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6d03d481 ST |
1 | // gc.cc -- garbage collection of unused sections |
2 | ||
3 | // Copyright 2009 Free Software Foundation, Inc. | |
4 | // Written by Sriraman Tallam <tmsriram@google.com>. | |
5 | ||
6 | // This file is part of gold. | |
7 | ||
8 | // This program is free software; you can redistribute it and/or modify | |
9 | // it under the terms of the GNU General Public License as published by | |
10 | // the Free Software Foundation; either version 3 of the License, or | |
11 | // (at your option) any later version. | |
12 | ||
13 | // This program is distributed in the hope that it will be useful, | |
14 | // but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | // GNU General Public License for more details. | |
17 | ||
18 | // You should have received a copy of the GNU General Public License | |
19 | // along with this program; if not, write to the Free Software | |
20 | // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, | |
21 | // MA 02110-1301, USA. | |
22 | ||
23 | ||
24 | #include "gold.h" | |
25 | #include "object.h" | |
26 | #include "gc.h" | |
27 | #include "symtab.h" | |
28 | ||
29 | namespace gold | |
30 | { | |
31 | ||
32 | // Garbage collection uses a worklist style algorithm to determine the | |
33 | // transitive closure of all referenced sections. | |
34 | void | |
35 | Garbage_collection::do_transitive_closure() | |
36 | { | |
37 | while (!this->worklist().empty()) | |
38 | { | |
39 | // Add elements from the work list to the referenced list | |
40 | // one by one. | |
41 | Section_id entry = this->worklist().front(); | |
42 | this->worklist().pop(); | |
43 | if (this->referenced_list().find(entry) | |
44 | == this->referenced_list().end()) | |
45 | { | |
46 | this->referenced_list().insert(entry); | |
47 | } | |
48 | else | |
49 | { | |
50 | continue; | |
51 | } | |
52 | Garbage_collection::Section_ref::iterator find_it = | |
53 | this->section_reloc_map().find(entry); | |
54 | if (find_it == this->section_reloc_map().end()) | |
55 | continue; | |
56 | Garbage_collection::Sections_reachable v = find_it->second; | |
57 | // Scan the vector of references for each work_list entry. | |
58 | for (Garbage_collection::Sections_reachable::iterator it_v = v.begin(); | |
59 | it_v != v.end(); | |
60 | ++it_v) | |
61 | { | |
62 | // Do not add already processed sections to the work_list. | |
63 | if (this->referenced_list().find(*it_v) | |
64 | == this->referenced_list().end()) | |
65 | { | |
66 | this->worklist().push(*it_v); | |
67 | } | |
68 | } | |
69 | } | |
70 | this->worklist_ready(); | |
71 | } | |
72 | ||
73 | } // End namespace gold. | |
74 |