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binutils-gdb/gold/output.h

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// output.h -- manage the output file for gold -*- C++ -*-
// Copyright 2006, 2007, 2008, 2009, 2010, 2011 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.
#ifndef GOLD_OUTPUT_H
#define GOLD_OUTPUT_H
#include <list>
#include <vector>
#include "elfcpp.h"
#include "mapfile.h"
#include "layout.h"
#include "reloc-types.h"
namespace gold
{
class General_options;
class Object;
class Symbol;
class Output_file;
class Output_merge_base;
class Output_section;
class Relocatable_relocs;
class Target;
template<int size, bool big_endian>
class Sized_target;
template<int size, bool big_endian>
class Sized_relobj;
template<int size, bool big_endian>
class Sized_relobj_file;
// An abtract class for data which has to go into the output file.
class Output_data
{
public:
explicit Output_data()
: address_(0), data_size_(0), offset_(-1),
is_address_valid_(false), is_data_size_valid_(false),
is_offset_valid_(false), is_data_size_fixed_(false),
has_dynamic_reloc_(false)
{ }
virtual
~Output_data();
// Return the address. For allocated sections, this is only valid
// after Layout::finalize is finished.
uint64_t
address() const
{
gold_assert(this->is_address_valid_);
return this->address_;
}
// Return the size of the data. For allocated sections, this must
// be valid after Layout::finalize calls set_address, but need not
// be valid before then.
off_t
data_size() const
{
gold_assert(this->is_data_size_valid_);
return this->data_size_;
}
// Get the current data size.
off_t
current_data_size() const
{ return this->current_data_size_for_child(); }
// Return true if data size is fixed.
bool
is_data_size_fixed() const
{ return this->is_data_size_fixed_; }
// Return the file offset. This is only valid after
// Layout::finalize is finished. For some non-allocated sections,
// it may not be valid until near the end of the link.
off_t
offset() const
{
gold_assert(this->is_offset_valid_);
return this->offset_;
}
// Reset the address, file offset and data size. This essentially
// disables the sanity testing about duplicate and unknown settings.
void
reset_address_and_file_offset()
{
this->is_address_valid_ = false;
this->is_offset_valid_ = false;
if (!this->is_data_size_fixed_)
this->is_data_size_valid_ = false;
this->do_reset_address_and_file_offset();
}
// As above, but just for data size.
void
reset_data_size()
{
if (!this->is_data_size_fixed_)
this->is_data_size_valid_ = false;
}
// Return true if address and file offset already have reset values. In
// other words, calling reset_address_and_file_offset will not change them.
bool
address_and_file_offset_have_reset_values() const
{ return this->do_address_and_file_offset_have_reset_values(); }
// Return the required alignment.
uint64_t
addralign() const
{ return this->do_addralign(); }
// Return whether this has a load address.
bool
has_load_address() const
{ return this->do_has_load_address(); }
// Return the load address.
uint64_t
load_address() const
{ return this->do_load_address(); }
// Return whether this is an Output_section.
bool
is_section() const
{ return this->do_is_section(); }
// Return whether this is an Output_section of the specified type.
bool
is_section_type(elfcpp::Elf_Word stt) const
{ return this->do_is_section_type(stt); }
// Return whether this is an Output_section with the specified flag
// set.
bool
is_section_flag_set(elfcpp::Elf_Xword shf) const
{ return this->do_is_section_flag_set(shf); }
// Return the output section that this goes in, if there is one.
Output_section*
output_section()
{ return this->do_output_section(); }
const Output_section*
output_section() const
{ return this->do_output_section(); }
// Return the output section index, if there is an output section.
unsigned int
out_shndx() const
{ return this->do_out_shndx(); }
// Set the output section index, if this is an output section.
void
set_out_shndx(unsigned int shndx)
{ this->do_set_out_shndx(shndx); }
// Set the address and file offset of this data, and finalize the
// size of the data. This is called during Layout::finalize for
// allocated sections.
void
set_address_and_file_offset(uint64_t addr, off_t off)
{
this->set_address(addr);
this->set_file_offset(off);
this->finalize_data_size();
}
// Set the address.
void
set_address(uint64_t addr)
{
gold_assert(!this->is_address_valid_);
this->address_ = addr;
this->is_address_valid_ = true;
}
// Set the file offset.
void
set_file_offset(off_t off)
{
gold_assert(!this->is_offset_valid_);
this->offset_ = off;
this->is_offset_valid_ = true;
}
// Update the data size without finalizing it.
void
pre_finalize_data_size()
{
if (!this->is_data_size_valid_)
{
// Tell the child class to update the data size.
this->update_data_size();
}
}
// Finalize the data size.
void
finalize_data_size()
{
if (!this->is_data_size_valid_)
{
// Tell the child class to set the data size.
this->set_final_data_size();
gold_assert(this->is_data_size_valid_);
}
}
// Set the TLS offset. Called only for SHT_TLS sections.
void
set_tls_offset(uint64_t tls_base)
{ this->do_set_tls_offset(tls_base); }
// Return the TLS offset, relative to the base of the TLS segment.
// Valid only for SHT_TLS sections.
uint64_t
tls_offset() const
{ return this->do_tls_offset(); }
// Write the data to the output file. This is called after
// Layout::finalize is complete.
void
write(Output_file* file)
{ this->do_write(file); }
// This is called by Layout::finalize to note that the sizes of
// allocated sections must now be fixed.
static void
layout_complete()
{ Output_data::allocated_sizes_are_fixed = true; }
// Used to check that layout has been done.
static bool
is_layout_complete()
{ return Output_data::allocated_sizes_are_fixed; }
// Note that a dynamic reloc has been applied to this data.
void
add_dynamic_reloc()
{ this->has_dynamic_reloc_ = true; }
// Return whether a dynamic reloc has been applied.
bool
has_dynamic_reloc() const
{ return this->has_dynamic_reloc_; }
// Whether the address is valid.
bool
is_address_valid() const
{ return this->is_address_valid_; }
// Whether the file offset is valid.
bool
is_offset_valid() const
{ return this->is_offset_valid_; }
// Whether the data size is valid.
bool
is_data_size_valid() const
{ return this->is_data_size_valid_; }
// Print information to the map file.
void
print_to_mapfile(Mapfile* mapfile) const
{ return this->do_print_to_mapfile(mapfile); }
protected:
// Functions that child classes may or in some cases must implement.
// Write the data to the output file.
virtual void
do_write(Output_file*) = 0;
// Return the required alignment.
virtual uint64_t
do_addralign() const = 0;
// Return whether this has a load address.
virtual bool
do_has_load_address() const
{ return false; }
// Return the load address.
virtual uint64_t
do_load_address() const
{ gold_unreachable(); }
// Return whether this is an Output_section.
virtual bool
do_is_section() const
{ return false; }
// Return whether this is an Output_section of the specified type.
// This only needs to be implement by Output_section.
virtual bool
do_is_section_type(elfcpp::Elf_Word) const
{ return false; }
// Return whether this is an Output_section with the specific flag
// set. This only needs to be implemented by Output_section.
virtual bool
do_is_section_flag_set(elfcpp::Elf_Xword) const
{ return false; }
// Return the output section, if there is one.
virtual Output_section*
do_output_section()
{ return NULL; }
virtual const Output_section*
do_output_section() const
{ return NULL; }
// Return the output section index, if there is an output section.
virtual unsigned int
do_out_shndx() const
{ gold_unreachable(); }
// Set the output section index, if this is an output section.
virtual void
do_set_out_shndx(unsigned int)
{ gold_unreachable(); }
// This is a hook for derived classes to set the preliminary data size.
// This is called by pre_finalize_data_size, normally called during
// Layout::finalize, before the section address is set, and is used
// during an incremental update, when we need to know the size of a
// section before allocating space in the output file. For classes
// where the current data size is up to date, this default version of
// the method can be inherited.
virtual void
update_data_size()
{ }
// This is a hook for derived classes to set the data size. This is
// called by finalize_data_size, normally called during
// Layout::finalize, when the section address is set.
virtual void
set_final_data_size()
{ gold_unreachable(); }
// A hook for resetting the address and file offset.
virtual void
do_reset_address_and_file_offset()
{ }
// Return true if address and file offset already have reset values. In
// other words, calling reset_address_and_file_offset will not change them.
