::ForeignItem<'_>,
23     n_tps: usize,
24     n_lts: usize,
25     sig: ty::PolyFnSig<'tcx>,
26 ) {
27     let (own_counts, span) = match &it.kind {
28         hir::ForeignItemKind::Fn(.., generics) => {
29             let own_counts = tcx.generics_of(it.def_id.to_def_id()).own_counts();
30             (own_counts, generics.span)
31         }
32         _ => {
33             struct_span_err!(tcx.sess, it.span, E0622, "intrinsic must be a function")
34                 .span_label(it.span, "expected a function")
35                 .emit();
36             return;
37         }
38     };
39
40     let gen_count_ok = |found: usize, expected: usize, descr: &str| -> bool {
41         if found != expected {
42             tcx.sess.emit_err(WrongNumberOfGenericArgumentsToIntrinsic {
43                 span,
44                 found,
45                 expected,
46                 descr,
47             });
48             false
49         } else {
50             true
51         }
52     };
53
54     if gen_count_ok(own_counts.lifetimes, n_lts, "lifetime")
55         && gen_count_ok(own_counts.types, n_tps, "type")
56         && gen_count_ok(own_counts.consts, 0, "const")
57     {
58         let fty = tcx.mk_fn_ptr(sig);
59         let cause = ObligationCause::new(it.span, it.hir_id(), ObligationCauseCode::IntrinsicType);
60         require_same_types(tcx, &cause, tcx.mk_fn_ptr(tcx.fn_sig(it.def_id)), fty);
61     }
62 }
63
64 /// Returns the unsafety of the given intrinsic.
65 pub fn intrinsic_operation_unsafety(intrinsic: Symbol) -> hir::Unsafety {
66     match intrinsic {
67         // When adding a new intrinsic to this list,
68         // it's usually worth updating that intrinsic's documentation
69         // to note that it's safe to call, since
70         // safe extern fns are otherwise unprecedented.
71         sym::abort
72         | sym::size_of
73         | sym::min_align_of
74         | sym::needs_drop
75         | sym::caller_location
76         | sym::add_with_overflow
77         | sym::sub_with_overflow
78         | sym::mul_with_overflow
79         | sym::wrapping_add
80         | sym::wrapping_sub
81         | sym::wrapping_mul
82         | sym::saturating_add
83         | sym::saturating_sub
84         | sym::rotate_left
85         | sym::rotate_right
86         | sym::ctpop
87         | sym::ctlz
88         | sym::cttz
89         | sym::bswap
90         | sym::bitreverse
91         | sym::discriminant_value
92         | sym::type_id
93         | sym::likely
94         | sym::unlikely
95         | sym::ptr_guaranteed_eq
96         | sym::ptr_guaranteed_ne
97         | sym::minnumf32
98         | sym::minnumf64
99         | sym::maxnumf32
100         | sym::rustc_peek
101         | sym::maxnumf64
102         | sym::type_name
103         | sym::forget
104         | sym::black_box
105         | sym::variant_count => hir::Unsafety::Normal,
106         _ => hir::Unsafety::Unsafe,
107     }
108 }
109
110 /// Remember to add all intrinsics here, in `compiler/rustc_codegen_llvm/src/intrinsic.rs`,
111 /// and in `library/core/src/intrinsics.rs`.
