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ead1e424 ILT |
1 | // common.cc -- handle common symbols for gold |
2 | ||
3 | #include "gold.h" | |
4 | ||
5 | #include <algorithm> | |
6 | ||
7 | #include "workqueue.h" | |
8 | #include "layout.h" | |
9 | #include "output.h" | |
10 | #include "common.h" | |
11 | ||
12 | namespace gold | |
13 | { | |
14 | ||
15 | // Allocate_commons_task methods. | |
16 | ||
17 | // This task allocates the common symbols. We need a lock on the | |
18 | // symbol table. | |
19 | ||
20 | Task::Is_runnable_type | |
21 | Allocate_commons_task::is_runnable(Workqueue*) | |
22 | { | |
23 | if (!this->symtab_lock_->is_writable()) | |
24 | return IS_LOCKED; | |
25 | return IS_RUNNABLE; | |
26 | } | |
27 | ||
28 | // Return the locks we hold: one on the symbol table, and one blocker. | |
29 | ||
30 | class Allocate_commons_task::Allocate_commons_locker : public Task_locker | |
31 | { | |
32 | public: | |
33 | Allocate_commons_locker(Task_token& symtab_lock, Task* task, | |
34 | Task_token& blocker, Workqueue* workqueue) | |
35 | : symtab_locker_(symtab_lock, task), | |
36 | blocker_(blocker, workqueue) | |
37 | { } | |
38 | ||
39 | private: | |
40 | Task_locker_write symtab_locker_; | |
41 | Task_locker_block blocker_; | |
42 | }; | |
43 | ||
44 | Task_locker* | |
45 | Allocate_commons_task::locks(Workqueue* workqueue) | |
46 | { | |
47 | return new Allocate_commons_locker(*this->symtab_lock_, this, | |
48 | *this->blocker_, workqueue); | |
49 | } | |
50 | ||
51 | // Allocate the common symbols. | |
52 | ||
53 | void | |
54 | Allocate_commons_task::run(Workqueue*) | |
55 | { | |
56 | this->symtab_->allocate_commons(this->options_, this->layout_); | |
57 | } | |
58 | ||
59 | // This class is used to sort the common symbol by size. We put the | |
60 | // larger common symbols first. | |
61 | ||
62 | template<int size> | |
63 | class Sort_commons | |
64 | { | |
65 | public: | |
66 | Sort_commons(const Symbol_table* symtab) | |
67 | : symtab_(symtab) | |
68 | { } | |
69 | ||
70 | bool operator()(const Symbol* a, const Symbol* b) const; | |
71 | ||
72 | private: | |
73 | const Symbol_table* symtab_; | |
74 | }; | |
75 | ||
76 | template<int size> | |
77 | bool | |
78 | Sort_commons<size>::operator()(const Symbol* pa, const Symbol* pb) const | |
79 | { | |
80 | if (pa == NULL) | |
81 | return false; | |
82 | if (pb == NULL) | |
83 | return true; | |
84 | ||
85 | const Symbol_table* symtab = this->symtab_; | |
86 | const Sized_symbol<size>* psa; | |
87 | psa = symtab->get_sized_symbol SELECT_SIZE_NAME (pa | |
88 | SELECT_SIZE(size)); | |
89 | const Sized_symbol<size>* psb; | |
90 | psb = symtab->get_sized_symbol SELECT_SIZE_NAME (pb | |
91 | SELECT_SIZE(size)); | |
92 | ||
93 | typename Sized_symbol<size>::Size_type sa = psa->symsize(); | |
94 | typename Sized_symbol<size>::Size_type sb = psb->symsize(); | |
95 | if (sa < sb) | |
96 | return false; | |
97 | else if (sb > sa) | |
98 | return true; | |
99 | ||
100 | // When the symbols are the same size, we sort them by alignment. | |
101 | typename Sized_symbol<size>::Value_type va = psa->value(); | |
102 | typename Sized_symbol<size>::Value_type vb = psb->value(); | |
103 | if (va < vb) | |
104 | return false; | |
105 | else if (vb > va) | |