// A child class overriding do_reset_address_and_file_offset may need to
// also override this.
virtual bool
do_address_and_file_offset_have_reset_values() const
{ return !this->is_address_valid_ && !this->is_offset_valid_; }
// Set the TLS offset. Called only for SHT_TLS sections.
virtual void
do_set_tls_offset(uint64_t)
{ gold_unreachable(); }
// Return the TLS offset, relative to the base of the TLS segment.
// Valid only for SHT_TLS sections.
virtual uint64_t
do_tls_offset() const
{ gold_unreachable(); }
// Print to the map file. This only needs to be implemented by
// classes which may appear in a PT_LOAD segment.
virtual void
do_print_to_mapfile(Mapfile*) const
{ gold_unreachable(); }
// Functions that child classes may call.
// Reset the address. The Output_section class needs this when an
// SHF_ALLOC input section is added to an output section which was
// formerly not SHF_ALLOC.
void
mark_address_invalid()
{ this->is_address_valid_ = false; }
// Set the size of the data.
void
set_data_size(off_t data_size)
{
gold_assert(!this->is_data_size_valid_
&& !this->is_data_size_fixed_);
this->data_size_ = data_size;
this->is_data_size_valid_ = true;
}
// Fix the data size. Once it is fixed, it cannot be changed
// and the data size remains always valid.
void
fix_data_size()
{
gold_assert(this->is_data_size_valid_);
this->is_data_size_fixed_ = true;
}
// Get the current data size--this is for the convenience of
// sections which build up their size over time.
off_t
current_data_size_for_child() const
{ return this->data_size_; }
// Set the current data size--this is for the convenience of
// sections which build up their size over time.
void
set_current_data_size_for_child(off_t data_size)
{
gold_assert(!this->is_data_size_valid_);
this->data_size_ = data_size;
}
// Return default alignment for the target size.
static uint64_t
default_alignment();
// Return default alignment for a specified size--32 or 64.
static uint64_t
default_alignment_for_size(int size);
private:
Output_data(const Output_data&);
Output_data& operator=(const Output_data&);
// This is used for verification, to make sure that we don't try to
// change any sizes of allocated sections after we set the section
// addresses.
static bool allocated_sizes_are_fixed;
// Memory address in output file.
uint64_t address_;
// Size of data in output file.
off_t data_size_;
// File offset of contents in output file.
off_t offset_;
// Whether address_ is valid.
bool is_address_valid_ : 1;
// Whether data_size_ is valid.
bool is_data_size_valid_ : 1;
// Whether offset_ is valid.
bool is_offset_valid_ : 1;
// Whether data size is fixed.
bool is_data_size_fixed_ : 1;
// Whether any dynamic relocs have been applied to this section.
bool has_dynamic_reloc_ : 1;
};
// Output the section headers.
class Output_section_headers : public Output_data
{
public:
Output_section_headers(const Layout*,
const Layout::Segment_list*,
const Layout::Section_list*,
const Layout::Section_list*,
const Stringpool*,
const Output_section*);
protected:
// Write the data to the file.
void
do_write(Output_file*);
// Return the required alignment.
uint64_t
do_addralign() const
{ return Output_data::default_alignment(); }
// Write to a map file.
void
do_print_to_mapfile(Mapfile* mapfile) const
{ mapfile->print_output_data(this, _("** section headers")); }
// Update the data size.
void
update_data_size()
{ this->set_data_size(this->do_size()); }
// Set final data size.
void
set_final_data_size()
{ this->set_data_size(this->do_size()); }
private:
// Write the data to the file with the right size and endianness.
template<int size, bool big_endian>
void
do_sized_write(Output_file*);
// Compute data size.
off_t
do_size() const;
const Layout* layout_;
const Layout::Segment_list* segment_list_;
const Layout::Section_list* section_list_;
const Layout::Section_list* unattached_section_list_;
const Stringpool* secnamepool_;
const Output_section* shstrtab_section_;
};
// Output the segment headers.
class Output_segment_headers : public Output_data
{
public:
Output_segment_headers(const Layout::Segment_list& segment_list);
protected:
// Write the data to the file.
void
do_write(Output_file*);
// Return the required alignment.
uint64_t
do_addralign() const
{ return Output_data::default_alignment(); }
// Write to a map file.
void
do_print_to_mapfile(Mapfile* mapfile) const
{ mapfile->print_output_data(this, _("** segment headers")); }
// Set final data size.
void
set_final_data_size()
{ this->set_data_size(this->do_size()); }
private:
// Write the data to the file with the right size and endianness.
template<int size, bool big_endian>
void
do_sized_write(Output_file*);
// Compute the current size.
off_t
do_size() const;
const Layout::Segment_list& segment_list_;
};
// Output the ELF file header.
class Output_file_header : public Output_data
{
public:
Output_file_header(const Target*,
const Symbol_table*,
const Output_segment_headers*);
// Add information about the section headers. We lay out the ELF
// file header before we create the section headers.
void set_section_info(const Output_section_headers*,
const Output_section* shstrtab);
protected:
// Write the data to the file.
void
do_write(Output_file*);
// Return the required alignment.
uint64_t
do_addralign() const
{ return Output_data::default_alignment(); }
// Write to a map file.
void
do_print_to_mapfile(Mapfile* mapfile) const
{ mapfile->print_output_data(this, _("** file header")); }
// Set final data size.
void
set_final_data_size(void)
{ this->set_data_size(this->do_size()); }
private:
// Write the data to the file with the right size and endianness.
template<int size, bool big_endian>
void
do_sized_write(Output_file*);
// Return the value to use for the entry address.
template<int size>
typename elfcpp::Elf_types<size>::Elf_Addr
entry();
// Compute the current data size.
off_t
do_size() const;
const Target* target_;
const Symbol_table* symtab_;
const Output_segment_headers* segment_header_;
const Output_section_headers* section_header_;
const Output_section* shstrtab_;
};
// Output sections are mainly comprised of input sections. However,
// there are cases where we have data to write out which is not in an
// input section. Output_section_data is used in such cases. This is
// an abstract base class.
class Output_section_data : public Output_data
{
public:
Output_section_data(off_t data_size, uint64_t addralign,
bool is_data_size_fixed)
: Output_data(), output_section_(NULL), addralign_(addralign)
{
this->set_data_size(data_size);
if (is_data_size_fixed)
this->fix_data_size();
}
Output_section_data(uint64_t addralign)
: Output_data(), output_section_(NULL), addralign_(addralign)
{ }
// Return the output section.
Output_section*
output_section()
{ return this->output_section_; }
const Output_section*
output_section() const
{ return this->output_section_; }
// Record the output section.
void
set_output_section(Output_section* os);
// Add an input section, for SHF_MERGE sections. This returns true
// if the section was handled.
bool
add_input_section(Relobj* object, unsigned int shndx)
{ return this->do_add_input_section(object, shndx); }
// Given an input OBJECT, an input section index SHNDX within that
// object, and an OFFSET relative to the start of that input
// section, return whether or not the corresponding offset within
// the output section is known. If this function returns true, it
// sets *POUTPUT to the output offset. The value -1 indicates that
// this input offset is being discarded.
bool
output_offset(const Relobj* object, unsigned int shndx,
section_offset_type offset,
section_offset_type* poutput) const
{ return this->do_output_offset(object, shndx, offset, poutput); }
// Return whether this is the merge section for the input section
// SHNDX in OBJECT. This should return true when output_offset
// would return true for some values of OFFSET.
bool
is_merge_section_for(const Relobj* object, unsigned int shndx) const
{ return this->do_is_merge_section_for(object, shndx); }
// Write the contents to a buffer. This is used for sections which
// require postprocessing, such as compression.
void
write_to_buffer(unsigned char* buffer)
{ this->do_write_to_buffer(buffer); }
// Print merge stats to stderr. This should only be called for
// SHF_MERGE sections.
void
print_merge_stats(const char* section_name)
{ this->do_print_merge_stats(section_name); }
protected:
// The child class must implement do_write.
// The child class may implement specific adjustments to the output
// section.
virtual void
do_adjust_output_section(Output_section*)
{ }
// May be implemented by child class. Return true if the section
// was handled.
virtual bool
do_add_input_section(Relobj*, unsigned int)
{ gold_unreachable(); }
// The child class may implement output_offset.
virtual bool
do_output_offset(const Relobj*, unsigned int, section_offset_type,
section_offset_type*) const
{ return false; }
// The child class may implement is_merge_section_for.
virtual bool
do_is_merge_section_for(const Relobj*, unsigned int) const
{ return false; }
// The child class may implement write_to_buffer. Most child
// classes can not appear in a compressed section, and they do not
// implement this.
virtual void
do_write_to_buffer(unsigned char*)
{ gold_unreachable(); }
// Print merge statistics.
virtual void
do_print_merge_stats(const char*)
{ gold_unreachable(); }
// Return the required alignment.
uint64_t
do_addralign() const
{ return this->addralign_; }
// Return the output section.
