* elf32-spu.c (build_stub): Fix malloc under-allocation.
[binutils.git] / gold / common.cc
blob1a9aea871cee91d7ea4f110b8aa47b99f01a9236
1 // common.cc -- handle common symbols for gold
3 // Copyright 2006, 2007, 2008, 2009, 2010 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.
23 #include "gold.h"
25 #include <algorithm>
27 #include "workqueue.h"
28 #include "mapfile.h"
29 #include "layout.h"
30 #include "output.h"
31 #include "symtab.h"
32 #include "common.h"
34 namespace gold
37 // Allocate_commons_task methods.
39 // This task allocates the common symbols. We arrange to run it
40 // before anything else which needs to access the symbol table.
42 Task_token*
43 Allocate_commons_task::is_runnable()
45 return NULL;
48 // Release a blocker.
50 void
51 Allocate_commons_task::locks(Task_locker* tl)
53 tl->add(this, this->blocker_);
56 // Allocate the common symbols.
58 void
59 Allocate_commons_task::run(Workqueue*)
61 this->symtab_->allocate_commons(this->layout_, this->mapfile_);
64 // This class is used to sort the common symbol. We normally put the
65 // larger common symbols first. This can be changed by using
66 // --sort-commons, which tells the linker to sort by alignment.
68 template<int size>
69 class Sort_commons
71 public:
72 Sort_commons(const Symbol_table* symtab,
73 Symbol_table::Sort_commons_order sort_order)
74 : symtab_(symtab), sort_order_(sort_order)
75 { }
77 bool operator()(const Symbol* a, const Symbol* b) const;
79 private:
80 // The symbol table.
81 const Symbol_table* symtab_;
82 // How to sort.
83 Symbol_table::Sort_commons_order sort_order_;
86 template<int size>
87 bool
88 Sort_commons<size>::operator()(const Symbol* pa, const Symbol* pb) const
90 if (pa == NULL)
91 return false;
92 if (pb == NULL)
93 return true;
95 const Symbol_table* symtab = this->symtab_;
96 const Sized_symbol<size>* psa = symtab->get_sized_symbol<size>(pa);
97 const Sized_symbol<size>* psb = symtab->get_sized_symbol<size>(pb);
99 // The size.
100 typename Sized_symbol<size>::Size_type sa = psa->symsize();
101 typename Sized_symbol<size>::Size_type sb = psb->symsize();
103 // The alignment.
104 typename Sized_symbol<size>::Value_type aa = psa->value();
105 typename Sized_symbol<size>::Value_type ab = psb->value();
107 if (this->sort_order_ == Symbol_table::SORT_COMMONS_BY_ALIGNMENT_DESCENDING)
109 if (aa < ab)
110 return false;
111 else if (ab < aa)
112 return true;
114 else if (this->sort_order_
115 == Symbol_table::SORT_COMMONS_BY_ALIGNMENT_ASCENDING)
117 if (aa < ab)
118 return true;
119 else if (ab < aa)
120 return false;
122 else
123 gold_assert(this->sort_order_
124 == Symbol_table::SORT_COMMONS_BY_SIZE_DESCENDING);
126 // Sort by descending size.
127 if (sa < sb)
128 return false;
129 else if (sb < sa)
130 return true;
132 if (this->sort_order_ == Symbol_table::SORT_COMMONS_BY_SIZE_DESCENDING)
134 // When the symbols are the same size, we sort them by
135 // alignment, largest alignment first.
136 if (aa < ab)
137 return false;
138 else if (ab < aa)
139 return true;
142 // Otherwise we stabilize the sort by sorting by name.
143 return strcmp(psa->name(), psb->name()) < 0;
146 // Allocate the common symbols.
148 void
149 Symbol_table::allocate_commons(Layout* layout, Mapfile* mapfile)
151 Sort_commons_order sort_order;
152 if (!parameters->options().user_set_sort_common())
153 sort_order = SORT_COMMONS_BY_SIZE_DESCENDING;
154 else
156 const char* order = parameters->options().sort_common();
157 if (*order == '\0' || strcmp(order, "descending") == 0)
158 sort_order = SORT_COMMONS_BY_ALIGNMENT_DESCENDING;
159 else if (strcmp(order, "ascending") == 0)
160 sort_order = SORT_COMMONS_BY_ALIGNMENT_ASCENDING;
161 else
163 gold_error("invalid --sort-common argument: %s", order);
164 sort_order = SORT_COMMONS_BY_SIZE_DESCENDING;
168 if (parameters->target().get_size() == 32)
170 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
171 this->do_allocate_commons<32>(layout, mapfile, sort_order);
172 #else
173 gold_unreachable();
174 #endif
176 else if (parameters->target().get_size() == 64)
178 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
179 this->do_allocate_commons<64>(layout, mapfile, sort_order);
180 #else
181 gold_unreachable();
182 #endif
184 else
185 gold_unreachable();
188 // Allocated the common symbols, sized version.
