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ead1e424 ILT |
1 | // common.cc -- handle common symbols for gold |
2 | ||
ebdbb458 | 3 | // Copyright 2006, 2007, 2008 Free Software Foundation, Inc. |
6cb15b7f ILT |
4 | // Written by Ian Lance Taylor <iant@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 | ||
ead1e424 ILT |
23 | #include "gold.h" |
24 | ||
25 | #include <algorithm> | |
26 | ||
27 | #include "workqueue.h" | |
28 | #include "layout.h" | |
29 | #include "output.h" | |
f6ce93d6 | 30 | #include "symtab.h" |
ead1e424 ILT |
31 | #include "common.h" |
32 | ||
33 | namespace gold | |
34 | { | |
35 | ||
36 | // Allocate_commons_task methods. | |
37 | ||
38 | // This task allocates the common symbols. We need a lock on the | |
39 | // symbol table. | |
40 | ||
17a1d0a9 ILT |
41 | Task_token* |
42 | Allocate_commons_task::is_runnable() | |
ead1e424 ILT |
43 | { |
44 | if (!this->symtab_lock_->is_writable()) | |
17a1d0a9 ILT |
45 | return this->symtab_lock_; |
46 | return NULL; | |
ead1e424 ILT |
47 | } |
48 | ||
49 | // Return the locks we hold: one on the symbol table, and one blocker. | |
50 | ||
17a1d0a9 ILT |
51 | void |
52 | Allocate_commons_task::locks(Task_locker* tl) | |
ead1e424 | 53 | { |
17a1d0a9 ILT |
54 | tl->add(this, this->blocker_); |
55 | tl->add(this, this->symtab_lock_); | |
ead1e424 ILT |
56 | } |
57 | ||
58 | // Allocate the common symbols. | |
59 | ||
60 | void | |
61 | Allocate_commons_task::run(Workqueue*) | |
62 | { | |
155a0dd7 | 63 | this->symtab_->allocate_commons(this->layout_); |
ead1e424 ILT |
64 | } |
65 | ||
66 | // This class is used to sort the common symbol by size. We put the | |
67 | // larger common symbols first. | |
68 | ||
69 | template<int size> | |
70 | class Sort_commons | |
71 | { | |
72 | public: | |
73 | Sort_commons(const Symbol_table* symtab) | |
74 | : symtab_(symtab) | |
75 | { } | |
76 | ||
77 | bool operator()(const Symbol* a, const Symbol* b) const; | |
78 | ||
79 | private: | |
80 | const Symbol_table* symtab_; | |
81 | }; | |
82 | ||
83 | template<int size> | |
84 | bool | |
85 | Sort_commons<size>::operator()(const Symbol* pa, const Symbol* pb) const | |
86 | { | |
87 | if (pa == NULL) | |
88 | return false; | |
89 | if (pb == NULL) | |
90 | return true; | |
91 | ||
92 | const Symbol_table* symtab = this->symtab_; | |
7d1a9ebb ILT |
93 | const Sized_symbol<size>* psa = symtab->get_sized_symbol<size>(pa); |
94 | const Sized_symbol<size>* psb = symtab->get_sized_symbol<size>(pb); | |
ead1e424 | 95 | |
49bdd526 | 96 | // Sort by largest size first. |
ead1e424 ILT |
97 | typename Sized_symbol<size>::Size_type sa = psa->symsize(); |
98 | typename Sized_symbol<size>::Size_type sb = psb->symsize(); | |
99 | if (sa < sb) | |
100 | return false; | |
49bdd526 | 101 | else if (sb < sa) |
ead1e424 ILT |
102 | return true; |
103 | ||
49bdd526 ILT |
104 | // When the symbols are the same size, we sort them by alignment, |
105 | // largest alignment first. | |
ead1e424 ILT |
106 | typename Sized_symbol<size>::Value_type va = psa->value(); |
107 | typename Sized_symbol<size>::Value_type vb = psb->value(); | |
108 | if (va < vb) | |
109 | return false; | |
49bdd526 | 110 | else if (vb < va) |
ead1e424 ILT |
111 | return true; |
112 | ||
113 | // Otherwise we stabilize the sort by sorting by name. | |
114 | return strcmp(psa->name(), psb->name()) < 0; | |
115 | } | |
116 | ||
117 | // Allocate the common symbols. | |
118 | ||
119 | void | |
155a0dd7 | 120 | Symbol_table::allocate_commons(Layout* layout) |
ead1e424 | 121 | { |
8851ecca | 122 | if (parameters->target().get_size() == 32) |
8ae3da90 ILT |
123 | { |
124 | #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG) | |
155a0dd7 | 125 | this->do_allocate_commons<32>(layout); |
