// common.cc -- handle common symbols for gold
-// Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
+// Copyright (C) 2006-2020 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of 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_token*
Allocate_commons_task::is_runnable()
{
- if (!this->symtab_lock_->is_writable())
- return this->symtab_lock_;
return NULL;
}
-// Return the locks we hold: one on the symbol table, and one blocker.
+// Release a blocker.
void
Allocate_commons_task::locks(Task_locker* tl)
{
tl->add(this, this->blocker_);
- tl->add(this, this->symtab_lock_);
}
// Allocate the common symbols.
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>
const Sized_symbol<size>* psa = symtab->get_sized_symbol<size>(pa);
const Sized_symbol<size>* psb = symtab->get_sized_symbol<size>(pb);
- // Sort by largest size first.
+ // 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)
return true;
- // When the symbols are the same size, we sort them by alignment,
- // largest alignment first.
- 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;
void
Symbol_table::allocate_commons(Layout* layout, Mapfile* mapfile)
{
+ Sort_commons_order sort_order;
+ if (!parameters->options().user_set_sort_common())
+ sort_order = SORT_COMMONS_BY_SIZE_DESCENDING;
+ else
+ {
+ 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);
+ 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);
+ this->do_allocate_commons<64>(layout, mapfile, sort_order);
#else
gold_unreachable();
#endif
template<int size>
void
-Symbol_table::do_allocate_commons(Layout* layout, Mapfile* mapfile)
+Symbol_table::do_allocate_commons(Layout* layout, Mapfile* mapfile,
+ Sort_commons_order sort_order)
{
- this->do_allocate_commons_list<size>(layout, false, &this->commons_,
- mapfile);
- this->do_allocate_commons_list<size>(layout, true, &this->tls_commons_,
- mapfile);
+ 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
template<int size>
void
-Symbol_table::do_allocate_commons_list(Layout* layout, bool is_tls,
- Commons_type* commons,
- Mapfile* mapfile)
+Symbol_table::do_allocate_commons_list(
+ Layout* layout,
+ Commons_section_type commons_section_type,
+ Commons_type* commons,
+ 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;
-
// 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.
if (!any)
return;
- // Sort the common symbols by size, so that they pack better into
- // memory.
+ // Sort the common symbols.
std::sort(commons->begin(), commons->end(),
- Sort_commons<size>(this));
+ Sort_commons<size>(this, sort_order));
// Place them in a newly allocated BSS section.
-
- Output_data_space *poc = new Output_data_space(addralign,
- (is_tls
- ? "** tls common"
- : "** common"));
-
- const char* name = ".bss";
elfcpp::Elf_Xword flags = elfcpp::SHF_WRITE | elfcpp::SHF_ALLOC;
- if (is_tls)
+ const char* name;
+ const char* ds_name;
+ switch (commons_section_type)
{
- name = ".tbss";
+ 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();
+ }
+
+ Output_data_space* poc;
+ Output_section* os;
+
+ 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);
+ }
+
+ 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();
}
- layout->add_output_section_data(name, elfcpp::SHT_NOBITS, flags, poc);
// Allocate them all.
Symbol* sym = *p;
if (sym == NULL)
break;
+
+ // 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;
+
Sized_symbol<size>* ssym = this->get_sized_symbol<size>(sym);
// Record the symbol in the map file now, before we change its
if (mapfile != NULL)
mapfile->report_allocate_common(sym, ssym->symsize());
- off = align_address(off, ssym->value());
- ssym->allocate_common(poc, off);
- off += ssym->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_current_data_size(off);
+ if (poc != NULL)
+ poc->set_current_data_size(off);
commons->clear();
}
projects / deliverable / binutils-gdb.git / blobdiff