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_char_convert)]
 109 #![feature(const_discriminant)]
 110 #![feature(const_eval_select)]
 111 #![feature(const_float_bits_conv)]
 112 #![feature(const_float_classify)]
 113 #![feature(const_fmt_arguments_new)]
 114 #![feature(const_heap)]
 115 #![feature(const_inherent_unchecked_arith)]
 116 #![feature(const_int_unchecked_arith)]
 117 #![feature(const_intrinsic_copy)]
 118 #![feature(const_intrinsic_forget)]
 119 #![feature(const_likely)]
 120 #![feature(const_maybe_uninit_as_ptr)]
 121 #![feature(const_maybe_uninit_assume_init)]
 122 #![feature(const_num_from_num)]
 123 #![feature(const_ops)]
 124 #![feature(const_option)]
 125 #![feature(const_pin)]
 126 #![feature(const_replace)]
 127 #![feature(const_ptr_offset)]
 128 #![feature(const_ptr_offset_from)]
 129 #![feature(const_ptr_read)]
 130 #![feature(const_ptr_write)]
 131 #![feature(const_raw_ptr_comparison)]
 132 #![feature(const_size_of_val)]
 133 #![feature(const_slice_from_raw_parts)]
 134 #![feature(const_slice_ptr_len)]
 135 #![feature(const_str_from_utf8_unchecked_mut)]
 136 #![feature(const_swap)]
 137 #![feature(const_trait_impl)]
 138 #![feature(const_type_id)]
 139 #![feature(const_type_name)]
 140 #![feature(const_default_impls)]
 141 #![feature(duration_consts_2)]
 142 #![feature(ptr_metadata)]
 143 #![feature(slice_ptr_get)]
 144 #![feature(str_internals)]
 145 #![feature(variant_count)]
 146 #![feature(const_array_from_ref)]
 147 #![feature(const_slice_from_ref)]
 148 //
 149 // Language features:
 150 #![feature(abi_unadjusted)]
 151 #![feature(allow_internal_unsafe)]
 152 #![feature(allow_internal_unstable)]
 153 #![feature(asm)]
 154 #![feature(associated_type_bounds)]
 155 #![feature(auto_traits)]
 156 #![feature(cfg_target_has_atomic)]
 157 #![feature(const_fn_floating_point_arithmetic)]
 158 #![feature(const_fn_fn_ptr_basics)]
 159 #![feature(const_fn_trait_bound)]
 160 #![feature(const_impl_trait)]
 161 #![feature(const_mut_refs)]
 162 #![feature(const_precise_live_drops)]
 163 #![cfg_attr(bootstrap, feature(const_raw_ptr_deref))]
 164 #![feature(const_refs_to_cell)]
 165 #![feature(decl_macro)]
 166 #![feature(doc_cfg)]
 167 #![feature(doc_notable_trait)]
 168 #![feature(doc_primitive)]
 169 #![feature(exhaustive_patterns)]
 170 #![feature(doc_cfg_hide)]
 171 #![feature(extern_types)]
 172 #![feature(fundamental)]
 173 #![feature(if_let_guard)]
 174 #![feature(intra_doc_pointers)]
 175 #![feature(intrinsics)]
 176 #![feature(lang_items)]
 177 #![feature(link_llvm_intrinsics)]
 178 #![feature(llvm_asm)]
 179 #![feature(min_specialization)]
 180 #![feature(mixed_integer_ops)]
 181 #![feature(must_not_suspend)]
 182 #![feature(negative_impls)]
 183 #![feature(never_type)]
 184 #![feature(no_core)]
 185 #![feature(no_coverage)] // rust-lang/rust#84605
 186 #![feature(no_niche)] // rust-lang/rust#68303
 187 #![feature(platform_intrinsics)]
 188 #![feature(prelude_import)]
 189 #![feature(repr_simd)]
 190 #![feature(rustc_allow_const_fn_unstable)]
 191 #![feature(rustc_attrs)]
 192 #![feature(simd_ffi)]
 193 #![feature(staged_api)]
 194 #![feature(stmt_expr_attributes)]
 195 #![feature(trait_alias)]
 196 #![feature(transparent_unions)]
 197 #![feature(try_blocks)]
 198 #![feature(unboxed_closures)]
 199 #![feature(unsized_fn_params)]
 200 #![cfg_attr(not(bootstrap), feature(asm_const))]
 201 //
 202 // Target features:
 203 #![feature(aarch64_target_feature)]
 204 #![feature(adx_target_feature)]
 205 #![feature(arm_target_feature)]
 206 #![feature(avx512_target_feature)]
 207 #![feature(cmpxchg16b_target_feature)]
 208 #![feature(f16c_target_feature)]
 209 #![feature(hexagon_target_feature)]
 210 #![feature(mips_target_feature)]
 211 #![feature(powerpc_target_feature)]
 212 #![feature(rtm_target_feature)]
 213 #![feature(sse4a_target_feature)]
 214 #![feature(tbm_target_feature)]
 215 #![feature(wasm_target_feature)]
 216
 217 // allow using `core::` in intra-doc links
 218 #[allow(unused_extern_crates)]
 219 extern crate self as core;
 220
 221 #[prelude_import]
 222 #[allow(unused)]
 223 use prelude::v1::*;
 224
 225 #[cfg(not(test))] // See #65860
 226 #[macro_use]
 227 mod macros;
 228
 229 // We don't export this through #[macro_export] for now, to avoid breakage.
