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 #![stable(feature = "core", since = "1.6.0")]
  53 #![doc(
  54     html_root_url = "https://doc.rust-lang.org/nightly/",
  55     html_playground_url = "https://play.rust-lang.org/",
  56     issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
  57     test(no_crate_inject, attr(deny(warnings))),
  58     test(attr(allow(dead_code, deprecated, unused_variables, unused_mut)))
  59 )]
  60 #![no_core]
  61 #![warn(deprecated_in_future)]
  62 #![warn(missing_docs)]
  63 #![warn(missing_debug_implementations)]
  64 #![allow(explicit_outlives_requirements)]
  65 #![allow(incomplete_features)]
  66 #![feature(allow_internal_unstable)]
  67 #![feature(arbitrary_self_types)]
  68 #![feature(asm)]
  69 #![feature(bound_cloned)]
  70 #![feature(cfg_target_has_atomic)]
  71 #![feature(concat_idents)]
  72 #![feature(const_alloc_layout)]
  73 #![feature(const_discriminant)]
  74 #![feature(const_checked_int_methods)]
  75 #![feature(const_euclidean_int_methods)]
  76 #![feature(const_overflowing_int_methods)]
  77 #![feature(const_int_unchecked_arith)]
  78 #![feature(const_int_pow)]
  79 #![feature(constctlz)]
  80 #![feature(const_panic)]
  81 #![feature(const_fn_union)]
  82 #![feature(const_generics)]
  83 #![feature(const_option)]
  84 #![feature(const_precise_live_drops)]
  85 #![feature(const_ptr_offset)]
  86 #![feature(const_ptr_offset_from)]
  87 #![feature(const_raw_ptr_comparison)]
  88 #![feature(const_result)]
  89 #![feature(const_slice_from_raw_parts)]
  90 #![feature(const_slice_ptr_len)]
  91 #![feature(const_size_of_val)]
  92 #![feature(const_align_of_val)]
  93 #![feature(const_type_name)]
  94 #![feature(const_likely)]
  95 #![feature(const_unreachable_unchecked)]
  96 #![feature(custom_inner_attributes)]
  97 #![feature(decl_macro)]
  98 #![feature(doc_cfg)]
  99 #![cfg_attr(not(bootstrap), feature(doc_spotlight))]
 100 #![feature(duration_consts_2)]
 101 #![feature(extern_types)]
 102 #![feature(fundamental)]
 103 #![feature(intrinsics)]
 104 #![feature(try_find)]
 105 #![feature(is_sorted)]
 106 #![feature(lang_items)]
 107 #![feature(link_llvm_intrinsics)]
 108 #![feature(llvm_asm)]
 109 #![feature(negative_impls)]
 110 #![feature(never_type)]
 111 #![feature(nll)]
 112 #![feature(exhaustive_patterns)]
 113 #![feature(no_core)]
 114 #![feature(optin_builtin_traits)]
 115 #![feature(or_patterns)]
 116 #![feature(prelude_import)]
 117 #![feature(repr_simd, platform_intrinsics)]
 118 #![feature(rustc_attrs)]
 119 #![feature(simd_ffi)]
 120 #![feature(specialization)]
 121 #![feature(staged_api)]
 122 #![feature(std_internals)]
 123 #![feature(stmt_expr_attributes)]
 124 #![feature(transparent_unions)]
 125 #![feature(unboxed_closures)]
 126 #![feature(unsized_locals)]
 127 #![feature(untagged_unions)]
 128 #![feature(unwind_attributes)]
 129 #![feature(variant_count)]
 130 #![feature(doc_alias)]
 131 #![feature(mmx_target_feature)]
 132 #![feature(tbm_target_feature)]
 133 #![feature(sse4a_target_feature)]
 134 #![feature(arm_target_feature)]
 135 #![feature(powerpc_target_feature)]
 136 #![feature(mips_target_feature)]
 137 #![feature(aarch64_target_feature)]
 138 #![feature(wasm_target_feature)]
 139 #![feature(avx512_target_feature)]
 140 #![feature(cmpxchg16b_target_feature)]
 141 #![feature(rtm_target_feature)]
 142 #![feature(f16c_target_feature)]
 143 #![feature(hexagon_target_feature)]
 144 #![feature(const_fn_transmute)]
 145 #![feature(abi_unadjusted)]
 146 #![feature(adx_target_feature)]
 147 #![feature(maybe_uninit_slice)]
 148 #![feature(maybe_uninit_extra)]
 149 #![feature(external_doc)]
 150 #![feature(associated_type_bounds)]
 151 #![feature(const_caller_location)]
 152 #![feature(slice_ptr_get)]
 153 #![feature(no_niche)] // rust-lang/rust#68303
