// common.cc -- handle common symbols for gold
+// Copyright (C) 2006-2020 Free Software Foundation, Inc.
+// Written by Ian Lance Taylor <iant@google.com>.
+
+// This file is part of gold.
+
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
+// MA 02110-1301, USA.
+
#include "gold.h"
#include <algorithm>
#include "workqueue.h"
+#include "mapfile.h"
#include "layout.h"
#include "output.h"
+#include "symtab.h"
#include "common.h"
namespace gold
// Allocate_commons_task methods.
-// This task allocates the common symbols. We need a lock on the
-// symbol table.
+// This task allocates the common symbols. We arrange to run it
+// before anything else which needs to access the symbol table.
-Task::Is_runnable_type
-Allocate_commons_task::is_runnable(Workqueue*)
+Task_token*
+Allocate_commons_task::is_runnable()
{
- if (!this->symtab_lock_->is_writable())
- return IS_LOCKED;
- return IS_RUNNABLE;
+ return NULL;
}
-// Return the locks we hold: one on the symbol table, and one blocker.
+// Release a blocker.
-class Allocate_commons_task::Allocate_commons_locker : public Task_locker
-{
- public:
- Allocate_commons_locker(Task_token& symtab_lock, Task* task,
- Task_token& blocker, Workqueue* workqueue)
- : symtab_locker_(symtab_lock, task),
- blocker_(blocker, workqueue)
- { }
-
- private:
- Task_locker_write symtab_locker_;
- Task_locker_block blocker_;
-};
-
-Task_locker*
-Allocate_commons_task::locks(Workqueue* workqueue)
+void
+Allocate_commons_task::locks(Task_locker* tl)
{
- return new Allocate_commons_locker(*this->symtab_lock_, this,
- *this->blocker_, workqueue);
+ tl->add(this, this->blocker_);
}
// Allocate the common symbols.
void
Allocate_commons_task::run(Workqueue*)
{
- this->symtab_->allocate_commons(this->options_, this->layout_);
+ this->symtab_->allocate_commons(this->layout_, this->mapfile_);
}
-// This class is used to sort the common symbol by size. We put the
-// larger common symbols first.
+// This class is used to sort the common symbol. We normally put the
+// larger common symbols first. This can be changed by using
+// --sort-commons, which tells the linker to sort by alignment.
template<int size>
class Sort_commons
{
public:
- Sort_commons(const Symbol_table* symtab)
- : symtab_(symtab)
+ Sort_commons(const Symbol_table* symtab,
+ Symbol_table::Sort_commons_order sort_order)
+ : symtab_(symtab), sort_order_(sort_order)
{ }
bool operator()(const Symbol* a, const Symbol* b) const;
private:
+ // The symbol table.
const Symbol_table* symtab_;
+ // How to sort.
+ Symbol_table::Sort_commons_order sort_order_;
};
template<int size>
return true;
const Symbol_table* symtab = this->symtab_;
- const Sized_symbol<size>* psa;
- psa = symtab->get_sized_symbol SELECT_SIZE_NAME(size) (pa
- SELECT_SIZE(size));
- const Sized_symbol<size>* psb;
- psb = symtab->get_sized_symbol SELECT_SIZE_NAME(size) (pb
- SELECT_SIZE(size));
+ const Sized_symbol<size>* psa = symtab->get_sized_symbol<size>(pa);
+ const Sized_symbol<size>* psb = symtab->get_sized_symbol<size>(pb);
+ // The size.
typename Sized_symbol<size>::Size_type sa = psa->symsize();
typename Sized_symbol<size>::Size_type sb = psb->symsize();
+
+ // The alignment.
+ typename Sized_symbol<size>::Value_type aa = psa->value();
+ typename Sized_symbol<size>::Value_type ab = psb->value();
+
+ if (this->sort_order_ == Symbol_table::SORT_COMMONS_BY_ALIGNMENT_DESCENDING)
+ {
+ if (aa < ab)
+ return false;
+ else if (ab < aa)
+ return true;
+ }
+ else if (this->sort_order_
+ == Symbol_table::SORT_COMMONS_BY_ALIGNMENT_ASCENDING)
+ {
+ if (aa < ab)
+ return true;
+ else if (ab < aa)
+ return false;
+ }
+ else
+ gold_assert(this->sort_order_
+ == Symbol_table::SORT_COMMONS_BY_SIZE_DESCENDING);
+
+ // Sort by descending size.
if (sa < sb)
return false;
- else if (sb > sa)
+ else if (sb < sa)
return true;
- // When the symbols are the same size, we sort them by alignment.