8ae3da90 ILT |
126 | #else |
127 | gold_unreachable(); | |
128 | #endif | |
129 | } | |
8851ecca | 130 | else if (parameters->target().get_size() == 64) |
8ae3da90 ILT |
131 | { |
132 | #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG) | |
155a0dd7 | 133 | this->do_allocate_commons<64>(layout); |
8ae3da90 ILT |
134 | #else |
135 | gold_unreachable(); | |
136 | #endif | |
137 | } | |
ead1e424 | 138 | else |
a3ad94ed | 139 | gold_unreachable(); |
ead1e424 ILT |
140 | } |
141 | ||
142 | // Allocated the common symbols, sized version. | |
143 | ||
144 | template<int size> | |
145 | void | |
155a0dd7 ILT |
146 | Symbol_table::do_allocate_commons(Layout* layout) |
147 | { | |
148 | this->do_allocate_commons_list<size>(layout, false, &this->commons_); | |
149 | this->do_allocate_commons_list<size>(layout, true, &this->tls_commons_); | |
150 | } | |
151 | ||
152 | // Allocate the common symbols in a list. IS_TLS indicates whether | |
153 | // these are TLS common symbols. | |
154 | ||
155 | template<int size> | |
156 | void | |
157 | Symbol_table::do_allocate_commons_list(Layout* layout, bool is_tls, | |
158 | Commons_type* commons) | |
ead1e424 ILT |
159 | { |
160 | typedef typename Sized_symbol<size>::Value_type Value_type; | |
161 | typedef typename Sized_symbol<size>::Size_type Size_type; | |
162 | ||
163 | // We've kept a list of all the common symbols. But the symbol may | |
164 | // have been resolved to a defined symbol by now. And it may be a | |
165 | // forwarder. First remove all non-common symbols. | |
166 | bool any = false; | |
167 | uint64_t addralign = 0; | |
155a0dd7 ILT |
168 | for (Commons_type::iterator p = commons->begin(); |
169 | p != commons->end(); | |
ead1e424 ILT |
170 | ++p) |
171 | { | |
172 | Symbol* sym = *p; | |
173 | if (sym->is_forwarder()) | |
174 | { | |
175 | sym = this->resolve_forwards(sym); | |
176 | *p = sym; | |
177 | } | |
178 | if (!sym->is_common()) | |
179 | *p = NULL; | |
180 | else | |
181 | { | |
182 | any = true; | |
7d1a9ebb | 183 | Sized_symbol<size>* ssym = this->get_sized_symbol<size>(sym); |
ead1e424 ILT |
184 | if (ssym->value() > addralign) |
185 | addralign = ssym->value(); | |
186 | } | |
187 | } | |
188 | if (!any) | |
189 | return; | |
190 | ||
191 | // Sort the common symbols by size, so that they pack better into | |
192 | // memory. | |
155a0dd7 | 193 | std::sort(commons->begin(), commons->end(), |
ead1e424 ILT |
194 | Sort_commons<size>(this)); |
195 | ||
155a0dd7 | 196 | // Place them in a newly allocated BSS section. |
ead1e424 | 197 | |
a3ad94ed | 198 | Output_data_space *poc = new Output_data_space(addralign); |
ead1e424 | 199 | |
155a0dd7 ILT |
200 | const char* name = ".bss"; |
201 | elfcpp::Elf_Xword flags = elfcpp::SHF_WRITE | elfcpp::SHF_ALLOC; | |
202 | if (is_tls) | |
203 | { | |
204 | name = ".tbss"; | |
205 | flags |= elfcpp::SHF_TLS; | |
206 | } | |
207 | layout->add_output_section_data(name, elfcpp::SHT_NOBITS, flags, poc); | |
ead1e424 ILT |
208 | |
209 | // Allocate them all. | |
210 | ||
211 | off_t off = 0; | |
155a0dd7 ILT |
212 | for (Commons_type::iterator p = commons->begin(); |
213 | p != commons->end(); | |
ead1e424 ILT |
214 | ++p) |
215 | { | |
216 | Symbol* sym = *p; | |
217 | if (sym == NULL) | |
218 | break; | |
7d1a9ebb | 219 | Sized_symbol<size>* ssym = this->get_sized_symbol<size>(sym); |
ead1e424 | 220 | off = align_address(off, ssym->value()); |
c7912668 | 221 | ssym->allocate_common(poc, off); |
c7912668 | 222 | off += ssym->symsize(); |
ead1e424 ILT |
223 | } |
224 | ||
27bc2bce | 225 | poc->set_current_data_size(off); |
ead1e424 | 226 | |
155a0dd7 | 227 | commons->clear(); |
ead1e424 ILT |
228 | } |
229 | ||
230 | } // End namespace gold. |