src/liballoc_jemalloc/lib.rs

   1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 #![crate_name = "alloc_jemalloc"]
  12 #![crate_type = "rlib"]
  13 #![no_std]
  14 #![allocator]
  15 #![unstable(feature = "alloc_jemalloc",
  16             reason = "this library is unlikely to be stabilized in its current \
  17                       form or name",
  18             issue = "27783")]
  19 #![cfg_attr(not(stage0), deny(warnings))]
  20 #![feature(allocator)]
  21 #![feature(libc)]
  22 #![feature(staged_api)]
  23
  24 extern crate libc;
  25
  26 use libc::{c_int, c_void, size_t};
  27
  28 // Linkage directives to pull in jemalloc and its dependencies.
  29 //
  30 // On some platforms we need to be sure to link in `pthread` which jemalloc
  31 // depends on, and specifically on android we need to also link to libgcc.
  32 // Currently jemalloc is compiled with gcc which will generate calls to
  33 // intrinsics that are libgcc specific (e.g. those intrinsics aren't present in
  34 // libcompiler-rt), so link that in to get that support.
  35 #[link(name = "jemalloc", kind = "static")]
  36 #[cfg_attr(target_os = "android", link(name = "gcc"))]
  37 #[cfg_attr(all(not(windows),
  38                not(target_os = "android"),
  39                not(target_env = "musl")),
  40            link(name = "pthread"))]
  41 #[cfg(not(cargobuild))]
  42 extern "C" {}
  43
  44 // Note that the symbols here are prefixed by default on OSX and Windows (we
  45 // don't explicitly request it), and on Android and DragonFly we explicitly
  46 // request it as unprefixing cause segfaults (mismatches in allocators).
  47 extern "C" {
  48     #[cfg_attr(any(target_os = "macos", target_os = "android", target_os = "ios",
  49                    target_os = "dragonfly", target_os = "windows"),
  50                link_name = "je_mallocx")]
  51     fn mallocx(size: size_t, flags: c_int) -> *mut c_void;
  52     #[cfg_attr(any(target_os = "macos", target_os = "android", target_os = "ios",
  53                    target_os = "dragonfly", target_os = "windows"),
  54                link_name = "je_rallocx")]
  55     fn rallocx(ptr: *mut c_void, size: size_t, flags: c_int) -> *mut c_void;
  56     #[cfg_attr(any(target_os = "macos", target_os = "android", target_os = "ios",
  57                    target_os = "dragonfly", target_os = "windows"),
  58                link_name = "je_xallocx")]
  59     fn xallocx(ptr: *mut c_void, size: size_t, extra: size_t, flags: c_int) -> size_t;
  60     #[cfg_attr(any(target_os = "macos", target_os = "android", target_os = "ios",
  61                    target_os = "dragonfly", target_os = "windows"),
  62                link_name = "je_sdallocx")]
  63     fn sdallocx(ptr: *mut c_void, size: size_t, flags: c_int);
  64     #[cfg_attr(any(target_os = "macos", target_os = "android", target_os = "ios",
  65                    target_os = "dragonfly", target_os = "windows"),
  66                link_name = "je_nallocx")]
  67     fn nallocx(size: size_t, flags: c_int) -> size_t;
  68 }
  69
  70 // The minimum alignment guaranteed by the architecture. This value is used to
  71 // add fast paths for low alignment values. In practice, the alignment is a
  72 // constant at the call site and the branch will be optimized out.
  73 #[cfg(all(any(target_arch = "arm",
  74               target_arch = "mips",
  75               target_arch = "powerpc")))]
  76 const MIN_ALIGN: usize = 8;
  77 #[cfg(all(any(target_arch = "x86",
  78               target_arch = "x86_64",
  79               target_arch = "aarch64",
  80               target_arch = "powerpc64",
  81               target_arch = "mips64",
  82               target_arch = "s390x")))]
  83 const MIN_ALIGN: usize = 16;
  84
  85 // MALLOCX_ALIGN(a) macro
  86 fn mallocx_align(a: usize) -> c_int {
  87     a.trailing_zeros() as c_int
  88 }
  89
  90 fn align_to_flags(align: usize) -> c_int {
  91     if align <= MIN_ALIGN {
  92         0
  93     } else {
  94         mallocx_align(align)
  95     }
  96 }
  97
  98 #[no_mangle]
  99 pub extern "C" fn __rust_allocate(size: usize, align: usize) -> *mut u8 {
 100     let flags = align_to_flags(align);
 101     unsafe { mallocx(size as size_t, flags) as *mut u8 }
 102 }
 103
 104 #[no_mangle]
 105 pub extern "C" fn __rust_reallocate(ptr: *mut u8,
 106                                     _old_size: usize,
 107                                     size: usize,
 108                                     align: usize)
 109                                     -> *mut u8 {
 110     let flags = align_to_flags(align);
 111     unsafe { rallocx(ptr as *mut c_void, size as size_t, flags) as *mut u8 }
 112 }
 113
 114 #[no_mangle]
 115 pub extern "C" fn __rust_reallocate_inplace(ptr: *mut u8,
 116                                             _old_size: usize,
 117                                             size: usize,
 118                                             align: usize)
 119                                             -> usize {
 120     let flags = align_to_flags(align);
 121     unsafe { xallocx(ptr as *mut c_void, size as size_t, 0, flags) as usize }
 122 }
 123
 124 #[no_mangle]
 125 pub extern "C" fn __rust_deallocate(ptr: *mut u8, old_size: usize, align: usize) {
 126     let flags = align_to_flags(align);
 127     unsafe { sdallocx(ptr as *mut c_void, old_size as size_t, flags) }
 128 }
 129
 130 #[no_mangle]
 131 pub extern "C" fn __rust_usable_size(size: usize, align: usize) -> usize {
 132     let flags = align_to_flags(align);
 133     unsafe { nallocx(size as size_t, flags) as usize }
 134 }
 135
 136 // These symbols are used by jemalloc on android but the really old android
 137 // we're building on doesn't have them defined, so just make sure the symbols
 138 // are available.
 139 #[no_mangle]
 140 #[cfg(target_os = "android")]
 141 pub extern "C" fn pthread_atfork(_prefork: *mut u8,
 142                                  _postfork_parent: *mut u8,
 143                                  _postfork_child: *mut u8)
 144                                  -> i32 {
 145     0
 146 }