190 template<int size>
191 void
192 Symbol_table::do_allocate_commons(Layout* layout, Mapfile* mapfile,
193 Sort_commons_order sort_order)
195 if (!this->commons_.empty())
196 this->do_allocate_commons_list<size>(layout, COMMONS_NORMAL,
197 &this->commons_, mapfile,
198 sort_order);
199 if (!this->tls_commons_.empty())
200 this->do_allocate_commons_list<size>(layout, COMMONS_TLS,
201 &this->tls_commons_, mapfile,
202 sort_order);
203 if (!this->small_commons_.empty())
204 this->do_allocate_commons_list<size>(layout, COMMONS_SMALL,
205 &this->small_commons_, mapfile,
206 sort_order);
207 if (!this->large_commons_.empty())
208 this->do_allocate_commons_list<size>(layout, COMMONS_LARGE,
209 &this->large_commons_, mapfile,
210 sort_order);
213 // Allocate the common symbols in a list. IS_TLS indicates whether
214 // these are TLS common symbols.
216 template<int size>
217 void
218 Symbol_table::do_allocate_commons_list(
219 Layout* layout,
220 Commons_section_type commons_section_type,
221 Commons_type* commons,
222 Mapfile* mapfile,
223 Sort_commons_order sort_order)
225 typedef typename Sized_symbol<size>::Value_type Value_type;
226 typedef typename Sized_symbol<size>::Size_type Size_type;
228 // We've kept a list of all the common symbols. But the symbol may
229 // have been resolved to a defined symbol by now. And it may be a
230 // forwarder. First remove all non-common symbols.
231 bool any = false;
232 uint64_t addralign = 0;
233 for (Commons_type::iterator p = commons->begin();
234 p != commons->end();
235 ++p)
237 Symbol* sym = *p;
238 if (sym->is_forwarder())
240 sym = this->resolve_forwards(sym);
241 *p = sym;
243 if (!sym->is_common())
244 *p = NULL;
245 else
247 any = true;
248 Sized_symbol<size>* ssym = this->get_sized_symbol<size>(sym);
249 if (ssym->value() > addralign)
250 addralign = ssym->value();
253 if (!any)
254 return;
256 // Sort the common symbols.
257 std::sort(commons->begin(), commons->end(),
258 Sort_commons<size>(this, sort_order));
260 // Place them in a newly allocated BSS section.
261 elfcpp::Elf_Xword flags = elfcpp::SHF_WRITE | elfcpp::SHF_ALLOC;
262 const char* name;
263 const char* ds_name;
264 switch (commons_section_type)
266 case COMMONS_NORMAL:
267 name = ".bss";
268 ds_name = "** common";
269 break;
270 case COMMONS_TLS:
271 flags |= elfcpp::SHF_TLS;
272 name = ".tbss";
273 ds_name = "** tls common";
274 break;
275 case COMMONS_SMALL:
276 flags |= parameters->target().small_common_section_flags();
277 name = ".sbss";
278 ds_name = "** small common";
279 break;
280 case COMMONS_LARGE:
281 flags |= parameters->target().large_common_section_flags();
282 name = ".lbss";
283 ds_name = "** large common";
284 break;
285 default:
286 gold_unreachable();
289 Output_data_space* poc;
290 Output_section* os;
292 if (!parameters->incremental_update())
294 poc = new Output_data_space(addralign, ds_name);
295 os = layout->add_output_section_data(name, elfcpp::SHT_NOBITS, flags,
296 poc, ORDER_INVALID, false);
298 else
300 // When doing an incremental update, we need to allocate each common
301 // directly from the output section's free list.
302 poc = NULL;
303 os = layout->find_output_section(name);
306 if (os != NULL)
308 if (commons_section_type == COMMONS_SMALL)
309 os->set_is_small_section();
310 else if (commons_section_type == COMMONS_LARGE)
311 os->set_is_large_section();
314 // Allocate them all.
316 off_t off = 0;
317 for (Commons_type::iterator p = commons->begin();
318 p != commons->end();
319 ++p)
321 Symbol* sym = *p;
322 if (sym == NULL)
323 break;
325 // Because we followed forwarding symbols above, but we didn't
326 // do it reliably before adding symbols to the list, it is
327 // possible for us to have the same symbol on the list twice.
328 // This can happen in the horrible case where a program defines
329 // a common symbol with the same name as a versioned libc
330 // symbol. That will show up here as a symbol which has already
331 // been allocated and is therefore no longer a common symbol.
332 if (!sym->is_common())
333 continue;
335 Sized_symbol<size>* ssym = this->get_sized_symbol<size>(sym);
337 // Record the symbol in the map file now, before we change its
338 // value. Pass the size in separately so that we don't have to
339 // templatize the map code, which is not performance sensitive.
340 if (mapfile != NULL)
341 mapfile->report_allocate_common(sym, ssym->symsize());
343 if (poc != NULL)
345 off = align_address(off, ssym->value());
346 ssym->allocate_common(poc, off);
347 off += ssym->symsize();
349 else
351 // For an incremental update, allocate from the free list.
352 off = os->allocate(ssym->symsize(), ssym->value());
353 if (off == -1)
354 gold_fallback(_("out of patch space in section %s; "
355 "relink with --incremental-full"),
356 os->name());
357 ssym->allocate_common(os, off);
361 if (poc != NULL)
362 poc->set_current_data_size(off);
364 commons->clear();
367 } // End namespace gold.