112 pub fn check_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>) {
113     let param = |n| tcx.mk_ty_param(n, Symbol::intern(&format!("P{}", n)));
114     let intrinsic_name = tcx.item_name(it.def_id.to_def_id());
115     let name_str = intrinsic_name.as_str();
116
117     let bound_vars = tcx.mk_bound_variable_kinds(
118         [ty::BoundVariableKind::Region(ty::BrAnon(0)), ty::BoundVariableKind::Region(ty::BrEnv)]
119             .iter()
120             .copied(),
121     );
122     let mk_va_list_ty = |mutbl| {
123         tcx.lang_items().va_list().map(|did| {
124             let region = tcx.mk_region(ty::ReLateBound(
125                 ty::INNERMOST,
126                 ty::BoundRegion { var: ty::BoundVar::from_u32(0), kind: ty::BrAnon(0) },
127             ));
128             let env_region = tcx.mk_region(ty::ReLateBound(
129                 ty::INNERMOST,
130                 ty::BoundRegion { var: ty::BoundVar::from_u32(1), kind: ty::BrEnv },
131             ));
132             let va_list_ty = tcx.bound_type_of(did).subst(tcx, &[region.into()]);
133             (tcx.mk_ref(env_region, ty::TypeAndMut { ty: va_list_ty, mutbl }), va_list_ty)
134         })
135     };
136
137     let (n_tps, n_lts, inputs, output, unsafety) = if name_str.starts_with("atomic_") {
138         let split: Vec<&str> = name_str.split('_').collect();
139         assert!(split.len() >= 2, "Atomic intrinsic in an incorrect format");
140
141         //We only care about the operation here
142         let (n_tps, inputs, output) = match split[1] {
143             "cxchg" | "cxchgweak" => (
144                 1,
145                 vec![tcx.mk_mut_ptr(param(0)), param(0), param(0)],
146                 tcx.intern_tup(&[param(0), tcx.types.bool]),
147             ),
148             "load" => (1, vec![tcx.mk_imm_ptr(param(0))], param(0)),
149             "store" => (1, vec![tcx.mk_mut_ptr(param(0)), param(0)], tcx.mk_unit()),
150
151             "xchg" | "xadd" | "xsub" | "and" | "nand" | "or" | "xor" | "max" | "min" | "umax"
152             | "umin" => (1, vec![tcx.mk_mut_ptr(param(0)), param(0)], param(0)),
153             "fence" | "singlethreadfence" => (0, Vec::new(), tcx.mk_unit()),
154             op => {
155                 tcx.sess.emit_err(UnrecognizedAtomicOperation { span: it.span, op });
156                 return;
157             }
158         };
159         (n_tps, 0, inputs, output, hir::Unsafety::Unsafe)
160     } else {
161         let unsafety = intrinsic_operation_unsafety(intrinsic_name);
162         let (n_tps, inputs, output) = match intrinsic_name {
163             sym::abort => (0, Vec::new(), tcx.types.never),
164             sym::unreachable => (0, Vec::new(), tcx.types.never),
165             sym::breakpoint => (0, Vec::new(), tcx.mk_unit()),
166             sym::size_of | sym::pref_align_of | sym::min_align_of | sym::variant_count => {
167                 (1, Vec::new(), tcx.types.usize)
168             }
169             sym::size_of_val | sym::min_align_of_val => {
170                 (1, vec![tcx.mk_imm_ptr(param(0))], tcx.types.usize)
171             }
172             sym::rustc_peek => (1, vec![param(0)], param(0)),
173             sym::caller_location => (0, vec![], tcx.caller_location_ty()),
174             sym::assert_inhabited | sym::assert_zero_valid | sym::assert_uninit_valid => {
175                 (1, Vec::new(), tcx.mk_unit())
176             }
177             sym::forget => (1, vec![param(0)], tcx.mk_unit()),
178             sym::transmute => (2, vec![param(0)], param(1)),
179             sym::prefetch_read_data
180             | sym::prefetch_write_data
181             | sym::prefetch_read_instruction
182             | sym::prefetch_write_instruction => (
183                 1,
184                 vec![
185                     tcx.mk_ptr(ty::TypeAndMut { ty: param(0), mutbl: hir::Mutability::Not }),
186                     tcx.types.i32,
187                 ],
188                 tcx.mk_unit(),
