1 | //! Compiler intrinsics. |
2 | //! |
3 | //! These are the imports making intrinsics available to Rust code. The actual implementations live in the compiler. |
4 | //! Some of these intrinsics are lowered to MIR in <https://github.com/rust-lang/rust/blob/master/compiler/rustc_mir_transform/src/lower_intrinsics.rs>. |
5 | //! The remaining intrinsics are implemented for the LLVM backend in <https://github.com/rust-lang/rust/blob/master/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs> |
6 | //! and <https://github.com/rust-lang/rust/blob/master/compiler/rustc_codegen_llvm/src/intrinsic.rs>, |
7 | //! and for const evaluation in <https://github.com/rust-lang/rust/blob/master/compiler/rustc_const_eval/src/interpret/intrinsics.rs>. |
8 | //! |
9 | //! # Const intrinsics |
10 | //! |
11 | //! In order to make an intrinsic unstable usable at compile-time, copy the implementation from |
12 | //! <https://github.com/rust-lang/miri/blob/master/src/intrinsics> to |
13 | //! <https://github.com/rust-lang/rust/blob/master/compiler/rustc_const_eval/src/interpret/intrinsics.rs> |
14 | //! and make the intrinsic declaration below a `const fn`. This should be done in coordination with |
15 | //! wg-const-eval. |
16 | //! |
17 | //! If an intrinsic is supposed to be used from a `const fn` with a `rustc_const_stable` attribute, |
18 | //! `#[rustc_intrinsic_const_stable_indirect]` needs to be added to the intrinsic. Such a change requires |
19 | //! T-lang approval, because it may bake a feature into the language that cannot be replicated in |
20 | //! user code without compiler support. |
21 | //! |
22 | //! # Volatiles |
23 | //! |
24 | //! The volatile intrinsics provide operations intended to act on I/O |
25 | //! memory, which are guaranteed to not be reordered by the compiler |
26 | //! across other volatile intrinsics. See [`read_volatile`][ptr::read_volatile] |
27 | //! and [`write_volatile`][ptr::write_volatile]. |
28 | //! |
29 | //! # Atomics |
30 | //! |
31 | //! The atomic intrinsics provide common atomic operations on machine |
32 | //! words, with multiple possible memory orderings. See the |
33 | //! [atomic types][atomic] docs for details. |
34 | //! |
35 | //! # Unwinding |
36 | //! |
37 | //! Rust intrinsics may, in general, unwind. If an intrinsic can never unwind, add the |
38 | //! `#[rustc_nounwind]` attribute so that the compiler can make use of this fact. |
39 | //! |
40 | //! However, even for intrinsics that may unwind, rustc assumes that a Rust intrinsics will never |
41 | //! initiate a foreign (non-Rust) unwind, and thus for panic=abort we can always assume that these |
42 | //! intrinsics cannot unwind. |
43 | |
44 | #![unstable ( |
45 | feature = "core_intrinsics" , |
46 | reason = "intrinsics are unlikely to ever be stabilized, instead \ |
47 | they should be used through stabilized interfaces \ |
48 | in the rest of the standard library" , |
49 | issue = "none" |
50 | )] |
51 | #![allow (missing_docs)] |
52 | |
53 | use crate::marker::{ConstParamTy, DiscriminantKind, Tuple}; |
54 | use crate::ptr; |
55 | |
56 | mod bounds; |
57 | pub mod fallback; |
58 | pub mod mir; |
59 | pub mod simd; |
60 | |
61 | // These imports are used for simplifying intra-doc links |
62 | #[allow (unused_imports)] |
63 | #[cfg (all(target_has_atomic = "8" , target_has_atomic = "32" , target_has_atomic = "ptr" ))] |
64 | use crate::sync::atomic::{self, AtomicBool, AtomicI32, AtomicIsize, AtomicU32, Ordering}; |
65 | |
66 | /// A type for atomic ordering parameters for intrinsics. This is a separate type from |
67 | /// `atomic::Ordering` so that we can make it `ConstParamTy` and fix the values used here without a |
68 | /// risk of leaking that to stable code. |
69 | #[derive (Debug, ConstParamTy, PartialEq, Eq)] |
70 | pub enum AtomicOrdering { |
71 | // These values must match the compiler's `AtomicOrdering` defined in |
72 | // `rustc_middle/src/ty/consts/int.rs`! |
73 | Relaxed = 0, |
74 | Release = 1, |
75 | Acquire = 2, |
76 | AcqRel = 3, |
77 | SeqCst = 4, |
78 | } |
79 | |
80 | // N.B., these intrinsics take raw pointers because they mutate aliased |
81 | // memory, which is not valid for either `&` or `&mut`. |
82 | |
83 | /// Stores a value if the current value is the same as the `old` value. |
84 | /// `T` must be an integer or pointer type. |
85 | /// |
86 | /// The stabilized version of this intrinsic is available on the |
87 | /// [`atomic`] types via the `compare_exchange` method. |
88 | /// For example, [`AtomicBool::compare_exchange`]. |
89 | #[rustc_intrinsic ] |
90 | #[rustc_nounwind ] |
91 | pub unsafe fn atomic_cxchg< |
92 | T: Copy, |
93 | const ORD_SUCC: AtomicOrdering, |
94 | const ORD_FAIL: AtomicOrdering, |
95 | >( |
96 | dst: *mut T, |
97 | old: T, |
98 | src: T, |
99 | ) -> (T, bool); |
100 | |
101 | /// Stores a value if the current value is the same as the `old` value. |
102 | /// `T` must be an integer or pointer type. The comparison may spuriously fail. |
103 | /// |
104 | /// The stabilized version of this intrinsic is available on the |
105 | /// [`atomic`] types via the `compare_exchange_weak` method. |
106 | /// For example, [`AtomicBool::compare_exchange_weak`]. |
107 | #[rustc_intrinsic ] |
108 | #[rustc_nounwind ] |
109 | pub unsafe fn atomic_cxchgweak< |
110 | T: Copy, |
111 | const ORD_SUCC: AtomicOrdering, |
112 | const ORD_FAIL: AtomicOrdering, |
113 | >( |
114 | _dst: *mut T, |
115 | _old: T, |
116 | _src: T, |
117 | ) -> (T, bool); |
118 | |
119 | /// Loads the current value of the pointer. |
120 | /// `T` must be an integer or pointer type. |
121 | /// |
122 | /// The stabilized version of this intrinsic is available on the |
123 | /// [`atomic`] types via the `load` method. For example, [`AtomicBool::load`]. |
124 | #[rustc_intrinsic ] |
125 | #[rustc_nounwind ] |
126 | pub unsafe fn atomic_load<T: Copy, const ORD: AtomicOrdering>(src: *const T) -> T; |
127 | |
128 | /// Stores the value at the specified memory location. |
129 | /// `T` must be an integer or pointer type. |
130 | /// |
131 | /// The stabilized version of this intrinsic is available on the |
132 | /// [`atomic`] types via the `store` method. For example, [`AtomicBool::store`]. |
133 | #[rustc_intrinsic ] |
134 | #[rustc_nounwind ] |
135 | pub unsafe fn atomic_store<T: Copy, const ORD: AtomicOrdering>(dst: *mut T, val: T); |
136 | |
137 | /// Stores the value at the specified memory location, returning the old value. |
138 | /// `T` must be an integer or pointer type. |
139 | /// |
140 | /// The stabilized version of this intrinsic is available on the |
141 | /// [`atomic`] types via the `swap` method. For example, [`AtomicBool::swap`]. |
142 | #[rustc_intrinsic ] |
143 | #[rustc_nounwind ] |
144 | pub unsafe fn atomic_xchg<T: Copy, const ORD: AtomicOrdering>(dst: *mut T, src: T) -> T; |
145 | |
146 | /// Adds to the current value, returning the previous value. |
147 | /// `T` must be an integer or pointer type. |
148 | /// If `T` is a pointer type, the provenance of `src` is ignored: both the return value and the new |
149 | /// value stored at `*dst` will have the provenance of the old value stored there. |
150 | /// |
151 | /// The stabilized version of this intrinsic is available on the |
152 | /// [`atomic`] types via the `fetch_add` method. For example, [`AtomicIsize::fetch_add`]. |
153 | #[rustc_intrinsic ] |
154 | #[rustc_nounwind ] |
155 | pub unsafe fn atomic_xadd<T: Copy, const ORD: AtomicOrdering>(dst: *mut T, src: T) -> T; |
156 | |
157 | /// Subtract from the current value, returning the previous value. |
158 | /// `T` must be an integer or pointer type. |
159 | /// If `T` is a pointer type, the provenance of `src` is ignored: both the return value and the new |
160 | /// value stored at `*dst` will have the provenance of the old value stored there. |
161 | /// |
162 | /// The stabilized version of this intrinsic is available on the |
163 | /// [`atomic`] types via the `fetch_sub` method. For example, [`AtomicIsize::fetch_sub`]. |
164 | #[rustc_intrinsic ] |
165 | #[rustc_nounwind ] |
166 | pub unsafe fn atomic_xsub<T: Copy, const ORD: AtomicOrdering>(dst: *mut T, src: T) -> T; |
167 | |
168 | /// Bitwise and with the current value, returning the previous value. |
169 | /// `T` must be an integer or pointer type. |
170 | /// If `T` is a pointer type, the provenance of `src` is ignored: both the return value and the new |
171 | /// value stored at `*dst` will have the provenance of the old value stored there. |
172 | /// |
173 | /// The stabilized version of this intrinsic is available on the |
174 | /// [`atomic`] types via the `fetch_and` method. For example, [`AtomicBool::fetch_and`]. |
175 | #[rustc_intrinsic ] |
176 | #[rustc_nounwind ] |
177 | pub unsafe fn atomic_and<T: Copy, const ORD: AtomicOrdering>(dst: *mut T, src: T) -> T; |
178 | |
179 | /// Bitwise nand with the current value, returning the previous value. |
180 | /// `T` must be an integer or pointer type. |
181 | /// If `T` is a pointer type, the provenance of `src` is ignored: both the return value and the new |
182 | /// value stored at `*dst` will have the provenance of the old value stored there. |
183 | /// |
184 | /// The stabilized version of this intrinsic is available on the |
185 | /// [`AtomicBool`] type via the `fetch_nand` method. For example, [`AtomicBool::fetch_nand`]. |
186 | #[rustc_intrinsic ] |
187 | #[rustc_nounwind ] |
188 | pub unsafe fn atomic_nand<T: Copy, const ORD: AtomicOrdering>(dst: *mut T, src: T) -> T; |
189 | |
190 | /// Bitwise or with the current value, returning the previous value. |
191 | /// `T` must be an integer or pointer type. |
192 | /// If `T` is a pointer type, the provenance of `src` is ignored: both the return value and the new |
193 | /// value stored at `*dst` will have the provenance of the old value stored there. |
194 | /// |
195 | /// The stabilized version of this intrinsic is available on the |
196 | /// [`atomic`] types via the `fetch_or` method. For example, [`AtomicBool::fetch_or`]. |
197 | #[rustc_intrinsic ] |
198 | #[rustc_nounwind ] |
199 | pub unsafe fn atomic_or<T: Copy, const ORD: AtomicOrdering>(dst: *mut T, src: T) -> T; |
200 | |
201 | /// Bitwise xor with the current value, returning the previous value. |
202 | /// `T` must be an integer or pointer type. |
203 | /// If `T` is a pointer type, the provenance of `src` is ignored: both the return value and the new |
204 | /// value stored at `*dst` will have the provenance of the old value stored there. |
205 | /// |
206 | /// The stabilized version of this intrinsic is available on the |
207 | /// [`atomic`] types via the `fetch_xor` method. For example, [`AtomicBool::fetch_xor`]. |
208 | #[rustc_intrinsic ] |
209 | #[rustc_nounwind ] |
210 | pub unsafe fn atomic_xor<T: Copy, const ORD: AtomicOrdering>(dst: *mut T, src: T) -> T; |
211 | |
212 | /// Maximum with the current value using a signed comparison. |
213 | /// `T` must be a signed integer type. |
214 | /// |
215 | /// The stabilized version of this intrinsic is available on the |
216 | /// [`atomic`] signed integer types via the `fetch_max` method. For example, [`AtomicI32::fetch_max`]. |
217 | #[rustc_intrinsic ] |
218 | #[rustc_nounwind ] |
219 | pub unsafe fn atomic_max<T: Copy, const ORD: AtomicOrdering>(dst: *mut T, src: T) -> T; |
220 | |
221 | /// Minimum with the current value using a signed comparison. |
222 | /// `T` must be a signed integer type. |
223 | /// |
224 | /// The stabilized version of this intrinsic is available on the |
225 | /// [`atomic`] signed integer types via the `fetch_min` method. For example, [`AtomicI32::fetch_min`]. |
226 | #[rustc_intrinsic ] |
227 | #[rustc_nounwind ] |
228 | pub unsafe fn atomic_min<T: Copy, const ORD: AtomicOrdering>(dst: *mut T, src: T) -> T; |
229 | |
230 | /// Minimum with the current value using an unsigned comparison. |
231 | /// `T` must be an unsigned integer type. |
232 | /// |
233 | /// The stabilized version of this intrinsic is available on the |
234 | /// [`atomic`] unsigned integer types via the `fetch_min` method. For example, [`AtomicU32::fetch_min`]. |
235 | #[rustc_intrinsic ] |
236 | #[rustc_nounwind ] |
237 | pub unsafe fn atomic_umin<T: Copy, const ORD: AtomicOrdering>(dst: *mut T, src: T) -> T; |
238 | |
239 | /// Maximum with the current value using an unsigned comparison. |
240 | /// `T` must be an unsigned integer type. |
241 | /// |
242 | /// The stabilized version of this intrinsic is available on the |
243 | /// [`atomic`] unsigned integer types via the `fetch_max` method. For example, [`AtomicU32::fetch_max`]. |
244 | #[rustc_intrinsic ] |
245 | #[rustc_nounwind ] |
246 | pub unsafe fn atomic_umax<T: Copy, const ORD: AtomicOrdering>(dst: *mut T, src: T) -> T; |
247 | |
248 | /// An atomic fence. |
249 | /// |
250 | /// The stabilized version of this intrinsic is available in |
251 | /// [`atomic::fence`]. |
252 | #[rustc_intrinsic ] |
253 | #[rustc_nounwind ] |
254 | pub unsafe fn atomic_fence<const ORD: AtomicOrdering>(); |
255 | |
256 | /// An atomic fence for synchronization within a single thread. |
257 | /// |
258 | /// The stabilized version of this intrinsic is available in |
259 | /// [`atomic::compiler_fence`]. |
260 | #[rustc_intrinsic ] |
261 | #[rustc_nounwind ] |
262 | pub unsafe fn atomic_singlethreadfence<const ORD: AtomicOrdering>(); |
263 | |
264 | /// The `prefetch` intrinsic is a hint to the code generator to insert a prefetch instruction |
265 | /// if supported; otherwise, it is a no-op. |
266 | /// Prefetches have no effect on the behavior of the program but can change its performance |
267 | /// characteristics. |
268 | /// |
269 | /// The `locality` argument must be a constant integer and is a temporal locality specifier |
270 | /// ranging from (0) - no locality, to (3) - extremely local keep in cache. |
271 | /// |
272 | /// This intrinsic does not have a stable counterpart. |
273 | #[rustc_intrinsic ] |
274 | #[rustc_nounwind ] |
275 | pub unsafe fn prefetch_read_data<T>(data: *const T, locality: i32); |
276 | /// The `prefetch` intrinsic is a hint to the code generator to insert a prefetch instruction |
277 | /// if supported; otherwise, it is a no-op. |
278 | /// Prefetches have no effect on the behavior of the program but can change its performance |
279 | /// characteristics. |
280 | /// |
281 | /// The `locality` argument must be a constant integer and is a temporal locality specifier |
282 | /// ranging from (0) - no locality, to (3) - extremely local keep in cache. |
283 | /// |
284 | /// This intrinsic does not have a stable counterpart. |
285 | #[rustc_intrinsic ] |
286 | #[rustc_nounwind ] |
287 | pub unsafe fn prefetch_write_data<T>(data: *const T, locality: i32); |
288 | /// The `prefetch` intrinsic is a hint to the code generator to insert a prefetch instruction |
289 | /// if supported; otherwise, it is a no-op. |
290 | /// Prefetches have no effect on the behavior of the program but can change its performance |
291 | /// characteristics. |
292 | /// |
293 | /// The `locality` argument must be a constant integer and is a temporal locality specifier |
294 | /// ranging from (0) - no locality, to (3) - extremely local keep in cache. |
295 | /// |
296 | /// This intrinsic does not have a stable counterpart. |
297 | #[rustc_intrinsic ] |
298 | #[rustc_nounwind ] |
299 | pub unsafe fn prefetch_read_instruction<T>(data: *const T, locality: i32); |
300 | /// The `prefetch` intrinsic is a hint to the code generator to insert a prefetch instruction |
301 | /// if supported; otherwise, it is a no-op. |
302 | /// Prefetches have no effect on the behavior of the program but can change its performance |
303 | /// characteristics. |
304 | /// |
305 | /// The `locality` argument must be a constant integer and is a temporal locality specifier |
306 | /// ranging from (0) - no locality, to (3) - extremely local keep in cache. |
307 | /// |
308 | /// This intrinsic does not have a stable counterpart. |
309 | #[rustc_intrinsic ] |
310 | #[rustc_nounwind ] |
311 | pub unsafe fn prefetch_write_instruction<T>(data: *const T, locality: i32); |
312 | |
313 | /// Executes a breakpoint trap, for inspection by a debugger. |
314 | /// |
315 | /// This intrinsic does not have a stable counterpart. |
316 | #[rustc_intrinsic ] |
317 | #[rustc_nounwind ] |
318 | pub fn breakpoint(); |
319 | |
320 | /// Magic intrinsic that derives its meaning from attributes |
321 | /// attached to the function. |
322 | /// |
323 | /// For example, dataflow uses this to inject static assertions so |
324 | /// that `rustc_peek(potentially_uninitialized)` would actually |
325 | /// double-check that dataflow did indeed compute that it is |
326 | /// uninitialized at that point in the control flow. |
327 | /// |
328 | /// This intrinsic should not be used outside of the compiler. |
329 | #[rustc_nounwind ] |
330 | #[rustc_intrinsic ] |
331 | pub fn rustc_peek<T>(_: T) -> T; |
332 | |
333 | /// Aborts the execution of the process. |
334 | /// |
335 | /// Note that, unlike most intrinsics, this is safe to call; |
336 | /// it does not require an `unsafe` block. |
337 | /// Therefore, implementations must not require the user to uphold |
338 | /// any safety invariants. |
339 | /// |
340 | /// [`std::process::abort`](../../std/process/fn.abort.html) is to be preferred if possible, |
341 | /// as its behavior is more user-friendly and more stable. |
342 | /// |
343 | /// The current implementation of `intrinsics::abort` is to invoke an invalid instruction, |
344 | /// on most platforms. |
345 | /// On Unix, the |
346 | /// process will probably terminate with a signal like `SIGABRT`, `SIGILL`, `SIGTRAP`, `SIGSEGV` or |
347 | /// `SIGBUS`. The precise behavior is not guaranteed and not stable. |
348 | #[rustc_nounwind ] |
349 | #[rustc_intrinsic ] |
350 | pub fn abort() -> !; |
351 | |
352 | /// Informs the optimizer that this point in the code is not reachable, |
353 | /// enabling further optimizations. |
354 | /// |
