1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
|
// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#[doc(hidden)];
use libc::c_void;
use ptr::{mut_null};
use repr::BoxRepr;
use cast::transmute;
use unstable::intrinsics::TyDesc;
type DropGlue<'self> = &'self fn(**TyDesc, *c_void);
/*
* Box annihilation
*
* This runs at task death to free all boxes.
*/
struct AnnihilateStats {
n_total_boxes: uint,
n_unique_boxes: uint,
n_bytes_freed: uint
}
unsafe fn each_live_alloc(read_next_before: bool,
f: &fn(box: *mut BoxRepr, uniq: bool) -> bool) -> bool {
//! Walks the internal list of allocations
use managed;
use rt::local_heap;
let box = local_heap::live_allocs();
let mut box: *mut BoxRepr = transmute(copy box);
while box != mut_null() {
let next_before = transmute(copy (*box).header.next);
let uniq =
(*box).header.ref_count == managed::raw::RC_MANAGED_UNIQUE;
if !f(box, uniq) {
return false;
}
if read_next_before {
box = next_before;
} else {
box = transmute(copy (*box).header.next);
}
}
return true;
}
#[cfg(unix)]
fn debug_mem() -> bool {
use rt;
use rt::OldTaskContext;
// XXX: Need to port the environment struct to newsched
match rt::context() {
OldTaskContext => ::rt::env::get().debug_mem,
_ => false
}
}
#[cfg(windows)]
fn debug_mem() -> bool {
false
}
#[inline]
#[cfg(not(stage0))]
unsafe fn call_drop_glue(tydesc: *TyDesc, data: *i8) {
// This function should be inlined when stage0 is gone
((*tydesc).drop_glue)(data);
}
#[inline]
#[cfg(stage0)]
unsafe fn call_drop_glue(tydesc: *TyDesc, data: *i8) {
((*tydesc).drop_glue)(0 as **TyDesc, data);
}
/// Destroys all managed memory (i.e. @ boxes) held by the current task.
pub unsafe fn annihilate() {
use rt::local_heap::local_free;
use io::WriterUtil;
use io;
use libc;
use rt::borrowck;
use sys;
use managed;
let mut stats = AnnihilateStats {
n_total_boxes: 0,
n_unique_boxes: 0,
n_bytes_freed: 0
};
// Quick hack: we need to free this list upon task exit, and this
// is a convenient place to do it.
borrowck::clear_task_borrow_list();
// Pass 1: Make all boxes immortal.
//
// In this pass, nothing gets freed, so it does not matter whether
// we read the next field before or after the callback.
for each_live_alloc(true) |box, uniq| {
stats.n_total_boxes += 1;
if uniq {
stats.n_unique_boxes += 1;
} else {
(*box).header.ref_count = managed::raw::RC_IMMORTAL;
}
}
// Pass 2: Drop all boxes.
//
// In this pass, unique-managed boxes may get freed, but not
// managed boxes, so we must read the `next` field *after* the
// callback, as the original value may have been freed.
for each_live_alloc(false) |box, uniq| {
if !uniq {
let tydesc: *TyDesc = transmute(copy (*box).header.type_desc);
let data = transmute(&(*box).data);
call_drop_glue(tydesc, data);
}
}
// Pass 3: Free all boxes.
//
// In this pass, managed boxes may get freed (but not
// unique-managed boxes, though I think that none of those are
// left), so we must read the `next` field before, since it will
// not be valid after.
for each_live_alloc(true) |box, uniq| {
if !uniq {
stats.n_bytes_freed +=
(*((*box).header.type_desc)).size
+ sys::size_of::<BoxRepr>();
local_free(transmute(box));
}
}
if debug_mem() {
// We do logging here w/o allocation.
let dbg = libc::STDERR_FILENO as io::fd_t;
dbg.write_str("annihilator stats:");
dbg.write_str("\n total_boxes: ");
dbg.write_uint(stats.n_total_boxes);
dbg.write_str("\n unique_boxes: ");
dbg.write_uint(stats.n_unique_boxes);
dbg.write_str("\n bytes_freed: ");
dbg.write_uint(stats.n_bytes_freed);
dbg.write_str("\n");
}
}
/// Bindings to the runtime
pub mod rustrt {
use libc::c_void;
#[link_name = "rustrt"]
pub extern {
#[rust_stack]
// FIXME (#4386): Unable to make following method private.
pub unsafe fn rust_get_task() -> *c_void;
}
}
|