189             ),
190             sym::drop_in_place => (1, vec![tcx.mk_mut_ptr(param(0))], tcx.mk_unit()),
191             sym::needs_drop => (1, Vec::new(), tcx.types.bool),
192
193             sym::type_name => (1, Vec::new(), tcx.mk_static_str()),
194             sym::type_id => (1, Vec::new(), tcx.types.u64),
195             sym::offset | sym::arith_offset => (
196                 1,
197                 vec![
198                     tcx.mk_ptr(ty::TypeAndMut { ty: param(0), mutbl: hir::Mutability::Not }),
199                     tcx.types.isize,
200                 ],
201                 tcx.mk_ptr(ty::TypeAndMut { ty: param(0), mutbl: hir::Mutability::Not }),
202             ),
203             sym::copy | sym::copy_nonoverlapping => (
204                 1,
205                 vec![
206                     tcx.mk_ptr(ty::TypeAndMut { ty: param(0), mutbl: hir::Mutability::Not }),
207                     tcx.mk_ptr(ty::TypeAndMut { ty: param(0), mutbl: hir::Mutability::Mut }),
208                     tcx.types.usize,
209                 ],
210                 tcx.mk_unit(),
211             ),
212             sym::volatile_copy_memory | sym::volatile_copy_nonoverlapping_memory => (
213                 1,
214                 vec![
215                     tcx.mk_ptr(ty::TypeAndMut { ty: param(0), mutbl: hir::Mutability::Mut }),
216                     tcx.mk_ptr(ty::TypeAndMut { ty: param(0), mutbl: hir::Mutability::Not }),
217                     tcx.types.usize,
218                 ],
219                 tcx.mk_unit(),
220             ),
221             sym::write_bytes | sym::volatile_set_memory => (
222                 1,
223                 vec![
224                     tcx.mk_ptr(ty::TypeAndMut { ty: param(0), mutbl: hir::Mutability::Mut }),
225                     tcx.types.u8,
226                     tcx.types.usize,
227                 ],
228                 tcx.mk_unit(),
229             ),
230             sym::sqrtf32 => (0, vec![tcx.types.f32], tcx.types.f32),
231             sym::sqrtf64 => (0, vec![tcx.types.f64], tcx.types.f64),
232             sym::powif32 => (0, vec![tcx.types.f32, tcx.types.i32], tcx.types.f32),
233             sym::powif64 => (0, vec![tcx.types.f64, tcx.types.i32], tcx.types.f64),
234             sym::sinf32 => (0, vec![tcx.types.f32], tcx.types.f32),
235             sym::sinf64 => (0, vec![tcx.types.f64], tcx.types.f64),
236             sym::cosf32 => (0, vec![tcx.types.f32], tcx.types.f32),
237             sym::cosf64 => (0, vec![tcx.types.f64], tcx.types.f64),
238             sym::powf32 => (0, vec![tcx.types.f32, tcx.types.f32], tcx.types.f32),
239             sym::powf64 => (0, vec![tcx.types.f64, tcx.types.f64], tcx.types.f64),
240             sym::expf32 => (0, vec![tcx.types.f32], tcx.types.f32),
241             sym::expf64 => (0, vec![tcx.types.f64], tcx.types.f64),
242             sym::exp2f32 => (0, vec![tcx.types.f32], tcx.types.f32),
243             sym::exp2f64 => (0, vec![tcx.types.f64], tcx.types.f64),
244             sym::logf32 => (0, vec![tcx.types.f32], tcx.types.f32),
245             sym::logf64 => (0, vec![tcx.types.f64], tcx.types.f64),
246             sym::log10f32 => (0, vec![tcx.types.f32], tcx.types.f32),
247             sym::log10f64 => (0, vec![tcx.types.f64], tcx.types.f64),
248             sym::log2f32 => (0, vec![tcx.types.f32], tcx.types.f32),
249             sym::log2f64 => (0, vec![tcx.types.f64], tcx.types.f64),
250             sym::fmaf32 => (0, vec![tcx.types.f32, tcx.types.f32, tcx.types.f32], tcx.types.f32),
251             sym::fmaf64 => (0, vec![tcx.types.f64, tcx.types.f64, tcx.types.f64], tcx.types.f64),
252             sym::fabsf32 => (0, vec![tcx.types.f32], tcx.types.f32),
253             sym::fabsf64 => (0, vec![tcx.types.f64], tcx.types.f64),
254             sym::minnumf32 => (0, vec![tcx.types.f32, tcx.types.f32], tcx.types.f32),
255             sym::minnumf64 => (0, vec![tcx.types.f64, tcx.types.f64], tcx.types.f64),
