1 // common.cc -- handle common symbols for gold
3 // Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
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.
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.
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.
27 #include "workqueue.h"
37 // Allocate_commons_task methods.
39 // This task allocates the common symbols. We need a lock on the
43 Allocate_commons_task::is_runnable()
45 if (!this->symtab_lock_
->is_writable())
46 return this->symtab_lock_
;
50 // Return the locks we hold: one on the symbol table, and one blocker.
53 Allocate_commons_task::locks(Task_locker
* tl
)
55 tl
->add(this, this->blocker_
);
56 tl
->add(this, this->symtab_lock_
);
59 // Allocate the common symbols.
62 Allocate_commons_task::run(Workqueue
*)
64 this->symtab_
->allocate_commons(this->layout_
, this->mapfile_
);
67 // This class is used to sort the common symbol by size. We put the
68 // larger common symbols first.
74 Sort_commons(const Symbol_table
* symtab
)
78 bool operator()(const Symbol
* a
, const Symbol
* b
) const;
81 const Symbol_table
* symtab_
;
86 Sort_commons
<size
>::operator()(const Symbol
* pa
, const Symbol
* pb
) const
93 const Symbol_table
* symtab
= this->symtab_
;
94 const Sized_symbol
<size
>* psa
= symtab
->get_sized_symbol
<size
>(pa
);
95 const Sized_symbol
<size
>* psb
= symtab
->get_sized_symbol
<size
>(pb
);
97 // Sort by largest size first.
98 typename Sized_symbol
<size
>::Size_type sa
= psa
->symsize();
99 typename Sized_symbol
<size
>::Size_type sb
= psb
->symsize();
105 // When the symbols are the same size, we sort them by alignment,
106 // largest alignment first.
107 typename Sized_symbol
<size
>::Value_type va
= psa
->value();
108 typename Sized_symbol
<size
>::Value_type vb
= psb
->value();
114 // Otherwise we stabilize the sort by sorting by name.
115 return strcmp(psa
->name(), psb
->name()) < 0;
118 // Allocate the common symbols.
121 Symbol_table::allocate_commons(Layout
* layout
, Mapfile
* mapfile
)
123 if (parameters
->target().get_size() == 32)
125 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
126 this->do_allocate_commons
<32>(layout
, mapfile
);
131 else if (parameters
->target().get_size() == 64)
133 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
134 this->do_allocate_commons
<64>(layout
, mapfile
);
143 // Allocated the common symbols, sized version.
147 Symbol_table::do_allocate_commons(Layout
* layout
, Mapfile
* mapfile
)
149 this->do_allocate_commons_list
<size
>(layout
, false, &this->commons_
,
151 this->do_allocate_commons_list
<size
>(layout
, true, &this->tls_commons_
,
155 // Allocate the common symbols in a list. IS_TLS indicates whether
156 // these are TLS common symbols.
160 Symbol_table::do_allocate_commons_list(Layout
* layout
, bool is_tls
,
161 Commons_type
* commons
,
164 typedef typename Sized_symbol
<size
>::Value_type Value_type
;
165 typedef typename Sized_symbol
<size
>::Size_type Size_type
;
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.
171 uint64_t addralign
= 0;
172 for (Commons_type::iterator p
= commons
->begin();
177 if (sym
->is_forwarder())
179 sym
= this->resolve_forwards(sym
);
182 if (!sym
->is_common())
187 Sized_symbol
<size
>* ssym
= this->get_sized_symbol
<size
>(sym
);
188 if (ssym
->value() > addralign
)
189 addralign
= ssym
->value();
195 // Sort the common symbols by size, so that they pack better into
197 std::sort(commons
->begin(), commons
->end(),
198 Sort_commons
<size
>(this));
200 // Place them in a newly allocated BSS section.
202 Output_data_space
*poc
= new Output_data_space(addralign
,
207 const char* name
= ".bss";
208 elfcpp::Elf_Xword flags
= elfcpp::SHF_WRITE
| elfcpp::SHF_ALLOC
;
212 flags
|= elfcpp::SHF_TLS
;
214 layout
->add_output_section_data(name
, elfcpp::SHT_NOBITS
, flags
, poc
);
216 // Allocate them all.
219 for (Commons_type::iterator p
= commons
->begin();
226 Sized_symbol
<size
>* ssym
= this->get_sized_symbol
<size
>(sym
);
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.
232 mapfile
->report_allocate_common(sym
, ssym
->symsize());
234 off
= align_address(off
, ssym
->value());
235 ssym
->allocate_common(poc
, off
);
236 off
+= ssym
->symsize();
239 poc
->set_current_data_size(off
);
244 } // End namespace gold.
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