355 | /// N.B., this is very different from the `unreachable!()` macro: Unlike the |
356 | /// macro, which panics when it is executed, it is *undefined behavior* to |
357 | /// reach code marked with this function. |
358 | /// |
359 | /// The stabilized version of this intrinsic is [`core::hint::unreachable_unchecked`]. |
360 | #[rustc_intrinsic_const_stable_indirect] |
361 | #[rustc_nounwind ] |
362 | #[rustc_intrinsic ] |
363 | pub const unsafe fn unreachable() -> !; |
364 | |
365 | /// Informs the optimizer that a condition is always true. |
366 | /// If the condition is false, the behavior is undefined. |
367 | /// |
368 | /// No code is generated for this intrinsic, but the optimizer will try |
369 | /// to preserve it (and its condition) between passes, which may interfere |
370 | /// with optimization of surrounding code and reduce performance. It should |
371 | /// not be used if the invariant can be discovered by the optimizer on its |
372 | /// own, or if it does not enable any significant optimizations. |
373 | /// |
374 | /// The stabilized version of this intrinsic is [`core::hint::assert_unchecked`]. |
375 | #[rustc_intrinsic_const_stable_indirect] |
376 | #[rustc_nounwind ] |
377 | #[unstable (feature = "core_intrinsics" , issue = "none" )] |
378 | #[rustc_intrinsic ] |
379 | pub const unsafe fn assume(b: bool) { |
380 | if !b { |
381 | // SAFETY: the caller must guarantee the argument is never `false` |
382 | unsafe { unreachable() } |
383 | } |
384 | } |
385 | |
386 | /// Hints to the compiler that current code path is cold. |
387 | /// |
388 | /// Note that, unlike most intrinsics, this is safe to call; |
389 | /// it does not require an `unsafe` block. |
390 | /// Therefore, implementations must not require the user to uphold |
391 | /// any safety invariants. |
392 | /// |
393 | /// This intrinsic does not have a stable counterpart. |
394 | #[unstable (feature = "core_intrinsics" , issue = "none" )] |
395 | #[rustc_intrinsic ] |
396 | #[rustc_nounwind ] |
397 | #[miri::intrinsic_fallback_is_spec] |
398 | #[cold ] |
399 | pub const fn cold_path() {} |
400 | |
401 | /// Hints to the compiler that branch condition is likely to be true. |
402 | /// Returns the value passed to it. |
403 | /// |
404 | /// Any use other than with `if` statements will probably not have an effect. |
405 | /// |
406 | /// Note that, unlike most intrinsics, this is safe to call; |
407 | /// it does not require an `unsafe` block. |
408 | /// Therefore, implementations must not require the user to uphold |
409 | /// any safety invariants. |
410 | /// |
411 | /// This intrinsic does not have a stable counterpart. |
412 | #[unstable (feature = "core_intrinsics" , issue = "none" )] |
413 | #[rustc_nounwind ] |
414 | #[inline (always)] |
415 | pub const fn likely(b: bool) -> bool { |
416 | if b { |
417 | true |
418 | } else { |
419 | cold_path(); |
420 | false |
421 | } |
422 | } |
423 | |
424 | /// Hints to the compiler that branch condition is likely to be false. |
425 | /// Returns the value passed to it. |
426 | /// |
427 | /// Any use other than with `if` statements will probably not have an effect. |
428 | /// |
429 | /// Note that, unlike most intrinsics, this is safe to call; |
430 | /// it does not require an `unsafe` block. |
431 | /// Therefore, implementations must not require the user to uphold |
432 | /// any safety invariants. |
433 | /// |
434 | /// This intrinsic does not have a stable counterpart. |
435 | #[unstable (feature = "core_intrinsics" , issue = "none" )] |
436 | #[rustc_nounwind ] |
437 | #[inline (always)] |
438 | pub const fn unlikely(b: bool) -> bool { |
439 | if b { |
440 | cold_path(); |
441 | true |
442 | } else { |
443 | false |
444 | } |
445 | } |
446 | |
447 | /// Returns either `true_val` or `false_val` depending on condition `b` with a |
448 | /// hint to the compiler that this condition is unlikely to be correctly |
449 | /// predicted by a CPU's branch predictor (e.g. a binary search). |
450 | /// |
451 | /// This is otherwise functionally equivalent to `if b { true_val } else { false_val }`. |
452 | /// |
453 | /// Note that, unlike most intrinsics, this is safe to call; |
454 | /// it does not require an `unsafe` block. |
455 | /// Therefore, implementations must not require the user to uphold |
456 | /// any safety invariants. |
457 | /// |
458 | /// The public form of this instrinsic is [`core::hint::select_unpredictable`]. |
459 | /// However unlike the public form, the intrinsic will not drop the value that |
460 | /// is not selected. |
461 | #[unstable (feature = "core_intrinsics" , issue = "none" )] |
462 | #[rustc_intrinsic ] |
463 | #[rustc_nounwind ] |
464 | #[miri::intrinsic_fallback_is_spec] |
465 | #[inline ] |
466 | pub fn select_unpredictable<T>(b: bool, true_val: T, false_val: T) -> T { |
467 | if b { true_val } else { false_val } |
468 | } |
469 | |
470 | /// A guard for unsafe functions that cannot ever be executed if `T` is uninhabited: |
471 | /// This will statically either panic, or do nothing. |
472 | /// |
473 | /// This intrinsic does not have a stable counterpart. |
474 | #[rustc_intrinsic_const_stable_indirect] |
475 | #[rustc_nounwind ] |
476 | #[rustc_intrinsic ] |
477 | pub const fn assert_inhabited<T>(); |
478 | |
479 | /// A guard for unsafe functions that cannot ever be executed if `T` does not permit |
480 | /// zero-initialization: This will statically either panic, or do nothing. |
481 | /// |
482 | /// This intrinsic does not have a stable counterpart. |
483 | #[rustc_intrinsic_const_stable_indirect] |
484 | #[rustc_nounwind ] |
485 | #[rustc_intrinsic ] |
486 | pub const fn assert_zero_valid<T>(); |
487 | |
488 | /// A guard for `std::mem::uninitialized`. This will statically either panic, or do nothing. |
489 | /// |
490 | /// This intrinsic does not have a stable counterpart. |
491 | #[rustc_intrinsic_const_stable_indirect] |
492 | #[rustc_nounwind ] |
493 | #[rustc_intrinsic ] |
494 | pub const fn assert_mem_uninitialized_valid<T>(); |
495 | |
496 | /// Gets a reference to a static `Location` indicating where it was called. |
497 | /// |
498 | /// Note that, unlike most intrinsics, this is safe to call; |
499 | /// it does not require an `unsafe` block. |
500 | /// Therefore, implementations must not require the user to uphold |
501 | /// any safety invariants. |
502 | /// |
503 | /// Consider using [`core::panic::Location::caller`] instead. |
504 | #[rustc_intrinsic_const_stable_indirect] |
505 | #[rustc_nounwind ] |
506 | #[rustc_intrinsic ] |
507 | pub const fn caller_location() -> &'static crate::panic::Location<'static>; |
508 | |
509 | /// Moves a value out of scope without running drop glue. |
510 | /// |
511 | /// This exists solely for [`crate::mem::forget_unsized`]; normal `forget` uses |
512 | /// `ManuallyDrop` instead. |
513 | /// |
514 | /// Note that, unlike most intrinsics, this is safe to call; |
515 | /// it does not require an `unsafe` block. |
516 | /// Therefore, implementations must not require the user to uphold |
517 | /// any safety invariants. |
518 | #[rustc_intrinsic_const_stable_indirect] |
519 | #[rustc_nounwind ] |
520 | #[rustc_intrinsic ] |
521 | pub const fn forget<T: ?Sized>(_: T); |
522 | |
523 | /// Reinterprets the bits of a value of one type as another type. |
524 | /// |
525 | /// Both types must have the same size. Compilation will fail if this is not guaranteed. |
526 | /// |
527 | /// `transmute` is semantically equivalent to a bitwise move of one type |
528 | /// into another. It copies the bits from the source value into the |
529 | /// destination value, then forgets the original. Note that source and destination |
530 | /// are passed by-value, which means if `Src` or `Dst` contain padding, that padding |
531 | /// is *not* guaranteed to be preserved by `transmute`. |
532 | /// |
533 | /// Both the argument and the result must be [valid](../../nomicon/what-unsafe-does.html) at |
534 | /// their given type. Violating this condition leads to [undefined behavior][ub]. The compiler |
535 | /// will generate code *assuming that you, the programmer, ensure that there will never be |
536 | /// undefined behavior*. It is therefore your responsibility to guarantee that every value |
537 | /// passed to `transmute` is valid at both types `Src` and `Dst`. Failing to uphold this condition |
538 | /// may lead to unexpected and unstable compilation results. This makes `transmute` **incredibly |
539 | /// unsafe**. `transmute` should be the absolute last resort. |
540 | /// |
541 | /// Because `transmute` is a by-value operation, alignment of the *transmuted values |
542 | /// themselves* is not a concern. As with any other function, the compiler already ensures |
543 | /// both `Src` and `Dst` are properly aligned. However, when transmuting values that *point |
544 | /// elsewhere* (such as pointers, references, boxes…), the caller has to ensure proper |
545 | /// alignment of the pointed-to values. |
546 | /// |
547 | /// The [nomicon](../../nomicon/transmutes.html) has additional documentation. |
548 | /// |
549 | /// [ub]: ../../reference/behavior-considered-undefined.html |
550 | /// |
551 | /// # Transmutation between pointers and integers |
552 | /// |
553 | /// Special care has to be taken when transmuting between pointers and integers, e.g. |
554 | /// transmuting between `*const ()` and `usize`. |
555 | /// |
556 | /// Transmuting *pointers to integers* in a `const` context is [undefined behavior][ub], unless |
557 | /// the pointer was originally created *from* an integer. (That includes this function |
558 | /// specifically, integer-to-pointer casts, and helpers like [`dangling`][crate::ptr::dangling], |
559 | /// but also semantically-equivalent conversions such as punning through `repr(C)` union |
560 | /// fields.) Any attempt to use the resulting value for integer operations will abort |
561 | /// const-evaluation. (And even outside `const`, such transmutation is touching on many |
562 | /// unspecified aspects of the Rust memory model and should be avoided. See below for |
563 | /// alternatives.) |
564 | /// |
565 | /// Transmuting *integers to pointers* is a largely unspecified operation. It is likely *not* |
566 | /// equivalent to an `as` cast. Doing non-zero-sized memory accesses with a pointer constructed |
567 | /// this way is currently considered undefined behavior. |
568 | /// |
569 | /// All this also applies when the integer is nested inside an array, tuple, struct, or enum. |
570 | /// However, `MaybeUninit<usize>` is not considered an integer type for the purpose of this |
571 | /// section. Transmuting `*const ()` to `MaybeUninit<usize>` is fine---but then calling |
572 | /// `assume_init()` on that result is considered as completing the pointer-to-integer transmute |
573 | /// and thus runs into the issues discussed above. |
574 | /// |
575 | /// In particular, doing a pointer-to-integer-to-pointer roundtrip via `transmute` is *not* a |
576 | /// lossless process. If you want to round-trip a pointer through an integer in a way that you |
577 | /// can get back the original pointer, you need to use `as` casts, or replace the integer type |
578 | /// by `MaybeUninit<$int>` (and never call `assume_init()`). If you are looking for a way to |
579 | /// store data of arbitrary type, also use `MaybeUninit<T>` (that will also handle uninitialized |
580 | /// memory due to padding). If you specifically need to store something that is "either an |
581 | /// integer or a pointer", use `*mut ()`: integers can be converted to pointers and back without |
582 | /// any loss (via `as` casts or via `transmute`). |
583 | /// |
584 | /// # Examples |
585 | /// |
586 | /// There are a few things that `transmute` is really useful for. |
587 | /// |
588 | /// Turning a pointer into a function pointer. This is *not* portable to |
589 | /// machines where function pointers and data pointers have different sizes. |
590 | /// |
591 | /// ``` |
592 | /// fn foo() -> i32 { |
593 | /// 0 |
594 | /// } |
595 | /// // Crucially, we `as`-cast to a raw pointer before `transmute`ing to a function pointer. |
596 | /// // This avoids an integer-to-pointer `transmute`, which can be problematic. |
597 | /// // Transmuting between raw pointers and function pointers (i.e., two pointer types) is fine. |
598 | /// let pointer = foo as *const (); |
599 | /// let function = unsafe { |
600 | /// std::mem::transmute::<*const (), fn() -> i32>(pointer) |
601 | /// }; |
602 | /// assert_eq!(function(), 0); |
603 | /// ``` |
604 | /// |
605 | /// Extending a lifetime, or shortening an invariant lifetime. This is |
606 | /// advanced, very unsafe Rust! |
607 | /// |
608 | /// ``` |
609 | /// struct R<'a>(&'a i32); |
610 | /// unsafe fn extend_lifetime<'b>(r: R<'b>) -> R<'static> { |
611 | /// unsafe { std::mem::transmute::<R<'b>, R<'static>>(r) } |
612 | /// } |
613 | /// |
614 | /// unsafe fn shorten_invariant_lifetime<'b, 'c>(r: &'b mut R<'static>) |
615 | /// -> &'b mut R<'c> { |
616 | /// unsafe { std::mem::transmute::<&'b mut R<'static>, &'b mut R<'c>>(r) } |
617 | /// } |
618 | /// ``` |
619 | /// |
620 | /// # Alternatives |
621 | /// |
622 | /// Don't despair: many uses of `transmute` can be achieved through other means. |
623 | /// Below are common applications of `transmute` which can be replaced with safer |
624 | /// constructs. |
625 | /// |
626 | /// Turning raw bytes (`[u8; SZ]`) into `u32`, `f64`, etc.: |
627 | /// |
628 | /// ``` |
629 | /// # #![allow(unnecessary_transmutes)] |
630 | /// let raw_bytes = [0x78, 0x56, 0x34, 0x12]; |
631 | /// |
632 | /// let num = unsafe { |
633 | /// std::mem::transmute::<[u8; 4], u32>(raw_bytes) |
634 | /// }; |
635 | /// |
636 | /// // use `u32::from_ne_bytes` instead |
637 | /// let num = u32::from_ne_bytes(raw_bytes); |
638 | /// // or use `u32::from_le_bytes` or `u32::from_be_bytes` to specify the endianness |
639 | /// let num = u32::from_le_bytes(raw_bytes); |
640 | /// assert_eq!(num, 0x12345678); |
641 | /// let num = u32::from_be_bytes(raw_bytes); |
642 | /// assert_eq!(num, 0x78563412); |
643 | /// ``` |
644 | /// |
645 | /// Turning a pointer into a `usize`: |
646 | /// |
647 | /// ```no_run |
648 | /// let ptr = &0; |
649 | /// let ptr_num_transmute = unsafe { |
650 | /// std::mem::transmute::<&i32, usize>(ptr) |
651 | /// }; |
652 | /// |
653 | /// // Use an `as` cast instead |
654 | /// let ptr_num_cast = ptr as *const i32 as usize; |
655 | /// ``` |
656 | /// |
657 | /// Note that using `transmute` to turn a pointer to a `usize` is (as noted above) [undefined |
658 | /// behavior][ub] in `const` contexts. Also outside of consts, this operation might not behave |
659 | /// as expected -- this is touching on many unspecified aspects of the Rust memory model. |
660 | /// Depending on what the code is doing, the following alternatives are preferable to |
661 | /// pointer-to-integer transmutation: |
662 | /// - If the code just wants to store data of arbitrary type in some buffer and needs to pick a |
663 | /// type for that buffer, it can use [`MaybeUninit`][crate::mem::MaybeUninit]. |
664 | /// - If the code actually wants to work on the address the pointer points to, it can use `as` |
665 | /// casts or [`ptr.addr()`][pointer::addr]. |
666 | /// |
667 | /// Turning a `*mut T` into a `&mut T`: |
668 | /// |
669 | /// ``` |
670 | /// let ptr: *mut i32 = &mut 0; |
671 | /// let ref_transmuted = unsafe { |
672 | /// std::mem::transmute::<*mut i32, &mut i32>(ptr) |
673 | /// }; |
674 | /// |
675 | /// // Use a reborrow instead |
676 | /// let ref_casted = unsafe { &mut *ptr }; |
677 | /// ``` |
678 | /// |
679 | /// Turning a `&mut T` into a `&mut U`: |
680 | /// |
681 | /// ``` |
682 | /// let ptr = &mut 0; |
683 | /// let val_transmuted = unsafe { |
684 | /// std::mem::transmute::<&mut i32, &mut u32>(ptr) |
685 | /// }; |
686 | /// |
687 | /// // Now, put together `as` and reborrowing - note the chaining of `as` |
688 | /// // `as` is not transitive |
689 | /// let val_casts = unsafe { &mut *(ptr as *mut i32 as *mut u32) }; |
690 | /// ``` |
691 | /// |
692 | /// Turning a `&str` into a `&[u8]`: |
693 | /// |
694 | /// ``` |
695 | /// // this is not a good way to do this. |
696 | /// let slice = unsafe { std::mem::transmute::<&str, &[u8]>("Rust" ) }; |
697 | /// assert_eq!(slice, &[82, 117, 115, 116]); |
698 | /// |
699 | /// // You could use `str::as_bytes` |
700 | /// let slice = "Rust" .as_bytes(); |
701 | /// assert_eq!(slice, &[82, 117, 115, 116]); |
702 | /// |
703 | /// // Or, just use a byte string, if you have control over the string |
704 | /// // literal |
705 | /// assert_eq!(b"Rust" , &[82, 117, 115, 116]); |
706 | /// ``` |
707 | /// |
708 | /// Turning a `Vec<&T>` into a `Vec<Option<&T>>`. |
709 | /// |
710 | /// To transmute the inner type of the contents of a container, you must make sure to not |
711 | /// violate any of the container's invariants. For `Vec`, this means that both the size |
712 | /// *and alignment* of the inner types have to match. Other containers might rely on the |
713 | /// size of the type, alignment, or even the `TypeId`, in which case transmuting wouldn't |
714 | /// be possible at all without violating the container invariants. |
715 | /// |
716 | /// ``` |
717 | /// let store = [0, 1, 2, 3]; |
718 | /// let v_orig = store.iter().collect::<Vec<&i32>>(); |
719 | /// |
720 | /// // clone the vector as we will reuse them later |
721 | /// let v_clone = v_orig.clone(); |
722 | /// |
723 | /// // Using transmute: this relies on the unspecified data layout of `Vec`, which is a |
724 | /// // bad idea and could cause Undefined Behavior. |
725 | /// // However, it is no-copy. |
726 | /// let v_transmuted = unsafe { |
727 | /// std::mem::transmute::<Vec<&i32>, Vec<Option<&i32>>>(v_clone) |
728 | /// }; |
729 | /// |
730 | /// let v_clone = v_orig.clone(); |
731 | /// |
732 | /// // This is the suggested, safe way. |
733 | /// // It may copy the entire vector into a new one though, but also may not. |
734 | /// let v_collected = v_clone.into_iter() |
