library/core/src/lib.rs

   1 //! # The Rust Core Library
   2 //!
   3 //! The Rust Core Library is the dependency-free[^free] foundation of [The
   4 //! Rust Standard Library](../std/index.html). It is the portable glue
   5 //! between the language and its libraries, defining the intrinsic and
   6 //! primitive building blocks of all Rust code. It links to no
   7 //! upstream libraries, no system libraries, and no libc.
   8 //!
   9 //! [^free]: Strictly speaking, there are some symbols which are needed but
  10 //!          they aren't always necessary.
  11 //!
  12 //! The core library is *minimal*: it isn't even aware of heap allocation,
  13 //! nor does it provide concurrency or I/O. These things require
  14 //! platform integration, and this library is platform-agnostic.
  15 //!
  16 //! # How to use the core library
  17 //!
  18 //! Please note that all of these details are currently not considered stable.
  19 //!
  20 // FIXME: Fill me in with more detail when the interface settles
  21 //! This library is built on the assumption of a few existing symbols:
  22 //!
  23 //! * `memcpy`, `memcmp`, `memset` - These are core memory routines which are
  24 //!   often generated by LLVM. Additionally, this library can make explicit
  25 //!   calls to these functions. Their signatures are the same as found in C.
  26 //!   These functions are often provided by the system libc, but can also be
  27 //!   provided by the [compiler-builtins crate](https://crates.io/crates/compiler_builtins).
  28 //!
  29 //! * `rust_begin_panic` - This function takes four arguments, a
  30 //!   `fmt::Arguments`, a `&'static str`, and two `u32`'s. These four arguments
  31 //!   dictate the panic message, the file at which panic was invoked, and the
  32 //!   line and column inside the file. It is up to consumers of this core
  33 //!   library to define this panic function; it is only required to never
  34 //!   return. This requires a `lang` attribute named `panic_impl`.
  35 //!
  36 //! * `rust_eh_personality` - is used by the failure mechanisms of the
  37 //!    compiler. This is often mapped to GCC's personality function, but crates
  38 //!    which do not trigger a panic can be assured that this function is never
  39 //!    called. The `lang` attribute is called `eh_personality`.
  40
  41 // Since libcore defines many fundamental lang items, all tests live in a
  42 // separate crate, libcoretest, to avoid bizarre issues.
  43 //
  44 // Here we explicitly #[cfg]-out this whole crate when testing. If we don't do
  45 // this, both the generated test artifact and the linked libtest (which
  46 // transitively includes libcore) will both define the same set of lang items,
  47 // and this will cause the E0152 "found duplicate lang item" error. See
  48 // discussion in #50466 for details.
  49 //
  50 // This cfg won't affect doc tests.
  51 #![cfg(not(test))]
  52 // To run libcore tests without x.py without ending up with two copies of libcore, Miri needs to be
  53 // able to "empty" this crate. See <https://github.com/rust-lang/miri-test-libstd/issues/4>.
  54 // rustc itself never sets the feature, so this line has no affect there.
  55 #![cfg(any(not(feature = "miri-test-libstd"), test, doctest))]
  56 #![stable(feature = "core", since = "1.6.0")]
  57 #![doc(
  58     html_playground_url = "https://play.rust-lang.org/",
  59     issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
  60     test(no_crate_inject, attr(deny(warnings))),
  61     test(attr(allow(dead_code, deprecated, unused_variables, unused_mut)))
  62 )]
  63 #![cfg_attr(
  64     not(bootstrap),
  65     doc(cfg_hide(
  66         not(test),
  67         any(not(feature = "miri-test-libstd"), test, doctest),
  68         no_fp_fmt_parse,
  69         target_pointer_width = "16",
  70         target_pointer_width = "32",
  71         target_pointer_width = "64",
  72         target_has_atomic = "8",
  73         target_has_atomic = "16",
  74         target_has_atomic = "32",
  75         target_has_atomic = "64",
  76         target_has_atomic = "ptr",
