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binutils-gdb/gold/incremental.cc

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// inremental.cc -- incremental linking support for gold
// Copyright 2009, 2010 Free Software Foundation, Inc.
// Written by Mikolaj Zalewski <mikolajz@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 <cstdarg>
#include "libiberty.h"
#include "elfcpp.h"
#include "output.h"
#include "symtab.h"
#include "incremental.h"
#include "archive.h"
#include "output.h"
#include "target-select.h"
#include "target.h"
namespace gold {
// Version information. Will change frequently during the development, later
// we could think about backward (and forward?) compatibility.
const unsigned int INCREMENTAL_LINK_VERSION = 1;
// This class manages the .gnu_incremental_inputs section, which holds
// the header information, a directory of input files, and separate
// entries for each input file.
template<int size, bool big_endian>
class Output_section_incremental_inputs : public Output_section_data
{
public:
Output_section_incremental_inputs(const Incremental_inputs* inputs,
const Symbol_table* symtab)
: Output_section_data(size / 8), inputs_(inputs), symtab_(symtab)
{ }
protected:
// Set the final data size.
void
set_final_data_size();
// Write the data to the file.
void
do_write(Output_file*);
// Write to a map file.
void
do_print_to_mapfile(Mapfile* mapfile) const
{ mapfile->print_output_data(this, _("** incremental_inputs")); }
private:
// Write the section header.
unsigned char*
write_header(unsigned char* pov, unsigned int input_file_count,
section_offset_type command_line_offset);
// Write the input file entries.
unsigned char*
write_input_files(unsigned char* oview, unsigned char* pov,
Stringpool* strtab);
// Write the supplemental information blocks.
unsigned char*
write_info_blocks(unsigned char* oview, unsigned char* pov,
Stringpool* strtab, unsigned int* global_syms,
unsigned int global_sym_count);
// Write the contents of the .gnu_incremental_symtab section.
void
write_symtab(unsigned char* pov, unsigned int* global_syms,
unsigned int global_sym_count);
// Write the contents of the .gnu_incremental_got_plt section.
void
write_got_plt(unsigned char* pov, off_t view_size);
// Typedefs for writing the data to the output sections.
typedef elfcpp::Swap<size, big_endian> Swap;
typedef elfcpp::Swap<16, big_endian> Swap16;
typedef elfcpp::Swap<32, big_endian> Swap32;
typedef elfcpp::Swap<64, big_endian> Swap64;
// Sizes of various structures.
static const int sizeof_addr = size / 8;
static const int header_size = 16;
static const int input_entry_size = 24;
// The Incremental_inputs object.
const Incremental_inputs* inputs_;
// The symbol table.
const Symbol_table* symtab_;
};
// Inform the user why we don't do an incremental link. Not called in
// the obvious case of missing output file. TODO: Is this helpful?
void
vexplain_no_incremental(const char* format, va_list args)
{
char* buf = NULL;
if (vasprintf(&buf, format, args) < 0)
gold_nomem();
gold_info(_("the link might take longer: "
"cannot perform incremental link: %s"), buf);
free(buf);
}
void
explain_no_incremental(const char* format, ...)
{
va_list args;
va_start(args, format);
vexplain_no_incremental(format, args);
va_end(args);
}
// Report an error.
void
Incremental_binary::error(const char* format, ...) const
{
va_list args;
va_start(args, format);
// Current code only checks if the file can be used for incremental linking,
// so errors shouldn't fail the build, but only result in a fallback to a
// full build.
// TODO: when we implement incremental editing of the file, we may need a
// flag that will cause errors to be treated seriously.
vexplain_no_incremental(format, args);
va_end(args);
}
// Find the .gnu_incremental_inputs section and related sections.
template<int size, bool big_endian>
bool
Sized_incremental_binary<size, big_endian>::do_find_incremental_inputs_sections(
unsigned int* p_inputs_shndx,
unsigned int* p_symtab_shndx,
unsigned int* p_relocs_shndx,
unsigned int* p_got_plt_shndx,
unsigned int* p_strtab_shndx)
{
unsigned int inputs_shndx =
this->elf_file_.find_section_by_type(elfcpp::SHT_GNU_INCREMENTAL_INPUTS);
if (inputs_shndx == elfcpp::SHN_UNDEF) // Not found.
return false;
unsigned int symtab_shndx =
this->elf_file_.find_section_by_type(elfcpp::SHT_GNU_INCREMENTAL_SYMTAB);
if (symtab_shndx == elfcpp::SHN_UNDEF) // Not found.
return false;
if (this->elf_file_.section_link(symtab_shndx) != inputs_shndx)
return false;
unsigned int relocs_shndx =
this->elf_file_.find_section_by_type(elfcpp::SHT_GNU_INCREMENTAL_RELOCS);
if (relocs_shndx == elfcpp::SHN_UNDEF) // Not found.
