| // common.cc -- handle common symbols for gold |
| |
| // Copyright 2006, 2007, 2008 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 "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. |
| |
| 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. |
| |
| void |
| Allocate_commons_task::locks(Task_locker* tl) |
| { |
| tl->add(this, this->blocker_); |
| tl->add(this, this->symtab_lock_); |
| } |
| |
| // Allocate the common symbols. |
| |
| void |
| Allocate_commons_task::run(Workqueue*) |
| { |
| this->symtab_->allocate_commons(this->layout_); |
| } |
| |
| // This class is used to sort the common symbol by size. We put the |
| // larger common symbols first. |
| |
| template<int size> |
| class Sort_commons |
| { |
| public: |
| Sort_commons(const Symbol_table* symtab) |
| : symtab_(symtab) |
| { } |
| |
| bool operator()(const Symbol* a, const Symbol* b) const; |
| |
| private: |
| const Symbol_table* symtab_; |
| }; |
| |
| template<int size> |
| bool |
| Sort_commons<size>::operator()(const Symbol* pa, const Symbol* pb) const |
| { |
| if (pa == NULL) |
| return false; |
| if (pb == NULL) |
| return true; |
| |
| const Symbol_table* symtab = this->symtab_; |
| 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. |
| typename Sized_symbol<size>::Size_type sa = psa->symsize(); |
| typename Sized_symbol<size>::Size_type sb = psb->symsize(); |
| 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; |
| |
| // 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(Layout* layout) |
| { |
| if (parameters->target().get_size() == 32) |
| { |
| #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG) |
| this->do_allocate_commons<32>(layout); |
| #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); |
| #else |
| gold_unreachable(); |
| #endif |
| } |
| else |
| gold_unreachable(); |
| } |
| |
| // Allocated the common symbols, sized version. |
| |
| template<int size> |
| void |
| Symbol_table::do_allocate_commons(Layout* layout) |
| { |
| this->do_allocate_commons_list<size>(layout, false, &this->commons_); |
| this->do_allocate_commons_list<size>(layout, true, &this->tls_commons_); |
| } |
| |
| // 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, bool is_tls, |
| Commons_type* commons) |
| { |
| 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. |
| bool any = false; |
| uint64_t addralign = 0; |
| for (Commons_type::iterator p = commons->begin(); |
| p != commons->end(); |
| ++p) |
| { |
| Symbol* sym = *p; |
| if (sym->is_forwarder()) |
| { |
| sym = this->resolve_forwards(sym); |
| *p = sym; |
| } |
| if (!sym->is_common()) |
| *p = NULL; |
| else |
| { |
| any = true; |
| 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(commons->begin(), commons->end(), |
| Sort_commons<size>(this)); |
| |
| // Place them in a newly allocated BSS section. |
| |
| Output_data_space *poc = new Output_data_space(addralign); |
| |
| const char* name = ".bss"; |
| elfcpp::Elf_Xword flags = elfcpp::SHF_WRITE | elfcpp::SHF_ALLOC; |
| if (is_tls) |
| { |
| name = ".tbss"; |
| flags |= elfcpp::SHF_TLS; |
| } |
| layout->add_output_section_data(name, elfcpp::SHT_NOBITS, flags, poc); |
| |
| // Allocate them all. |
| |
| off_t off = 0; |
| for (Commons_type::iterator p = commons->begin(); |
| p != commons->end(); |
| ++p) |
| { |
| Symbol* sym = *p; |
| if (sym == NULL) |
| break; |
| Sized_symbol<size>* ssym = this->get_sized_symbol<size>(sym); |
| off = align_address(off, ssym->value()); |
| ssym->allocate_common(poc, off); |
| off += ssym->symsize(); |
| } |
| |
| poc->set_current_data_size(off); |
| |
| commons->clear(); |
| } |
| |
| } // End namespace gold. |