735 | /// .map(Some) |
736 | /// .collect::<Vec<Option<&i32>>>(); |
737 | /// |
738 | /// let v_clone = v_orig.clone(); |
739 | /// |
740 | /// // This is the proper no-copy, unsafe way of "transmuting" a `Vec`, without relying on the |
741 | /// // data layout. Instead of literally calling `transmute`, we perform a pointer cast, but |
742 | /// // in terms of converting the original inner type (`&i32`) to the new one (`Option<&i32>`), |
743 | /// // this has all the same caveats. Besides the information provided above, also consult the |
744 | /// // [`from_raw_parts`] documentation. |
745 | /// let v_from_raw = unsafe { |
746 | // FIXME Update this when vec_into_raw_parts is stabilized |
747 | /// // Ensure the original vector is not dropped. |
748 | /// let mut v_clone = std::mem::ManuallyDrop::new(v_clone); |
749 | /// Vec::from_raw_parts(v_clone.as_mut_ptr() as *mut Option<&i32>, |
750 | /// v_clone.len(), |
751 | /// v_clone.capacity()) |
752 | /// }; |
753 | /// ``` |
754 | /// |
755 | /// [`from_raw_parts`]: ../../std/vec/struct.Vec.html#method.from_raw_parts |
756 | /// |
757 | /// Implementing `split_at_mut`: |
758 | /// |
759 | /// ``` |
760 | /// use std::{slice, mem}; |
761 | /// |
762 | /// // There are multiple ways to do this, and there are multiple problems |
763 | /// // with the following (transmute) way. |
764 | /// fn split_at_mut_transmute<T>(slice: &mut [T], mid: usize) |
765 | /// -> (&mut [T], &mut [T]) { |
766 | /// let len = slice.len(); |
767 | /// assert!(mid <= len); |
768 | /// unsafe { |
769 | /// let slice2 = mem::transmute::<&mut [T], &mut [T]>(slice); |
770 | /// // first: transmute is not type safe; all it checks is that T and |
771 | /// // U are of the same size. Second, right here, you have two |
772 | /// // mutable references pointing to the same memory. |
773 | /// (&mut slice[0..mid], &mut slice2[mid..len]) |
774 | /// } |
775 | /// } |
776 | /// |
777 | /// // This gets rid of the type safety problems; `&mut *` will *only* give |
778 | /// // you a `&mut T` from a `&mut T` or `*mut T`. |
779 | /// fn split_at_mut_casts<T>(slice: &mut [T], mid: usize) |
780 | /// -> (&mut [T], &mut [T]) { |
781 | /// let len = slice.len(); |
782 | /// assert!(mid <= len); |
783 | /// unsafe { |
784 | /// let slice2 = &mut *(slice as *mut [T]); |
785 | /// // however, you still have two mutable references pointing to |
786 | /// // the same memory. |
787 | /// (&mut slice[0..mid], &mut slice2[mid..len]) |
788 | /// } |
789 | /// } |
790 | /// |
791 | /// // This is how the standard library does it. This is the best method, if |
792 | /// // you need to do something like this |
793 | /// fn split_at_stdlib<T>(slice: &mut [T], mid: usize) |
794 | /// -> (&mut [T], &mut [T]) { |
795 | /// let len = slice.len(); |
796 | /// assert!(mid <= len); |
797 | /// unsafe { |
798 | /// let ptr = slice.as_mut_ptr(); |
799 | /// // This now has three mutable references pointing at the same |
800 | /// // memory. `slice`, the rvalue ret.0, and the rvalue ret.1. |
801 | /// // `slice` is never used after `let ptr = ...`, and so one can |
802 | /// // treat it as "dead", and therefore, you only have two real |
803 | /// // mutable slices. |
804 | /// (slice::from_raw_parts_mut(ptr, mid), |
805 | /// slice::from_raw_parts_mut(ptr.add(mid), len - mid)) |
806 | /// } |
807 | /// } |
808 | /// ``` |
809 | #[stable (feature = "rust1" , since = "1.0.0" )] |
810 | #[rustc_allowed_through_unstable_modules = "import this function via `std::mem` instead" ] |
811 | #[rustc_const_stable (feature = "const_transmute" , since = "1.56.0" )] |
812 | #[rustc_diagnostic_item = "transmute" ] |
813 | #[rustc_nounwind ] |
814 | #[rustc_intrinsic ] |
815 | pub const unsafe fn transmute<Src, Dst>(src: Src) -> Dst; |
816 | |
817 | /// Like [`transmute`], but even less checked at compile-time: rather than |
818 | /// giving an error for `size_of::<Src>() != size_of::<Dst>()`, it's |
819 | /// **Undefined Behavior** at runtime. |
820 | /// |
821 | /// Prefer normal `transmute` where possible, for the extra checking, since |
822 | /// both do exactly the same thing at runtime, if they both compile. |
823 | /// |
824 | /// This is not expected to ever be exposed directly to users, rather it |
825 | /// may eventually be exposed through some more-constrained API. |
826 | #[rustc_intrinsic_const_stable_indirect] |
827 | #[rustc_nounwind ] |
828 | #[rustc_intrinsic ] |
829 | pub const unsafe fn transmute_unchecked<Src, Dst>(src: Src) -> Dst; |
830 | |
831 | /// Returns `true` if the actual type given as `T` requires drop |
832 | /// glue; returns `false` if the actual type provided for `T` |
833 | /// implements `Copy`. |
834 | /// |
835 | /// If the actual type neither requires drop glue nor implements |
836 | /// `Copy`, then the return value of this function is unspecified. |
837 | /// |
838 | /// Note that, unlike most intrinsics, this is safe to call; |
839 | /// it does not require an `unsafe` block. |
840 | /// Therefore, implementations must not require the user to uphold |
841 | /// any safety invariants. |
842 | /// |
843 | /// The stabilized version of this intrinsic is [`mem::needs_drop`](crate::mem::needs_drop). |
844 | #[rustc_intrinsic_const_stable_indirect] |
845 | #[rustc_nounwind ] |
846 | #[rustc_intrinsic ] |
847 | pub const fn needs_drop<T: ?Sized>() -> bool; |
848 | |
849 | /// Calculates the offset from a pointer. |
850 | /// |
851 | /// This is implemented as an intrinsic to avoid converting to and from an |
852 | /// integer, since the conversion would throw away aliasing information. |
853 | /// |
854 | /// This can only be used with `Ptr` as a raw pointer type (`*mut` or `*const`) |
855 | /// to a `Sized` pointee and with `Delta` as `usize` or `isize`. Any other |
856 | /// instantiations may arbitrarily misbehave, and that's *not* a compiler bug. |
857 | /// |
858 | /// # Safety |
859 | /// |
860 | /// If the computed offset is non-zero, then both the starting and resulting pointer must be |
861 | /// either in bounds or at the end of an allocation. If either pointer is out |
862 | /// of bounds or arithmetic overflow occurs then this operation is undefined behavior. |
863 | /// |
864 | /// The stabilized version of this intrinsic is [`pointer::offset`]. |
865 | #[must_use = "returns a new pointer rather than modifying its argument" ] |
866 | #[rustc_intrinsic_const_stable_indirect] |
867 | #[rustc_nounwind ] |
868 | #[rustc_intrinsic ] |
869 | pub const unsafe fn offset<Ptr: bounds::BuiltinDeref, Delta>(dst: Ptr, offset: Delta) -> Ptr; |
870 | |
871 | /// Calculates the offset from a pointer, potentially wrapping. |
872 | /// |
873 | /// This is implemented as an intrinsic to avoid converting to and from an |
874 | /// integer, since the conversion inhibits certain optimizations. |
875 | /// |
876 | /// # Safety |
877 | /// |
878 | /// Unlike the `offset` intrinsic, this intrinsic does not restrict the |
879 | /// resulting pointer to point into or at the end of an allocated |
880 | /// object, and it wraps with two's complement arithmetic. The resulting |
881 | /// value is not necessarily valid to be used to actually access memory. |
882 | /// |
883 | /// The stabilized version of this intrinsic is [`pointer::wrapping_offset`]. |
884 | #[must_use = "returns a new pointer rather than modifying its argument" ] |
885 | #[rustc_intrinsic_const_stable_indirect] |
886 | #[rustc_nounwind ] |
887 | #[rustc_intrinsic ] |
888 | pub const unsafe fn arith_offset<T>(dst: *const T, offset: isize) -> *const T; |
889 | |
890 | /// Projects to the `index`-th element of `slice_ptr`, as the same kind of pointer |
891 | /// as the slice was provided -- so `&mut [T] → &mut T`, `&[T] → &T`, |
892 | /// `*mut [T] → *mut T`, or `*const [T] → *const T` -- without a bounds check. |
893 | /// |
894 | /// This is exposed via `<usize as SliceIndex>::get(_unchecked)(_mut)`, |
895 | /// and isn't intended to be used elsewhere. |
896 | /// |
897 | /// Expands in MIR to `{&, &mut, &raw const, &raw mut} (*slice_ptr)[index]`, |
898 | /// depending on the types involved, so no backend support is needed. |
899 | /// |
900 | /// # Safety |
901 | /// |
902 | /// - `index < PtrMetadata(slice_ptr)`, so the indexing is in-bounds for the slice |
903 | /// - the resulting offsetting is in-bounds of the allocated object, which is |
904 | /// always the case for references, but needs to be upheld manually for pointers |
905 | #[rustc_nounwind ] |
906 | #[rustc_intrinsic ] |
907 | pub const unsafe fn slice_get_unchecked< |
908 | ItemPtr: bounds::ChangePointee<[T], Pointee = T, Output = SlicePtr>, |
909 | SlicePtr, |
910 | T, |
911 | >( |
912 | slice_ptr: SlicePtr, |
913 | index: usize, |
914 | ) -> ItemPtr; |
915 | |
916 | /// Masks out bits of the pointer according to a mask. |
917 | /// |
918 | /// Note that, unlike most intrinsics, this is safe to call; |
919 | /// it does not require an `unsafe` block. |
920 | /// Therefore, implementations must not require the user to uphold |
921 | /// any safety invariants. |
922 | /// |
923 | /// Consider using [`pointer::mask`] instead. |
924 | #[rustc_nounwind ] |
925 | #[rustc_intrinsic ] |
926 | pub fn ptr_mask<T>(ptr: *const T, mask: usize) -> *const T; |
927 | |
928 | /// Equivalent to the appropriate `llvm.memcpy.p0i8.0i8.*` intrinsic, with |
929 | /// a size of `count` * `size_of::<T>()` and an alignment of |
930 | /// `min_align_of::<T>()` |
931 | /// |
932 | /// This intrinsic does not have a stable counterpart. |
933 | /// # Safety |
934 | /// |
935 | /// The safety requirements are consistent with [`copy_nonoverlapping`] |
936 | /// while the read and write behaviors are volatile, |
937 | /// which means it will not be optimized out unless `_count` or `size_of::<T>()` is equal to zero. |
938 | /// |
939 | /// [`copy_nonoverlapping`]: ptr::copy_nonoverlapping |
940 | #[rustc_intrinsic ] |
941 | #[rustc_nounwind ] |
942 | pub unsafe fn volatile_copy_nonoverlapping_memory<T>(dst: *mut T, src: *const T, count: usize); |
943 | /// Equivalent to the appropriate `llvm.memmove.p0i8.0i8.*` intrinsic, with |
944 | /// a size of `count * size_of::<T>()` and an alignment of |
945 | /// `min_align_of::<T>()` |
946 | /// |
947 | /// The volatile parameter is set to `true`, so it will not be optimized out |
948 | /// unless size is equal to zero. |
949 | /// |
950 | /// This intrinsic does not have a stable counterpart. |
951 | #[rustc_intrinsic ] |
952 | #[rustc_nounwind ] |
953 | pub unsafe fn volatile_copy_memory<T>(dst: *mut T, src: *const T, count: usize); |
954 | /// Equivalent to the appropriate `llvm.memset.p0i8.*` intrinsic, with a |
955 | /// size of `count * size_of::<T>()` and an alignment of |
956 | /// `min_align_of::<T>()`. |
957 | /// |
958 | /// This intrinsic does not have a stable counterpart. |
959 | /// # Safety |
960 | /// |
961 | /// The safety requirements are consistent with [`write_bytes`] while the write behavior is volatile, |
962 | /// which means it will not be optimized out unless `_count` or `size_of::<T>()` is equal to zero. |
963 | /// |
964 | /// [`write_bytes`]: ptr::write_bytes |
965 | #[rustc_intrinsic ] |
966 | #[rustc_nounwind ] |
967 | pub unsafe fn volatile_set_memory<T>(dst: *mut T, val: u8, count: usize); |
968 | |
969 | /// Performs a volatile load from the `src` pointer. |
970 | /// |
971 | /// The stabilized version of this intrinsic is [`core::ptr::read_volatile`]. |
972 | #[rustc_intrinsic ] |
973 | #[rustc_nounwind ] |
974 | pub unsafe fn volatile_load<T>(src: *const T) -> T; |
975 | /// Performs a volatile store to the `dst` pointer. |
976 | /// |
977 | /// The stabilized version of this intrinsic is [`core::ptr::write_volatile`]. |
978 | #[rustc_intrinsic ] |
979 | #[rustc_nounwind ] |
980 | pub unsafe fn volatile_store<T>(dst: *mut T, val: T); |
981 | |
982 | /// Performs a volatile load from the `src` pointer |
983 | /// The pointer is not required to be aligned. |
984 | /// |
985 | /// This intrinsic does not have a stable counterpart. |
986 | #[rustc_intrinsic ] |
987 | #[rustc_nounwind ] |
988 | #[rustc_diagnostic_item = "intrinsics_unaligned_volatile_load" ] |
989 | pub unsafe fn unaligned_volatile_load<T>(src: *const T) -> T; |
990 | /// Performs a volatile store to the `dst` pointer. |
991 | /// The pointer is not required to be aligned. |
992 | /// |
993 | /// This intrinsic does not have a stable counterpart. |
994 | #[rustc_intrinsic ] |
995 | #[rustc_nounwind ] |
996 | #[rustc_diagnostic_item = "intrinsics_unaligned_volatile_store" ] |
997 | pub unsafe fn unaligned_volatile_store<T>(dst: *mut T, val: T); |
998 | |
999 | /// Returns the square root of an `f16` |
1000 | /// |
1001 | /// The stabilized version of this intrinsic is |
1002 | /// [`f16::sqrt`](../../std/primitive.f16.html#method.sqrt) |
1003 | #[rustc_intrinsic ] |
1004 | #[rustc_nounwind ] |
1005 | pub unsafe fn sqrtf16(x: f16) -> f16; |
1006 | /// Returns the square root of an `f32` |
1007 | /// |
1008 | /// The stabilized version of this intrinsic is |
1009 | /// [`f32::sqrt`](../../std/primitive.f32.html#method.sqrt) |
1010 | #[rustc_intrinsic ] |
1011 | #[rustc_nounwind ] |
1012 | pub unsafe fn sqrtf32(x: f32) -> f32; |
1013 | /// Returns the square root of an `f64` |
1014 | /// |
1015 | /// The stabilized version of this intrinsic is |
1016 | /// [`f64::sqrt`](../../std/primitive.f64.html#method.sqrt) |
1017 | #[rustc_intrinsic ] |
1018 | #[rustc_nounwind ] |
1019 | pub unsafe fn sqrtf64(x: f64) -> f64; |
1020 | /// Returns the square root of an `f128` |
1021 | /// |
1022 | /// The stabilized version of this intrinsic is |
1023 | /// [`f128::sqrt`](../../std/primitive.f128.html#method.sqrt) |
1024 | #[rustc_intrinsic ] |
1025 | #[rustc_nounwind ] |
1026 | pub unsafe fn sqrtf128(x: f128) -> f128; |
1027 | |
1028 | /// Raises an `f16` to an integer power. |
1029 | /// |
1030 | /// The stabilized version of this intrinsic is |
1031 | /// [`f16::powi`](../../std/primitive.f16.html#method.powi) |
1032 | #[rustc_intrinsic ] |
1033 | #[rustc_nounwind ] |
1034 | pub unsafe fn powif16(a: f16, x: i32) -> f16; |
1035 | /// Raises an `f32` to an integer power. |
1036 | /// |
1037 | /// The stabilized version of this intrinsic is |
1038 | /// [`f32::powi`](../../std/primitive.f32.html#method.powi) |
1039 | #[rustc_intrinsic ] |
1040 | #[rustc_nounwind ] |
1041 | pub unsafe fn powif32(a: f32, x: i32) -> f32; |
1042 | /// Raises an `f64` to an integer power. |
1043 | /// |
1044 | /// The stabilized version of this intrinsic is |
1045 | /// [`f64::powi`](../../std/primitive.f64.html#method.powi) |
1046 | #[rustc_intrinsic ] |
1047 | #[rustc_nounwind ] |
1048 | pub unsafe fn powif64(a: f64, x: i32) -> f64; |
1049 | /// Raises an `f128` to an integer power. |
1050 | /// |
1051 | /// The stabilized version of this intrinsic is |
1052 | /// [`f128::powi`](../../std/primitive.f128.html#method.powi) |
1053 | #[rustc_intrinsic ] |
1054 | #[rustc_nounwind ] |
1055 | pub unsafe fn powif128(a: f128, x: i32) -> f128; |
1056 | |
1057 | /// Returns the sine of an `f16`. |
1058 | /// |
1059 | /// The stabilized version of this intrinsic is |
1060 | /// [`f16::sin`](../../std/primitive.f16.html#method.sin) |
1061 | #[rustc_intrinsic ] |
1062 | #[rustc_nounwind ] |
1063 | pub unsafe fn sinf16(x: f16) -> f16; |
1064 | /// Returns the sine of an `f32`. |
1065 | /// |
1066 | /// The stabilized version of this intrinsic is |
1067 | /// [`f32::sin`](../../std/primitive.f32.html#method.sin) |
1068 | #[rustc_intrinsic ] |
1069 | #[rustc_nounwind ] |
1070 | pub unsafe fn sinf32(x: f32) -> f32; |
1071 | /// Returns the sine of an `f64`. |
1072 | /// |
1073 | /// The stabilized version of this intrinsic is |
1074 | /// [`f64::sin`](../../std/primitive.f64.html#method.sin) |
1075 | #[rustc_intrinsic ] |
1076 | #[rustc_nounwind ] |
1077 | pub unsafe fn sinf64(x: f64) -> f64; |
1078 | /// Returns the sine of an `f128`. |
1079 | /// |
1080 | /// The stabilized version of this intrinsic is |
1081 | /// [`f128::sin`](../../std/primitive.f128.html#method.sin) |
1082 | #[rustc_intrinsic ] |
1083 | #[rustc_nounwind ] |
1084 | pub unsafe fn sinf128(x: f128) -> f128; |
1085 | |
1086 | /// Returns the cosine of an `f16`. |
1087 | /// |
1088 | /// The stabilized version of this intrinsic is |
1089 | /// [`f16::cos`](../../std/primitive.f16.html#method.cos) |
1090 | #[rustc_intrinsic ] |
1091 | #[rustc_nounwind ] |
1092 | pub unsafe fn cosf16(x: f16) -> f16; |
1093 | /// Returns the cosine of an `f32`. |
1094 | /// |
1095 | /// The stabilized version of this intrinsic is |
1096 | /// [`f32::cos`](../../std/primitive.f32.html#method.cos) |
1097 | #[rustc_intrinsic ] |
1098 | #[rustc_nounwind ] |
1099 | pub unsafe fn cosf32(x: f32) -> f32; |
1100 | /// Returns the cosine of an `f64`. |
1101 | /// |
1102 | /// The stabilized version of this intrinsic is |
1103 | /// [`f64::cos`](../../std/primitive.f64.html#method.cos) |
1104 | #[rustc_intrinsic ] |
1105 | #[rustc_nounwind ] |
1106 | pub unsafe fn cosf64(x: f64) -> f64; |
1107 | /// Returns the cosine of an `f128`. |
1108 | /// |
1109 | /// The stabilized version of this intrinsic is |
1110 | /// [`f128::cos`](../../std/primitive.f128.html#method.cos) |
1111 | #[rustc_intrinsic ] |
1112 | #[rustc_nounwind ] |
1113 | pub unsafe fn cosf128(x: f128) -> f128; |
1114 | |
1115 | /// Raises an `f16` to an `f16` power. |
1116 | /// |
1117 | /// The stabilized version of this intrinsic is |
1118 | /// [`f16::powf`](../../std/primitive.f16.html#method.powf) |
1119 | #[rustc_intrinsic ] |
1120 | #[rustc_nounwind ] |
1121 | pub unsafe fn powf16(a: f16, x: f16) -> f16; |
1122 | /// Raises an `f32` to an `f32` power. |
1123 | /// |
1124 | /// The stabilized version of this intrinsic is |
1125 | /// [`f32::powf`](../../std/primitive.f32.html#method.powf) |
1126 | #[rustc_intrinsic ] |
1127 | #[rustc_nounwind ] |
1128 | pub unsafe fn powf32(a: f32, x: f32) -> f32; |
1129 | /// Raises an `f64` to an `f64` power. |
1130 | /// |