256             sym::maxnumf32 => (0, vec![tcx.types.f32, tcx.types.f32], tcx.types.f32),
257             sym::maxnumf64 => (0, vec![tcx.types.f64, tcx.types.f64], tcx.types.f64),
258             sym::copysignf32 => (0, vec![tcx.types.f32, tcx.types.f32], tcx.types.f32),
259             sym::copysignf64 => (0, vec![tcx.types.f64, tcx.types.f64], tcx.types.f64),
260             sym::floorf32 => (0, vec![tcx.types.f32], tcx.types.f32),
261             sym::floorf64 => (0, vec![tcx.types.f64], tcx.types.f64),
262             sym::ceilf32 => (0, vec![tcx.types.f32], tcx.types.f32),
263             sym::ceilf64 => (0, vec![tcx.types.f64], tcx.types.f64),
264             sym::truncf32 => (0, vec![tcx.types.f32], tcx.types.f32),
265             sym::truncf64 => (0, vec![tcx.types.f64], tcx.types.f64),
266             sym::rintf32 => (0, vec![tcx.types.f32], tcx.types.f32),
267             sym::rintf64 => (0, vec![tcx.types.f64], tcx.types.f64),
268             sym::nearbyintf32 => (0, vec![tcx.types.f32], tcx.types.f32),
269             sym::nearbyintf64 => (0, vec![tcx.types.f64], tcx.types.f64),
270             sym::roundf32 => (0, vec![tcx.types.f32], tcx.types.f32),
271             sym::roundf64 => (0, vec![tcx.types.f64], tcx.types.f64),
272
273             sym::volatile_load | sym::unaligned_volatile_load => {
274                 (1, vec![tcx.mk_imm_ptr(param(0))], param(0))
275             }
276             sym::volatile_store | sym::unaligned_volatile_store => {
277                 (1, vec![tcx.mk_mut_ptr(param(0)), param(0)], tcx.mk_unit())
278             }
279
280             sym::ctpop
281             | sym::ctlz
282             | sym::ctlz_nonzero
283             | sym::cttz
284             | sym::cttz_nonzero
285             | sym::bswap
286             | sym::bitreverse => (1, vec![param(0)], param(0)),
287
288             sym::add_with_overflow | sym::sub_with_overflow | sym::mul_with_overflow => {
289                 (1, vec![param(0), param(0)], tcx.intern_tup(&[param(0), tcx.types.bool]))
290             }
291
292             sym::ptr_guaranteed_eq | sym::ptr_guaranteed_ne => {
293                 (1, vec![tcx.mk_imm_ptr(param(0)), tcx.mk_imm_ptr(param(0))], tcx.types.bool)
294             }
295
296             sym::const_allocate => {
297                 (0, vec![tcx.types.usize, tcx.types.usize], tcx.mk_mut_ptr(tcx.types.u8))
298             }
299             sym::const_deallocate => (
300                 0,
301                 vec![tcx.mk_mut_ptr(tcx.types.u8), tcx.types.usize, tcx.types.usize],
302                 tcx.mk_unit(),
303             ),
304
305             sym::ptr_offset_from => {
306                 (1, vec![tcx.mk_imm_ptr(param(0)), tcx.mk_imm_ptr(param(0))], tcx.types.isize)
307             }
308             sym::ptr_offset_from_unsigned => {
309                 (1, vec![tcx.mk_imm_ptr(param(0)), tcx.mk_imm_ptr(param(0))], tcx.types.usize)
310             }
311             sym::unchecked_div | sym::unchecked_rem | sym::exact_div => {
312                 (1, vec![param(0), param(0)], param(0))
313             }
314             sym::unchecked_shl | sym::unchecked_shr | sym::rotate_left | sym::rotate_right => {
315                 (1, vec![param(0), param(0)], param(0))
316             }
317             sym::unchecked_add | sym::unchecked_sub | sym::unchecked_mul => {
318                 (1, vec![param(0), param(0)], param(0))
319             }
320             sym::wrapping_add | sym::wrapping_sub | sym::wrapping_mul => {
321                 (1, vec![param(0), param(0)], param(0))
322             }
323             sym::saturating_add | sym::saturating_sub => (1, vec![param(0), param(0)], param(0)),
324             sym::fadd_fast | sym::fsub_fast | sym::fmul_fast | sym::fdiv_fast | sym::frem_fast => {
325                 (1, vec![param(0), param(0)], param(0))
326             }
327             sym::float_to_int_unchecked => (2, vec![param(0)], param(1)),
328
329             sym::assume => (0, vec![tcx.types.bool], tcx.mk_unit()),