  77         target_has_atomic_equal_alignment = "8",
  78         target_has_atomic_equal_alignment = "16",
  79         target_has_atomic_equal_alignment = "32",
  80         target_has_atomic_equal_alignment = "64",
  81         target_has_atomic_equal_alignment = "ptr",
  82         target_has_atomic_load_store = "8",
  83         target_has_atomic_load_store = "16",
  84         target_has_atomic_load_store = "32",
  85         target_has_atomic_load_store = "64",
  86         target_has_atomic_load_store = "ptr",
  87     ))
  88 )]
  89 #![no_core]
  90 //
  91 // Lints:
  92 #![deny(rust_2021_incompatible_or_patterns)]
  93 #![deny(unsafe_op_in_unsafe_fn)]
  94 #![warn(deprecated_in_future)]
  95 #![warn(missing_debug_implementations)]
  96 #![warn(missing_docs)]
  97 #![allow(explicit_outlives_requirements)]
  98 //
  99 // Library features for const fns:
 100 #![feature(const_align_offset)]
 101 #![feature(const_align_of_val)]
 102 #![feature(const_alloc_layout)]
 103 #![feature(const_arguments_as_str)]
 104 #![feature(const_assert_type)]
 105 #![feature(const_bigint_helper_methods)]
 106 #![feature(const_caller_location)]
 107 #![feature(const_cell_into_inner)]
 108 #![feature(const_discriminant)]
 109 #![feature(const_eval_select)]
 110 #![feature(const_float_bits_conv)]
 111 #![feature(const_float_classify)]
 112 #![feature(const_fmt_arguments_new)]
 113 #![feature(const_heap)]
 114 #![feature(const_inherent_unchecked_arith)]
 115 #![feature(const_int_unchecked_arith)]
 116 #![feature(const_intrinsic_copy)]
 117 #![feature(const_intrinsic_forget)]
 118 #![feature(const_likely)]
 119 #![feature(const_maybe_uninit_as_ptr)]
 120 #![feature(const_maybe_uninit_assume_init)]
 121 #![feature(const_num_from_num)]
 122 #![feature(const_ops)]
 123 #![feature(const_option)]
 124 #![feature(const_pin)]
 125 #![feature(const_replace)]
 126 #![feature(const_ptr_offset)]
 127 #![feature(const_ptr_offset_from)]
 128 #![feature(const_ptr_read)]
 129 #![feature(const_ptr_write)]
 130 #![feature(const_raw_ptr_comparison)]
 131 #![feature(const_size_of_val)]
 132 #![feature(const_slice_from_raw_parts)]
 133 #![feature(const_slice_ptr_len)]
 134 #![feature(const_str_from_utf8_unchecked_mut)]
 135 #![feature(const_swap)]
 136 #![feature(const_trait_impl)]
 137 #![feature(const_type_id)]
 138 #![feature(const_type_name)]
 139 #![feature(const_default_impls)]
 140 #![feature(duration_consts_2)]
 141 #![feature(ptr_metadata)]
 142 #![feature(slice_ptr_get)]
 143 #![feature(str_internals)]
 144 #![feature(variant_count)]
 145 #![feature(const_array_from_ref)]
 146 #![feature(const_slice_from_ref)]
 147 //
 148 // Language features:
 149 #![feature(abi_unadjusted)]
 150 #![feature(allow_internal_unsafe)]
 151 #![feature(allow_internal_unstable)]
 152 #![feature(asm)]
 153 #![feature(associated_type_bounds)]
 154 #![feature(auto_traits)]
 155 #![feature(cfg_target_has_atomic)]
 156 #![feature(const_fn_floating_point_arithmetic)]
 157 #![feature(const_fn_fn_ptr_basics)]
 158 #![feature(const_fn_trait_bound)]
 159 #![feature(const_impl_trait)]
 160 #![feature(const_mut_refs)]
 161 #![feature(const_precise_live_drops)]
 162 #![cfg_attr(bootstrap, feature(const_raw_ptr_deref))]
 163 #![feature(const_refs_to_cell)]
 164 #![feature(decl_macro)]
 165 #![feature(doc_cfg)]
 166 #![feature(doc_notable_trait)]
 167 #![feature(doc_primitive)]
 168 #![feature(exhaustive_patterns)]
 169 #![feature(doc_cfg_hide)]
 170 #![feature(extern_types)]
 171 #![feature(fundamental)]
 172 #![feature(if_let_guard)]
 173 #![feature(intra_doc_pointers)]
 174 #![feature(intrinsics)]
 175 #![feature(lang_items)]
 176 #![feature(link_llvm_intrinsics)]
 177 #![feature(llvm_asm)]
 178 #![feature(min_specialization)]
 179 #![feature(mixed_integer_ops)]
 180 #![feature(must_not_suspend)]
 181 #![feature(negative_impls)]
 182 #![feature(never_type)]
 183 #![feature(no_core)]
 184 #![feature(no_coverage)] // rust-lang/rust#84605
 185 #![feature(no_niche)] // rust-lang/rust#68303
 186 #![feature(platform_intrinsics)]
 187 #![feature(prelude_import)]
 188 #![feature(repr_simd)]