 230 // See https://github.com/rust-lang/rust/issues/82913
 231 #[cfg(not(test))]
 232 #[unstable(feature = "assert_matches", issue = "82775")]
 233 /// Unstable module containing the unstable `assert_matches` macro.
 234 pub mod assert_matches {
 235     #[unstable(feature = "assert_matches", issue = "82775")]
 236     pub use crate::macros::{assert_matches, debug_assert_matches};
 237 }
 238
 239 #[macro_use]
 240 mod internal_macros;
 241
 242 #[path = "num/shells/int_macros.rs"]
 243 #[macro_use]
 244 mod int_macros;
 245
 246 #[path = "num/shells/i128.rs"]
 247 pub mod i128;
 248 #[path = "num/shells/i16.rs"]
 249 pub mod i16;
 250 #[path = "num/shells/i32.rs"]
 251 pub mod i32;
 252 #[path = "num/shells/i64.rs"]
 253 pub mod i64;
 254 #[path = "num/shells/i8.rs"]
 255 pub mod i8;
 256 #[path = "num/shells/isize.rs"]
 257 pub mod isize;
 258
 259 #[path = "num/shells/u128.rs"]
 260 pub mod u128;
 261 #[path = "num/shells/u16.rs"]
 262 pub mod u16;
 263 #[path = "num/shells/u32.rs"]
 264 pub mod u32;
 265 #[path = "num/shells/u64.rs"]
 266 pub mod u64;
 267 #[path = "num/shells/u8.rs"]
 268 pub mod u8;
 269 #[path = "num/shells/usize.rs"]
 270 pub mod usize;
 271
 272 #[path = "num/f32.rs"]
 273 pub mod f32;
 274 #[path = "num/f64.rs"]
 275 pub mod f64;
 276
 277 #[macro_use]
 278 pub mod num;
 279
 280 /* The libcore prelude, not as all-encompassing as the libstd prelude */
 281
 282 pub mod prelude;
 283
 284 /* Core modules for ownership management */
 285
 286 pub mod hint;
 287 pub mod intrinsics;
 288 pub mod mem;
 289 pub mod ptr;
 290
 291 /* Core language traits */
 292
 293 pub mod borrow;
 294 pub mod clone;
 295 pub mod cmp;
 296 pub mod convert;
 297 pub mod default;
 298 pub mod marker;
 299 pub mod ops;
 300
 301 /* Core types and methods on primitives */
 302
 303 pub mod any;
 304 pub mod array;
 305 pub mod ascii;
 306 pub mod cell;
 307 pub mod char;
 308 pub mod ffi;
 309 pub mod iter;
 310 #[unstable(feature = "once_cell", issue = "74465")]
 311 pub mod lazy;
 312 pub mod option;
 313 pub mod panic;
 314 pub mod panicking;
 315 pub mod pin;
 316 pub mod result;
 317 #[unstable(feature = "async_stream", issue = "79024")]
 318 pub mod stream;
 319 pub mod sync;
 320
 321 pub mod fmt;
 322 pub mod hash;
 323 pub mod slice;
 324 pub mod str;
 325 pub mod time;
 326
 327 pub mod unicode;
 328
 329 /* Async */
 330 pub mod future;
 331 pub mod task;
 332
 333 /* Heap memory allocator trait */
 334 #[allow(missing_docs)]
 335 pub mod alloc;
 336
 337 // note: does not need to be public
 338 mod bool;
 339 mod tuple;
 340 mod unit;
 341
 342 #[stable(feature = "core_primitive", since = "1.43.0")]
 343 pub mod primitive;
 344
 345 // Pull in the `core_arch` crate directly into libcore. The contents of
 346 // `core_arch` are in a different repository: rust-lang/stdarch.
