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
|
// 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;
use unstable::intrinsics::TyDesc;
use unstable::raw;
type DropGlue<'a> = 'a |**TyDesc, *c_void|;
static RC_IMMORTAL : uint = 0x77777777;
/*
* Box annihilation
*
* This runs at task death to free all boxes.
*/
struct AnnihilateStats {
n_total_boxes: uint,
n_bytes_freed: uint
}
unsafe fn each_live_alloc(read_next_before: bool,
f: |alloc: *mut raw::Box<()>| -> bool)
-> bool {
//! Walks the internal list of allocations
use rt::local_heap;
let mut alloc = local_heap::live_allocs();
while alloc != ptr::mut_null() {
let next_before = (*alloc).next;
if !f(alloc) {
return false;
}
if read_next_before {
alloc = next_before;
} else {
alloc = (*alloc).next;
}
}
return true;
}
#[cfg(unix)]
fn debug_mem() -> bool {
// XXX: Need to port the environment struct to newsched
false
}
#[cfg(windows)]
fn debug_mem() -> bool {
false
}
/// Destroys all managed memory (i.e. @ boxes) held by the current task.
pub unsafe fn annihilate() {
use rt::local_heap::local_free;
use mem;
let mut stats = AnnihilateStats {
n_total_boxes: 0,
n_bytes_freed: 0
};
// 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.
each_live_alloc(true, |alloc| {
stats.n_total_boxes += 1;
(*alloc).ref_count = RC_IMMORTAL;
true
});
// 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.
each_live_alloc(false, |alloc| {
let tydesc = (*alloc).type_desc;
let data = &(*alloc).data as *();
((*tydesc).drop_glue)(data as *i8);
true
});
// 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.
each_live_alloc(true, |alloc| {
stats.n_bytes_freed +=
(*((*alloc).type_desc)).size
+ mem::size_of::<raw::Box<()>>();
local_free(alloc as *i8);
true
});
if debug_mem() {
// We do logging here w/o allocation.
debug!("annihilator stats:\n \
total boxes: {}\n \
bytes freed: {}",
stats.n_total_boxes, stats.n_bytes_freed);
}
}
|