1131 | /// The stabilized version of this intrinsic is |
1132 | /// [`f64::powf`](../../std/primitive.f64.html#method.powf) |
1133 | #[rustc_intrinsic ] |
1134 | #[rustc_nounwind ] |
1135 | pub unsafe fn powf64(a: f64, x: f64) -> f64; |
1136 | /// Raises an `f128` to an `f128` power. |
1137 | /// |
1138 | /// The stabilized version of this intrinsic is |
1139 | /// [`f128::powf`](../../std/primitive.f128.html#method.powf) |
1140 | #[rustc_intrinsic ] |
1141 | #[rustc_nounwind ] |
1142 | pub unsafe fn powf128(a: f128, x: f128) -> f128; |
1143 | |
1144 | /// Returns the exponential of an `f16`. |
1145 | /// |
1146 | /// The stabilized version of this intrinsic is |
1147 | /// [`f16::exp`](../../std/primitive.f16.html#method.exp) |
1148 | #[rustc_intrinsic ] |
1149 | #[rustc_nounwind ] |
1150 | pub unsafe fn expf16(x: f16) -> f16; |
1151 | /// Returns the exponential of an `f32`. |
1152 | /// |
1153 | /// The stabilized version of this intrinsic is |
1154 | /// [`f32::exp`](../../std/primitive.f32.html#method.exp) |
1155 | #[rustc_intrinsic ] |
1156 | #[rustc_nounwind ] |
1157 | pub unsafe fn expf32(x: f32) -> f32; |
1158 | /// Returns the exponential of an `f64`. |
1159 | /// |
1160 | /// The stabilized version of this intrinsic is |
1161 | /// [`f64::exp`](../../std/primitive.f64.html#method.exp) |
1162 | #[rustc_intrinsic ] |
1163 | #[rustc_nounwind ] |
1164 | pub unsafe fn expf64(x: f64) -> f64; |
1165 | /// Returns the exponential of an `f128`. |
1166 | /// |
1167 | /// The stabilized version of this intrinsic is |
1168 | /// [`f128::exp`](../../std/primitive.f128.html#method.exp) |
1169 | #[rustc_intrinsic ] |
1170 | #[rustc_nounwind ] |
1171 | pub unsafe fn expf128(x: f128) -> f128; |
1172 | |
1173 | /// Returns 2 raised to the power of an `f16`. |
1174 | /// |
1175 | /// The stabilized version of this intrinsic is |
1176 | /// [`f16::exp2`](../../std/primitive.f16.html#method.exp2) |
1177 | #[rustc_intrinsic ] |
1178 | #[rustc_nounwind ] |
1179 | pub unsafe fn exp2f16(x: f16) -> f16; |
1180 | /// Returns 2 raised to the power of an `f32`. |
1181 | /// |
1182 | /// The stabilized version of this intrinsic is |
1183 | /// [`f32::exp2`](../../std/primitive.f32.html#method.exp2) |
1184 | #[rustc_intrinsic ] |
1185 | #[rustc_nounwind ] |
1186 | pub unsafe fn exp2f32(x: f32) -> f32; |
1187 | /// Returns 2 raised to the power of an `f64`. |
1188 | /// |
1189 | /// The stabilized version of this intrinsic is |
1190 | /// [`f64::exp2`](../../std/primitive.f64.html#method.exp2) |
1191 | #[rustc_intrinsic ] |
1192 | #[rustc_nounwind ] |
1193 | pub unsafe fn exp2f64(x: f64) -> f64; |
1194 | /// Returns 2 raised to the power of an `f128`. |
1195 | /// |
1196 | /// The stabilized version of this intrinsic is |
1197 | /// [`f128::exp2`](../../std/primitive.f128.html#method.exp2) |
1198 | #[rustc_intrinsic ] |
1199 | #[rustc_nounwind ] |
1200 | pub unsafe fn exp2f128(x: f128) -> f128; |
1201 | |
1202 | /// Returns the natural logarithm of an `f16`. |
1203 | /// |
1204 | /// The stabilized version of this intrinsic is |
1205 | /// [`f16::ln`](../../std/primitive.f16.html#method.ln) |
1206 | #[rustc_intrinsic ] |
1207 | #[rustc_nounwind ] |
1208 | pub unsafe fn logf16(x: f16) -> f16; |
1209 | /// Returns the natural logarithm of an `f32`. |
1210 | /// |
1211 | /// The stabilized version of this intrinsic is |
1212 | /// [`f32::ln`](../../std/primitive.f32.html#method.ln) |
1213 | #[rustc_intrinsic ] |
1214 | #[rustc_nounwind ] |
1215 | pub unsafe fn logf32(x: f32) -> f32; |
1216 | /// Returns the natural logarithm of an `f64`. |
1217 | /// |
1218 | /// The stabilized version of this intrinsic is |
1219 | /// [`f64::ln`](../../std/primitive.f64.html#method.ln) |
1220 | #[rustc_intrinsic ] |
1221 | #[rustc_nounwind ] |
1222 | pub unsafe fn logf64(x: f64) -> f64; |
1223 | /// Returns the natural logarithm of an `f128`. |
1224 | /// |
1225 | /// The stabilized version of this intrinsic is |
1226 | /// [`f128::ln`](../../std/primitive.f128.html#method.ln) |
1227 | #[rustc_intrinsic ] |
1228 | #[rustc_nounwind ] |
1229 | pub unsafe fn logf128(x: f128) -> f128; |
1230 | |
1231 | /// Returns the base 10 logarithm of an `f16`. |
1232 | /// |
1233 | /// The stabilized version of this intrinsic is |
1234 | /// [`f16::log10`](../../std/primitive.f16.html#method.log10) |
1235 | #[rustc_intrinsic ] |
1236 | #[rustc_nounwind ] |
1237 | pub unsafe fn log10f16(x: f16) -> f16; |
1238 | /// Returns the base 10 logarithm of an `f32`. |
1239 | /// |
1240 | /// The stabilized version of this intrinsic is |
1241 | /// [`f32::log10`](../../std/primitive.f32.html#method.log10) |
1242 | #[rustc_intrinsic ] |
1243 | #[rustc_nounwind ] |
1244 | pub unsafe fn log10f32(x: f32) -> f32; |
1245 | /// Returns the base 10 logarithm of an `f64`. |
1246 | /// |
1247 | /// The stabilized version of this intrinsic is |
1248 | /// [`f64::log10`](../../std/primitive.f64.html#method.log10) |
1249 | #[rustc_intrinsic ] |
1250 | #[rustc_nounwind ] |
1251 | pub unsafe fn log10f64(x: f64) -> f64; |
1252 | /// Returns the base 10 logarithm of an `f128`. |
1253 | /// |
1254 | /// The stabilized version of this intrinsic is |
1255 | /// [`f128::log10`](../../std/primitive.f128.html#method.log10) |
1256 | #[rustc_intrinsic ] |
1257 | #[rustc_nounwind ] |
1258 | pub unsafe fn log10f128(x: f128) -> f128; |
1259 | |
1260 | /// Returns the base 2 logarithm of an `f16`. |
1261 | /// |
1262 | /// The stabilized version of this intrinsic is |
1263 | /// [`f16::log2`](../../std/primitive.f16.html#method.log2) |
1264 | #[rustc_intrinsic ] |
1265 | #[rustc_nounwind ] |
1266 | pub unsafe fn log2f16(x: f16) -> f16; |
1267 | /// Returns the base 2 logarithm of an `f32`. |
1268 | /// |
1269 | /// The stabilized version of this intrinsic is |
1270 | /// [`f32::log2`](../../std/primitive.f32.html#method.log2) |
1271 | #[rustc_intrinsic ] |
1272 | #[rustc_nounwind ] |
1273 | pub unsafe fn log2f32(x: f32) -> f32; |
1274 | /// Returns the base 2 logarithm of an `f64`. |
1275 | /// |
1276 | /// The stabilized version of this intrinsic is |
1277 | /// [`f64::log2`](../../std/primitive.f64.html#method.log2) |
1278 | #[rustc_intrinsic ] |
1279 | #[rustc_nounwind ] |
1280 | pub unsafe fn log2f64(x: f64) -> f64; |
1281 | /// Returns the base 2 logarithm of an `f128`. |
1282 | /// |
1283 | /// The stabilized version of this intrinsic is |
1284 | /// [`f128::log2`](../../std/primitive.f128.html#method.log2) |
1285 | #[rustc_intrinsic ] |
1286 | #[rustc_nounwind ] |
1287 | pub unsafe fn log2f128(x: f128) -> f128; |
1288 | |
1289 | /// Returns `a * b + c` for `f16` values. |
1290 | /// |
1291 | /// The stabilized version of this intrinsic is |
1292 | /// [`f16::mul_add`](../../std/primitive.f16.html#method.mul_add) |
1293 | #[rustc_intrinsic ] |
1294 | #[rustc_nounwind ] |
1295 | pub unsafe fn fmaf16(a: f16, b: f16, c: f16) -> f16; |
1296 | /// Returns `a * b + c` for `f32` values. |
1297 | /// |
1298 | /// The stabilized version of this intrinsic is |
1299 | /// [`f32::mul_add`](../../std/primitive.f32.html#method.mul_add) |
1300 | #[rustc_intrinsic ] |
1301 | #[rustc_nounwind ] |
1302 | pub unsafe fn fmaf32(a: f32, b: f32, c: f32) -> f32; |
1303 | /// Returns `a * b + c` for `f64` values. |
1304 | /// |
1305 | /// The stabilized version of this intrinsic is |
1306 | /// [`f64::mul_add`](../../std/primitive.f64.html#method.mul_add) |
1307 | #[rustc_intrinsic ] |
1308 | #[rustc_nounwind ] |
1309 | pub unsafe fn fmaf64(a: f64, b: f64, c: f64) -> f64; |
1310 | /// Returns `a * b + c` for `f128` values. |
1311 | /// |
1312 | /// The stabilized version of this intrinsic is |
1313 | /// [`f128::mul_add`](../../std/primitive.f128.html#method.mul_add) |
1314 | #[rustc_intrinsic ] |
1315 | #[rustc_nounwind ] |
1316 | pub unsafe fn fmaf128(a: f128, b: f128, c: f128) -> f128; |
1317 | |
1318 | /// Returns `a * b + c` for `f16` values, non-deterministically executing |
1319 | /// either a fused multiply-add or two operations with rounding of the |
1320 | /// intermediate result. |
1321 | /// |
1322 | /// The operation is fused if the code generator determines that target |
1323 | /// instruction set has support for a fused operation, and that the fused |
1324 | /// operation is more efficient than the equivalent, separate pair of mul |
1325 | /// and add instructions. It is unspecified whether or not a fused operation |
1326 | /// is selected, and that may depend on optimization level and context, for |
1327 | /// example. |
1328 | #[rustc_intrinsic ] |
1329 | #[rustc_nounwind ] |
1330 | pub unsafe fn fmuladdf16(a: f16, b: f16, c: f16) -> f16; |
1331 | /// Returns `a * b + c` for `f32` values, non-deterministically executing |
1332 | /// either a fused multiply-add or two operations with rounding of the |
1333 | /// intermediate result. |
1334 | /// |
1335 | /// The operation is fused if the code generator determines that target |
1336 | /// instruction set has support for a fused operation, and that the fused |
1337 | /// operation is more efficient than the equivalent, separate pair of mul |
1338 | /// and add instructions. It is unspecified whether or not a fused operation |
1339 | /// is selected, and that may depend on optimization level and context, for |
1340 | /// example. |
1341 | #[rustc_intrinsic ] |
1342 | #[rustc_nounwind ] |
1343 | pub unsafe fn fmuladdf32(a: f32, b: f32, c: f32) -> f32; |
1344 | /// Returns `a * b + c` for `f64` values, non-deterministically executing |
1345 | /// either a fused multiply-add or two operations with rounding of the |
1346 | /// intermediate result. |
1347 | /// |
1348 | /// The operation is fused if the code generator determines that target |
1349 | /// instruction set has support for a fused operation, and that the fused |
1350 | /// operation is more efficient than the equivalent, separate pair of mul |
1351 | /// and add instructions. It is unspecified whether or not a fused operation |
1352 | /// is selected, and that may depend on optimization level and context, for |
1353 | /// example. |
1354 | #[rustc_intrinsic ] |
1355 | #[rustc_nounwind ] |
1356 | pub unsafe fn fmuladdf64(a: f64, b: f64, c: f64) -> f64; |
1357 | /// Returns `a * b + c` for `f128` values, non-deterministically executing |
1358 | /// either a fused multiply-add or two operations with rounding of the |
1359 | /// intermediate result. |
1360 | /// |
1361 | /// The operation is fused if the code generator determines that target |
1362 | /// instruction set has support for a fused operation, and that the fused |
1363 | /// operation is more efficient than the equivalent, separate pair of mul |
1364 | /// and add instructions. It is unspecified whether or not a fused operation |
1365 | /// is selected, and that may depend on optimization level and context, for |
1366 | /// example. |
1367 | #[rustc_intrinsic ] |
1368 | #[rustc_nounwind ] |
1369 | pub unsafe fn fmuladdf128(a: f128, b: f128, c: f128) -> f128; |
1370 | |
1371 | /// Returns the largest integer less than or equal to an `f16`. |
1372 | /// |
1373 | /// The stabilized version of this intrinsic is |
1374 | /// [`f16::floor`](../../std/primitive.f16.html#method.floor) |
1375 | #[rustc_intrinsic ] |
1376 | #[rustc_nounwind ] |
1377 | pub const unsafe fn floorf16(x: f16) -> f16; |
1378 | /// Returns the largest integer less than or equal to an `f32`. |
1379 | /// |
1380 | /// The stabilized version of this intrinsic is |
1381 | /// [`f32::floor`](../../std/primitive.f32.html#method.floor) |
1382 | #[rustc_intrinsic ] |
1383 | #[rustc_nounwind ] |
1384 | pub const unsafe fn floorf32(x: f32) -> f32; |
1385 | /// Returns the largest integer less than or equal to an `f64`. |
1386 | /// |
1387 | /// The stabilized version of this intrinsic is |
1388 | /// [`f64::floor`](../../std/primitive.f64.html#method.floor) |
1389 | #[rustc_intrinsic ] |
1390 | #[rustc_nounwind ] |
1391 | pub const unsafe fn floorf64(x: f64) -> f64; |
1392 | /// Returns the largest integer less than or equal to an `f128`. |
1393 | /// |
1394 | /// The stabilized version of this intrinsic is |
1395 | /// [`f128::floor`](../../std/primitive.f128.html#method.floor) |
1396 | #[rustc_intrinsic ] |
1397 | #[rustc_nounwind ] |
1398 | pub const unsafe fn floorf128(x: f128) -> f128; |
1399 | |
1400 | /// Returns the smallest integer greater than or equal to an `f16`. |
1401 | /// |
1402 | /// The stabilized version of this intrinsic is |
1403 | /// [`f16::ceil`](../../std/primitive.f16.html#method.ceil) |
1404 | #[rustc_intrinsic ] |
1405 | #[rustc_nounwind ] |
1406 | pub const unsafe fn ceilf16(x: f16) -> f16; |
1407 | /// Returns the smallest integer greater than or equal to an `f32`. |
1408 | /// |
1409 | /// The stabilized version of this intrinsic is |
1410 | /// [`f32::ceil`](../../std/primitive.f32.html#method.ceil) |
1411 | #[rustc_intrinsic ] |
1412 | #[rustc_nounwind ] |
1413 | pub const unsafe fn ceilf32(x: f32) -> f32; |
1414 | /// Returns the smallest integer greater than or equal to an `f64`. |
1415 | /// |
1416 | /// The stabilized version of this intrinsic is |
1417 | /// [`f64::ceil`](../../std/primitive.f64.html#method.ceil) |
1418 | #[rustc_intrinsic ] |
1419 | #[rustc_nounwind ] |
1420 | pub const unsafe fn ceilf64(x: f64) -> f64; |
1421 | /// Returns the smallest integer greater than or equal to an `f128`. |
1422 | /// |
1423 | /// The stabilized version of this intrinsic is |
1424 | /// [`f128::ceil`](../../std/primitive.f128.html#method.ceil) |
1425 | #[rustc_intrinsic ] |
1426 | #[rustc_nounwind ] |
1427 | pub const unsafe fn ceilf128(x: f128) -> f128; |
1428 | |
1429 | /// Returns the integer part of an `f16`. |
1430 | /// |
1431 | /// The stabilized version of this intrinsic is |
1432 | /// [`f16::trunc`](../../std/primitive.f16.html#method.trunc) |
1433 | #[rustc_intrinsic ] |
1434 | #[rustc_nounwind ] |
1435 | pub const unsafe fn truncf16(x: f16) -> f16; |
1436 | /// Returns the integer part of an `f32`. |
1437 | /// |
1438 | /// The stabilized version of this intrinsic is |
1439 | /// [`f32::trunc`](../../std/primitive.f32.html#method.trunc) |
1440 | #[rustc_intrinsic ] |
1441 | #[rustc_nounwind ] |
1442 | pub const unsafe fn truncf32(x: f32) -> f32; |
1443 | /// Returns the integer part of an `f64`. |
1444 | /// |
1445 | /// The stabilized version of this intrinsic is |
1446 | /// [`f64::trunc`](../../std/primitive.f64.html#method.trunc) |
1447 | #[rustc_intrinsic ] |
1448 | #[rustc_nounwind ] |
1449 | pub const unsafe fn truncf64(x: f64) -> f64; |
1450 | /// Returns the integer part of an `f128`. |
1451 | /// |
1452 | /// The stabilized version of this intrinsic is |
1453 | /// [`f128::trunc`](../../std/primitive.f128.html#method.trunc) |
1454 | #[rustc_intrinsic ] |
1455 | #[rustc_nounwind ] |
1456 | pub const unsafe fn truncf128(x: f128) -> f128; |
1457 | |
1458 | /// Returns the nearest integer to an `f16`. Rounds half-way cases to the number with an even |
1459 | /// least significant digit. |
1460 | /// |
1461 | /// The stabilized version of this intrinsic is |
1462 | /// [`f16::round_ties_even`](../../std/primitive.f16.html#method.round_ties_even) |
1463 | #[rustc_intrinsic ] |
1464 | #[rustc_nounwind ] |
1465 | pub const fn round_ties_even_f16(x: f16) -> f16; |
1466 | |
1467 | /// Returns the nearest integer to an `f32`. Rounds half-way cases to the number with an even |
1468 | /// least significant digit. |
1469 | /// |
1470 | /// The stabilized version of this intrinsic is |
1471 | /// [`f32::round_ties_even`](../../std/primitive.f32.html#method.round_ties_even) |
1472 | #[rustc_intrinsic ] |
1473 | #[rustc_nounwind ] |
1474 | pub const fn round_ties_even_f32(x: f32) -> f32; |
1475 | |
1476 | /// Returns the nearest integer to an `f64`. Rounds half-way cases to the number with an even |
1477 | /// least significant digit. |
1478 | /// |
1479 | /// The stabilized version of this intrinsic is |
1480 | /// [`f64::round_ties_even`](../../std/primitive.f64.html#method.round_ties_even) |
1481 | #[rustc_intrinsic ] |
1482 | #[rustc_nounwind ] |
1483 | pub const fn round_ties_even_f64(x: f64) -> f64; |
1484 | |
1485 | /// Returns the nearest integer to an `f128`. Rounds half-way cases to the number with an even |
1486 | /// least significant digit. |
1487 | /// |
1488 | /// The stabilized version of this intrinsic is |
1489 | /// [`f128::round_ties_even`](../../std/primitive.f128.html#method.round_ties_even) |
1490 | #[rustc_intrinsic ] |
1491 | #[rustc_nounwind ] |
1492 | pub const fn round_ties_even_f128(x: f128) -> f128; |
1493 | |
1494 | /// Returns the nearest integer to an `f16`. Rounds half-way cases away from zero. |
1495 | /// |
1496 | /// The stabilized version of this intrinsic is |
1497 | /// [`f16::round`](../../std/primitive.f16.html#method.round) |
1498 | #[rustc_intrinsic ] |
1499 | #[rustc_nounwind ] |
1500 | pub const unsafe fn roundf16(x: f16) -> f16; |
1501 | /// Returns the nearest integer to an `f32`. Rounds half-way cases away from zero. |
1502 | /// |
1503 | /// The stabilized version of this intrinsic is |
1504 | /// [`f32::round`](../../std/primitive.f32.html#method.round) |
1505 | #[rustc_intrinsic ] |
1506 | #[rustc_nounwind ] |
1507 | pub const unsafe fn roundf32(x: f32) -> f32; |
1508 | /// Returns the nearest integer to an `f64`. Rounds half-way cases away from zero. |
1509 | /// |
1510 | /// The stabilized version of this intrinsic is |
1511 | /// [`f64::round`](../../std/primitive.f64.html#method.round) |
1512 | #[rustc_intrinsic ] |
1513 | #[rustc_nounwind ] |
1514 | pub const unsafe fn roundf64(x: f64) -> f64; |
1515 | /// Returns the nearest integer to an `f128`. Rounds half-way cases away from zero. |
1516 | /// |
1517 | /// The stabilized version of this intrinsic is |
1518 | /// [`f128::round`](../../std/primitive.f128.html#method.round) |
1519 | #[rustc_intrinsic ] |
1520 | #[rustc_nounwind ] |
1521 | pub const unsafe fn roundf128(x: f128) -> f128; |
1522 | |
1523 | /// Float addition that allows optimizations based on algebraic rules. |
1524 | /// May assume inputs are finite. |
1525 | /// |