return false;
if (this->elf_file_.section_link(relocs_shndx) != inputs_shndx)
return false;
unsigned int got_plt_shndx =
this->elf_file_.find_section_by_type(elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT);
if (got_plt_shndx == elfcpp::SHN_UNDEF) // Not found.
return false;
if (this->elf_file_.section_link(got_plt_shndx) != inputs_shndx)
return false;
unsigned int strtab_shndx = this->elf_file_.section_link(inputs_shndx);
if (strtab_shndx == elfcpp::SHN_UNDEF
|| strtab_shndx > this->elf_file_.shnum()
|| this->elf_file_.section_type(strtab_shndx) != elfcpp::SHT_STRTAB)
return false;
if (p_inputs_shndx != NULL)
*p_inputs_shndx = inputs_shndx;
if (p_symtab_shndx != NULL)
*p_symtab_shndx = symtab_shndx;
if (p_relocs_shndx != NULL)
*p_relocs_shndx = relocs_shndx;
if (p_got_plt_shndx != NULL)
*p_got_plt_shndx = got_plt_shndx;
if (p_strtab_shndx != NULL)
*p_strtab_shndx = strtab_shndx;
return true;
}
// Determine whether an incremental link based on the existing output file
// can be done.
template<int size, bool big_endian>
bool
Sized_incremental_binary<size, big_endian>::do_check_inputs(
Incremental_inputs* incremental_inputs)
{
unsigned int inputs_shndx;
unsigned int symtab_shndx;
unsigned int relocs_shndx;
unsigned int plt_got_shndx;
unsigned int strtab_shndx;
if (!do_find_incremental_inputs_sections(&inputs_shndx, &symtab_shndx,
&relocs_shndx, &plt_got_shndx,
&strtab_shndx))
{
explain_no_incremental(_("no incremental data from previous build"));
return false;
}
Location inputs_location(this->elf_file_.section_contents(inputs_shndx));
Location symtab_location(this->elf_file_.section_contents(symtab_shndx));
Location relocs_location(this->elf_file_.section_contents(relocs_shndx));
Location strtab_location(this->elf_file_.section_contents(strtab_shndx));
View inputs_view(view(inputs_location));
View symtab_view(view(symtab_location));
View relocs_view(view(relocs_location));
View strtab_view(view(strtab_location));
elfcpp::Elf_strtab strtab(strtab_view.data(), strtab_location.data_size);
Incremental_inputs_reader<size, big_endian>
incoming_inputs(inputs_view.data(), strtab);
if (incoming_inputs.version() != INCREMENTAL_LINK_VERSION)
{
explain_no_incremental(_("different version of incremental build data"));
return false;
}
if (incremental_inputs->command_line() != incoming_inputs.command_line())
{
explain_no_incremental(_("command line changed"));
return false;
}
// TODO: compare incremental_inputs->inputs() with entries in data_view.
return true;
}
namespace
{
// Create a Sized_incremental_binary object of the specified size and
// endianness. Fails if the target architecture is not supported.
template<int size, bool big_endian>
Incremental_binary*
make_sized_incremental_binary(Output_file* file,
const elfcpp::Ehdr<size, big_endian>& ehdr)
{
Target* target = select_target(ehdr.get_e_machine(), size, big_endian,
ehdr.get_e_ident()[elfcpp::EI_OSABI],
ehdr.get_e_ident()[elfcpp::EI_ABIVERSION]);
if (target == NULL)
{
explain_no_incremental(_("unsupported ELF machine number %d"),
ehdr.get_e_machine());
return NULL;
}
if (!parameters->target_valid())
set_parameters_target(target);
else if (target != &parameters->target())
gold_error(_("%s: incompatible target"), file->filename());
return new Sized_incremental_binary<size, big_endian>(file, ehdr, target);
}
} // End of anonymous namespace.
// Create an Incremental_binary object for FILE. Returns NULL is this is not
// possible, e.g. FILE is not an ELF file or has an unsupported target. FILE
// should be opened.
