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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 {}
43
44 // Note that the symbols here are prefixed by default on OSX (we don't
45 // explicitly request it), and on Android and DragonFly we explicitly request
46 // it as unprefixing cause segfaults (mismatches in allocators).
47 extern {
48 #[cfg_attr(any(target_os = "macos", target_os = "android", target_os = "ios",
49 target_os = "dragonfly"),
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"),
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"),
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"),
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"),
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 const MIN_ALIGN: usize = 16;
82
83 // MALLOCX_ALIGN(a) macro
84 fn mallocx_align(a: usize) -> c_int {
85 a.trailing_zeros() as c_int
86 }
87
88 fn align_to_flags(align: usize) -> c_int {
89 if align <= MIN_ALIGN {
90 0
91 } else {
92 mallocx_align(align)
93 }
94 }
95
96 #[no_mangle]
97 pub extern "C" fn __rust_allocate(size: usize, align: usize) -> *mut u8 {
98 let flags = align_to_flags(align);
99 unsafe { mallocx(size as size_t, flags) as *mut u8 }
100 }
101
102 #[no_mangle]
103 pub extern "C" fn __rust_reallocate(ptr: *mut u8,
104 _old_size: usize,
105 size: usize,
106 align: usize)
107 -> *mut u8 {
108 let flags = align_to_flags(align);
109 unsafe { rallocx(ptr as *mut c_void, size as size_t, flags) as *mut u8 }
110 }
111
112 #[no_mangle]
113 pub extern "C" fn __rust_reallocate_inplace(ptr: *mut u8,
114 _old_size: usize,
115 size: usize,
116 align: usize)
117 -> usize {
118 let flags = align_to_flags(align);
119 unsafe { xallocx(ptr as *mut c_void, size as size_t, 0, flags) as usize }
120 }
121
122 #[no_mangle]
123 pub extern "C" fn __rust_deallocate(ptr: *mut u8, old_size: usize, align: usize) {
124 let flags = align_to_flags(align);
125 unsafe { sdallocx(ptr as *mut c_void, old_size as size_t, flags) }
126 }
127
128 #[no_mangle]
129 pub extern "C" fn __rust_usable_size(size: usize, align: usize) -> usize {
130 let flags = align_to_flags(align);
131 unsafe { nallocx(size as size_t, flags) as usize }
132 }
133
134 // These symbols are used by jemalloc on android but the really old android
135 // we're building on doesn't have them defined, so just make sure the symbols
136 // are available.
137 #[no_mangle]
138 #[cfg(target_os = "android")]
139 pub extern fn pthread_atfork(_prefork: *mut u8,
140 _postfork_parent: *mut u8,
141 _postfork_child: *mut u8) -> i32 {
142 0
143 }