 189 #![feature(rustc_allow_const_fn_unstable)]
 190 #![feature(rustc_attrs)]
 191 #![feature(simd_ffi)]
 192 #![feature(staged_api)]
 193 #![feature(stmt_expr_attributes)]
 194 #![feature(trait_alias)]
 195 #![feature(transparent_unions)]
 196 #![feature(try_blocks)]
 197 #![feature(unboxed_closures)]
 198 #![feature(unsized_fn_params)]
 199 #![cfg_attr(not(bootstrap), feature(asm_const))]
 200 //
 201 // Target features:
 202 #![feature(aarch64_target_feature)]
 203 #![feature(adx_target_feature)]
 204 #![feature(arm_target_feature)]
 205 #![feature(avx512_target_feature)]
 206 #![feature(cmpxchg16b_target_feature)]
 207 #![feature(f16c_target_feature)]
 208 #![feature(hexagon_target_feature)]
 209 #![feature(mips_target_feature)]
 210 #![feature(powerpc_target_feature)]
 211 #![feature(rtm_target_feature)]
 212 #![feature(sse4a_target_feature)]
 213 #![feature(tbm_target_feature)]
 214 #![feature(wasm_target_feature)]
 215
 216 // allow using `core::` in intra-doc links
 217 #[allow(unused_extern_crates)]
 218 extern crate self as core;
 219
 220 #[prelude_import]
 221 #[allow(unused)]
 222 use prelude::v1::*;
 223
 224 #[cfg(not(test))] // See #65860
 225 #[macro_use]
 226 mod macros;
 227
 228 // We don't export this through #[macro_export] for now, to avoid breakage.
 229 // See https://github.com/rust-lang/rust/issues/82913
 230 #[cfg(not(test))]
 231 #[unstable(feature = "assert_matches", issue = "82775")]
 232 /// Unstable module containing the unstable `assert_matches` macro.
 233 pub mod assert_matches {
 234     #[unstable(feature = "assert_matches", issue = "82775")]
 235     pub use crate::macros::{assert_matches, debug_assert_matches};
 236 }
 237
 238 #[macro_use]
 239 mod internal_macros;
 240
 241 #[path = "num/shells/int_macros.rs"]
 242 #[macro_use]
 243 mod int_macros;
 244
 245 #[path = "num/shells/i128.rs"]
 246 pub mod i128;
 247 #[path = "num/shells/i16.rs"]
 248 pub mod i16;
 249 #[path = "num/shells/i32.rs"]
 250 pub mod i32;
 251 #[path = "num/shells/i64.rs"]
 252 pub mod i64;
 253 #[path = "num/shells/i8.rs"]
 254 pub mod i8;
 255 #[path = "num/shells/isize.rs"]
 256 pub mod isize;
 257
 258 #[path = "num/shells/u128.rs"]
 259 pub mod u128;
 260 #[path = "num/shells/u16.rs"]
 261 pub mod u16;
 262 #[path = "num/shells/u32.rs"]
 263 pub mod u32;
 264 #[path = "num/shells/u64.rs"]
 265 pub mod u64;
 266 #[path = "num/shells/u8.rs"]
 267 pub mod u8;
 268 #[path = "num/shells/usize.rs"]
 269 pub mod usize;
 270
 271 #[path = "num/f32.rs"]
 272 pub mod f32;
 273 #[path = "num/f64.rs"]
 274 pub mod f64;
 275
 276 #[macro_use]
 277 pub mod num;
 278
 279 /* The libcore prelude, not as all-encompassing as the libstd prelude */
 280
 281 pub mod prelude;
 282
 283 /* Core modules for ownership management */
 284
 285 pub mod hint;
 286 pub mod intrinsics;
 287 pub mod mem;
 288 pub mod ptr;
 289
 290 /* Core language traits */
 291
 292 pub mod borrow;
 293 pub mod clone;
 294 pub mod cmp;
 295 pub mod convert;
 296 pub mod default;
 297 pub mod marker;
 298 pub mod ops;
 299
 300 /* Core types and methods on primitives */
 301
 302 pub mod any;
 303 pub mod array;
 304 pub mod ascii;
 305 pub mod cell;
 306 pub mod char;
 307 pub mod ffi;
 308 pub mod iter;
 309 #[unstable(feature = "once_cell", issue = "74465")]
 310 pub mod lazy;
 311 pub mod option;
 312 pub mod panic;
 313 pub mod panicking;
 314 pub mod pin;
 315 pub mod result;
 316 #[unstable(feature = "async_stream", issue = "79024")]
 317 pub mod stream;
 318 pub mod sync;
 319
 320 pub mod fmt;
 321 pub mod hash;
 322 pub mod slice;
 323 pub mod str;
 324 pub mod time;
 325
 326 pub mod unicode;
 327
 328 /* Async */
 329 pub mod future;
 330 pub mod task;
 331
 332 /* Heap memory allocator trait */
 333 #[allow(missing_docs)]
 334 pub mod alloc;
 335
 336 // note: does not need to be public
 337 mod bool;
 338 mod tuple;
 339 mod unit;
 340
 341 #[stable(feature = "core_primitive", since = "1.43.0")]
 342 pub mod primitive;
 343
 344 // Pull in the `core_arch` crate directly into libcore. The contents of
 345 // `core_arch` are in a different repository: rust-lang/stdarch.