Incremental_binary*
open_incremental_binary(Output_file* file)
{
off_t filesize = file->filesize();
int want = elfcpp::Elf_recognizer::max_header_size;
if (filesize < want)
want = filesize;
const unsigned char* p = file->get_input_view(0, want);
if (!elfcpp::Elf_recognizer::is_elf_file(p, want))
{
explain_no_incremental(_("output is not an ELF file."));
return NULL;
}
int size = 0;
bool big_endian = false;
std::string error;
if (!elfcpp::Elf_recognizer::is_valid_header(p, want, &size, &big_endian,
&error))
{
explain_no_incremental(error.c_str());
return NULL;
}
Incremental_binary* result = NULL;
if (size == 32)
{
if (big_endian)
{
#ifdef HAVE_TARGET_32_BIG
result = make_sized_incremental_binary<32, true>(
file, elfcpp::Ehdr<32, true>(p));
#else
explain_no_incremental(_("unsupported file: 32-bit, big-endian"));
#endif
}
else
{
#ifdef HAVE_TARGET_32_LITTLE
result = make_sized_incremental_binary<32, false>(
file, elfcpp::Ehdr<32, false>(p));
#else
explain_no_incremental(_("unsupported file: 32-bit, little-endian"));
#endif
}
}
else if (size == 64)
{
if (big_endian)
{
#ifdef HAVE_TARGET_64_BIG
result = make_sized_incremental_binary<64, true>(
file, elfcpp::Ehdr<64, true>(p));
#else
explain_no_incremental(_("unsupported file: 64-bit, big-endian"));
#endif
}
else
{
#ifdef HAVE_TARGET_64_LITTLE
result = make_sized_incremental_binary<64, false>(
file, elfcpp::Ehdr<64, false>(p));
#else
explain_no_incremental(_("unsupported file: 64-bit, little-endian"));
#endif
}
}
else
gold_unreachable();
return result;
}
// Analyzes the output file to check if incremental linking is possible and
// (to be done) what files need to be relinked.
bool
Incremental_checker::can_incrementally_link_output_file()
{
Output_file output(this->output_name_);
if (!output.open_for_modification())
return false;
Incremental_binary* binary = open_incremental_binary(&output);
if (binary == NULL)
return false;
return binary->check_inputs(this->incremental_inputs_);
}
// Class Incremental_inputs.
// Add the command line to the string table, setting
// command_line_key_. In incremental builds, the command line is
// stored in .gnu_incremental_inputs so that the next linker run can
// check if the command line options didn't change.
void
Incremental_inputs::report_command_line(int argc, const char* const* argv)
{
// Always store 'gold' as argv[0] to avoid a full relink if the user used a
// different path to the linker.
std::string args("gold");
// Copied from collect_argv in main.cc.
for (int i = 1; i < argc; ++i)
{
// Adding/removing these options should not result in a full relink.
if (strcmp(argv[i], "--incremental") == 0
|| strcmp(argv[i], "--incremental-full") == 0
|| strcmp(argv[i], "--incremental-update") == 0
|| strcmp(argv[i], "--incremental-changed") == 0
|| strcmp(argv[i], "--incremental-unchanged") == 0
|| strcmp(argv[i], "--incremental-unknown") == 0)
continue;
args.append(" '");
// Now append argv[i], but with all single-quotes escaped
const char* argpos = argv[i];
while (1)
{
const int len = strcspn(argpos, "'");
args.append(argpos, len);
if (argpos[len] == '\0')
break;
args.append("'\"'\"'");
argpos += len + 1;
}
args.append("'");
}
this->command_line_ = args;
this->strtab_->add(this->command_line_.c_str(), false,
&this->command_line_key_);
}
// Record the input archive file ARCHIVE. This is called by the
// Add_archive_symbols task before determining which archive members
// to include. We create the Incremental_archive_entry here and
// attach it to the Archive, but we do not add it to the list of
// input objects until report_archive_end is called.
void
Incremental_inputs::report_archive_begin(Archive* arch)
{
Stringpool::Key filename_key;
Timespec mtime = arch->file().get_mtime();
this->strtab_->add(arch->filename().c_str(), false, &filename_key);
Incremental_archive_entry* entry =
new Incremental_archive_entry(filename_key, arch, mtime);
arch->set_incremental_info(entry);
}
// Finish recording the input archive file ARCHIVE. This is called by the
// Add_archive_symbols task after determining which archive members
// to include.
void
Incremental_inputs::report_archive_end(Archive* arch)
{
Incremental_archive_entry* entry = arch->incremental_info();
gold_assert(entry != NULL);
// Collect unused global symbols.
for (Archive::Unused_symbol_iterator p = arch->unused_symbols_begin();
p != arch->unused_symbols_end();
++p)
{
Stringpool::Key symbol_key;
this->strtab_->add(*p, true, &symbol_key);
entry->add_unused_global_symbol(symbol_key);
}
this->inputs_.push_back(entry);
}
// Record the input object file OBJ. If ARCH is not NULL, attach
// the object file to the archive. This is called by the
// Add_symbols task after finding out the type of the file.