Output_section*
do_output_section()
{ return this->output_section_; }
const Output_section*
do_output_section() const
{ return this->output_section_; }
// Return the section index of the output section.
unsigned int
do_out_shndx() const;
// Set the alignment.
void
set_addralign(uint64_t addralign);
private:
// The output section for this section.
Output_section* output_section_;
// The required alignment.
uint64_t addralign_;
};
// Some Output_section_data classes build up their data step by step,
// rather than all at once. This class provides an interface for
// them.
class Output_section_data_build : public Output_section_data
{
public:
Output_section_data_build(uint64_t addralign)
: Output_section_data(addralign)
{ }
Output_section_data_build(off_t data_size, uint64_t addralign)
: Output_section_data(data_size, addralign, false)
{ }
// Set the current data size.
void
set_current_data_size(off_t data_size)
{ this->set_current_data_size_for_child(data_size); }
protected:
// Set the final data size.
virtual void
set_final_data_size()
{ this->set_data_size(this->current_data_size_for_child()); }
};
// A simple case of Output_data in which we have constant data to
// output.
class Output_data_const : public Output_section_data
{
public:
Output_data_const(const std::string& data, uint64_t addralign)
: Output_section_data(data.size(), addralign, true), data_(data)
{ }
Output_data_const(const char* p, off_t len, uint64_t addralign)
: Output_section_data(len, addralign, true), data_(p, len)
{ }
Output_data_const(const unsigned char* p, off_t len, uint64_t addralign)
: Output_section_data(len, addralign, true),
data_(reinterpret_cast<const char*>(p), len)
{ }
protected:
// Write the data to the output file.
void
do_write(Output_file*);
// Write the data to a buffer.
void
do_write_to_buffer(unsigned char* buffer)
{ memcpy(buffer, this->data_.data(), this->data_.size()); }
// Write to a map file.
void
do_print_to_mapfile(Mapfile* mapfile) const
{ mapfile->print_output_data(this, _("** fill")); }
private:
std::string data_;
};
// Another version of Output_data with constant data, in which the
// buffer is allocated by the caller.
class Output_data_const_buffer : public Output_section_data
{
public:
Output_data_const_buffer(const unsigned char* p, off_t len,
uint64_t addralign, const char* map_name)
: Output_section_data(len, addralign, true),
p_(p), map_name_(map_name)
{ }
protected:
// Write the data the output file.
void
do_write(Output_file*);
// Write the data to a buffer.
void
do_write_to_buffer(unsigned char* buffer)
{ memcpy(buffer, this->p_, this->data_size()); }
// Write to a map file.
void
do_print_to_mapfile(Mapfile* mapfile) const
{ mapfile->print_output_data(this, _(this->map_name_)); }
private:
// The data to output.
const unsigned char* p_;
// Name to use in a map file. Maps are a rarely used feature, but
// the space usage is minor as aren't very many of these objects.
const char* map_name_;
};
// A place holder for a fixed amount of data written out via some
// other mechanism.
class Output_data_fixed_space : public Output_section_data
{
public:
Output_data_fixed_space(off_t data_size, uint64_t addralign,
const char* map_name)
: Output_section_data(data_size, addralign, true),
map_name_(map_name)
{ }
protected:
// Write out the data--the actual data must be written out
// elsewhere.
void
do_write(Output_file*)
{ }
// Write to a map file.
void
do_print_to_mapfile(Mapfile* mapfile) const
{ mapfile->print_output_data(this, _(this->map_name_)); }
private:
// Name to use in a map file. Maps are a rarely used feature, but
// the space usage is minor as aren't very many of these objects.
const char* map_name_;
};
// A place holder for variable sized data written out via some other
// mechanism.
class Output_data_space : public Output_section_data_build
{
public:
explicit Output_data_space(uint64_t addralign, const char* map_name)
: Output_section_data_build(addralign),
map_name_(map_name)
{ }
explicit Output_data_space(off_t data_size, uint64_t addralign,
const char* map_name)
: Output_section_data_build(data_size, addralign),
map_name_(map_name)
{ }
// Set the alignment.
void
set_space_alignment(uint64_t align)
{ this->set_addralign(align); }
protected:
// Write out the data--the actual data must be written out
// elsewhere.
void
do_write(Output_file*)
{ }
// Write to a map file.
void
do_print_to_mapfile(Mapfile* mapfile) const
{ mapfile->print_output_data(this, _(this->map_name_)); }
private:
// Name to use in a map file. Maps are a rarely used feature, but
// the space usage is minor as aren't very many of these objects.
const char* map_name_;
};
// Fill fixed space with zeroes. This is just like
// Output_data_fixed_space, except that the map name is known.
class Output_data_zero_fill : public Output_section_data
{
public:
Output_data_zero_fill(off_t data_size, uint64_t addralign)
: Output_section_data(data_size, addralign, true)
{ }
protected:
// There is no data to write out.
void
do_write(Output_file*)
{ }
// Write to a map file.
void
do_print_to_mapfile(Mapfile* mapfile) const
{ mapfile->print_output_data(this, "** zero fill"); }
};
// A string table which goes into an output section.
class Output_data_strtab : public Output_section_data
{
public:
Output_data_strtab(Stringpool* strtab)
: Output_section_data(1), strtab_(strtab)
{ }
protected:
// This is called to update the section size prior to assigning
// the address and file offset.
void
update_data_size()
{ this->set_final_data_size(); }
// This is called to set the address and file offset. Here we make
// sure that the Stringpool is finalized.
void
set_final_data_size();
// Write out the data.
void
do_write(Output_file*);
// Write the data to a buffer.
void
do_write_to_buffer(unsigned char* buffer)
{ this->strtab_->write_to_buffer(buffer, this->data_size()); }
// Write to a map file.
void
do_print_to_mapfile(Mapfile* mapfile) const
{ mapfile->print_output_data(this, _("** string table")); }
private:
Stringpool* strtab_;
};
// This POD class is used to represent a single reloc in the output
// file. This could be a private class within Output_data_reloc, but
// the templatization is complex enough that I broke it out into a
// separate class. The class is templatized on either elfcpp::SHT_REL
// or elfcpp::SHT_RELA, and also on whether this is a dynamic
// relocation or an ordinary relocation.
// A relocation can be against a global symbol, a local symbol, a
// local section symbol, an output section, or the undefined symbol at
// index 0. We represent the latter by using a NULL global symbol.
template<int sh_type, bool dynamic, int size, bool big_endian>
class Output_reloc;
template<bool dynamic, int size, bool big_endian>
class Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>
{
public:
typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
typedef typename elfcpp::Elf_types<size>::Elf_Addr Addend;
static const Address invalid_address = static_cast<Address>(0) - 1;
// An uninitialized entry. We need this because we want to put
// instances of this class into an STL container.
Output_reloc()
: local_sym_index_(INVALID_CODE)
{ }
// We have a bunch of different constructors. They come in pairs
// depending on how the address of the relocation is specified. It
// can either be an offset in an Output_data or an offset in an
// input section.
// A reloc against a global symbol.
Output_reloc(Symbol* gsym, unsigned int type, Output_data* od,
Address address, bool is_relative, bool is_symbolless,
bool use_plt_offset);
Output_reloc(Symbol* gsym, unsigned int type,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address, bool is_relative,
bool is_symbolless, bool use_plt_offset);
// A reloc against a local symbol or local section symbol.
Output_reloc(Sized_relobj<size, big_endian>* relobj,
unsigned int local_sym_index, unsigned int type,
Output_data* od, Address address, bool is_relative,
bool is_symbolless, bool is_section_symbol,
bool use_plt_offset);
Output_reloc(Sized_relobj<size, big_endian>* relobj,
unsigned int local_sym_index, unsigned int type,
unsigned int shndx, Address address, bool is_relative,
bool is_symbolless, bool is_section_symbol,
bool use_plt_offset);
// A reloc against the STT_SECTION symbol of an output section.
Output_reloc(Output_section* os, unsigned int type, Output_data* od,
Address address, bool is_relative);
Output_reloc(Output_section* os, unsigned int type,
Sized_relobj<size, big_endian>* relobj, unsigned int shndx,
Address address, bool is_relative);
// An absolute or relative relocation with no symbol.