1526 | /// This intrinsic does not have a stable counterpart. |
1527 | #[rustc_intrinsic ] |
1528 | #[rustc_nounwind ] |
1529 | pub unsafe fn fadd_fast<T: Copy>(a: T, b: T) -> T; |
1530 | |
1531 | /// Float subtraction that allows optimizations based on algebraic rules. |
1532 | /// May assume inputs are finite. |
1533 | /// |
1534 | /// This intrinsic does not have a stable counterpart. |
1535 | #[rustc_intrinsic ] |
1536 | #[rustc_nounwind ] |
1537 | pub unsafe fn fsub_fast<T: Copy>(a: T, b: T) -> T; |
1538 | |
1539 | /// Float multiplication that allows optimizations based on algebraic rules. |
1540 | /// May assume inputs are finite. |
1541 | /// |
1542 | /// This intrinsic does not have a stable counterpart. |
1543 | #[rustc_intrinsic ] |
1544 | #[rustc_nounwind ] |
1545 | pub unsafe fn fmul_fast<T: Copy>(a: T, b: T) -> T; |
1546 | |
1547 | /// Float division that allows optimizations based on algebraic rules. |
1548 | /// May assume inputs are finite. |
1549 | /// |
1550 | /// This intrinsic does not have a stable counterpart. |
1551 | #[rustc_intrinsic ] |
1552 | #[rustc_nounwind ] |
1553 | pub unsafe fn fdiv_fast<T: Copy>(a: T, b: T) -> T; |
1554 | |
1555 | /// Float remainder that allows optimizations based on algebraic rules. |
1556 | /// May assume inputs are finite. |
1557 | /// |
1558 | /// This intrinsic does not have a stable counterpart. |
1559 | #[rustc_intrinsic ] |
1560 | #[rustc_nounwind ] |
1561 | pub unsafe fn frem_fast<T: Copy>(a: T, b: T) -> T; |
1562 | |
1563 | /// Converts with LLVM’s fptoui/fptosi, which may return undef for values out of range |
1564 | /// (<https://github.com/rust-lang/rust/issues/10184>) |
1565 | /// |
1566 | /// Stabilized as [`f32::to_int_unchecked`] and [`f64::to_int_unchecked`]. |
1567 | #[rustc_intrinsic ] |
1568 | #[rustc_nounwind ] |
1569 | pub unsafe fn float_to_int_unchecked<Float: Copy, Int: Copy>(value: Float) -> Int; |
1570 | |
1571 | /// Float addition that allows optimizations based on algebraic rules. |
1572 | /// |
1573 | /// Stabilized as [`f16::algebraic_add`], [`f32::algebraic_add`], [`f64::algebraic_add`] and [`f128::algebraic_add`]. |
1574 | #[rustc_nounwind ] |
1575 | #[rustc_intrinsic ] |
1576 | pub const fn fadd_algebraic<T: Copy>(a: T, b: T) -> T; |
1577 | |
1578 | /// Float subtraction that allows optimizations based on algebraic rules. |
1579 | /// |
1580 | /// Stabilized as [`f16::algebraic_sub`], [`f32::algebraic_sub`], [`f64::algebraic_sub`] and [`f128::algebraic_sub`]. |
1581 | #[rustc_nounwind ] |
1582 | #[rustc_intrinsic ] |
1583 | pub const fn fsub_algebraic<T: Copy>(a: T, b: T) -> T; |
1584 | |
1585 | /// Float multiplication that allows optimizations based on algebraic rules. |
1586 | /// |
1587 | /// Stabilized as [`f16::algebraic_mul`], [`f32::algebraic_mul`], [`f64::algebraic_mul`] and [`f128::algebraic_mul`]. |
1588 | #[rustc_nounwind ] |
1589 | #[rustc_intrinsic ] |
1590 | pub const fn fmul_algebraic<T: Copy>(a: T, b: T) -> T; |
1591 | |
1592 | /// Float division that allows optimizations based on algebraic rules. |
1593 | /// |
1594 | /// Stabilized as [`f16::algebraic_div`], [`f32::algebraic_div`], [`f64::algebraic_div`] and [`f128::algebraic_div`]. |
1595 | #[rustc_nounwind ] |
1596 | #[rustc_intrinsic ] |
1597 | pub const fn fdiv_algebraic<T: Copy>(a: T, b: T) -> T; |
1598 | |
1599 | /// Float remainder that allows optimizations based on algebraic rules. |
1600 | /// |
1601 | /// Stabilized as [`f16::algebraic_rem`], [`f32::algebraic_rem`], [`f64::algebraic_rem`] and [`f128::algebraic_rem`]. |
1602 | #[rustc_nounwind ] |
1603 | #[rustc_intrinsic ] |
1604 | pub const fn frem_algebraic<T: Copy>(a: T, b: T) -> T; |
1605 | |
1606 | /// Returns the number of bits set in an integer type `T` |
1607 | /// |
1608 | /// Note that, unlike most intrinsics, this is safe to call; |
1609 | /// it does not require an `unsafe` block. |
1610 | /// Therefore, implementations must not require the user to uphold |
1611 | /// any safety invariants. |
1612 | /// |
1613 | /// The stabilized versions of this intrinsic are available on the integer |
1614 | /// primitives via the `count_ones` method. For example, |
1615 | /// [`u32::count_ones`] |
1616 | #[rustc_intrinsic_const_stable_indirect] |
1617 | #[rustc_nounwind ] |
1618 | #[rustc_intrinsic ] |
1619 | pub const fn ctpop<T: Copy>(x: T) -> u32; |
1620 | |
1621 | /// Returns the number of leading unset bits (zeroes) in an integer type `T`. |
1622 | /// |
1623 | /// Note that, unlike most intrinsics, this is safe to call; |
1624 | /// it does not require an `unsafe` block. |
1625 | /// Therefore, implementations must not require the user to uphold |
1626 | /// any safety invariants. |
1627 | /// |
1628 | /// The stabilized versions of this intrinsic are available on the integer |
1629 | /// primitives via the `leading_zeros` method. For example, |
1630 | /// [`u32::leading_zeros`] |
1631 | /// |
1632 | /// # Examples |
1633 | /// |
1634 | /// ``` |
1635 | /// #![feature(core_intrinsics)] |
1636 | /// # #![allow(internal_features)] |
1637 | /// |
1638 | /// use std::intrinsics::ctlz; |
1639 | /// |
1640 | /// let x = 0b0001_1100_u8; |
1641 | /// let num_leading = ctlz(x); |
1642 | /// assert_eq!(num_leading, 3); |
1643 | /// ``` |
1644 | /// |
1645 | /// An `x` with value `0` will return the bit width of `T`. |
1646 | /// |
1647 | /// ``` |
1648 | /// #![feature(core_intrinsics)] |
1649 | /// # #![allow(internal_features)] |
1650 | /// |
1651 | /// use std::intrinsics::ctlz; |
1652 | /// |
1653 | /// let x = 0u16; |
1654 | /// let num_leading = ctlz(x); |
1655 | /// assert_eq!(num_leading, 16); |
1656 | /// ``` |
1657 | #[rustc_intrinsic_const_stable_indirect] |
1658 | #[rustc_nounwind ] |
1659 | #[rustc_intrinsic ] |
1660 | pub const fn ctlz<T: Copy>(x: T) -> u32; |
1661 | |
1662 | /// Like `ctlz`, but extra-unsafe as it returns `undef` when |
1663 | /// given an `x` with value `0`. |
1664 | /// |
1665 | /// This intrinsic does not have a stable counterpart. |
1666 | /// |
1667 | /// # Examples |
1668 | /// |
1669 | /// ``` |
1670 | /// #![feature(core_intrinsics)] |
1671 | /// # #![allow(internal_features)] |
1672 | /// |
1673 | /// use std::intrinsics::ctlz_nonzero; |
1674 | /// |
1675 | /// let x = 0b0001_1100_u8; |
1676 | /// let num_leading = unsafe { ctlz_nonzero(x) }; |
1677 | /// assert_eq!(num_leading, 3); |
1678 | /// ``` |
1679 | #[rustc_intrinsic_const_stable_indirect] |
1680 | #[rustc_nounwind ] |
1681 | #[rustc_intrinsic ] |
1682 | pub const unsafe fn ctlz_nonzero<T: Copy>(x: T) -> u32; |
1683 | |
1684 | /// Returns the number of trailing unset bits (zeroes) in an integer type `T`. |
1685 | /// |
1686 | /// Note that, unlike most intrinsics, this is safe to call; |
1687 | /// it does not require an `unsafe` block. |
1688 | /// Therefore, implementations must not require the user to uphold |
1689 | /// any safety invariants. |
1690 | /// |
1691 | /// The stabilized versions of this intrinsic are available on the integer |
1692 | /// primitives via the `trailing_zeros` method. For example, |
1693 | /// [`u32::trailing_zeros`] |
1694 | /// |
1695 | /// # Examples |
1696 | /// |
1697 | /// ``` |
1698 | /// #![feature(core_intrinsics)] |
1699 | /// # #![allow(internal_features)] |
1700 | /// |
1701 | /// use std::intrinsics::cttz; |
1702 | /// |
1703 | /// let x = 0b0011_1000_u8; |
1704 | /// let num_trailing = cttz(x); |
1705 | /// assert_eq!(num_trailing, 3); |
1706 | /// ``` |
1707 | /// |
1708 | /// An `x` with value `0` will return the bit width of `T`: |
1709 | /// |
1710 | /// ``` |
1711 | /// #![feature(core_intrinsics)] |
1712 | /// # #![allow(internal_features)] |
1713 | /// |
1714 | /// use std::intrinsics::cttz; |
1715 | /// |
1716 | /// let x = 0u16; |
1717 | /// let num_trailing = cttz(x); |
1718 | /// assert_eq!(num_trailing, 16); |
1719 | /// ``` |
1720 | #[rustc_intrinsic_const_stable_indirect] |
1721 | #[rustc_nounwind ] |
1722 | #[rustc_intrinsic ] |
1723 | pub const fn cttz<T: Copy>(x: T) -> u32; |
1724 | |
1725 | /// Like `cttz`, but extra-unsafe as it returns `undef` when |
1726 | /// given an `x` with value `0`. |
1727 | /// |
1728 | /// This intrinsic does not have a stable counterpart. |
1729 | /// |
1730 | /// # Examples |
1731 | /// |
1732 | /// ``` |
1733 | /// #![feature(core_intrinsics)] |
1734 | /// # #![allow(internal_features)] |
1735 | /// |
1736 | /// use std::intrinsics::cttz_nonzero; |
1737 | /// |
1738 | /// let x = 0b0011_1000_u8; |
1739 | /// let num_trailing = unsafe { cttz_nonzero(x) }; |
1740 | /// assert_eq!(num_trailing, 3); |
1741 | /// ``` |
1742 | #[rustc_intrinsic_const_stable_indirect] |
1743 | #[rustc_nounwind ] |
1744 | #[rustc_intrinsic ] |
1745 | pub const unsafe fn cttz_nonzero<T: Copy>(x: T) -> u32; |
1746 | |
1747 | /// Reverses the bytes in an integer type `T`. |
1748 | /// |
1749 | /// Note that, unlike most intrinsics, this is safe to call; |
1750 | /// it does not require an `unsafe` block. |
1751 | /// Therefore, implementations must not require the user to uphold |
1752 | /// any safety invariants. |
1753 | /// |
1754 | /// The stabilized versions of this intrinsic are available on the integer |
1755 | /// primitives via the `swap_bytes` method. For example, |
1756 | /// [`u32::swap_bytes`] |
1757 | #[rustc_intrinsic_const_stable_indirect] |
1758 | #[rustc_nounwind ] |
1759 | #[rustc_intrinsic ] |
1760 | pub const fn bswap<T: Copy>(x: T) -> T; |
1761 | |
1762 | /// Reverses the bits in an integer type `T`. |
1763 | /// |
1764 | /// Note that, unlike most intrinsics, this is safe to call; |
1765 | /// it does not require an `unsafe` block. |
1766 | /// Therefore, implementations must not require the user to uphold |
1767 | /// any safety invariants. |
1768 | /// |
1769 | /// The stabilized versions of this intrinsic are available on the integer |
1770 | /// primitives via the `reverse_bits` method. For example, |
1771 | /// [`u32::reverse_bits`] |
1772 | #[rustc_intrinsic_const_stable_indirect] |
1773 | #[rustc_nounwind ] |
1774 | #[rustc_intrinsic ] |
1775 | pub const fn bitreverse<T: Copy>(x: T) -> T; |
1776 | |
1777 | /// Does a three-way comparison between the two arguments, |
1778 | /// which must be of character or integer (signed or unsigned) type. |
1779 | /// |
1780 | /// This was originally added because it greatly simplified the MIR in `cmp` |
1781 | /// implementations, and then LLVM 20 added a backend intrinsic for it too. |
1782 | /// |
1783 | /// The stabilized version of this intrinsic is [`Ord::cmp`]. |
1784 | #[rustc_intrinsic_const_stable_indirect] |
1785 | #[rustc_nounwind ] |
1786 | #[rustc_intrinsic ] |
1787 | pub const fn three_way_compare<T: Copy>(lhs: T, rhss: T) -> crate::cmp::Ordering; |
1788 | |
1789 | /// Combine two values which have no bits in common. |
1790 | /// |
1791 | /// This allows the backend to implement it as `a + b` *or* `a | b`, |
1792 | /// depending which is easier to implement on a specific target. |
1793 | /// |
1794 | /// # Safety |
1795 | /// |
1796 | /// Requires that `(a & b) == 0`, or equivalently that `(a | b) == (a + b)`. |
1797 | /// |
1798 | /// Otherwise it's immediate UB. |
1799 | #[rustc_const_unstable (feature = "disjoint_bitor" , issue = "135758" )] |
1800 | #[rustc_nounwind ] |
1801 | #[rustc_intrinsic ] |
1802 | #[track_caller ] |
1803 | #[miri::intrinsic_fallback_is_spec] // the fallbacks all `assume` to tell Miri |
1804 | pub const unsafe fn disjoint_bitor<T: ~const fallback::DisjointBitOr>(a: T, b: T) -> T { |
1805 | // SAFETY: same preconditions as this function. |
1806 | unsafe { fallback::DisjointBitOr::disjoint_bitor(self:a, other:b) } |
1807 | } |
1808 | |
1809 | /// Performs checked integer addition. |
1810 | /// |
1811 | /// Note that, unlike most intrinsics, this is safe to call; |
1812 | /// it does not require an `unsafe` block. |
1813 | /// Therefore, implementations must not require the user to uphold |
1814 | /// any safety invariants. |
1815 | /// |
1816 | /// The stabilized versions of this intrinsic are available on the integer |
1817 | /// primitives via the `overflowing_add` method. For example, |
1818 | /// [`u32::overflowing_add`] |
1819 | #[rustc_intrinsic_const_stable_indirect] |
1820 | #[rustc_nounwind ] |
1821 | #[rustc_intrinsic ] |
1822 | pub const fn add_with_overflow<T: Copy>(x: T, y: T) -> (T, bool); |
1823 | |
1824 | /// Performs checked integer subtraction |
1825 | /// |
1826 | /// Note that, unlike most intrinsics, this is safe to call; |
1827 | /// it does not require an `unsafe` block. |
1828 | /// Therefore, implementations must not require the user to uphold |
1829 | /// any safety invariants. |
1830 | /// |
1831 | /// The stabilized versions of this intrinsic are available on the integer |
1832 | /// primitives via the `overflowing_sub` method. For example, |
1833 | /// [`u32::overflowing_sub`] |
1834 | #[rustc_intrinsic_const_stable_indirect] |
1835 | #[rustc_nounwind ] |
1836 | #[rustc_intrinsic ] |
1837 | pub const fn sub_with_overflow<T: Copy>(x: T, y: T) -> (T, bool); |
1838 | |
1839 | /// Performs checked integer multiplication |
1840 | /// |
1841 | /// Note that, unlike most intrinsics, this is safe to call; |
1842 | /// it does not require an `unsafe` block. |
1843 | /// Therefore, implementations must not require the user to uphold |
1844 | /// any safety invariants. |
1845 | /// |
1846 | /// The stabilized versions of this intrinsic are available on the integer |
1847 | /// primitives via the `overflowing_mul` method. For example, |
1848 | /// [`u32::overflowing_mul`] |
1849 | #[rustc_intrinsic_const_stable_indirect] |
1850 | #[rustc_nounwind ] |
1851 | #[rustc_intrinsic ] |
1852 | pub const fn mul_with_overflow<T: Copy>(x: T, y: T) -> (T, bool); |
1853 | |
1854 | /// Performs full-width multiplication and addition with a carry: |
1855 | /// `multiplier * multiplicand + addend + carry`. |
1856 | /// |
1857 | /// This is possible without any overflow. For `uN`: |
1858 | /// MAX * MAX + MAX + MAX |
1859 | /// => (2ⁿ-1) × (2ⁿ-1) + (2ⁿ-1) + (2ⁿ-1) |
1860 | /// => (2²ⁿ - 2ⁿ⁺¹ + 1) + (2ⁿ⁺¹ - 2) |
1861 | /// => 2²ⁿ - 1 |
1862 | /// |
1863 | /// For `iN`, the upper bound is MIN * MIN + MAX + MAX => 2²ⁿ⁻² + 2ⁿ - 2, |
1864 | /// and the lower bound is MAX * MIN + MIN + MIN => -2²ⁿ⁻² - 2ⁿ + 2ⁿ⁺¹. |
1865 | /// |
1866 | /// This currently supports unsigned integers *only*, no signed ones. |
1867 | /// The stabilized versions of this intrinsic are available on integers. |
1868 | #[unstable (feature = "core_intrinsics" , issue = "none" )] |
1869 | #[rustc_const_unstable (feature = "const_carrying_mul_add" , issue = "85532" )] |
1870 | #[rustc_nounwind ] |
1871 | #[rustc_intrinsic ] |
1872 | #[miri::intrinsic_fallback_is_spec] |
1873 | pub const fn carrying_mul_add<T: ~const fallback::CarryingMulAdd<Unsigned = U>, U>( |
1874 | multiplier: T, |
1875 | multiplicand: T, |
1876 | addend: T, |
1877 | carry: T, |
1878 | ) -> (U, T) { |
1879 | multiplier.carrying_mul_add(multiplicand, addend, carry) |
1880 | } |
1881 | |
1882 | /// Performs an exact division, resulting in undefined behavior where |
1883 | /// `x % y != 0` or `y == 0` or `x == T::MIN && y == -1` |
1884 | /// |
1885 | /// This intrinsic does not have a stable counterpart. |
1886 | #[rustc_intrinsic_const_stable_indirect] |
1887 | #[rustc_nounwind ] |
1888 | #[rustc_intrinsic ] |
1889 | pub const unsafe fn exact_div<T: Copy>(x: T, y: T) -> T; |
1890 | |
1891 | /// Performs an unchecked division, resulting in undefined behavior |
1892 | /// where `y == 0` or `x == T::MIN && y == -1` |
1893 | /// |
1894 | /// Safe wrappers for this intrinsic are available on the integer |
1895 | /// primitives via the `checked_div` method. For example, |
1896 | /// [`u32::checked_div`] |
1897 | #[rustc_intrinsic_const_stable_indirect] |
1898 | #[rustc_nounwind ] |
1899 | #[rustc_intrinsic ] |
1900 | pub const unsafe fn unchecked_div<T: Copy>(x: T, y: T) -> T; |
1901 | /// Returns the remainder of an unchecked division, resulting in |
1902 | /// undefined behavior when `y == 0` or `x == T::MIN && y == -1` |
1903 | /// |
1904 | /// Safe wrappers for this intrinsic are available on the integer |
1905 | /// primitives via the `checked_rem` method. For example, |
1906 | /// [`u32::checked_rem`] |
1907 | #[rustc_intrinsic_const_stable_indirect] |
1908 | #[rustc_nounwind ] |
1909 | #[rustc_intrinsic ] |
1910 | pub const unsafe fn unchecked_rem<T: Copy>(x: T, y: T) -> T; |
1911 | |
1912 | /// Performs an unchecked left shift, resulting in undefined behavior when |
1913 | /// `y < 0` or `y >= N`, where N is the width of T in bits. |
1914 | /// |
1915 | /// Safe wrappers for this intrinsic are available on the integer |
1916 | /// primitives via the `checked_shl` method. For example, |
1917 | /// [`u32::checked_shl`] |
1918 | #[rustc_intrinsic_const_stable_indirect] |
1919 | #[rustc_nounwind ] |
1920 | #[rustc_intrinsic ] |
1921 | pub const unsafe fn unchecked_shl<T: Copy, U: Copy>(x: T, y: U) -> T; |
1922 | /// Performs an unchecked right shift, resulting in undefined behavior when |
1923 | /// `y < 0` or `y >= N`, where N is the width of T in bits. |
1924 | /// |
1925 | /// Safe wrappers for this intrinsic are available on the integer |
1926 | /// primitives via the `checked_shr` method. For example, |
1927 | /// [`u32::checked_shr`] |
1928 | #[rustc_intrinsic_const_stable_indirect] |
1929 | #[rustc_nounwind ] |
1930 | #[rustc_intrinsic ] |
1931 | pub const unsafe fn unchecked_shr<T: Copy, U: Copy>(x: T, y: U) -> T; |
1932 | |
1933 | /// Returns the result of an unchecked addition, resulting in |
1934 | /// undefined behavior when `x + y > T::MAX` or `x + y < T::MIN`. |
1935 | /// |
1936 | /// The stable counterpart of this intrinsic is `unchecked_add` on the various |
1937 | /// integer types, such as [`u16::unchecked_add`] and [`i64::unchecked_add`]. |
1938 | #[rustc_intrinsic_const_stable_indirect] |
1939 | #[rustc_nounwind ] |
1940 | #[rustc_intrinsic ] |
1941 | pub const unsafe fn unchecked_add<T: Copy>(x: T, y: T) -> T; |
1942 | |