- typename Sized_symbol<size>::Value_type va = psa->value();
- typename Sized_symbol<size>::Value_type vb = psb->value();
- if (va < vb)
- return false;
- else if (vb > va)
- return true;
+ if (this->sort_order_ == Symbol_table::SORT_COMMONS_BY_SIZE_DESCENDING)
+ {
+ // When the symbols are the same size, we sort them by
+ // alignment, largest alignment first.
+ if (aa < ab)
+ return false;
+ else if (ab < aa)
+ return true;
+ }
// Otherwise we stabilize the sort by sorting by name.
return strcmp(psa->name(), psb->name()) < 0;
// Allocate the common symbols.
void
-Symbol_table::allocate_commons(const General_options& options, Layout* layout)
+Symbol_table::allocate_commons(Layout* layout, Mapfile* mapfile)
{
- if (this->get_size() == 32)
- this->do_allocate_commons<32>(options, layout);
- else if (this->get_size() == 64)
- this->do_allocate_commons<64>(options, layout);
+ Sort_commons_order sort_order;
+ if (!parameters->options().user_set_sort_common())
+ sort_order = SORT_COMMONS_BY_SIZE_DESCENDING;
else
- abort();
+ {
+ const char* order = parameters->options().sort_common();
+ if (*order == '\0' || strcmp(order, "descending") == 0)
+ sort_order = SORT_COMMONS_BY_ALIGNMENT_DESCENDING;
+ else if (strcmp(order, "ascending") == 0)
+ sort_order = SORT_COMMONS_BY_ALIGNMENT_ASCENDING;
+ else
+ {
+ gold_error("invalid --sort-common argument: %s", order);
+ sort_order = SORT_COMMONS_BY_SIZE_DESCENDING;
+ }
+ }
+
+ if (parameters->target().get_size() == 32)
+ {
+#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
+ this->do_allocate_commons<32>(layout, mapfile, sort_order);
+#else
+ gold_unreachable();
+#endif
+ }
+ else if (parameters->target().get_size() == 64)
+ {
+#if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
+ this->do_allocate_commons<64>(layout, mapfile, sort_order);
+#else
+ gold_unreachable();
+#endif
+ }
+ else
+ gold_unreachable();
}
// Allocated the common symbols, sized version.
template<int size>
void
-Symbol_table::do_allocate_commons(const General_options&,
- Layout* layout)
+Symbol_table::do_allocate_commons(Layout* layout, Mapfile* mapfile,
+ Sort_commons_order sort_order)
{
- typedef typename Sized_symbol<size>::Value_type Value_type;
- typedef typename Sized_symbol<size>::Size_type Size_type;
+ if (!this->commons_.empty())
+ this->do_allocate_commons_list<size>(layout, COMMONS_NORMAL,
+ &this->commons_, mapfile,
+ sort_order);
+ if (!this->tls_commons_.empty())
+ this->do_allocate_commons_list<size>(layout, COMMONS_TLS,
+ &this->tls_commons_, mapfile,
+ sort_order);
+ if (!this->small_commons_.empty())
+ this->do_allocate_commons_list<size>(layout, COMMONS_SMALL,
+ &this->small_commons_, mapfile,
+ sort_order);
+ if (!this->large_commons_.empty())
+ this->do_allocate_commons_list<size>(layout, COMMONS_LARGE,
+ &this->large_commons_, mapfile,
+ sort_order);
+}
+
+// Allocate the common symbols in a list. IS_TLS indicates whether
+// these are TLS common symbols.
+template<int size>
+void
+Symbol_table::do_allocate_commons_list(
+ Layout* layout,
+ Commons_section_type commons_section_type,
+ Commons_type* commons,
+ Mapfile* mapfile,
+ Sort_commons_order sort_order)
+{
// We've kept a list of all the common symbols. But the symbol may
// have been resolved to a defined symbol by now. And it may be a
// forwarder. First remove all non-common symbols.
bool any = false;
uint64_t addralign = 0;
- for (Commons_type::iterator p = this->commons_.begin();
- p != this->commons_.end();
+ for (Commons_type::iterator p = commons->begin();
+ p != commons->end();
++p)
{
Symbol* sym = *p;
else
{
any = true;
- Sized_symbol<size>* ssym;
- ssym = this->get_sized_symbol SELECT_SIZE_NAME(size) (
- sym
- SELECT_SIZE(size));
+ Sized_symbol<size>* ssym = this->get_sized_symbol<size>(sym);
if (ssym->value() > addralign)
addralign = ssym->value();
}
if (!any)
return;
- // Sort the common symbols by size, so that they pack better into
- // memory.
