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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" | |
7d9e3d98 | 28 | #include "mapfile.h" |
ead1e424 ILT |
29 | #include "layout.h" |
30 | #include "output.h" | |
f6ce93d6 | 31 | #include "symtab.h" |
ead1e424 ILT |
32 | #include "common.h" |
33 | ||
34 | namespace gold | |
35 | { | |
36 | ||
37 | // Allocate_commons_task methods. | |
38 | ||
39 | // This task allocates the common symbols. We need a lock on the | |
40 | // symbol table. | |
41 | ||
17a1d0a9 ILT |
42 | Task_token* |
43 | Allocate_commons_task::is_runnable() | |
ead1e424 ILT |
44 | { |
45 | if (!this->symtab_lock_->is_writable()) | |
17a1d0a9 ILT |
46 | return this->symtab_lock_; |
47 | return NULL; | |
ead1e424 ILT |
48 | } |
49 | ||
50 | // Return the locks we hold: one on the symbol table, and one blocker. | |
51 | ||
17a1d0a9 ILT |
52 | void |
53 | Allocate_commons_task::locks(Task_locker* tl) | |
ead1e424 | 54 | { |
17a1d0a9 ILT |
55 | tl->add(this, this->blocker_); |
56 | tl->add(this, this->symtab_lock_); | |
ead1e424 ILT |
57 | } |
58 | ||
59 | // Allocate the common symbols. | |
60 | ||
61 | void | |
62 | Allocate_commons_task::run(Workqueue*) | |
63 | { | |
7d9e3d98 | 64 | this->symtab_->allocate_commons(this->layout_, this->mapfile_); |
ead1e424 ILT |
65 | } |
66 | ||
67 | // This class is used to sort the common symbol by size. We put the | |
68 | // larger common symbols first. | |
69 | ||
70 | template<int size> | |
71 | class Sort_commons | |
72 | { | |
73 | public: | |
74 | Sort_commons(const Symbol_table* symtab) | |
75 | : symtab_(symtab) | |
76 | { } | |
77 | ||
78 | bool operator()(const Symbol* a, const Symbol* b) const; | |
79 | ||
80 | private: | |
81 | const Symbol_table* symtab_; | |
82 | }; | |
83 | ||
84 | template<int size> | |
85 | bool | |
86 | Sort_commons<size>::operator()(const Symbol* pa, const Symbol* pb) const | |
87 | { | |
88 | if (pa == NULL) | |
89 | return false; | |
90 | if (pb == NULL) | |
91 | return true; | |
92 | ||
93 | const Symbol_table* symtab = this->symtab_; | |
7d1a9ebb ILT |
94 | const Sized_symbol<size>* psa = symtab->get_sized_symbol<size>(pa); |
95 | const Sized_symbol<size>* psb = symtab->get_sized_symbol<size>(pb); | |
ead1e424 | 96 | |
49bdd526 | 97 | // Sort by largest size first. |
ead1e424 ILT |
98 | typename Sized_symbol<size>::Size_type sa = psa->symsize(); |
99 | typename Sized_symbol<size>::Size_type sb = psb->symsize(); | |
100 | if (sa < sb) | |
101 | return false; | |
49bdd526 | 102 | else if (sb < sa) |
ead1e424 ILT |
103 | return true; |
104 | ||
49bdd526 ILT |
105 | // When the symbols are the same size, we sort them by alignment, |
106 | // largest alignment first. | |
ead1e424 ILT |
107 | typename Sized_symbol<size>::Value_type va = psa->value(); |
108 | typename Sized_symbol<size>::Value_type vb = psb->value(); | |
109 | if (va < vb) | |
110 | return false; | |
49bdd526 | 111 | else if (vb < va) |
ead1e424 ILT |
112 | return true; |
113 | ||
114 | // Otherwise we stabilize the sort by sorting by name. | |
115 | return strcmp(psa->name(), psb->name()) < 0; | |
116 | } | |
117 | ||
118 | // Allocate the common symbols. | |
119 | ||
120 | void | |
7d9e3d98 | 121 | Symbol_table::allocate_commons(Layout* layout, Mapfile* mapfile) |
ead1e424 | 122 | { |
8851ecca | 123 | if (parameters->target().get_size() == 32) |
8ae3da90 ILT |
124 | { |
125 | #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG) | |
7d9e3d98 | 126 | this->do_allocate_commons<32>(layout, mapfile); |
8ae3da90 ILT |
127 | #else |
128 | gold_unreachable(); | |
129 | #endif | |
130 | } | |
8851ecca | 131 | else if (parameters->target().get_size() == 64) |
8ae3da90 ILT |
132 | { |
133 | #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG) | |
7d9e3d98 | 134 | this->do_allocate_commons<64>(layout, mapfile); |
8ae3da90 ILT |
135 | #else |
136 | gold_unreachable(); | |