Output_reloc(unsigned int type, Output_data* od, Address address,
bool is_relative);
Output_reloc(unsigned int type, Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address, bool is_relative);
// A target specific relocation. The target will be called to get
// the symbol index, passing ARG. The type and offset will be set
// as for other relocation types.
Output_reloc(unsigned int type, void* arg, Output_data* od,
Address address);
Output_reloc(unsigned int type, void* arg,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address);
// Return the reloc type.
unsigned int
type() const
{ return this->type_; }
// Return whether this is a RELATIVE relocation.
bool
is_relative() const
{ return this->is_relative_; }
// Return whether this is a relocation which should not use
// a symbol, but which obtains its addend from a symbol.
bool
is_symbolless() const
{ return this->is_symbolless_; }
// Return whether this is against a local section symbol.
bool
is_local_section_symbol() const
{
return (this->local_sym_index_ != GSYM_CODE
&& this->local_sym_index_ != SECTION_CODE
&& this->local_sym_index_ != INVALID_CODE
&& this->local_sym_index_ != TARGET_CODE
&& this->is_section_symbol_);
}
// Return whether this is a target specific relocation.
bool
is_target_specific() const
{ return this->local_sym_index_ == TARGET_CODE; }
// Return the argument to pass to the target for a target specific
// relocation.
void*
target_arg() const
{
gold_assert(this->local_sym_index_ == TARGET_CODE);
return this->u1_.arg;
}
// For a local section symbol, return the offset of the input
// section within the output section. ADDEND is the addend being
// applied to the input section.
Address
local_section_offset(Addend addend) const;
// Get the value of the symbol referred to by a Rel relocation when
// we are adding the given ADDEND.
Address
symbol_value(Addend addend) const;
// If this relocation is against an input section, return the
// relocatable object containing the input section.
Sized_relobj<size, big_endian>*
get_relobj() const
{
if (this->shndx_ == INVALID_CODE)
return NULL;
return this->u2_.relobj;
}
// Write the reloc entry to an output view.
void
write(unsigned char* pov) const;
// Write the offset and info fields to Write_rel.
template<typename Write_rel>
void write_rel(Write_rel*) const;
// This is used when sorting dynamic relocs. Return -1 to sort this
// reloc before R2, 0 to sort the same as R2, 1 to sort after R2.
int
compare(const Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>& r2)
const;
// Return whether this reloc should be sorted before the argument
// when sorting dynamic relocs.
bool
sort_before(const Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>&
r2) const
{ return this->compare(r2) < 0; }
private:
// Record that we need a dynamic symbol index.
void
set_needs_dynsym_index();
// Return the symbol index.
unsigned int
get_symbol_index() const;
// Return the output address.
Address
get_address() const;
// Codes for local_sym_index_.
enum
{
// Global symbol.
GSYM_CODE = -1U,
// Output section.
SECTION_CODE = -2U,
// Target specific.
TARGET_CODE = -3U,
// Invalid uninitialized entry.
INVALID_CODE = -4U
};
union
{
// For a local symbol or local section symbol
// (this->local_sym_index_ >= 0), the object. We will never
// generate a relocation against a local symbol in a dynamic
// object; that doesn't make sense. And our callers will always
// be templatized, so we use Sized_relobj here.
Sized_relobj<size, big_endian>* relobj;
// For a global symbol (this->local_sym_index_ == GSYM_CODE, the
// symbol. If this is NULL, it indicates a relocation against the
// undefined 0 symbol.
Symbol* gsym;
// For a relocation against an output section
// (this->local_sym_index_ == SECTION_CODE), the output section.
Output_section* os;
// For a target specific relocation, an argument to pass to the
// target.
void* arg;
} u1_;
union
{
// If this->shndx_ is not INVALID CODE, the object which holds the
// input section being used to specify the reloc address.
Sized_relobj<size, big_endian>* relobj;
// If this->shndx_ is INVALID_CODE, the output data being used to
// specify the reloc address. This may be NULL if the reloc
// address is absolute.
Output_data* od;
} u2_;
// The address offset within the input section or the Output_data.
Address address_;
// This is GSYM_CODE for a global symbol, or SECTION_CODE for a
// relocation against an output section, or TARGET_CODE for a target
// specific relocation, or INVALID_CODE for an uninitialized value.
// Otherwise, for a local symbol (this->is_section_symbol_ is
// false), the local symbol index. For a local section symbol
// (this->is_section_symbol_ is true), the section index in the
// input file.
unsigned int local_sym_index_;
// The reloc type--a processor specific code.
unsigned int type_ : 28;
// True if the relocation is a RELATIVE relocation.
bool is_relative_ : 1;
// True if the relocation is one which should not use
// a symbol, but which obtains its addend from a symbol.
bool is_symbolless_ : 1;
// True if the relocation is against a section symbol.
bool is_section_symbol_ : 1;
// True if the addend should be the PLT offset.
// (Used only for RELA, but stored here for space.)
bool use_plt_offset_ : 1;
// If the reloc address is an input section in an object, the
// section index. This is INVALID_CODE if the reloc address is
// specified in some other way.
unsigned int shndx_;
};
// The SHT_RELA version of Output_reloc<>. This is just derived from
// the SHT_REL version of Output_reloc, but it adds an addend.
template<bool dynamic, int size, bool big_endian>
class Output_reloc<elfcpp::SHT_RELA, dynamic, size, big_endian>
{
public:
typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
typedef typename elfcpp::Elf_types<size>::Elf_Addr Addend;
// An uninitialized entry.
Output_reloc()
: rel_()
{ }
// A reloc against a global symbol.
Output_reloc(Symbol* gsym, unsigned int type, Output_data* od,
Address address, Addend addend, bool is_relative,
bool is_symbolless, bool use_plt_offset)
: rel_(gsym, type, od, address, is_relative, is_symbolless,
use_plt_offset),
addend_(addend)
{ }
Output_reloc(Symbol* gsym, unsigned int type,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address, Addend addend,
bool is_relative, bool is_symbolless, bool use_plt_offset)
: rel_(gsym, type, relobj, shndx, address, is_relative,
is_symbolless, use_plt_offset), addend_(addend)
{ }
// A reloc against a local symbol.
Output_reloc(Sized_relobj<size, big_endian>* relobj,
unsigned int local_sym_index, unsigned int type,
Output_data* od, Address address,
Addend addend, bool is_relative,
bool is_symbolless, bool is_section_symbol,
bool use_plt_offset)
: rel_(relobj, local_sym_index, type, od, address, is_relative,
is_symbolless, is_section_symbol, use_plt_offset),
addend_(addend)
{ }
Output_reloc(Sized_relobj<size, big_endian>* relobj,
unsigned int local_sym_index, unsigned int type,
unsigned int shndx, Address address,
Addend addend, bool is_relative,
bool is_symbolless, bool is_section_symbol,
bool use_plt_offset)
: rel_(relobj, local_sym_index, type, shndx, address, is_relative,
is_symbolless, is_section_symbol, use_plt_offset),
addend_(addend)
{ }
// A reloc against the STT_SECTION symbol of an output section.
Output_reloc(Output_section* os, unsigned int type, Output_data* od,
Address address, Addend addend, bool is_relative)
: rel_(os, type, od, address, is_relative), addend_(addend)
{ }
Output_reloc(Output_section* os, unsigned int type,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address, Addend addend,
bool is_relative)
: rel_(os, type, relobj, shndx, address, is_relative), addend_(addend)
{ }
// An absolute or relative relocation with no symbol.
Output_reloc(unsigned int type, Output_data* od, Address address,
Addend addend, bool is_relative)
: rel_(type, od, address, is_relative), addend_(addend)
{ }
Output_reloc(unsigned int type, Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address, Addend addend,
bool is_relative)
: rel_(type, relobj, shndx, address, is_relative), addend_(addend)
{ }
// A target specific relocation. The target will be called to get
// the symbol index and the addend, passing ARG. The type and
// offset will be set as for other relocation types.
Output_reloc(unsigned int type, void* arg, Output_data* od,
Address address, Addend addend)
: rel_(type, arg, od, address), addend_(addend)
{ }
Output_reloc(unsigned int type, void* arg,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address, Addend addend)
: rel_(type, arg, relobj, shndx, address), addend_(addend)
{ }
// Return whether this is a RELATIVE relocation.
bool
is_relative() const
{ return this->rel_.is_relative(); }
// Return whether this is a relocation which should not use
// a symbol, but which obtains its addend from a symbol.
bool
is_symbolless() const
{ return this->rel_.is_symbolless(); }
// If this relocation is against an input section, return the
// relocatable object containing the input section.