1943 | /// Returns the result of an unchecked subtraction, resulting in |
1944 | /// undefined behavior when `x - y > T::MAX` or `x - y < T::MIN`. |
1945 | /// |
1946 | /// The stable counterpart of this intrinsic is `unchecked_sub` on the various |
1947 | /// integer types, such as [`u16::unchecked_sub`] and [`i64::unchecked_sub`]. |
1948 | #[rustc_intrinsic_const_stable_indirect] |
1949 | #[rustc_nounwind ] |
1950 | #[rustc_intrinsic ] |
1951 | pub const unsafe fn unchecked_sub<T: Copy>(x: T, y: T) -> T; |
1952 | |
1953 | /// Returns the result of an unchecked multiplication, resulting in |
1954 | /// undefined behavior when `x * y > T::MAX` or `x * y < T::MIN`. |
1955 | /// |
1956 | /// The stable counterpart of this intrinsic is `unchecked_mul` on the various |
1957 | /// integer types, such as [`u16::unchecked_mul`] and [`i64::unchecked_mul`]. |
1958 | #[rustc_intrinsic_const_stable_indirect] |
1959 | #[rustc_nounwind ] |
1960 | #[rustc_intrinsic ] |
1961 | pub const unsafe fn unchecked_mul<T: Copy>(x: T, y: T) -> T; |
1962 | |
1963 | /// Performs rotate left. |
1964 | /// |
1965 | /// Note that, unlike most intrinsics, this is safe to call; |
1966 | /// it does not require an `unsafe` block. |
1967 | /// Therefore, implementations must not require the user to uphold |
1968 | /// any safety invariants. |
1969 | /// |
1970 | /// The stabilized versions of this intrinsic are available on the integer |
1971 | /// primitives via the `rotate_left` method. For example, |
1972 | /// [`u32::rotate_left`] |
1973 | #[rustc_intrinsic_const_stable_indirect] |
1974 | #[rustc_nounwind ] |
1975 | #[rustc_intrinsic ] |
1976 | pub const fn rotate_left<T: Copy>(x: T, shift: u32) -> T; |
1977 | |
1978 | /// Performs rotate right. |
1979 | /// |
1980 | /// Note that, unlike most intrinsics, this is safe to call; |
1981 | /// it does not require an `unsafe` block. |
1982 | /// Therefore, implementations must not require the user to uphold |
1983 | /// any safety invariants. |
1984 | /// |
1985 | /// The stabilized versions of this intrinsic are available on the integer |
1986 | /// primitives via the `rotate_right` method. For example, |
1987 | /// [`u32::rotate_right`] |
1988 | #[rustc_intrinsic_const_stable_indirect] |
1989 | #[rustc_nounwind ] |
1990 | #[rustc_intrinsic ] |
1991 | pub const fn rotate_right<T: Copy>(x: T, shift: u32) -> T; |
1992 | |
1993 | /// Returns (a + b) mod 2<sup>N</sup>, where N is the width of T in bits. |
1994 | /// |
1995 | /// Note that, unlike most intrinsics, this is safe to call; |
1996 | /// it does not require an `unsafe` block. |
1997 | /// Therefore, implementations must not require the user to uphold |
1998 | /// any safety invariants. |
1999 | /// |
2000 | /// The stabilized versions of this intrinsic are available on the integer |
2001 | /// primitives via the `wrapping_add` method. For example, |
2002 | /// [`u32::wrapping_add`] |
2003 | #[rustc_intrinsic_const_stable_indirect] |
2004 | #[rustc_nounwind ] |
2005 | #[rustc_intrinsic ] |
2006 | pub const fn wrapping_add<T: Copy>(a: T, b: T) -> T; |
2007 | /// Returns (a - b) mod 2<sup>N</sup>, where N is the width of T in bits. |
2008 | /// |
2009 | /// Note that, unlike most intrinsics, this is safe to call; |
2010 | /// it does not require an `unsafe` block. |
2011 | /// Therefore, implementations must not require the user to uphold |
2012 | /// any safety invariants. |
2013 | /// |
2014 | /// The stabilized versions of this intrinsic are available on the integer |
2015 | /// primitives via the `wrapping_sub` method. For example, |
2016 | /// [`u32::wrapping_sub`] |
2017 | #[rustc_intrinsic_const_stable_indirect] |
2018 | #[rustc_nounwind ] |
2019 | #[rustc_intrinsic ] |
2020 | pub const fn wrapping_sub<T: Copy>(a: T, b: T) -> T; |
2021 | /// Returns (a * b) mod 2<sup>N</sup>, where N is the width of T in bits. |
2022 | /// |
2023 | /// Note that, unlike most intrinsics, this is safe to call; |
2024 | /// it does not require an `unsafe` block. |
2025 | /// Therefore, implementations must not require the user to uphold |
2026 | /// any safety invariants. |
2027 | /// |
2028 | /// The stabilized versions of this intrinsic are available on the integer |
2029 | /// primitives via the `wrapping_mul` method. For example, |
2030 | /// [`u32::wrapping_mul`] |
2031 | #[rustc_intrinsic_const_stable_indirect] |
2032 | #[rustc_nounwind ] |
2033 | #[rustc_intrinsic ] |
2034 | pub const fn wrapping_mul<T: Copy>(a: T, b: T) -> T; |
2035 | |
2036 | /// Computes `a + b`, saturating at numeric bounds. |
2037 | /// |
2038 | /// Note that, unlike most intrinsics, this is safe to call; |
2039 | /// it does not require an `unsafe` block. |
2040 | /// Therefore, implementations must not require the user to uphold |
2041 | /// any safety invariants. |
2042 | /// |
2043 | /// The stabilized versions of this intrinsic are available on the integer |
2044 | /// primitives via the `saturating_add` method. For example, |
2045 | /// [`u32::saturating_add`] |
2046 | #[rustc_intrinsic_const_stable_indirect] |
2047 | #[rustc_nounwind ] |
2048 | #[rustc_intrinsic ] |
2049 | pub const fn saturating_add<T: Copy>(a: T, b: T) -> T; |
2050 | /// Computes `a - b`, saturating at numeric bounds. |
2051 | /// |
2052 | /// Note that, unlike most intrinsics, this is safe to call; |
2053 | /// it does not require an `unsafe` block. |
2054 | /// Therefore, implementations must not require the user to uphold |
2055 | /// any safety invariants. |
2056 | /// |
2057 | /// The stabilized versions of this intrinsic are available on the integer |
2058 | /// primitives via the `saturating_sub` method. For example, |
2059 | /// [`u32::saturating_sub`] |
2060 | #[rustc_intrinsic_const_stable_indirect] |
2061 | #[rustc_nounwind ] |
2062 | #[rustc_intrinsic ] |
2063 | pub const fn saturating_sub<T: Copy>(a: T, b: T) -> T; |
2064 | |
2065 | /// This is an implementation detail of [`crate::ptr::read`] and should |
2066 | /// not be used anywhere else. See its comments for why this exists. |
2067 | /// |
2068 | /// This intrinsic can *only* be called where the pointer is a local without |
2069 | /// projections (`read_via_copy(ptr)`, not `read_via_copy(*ptr)`) so that it |
2070 | /// trivially obeys runtime-MIR rules about derefs in operands. |
2071 | #[rustc_intrinsic_const_stable_indirect] |
2072 | #[rustc_nounwind ] |
2073 | #[rustc_intrinsic ] |
2074 | pub const unsafe fn read_via_copy<T>(ptr: *const T) -> T; |
2075 | |
2076 | /// This is an implementation detail of [`crate::ptr::write`] and should |
2077 | /// not be used anywhere else. See its comments for why this exists. |
2078 | /// |
2079 | /// This intrinsic can *only* be called where the pointer is a local without |
2080 | /// projections (`write_via_move(ptr, x)`, not `write_via_move(*ptr, x)`) so |
2081 | /// that it trivially obeys runtime-MIR rules about derefs in operands. |
2082 | #[rustc_intrinsic_const_stable_indirect] |
2083 | #[rustc_nounwind ] |
2084 | #[rustc_intrinsic ] |
2085 | pub const unsafe fn write_via_move<T>(ptr: *mut T, value: T); |
2086 | |
2087 | /// Returns the value of the discriminant for the variant in 'v'; |
2088 | /// if `T` has no discriminant, returns `0`. |
2089 | /// |
2090 | /// Note that, unlike most intrinsics, this is safe to call; |
2091 | /// it does not require an `unsafe` block. |
2092 | /// Therefore, implementations must not require the user to uphold |
2093 | /// any safety invariants. |
2094 | /// |
2095 | /// The stabilized version of this intrinsic is [`core::mem::discriminant`]. |
2096 | #[rustc_intrinsic_const_stable_indirect] |
2097 | #[rustc_nounwind ] |
2098 | #[rustc_intrinsic ] |
2099 | pub const fn discriminant_value<T>(v: &T) -> <T as DiscriminantKind>::Discriminant; |
2100 | |
2101 | /// Rust's "try catch" construct for unwinding. Invokes the function pointer `try_fn` with the |
2102 | /// data pointer `data`, and calls `catch_fn` if unwinding occurs while `try_fn` runs. |
2103 | /// Returns `1` if unwinding occurred and `catch_fn` was called; returns `0` otherwise. |
2104 | /// |
2105 | /// `catch_fn` must not unwind. |
2106 | /// |
2107 | /// The third argument is a function called if an unwind occurs (both Rust `panic` and foreign |
2108 | /// unwinds). This function takes the data pointer and a pointer to the target- and |
2109 | /// runtime-specific exception object that was caught. |
2110 | /// |
2111 | /// Note that in the case of a foreign unwinding operation, the exception object data may not be |
2112 | /// safely usable from Rust, and should not be directly exposed via the standard library. To |
2113 | /// prevent unsafe access, the library implementation may either abort the process or present an |
2114 | /// opaque error type to the user. |
2115 | /// |
2116 | /// For more information, see the compiler's source, as well as the documentation for the stable |
2117 | /// version of this intrinsic, `std::panic::catch_unwind`. |
2118 | #[rustc_intrinsic ] |
2119 | #[rustc_nounwind ] |
2120 | pub unsafe fn catch_unwind( |
2121 | _try_fn: fn(*mut u8), |
2122 | _data: *mut u8, |
2123 | _catch_fn: fn(*mut u8, *mut u8), |
2124 | ) -> i32; |
2125 | |
2126 | /// Emits a `nontemporal` store, which gives a hint to the CPU that the data should not be held |
2127 | /// in cache. Except for performance, this is fully equivalent to `ptr.write(val)`. |
2128 | /// |
2129 | /// Not all architectures provide such an operation. For instance, x86 does not: while `MOVNT` |
2130 | /// exists, that operation is *not* equivalent to `ptr.write(val)` (`MOVNT` writes can be reordered |
2131 | /// in ways that are not allowed for regular writes). |
2132 | #[rustc_intrinsic ] |
2133 | #[rustc_nounwind ] |
2134 | pub unsafe fn nontemporal_store<T>(ptr: *mut T, val: T); |
2135 | |
2136 | /// See documentation of `<*const T>::offset_from` for details. |
2137 | #[rustc_intrinsic_const_stable_indirect] |
2138 | #[rustc_nounwind ] |
2139 | #[rustc_intrinsic ] |
2140 | pub const unsafe fn ptr_offset_from<T>(ptr: *const T, base: *const T) -> isize; |
2141 | |
2142 | /// See documentation of `<*const T>::offset_from_unsigned` for details. |
2143 | #[rustc_nounwind ] |
2144 | #[rustc_intrinsic ] |
2145 | #[rustc_intrinsic_const_stable_indirect] |
2146 | pub const unsafe fn ptr_offset_from_unsigned<T>(ptr: *const T, base: *const T) -> usize; |
2147 | |
2148 | /// See documentation of `<*const T>::guaranteed_eq` for details. |
2149 | /// Returns `2` if the result is unknown. |
2150 | /// Returns `1` if the pointers are guaranteed equal. |
2151 | /// Returns `0` if the pointers are guaranteed inequal. |
2152 | #[rustc_intrinsic ] |
2153 | #[rustc_nounwind ] |
2154 | #[rustc_do_not_const_check ] |
2155 | #[inline ] |
2156 | #[miri::intrinsic_fallback_is_spec] |
2157 | pub const fn ptr_guaranteed_cmp<T>(ptr: *const T, other: *const T) -> u8 { |
2158 | (ptr == other) as u8 |
2159 | } |
2160 | |
2161 | /// Determines whether the raw bytes of the two values are equal. |
2162 | /// |
2163 | /// This is particularly handy for arrays, since it allows things like just |
2164 | /// comparing `i96`s instead of forcing `alloca`s for `[6 x i16]`. |
2165 | /// |
2166 | /// Above some backend-decided threshold this will emit calls to `memcmp`, |
2167 | /// like slice equality does, instead of causing massive code size. |
2168 | /// |
2169 | /// Since this works by comparing the underlying bytes, the actual `T` is |
2170 | /// not particularly important. It will be used for its size and alignment, |
2171 | /// but any validity restrictions will be ignored, not enforced. |
2172 | /// |
2173 | /// # Safety |
2174 | /// |
2175 | /// It's UB to call this if any of the *bytes* in `*a` or `*b` are uninitialized. |
2176 | /// Note that this is a stricter criterion than just the *values* being |
2177 | /// fully-initialized: if `T` has padding, it's UB to call this intrinsic. |
2178 | /// |
2179 | /// At compile-time, it is furthermore UB to call this if any of the bytes |
2180 | /// in `*a` or `*b` have provenance. |
2181 | /// |
2182 | /// (The implementation is allowed to branch on the results of comparisons, |
2183 | /// which is UB if any of their inputs are `undef`.) |
2184 | #[rustc_nounwind ] |
2185 | #[rustc_intrinsic ] |
2186 | pub const unsafe fn raw_eq<T>(a: &T, b: &T) -> bool; |
2187 | |
2188 | /// Lexicographically compare `[left, left + bytes)` and `[right, right + bytes)` |
2189 | /// as unsigned bytes, returning negative if `left` is less, zero if all the |
2190 | /// bytes match, or positive if `left` is greater. |
2191 | /// |
2192 | /// This underlies things like `<[u8]>::cmp`, and will usually lower to `memcmp`. |
2193 | /// |
2194 | /// # Safety |
2195 | /// |
2196 | /// `left` and `right` must each be [valid] for reads of `bytes` bytes. |
2197 | /// |
2198 | /// Note that this applies to the whole range, not just until the first byte |
2199 | /// that differs. That allows optimizations that can read in large chunks. |
2200 | /// |
2201 | /// [valid]: crate::ptr#safety |
2202 | #[rustc_nounwind ] |
2203 | #[rustc_intrinsic ] |
2204 | pub const unsafe fn compare_bytes(left: *const u8, right: *const u8, bytes: usize) -> i32; |
2205 | |
2206 | /// See documentation of [`std::hint::black_box`] for details. |
2207 | /// |
2208 | /// [`std::hint::black_box`]: crate::hint::black_box |
2209 | #[rustc_nounwind ] |
2210 | #[rustc_intrinsic ] |
2211 | #[rustc_intrinsic_const_stable_indirect] |
2212 | pub const fn black_box<T>(dummy: T) -> T; |
2213 | |
2214 | /// Selects which function to call depending on the context. |
2215 | /// |
2216 | /// If this function is evaluated at compile-time, then a call to this |
2217 | /// intrinsic will be replaced with a call to `called_in_const`. It gets |
2218 | /// replaced with a call to `called_at_rt` otherwise. |
2219 | /// |
2220 | /// This function is safe to call, but note the stability concerns below. |
2221 | /// |
2222 | /// # Type Requirements |
2223 | /// |
2224 | /// The two functions must be both function items. They cannot be function |
2225 | /// pointers or closures. The first function must be a `const fn`. |
2226 | /// |
2227 | /// `arg` will be the tupled arguments that will be passed to either one of |
2228 | /// the two functions, therefore, both functions must accept the same type of |
2229 | /// arguments. Both functions must return RET. |
2230 | /// |
2231 | /// # Stability concerns |
2232 | /// |
2233 | /// Rust has not yet decided that `const fn` are allowed to tell whether |
2234 | /// they run at compile-time or at runtime. Therefore, when using this |
2235 | /// intrinsic anywhere that can be reached from stable, it is crucial that |
2236 | /// the end-to-end behavior of the stable `const fn` is the same for both |
2237 | /// modes of execution. (Here, Undefined Behavior is considered "the same" |
2238 | /// as any other behavior, so if the function exhibits UB at runtime then |
2239 | /// it may do whatever it wants at compile-time.) |
2240 | /// |
2241 | /// Here is an example of how this could cause a problem: |
2242 | /// ```no_run |
2243 | /// #![feature(const_eval_select)] |
2244 | /// #![feature(core_intrinsics)] |
2245 | /// # #![allow(internal_features)] |
2246 | /// use std::intrinsics::const_eval_select; |
2247 | /// |
2248 | /// // Standard library |
2249 | /// pub const fn inconsistent() -> i32 { |
2250 | /// fn runtime() -> i32 { 1 } |
2251 | /// const fn compiletime() -> i32 { 2 } |
2252 | /// |
2253 | /// // ⚠ This code violates the required equivalence of `compiletime` |
2254 | /// // and `runtime`. |
2255 | /// const_eval_select((), compiletime, runtime) |
2256 | /// } |
2257 | /// |
2258 | /// // User Crate |
2259 | /// const X: i32 = inconsistent(); |
2260 | /// let x = inconsistent(); |
2261 | /// assert_eq!(x, X); |
2262 | /// ``` |
2263 | /// |
2264 | /// Currently such an assertion would always succeed; until Rust decides |
2265 | /// otherwise, that principle should not be violated. |
2266 | #[rustc_const_unstable (feature = "const_eval_select" , issue = "124625" )] |
2267 | #[rustc_intrinsic ] |
2268 | pub const fn const_eval_select<ARG: Tuple, F, G, RET>( |
2269 | _arg: ARG, |
2270 | _called_in_const: F, |
2271 | _called_at_rt: G, |
2272 | ) -> RET |
2273 | where |
2274 | G: FnOnce<ARG, Output = RET>, |
2275 | F: FnOnce<ARG, Output = RET>; |
2276 | |
2277 | /// A macro to make it easier to invoke const_eval_select. Use as follows: |
2278 | /// ```rust,ignore (just a macro example) |
2279 | /// const_eval_select!( |
2280 | /// @capture { arg1: i32 = some_expr, arg2: T = other_expr } -> U: |
2281 | /// if const #[attributes_for_const_arm] { |
2282 | /// // Compile-time code goes here. |
2283 | /// } else #[attributes_for_runtime_arm] { |
2284 | /// // Run-time code goes here. |
2285 | /// } |
2286 | /// ) |
2287 | /// ``` |
2288 | /// The `@capture` block declares which surrounding variables / expressions can be |
2289 | /// used inside the `if const`. |
2290 | /// Note that the two arms of this `if` really each become their own function, which is why the |
2291 | /// macro supports setting attributes for those functions. The runtime function is always |
2292 | /// markes as `#[inline]`. |
2293 | /// |
2294 | /// See [`const_eval_select()`] for the rules and requirements around that intrinsic. |
2295 | pub(crate) macro const_eval_select { |
2296 | ( |
2297 | @capture$([$($binders:tt)*])? { $($arg:ident : $ty:ty = $val:expr),* $(,)? } $( -> $ret:ty )? : |
2298 | if const |
2299 | $(#[$compiletime_attr:meta])* $compiletime:block |
2300 | else |
2301 | $(#[$runtime_attr:meta])* $runtime:block |
2302 | ) => { |
2303 | // Use the `noinline` arm, after adding explicit `inline` attributes |
2304 | $crate::intrinsics::const_eval_select!( |
2305 | @capture$([$($binders)*])? { $($arg : $ty = $val),* } $(-> $ret)? : |
2306 | #[noinline] |
2307 | if const |
2308 | #[inline] // prevent codegen on this function |
2309 | $(#[$compiletime_attr])* |
2310 | $compiletime |
2311 | else |
2312 | #[inline] // avoid the overhead of an extra fn call |