330             sym::likely => (0, vec![tcx.types.bool], tcx.types.bool),
331             sym::unlikely => (0, vec![tcx.types.bool], tcx.types.bool),
332
333             sym::discriminant_value => {
334                 let assoc_items = tcx.associated_item_def_ids(
335                     tcx.require_lang_item(hir::LangItem::DiscriminantKind, None),
336                 );
337                 let discriminant_def_id = assoc_items[0];
338
339                 let br = ty::BoundRegion { var: ty::BoundVar::from_u32(0), kind: ty::BrAnon(0) };
340                 (
341                     1,
342                     vec![
343                         tcx.mk_imm_ref(tcx.mk_region(ty::ReLateBound(ty::INNERMOST, br)), param(0)),
344                     ],
345                     tcx.mk_projection(discriminant_def_id, tcx.mk_substs([param(0).into()].iter())),
346                 )
347             }
348
349             kw::Try => {
350                 let mut_u8 = tcx.mk_mut_ptr(tcx.types.u8);
351                 let try_fn_ty = ty::Binder::dummy(tcx.mk_fn_sig(
352                     iter::once(mut_u8),
353                     tcx.mk_unit(),
354                     false,
355                     hir::Unsafety::Normal,
356                     Abi::Rust,
357                 ));
358                 let catch_fn_ty = ty::Binder::dummy(tcx.mk_fn_sig(
359                     [mut_u8, mut_u8].iter().cloned(),
360                     tcx.mk_unit(),
361                     false,
362                     hir::Unsafety::Normal,
363                     Abi::Rust,
364                 ));
365                 (
366                     0,
367                     vec![tcx.mk_fn_ptr(try_fn_ty), mut_u8, tcx.mk_fn_ptr(catch_fn_ty)],
368                     tcx.types.i32,
369                 )
370             }
371
372             sym::va_start | sym::va_end => match mk_va_list_ty(hir::Mutability::Mut) {
373                 Some((va_list_ref_ty, _)) => (0, vec![va_list_ref_ty], tcx.mk_unit()),
374                 None => bug!("`va_list` language item needed for C-variadic intrinsics"),
375             },
376
377             sym::va_copy => match mk_va_list_ty(hir::Mutability::Not) {
378                 Some((va_list_ref_ty, va_list_ty)) => {
379                     let va_list_ptr_ty = tcx.mk_mut_ptr(va_list_ty);
380                     (0, vec![va_list_ptr_ty, va_list_ref_ty], tcx.mk_unit())
381                 }
382                 None => bug!("`va_list` language item needed for C-variadic intrinsics"),
383             },
384
385             sym::va_arg => match mk_va_list_ty(hir::Mutability::Mut) {
386                 Some((va_list_ref_ty, _)) => (1, vec![va_list_ref_ty], param(0)),
387                 None => bug!("`va_list` language item needed for C-variadic intrinsics"),
388             },
389
390             sym::nontemporal_store => (1, vec![tcx.mk_mut_ptr(param(0)), param(0)], tcx.mk_unit()),
391
392             sym::raw_eq => {
393                 let br = ty::BoundRegion { var: ty::BoundVar::from_u32(0), kind: ty::BrAnon(0) };
394                 let param_ty =
395                     tcx.mk_imm_ref(tcx.mk_region(ty::ReLateBound(ty::INNERMOST, br)), param(0));
396                 (1, vec![param_ty; 2], tcx.types.bool)
397             }
398
399             sym::black_box => (1, vec![param(0)], param(0)),
400
401             sym::const_eval_select => (4, vec![param(0), param(1), param(2)], param(3)),
402
403             other => {
404                 tcx.sess.emit_err(UnrecognizedIntrinsicFunction { span: it.span, name: other });
405                 return;
406             }
407         };
408         (n_tps, 0, inputs, output, unsafety)
409     };
410     let sig = tcx.mk_fn_sig(inputs.into_iter(), output, false, unsafety, Abi::RustIntrinsic);
411     let sig = ty::Binder::bind_with_vars(sig, bound_vars);
412     equate_intrinsic_type(tcx, it, n_tps, n_lts, sig)
413 }
414
415 /// Type-check `extern "platform-intrinsic" { ... }` functions.