- std::sort(this->commons_.begin(), this->commons_.end(),
- Sort_commons<size>(this));
+ // Sort the common symbols.
+ std::sort(commons->begin(), commons->end(),
+ Sort_commons<size>(this, sort_order));
+
+ // Place them in a newly allocated BSS section.
+ elfcpp::Elf_Xword flags = elfcpp::SHF_WRITE | elfcpp::SHF_ALLOC;
+ const char* name;
+ const char* ds_name;
+ switch (commons_section_type)
+ {
+ case COMMONS_NORMAL:
+ name = ".bss";
+ ds_name = "** common";
+ break;
+ case COMMONS_TLS:
+ flags |= elfcpp::SHF_TLS;
+ name = ".tbss";
+ ds_name = "** tls common";
+ break;
+ case COMMONS_SMALL:
+ flags |= parameters->target().small_common_section_flags();
+ name = ".sbss";
+ ds_name = "** small common";
+ break;
+ case COMMONS_LARGE:
+ flags |= parameters->target().large_common_section_flags();
+ name = ".lbss";
+ ds_name = "** large common";
+ break;
+ default:
+ gold_unreachable();
+ }
- // Place them in a newly allocated .bss section.
+ Output_data_space* poc;
+ Output_section* os;
- Output_section_common *poc = new Output_section_common(addralign);
+ if (!parameters->incremental_update())
+ {
+ poc = new Output_data_space(addralign, ds_name);
+ os = layout->add_output_section_data(name, elfcpp::SHT_NOBITS, flags,
+ poc, ORDER_INVALID, false);
+ }
+ else
+ {
+ // When doing an incremental update, we need to allocate each common
+ // directly from the output section's free list.
+ poc = NULL;
+ os = layout->find_output_section(name);
+ }
- layout->add_output_section_data(".bss", elfcpp::SHT_NOBITS,
- elfcpp::SHF_WRITE | elfcpp::SHF_ALLOC,
- poc);
+ if (os != NULL)
+ {
+ if (commons_section_type == COMMONS_SMALL)
+ os->set_is_small_section();
+ else if (commons_section_type == COMMONS_LARGE)
+ os->set_is_large_section();
+ }
// Allocate them all.
off_t off = 0;
- for (Commons_type::iterator p = this->commons_.begin();
- p != this->commons_.end();
+ for (Commons_type::iterator p = commons->begin();
+ p != commons->end();
++p)
{
Symbol* sym = *p;
if (sym == NULL)
break;
- Sized_symbol<size>* ssym;
- ssym = this->get_sized_symbol SELECT_SIZE_NAME(size) (sym
- SELECT_SIZE(size));
+ // Because we followed forwarding symbols above, but we didn't
+ // do it reliably before adding symbols to the list, it is
+ // possible for us to have the same symbol on the list twice.
+ // This can happen in the horrible case where a program defines
+ // a common symbol with the same name as a versioned libc
+ // symbol. That will show up here as a symbol which has already
+ // been allocated and is therefore no longer a common symbol.
+ if (!sym->is_common())
+ continue;
- off = align_address(off, ssym->value());
+ Sized_symbol<size>* ssym = this->get_sized_symbol<size>(sym);
- Size_type symsize = ssym->symsize();
- ssym->init(ssym->name(), poc, off, symsize, ssym->type(),
- ssym->binding(), ssym->visibility(), ssym->nonvis(),
- false);
+ // Record the symbol in the map file now, before we change its
+ // value. Pass the size in separately so that we don't have to
+ // templatize the map code, which is not performance sensitive.
+ if (mapfile != NULL)
+ mapfile->report_allocate_common(sym, ssym->symsize());
- off += symsize;
+ if (poc != NULL)
+ {
+ off = align_address(off, ssym->value());
+ ssym->allocate_common(poc, off);
+ off += ssym->symsize();
+ }
+ else
+ {
+ // For an incremental update, allocate from the free list.
+ off = os->allocate(ssym->symsize(), ssym->value());
+ if (off == -1)
+ gold_fallback(_("out of patch space in section %s; "
+ "relink with --incremental-full"),
+ os->name());
+ ssym->allocate_common(os, off);
+ }
}
- poc->set_common_size(off);
+ if (poc != NULL)
+ poc->set_current_data_size(off);
- this->commons_.clear();
+ commons->clear();
}
} // End namespace gold.
projects / deliverable / binutils-gdb.git / blobdiff