 346 //
 347 // `core_arch` depends on libcore, but the contents of this module are
 348 // set up in such a way that directly pulling it here works such that the
 349 // crate uses the this crate as its libcore.
 350 #[path = "../../stdarch/crates/core_arch/src/mod.rs"]
 351 #[allow(
 352     missing_docs,
 353     missing_debug_implementations,
 354     dead_code,
 355     unused_imports,
 356     unsafe_op_in_unsafe_fn
 357 )]
 358 #[allow(rustdoc::bare_urls)]
 359 // FIXME: This annotation should be moved into rust-lang/stdarch after clashing_extern_declarations is
 360 // merged. It currently cannot because bootstrap fails as the lint hasn't been defined yet.
 361 #[allow(clashing_extern_declarations)]
 362 #[unstable(feature = "stdsimd", issue = "48556")]
 363 mod core_arch;
 364
 365 #[doc = include_str!("../../stdarch/crates/core_arch/src/core_arch_docs.md")]
 366 #[stable(feature = "simd_arch", since = "1.27.0")]
 367 pub mod arch {
 368     #[stable(feature = "simd_arch", since = "1.27.0")]
 369     pub use crate::core_arch::arch::*;
 370
 371     /// Inline assembly.
 372     ///
 373     /// Read the [unstable book] for the usage.
 374     ///
 375     /// [unstable book]: ../../unstable-book/library-features/asm.html
 376     #[unstable(
 377         feature = "asm",
 378         issue = "72016",
 379         reason = "inline assembly is not stable enough for use and is subject to change"
 380     )]
 381     #[rustc_builtin_macro]
 382     pub macro asm("assembly template", $(operands,)* $(options($(option),*))?) {
 383         /* compiler built-in */
 384     }
 385
 386     /// Module-level inline assembly.
 387     #[unstable(
 388         feature = "global_asm",
 389         issue = "35119",
 390         reason = "`global_asm!` is not stable enough for use and is subject to change"
 391     )]
 392     #[rustc_builtin_macro]
 393     pub macro global_asm("assembly template", $(operands,)* $(options($(option),*))?) {
 394         /* compiler built-in */
 395     }
 396 }
 397
 398 // Pull in the `core_simd` crate directly into libcore. The contents of
 399 // `core_simd` are in a different repository: rust-lang/portable-simd.
 400 //
 401 // `core_simd` depends on libcore, but the contents of this module are
 402 // set up in such a way that directly pulling it here works such that the
 403 // crate uses this crate as its libcore.
 404 #[path = "../../portable-simd/crates/core_simd/src/mod.rs"]
 405 #[allow(missing_debug_implementations, dead_code, unsafe_op_in_unsafe_fn, unused_unsafe)]
 406 #[allow(rustdoc::bare_urls)]
 407 #[unstable(feature = "portable_simd", issue = "86656")]
 408 #[cfg(not(all(miri, doctest)))] // Miri does not support all SIMD intrinsics
 409 #[cfg(not(bootstrap))]
 410 mod core_simd;
 411
 412 #[doc = include_str!("../../portable-simd/crates/core_simd/src/core_simd_docs.md")]
 413 #[unstable(feature = "portable_simd", issue = "86656")]
 414 #[cfg(not(all(miri, doctest)))] // Miri does not support all SIMD intrinsics
 415 #[cfg(not(bootstrap))]
 416 pub mod simd {
 417     #[unstable(feature = "portable_simd", issue = "86656")]
 418     pub use crate::core_simd::simd::*;
 419 }
 420
 421 include!("primitive_docs.rs");