diff options
| -rw-r--r-- | build_sysroot/alloc_system/Cargo.toml | 2 | ||||
| -rw-r--r-- | build_sysroot/alloc_system/lib.rs | 134 |
2 files changed, 4 insertions, 132 deletions
diff --git a/build_sysroot/alloc_system/Cargo.toml b/build_sysroot/alloc_system/Cargo.toml index 9fffca84300..09b13db7726 100644 --- a/build_sysroot/alloc_system/Cargo.toml +++ b/build_sysroot/alloc_system/Cargo.toml @@ -2,11 +2,13 @@ authors = ["The Rust Project Developers", "bjorn3 (edited to be usable outside the rust source)"] name = "alloc_system" version = "0.0.0" + [lib] name = "alloc_system" path = "lib.rs" test = false doc = false + [dependencies] core = { path = "../sysroot_src/library/core" } libc = { version = "0.2.43", features = ['rustc-dep-of-std'], default-features = false } diff --git a/build_sysroot/alloc_system/lib.rs b/build_sysroot/alloc_system/lib.rs index c832d5e5ebb..405ccbae6d6 100644 --- a/build_sysroot/alloc_system/lib.rs +++ b/build_sysroot/alloc_system/lib.rs @@ -8,66 +8,24 @@ // option. This file may not be copied, modified, or distributed // except according to those terms. #![no_std] -#![allow(unused_attributes)] -#![unstable(feature = "alloc_system", - reason = "this library is unlikely to be stabilized in its current \ - form or name", - issue = "32838")] #![feature(allocator_api)] -#![feature(core_intrinsics)] -#![feature(nll)] -#![feature(staged_api)] -#![feature(rustc_attrs)] -#![feature(alloc_layout_extra)] -#![cfg_attr( - all(target_arch = "wasm32", not(target_os = "emscripten")), - feature(integer_atomics, stdsimd) -)] #![cfg_attr(any(unix, target_os = "redox"), feature(libc))] + // The minimum alignment guaranteed by the architecture. This value is used to // add fast paths for low alignment values. #[cfg(all(any(target_arch = "x86", target_arch = "arm", target_arch = "mips", target_arch = "powerpc", - target_arch = "powerpc64", - target_arch = "asmjs", - target_arch = "wasm32")))] -#[allow(dead_code)] + target_arch = "powerpc64")))] const MIN_ALIGN: usize = 8; #[cfg(all(any(target_arch = "x86_64", target_arch = "aarch64", target_arch = "mips64", target_arch = "s390x", target_arch = "sparc64")))] -#[allow(dead_code)] const MIN_ALIGN: usize = 16; -/// The default memory allocator provided by the operating system. -/// -/// This is based on `malloc` on Unix platforms and `HeapAlloc` on Windows, -/// plus related functions. -/// -/// This type can be used in a `static` item -/// with the `#[global_allocator]` attribute -/// to force the global allocator to be the system’s one. -/// (The default is jemalloc for executables, on some platforms.) -/// -/// ```rust -/// use std::alloc::System; -/// -/// #[global_allocator] -/// static A: System = System; -/// -/// fn main() { -/// let a = Box::new(4); // Allocates from the system allocator. -/// println!("{}", a); -/// } -/// ``` -/// -/// It can also be used directly to allocate memory -/// independently of the standard library’s global allocator. -#[stable(feature = "alloc_system_type", since = "1.28.0")] pub struct System; #[cfg(any(windows, unix, target_os = "redox"))] mod realloc_fallback { @@ -96,7 +54,6 @@ mod platform { use MIN_ALIGN; use System; use core::alloc::{GlobalAlloc, Layout}; - #[stable(feature = "alloc_system_type", since = "1.28.0")] unsafe impl GlobalAlloc for System { #[inline] unsafe fn alloc(&self, layout: Layout) -> *mut u8 { @@ -221,7 +178,6 @@ mod platform { }; ptr as *mut u8 } - #[stable(feature = "alloc_system_type", since = "1.28.0")] unsafe impl GlobalAlloc for System { #[inline] unsafe fn alloc(&self, layout: Layout) -> *mut u8 { @@ -254,89 +210,3 @@ mod platform { } } } -// This is an implementation of a global allocator on the wasm32 platform when -// emscripten is not in use. In that situation there's no actual runtime for us -// to lean on for allocation, so instead we provide our own! -// -// The wasm32 instruction set has two instructions for getting the current -// amount of memory and growing the amount of memory. These instructions are the -// foundation on which we're able to build an allocator, so we do so! Note that -// the instructions are also pretty "global" and this is the "global" allocator -// after all! -// -// The current allocator here is the `dlmalloc` crate which we've got included -// in the rust-lang/rust repository as a submodule. The crate is a port of -// dlmalloc.c from C to Rust and is basically just so we can have "pure Rust" -// for now which is currently technically required (can't link with C yet). -// -// The crate itself provides a global allocator which on wasm has no -// synchronization as there are no threads! -#[cfg(all(target_arch = "wasm32", not(target_os = "emscripten")))] -mod platform { - extern crate dlmalloc; - use core::alloc::{GlobalAlloc, Layout}; - use System; - static mut DLMALLOC: dlmalloc::Dlmalloc = dlmalloc::DLMALLOC_INIT; - #[stable(feature = "alloc_system_type", since = "1.28.0")] - unsafe impl GlobalAlloc for System { - #[inline] - unsafe fn alloc(&self, layout: Layout) -> *mut u8 { - let _lock = lock::lock(); - DLMALLOC.malloc(layout.size(), layout.align()) - } - #[inline] - unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 { - let _lock = lock::lock(); - DLMALLOC.calloc(layout.size(), layout.align()) - } - #[inline] - unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) { - let _lock = lock::lock(); - DLMALLOC.free(ptr, layout.size(), layout.align()) - } - #[inline] - unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 { - let _lock = lock::lock(); - DLMALLOC.realloc(ptr, layout.size(), layout.align(), new_size) - } - } - #[cfg(target_feature = "atomics")] - mod lock { - use core::arch::wasm32; - use core::sync::atomic::{AtomicI32, Ordering::SeqCst}; - static LOCKED: AtomicI32 = AtomicI32::new(0); - pub struct DropLock; - pub fn lock() -> DropLock { - loop { - if LOCKED.swap(1, SeqCst) == 0 { - return DropLock - } - unsafe { - let r = wasm32::atomic::wait_i32( - &LOCKED as *const AtomicI32 as *mut i32, - 1, // expected value - -1, // timeout - ); - debug_assert!(r == 0 || r == 1); - } - } - } - impl Drop for DropLock { - fn drop(&mut self) { - let r = LOCKED.swap(0, SeqCst); - debug_assert_eq!(r, 1); - unsafe { - wasm32::atomic::wake( - &LOCKED as *const AtomicI32 as *mut i32, - 1, // only one thread - ); - } - } - } - } - #[cfg(not(target_feature = "atomics"))] - mod lock { - #[inline] - pub fn lock() {} // no atomics, no threads, that's easy! - } -} |