Sized_relobj<size, big_endian>*
get_relobj() const
{ return this->rel_.get_relobj(); }
// Write the reloc entry to an output view.
void
write(unsigned char* pov) const;
// Return whether this reloc should be sorted before the argument
// when sorting dynamic relocs.
bool
sort_before(const Output_reloc<elfcpp::SHT_RELA, dynamic, size, big_endian>&
r2) const
{
int i = this->rel_.compare(r2.rel_);
if (i < 0)
return true;
else if (i > 0)
return false;
else
return this->addend_ < r2.addend_;
}
private:
// The basic reloc.
Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian> rel_;
// The addend.
Addend addend_;
};
// Output_data_reloc_generic is a non-template base class for
// Output_data_reloc_base. This gives the generic code a way to hold
// a pointer to a reloc section.
class Output_data_reloc_generic : public Output_section_data_build
{
public:
Output_data_reloc_generic(int size, bool sort_relocs)
: Output_section_data_build(Output_data::default_alignment_for_size(size)),
relative_reloc_count_(0), sort_relocs_(sort_relocs)
{ }
// Return the number of relative relocs in this section.
size_t
relative_reloc_count() const
{ return this->relative_reloc_count_; }
// Whether we should sort the relocs.
bool
sort_relocs() const
{ return this->sort_relocs_; }
// Add a reloc of type TYPE against the global symbol GSYM. The
// relocation applies to the data at offset ADDRESS within OD.
virtual void
add_global_generic(Symbol* gsym, unsigned int type, Output_data* od,
uint64_t address, uint64_t addend) = 0;
// Add a reloc of type TYPE against the global symbol GSYM. The
// relocation applies to data at offset ADDRESS within section SHNDX
// of object file RELOBJ. OD is the associated output section.
virtual void
add_global_generic(Symbol* gsym, unsigned int type, Output_data* od,
Relobj* relobj, unsigned int shndx, uint64_t address,
uint64_t addend) = 0;
// Add a reloc of type TYPE against the local symbol LOCAL_SYM_INDEX
// in RELOBJ. The relocation applies to the data at offset ADDRESS
// within OD.
virtual void
add_local_generic(Relobj* relobj, unsigned int local_sym_index,
unsigned int type, Output_data* od, uint64_t address,
uint64_t addend) = 0;
// Add a reloc of type TYPE against the local symbol LOCAL_SYM_INDEX
// in RELOBJ. The relocation applies to the data at offset ADDRESS
// within section SHNDX of RELOBJ. OD is the associated output
// section.
virtual void
add_local_generic(Relobj* relobj, unsigned int local_sym_index,
unsigned int type, Output_data* od, unsigned int shndx,
uint64_t address, uint64_t addend) = 0;
// Add a reloc of type TYPE against the STT_SECTION symbol of the
// output section OS. The relocation applies to the data at offset
// ADDRESS within OD.
virtual void
add_output_section_generic(Output_section *os, unsigned int type,
Output_data* od, uint64_t address,
uint64_t addend) = 0;
// Add a reloc of type TYPE against the STT_SECTION symbol of the
// output section OS. The relocation applies to the data at offset
// ADDRESS within section SHNDX of RELOBJ. OD is the associated
// output section.
virtual void
add_output_section_generic(Output_section* os, unsigned int type,
Output_data* od, Relobj* relobj,
unsigned int shndx, uint64_t address,
uint64_t addend) = 0;
protected:
// Note that we've added another relative reloc.
void
bump_relative_reloc_count()
{ ++this->relative_reloc_count_; }
private:
// The number of relative relocs added to this section. This is to
// support DT_RELCOUNT.
size_t relative_reloc_count_;
// Whether to sort the relocations when writing them out, to make
// the dynamic linker more efficient.
bool sort_relocs_;
};
// Output_data_reloc is used to manage a section containing relocs.
// SH_TYPE is either elfcpp::SHT_REL or elfcpp::SHT_RELA. DYNAMIC
// indicates whether this is a dynamic relocation or a normal
// relocation. Output_data_reloc_base is a base class.
// Output_data_reloc is the real class, which we specialize based on
// the reloc type.
template<int sh_type, bool dynamic, int size, bool big_endian>
class Output_data_reloc_base : public Output_data_reloc_generic
{
public:
typedef Output_reloc<sh_type, dynamic, size, big_endian> Output_reloc_type;
typedef typename Output_reloc_type::Address Address;
static const int reloc_size =
Reloc_types<sh_type, size, big_endian>::reloc_size;
// Construct the section.
Output_data_reloc_base(bool sort_relocs)
: Output_data_reloc_generic(size, sort_relocs)
{ }
protected:
// Write out the data.
void
do_write(Output_file*);
// Set the entry size and the link.
void
do_adjust_output_section(Output_section* os);
// Write to a map file.
void
do_print_to_mapfile(Mapfile* mapfile) const
{
mapfile->print_output_data(this,
(dynamic
? _("** dynamic relocs")
: _("** relocs")));
}
// Add a relocation entry.
void
add(Output_data* od, const Output_reloc_type& reloc)
{
this->relocs_.push_back(reloc);
this->set_current_data_size(this->relocs_.size() * reloc_size);
if (dynamic)
od->add_dynamic_reloc();
if (reloc.is_relative())
this->bump_relative_reloc_count();
Sized_relobj<size, big_endian>* relobj = reloc.get_relobj();
if (relobj != NULL)
relobj->add_dyn_reloc(this->relocs_.size() - 1);
}
private:
typedef std::vector<Output_reloc_type> Relocs;
// The class used to sort the relocations.
struct Sort_relocs_comparison
{
bool
operator()(const Output_reloc_type& r1, const Output_reloc_type& r2) const
{ return r1.sort_before(r2); }
};
// The relocations in this section.
Relocs relocs_;
};
// The class which callers actually create.
template<int sh_type, bool dynamic, int size, bool big_endian>
class Output_data_reloc;
// The SHT_REL version of Output_data_reloc.
template<bool dynamic, int size, bool big_endian>
class Output_data_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>
: public Output_data_reloc_base<elfcpp::SHT_REL, dynamic, size, big_endian>
{
private:
typedef Output_data_reloc_base<elfcpp::SHT_REL, dynamic, size,
big_endian> Base;
public:
typedef typename Base::Output_reloc_type Output_reloc_type;
typedef typename Output_reloc_type::Address Address;
Output_data_reloc(bool sr)
: Output_data_reloc_base<elfcpp::SHT_REL, dynamic, size, big_endian>(sr)
{ }
// Add a reloc against a global symbol.
void
add_global(Symbol* gsym, unsigned int type, Output_data* od, Address address)
{
this->add(od, Output_reloc_type(gsym, type, od, address,
false, false, false));
}
void
add_global(Symbol* gsym, unsigned int type, Output_data* od,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address)
{
this->add(od, Output_reloc_type(gsym, type, relobj, shndx, address,
false, false, false));
}
void
add_global_generic(Symbol* gsym, unsigned int type, Output_data* od,
uint64_t address, uint64_t addend)
{
gold_assert(addend == 0);
this->add(od, Output_reloc_type(gsym, type, od,
convert_types<Address, uint64_t>(address),
false, false, false));
}
void
add_global_generic(Symbol* gsym, unsigned int type, Output_data* od,
Relobj* relobj, unsigned int shndx, uint64_t address,
uint64_t addend)
{
gold_assert(addend == 0);
Sized_relobj<size, big_endian>* sized_relobj =
static_cast<Sized_relobj<size, big_endian>*>(relobj);
this->add(od, Output_reloc_type(gsym, type, sized_relobj, shndx,
convert_types<Address, uint64_t>(address),
false, false, false));
}
// Add a RELATIVE reloc against a global symbol. The final relocation
// will not reference the symbol.
void
add_global_relative(Symbol* gsym, unsigned int type, Output_data* od,
Address address)
{
this->add(od, Output_reloc_type(gsym, type, od, address, true, true,
false));
}
void
add_global_relative(Symbol* gsym, unsigned int type, Output_data* od,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address)
{
this->add(od, Output_reloc_type(gsym, type, relobj, shndx, address,
true, true, false));
}
// Add a global relocation which does not use a symbol for the relocation,
// but which gets its addend from a symbol.