 347 //
 348 // `core_arch` depends on libcore, but the contents of this module are
 349 // set up in such a way that directly pulling it here works such that the
 350 // crate uses the this crate as its libcore.
 351 #[path = "../../stdarch/crates/core_arch/src/mod.rs"]
 352 #[allow(
 353     missing_docs,
 354     missing_debug_implementations,
 355     dead_code,
 356     unused_imports,
 357     unsafe_op_in_unsafe_fn
 358 )]
 359 #[allow(rustdoc::bare_urls)]
 360 // FIXME: This annotation should be moved into rust-lang/stdarch after clashing_extern_declarations is
 361 // merged. It currently cannot because bootstrap fails as the lint hasn't been defined yet.
 362 #[allow(clashing_extern_declarations)]
 363 #[unstable(feature = "stdsimd", issue = "48556")]
 364 mod core_arch;
 365
 366 #[doc = include_str!("../../stdarch/crates/core_arch/src/core_arch_docs.md")]
 367 #[stable(feature = "simd_arch", since = "1.27.0")]
 368 pub mod arch {
 369     #[stable(feature = "simd_arch", since = "1.27.0")]
 370     pub use crate::core_arch::arch::*;
 371
 372     /// Inline assembly.
 373     ///
 374     /// Read the [unstable book] for the usage.
 375     ///
 376     /// [unstable book]: ../../unstable-book/library-features/asm.html
 377     #[unstable(
 378         feature = "asm",
 379         issue = "72016",
 380         reason = "inline assembly is not stable enough for use and is subject to change"
 381     )]
 382     #[rustc_builtin_macro]
 383     pub macro asm("assembly template", $(operands,)* $(options($(option),*))?) {
 384         /* compiler built-in */
 385     }
 386
 387     /// Module-level inline assembly.
 388     #[unstable(
 389         feature = "global_asm",
 390         issue = "35119",
 391         reason = "`global_asm!` is not stable enough for use and is subject to change"
 392     )]
 393     #[rustc_builtin_macro]
 394     pub macro global_asm("assembly template", $(operands,)* $(options($(option),*))?) {
 395         /* compiler built-in */
 396     }
 397 }
 398
 399 // Pull in the `core_simd` crate directly into libcore. The contents of
 400 // `core_simd` are in a different repository: rust-lang/portable-simd.
 401 //
 402 // `core_simd` depends on libcore, but the contents of this module are
 403 // set up in such a way that directly pulling it here works such that the
 404 // crate uses this crate as its libcore.
 405 #[path = "../../portable-simd/crates/core_simd/src/mod.rs"]
 406 #[allow(missing_debug_implementations, dead_code, unsafe_op_in_unsafe_fn, unused_unsafe)]
 407 #[allow(rustdoc::bare_urls)]
 408 #[unstable(feature = "portable_simd", issue = "86656")]
 409 #[cfg(not(all(miri, doctest)))] // Miri does not support all SIMD intrinsics
 410 #[cfg(not(bootstrap))]
 411 mod core_simd;
 412
 413 #[doc = include_str!("../../portable-simd/crates/core_simd/src/core_simd_docs.md")]
 414 #[unstable(feature = "portable_simd", issue = "86656")]
 415 #[cfg(not(all(miri, doctest)))] // Miri does not support all SIMD intrinsics
 416 #[cfg(not(bootstrap))]
 417 pub mod simd {
 418     #[unstable(feature = "portable_simd", issue = "86656")]
 419     pub use crate::core_simd::simd::*;
 420 }
 421
 422 include!("primitive_docs.rs");