void
Incremental_inputs::report_object(Object* obj, Archive* arch)
{
Stringpool::Key filename_key;
Timespec mtime = obj->input_file()->file().get_mtime();
this->strtab_->add(obj->name().c_str(), false, &filename_key);
Incremental_object_entry* obj_entry =
new Incremental_object_entry(filename_key, obj, mtime);
this->inputs_.push_back(obj_entry);
if (arch != NULL)
{
Incremental_archive_entry* arch_entry = arch->incremental_info();
gold_assert(arch_entry != NULL);
arch_entry->add_object(obj_entry);
}
this->current_object_ = obj;
this->current_object_entry_ = obj_entry;
}
// Record the input object file OBJ. If ARCH is not NULL, attach
// the object file to the archive. This is called by the
// Add_symbols task after finding out the type of the file.
void
Incremental_inputs::report_input_section(Object* obj, unsigned int shndx,
const char* name, off_t sh_size)
{
Stringpool::Key key = 0;
if (name != NULL)
this->strtab_->add(name, true, &key);
gold_assert(obj == this->current_object_);
this->current_object_entry_->add_input_section(shndx, key, sh_size);
}
// Record that the input argument INPUT is a script SCRIPT. This is
// called by read_script after parsing the script and reading the list
// of inputs added by this script.
void
Incremental_inputs::report_script(const std::string& filename,
Script_info* script, Timespec mtime)
{
Stringpool::Key filename_key;
this->strtab_->add(filename.c_str(), false, &filename_key);
Incremental_script_entry* entry =
new Incremental_script_entry(filename_key, script, mtime);
this->inputs_.push_back(entry);
}
// Finalize the incremental link information. Called from
// Layout::finalize.
void
Incremental_inputs::finalize()
{
// Finalize the string table.
this->strtab_->set_string_offsets();
}
// Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
void
Incremental_inputs::create_data_sections(Symbol_table* symtab)
{
switch (parameters->size_and_endianness())
{
#ifdef HAVE_TARGET_32_LITTLE
case Parameters::TARGET_32_LITTLE:
this->inputs_section_ =
new Output_section_incremental_inputs<32, false>(this, symtab);
break;
#endif
#ifdef HAVE_TARGET_32_BIG
case Parameters::TARGET_32_BIG:
this->inputs_section_ =
new Output_section_incremental_inputs<32, true>(this, symtab);
break;
#endif
#ifdef HAVE_TARGET_64_LITTLE
case Parameters::TARGET_64_LITTLE:
this->inputs_section_ =
new Output_section_incremental_inputs<64, false>(this, symtab);
break;
#endif
#ifdef HAVE_TARGET_64_BIG
case Parameters::TARGET_64_BIG:
this->inputs_section_ =
new Output_section_incremental_inputs<64, true>(this, symtab);
break;
#endif
default:
gold_unreachable();
}
this->symtab_section_ = new Output_data_space(4, "** incremental_symtab");
this->relocs_section_ = new Output_data_space(4, "** incremental_relocs");
this->got_plt_section_ = new Output_data_space(4, "** incremental_got_plt");
}
// Return the sh_entsize value for the .gnu_incremental_relocs section.
unsigned int
Incremental_inputs::relocs_entsize() const
{
return 8 + 2 * parameters->target().get_size() / 8;
}
// Class Output_section_incremental_inputs.
// Finalize the offsets for each input section and supplemental info block,
// and set the final data size of the incremental output sections.
template<int size, bool big_endian>
void
Output_section_incremental_inputs<size, big_endian>::set_final_data_size()
{
const Incremental_inputs* inputs = this->inputs_;
const unsigned int sizeof_addr = size / 8;
const unsigned int rel_size = 8 + 2 * sizeof_addr;
// Offset of each input entry.
unsigned int input_offset = this->header_size;
// Offset of each supplemental info block.
unsigned int info_offset = this->header_size;
info_offset += this->input_entry_size * inputs->input_file_count();
// Count each input file and its supplemental information block.
for (Incremental_inputs::Input_list::const_iterator p =
inputs->input_files().begin();
p != inputs->input_files().end();
++p)
{
// Set the offset of the input file entry.
(*p)->set_offset(input_offset);
input_offset += this->input_entry_size;
// Set the offset of the supplemental info block.
switch ((*p)->type())
{
case INCREMENTAL_INPUT_SCRIPT:
// No supplemental info for a script.