void
add_symbolless_global_addend(Symbol* gsym, unsigned int type,
Output_data* od, Address address)
{
this->add(od, Output_reloc_type(gsym, type, od, address, false, true,
false));
}
void
add_symbolless_global_addend(Symbol* gsym, unsigned int type,
Output_data* od,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address)
{
this->add(od, Output_reloc_type(gsym, type, relobj, shndx, address,
false, true, false));
}
// Add a reloc against a local symbol.
void
add_local(Sized_relobj<size, big_endian>* relobj,
unsigned int local_sym_index, unsigned int type,
Output_data* od, Address address)
{
this->add(od, Output_reloc_type(relobj, local_sym_index, type, od,
address, false, false, false, false));
}
void
add_local(Sized_relobj<size, big_endian>* relobj,
unsigned int local_sym_index, unsigned int type,
Output_data* od, unsigned int shndx, Address address)
{
this->add(od, Output_reloc_type(relobj, local_sym_index, type, shndx,
address, false, false, false, false));
}
void
add_local_generic(Relobj* relobj, unsigned int local_sym_index,
unsigned int type, Output_data* od, uint64_t address,
uint64_t addend)
{
gold_assert(addend == 0);
Sized_relobj<size, big_endian>* sized_relobj =
static_cast<Sized_relobj<size, big_endian> *>(relobj);
this->add(od, Output_reloc_type(sized_relobj, local_sym_index, type, od,
convert_types<Address, uint64_t>(address),
false, false, false, false));
}
void
add_local_generic(Relobj* relobj, unsigned int local_sym_index,
unsigned int type, Output_data* od, unsigned int shndx,
uint64_t address, uint64_t addend)
{
gold_assert(addend == 0);
Sized_relobj<size, big_endian>* sized_relobj =
static_cast<Sized_relobj<size, big_endian>*>(relobj);
this->add(od, Output_reloc_type(sized_relobj, local_sym_index, type, shndx,
convert_types<Address, uint64_t>(address),
false, false, false, false));
}
// Add a RELATIVE reloc against a local symbol.
void
add_local_relative(Sized_relobj<size, big_endian>* relobj,
unsigned int local_sym_index, unsigned int type,
Output_data* od, Address address)
{
this->add(od, Output_reloc_type(relobj, local_sym_index, type, od,
address, true, true, false, false));
}
void
add_local_relative(Sized_relobj<size, big_endian>* relobj,
unsigned int local_sym_index, unsigned int type,
Output_data* od, unsigned int shndx, Address address)
{
this->add(od, Output_reloc_type(relobj, local_sym_index, type, shndx,
address, true, true, false, false));
}
// Add a local relocation which does not use a symbol for the relocation,
// but which gets its addend from a symbol.
void
add_symbolless_local_addend(Sized_relobj<size, big_endian>* relobj,
unsigned int local_sym_index, unsigned int type,
Output_data* od, Address address)
{
this->add(od, Output_reloc_type(relobj, local_sym_index, type, od,
address, false, true, false, false));
}
void
add_symbolless_local_addend(Sized_relobj<size, big_endian>* relobj,
unsigned int local_sym_index, unsigned int type,
Output_data* od, unsigned int shndx,
Address address)
{
this->add(od, Output_reloc_type(relobj, local_sym_index, type, shndx,
address, false, true, false, false));
}
// Add a reloc against a local section symbol. This will be
// converted into a reloc against the STT_SECTION symbol of the
// output section.
void
add_local_section(Sized_relobj<size, big_endian>* relobj,
unsigned int input_shndx, unsigned int type,
Output_data* od, Address address)
{
this->add(od, Output_reloc_type(relobj, input_shndx, type, od,
address, false, false, true, false));
}
void
add_local_section(Sized_relobj<size, big_endian>* relobj,
unsigned int input_shndx, unsigned int type,
Output_data* od, unsigned int shndx, Address address)
{
this->add(od, Output_reloc_type(relobj, input_shndx, type, shndx,
address, false, false, true, false));
}
// A reloc against the STT_SECTION symbol of an output section.
// OS is the Output_section that the relocation refers to; OD is
// the Output_data object being relocated.
void
add_output_section(Output_section* os, unsigned int type,
Output_data* od, Address address)
{ this->add(od, Output_reloc_type(os, type, od, address, false)); }
void
add_output_section(Output_section* os, unsigned int type, Output_data* od,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address)
{ this->add(od, Output_reloc_type(os, type, relobj, shndx, address, false)); }
void
add_output_section_generic(Output_section* os, unsigned int type,
Output_data* od, uint64_t address,
uint64_t addend)
{
gold_assert(addend == 0);
this->add(od, Output_reloc_type(os, type, od,
convert_types<Address, uint64_t>(address),
false));
}
void
add_output_section_generic(Output_section* os, unsigned int type,
Output_data* od, Relobj* relobj,
unsigned int shndx, uint64_t address,
uint64_t addend)
{
gold_assert(addend == 0);
Sized_relobj<size, big_endian>* sized_relobj =
static_cast<Sized_relobj<size, big_endian>*>(relobj);
this->add(od, Output_reloc_type(os, type, sized_relobj, shndx,
convert_types<Address, uint64_t>(address),
false));
}
// As above, but the reloc TYPE is relative
void
add_output_section_relative(Output_section* os, unsigned int type,
Output_data* od, Address address)
{ this->add(od, Output_reloc_type(os, type, od, address, true)); }
void
add_output_section_relative(Output_section* os, unsigned int type,
Output_data* od,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address)
{ this->add(od, Output_reloc_type(os, type, relobj, shndx, address, true)); }
// Add an absolute relocation.
void
add_absolute(unsigned int type, Output_data* od, Address address)
{ this->add(od, Output_reloc_type(type, od, address, false)); }
void
add_absolute(unsigned int type, Output_data* od,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address)
{ this->add(od, Output_reloc_type(type, relobj, shndx, address, false)); }
// Add a relative relocation
void
add_relative(unsigned int type, Output_data* od, Address address)
{ this->add(od, Output_reloc_type(type, od, address, true)); }
void
add_relative(unsigned int type, Output_data* od,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address)
{ this->add(od, Output_reloc_type(type, relobj, shndx, address, true)); }
// Add a target specific relocation. A target which calls this must
// define the reloc_symbol_index and reloc_addend virtual functions.
void
add_target_specific(unsigned int type, void* arg, Output_data* od,
Address address)
{ this->add(od, Output_reloc_type(type, arg, od, address)); }
void
add_target_specific(unsigned int type, void* arg, Output_data* od,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address)
{ this->add(od, Output_reloc_type(type, arg, relobj, shndx, address)); }
};
// The SHT_RELA version of Output_data_reloc.
template<bool dynamic, int size, bool big_endian>
class Output_data_reloc<elfcpp::SHT_RELA, dynamic, size, big_endian>
: public Output_data_reloc_base<elfcpp::SHT_RELA, dynamic, size, big_endian>
{
private:
typedef Output_data_reloc_base<elfcpp::SHT_RELA, dynamic, size,
big_endian> Base;
public:
typedef typename Base::Output_reloc_type Output_reloc_type;
typedef typename Output_reloc_type::Address Address;
typedef typename Output_reloc_type::Addend Addend;
Output_data_reloc(bool sr)
: Output_data_reloc_base<elfcpp::SHT_RELA, dynamic, size, big_endian>(sr)
{ }
// Add a reloc against a global symbol.
void
add_global(Symbol* gsym, unsigned int type, Output_data* od,
Address address, Addend addend)
{
this->add(od, Output_reloc_type(gsym, type, od, address, addend,
false, false, false));
}
void
add_global(Symbol* gsym, unsigned int type, Output_data* od,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address,
Addend addend)
{
this->add(od, Output_reloc_type(gsym, type, relobj, shndx, address,
addend, false, false, false));
}
void
add_global_generic(Symbol* gsym, unsigned int type, Output_data* od,
uint64_t address, uint64_t addend)
{
this->add(od, Output_reloc_type(gsym, type, od,
convert_types<Address, uint64_t>(address),
convert_types<Addend, uint64_t>(addend),
false, false, false));
}
void
add_global_generic(Symbol* gsym, unsigned int type, Output_data* od,
Relobj* relobj, unsigned int shndx, uint64_t address,
uint64_t addend)
{
Sized_relobj<size, big_endian>* sized_relobj =
static_cast<Sized_relobj<size, big_endian>*>(relobj);
this->add(od, Output_reloc_type(gsym, type, sized_relobj, shndx,
convert_types<Address, uint64_t>(address),
convert_types<Addend, uint64_t>(addend),
false, false, false));
}
// Add a RELATIVE reloc against a global symbol. The final output
// relocation will not reference the symbol, but we must keep the symbol
// information long enough to set the addend of the relocation correctly
// when it is written.