416 pub fn check_platform_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>) {
417     let param = |n| {
418         let name = Symbol::intern(&format!("P{}", n));
419         tcx.mk_ty_param(n, name)
420     };
421
422     let name = it.ident.name;
423
424     let (n_tps, inputs, output) = match name {
425         sym::simd_eq | sym::simd_ne | sym::simd_lt | sym::simd_le | sym::simd_gt | sym::simd_ge => {
426             (2, vec![param(0), param(0)], param(1))
427         }
428         sym::simd_add
429         | sym::simd_sub
430         | sym::simd_mul
431         | sym::simd_rem
432         | sym::simd_div
433         | sym::simd_shl
434         | sym::simd_shr
435         | sym::simd_and
436         | sym::simd_or
437         | sym::simd_xor
438         | sym::simd_fmin
439         | sym::simd_fmax
440         | sym::simd_fpow
441         | sym::simd_saturating_add
442         | sym::simd_saturating_sub => (1, vec![param(0), param(0)], param(0)),
443         sym::simd_arith_offset => (2, vec![param(0), param(1)], param(0)),
444         sym::simd_neg
445         | sym::simd_fsqrt
446         | sym::simd_fsin
447         | sym::simd_fcos
448         | sym::simd_fexp
449         | sym::simd_fexp2
450         | sym::simd_flog2
451         | sym::simd_flog10
452         | sym::simd_flog
453         | sym::simd_fabs
454         | sym::simd_ceil
455         | sym::simd_floor
456         | sym::simd_round
457         | sym::simd_trunc => (1, vec![param(0)], param(0)),
458         sym::simd_fpowi => (1, vec![param(0), tcx.types.i32], param(0)),
459         sym::simd_fma => (1, vec![param(0), param(0), param(0)], param(0)),
460         sym::simd_gather => (3, vec![param(0), param(1), param(2)], param(0)),
461         sym::simd_scatter => (3, vec![param(0), param(1), param(2)], tcx.mk_unit()),
462         sym::simd_insert => (2, vec![param(0), tcx.types.u32, param(1)], param(0)),
463         sym::simd_extract => (2, vec![param(0), tcx.types.u32], param(1)),
464         sym::simd_cast | sym::simd_as => (2, vec![param(0)], param(1)),
465         sym::simd_bitmask => (2, vec![param(0)], param(1)),
466         sym::simd_select | sym::simd_select_bitmask => {
467             (2, vec![param(0), param(1), param(1)], param(1))
468         }
469         sym::simd_reduce_all | sym::simd_reduce_any => (1, vec![param(0)], tcx.types.bool),
470         sym::simd_reduce_add_ordered | sym::simd_reduce_mul_ordered => {
471             (2, vec![param(0), param(1)], param(1))
472         }
473         sym::simd_reduce_add_unordered
474         | sym::simd_reduce_mul_unordered
475         | sym::simd_reduce_and
476         | sym::simd_reduce_or
477         | sym::simd_reduce_xor
478         | sym::simd_reduce_min
479         | sym::simd_reduce_max
480         | sym::simd_reduce_min_nanless
481         | sym::simd_reduce_max_nanless => (2, vec![param(0)], param(1)),
482         sym::simd_shuffle => (3, vec![param(0), param(0), param(1)], param(2)),
483         name if name.as_str().starts_with("simd_shuffle") => {
484             match name.as_str()["simd_shuffle".len()..].parse() {
485                 Ok(n) => {
486                     let params = vec![param(0), param(0), tcx.mk_array(tcx.types.u32, n)];
487                     (2, params, param(1))
488                 }
489                 Err(_) => {
490                     let msg =
491                         format!("unrecognized platform-specific intrinsic function: `{name}`");
492                     tcx.sess.struct_span_err(it.span, &msg).emit();
493                     return;
494                 }
495             }
496         }
497         _ => {
498             let msg = format!("unrecognized platform-specific intrinsic function: `{name}`");
499             tcx.sess.struct_span_err(it.span, &msg).emit();
500             return;
501         }
502     };
503
504     let sig = tcx.mk_fn_sig(
505         inputs.into_iter(),
506         output,
507         false,
508         hir::Unsafety::Unsafe,
509         Abi::PlatformIntrinsic,
510     );
511     let sig = ty::Binder::dummy(sig);
512     equate_intrinsic_type(tcx, it, n_tps, 0, sig)
513 }