137 | #endif | |
138 | } | |
ead1e424 | 139 | else |
a3ad94ed | 140 | gold_unreachable(); |
ead1e424 ILT |
141 | } |
142 | ||
143 | // Allocated the common symbols, sized version. | |
144 | ||
145 | template<int size> | |
146 | void | |
7d9e3d98 | 147 | Symbol_table::do_allocate_commons(Layout* layout, Mapfile* mapfile) |
155a0dd7 | 148 | { |
7d9e3d98 ILT |
149 | this->do_allocate_commons_list<size>(layout, false, &this->commons_, |
150 | mapfile); | |
151 | this->do_allocate_commons_list<size>(layout, true, &this->tls_commons_, | |
152 | mapfile); | |
155a0dd7 ILT |
153 | } |
154 | ||
155 | // Allocate the common symbols in a list. IS_TLS indicates whether | |
156 | // these are TLS common symbols. | |
157 | ||
158 | template<int size> | |
159 | void | |
160 | Symbol_table::do_allocate_commons_list(Layout* layout, bool is_tls, | |
7d9e3d98 ILT |
161 | Commons_type* commons, |
162 | Mapfile* mapfile) | |
ead1e424 ILT |
163 | { |
164 | typedef typename Sized_symbol<size>::Value_type Value_type; | |
165 | typedef typename Sized_symbol<size>::Size_type Size_type; | |
166 | ||
167 | // We've kept a list of all the common symbols. But the symbol may | |
168 | // have been resolved to a defined symbol by now. And it may be a | |
169 | // forwarder. First remove all non-common symbols. | |
170 | bool any = false; | |
171 | uint64_t addralign = 0; | |
155a0dd7 ILT |
172 | for (Commons_type::iterator p = commons->begin(); |
173 | p != commons->end(); | |
ead1e424 ILT |
174 | ++p) |
175 | { | |
176 | Symbol* sym = *p; | |
177 | if (sym->is_forwarder()) | |
178 | { | |
179 | sym = this->resolve_forwards(sym); | |
180 | *p = sym; | |
181 | } | |
182 | if (!sym->is_common()) | |
183 | *p = NULL; | |
184 | else | |
185 | { | |
186 | any = true; | |
7d1a9ebb | 187 | Sized_symbol<size>* ssym = this->get_sized_symbol<size>(sym); |
ead1e424 ILT |
188 | if (ssym->value() > addralign) |
189 | addralign = ssym->value(); | |
190 | } | |
191 | } | |
192 | if (!any) | |
193 | return; | |
194 | ||
195 | // Sort the common symbols by size, so that they pack better into | |
196 | // memory. | |
155a0dd7 | 197 | std::sort(commons->begin(), commons->end(), |
ead1e424 ILT |
198 | Sort_commons<size>(this)); |
199 | ||
155a0dd7 | 200 | // Place them in a newly allocated BSS section. |
ead1e424 | 201 | |
7d9e3d98 ILT |
202 | Output_data_space *poc = new Output_data_space(addralign, |
203 | (is_tls | |
204 | ? "** tls common" | |
205 | : "** common")); | |
ead1e424 | 206 | |
155a0dd7 ILT |
207 | const char* name = ".bss"; |
208 | elfcpp::Elf_Xword flags = elfcpp::SHF_WRITE | elfcpp::SHF_ALLOC; | |
209 | if (is_tls) | |
210 | { | |
211 | name = ".tbss"; | |
212 | flags |= elfcpp::SHF_TLS; | |
213 | } | |
214 | layout->add_output_section_data(name, elfcpp::SHT_NOBITS, flags, poc); | |
ead1e424 ILT |
215 | |
216 | // Allocate them all. | |
217 | ||
218 | off_t off = 0; | |
155a0dd7 ILT |
219 | for (Commons_type::iterator p = commons->begin(); |
220 | p != commons->end(); | |
ead1e424 ILT |
221 | ++p) |
222 | { | |
223 | Symbol* sym = *p; | |
224 | if (sym == NULL) | |
225 | break; | |
7d1a9ebb | 226 | Sized_symbol<size>* ssym = this->get_sized_symbol<size>(sym); |
7d9e3d98 ILT |
227 | |
228 | // Record the symbol in the map file now, before we change its | |
229 | // value. Pass the size in separately so that we don't have to | |
230 | // templatize the map code, which is not performance sensitive. | |
231 | if (mapfile != NULL) | |
232 | mapfile->report_allocate_common(sym, ssym->symsize()); | |
233 | ||
ead1e424 | 234 | off = align_address(off, ssym->value()); |
c7912668 | 235 | ssym->allocate_common(poc, off); |
c7912668 | 236 | off += ssym->symsize(); |
ead1e424 ILT |
237 | } |
238 | ||
27bc2bce | 239 | poc->set_current_data_size(off); |
ead1e424 | 240 | |
155a0dd7 | 241 | commons->clear(); |
ead1e424 ILT |
242 | } |
243 | ||
244 | } // End namespace gold. |