void
add_global_relative(Symbol* gsym, unsigned int type, Output_data* od,
Address address, Addend addend, bool use_plt_offset)
{
this->add(od, Output_reloc_type(gsym, type, od, address, addend, true,
true, use_plt_offset));
}
void
add_global_relative(Symbol* gsym, unsigned int type, Output_data* od,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address, Addend addend,
bool use_plt_offset)
{
this->add(od, Output_reloc_type(gsym, type, relobj, shndx, address,
addend, true, true, use_plt_offset));
}
// Add a global relocation which does not use a symbol for the relocation,
// but which gets its addend from a symbol.
void
add_symbolless_global_addend(Symbol* gsym, unsigned int type, Output_data* od,
Address address, Addend addend)
{
this->add(od, Output_reloc_type(gsym, type, od, address, addend,
false, true, false));
}
void
add_symbolless_global_addend(Symbol* gsym, unsigned int type,
Output_data* od,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address,
Addend addend)
{
this->add(od, Output_reloc_type(gsym, type, relobj, shndx, address,
addend, false, true, false));
}
// Add a reloc against a local symbol.
void
add_local(Sized_relobj<size, big_endian>* relobj,
unsigned int local_sym_index, unsigned int type,
Output_data* od, Address address, Addend addend)
{
this->add(od, Output_reloc_type(relobj, local_sym_index, type, od, address,
addend, false, false, false, false));
}
void
add_local(Sized_relobj<size, big_endian>* relobj,
unsigned int local_sym_index, unsigned int type,
Output_data* od, unsigned int shndx, Address address,
Addend addend)
{
this->add(od, Output_reloc_type(relobj, local_sym_index, type, shndx,
address, addend, false, false, false,
false));
}
void
add_local_generic(Relobj* relobj, unsigned int local_sym_index,
unsigned int type, Output_data* od, uint64_t address,
uint64_t addend)
{
Sized_relobj<size, big_endian>* sized_relobj =
static_cast<Sized_relobj<size, big_endian> *>(relobj);
this->add(od, Output_reloc_type(sized_relobj, local_sym_index, type, od,
convert_types<Address, uint64_t>(address),
convert_types<Addend, uint64_t>(addend),
false, false, false, false));
}
void
add_local_generic(Relobj* relobj, unsigned int local_sym_index,
unsigned int type, Output_data* od, unsigned int shndx,
uint64_t address, uint64_t addend)
{
Sized_relobj<size, big_endian>* sized_relobj =
static_cast<Sized_relobj<size, big_endian>*>(relobj);
this->add(od, Output_reloc_type(sized_relobj, local_sym_index, type, shndx,
convert_types<Address, uint64_t>(address),
convert_types<Addend, uint64_t>(addend),
false, false, false, false));
}
// Add a RELATIVE reloc against a local symbol.
void
add_local_relative(Sized_relobj<size, big_endian>* relobj,
unsigned int local_sym_index, unsigned int type,
Output_data* od, Address address, Addend addend,
bool use_plt_offset)
{
this->add(od, Output_reloc_type(relobj, local_sym_index, type, od, address,
addend, true, true, false,
use_plt_offset));
}
void
add_local_relative(Sized_relobj<size, big_endian>* relobj,
unsigned int local_sym_index, unsigned int type,
Output_data* od, unsigned int shndx, Address address,
Addend addend, bool use_plt_offset)
{
this->add(od, Output_reloc_type(relobj, local_sym_index, type, shndx,
address, addend, true, true, false,
use_plt_offset));
}
// Add a local relocation which does not use a symbol for the relocation,
// but which gets it's addend from a symbol.
void
add_symbolless_local_addend(Sized_relobj<size, big_endian>* relobj,
unsigned int local_sym_index, unsigned int type,
Output_data* od, Address address, Addend addend)
{
this->add(od, Output_reloc_type(relobj, local_sym_index, type, od, address,
addend, false, true, false, false));
}
void
add_symbolless_local_addend(Sized_relobj<size, big_endian>* relobj,
unsigned int local_sym_index, unsigned int type,
Output_data* od, unsigned int shndx,
Address address, Addend addend)
{
this->add(od, Output_reloc_type(relobj, local_sym_index, type, shndx,
address, addend, false, true, false,
false));
}
// Add a reloc against a local section symbol. This will be
// converted into a reloc against the STT_SECTION symbol of the
// output section.
void
add_local_section(Sized_relobj<size, big_endian>* relobj,
unsigned int input_shndx, unsigned int type,
Output_data* od, Address address, Addend addend)
{
this->add(od, Output_reloc_type(relobj, input_shndx, type, od, address,
addend, false, false, true, false));
}
void
add_local_section(Sized_relobj<size, big_endian>* relobj,
unsigned int input_shndx, unsigned int type,
Output_data* od, unsigned int shndx, Address address,
Addend addend)
{
this->add(od, Output_reloc_type(relobj, input_shndx, type, shndx,
address, addend, false, false, true,
false));
}
// A reloc against the STT_SECTION symbol of an output section.
void
add_output_section(Output_section* os, unsigned int type, Output_data* od,
Address address, Addend addend)
{ this->add(od, Output_reloc_type(os, type, od, address, addend, false)); }
void
add_output_section(Output_section* os, unsigned int type, Output_data* od,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address, Addend addend)
{
this->add(od, Output_reloc_type(os, type, relobj, shndx, address,
addend, false));
}
void
add_output_section_generic(Output_section* os, unsigned int type,
Output_data* od, uint64_t address,
uint64_t addend)
{
this->add(od, Output_reloc_type(os, type, od,
convert_types<Address, uint64_t>(address),
convert_types<Addend, uint64_t>(addend),
false));
}
void
add_output_section_generic(Output_section* os, unsigned int type,
Output_data* od, Relobj* relobj,
unsigned int shndx, uint64_t address,
uint64_t addend)
{
Sized_relobj<size, big_endian>* sized_relobj =
static_cast<Sized_relobj<size, big_endian>*>(relobj);
this->add(od, Output_reloc_type(os, type, sized_relobj, shndx,
convert_types<Address, uint64_t>(address),
convert_types<Addend, uint64_t>(addend),
false));
}
// As above, but the reloc TYPE is relative
void
add_output_section_relative(Output_section* os, unsigned int type,
Output_data* od, Address address, Addend addend)
{ this->add(od, Output_reloc_type(os, type, od, address, addend, true)); }
void
add_output_section_relative(Output_section* os, unsigned int type,
Output_data* od,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address,
Addend addend)
{
this->add(od, Output_reloc_type(os, type, relobj, shndx,
address, addend, true));
}
// Add an absolute relocation.
void
add_absolute(unsigned int type, Output_data* od, Address address,
Addend addend)
{ this->add(od, Output_reloc_type(type, od, address, addend, false)); }
void
add_absolute(unsigned int type, Output_data* od,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address, Addend addend)
{
this->add(od, Output_reloc_type(type, relobj, shndx, address, addend,
false));
}
// Add a relative relocation
void
add_relative(unsigned int type, Output_data* od, Address address,
Addend addend)
{ this->add(od, Output_reloc_type(type, od, address, addend, true)); }
void
add_relative(unsigned int type, Output_data* od,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address, Addend addend)
{
this->add(od, Output_reloc_type(type, relobj, shndx, address, addend,
true));
}
// Add a target specific relocation. A target which calls this must
// define the reloc_symbol_index and reloc_addend virtual functions.
void
add_target_specific(unsigned int type, void* arg, Output_data* od,
Address address, Addend addend)
{ this->add(od, Output_reloc_type(type, arg, od, address, addend)); }
void
add_target_specific(unsigned int type, void* arg, Output_data* od,
Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address, Addend addend)
{
this->add(od, Output_reloc_type(type, arg, relobj, shndx, address,
addend));
}
};
// Output_relocatable_relocs represents a relocation section in a
// relocatable link. The actual data is written out in the target
// hook relocate_relocs. This just saves space for it.
template<int sh_type, int size, bool big_endian>
class Output_relocatable_relocs : public Output_section_data
{
public:
Output_relocatable_relocs(Relocatable_relocs* rr)
: Output_section_data(Output_data::default_alignment_for_size(size)),
rr_(rr)
{ }
void
set_final_data_size();
// Write out the data. There is nothing to do here.
void
do_write(Output_file*)
{ }
// Write to a map file.
void
do_print_to_mapfile(Mapfile* mapfile) const
{ mapfile->print_output_data(this, _("** relocs")); }
private:
// The relocs associated with this input section.