2313 | $(#[$runtime_attr])* |
2314 | $runtime |
2315 | ) |
2316 | }, |
2317 | // With a leading #[noinline], we don't add inline attributes |
2318 | ( |
2319 | @capture$([$($binders:tt)*])? { $($arg:ident : $ty:ty = $val:expr),* $(,)? } $( -> $ret:ty )? : |
2320 | #[noinline] |
2321 | if const |
2322 | $(#[$compiletime_attr:meta])* $compiletime:block |
2323 | else |
2324 | $(#[$runtime_attr:meta])* $runtime:block |
2325 | ) => {{ |
2326 | $(#[$runtime_attr])* |
2327 | fn runtime$(<$($binders)*>)?($($arg: $ty),*) $( -> $ret )? { |
2328 | $runtime |
2329 | } |
2330 | |
2331 | $(#[$compiletime_attr])* |
2332 | const fn compiletime$(<$($binders)*>)?($($arg: $ty),*) $( -> $ret )? { |
2333 | // Don't warn if one of the arguments is unused. |
2334 | $(let _ = $arg;)* |
2335 | |
2336 | $compiletime |
2337 | } |
2338 | |
2339 | const_eval_select(($($val,)*), compiletime, runtime) |
2340 | }}, |
2341 | // We support leaving away the `val` expressions for *all* arguments |
2342 | // (but not for *some* arguments, that's too tricky). |
2343 | ( |
2344 | @capture$([$($binders:tt)*])? { $($arg:ident : $ty:ty),* $(,)? } $( -> $ret:ty )? : |
2345 | if const |
2346 | $(#[$compiletime_attr:meta])* $compiletime:block |
2347 | else |
2348 | $(#[$runtime_attr:meta])* $runtime:block |
2349 | ) => { |
2350 | $crate::intrinsics::const_eval_select!( |
2351 | @capture$([$($binders)*])? { $($arg : $ty = $arg),* } $(-> $ret)? : |
2352 | if const |
2353 | $(#[$compiletime_attr])* $compiletime |
2354 | else |
2355 | $(#[$runtime_attr])* $runtime |
2356 | ) |
2357 | }, |
2358 | } |
2359 | |
2360 | /// Returns whether the argument's value is statically known at |
2361 | /// compile-time. |
2362 | /// |
2363 | /// This is useful when there is a way of writing the code that will |
2364 | /// be *faster* when some variables have known values, but *slower* |
2365 | /// in the general case: an `if is_val_statically_known(var)` can be used |
2366 | /// to select between these two variants. The `if` will be optimized away |
2367 | /// and only the desired branch remains. |
2368 | /// |
2369 | /// Formally speaking, this function non-deterministically returns `true` |
2370 | /// or `false`, and the caller has to ensure sound behavior for both cases. |
2371 | /// In other words, the following code has *Undefined Behavior*: |
2372 | /// |
2373 | /// ```no_run |
2374 | /// #![feature(core_intrinsics)] |
2375 | /// # #![allow(internal_features)] |
2376 | /// use std::hint::unreachable_unchecked; |
2377 | /// use std::intrinsics::is_val_statically_known; |
2378 | /// |
2379 | /// if !is_val_statically_known(0) { unsafe { unreachable_unchecked(); } } |
2380 | /// ``` |
2381 | /// |
2382 | /// This also means that the following code's behavior is unspecified; it |
2383 | /// may panic, or it may not: |
2384 | /// |
2385 | /// ```no_run |
2386 | /// #![feature(core_intrinsics)] |
2387 | /// # #![allow(internal_features)] |
2388 | /// use std::intrinsics::is_val_statically_known; |
2389 | /// |
2390 | /// assert_eq!(is_val_statically_known(0), is_val_statically_known(0)); |
2391 | /// ``` |
2392 | /// |
2393 | /// Unsafe code may not rely on `is_val_statically_known` returning any |
2394 | /// particular value, ever. However, the compiler will generally make it |
2395 | /// return `true` only if the value of the argument is actually known. |
2396 | /// |
2397 | /// # Stability concerns |
2398 | /// |
2399 | /// While it is safe to call, this intrinsic may behave differently in |
2400 | /// a `const` context than otherwise. See the [`const_eval_select()`] |
2401 | /// documentation for an explanation of the issues this can cause. Unlike |
2402 | /// `const_eval_select`, this intrinsic isn't guaranteed to behave |
2403 | /// deterministically even in a `const` context. |
2404 | /// |
2405 | /// # Type Requirements |
2406 | /// |
2407 | /// `T` must be either a `bool`, a `char`, a primitive numeric type (e.g. `f32`, |
2408 | /// but not `NonZeroISize`), or any thin pointer (e.g. `*mut String`). |
2409 | /// Any other argument types *may* cause a compiler error. |
2410 | /// |
2411 | /// ## Pointers |
2412 | /// |
2413 | /// When the input is a pointer, only the pointer itself is |
2414 | /// ever considered. The pointee has no effect. Currently, these functions |
2415 | /// behave identically: |
2416 | /// |
2417 | /// ``` |
2418 | /// #![feature(core_intrinsics)] |
2419 | /// # #![allow(internal_features)] |
2420 | /// use std::intrinsics::is_val_statically_known; |
2421 | /// |
2422 | /// fn foo(x: &i32) -> bool { |
2423 | /// is_val_statically_known(x) |
2424 | /// } |
2425 | /// |
2426 | /// fn bar(x: &i32) -> bool { |
2427 | /// is_val_statically_known( |
2428 | /// (x as *const i32).addr() |
2429 | /// ) |
2430 | /// } |
2431 | /// # _ = foo(&5_i32); |
2432 | /// # _ = bar(&5_i32); |
2433 | /// ``` |
2434 | #[rustc_const_stable_indirect] |
2435 | #[rustc_nounwind ] |
2436 | #[unstable (feature = "core_intrinsics" , issue = "none" )] |
2437 | #[rustc_intrinsic ] |
2438 | pub const fn is_val_statically_known<T: Copy>(_arg: T) -> bool { |
2439 | false |
2440 | } |
2441 | |
2442 | /// Non-overlapping *typed* swap of a single value. |
2443 | /// |
2444 | /// The codegen backends will replace this with a better implementation when |
2445 | /// `T` is a simple type that can be loaded and stored as an immediate. |
2446 | /// |
2447 | /// The stabilized form of this intrinsic is [`crate::mem::swap`]. |
2448 | /// |
2449 | /// # Safety |
2450 | /// Behavior is undefined if any of the following conditions are violated: |
2451 | /// |
2452 | /// * Both `x` and `y` must be [valid] for both reads and writes. |
2453 | /// |
2454 | /// * Both `x` and `y` must be properly aligned. |
2455 | /// |
2456 | /// * The region of memory beginning at `x` must *not* overlap with the region of memory |
2457 | /// beginning at `y`. |
2458 | /// |
2459 | /// * The memory pointed by `x` and `y` must both contain values of type `T`. |
2460 | /// |
2461 | /// [valid]: crate::ptr#safety |
2462 | #[rustc_nounwind ] |
2463 | #[inline ] |
2464 | #[rustc_intrinsic ] |
2465 | #[rustc_intrinsic_const_stable_indirect] |
2466 | pub const unsafe fn typed_swap_nonoverlapping<T>(x: *mut T, y: *mut T) { |
2467 | // SAFETY: The caller provided single non-overlapping items behind |
2468 | // pointers, so swapping them with `count: 1` is fine. |
2469 | unsafe { ptr::swap_nonoverlapping(x, y, count:1) }; |
2470 | } |
2471 | |
2472 | /// Returns whether we should perform some UB-checking at runtime. This eventually evaluates to |
2473 | /// `cfg!(ub_checks)`, but behaves different from `cfg!` when mixing crates built with different |
2474 | /// flags: if the crate has UB checks enabled or carries the `#[rustc_preserve_ub_checks]` |
2475 | /// attribute, evaluation is delayed until monomorphization (or until the call gets inlined into |
2476 | /// a crate that does not delay evaluation further); otherwise it can happen any time. |
2477 | /// |
2478 | /// The common case here is a user program built with ub_checks linked against the distributed |
2479 | /// sysroot which is built without ub_checks but with `#[rustc_preserve_ub_checks]`. |
2480 | /// For code that gets monomorphized in the user crate (i.e., generic functions and functions with |
2481 | /// `#[inline]`), gating assertions on `ub_checks()` rather than `cfg!(ub_checks)` means that |
2482 | /// assertions are enabled whenever the *user crate* has UB checks enabled. However, if the |
2483 | /// user has UB checks disabled, the checks will still get optimized out. This intrinsic is |
2484 | /// primarily used by [`crate::ub_checks::assert_unsafe_precondition`]. |
2485 | #[rustc_intrinsic_const_stable_indirect] // just for UB checks |
2486 | #[inline (always)] |
2487 | #[rustc_intrinsic ] |
2488 | pub const fn ub_checks() -> bool { |
2489 | cfg!(ub_checks) |
2490 | } |
2491 | |
2492 | /// Allocates a block of memory at compile time. |
2493 | /// At runtime, just returns a null pointer. |
2494 | /// |
2495 | /// # Safety |
2496 | /// |
2497 | /// - The `align` argument must be a power of two. |
2498 | /// - At compile time, a compile error occurs if this constraint is violated. |
2499 | /// - At runtime, it is not checked. |
2500 | #[rustc_const_unstable (feature = "const_heap" , issue = "79597" )] |
2501 | #[rustc_nounwind ] |
2502 | #[rustc_intrinsic ] |
2503 | #[miri::intrinsic_fallback_is_spec] |
2504 | pub const unsafe fn const_allocate(_size: usize, _align: usize) -> *mut u8 { |
2505 | // const eval overrides this function, but runtime code for now just returns null pointers. |
2506 | // See <https://github.com/rust-lang/rust/issues/93935>. |
2507 | crate::ptr::null_mut() |
2508 | } |
2509 | |
2510 | /// Deallocates a memory which allocated by `intrinsics::const_allocate` at compile time. |
2511 | /// At runtime, does nothing. |
2512 | /// |
2513 | /// # Safety |
2514 | /// |
2515 | /// - The `align` argument must be a power of two. |
2516 | /// - At compile time, a compile error occurs if this constraint is violated. |
2517 | /// - At runtime, it is not checked. |
2518 | /// - If the `ptr` is created in an another const, this intrinsic doesn't deallocate it. |
2519 | /// - If the `ptr` is pointing to a local variable, this intrinsic doesn't deallocate it. |
2520 | #[rustc_const_unstable (feature = "const_heap" , issue = "79597" )] |
2521 | #[unstable (feature = "core_intrinsics" , issue = "none" )] |
2522 | #[rustc_nounwind ] |
2523 | #[rustc_intrinsic ] |
2524 | #[miri::intrinsic_fallback_is_spec] |
2525 | pub const unsafe fn const_deallocate(_ptr: *mut u8, _size: usize, _align: usize) { |
2526 | // Runtime NOP |
2527 | } |
2528 | |
2529 | /// Returns whether we should perform contract-checking at runtime. |
2530 | /// |
2531 | /// This is meant to be similar to the ub_checks intrinsic, in terms |
2532 | /// of not prematurely commiting at compile-time to whether contract |
2533 | /// checking is turned on, so that we can specify contracts in libstd |
2534 | /// and let an end user opt into turning them on. |
2535 | #[rustc_const_unstable (feature = "contracts_internals" , issue = "128044" /* compiler-team#759 */)] |
2536 | #[unstable (feature = "contracts_internals" , issue = "128044" /* compiler-team#759 */)] |
2537 | #[inline (always)] |
2538 | #[rustc_intrinsic ] |
2539 | pub const fn contract_checks() -> bool { |
2540 | // FIXME: should this be `false` or `cfg!(contract_checks)`? |
2541 | |
2542 | // cfg!(contract_checks) |
2543 | false |
2544 | } |
2545 | |
2546 | /// Check if the pre-condition `cond` has been met. |
2547 | /// |
2548 | /// By default, if `contract_checks` is enabled, this will panic with no unwind if the condition |
2549 | /// returns false. |
2550 | /// |
2551 | /// Note that this function is a no-op during constant evaluation. |
2552 | #[unstable (feature = "contracts_internals" , issue = "128044" )] |
2553 | // Calls to this function get inserted by an AST expansion pass, which uses the equivalent of |
2554 | // `#[allow_internal_unstable]` to allow using `contracts_internals` functions. Const-checking |
2555 | // doesn't honor `#[allow_internal_unstable]`, so for the const feature gate we use the user-facing |
2556 | // `contracts` feature rather than the perma-unstable `contracts_internals` |
2557 | #[rustc_const_unstable (feature = "contracts" , issue = "128044" )] |
2558 | #[lang = "contract_check_requires" ] |
2559 | #[rustc_intrinsic ] |
2560 | pub const fn contract_check_requires<C: Fn() -> bool + Copy>(cond: C) { |
2561 | const_eval_select!( |
2562 | @capture[C: Fn() -> bool + Copy] { cond: C } : |
2563 | if const { |
2564 | // Do nothing |
2565 | } else { |
2566 | if contract_checks() && !cond() { |
2567 | // Emit no unwind panic in case this was a safety requirement. |
2568 | crate::panicking::panic_nounwind("failed requires check" ); |
2569 | } |
2570 | } |
2571 | ) |
2572 | } |
2573 | |
2574 | /// Check if the post-condition `cond` has been met. |
2575 | /// |
2576 | /// By default, if `contract_checks` is enabled, this will panic with no unwind if the condition |
2577 | /// returns false. |
2578 | /// |
2579 | /// Note that this function is a no-op during constant evaluation. |
2580 | #[unstable (feature = "contracts_internals" , issue = "128044" )] |
2581 | // Similar to `contract_check_requires`, we need to use the user-facing |
2582 | // `contracts` feature rather than the perma-unstable `contracts_internals`. |
2583 | // Const-checking doesn't honor allow_internal_unstable logic used by contract expansion. |
2584 | #[rustc_const_unstable (feature = "contracts" , issue = "128044" )] |
2585 | #[lang = "contract_check_ensures" ] |
2586 | #[rustc_intrinsic ] |
2587 | pub const fn contract_check_ensures<C: Fn(&Ret) -> bool + Copy, Ret>(cond: C, ret: Ret) -> Ret { |
2588 | const_eval_select!( |
2589 | @capture[C: Fn(&Ret) -> bool + Copy, Ret] { cond: C, ret: Ret } -> Ret : |
2590 | if const { |
2591 | // Do nothing |
2592 | ret |
2593 | } else { |
2594 | if contract_checks() && !cond(&ret) { |
2595 | // Emit no unwind panic in case this was a safety requirement. |
2596 | crate::panicking::panic_nounwind("failed ensures check" ); |
2597 | } |
2598 | ret |
2599 | } |
2600 | ) |
2601 | } |
2602 | |
2603 | /// The intrinsic will return the size stored in that vtable. |
2604 | /// |
2605 | /// # Safety |
2606 | /// |
2607 | /// `ptr` must point to a vtable. |
2608 | #[rustc_nounwind ] |
2609 | #[unstable (feature = "core_intrinsics" , issue = "none" )] |
2610 | #[rustc_intrinsic ] |
2611 | pub unsafe fn vtable_size(ptr: *const ()) -> usize; |
2612 | |
2613 | /// The intrinsic will return the alignment stored in that vtable. |
2614 | /// |
2615 | /// # Safety |
2616 | /// |
2617 | /// `ptr` must point to a vtable. |
2618 | #[rustc_nounwind ] |
2619 | #[unstable (feature = "core_intrinsics" , issue = "none" )] |
2620 | #[rustc_intrinsic ] |
2621 | pub unsafe fn vtable_align(ptr: *const ()) -> usize; |
2622 | |
2623 | /// The size of a type in bytes. |
2624 | /// |
2625 | /// Note that, unlike most intrinsics, this is safe to call; |
2626 | /// it does not require an `unsafe` block. |
2627 | /// Therefore, implementations must not require the user to uphold |
2628 | /// any safety invariants. |
2629 | /// |
2630 | /// More specifically, this is the offset in bytes between successive |
2631 | /// items of the same type, including alignment padding. |
2632 | /// |
2633 | /// The stabilized version of this intrinsic is [`size_of`]. |
2634 | #[rustc_nounwind ] |
2635 | #[unstable (feature = "core_intrinsics" , issue = "none" )] |
2636 | #[rustc_intrinsic_const_stable_indirect] |
2637 | #[rustc_intrinsic ] |
2638 | pub const fn size_of<T>() -> usize; |
2639 | |
2640 | /// The minimum alignment of a type. |
2641 | /// |
2642 | /// Note that, unlike most intrinsics, this is safe to call; |
2643 | /// it does not require an `unsafe` block. |
2644 | /// Therefore, implementations must not require the user to uphold |
2645 | /// any safety invariants. |
2646 | /// |
2647 | /// The stabilized version of this intrinsic is [`align_of`]. |
2648 | #[rustc_nounwind ] |
2649 | #[unstable (feature = "core_intrinsics" , issue = "none" )] |
2650 | #[rustc_intrinsic_const_stable_indirect] |
2651 | #[rustc_intrinsic ] |
2652 | pub const fn min_align_of<T>() -> usize; |
2653 | |
2654 | /// Returns the number of variants of the type `T` cast to a `usize`; |
2655 | /// if `T` has no variants, returns `0`. Uninhabited variants will be counted. |
2656 | /// |
2657 | /// Note that, unlike most intrinsics, this is safe to call; |
2658 | /// it does not require an `unsafe` block. |
2659 | /// Therefore, implementations must not require the user to uphold |
2660 | /// any safety invariants. |
2661 | /// |
2662 | /// The to-be-stabilized version of this intrinsic is [`crate::mem::variant_count`]. |
2663 | #[rustc_nounwind ] |
2664 | #[unstable (feature = "core_intrinsics" , issue = "none" )] |
2665 | #[rustc_intrinsic ] |
2666 | pub const fn variant_count<T>() -> usize; |
2667 | |
2668 | /// The size of the referenced value in bytes. |
2669 | /// |
2670 | /// The stabilized version of this intrinsic is [`size_of_val`]. |
2671 | /// |
2672 | /// # Safety |
2673 | /// |
2674 | /// See [`crate::mem::size_of_val_raw`] for safety conditions. |
2675 | #[rustc_nounwind ] |
2676 | #[unstable (feature = "core_intrinsics" , issue = "none" )] |
2677 | #[rustc_intrinsic ] |
2678 | #[rustc_intrinsic_const_stable_indirect] |
2679 | pub const unsafe fn size_of_val<T: ?Sized>(ptr: *const T) -> usize; |
2680 | |
2681 | /// The required alignment of the referenced value. |
2682 | /// |
2683 | /// The stabilized version of this intrinsic is [`align_of_val`]. |
2684 | /// |
2685 | /// # Safety |
2686 | /// |
2687 | /// See [`crate::mem::align_of_val_raw`] for safety conditions. |
2688 | #[rustc_nounwind ] |
2689 | #[unstable (feature = "core_intrinsics" , issue = "none" )] |
2690 | #[rustc_intrinsic ] |
2691 | #[rustc_intrinsic_const_stable_indirect] |
2692 | pub const unsafe fn min_align_of_val<T: ?Sized>(ptr: *const T) -> usize; |
2693 | |
2694 | /// Gets a static string slice containing the name of a type. |
2695 | /// |
2696 | /// Note that, unlike most intrinsics, this is safe to call; |
2697 | /// it does not require an `unsafe` block. |
2698 | /// Therefore, implementations must not require the user to uphold |
2699 | /// any safety invariants. |
2700 | /// |
2701 | /// The stabilized version of this intrinsic is [`core::any::type_name`]. |
2702 | #[rustc_nounwind ] |
2703 | #[unstable (feature = "core_intrinsics" , issue = "none" )] |
2704 | #[rustc_intrinsic ] |
2705 | pub const fn type_name<T: ?Sized>() -> &'static str; |
2706 | |
2707 | /// Gets an identifier which is globally unique to the specified type. This |
2708 | /// function will return the same value for a type regardless of whichever |
2709 | /// crate it is invoked in. |
2710 | /// |
2711 | /// Note that, unlike most intrinsics, this is safe to call; |