106 | return true; | |
107 | ||
108 | // Otherwise we stabilize the sort by sorting by name. | |
109 | return strcmp(psa->name(), psb->name()) < 0; | |
110 | } | |
111 | ||
112 | // Allocate the common symbols. | |
113 | ||
114 | void | |
115 | Symbol_table::allocate_commons(const General_options& options, Layout* layout) | |
116 | { | |
117 | if (this->get_size() == 32) | |
118 | this->do_allocate_commons<32>(options, layout); | |
119 | else if (this->get_size() == 64) | |
120 | this->do_allocate_commons<64>(options, layout); | |
121 | else | |
122 | abort(); | |
123 | } | |
124 | ||
125 | // Allocated the common symbols, sized version. | |
126 | ||
127 | template<int size> | |
128 | void | |
129 | Symbol_table::do_allocate_commons(const General_options&, | |
130 | Layout* layout) | |
131 | { | |
132 | typedef typename Sized_symbol<size>::Value_type Value_type; | |
133 | typedef typename Sized_symbol<size>::Size_type Size_type; | |
134 | ||
135 | // We've kept a list of all the common symbols. But the symbol may | |
136 | // have been resolved to a defined symbol by now. And it may be a | |
137 | // forwarder. First remove all non-common symbols. | |
138 | bool any = false; | |
139 | uint64_t addralign = 0; | |
140 | for (Commons_type::iterator p = this->commons_.begin(); | |
141 | p != this->commons_.end(); | |
142 | ++p) | |
143 | { | |
144 | Symbol* sym = *p; | |
145 | if (sym->is_forwarder()) | |
146 | { | |
147 | sym = this->resolve_forwards(sym); | |
148 | *p = sym; | |
149 | } | |
150 | if (!sym->is_common()) | |
151 | *p = NULL; | |
152 | else | |
153 | { | |
154 | any = true; | |
155 | Sized_symbol<size>* ssym; | |
156 | ssym = this->get_sized_symbol SELECT_SIZE_NAME (sym | |
157 | SELECT_SIZE(size)); | |
158 | if (ssym->value() > addralign) | |
159 | addralign = ssym->value(); | |
160 | } | |
161 | } | |
162 | if (!any) | |
163 | return; | |
164 | ||
165 | // Sort the common symbols by size, so that they pack better into | |
166 | // memory. | |
167 | std::sort(this->commons_.begin(), this->commons_.end(), | |
168 | Sort_commons<size>(this)); | |
169 | ||
170 | // Place them in a newly allocated .bss section. | |
171 | ||
172 | Output_section_common *poc = new Output_section_common(addralign); | |
173 | ||
174 | layout->add_output_section_data(".bss", elfcpp::SHT_NOBITS, | |
175 | elfcpp::SHF_WRITE | elfcpp::SHF_ALLOC, | |
176 | poc); | |
177 | ||
178 | // Allocate them all. | |
179 | ||
180 | off_t off = 0; | |
181 | for (Commons_type::iterator p = this->commons_.begin(); | |
182 | p != this->commons_.end(); | |
183 | ++p) | |
184 | { | |
185 | Symbol* sym = *p; | |
186 | if (sym == NULL) | |
187 | break; | |
188 | ||
189 | Sized_symbol<size>* ssym; | |
190 | ssym = this->get_sized_symbol SELECT_SIZE_NAME (sym | |
191 | SELECT_SIZE(size)); | |
192 | ||
193 | off = align_address(off, ssym->value()); | |
194 | ||
195 | Size_type symsize = ssym->symsize(); | |
196 | ssym->init(ssym->name(), poc, off, symsize, ssym->type(), | |
197 | ssym->binding(), ssym->visibility(), ssym->nonvis(), | |
198 | false); | |
199 | ||
200 | off += symsize; | |
201 | } | |
202 | ||
203 | poc->set_common_size(off); | |
204 | ||
205 | this->commons_.clear(); | |
206 | } | |
207 | ||
208 | } // End namespace gold. |