(*p)->set_info_offset(0);
break;
case INCREMENTAL_INPUT_OBJECT:
case INCREMENTAL_INPUT_ARCHIVE_MEMBER:
{
Incremental_object_entry* entry = (*p)->object_entry();
gold_assert(entry != NULL);
(*p)->set_info_offset(info_offset);
// Input section count + global symbol count.
info_offset += 8;
// Each input section.
info_offset += (entry->get_input_section_count()
* (8 + 2 * sizeof_addr));
// Each global symbol.
const Object::Symbols* syms = entry->object()->get_global_symbols();
info_offset += syms->size() * 16;
}
break;
case INCREMENTAL_INPUT_SHARED_LIBRARY:
{
Incremental_object_entry* entry = (*p)->object_entry();
gold_assert(entry != NULL);
(*p)->set_info_offset(info_offset);
// Global symbol count.
info_offset += 4;
// Each global symbol.
const Object::Symbols* syms = entry->object()->get_global_symbols();
unsigned int nsyms = syms != NULL ? syms->size() : 0;
info_offset += nsyms * 4;
}
break;
case INCREMENTAL_INPUT_ARCHIVE:
{
Incremental_archive_entry* entry = (*p)->archive_entry();
gold_assert(entry != NULL);
(*p)->set_info_offset(info_offset);
// Member count + unused global symbol count.
info_offset += 8;
// Each member.
info_offset += (entry->get_member_count() * 4);
// Each global symbol.
info_offset += (entry->get_unused_global_symbol_count() * 4);
}
break;
default:
gold_unreachable();
}
}
this->set_data_size(info_offset);
// Set the size of the .gnu_incremental_symtab section.
inputs->symtab_section()->set_current_data_size(this->symtab_->output_count()
* sizeof(unsigned int));
// Set the size of the .gnu_incremental_relocs section.
inputs->relocs_section()->set_current_data_size(inputs->get_reloc_count()
* rel_size);
// Set the size of the .gnu_incremental_got_plt section.
Sized_target<size, big_endian>* target =
parameters->sized_target<size, big_endian>();
unsigned int got_count = target->got_entry_count();
unsigned int plt_count = target->plt_entry_count();
unsigned int got_plt_size = 8; // GOT entry count, PLT entry count.
got_plt_size = (got_plt_size + got_count + 3) & ~3; // GOT type array.
got_plt_size += got_count * 4 + plt_count * 4; // GOT array, PLT array.
inputs->got_plt_section()->set_current_data_size(got_plt_size);
}
// Write the contents of the .gnu_incremental_inputs and
// .gnu_incremental_symtab sections.
template<int size, bool big_endian>
void
Output_section_incremental_inputs<size, big_endian>::do_write(Output_file* of)
{
const Incremental_inputs* inputs = this->inputs_;
Stringpool* strtab = inputs->get_stringpool();
// Get a view into the .gnu_incremental_inputs section.
const off_t off = this->offset();
const off_t oview_size = this->data_size();
unsigned char* const oview = of->get_output_view(off, oview_size);
unsigned char* pov = oview;
// Get a view into the .gnu_incremental_symtab section.
const off_t symtab_off = inputs->symtab_section()->offset();
const off_t symtab_size = inputs->symtab_section()->data_size();
unsigned char* const symtab_view = of->get_output_view(symtab_off,
symtab_size);
// Allocate an array of linked list heads for the .gnu_incremental_symtab
// section. Each element corresponds to a global symbol in the output
// symbol table, and points to the head of the linked list that threads
// through the object file input entries. The value of each element
// is the section-relative offset to a global symbol entry in a
// supplemental information block.
unsigned int global_sym_count = this->symtab_->output_count();
unsigned int* global_syms = new unsigned int[global_sym_count];
memset(global_syms, 0, global_sym_count * sizeof(unsigned int));
// Write the section header.
Stringpool::Key command_line_key = inputs->command_line_key();
pov = this->write_header(pov, inputs->input_file_count(),
strtab->get_offset_from_key(command_line_key));
// Write the list of input files.
pov = this->write_input_files(oview, pov, strtab);
// Write the supplemental information blocks for each input file.
pov = this->write_info_blocks(oview, pov, strtab, global_syms,
global_sym_count);
gold_assert(pov - oview == oview_size);
// Write the .gnu_incremental_symtab section.
gold_assert(global_sym_count * 4 == symtab_size);
this->write_symtab(symtab_view, global_syms, global_sym_count);
delete[] global_syms;
// Write the .gnu_incremental_got_plt section.
const off_t got_plt_off = inputs->got_plt_section()->offset();
const off_t got_plt_size = inputs->got_plt_section()->data_size();
unsigned char* const got_plt_view = of->get_output_view(got_plt_off,
got_plt_size);
this->write_got_plt(got_plt_view, got_plt_size);
of->write_output_view(off, oview_size, oview);
of->write_output_view(symtab_off, symtab_size, symtab_view);
of->write_output_view(got_plt_off, got_plt_size, got_plt_view);
}
// Write the section header: version, input file count, offset of command line
// in the string table, and 4 bytes of padding.