2712 | /// it does not require an `unsafe` block. |
2713 | /// Therefore, implementations must not require the user to uphold |
2714 | /// any safety invariants. |
2715 | /// |
2716 | /// The stabilized version of this intrinsic is [`core::any::TypeId::of`]. |
2717 | #[rustc_nounwind ] |
2718 | #[unstable (feature = "core_intrinsics" , issue = "none" )] |
2719 | #[rustc_intrinsic ] |
2720 | pub const fn type_id<T: ?Sized + 'static>() -> u128; |
2721 | |
2722 | /// Lowers in MIR to `Rvalue::Aggregate` with `AggregateKind::RawPtr`. |
2723 | /// |
2724 | /// This is used to implement functions like `slice::from_raw_parts_mut` and |
2725 | /// `ptr::from_raw_parts` in a way compatible with the compiler being able to |
2726 | /// change the possible layouts of pointers. |
2727 | #[rustc_nounwind ] |
2728 | #[unstable (feature = "core_intrinsics" , issue = "none" )] |
2729 | #[rustc_intrinsic_const_stable_indirect] |
2730 | #[rustc_intrinsic ] |
2731 | pub const fn aggregate_raw_ptr<P: bounds::BuiltinDeref, D, M>(data: D, meta: M) -> P |
2732 | where |
2733 | <P as bounds::BuiltinDeref>::Pointee: ptr::Pointee<Metadata = M>; |
2734 | |
2735 | /// Lowers in MIR to `Rvalue::UnaryOp` with `UnOp::PtrMetadata`. |
2736 | /// |
2737 | /// This is used to implement functions like `ptr::metadata`. |
2738 | #[rustc_nounwind ] |
2739 | #[unstable (feature = "core_intrinsics" , issue = "none" )] |
2740 | #[rustc_intrinsic_const_stable_indirect] |
2741 | #[rustc_intrinsic ] |
2742 | pub const fn ptr_metadata<P: ptr::Pointee<Metadata = M> + ?Sized, M>(ptr: *const P) -> M; |
2743 | |
2744 | /// This is an accidentally-stable alias to [`ptr::copy_nonoverlapping`]; use that instead. |
2745 | // Note (intentionally not in the doc comment): `ptr::copy_nonoverlapping` adds some extra |
2746 | // debug assertions; if you are writing compiler tests or code inside the standard library |
2747 | // that wants to avoid those debug assertions, directly call this intrinsic instead. |
2748 | #[stable (feature = "rust1" , since = "1.0.0" )] |
2749 | #[rustc_allowed_through_unstable_modules = "import this function via `std::ptr` instead" ] |
2750 | #[rustc_const_stable (feature = "const_intrinsic_copy" , since = "1.83.0" )] |
2751 | #[rustc_nounwind ] |
2752 | #[rustc_intrinsic ] |
2753 | pub const unsafe fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: usize); |
2754 | |
2755 | /// This is an accidentally-stable alias to [`ptr::copy`]; use that instead. |
2756 | // Note (intentionally not in the doc comment): `ptr::copy` adds some extra |
2757 | // debug assertions; if you are writing compiler tests or code inside the standard library |
2758 | // that wants to avoid those debug assertions, directly call this intrinsic instead. |
2759 | #[stable (feature = "rust1" , since = "1.0.0" )] |
2760 | #[rustc_allowed_through_unstable_modules = "import this function via `std::ptr` instead" ] |
2761 | #[rustc_const_stable (feature = "const_intrinsic_copy" , since = "1.83.0" )] |
2762 | #[rustc_nounwind ] |
2763 | #[rustc_intrinsic ] |
2764 | pub const unsafe fn copy<T>(src: *const T, dst: *mut T, count: usize); |
2765 | |
2766 | /// This is an accidentally-stable alias to [`ptr::write_bytes`]; use that instead. |
2767 | // Note (intentionally not in the doc comment): `ptr::write_bytes` adds some extra |
2768 | // debug assertions; if you are writing compiler tests or code inside the standard library |
2769 | // that wants to avoid those debug assertions, directly call this intrinsic instead. |
2770 | #[stable (feature = "rust1" , since = "1.0.0" )] |
2771 | #[rustc_allowed_through_unstable_modules = "import this function via `std::ptr` instead" ] |
2772 | #[rustc_const_stable (feature = "const_intrinsic_copy" , since = "1.83.0" )] |
2773 | #[rustc_nounwind ] |
2774 | #[rustc_intrinsic ] |
2775 | pub const unsafe fn write_bytes<T>(dst: *mut T, val: u8, count: usize); |
2776 | |
2777 | /// Returns the minimum (IEEE 754-2008 minNum) of two `f16` values. |
2778 | /// |
2779 | /// Note that, unlike most intrinsics, this is safe to call; |
2780 | /// it does not require an `unsafe` block. |
2781 | /// Therefore, implementations must not require the user to uphold |
2782 | /// any safety invariants. |
2783 | /// |
2784 | /// The stabilized version of this intrinsic is |
2785 | /// [`f16::min`] |
2786 | #[rustc_nounwind ] |
2787 | #[rustc_intrinsic ] |
2788 | pub const fn minnumf16(x: f16, y: f16) -> f16; |
2789 | |
2790 | /// Returns the minimum (IEEE 754-2008 minNum) of two `f32` values. |
2791 | /// |
2792 | /// Note that, unlike most intrinsics, this is safe to call; |
2793 | /// it does not require an `unsafe` block. |
2794 | /// Therefore, implementations must not require the user to uphold |
2795 | /// any safety invariants. |
2796 | /// |
2797 | /// The stabilized version of this intrinsic is |
2798 | /// [`f32::min`] |
2799 | #[rustc_nounwind ] |
2800 | #[rustc_intrinsic_const_stable_indirect] |
2801 | #[rustc_intrinsic ] |
2802 | pub const fn minnumf32(x: f32, y: f32) -> f32; |
2803 | |
2804 | /// Returns the minimum (IEEE 754-2008 minNum) of two `f64` values. |
2805 | /// |
2806 | /// Note that, unlike most intrinsics, this is safe to call; |
2807 | /// it does not require an `unsafe` block. |
2808 | /// Therefore, implementations must not require the user to uphold |
2809 | /// any safety invariants. |
2810 | /// |
2811 | /// The stabilized version of this intrinsic is |
2812 | /// [`f64::min`] |
2813 | #[rustc_nounwind ] |
2814 | #[rustc_intrinsic_const_stable_indirect] |
2815 | #[rustc_intrinsic ] |
2816 | pub const fn minnumf64(x: f64, y: f64) -> f64; |
2817 | |
2818 | /// Returns the minimum (IEEE 754-2008 minNum) of two `f128` values. |
2819 | /// |
2820 | /// Note that, unlike most intrinsics, this is safe to call; |
2821 | /// it does not require an `unsafe` block. |
2822 | /// Therefore, implementations must not require the user to uphold |
2823 | /// any safety invariants. |
2824 | /// |
2825 | /// The stabilized version of this intrinsic is |
2826 | /// [`f128::min`] |
2827 | #[rustc_nounwind ] |
2828 | #[rustc_intrinsic ] |
2829 | pub const fn minnumf128(x: f128, y: f128) -> f128; |
2830 | |
2831 | /// Returns the minimum (IEEE 754-2019 minimum) of two `f16` values. |
2832 | /// |
2833 | /// Note that, unlike most intrinsics, this is safe to call; |
2834 | /// it does not require an `unsafe` block. |
2835 | /// Therefore, implementations must not require the user to uphold |
2836 | /// any safety invariants. |
2837 | #[rustc_nounwind ] |
2838 | #[rustc_intrinsic ] |
2839 | pub const fn minimumf16(x: f16, y: f16) -> f16 { |
2840 | if x < y { |
2841 | x |
2842 | } else if y < x { |
2843 | y |
2844 | } else if x == y { |
2845 | if x.is_sign_negative() && y.is_sign_positive() { x } else { y } |
2846 | } else { |
2847 | // At least one input is NaN. Use `+` to perform NaN propagation and quieting. |
2848 | x + y |
2849 | } |
2850 | } |
2851 | |
2852 | /// Returns the minimum (IEEE 754-2019 minimum) of two `f32` values. |
2853 | /// |
2854 | /// Note that, unlike most intrinsics, this is safe to call; |
2855 | /// it does not require an `unsafe` block. |
2856 | /// Therefore, implementations must not require the user to uphold |
2857 | /// any safety invariants. |
2858 | #[rustc_nounwind ] |
2859 | #[rustc_intrinsic ] |
2860 | pub const fn minimumf32(x: f32, y: f32) -> f32 { |
2861 | if x < y { |
2862 | x |
2863 | } else if y < x { |
2864 | y |
2865 | } else if x == y { |
2866 | if x.is_sign_negative() && y.is_sign_positive() { x } else { y } |
2867 | } else { |
2868 | // At least one input is NaN. Use `+` to perform NaN propagation and quieting. |
2869 | x + y |
2870 | } |
2871 | } |
2872 | |
2873 | /// Returns the minimum (IEEE 754-2019 minimum) of two `f64` values. |
2874 | /// |
2875 | /// Note that, unlike most intrinsics, this is safe to call; |
2876 | /// it does not require an `unsafe` block. |
2877 | /// Therefore, implementations must not require the user to uphold |
2878 | /// any safety invariants. |
2879 | #[rustc_nounwind ] |
2880 | #[rustc_intrinsic ] |
2881 | pub const fn minimumf64(x: f64, y: f64) -> f64 { |
2882 | if x < y { |
2883 | x |
2884 | } else if y < x { |
2885 | y |
2886 | } else if x == y { |
2887 | if x.is_sign_negative() && y.is_sign_positive() { x } else { y } |
2888 | } else { |
2889 | // At least one input is NaN. Use `+` to perform NaN propagation and quieting. |
2890 | x + y |
2891 | } |
2892 | } |
2893 | |
2894 | /// Returns the minimum (IEEE 754-2019 minimum) of two `f128` values. |
2895 | /// |
2896 | /// Note that, unlike most intrinsics, this is safe to call; |
2897 | /// it does not require an `unsafe` block. |
2898 | /// Therefore, implementations must not require the user to uphold |
2899 | /// any safety invariants. |
2900 | #[rustc_nounwind ] |
2901 | #[rustc_intrinsic ] |
2902 | pub const fn minimumf128(x: f128, y: f128) -> f128 { |
2903 | if x < y { |
2904 | x |
2905 | } else if y < x { |
2906 | y |
2907 | } else if x == y { |
2908 | if x.is_sign_negative() && y.is_sign_positive() { x } else { y } |
2909 | } else { |
2910 | // At least one input is NaN. Use `+` to perform NaN propagation and quieting. |
2911 | x + y |
2912 | } |
2913 | } |
2914 | |
2915 | /// Returns the maximum (IEEE 754-2008 maxNum) of two `f16` values. |
2916 | /// |
2917 | /// Note that, unlike most intrinsics, this is safe to call; |
2918 | /// it does not require an `unsafe` block. |
2919 | /// Therefore, implementations must not require the user to uphold |
2920 | /// any safety invariants. |
2921 | /// |
2922 | /// The stabilized version of this intrinsic is |
2923 | /// [`f16::max`] |
2924 | #[rustc_nounwind ] |
2925 | #[rustc_intrinsic ] |
2926 | pub const fn maxnumf16(x: f16, y: f16) -> f16; |
2927 | |
2928 | /// Returns the maximum (IEEE 754-2008 maxNum) of two `f32` values. |
2929 | /// |
2930 | /// Note that, unlike most intrinsics, this is safe to call; |
2931 | /// it does not require an `unsafe` block. |
2932 | /// Therefore, implementations must not require the user to uphold |
2933 | /// any safety invariants. |
2934 | /// |
2935 | /// The stabilized version of this intrinsic is |
2936 | /// [`f32::max`] |
2937 | #[rustc_nounwind ] |
2938 | #[rustc_intrinsic_const_stable_indirect] |
2939 | #[rustc_intrinsic ] |
2940 | pub const fn maxnumf32(x: f32, y: f32) -> f32; |
2941 | |
2942 | /// Returns the maximum (IEEE 754-2008 maxNum) of two `f64` values. |
2943 | /// |
2944 | /// Note that, unlike most intrinsics, this is safe to call; |
2945 | /// it does not require an `unsafe` block. |
2946 | /// Therefore, implementations must not require the user to uphold |
2947 | /// any safety invariants. |
2948 | /// |
2949 | /// The stabilized version of this intrinsic is |
2950 | /// [`f64::max`] |
2951 | #[rustc_nounwind ] |
2952 | #[rustc_intrinsic_const_stable_indirect] |
2953 | #[rustc_intrinsic ] |
2954 | pub const fn maxnumf64(x: f64, y: f64) -> f64; |
2955 | |
2956 | /// Returns the maximum (IEEE 754-2008 maxNum) of two `f128` values. |
2957 | /// |
2958 | /// Note that, unlike most intrinsics, this is safe to call; |
2959 | /// it does not require an `unsafe` block. |
2960 | /// Therefore, implementations must not require the user to uphold |
2961 | /// any safety invariants. |
2962 | /// |
2963 | /// The stabilized version of this intrinsic is |
2964 | /// [`f128::max`] |
2965 | #[rustc_nounwind ] |
2966 | #[rustc_intrinsic ] |
2967 | pub const fn maxnumf128(x: f128, y: f128) -> f128; |
2968 | |
2969 | /// Returns the maximum (IEEE 754-2019 maximum) of two `f16` values. |
2970 | /// |
2971 | /// Note that, unlike most intrinsics, this is safe to call; |
2972 | /// it does not require an `unsafe` block. |
2973 | /// Therefore, implementations must not require the user to uphold |
2974 | /// any safety invariants. |
2975 | #[rustc_nounwind ] |
2976 | #[rustc_intrinsic ] |
2977 | pub const fn maximumf16(x: f16, y: f16) -> f16 { |
2978 | if x > y { |
2979 | x |
2980 | } else if y > x { |
2981 | y |
2982 | } else if x == y { |
2983 | if x.is_sign_positive() && y.is_sign_negative() { x } else { y } |
2984 | } else { |
2985 | x + y |
2986 | } |
2987 | } |
2988 | |
2989 | /// Returns the maximum (IEEE 754-2019 maximum) of two `f32` values. |
2990 | /// |
2991 | /// Note that, unlike most intrinsics, this is safe to call; |
2992 | /// it does not require an `unsafe` block. |
2993 | /// Therefore, implementations must not require the user to uphold |
2994 | /// any safety invariants. |
2995 | #[rustc_nounwind ] |
2996 | #[rustc_intrinsic ] |
2997 | pub const fn maximumf32(x: f32, y: f32) -> f32 { |
2998 | if x > y { |
2999 | x |
3000 | } else if y > x { |
3001 | y |
3002 | } else if x == y { |
3003 | if x.is_sign_positive() && y.is_sign_negative() { x } else { y } |
3004 | } else { |
3005 | x + y |
3006 | } |
3007 | } |
3008 | |
3009 | /// Returns the maximum (IEEE 754-2019 maximum) of two `f64` values. |
3010 | /// |
3011 | /// Note that, unlike most intrinsics, this is safe to call; |
3012 | /// it does not require an `unsafe` block. |
3013 | /// Therefore, implementations must not require the user to uphold |
3014 | /// any safety invariants. |
3015 | #[rustc_nounwind ] |
3016 | #[rustc_intrinsic ] |
3017 | pub const fn maximumf64(x: f64, y: f64) -> f64 { |
3018 | if x > y { |
3019 | x |
3020 | } else if y > x { |
3021 | y |
3022 | } else if x == y { |
3023 | if x.is_sign_positive() && y.is_sign_negative() { x } else { y } |
3024 | } else { |
3025 | x + y |
3026 | } |
3027 | } |
3028 | |
3029 | /// Returns the maximum (IEEE 754-2019 maximum) of two `f128` values. |
3030 | /// |
3031 | /// Note that, unlike most intrinsics, this is safe to call; |
3032 | /// it does not require an `unsafe` block. |
3033 | /// Therefore, implementations must not require the user to uphold |
3034 | /// any safety invariants. |
3035 | #[rustc_nounwind ] |
3036 | #[rustc_intrinsic ] |
3037 | pub const fn maximumf128(x: f128, y: f128) -> f128 { |
3038 | if x > y { |
3039 | x |
3040 | } else if y > x { |
3041 | y |
3042 | } else if x == y { |
3043 | if x.is_sign_positive() && y.is_sign_negative() { x } else { y } |
3044 | } else { |
3045 | x + y |
3046 | } |
3047 | } |
3048 | |
3049 | /// Returns the absolute value of an `f16`. |
3050 | /// |
3051 | /// The stabilized version of this intrinsic is |
3052 | /// [`f16::abs`](../../std/primitive.f16.html#method.abs) |
3053 | #[rustc_nounwind ] |
3054 | #[rustc_intrinsic ] |
3055 | pub const unsafe fn fabsf16(x: f16) -> f16; |
3056 | |
3057 | /// Returns the absolute value of an `f32`. |
3058 | /// |
3059 | /// The stabilized version of this intrinsic is |
3060 | /// [`f32::abs`](../../std/primitive.f32.html#method.abs) |
3061 | #[rustc_nounwind ] |
3062 | #[rustc_intrinsic_const_stable_indirect] |
3063 | #[rustc_intrinsic ] |
3064 | pub const unsafe fn fabsf32(x: f32) -> f32; |
3065 | |
3066 | /// Returns the absolute value of an `f64`. |
3067 | /// |
3068 | /// The stabilized version of this intrinsic is |
3069 | /// [`f64::abs`](../../std/primitive.f64.html#method.abs) |
3070 | #[rustc_nounwind ] |
3071 | #[rustc_intrinsic_const_stable_indirect] |
3072 | #[rustc_intrinsic ] |
3073 | pub const unsafe fn fabsf64(x: f64) -> f64; |
3074 | |
3075 | /// Returns the absolute value of an `f128`. |
3076 | /// |
3077 | /// The stabilized version of this intrinsic is |
3078 | /// [`f128::abs`](../../std/primitive.f128.html#method.abs) |
3079 | #[rustc_nounwind ] |
3080 | #[rustc_intrinsic ] |
3081 | pub const unsafe fn fabsf128(x: f128) -> f128; |
3082 | |
3083 | /// Copies the sign from `y` to `x` for `f16` values. |
3084 | /// |
3085 | /// The stabilized version of this intrinsic is |
3086 | /// [`f16::copysign`](../../std/primitive.f16.html#method.copysign) |
3087 | #[rustc_nounwind ] |
3088 | #[rustc_intrinsic ] |
3089 | pub const unsafe fn copysignf16(x: f16, y: f16) -> f16; |
3090 | |
3091 | /// Copies the sign from `y` to `x` for `f32` values. |
3092 | /// |
3093 | /// The stabilized version of this intrinsic is |
3094 | /// [`f32::copysign`](../../std/primitive.f32.html#method.copysign) |
3095 | #[rustc_nounwind ] |
3096 | #[rustc_intrinsic_const_stable_indirect] |
3097 | #[rustc_intrinsic ] |
3098 | pub const unsafe fn copysignf32(x: f32, y: f32) -> f32; |
3099 | /// Copies the sign from `y` to `x` for `f64` values. |
3100 | /// |
3101 | /// The stabilized version of this intrinsic is |
3102 | /// [`f64::copysign`](../../std/primitive.f64.html#method.copysign) |
3103 | #[rustc_nounwind ] |
3104 | #[rustc_intrinsic_const_stable_indirect] |
3105 | #[rustc_intrinsic ] |
3106 | pub const unsafe fn copysignf64(x: f64, y: f64) -> f64; |
3107 | |
3108 | /// Copies the sign from `y` to `x` for `f128` values. |
3109 | /// |
3110 | /// The stabilized version of this intrinsic is |
3111 | /// [`f128::copysign`](../../std/primitive.f128.html#method.copysign) |
3112 | #[rustc_nounwind ] |
3113 | #[rustc_intrinsic ] |
3114 | pub const unsafe fn copysignf128(x: f128, y: f128) -> f128; |
3115 | |
3116 | /// Inform Miri that a given pointer definitely has a certain alignment. |
3117 | #[cfg (miri)] |
3118 | #[rustc_allow_const_fn_unstable (const_eval_select)] |
3119 | pub(crate) const fn miri_promise_symbolic_alignment(ptr: *const (), align: usize) { |
3120 | unsafe extern "Rust" { |
3121 | /// Miri-provided extern function to promise that a given pointer is properly aligned for |
3122 | /// "symbolic" alignment checks. Will fail if the pointer is not actually aligned or `align` is |
3123 | /// not a power of two. Has no effect when alignment checks are concrete (which is the default). |
3124 | unsafefn miri_promise_symbolic_alignment(ptr: *const (), align: usize); |
3125 | } |
3126 | |
3127 | const_eval_select!( |
3128 | @capture { ptr: *const (), align: usize}: |
3129 | if const { |
3130 | // Do nothing. |
3131 | } else { |
3132 | // SAFETY: this call is always safe. |
3133 | unsafe { |
3134 | miri_promise_symbolic_alignment(ptr, align); |
3135 | } |
3136 | } |
3137 | ) |
3138 | } |
3139 | |