 154 #![feature(unsafe_block_in_unsafe_fn)]
 155 #![deny(unsafe_op_in_unsafe_fn)]
 156
 157 #[prelude_import]
 158 #[allow(unused)]
 159 use prelude::v1::*;
 160
 161 #[cfg(not(test))] // See #65860
 162 #[macro_use]
 163 mod macros;
 164
 165 #[macro_use]
 166 mod internal_macros;
 167
 168 #[path = "num/int_macros.rs"]
 169 #[macro_use]
 170 mod int_macros;
 171
 172 #[path = "num/i128.rs"]
 173 pub mod i128;
 174 #[path = "num/i16.rs"]
 175 pub mod i16;
 176 #[path = "num/i32.rs"]
 177 pub mod i32;
 178 #[path = "num/i64.rs"]
 179 pub mod i64;
 180 #[path = "num/i8.rs"]
 181 pub mod i8;
 182 #[path = "num/isize.rs"]
 183 pub mod isize;
 184
 185 #[path = "num/u128.rs"]
 186 pub mod u128;
 187 #[path = "num/u16.rs"]
 188 pub mod u16;
 189 #[path = "num/u32.rs"]
 190 pub mod u32;
 191 #[path = "num/u64.rs"]
 192 pub mod u64;
 193 #[path = "num/u8.rs"]
 194 pub mod u8;
 195 #[path = "num/usize.rs"]
 196 pub mod usize;
 197
 198 #[path = "num/f32.rs"]
 199 pub mod f32;
 200 #[path = "num/f64.rs"]
 201 pub mod f64;
 202
 203 #[macro_use]
 204 pub mod num;
 205
 206 /* The libcore prelude, not as all-encompassing as the libstd prelude */
 207
 208 pub mod prelude;
 209
 210 /* Core modules for ownership management */
 211
 212 pub mod hint;
 213 pub mod intrinsics;
 214 pub mod mem;
 215 pub mod ptr;
 216
 217 /* Core language traits */
 218
 219 pub mod borrow;
 220 #[cfg(not(test))] // See #65860
 221 pub mod clone;
 222 #[cfg(not(test))] // See #65860
 223 pub mod cmp;
 224 pub mod convert;
 225 #[cfg(not(test))] // See #65860
 226 pub mod default;
 227 #[cfg(not(test))] // See #65860
 228 pub mod marker;
 229 pub mod ops;
 230
 231 /* Core types and methods on primitives */
 232
 233 pub mod any;
 234 #[cfg(not(test))] // See #65860
 235 pub mod array;
 236 pub mod ascii;
 237 pub mod cell;
 238 pub mod char;
 239 pub mod ffi;
 240 #[cfg(not(test))] // See #65860
 241 pub mod iter;
 242 #[unstable(feature = "once_cell", issue = "74465")]
 243 pub mod lazy;
 244 pub mod option;
 245 pub mod panic;
 246 pub mod panicking;
 247 #[cfg(not(test))] // See #65860
 248 pub mod pin;
 249 pub mod raw;
 250 pub mod result;
 251 pub mod sync;
 252
 253 #[cfg(not(test))] // See #65860
 254 pub mod fmt;
 255 #[cfg(not(test))] // See #65860
 256 pub mod hash;
 257 pub mod slice;
 258 #[cfg(not(test))] // See #65860
 259 pub mod str;
 260 pub mod time;
 261
 262 pub mod unicode;
 263
 264 /* Async */
 265 #[cfg(not(test))] // See #65860
 266 pub mod future;
 267 pub mod task;
 268
 269 /* Heap memory allocator trait */
 270 #[allow(missing_docs)]
 271 pub mod alloc;
 272
 273 // note: does not need to be public
 274 mod bool;
 275 mod tuple;
 276 mod unit;
 277
 278 #[stable(feature = "core_primitive", since = "1.43.0")]
 279 pub mod primitive;
 280
 281 // Pull in the `core_arch` crate directly into libcore. The contents of
 282 // `core_arch` are in a different repository: rust-lang/stdarch.
 283 //
 284 // `core_arch` depends on libcore, but the contents of this module are
 285 // set up in such a way that directly pulling it here works such that the
 286 // crate uses the this crate as its libcore.
 287 #[path = "../../stdarch/crates/core_arch/src/mod.rs"]
 288 #[allow(
 289     missing_docs,
 290     missing_debug_implementations,
 291     dead_code,
 292     unused_imports,
 293     unsafe_op_in_unsafe_fn
 294 )]
 295 // FIXME: This annotation should be moved into rust-lang/stdarch after clashing_extern_declarations is
 296 // merged. It currently cannot because bootstrap fails as the lint hasn't been defined yet.
 297 #[allow(clashing_extern_declarations)]
 298 #[unstable(feature = "stdsimd", issue = "48556")]
 299 mod core_arch;
 300
 301 #[stable(feature = "simd_arch", since = "1.27.0")]
 302 pub use core_arch::arch;