template<int size, bool big_endian>
unsigned char*
Output_section_incremental_inputs<size, big_endian>::write_header(
unsigned char* pov,
unsigned int input_file_count,
section_offset_type command_line_offset)
{
Swap32::writeval(pov, INCREMENTAL_LINK_VERSION);
Swap32::writeval(pov + 4, input_file_count);
Swap32::writeval(pov + 8, command_line_offset);
Swap32::writeval(pov + 12, 0);
return pov + this->header_size;
}
// Write the input file entries.
template<int size, bool big_endian>
unsigned char*
Output_section_incremental_inputs<size, big_endian>::write_input_files(
unsigned char* oview,
unsigned char* pov,
Stringpool* strtab)
{
const Incremental_inputs* inputs = this->inputs_;
for (Incremental_inputs::Input_list::const_iterator p =
inputs->input_files().begin();
p != inputs->input_files().end();
++p)
{
gold_assert(static_cast<unsigned int>(pov - oview) == (*p)->get_offset());
section_offset_type filename_offset =
strtab->get_offset_from_key((*p)->get_filename_key());
const Timespec& mtime = (*p)->get_mtime();
Swap32::writeval(pov, filename_offset);
Swap32::writeval(pov + 4, (*p)->get_info_offset());
Swap64::writeval(pov + 8, mtime.seconds);
Swap32::writeval(pov + 16, mtime.nanoseconds);
Swap16::writeval(pov + 20, (*p)->type());
Swap16::writeval(pov + 22, 0);
pov += this->input_entry_size;
}
return pov;
}
// Write the supplemental information blocks.
template<int size, bool big_endian>
unsigned char*
Output_section_incremental_inputs<size, big_endian>::write_info_blocks(
unsigned char* oview,
unsigned char* pov,
Stringpool* strtab,
unsigned int* global_syms,
unsigned int global_sym_count)
{
const Incremental_inputs* inputs = this->inputs_;
unsigned int first_global_index = this->symtab_->first_global_index();
for (Incremental_inputs::Input_list::const_iterator p =
inputs->input_files().begin();
p != inputs->input_files().end();
++p)
{
switch ((*p)->type())
{
case INCREMENTAL_INPUT_SCRIPT:
// No supplemental info for a script.
break;
case INCREMENTAL_INPUT_OBJECT:
case INCREMENTAL_INPUT_ARCHIVE_MEMBER:
{
gold_assert(static_cast<unsigned int>(pov - oview)
== (*p)->get_info_offset());
Incremental_object_entry* entry = (*p)->object_entry();
gold_assert(entry != NULL);
const Object* obj = entry->object();
const Object::Symbols* syms = obj->get_global_symbols();
// Write the input section count and global symbol count.
unsigned int nsections = entry->get_input_section_count();
unsigned int nsyms = syms->size();
Swap32::writeval(pov, nsections);
Swap32::writeval(pov + 4, nsyms);
pov += 8;
// For each input section, write the name, output section index,
// offset within output section, and input section size.
for (unsigned int i = 0; i < nsections; i++)
{
Stringpool::Key key = entry->get_input_section_name_key(i);
off_t name_offset = 0;
if (key != 0)
name_offset = strtab->get_offset_from_key(key);
int out_shndx = 0;
off_t out_offset = 0;
off_t sh_size = 0;
Output_section* os = obj->output_section(i);
if (os != NULL)
{
out_shndx = os->out_shndx();
out_offset = obj->output_section_offset(i);
sh_size = entry->get_input_section_size(i);
}
Swap32::writeval(pov, name_offset);
Swap32::writeval(pov + 4, out_shndx);
Swap::writeval(pov + 8, out_offset);
Swap::writeval(pov + 8 + sizeof_addr, sh_size);
pov += 8 + 2 * sizeof_addr;
}
// For each global symbol, write its associated relocations,
// add it to the linked list of globals, then write the
// supplemental information: global symbol table index,
// linked list chain pointer, relocation count, and offset
// to the relocations.
for (unsigned int i = 0; i < nsyms; i++)
{
const Symbol* sym = (*syms)[i];
if (sym->is_forwarder())
sym = this->symtab_->resolve_forwards(sym);
unsigned int symtab_index = sym->symtab_index();
unsigned int chain = 0;
unsigned int first_reloc = 0;
unsigned int nrelocs = obj->get_incremental_reloc_count(i);
if (nrelocs > 0)
{
gold_assert(symtab_index != -1U
&& (symtab_index - first_global_index
< global_sym_count));
first_reloc = obj->get_incremental_reloc_base(i);
chain = global_syms[symtab_index - first_global_index];
global_syms[symtab_index - first_global_index] =
pov - oview;
}
Swap32::writeval(pov, symtab_index);
Swap32::writeval(pov + 4, chain);
Swap32::writeval(pov + 8, nrelocs);
Swap32::writeval(pov + 12, first_reloc * 3 * sizeof_addr);
pov += 16;
}
}
break;
case INCREMENTAL_INPUT_SHARED_LIBRARY:
{
gold_assert(static_cast<unsigned int>(pov - oview)
== (*p)->get_info_offset());
Incremental_object_entry* entry = (*p)->object_entry();
gold_assert(entry != NULL);
const Object* obj = entry->object();
const Object::Symbols* syms = obj->get_global_symbols();
// Write the global symbol count.
