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ead1e424 ILT |
1 | // common.cc -- handle common symbols for gold |
2 | ||
6cb15b7f ILT |
3 | // Copyright 2006, 2007 Free Software Foundation, Inc. |
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 | { | |
63 | this->symtab_->allocate_commons(this->options_, this->layout_); | |
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 ILT |
95 | |
96 | typename Sized_symbol<size>::Size_type sa = psa->symsize(); | |
97 | typename Sized_symbol<size>::Size_type sb = psb->symsize(); | |
98 | if (sa < sb) | |
99 | return false; | |
100 | else if (sb > sa) | |
101 | return true; | |
102 | ||
103 | // When the symbols are the same size, we sort them by alignment. | |
104 | typename Sized_symbol<size>::Value_type va = psa->value(); | |
105 | typename Sized_symbol<size>::Value_type vb = psb->value(); | |
106 | if (va < vb) | |
107 | return false; | |
108 | else if (vb > va) | |
109 | return true; | |
110 | ||
111 | // Otherwise we stabilize the sort by sorting by name. | |
112 | return strcmp(psa->name(), psb->name()) < 0; | |
113 | } | |
114 | ||
115 | // Allocate the common symbols. | |
116 | ||
117 | void | |
118 | Symbol_table::allocate_commons(const General_options& options, Layout* layout) | |
119 | { | |
8851ecca | 120 | if (parameters->target().get_size() == 32) |
8ae3da90 ILT |
121 | { |
122 | #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG) | |
123 | this->do_allocate_commons<32>(options, layout); | |
124 | #else | |
125 | gold_unreachable(); | |
126 | #endif | |
127 | } | |
8851ecca | 128 | else if (parameters->target().get_size() == 64) |
8ae3da90 ILT |
129 | { |
130 | #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG) | |
131 | this->do_allocate_commons<64>(options, layout); | |
132 | #else | |
133 | gold_unreachable(); | |
134 | #endif | |
135 | } | |
ead1e424 | 136 | else |
a3ad94ed | 137 | gold_unreachable(); |
ead1e424 ILT |
138 | } |
139 | ||
140 | // Allocated the common symbols, sized version. | |
141 | ||
142 | template<int size> | |
143 | void | |
144 | Symbol_table::do_allocate_commons(const General_options&, | |
145 | Layout* layout) | |
146 | { | |
147 | typedef typename Sized_symbol<size>::Value_type Value_type; | |
148 | typedef typename Sized_symbol<size>::Size_type Size_type; | |
149 | ||
150 | // We've kept a list of all the common symbols. But the symbol may | |
151 | // have been resolved to a defined symbol by now. And it may be a | |
152 | // forwarder. First remove all non-common symbols. | |
153 | bool any = false; | |
154 | uint64_t addralign = 0; | |
155 | for (Commons_type::iterator p = this->commons_.begin(); | |
156 | p != this->commons_.end(); | |
157 | ++p) | |
158 | { | |
159 | Symbol* sym = *p; | |
160 | if (sym->is_forwarder()) | |
161 | { | |
162 | sym = this->resolve_forwards(sym); | |
163 | *p = sym; | |
164 | } | |
165 | if (!sym->is_common()) | |
166 | *p = NULL; | |
167 | else | |
168 | { | |
169 | any = true; | |
7d1a9ebb | 170 | Sized_symbol<size>* ssym = this->get_sized_symbol<size>(sym); |
ead1e424 ILT |
171 | if (ssym->value() > addralign) |
172 | addralign = ssym->value(); | |
173 | } | |
174 | } | |
175 | if (!any) | |
176 | return; | |
177 | ||
178 | // Sort the common symbols by size, so that they pack better into | |
179 | // memory. | |
180 | std::sort(this->commons_.begin(), this->commons_.end(), | |
181 | Sort_commons<size>(this)); | |
182 | ||
183 | // Place them in a newly allocated .bss section. | |
184 | ||
a3ad94ed | 185 | Output_data_space *poc = new Output_data_space(addralign); |
ead1e424 ILT |
186 | |
187 | layout->add_output_section_data(".bss", elfcpp::SHT_NOBITS, | |
188 | elfcpp::SHF_WRITE | elfcpp::SHF_ALLOC, | |
189 | poc); | |
190 | ||
191 | // Allocate them all. | |
192 | ||
193 | off_t off = 0; | |
194 | for (Commons_type::iterator p = this->commons_.begin(); | |
195 | p != this->commons_.end(); | |
196 | ++p) | |
197 | { | |
198 | Symbol* sym = *p; | |
199 | if (sym == NULL) | |
200 | break; | |
7d1a9ebb | 201 | Sized_symbol<size>* ssym = this->get_sized_symbol<size>(sym); |
ead1e424 | 202 | off = align_address(off, ssym->value()); |
c7912668 | 203 | ssym->allocate_common(poc, off); |
c7912668 | 204 | off += ssym->symsize(); |
ead1e424 ILT |
205 | } |
206 | ||
27bc2bce | 207 | poc->set_current_data_size(off); |
ead1e424 ILT |
208 | |
209 | this->commons_.clear(); | |
210 | } | |
211 | ||
212 | } // End namespace gold. |