unsigned int nsyms = syms != NULL ? syms->size() : 0;
Swap32::writeval(pov, nsyms);
pov += 4;
// For each global symbol, write the global symbol table index.
for (unsigned int i = 0; i < nsyms; i++)
{
const Symbol* sym = (*syms)[i];
Swap32::writeval(pov, sym->symtab_index());
pov += 4;
}
}
break;
case INCREMENTAL_INPUT_ARCHIVE:
{
gold_assert(static_cast<unsigned int>(pov - oview)
== (*p)->get_info_offset());
Incremental_archive_entry* entry = (*p)->archive_entry();
gold_assert(entry != NULL);
// Write the member count and unused global symbol count.
unsigned int nmembers = entry->get_member_count();
unsigned int nsyms = entry->get_unused_global_symbol_count();
Swap32::writeval(pov, nmembers);
Swap32::writeval(pov + 4, nsyms);
pov += 8;
// For each member, write the offset to its input file entry.
for (unsigned int i = 0; i < nmembers; ++i)
{
Incremental_object_entry* member = entry->get_member(i);
Swap32::writeval(pov, member->get_offset());
pov += 4;
}
// For each global symbol, write the name offset.
for (unsigned int i = 0; i < nsyms; ++i)
{
Stringpool::Key key = entry->get_unused_global_symbol(i);
Swap32::writeval(pov, strtab->get_offset_from_key(key));
pov += 4;
}
}
break;
default:
gold_unreachable();
}
}
return pov;
}
// Write the contents of the .gnu_incremental_symtab section.
template<int size, bool big_endian>
void
Output_section_incremental_inputs<size, big_endian>::write_symtab(
unsigned char* pov,
unsigned int* global_syms,
unsigned int global_sym_count)
{
for (unsigned int i = 0; i < global_sym_count; ++i)
{
Swap32::writeval(pov, global_syms[i]);
pov += 4;
}
}
// This struct holds the view information needed to write the
// .gnu_incremental_got_plt section.
struct Got_plt_view_info
{
// Start of the GOT type array in the output view.
unsigned char* got_type_p;
// Start of the GOT descriptor array in the output view.
unsigned char* got_desc_p;
// Start of the PLT descriptor array in the output view.
unsigned char* plt_desc_p;
// Number of GOT entries.
unsigned int got_count;
// Number of PLT entries.
unsigned int plt_count;
// Offset of the first non-reserved PLT entry (this is a target-dependent value).
unsigned int first_plt_entry_offset;
// Size of a PLT entry (this is a target-dependent value).
unsigned int plt_entry_size;
// Value to write in the GOT descriptor array. For global symbols,
// this is the global symbol table index; for local symbols, it is
// the offset of the input file entry in the .gnu_incremental_inputs
// section.
unsigned int got_descriptor;
};
// Functor class for processing a GOT offset list for local symbols.
// Writes the GOT type and symbol index into the GOT type and descriptor
// arrays in the output section.
template<int size, bool big_endian>
class Local_got_offset_visitor
{
public:
Local_got_offset_visitor(struct Got_plt_view_info& info)
: info_(info)
{ }
void
operator()(unsigned int got_type, unsigned int got_offset)
{
unsigned int got_index = got_offset / this->got_entry_size_;
gold_assert(got_index < this->info_.got_count);
// We can only handle GOT entry types in the range 0..0x7e
// because we use a byte array to store them, and we use the
// high bit to flag a local symbol.
gold_assert(got_type < 0x7f);
this->info_.got_type_p[got_index] = got_type | 0x80;
unsigned char* pov = this->info_.got_desc_p + got_index * 4;
elfcpp::Swap<32, big_endian>::writeval(pov, this->info_.got_descriptor);
}
private:
static const unsigned int got_entry_size_ = size / 8;
struct Got_plt_view_info& info_;
};
// Functor class for processing a GOT offset list. Writes the GOT type
// and symbol index into the GOT type and descriptor arrays in the output
// section.
template<int size, bool big_endian>
class Global_got_offset_visitor
{
public:
Global_got_offset_visitor(struct Got_plt_view_info& info)
: info_(info)
{ }
void
operator()(unsigned int got_type, unsigned int got_offset)
{
unsigned int got_index = got_offset / this->got_entry_size_;
gold_assert(got_index < this->info_.got_count);
// We can only handle GOT entry types in the range 0..0x7e
// because we use a byte array to store them, and we use the
// high bit to flag a local symbol.
gold_assert(got_type < 0x7f);
this->info_.got_type_p[got_index] = got_type;
unsigned char* pov = this->info_.got_desc_p + got_index * 4;
elfcpp::Swap<32, big_endian>::writeval(pov, this->info_.got_descriptor);
}
private:
static const unsigned int got_entry_size_ = size / 8;
struct Got_plt_view_info& info_;
};
// Functor class for processing the global symbol table. Processes the
// GOT offset list for the symbol, and writes the symbol table index
// into the PLT descriptor array in the output section.
template<int size, bool big_endian>
class Global_symbol_visitor_got_plt
{
public:
Global_symbol_visitor_got_plt(struct Got_plt_view_info& info)
: info_(info)
{ }
void
operator()(const Sized_symbol<size>* sym)
{
typedef Global_got_offset_visitor<size, big_endian> Got_visitor;
const Got_offset_list* got_offsets = sym->got_offset_list();
if (got_offsets != NULL)
{
info_.got_descriptor = sym->symtab_index();
got_offsets->for_all_got_offsets(Got_visitor(info_));
}
if (sym->has_plt_offset())
{
unsigned int plt_index =
((sym->plt_offset() - this->info_.first_plt_entry_offset)
/ this->info_.plt_entry_size);
gold_assert(plt_index < this->info_.plt_count);
unsigned char* pov = this->info_.plt_desc_p + plt_index * 4;
elfcpp::Swap<32, big_endian>::writeval(pov, sym->symtab_index());
}
}
private:
struct Got_plt_view_info& info_;
};
// Write the contents of the .gnu_incremental_got_plt section.
template<int size, bool big_endian>
void
Output_section_incremental_inputs<size, big_endian>::write_got_plt(
unsigned char* pov,
off_t view_size)
{
Sized_target<size, big_endian>* target =
parameters->sized_target<size, big_endian>();
// Set up the view information for the functors.
struct Got_plt_view_info view_info;
view_info.got_count = target->got_entry_count();
view_info.plt_count = target->plt_entry_count();
view_info.first_plt_entry_offset = target->first_plt_entry_offset();
view_info.plt_entry_size = target->plt_entry_size();
view_info.got_type_p = pov + 8;
view_info.got_desc_p = (view_info.got_type_p
+ ((view_info.got_count + 3) & ~3));
view_info.plt_desc_p = view_info.got_desc_p + view_info.got_count * 4;
gold_assert(pov + view_size ==
view_info.plt_desc_p + view_info.plt_count * 4);
// Write the section header.
Swap32::writeval(pov, view_info.got_count);
Swap32::writeval(pov + 4, view_info.plt_count);
// Initialize the GOT type array to 0xff (reserved).
memset(view_info.got_type_p, 0xff, view_info.got_count);
// Write the incremental GOT descriptors for local symbols.
for (Incremental_inputs::Input_list::const_iterator p =
this->inputs_->input_files().begin();
p != this->inputs_->input_files().end();
++p)
{
if ((*p)->type() != INCREMENTAL_INPUT_OBJECT
&& (*p)->type() != INCREMENTAL_INPUT_ARCHIVE_MEMBER)
continue;
Incremental_object_entry* entry = (*p)->object_entry();
gold_assert(entry != NULL);
const Sized_relobj<size, big_endian>* obj =
static_cast<Sized_relobj<size, big_endian>*>(entry->object());
gold_assert(obj != NULL);
unsigned int nsyms = obj->local_symbol_count();
for (unsigned int i = 0; i < nsyms; i++)
{
const Got_offset_list* got_offsets = obj->local_got_offset_list(i);
if (got_offsets != NULL)
{
typedef Local_got_offset_visitor<size, big_endian> Got_visitor;
view_info.got_descriptor = (*p)->get_offset();
got_offsets->for_all_got_offsets(Got_visitor(view_info));
}
}
}
// Write the incremental GOT and PLT descriptors for global symbols.
typedef Global_symbol_visitor_got_plt<size, big_endian> Symbol_visitor;
symtab_->for_all_symbols<size, Symbol_visitor>(Symbol_visitor(view_info));
}
// Instantiate the templates we need.
#ifdef HAVE_TARGET_32_LITTLE
template
class Sized_incremental_binary<32, false>;
#endif
#ifdef HAVE_TARGET_32_BIG
template
class Sized_incremental_binary<32, true>;
#endif
#ifdef HAVE_TARGET_64_LITTLE
template
class Sized_incremental_binary<64, false>;
#endif
#ifdef HAVE_TARGET_64_BIG
template
class Sized_incremental_binary<64, true>;
#endif
} // End namespace gold.
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