Relocatable_relocs* rr_;
};
// Handle a GROUP section.
template<int size, bool big_endian>
class Output_data_group : public Output_section_data
{
public:
// The constructor clears *INPUT_SHNDXES.
Output_data_group(Sized_relobj_file<size, big_endian>* relobj,
section_size_type entry_count,
elfcpp::Elf_Word flags,
std::vector<unsigned int>* input_shndxes);
void
do_write(Output_file*);
// Write to a map file.
void
do_print_to_mapfile(Mapfile* mapfile) const
{ mapfile->print_output_data(this, _("** group")); }
// Set final data size.
void
set_final_data_size()
{ this->set_data_size((this->input_shndxes_.size() + 1) * 4); }
private:
// The input object.
Sized_relobj_file<size, big_endian>* relobj_;
// The group flag word.
elfcpp::Elf_Word flags_;
// The section indexes of the input sections in this group.
std::vector<unsigned int> input_shndxes_;
};
// Output_data_got is used to manage a GOT. Each entry in the GOT is
// for one symbol--either a global symbol or a local symbol in an
// object. The target specific code adds entries to the GOT as
// needed. The GOT_SIZE template parameter is the size in bits of a
// GOT entry, typically 32 or 64.
class Output_data_got_base : public Output_section_data_build
{
public:
Output_data_got_base(uint64_t align)
: Output_section_data_build(align)
{ }
Output_data_got_base(off_t data_size, uint64_t align)
: Output_section_data_build(data_size, align)
{ }
// Reserve the slot at index I in the GOT.
void
reserve_slot(unsigned int i)
{ this->do_reserve_slot(i); }
protected:
// Reserve the slot at index I in the GOT.
virtual void
do_reserve_slot(unsigned int i) = 0;
};
template<int got_size, bool big_endian>
class Output_data_got : public Output_data_got_base
{
public:
typedef typename elfcpp::Elf_types<got_size>::Elf_Addr Valtype;
Output_data_got()
: Output_data_got_base(Output_data::default_alignment_for_size(got_size)),
entries_(), free_list_()
{ }
Output_data_got(off_t data_size)
: Output_data_got_base(data_size,
Output_data::default_alignment_for_size(got_size)),
entries_(), free_list_()
{
// For an incremental update, we have an existing GOT section.
// Initialize the list of entries and the free list.
this->entries_.resize(data_size / (got_size / 8));
this->free_list_.init(data_size, false);
}
// Add an entry for a global symbol to the GOT. Return true if this
// is a new GOT entry, false if the symbol was already in the GOT.
bool
add_global(Symbol* gsym, unsigned int got_type);
// Like add_global, but use the PLT offset of the global symbol if
// it has one.
bool
add_global_plt(Symbol* gsym, unsigned int got_type);
// Like add_global, but for a TLS symbol where the value will be
// offset using Target::tls_offset_for_global.
bool
add_global_tls(Symbol* gsym, unsigned int got_type)
{ return add_global_plt(gsym, got_type); }
// Add an entry for a global symbol to the GOT, and add a dynamic
// relocation of type R_TYPE for the GOT entry.
void
add_global_with_rel(Symbol* gsym, unsigned int got_type,
Output_data_reloc_generic* rel_dyn, unsigned int r_type);
// Add a pair of entries for a global symbol to the GOT, and add
// dynamic relocations of type R_TYPE_1 and R_TYPE_2, respectively.
void
add_global_pair_with_rel(Symbol* gsym, unsigned int got_type,
Output_data_reloc_generic* rel_dyn,
unsigned int r_type_1, unsigned int r_type_2);
// Add an entry for a local symbol to the GOT. This returns true if
// this is a new GOT entry, false if the symbol already has a GOT
// entry.
bool
add_local(Relobj* object, unsigned int sym_index, unsigned int got_type);
// Like add_local, but use the PLT offset of the local symbol if it
// has one.
bool
add_local_plt(Relobj* object, unsigned int sym_index, unsigned int got_type);
// Like add_local, but for a TLS symbol where the value will be
// offset using Target::tls_offset_for_local.
bool
add_local_tls(Relobj* object, unsigned int sym_index, unsigned int got_type)
{ return add_local_plt(object, sym_index, got_type); }
// Add an entry for a local symbol to the GOT, and add a dynamic
// relocation of type R_TYPE for the GOT entry.
void
add_local_with_rel(Relobj* object, unsigned int sym_index,
unsigned int got_type, Output_data_reloc_generic* rel_dyn,
unsigned int r_type);
// Add a pair of entries for a local symbol to the GOT, and add
// a dynamic relocation of type R_TYPE using the section symbol of
// the output section to which input section SHNDX maps, on the first.
// The first got entry will have a value of zero, the second the
// value of the local symbol.
void
add_local_pair_with_rel(Relobj* object, unsigned int sym_index,
unsigned int shndx, unsigned int got_type,
Output_data_reloc_generic* rel_dyn,
unsigned int r_type);
// Add a pair of entries for a local symbol to the GOT, and add
// a dynamic relocation of type R_TYPE using STN_UNDEF on the first.
// The first got entry will have a value of zero, the second the
// value of the local symbol offset by Target::tls_offset_for_local.
void
add_local_tls_pair(Relobj* object, unsigned int sym_index,
unsigned int got_type,
Output_data_reloc_generic* rel_dyn,
unsigned int r_type);
// Add a constant to the GOT. This returns the offset of the new
// entry from the start of the GOT.
unsigned int
add_constant(Valtype constant)
{
unsigned int got_offset = this->add_got_entry(Got_entry(constant));
return got_offset;
}
// Replace GOT entry I with a new constant.
void
replace_constant(unsigned int i, Valtype constant)
{
this->replace_got_entry(i, Got_entry(constant));
}
// Reserve a slot in the GOT for a local symbol.
void
reserve_local(unsigned int i, Relobj* object, unsigned int sym_index,
unsigned int got_type);
// Reserve a slot in the GOT for a global symbol.
void
reserve_global(unsigned int i, Symbol* gsym, unsigned int got_type);
protected:
// Write out the GOT table.
void
do_write(Output_file*);
// Write to a map file.
void
do_print_to_mapfile(Mapfile* mapfile) const
{ mapfile->print_output_data(this, _("** GOT")); }
// Reserve the slot at index I in the GOT.
virtual void
do_reserve_slot(unsigned int i)
{ this->free_list_.remove(i * got_size / 8, (i + 1) * got_size / 8); }
// Return the number of words in the GOT.
unsigned int
num_entries () const
{ return this->entries_.size(); }
// Return the offset into the GOT of GOT entry I.
unsigned int
got_offset(unsigned int i) const
{ return i * (got_size / 8); }
private:
// This POD class holds a single GOT entry.
class Got_entry
{
public:
// Create a zero entry.
Got_entry()
: local_sym_index_(RESERVED_CODE), use_plt_or_tls_offset_(false)
{ this->u_.constant = 0; }
// Create a global symbol entry.
Got_entry(Symbol* gsym, bool use_plt_or_tls_offset)
: local_sym_index_(GSYM_CODE),
use_plt_or_tls_offset_(use_plt_or_tls_offset)
{ this->u_.gsym = gsym; }
// Create a local symbol entry.
Got_entry(Relobj* object, unsigned int local_sym_index,
bool use_plt_or_tls_offset)
: local_sym_index_(local_sym_index),
use_plt_or_tls_offset_(use_plt_or_tls_offset)
{
gold_assert(local_sym_index != GSYM_CODE
&& local_sym_index != CONSTANT_CODE
&& local_sym_index != RESERVED_CODE
&& local_sym_index == this->local_sym_index_);
this->u_.object = object;
}
// Create a constant entry. The constant is a host value--it will
// be swapped, if necessary, when it is written out.
explicit Got_entry(Valtype constant)
: local_sym_index_(CONSTANT_CODE), use_plt_or_tls_offset_(false)
{ this->u_.constant = constant; }
// Write the GOT entry to an output view.
void
write(unsigned int got_indx, unsigned char* pov) const;
private:
enum
{
GSYM_CODE = 0x7fffffff,
CONSTANT_CODE = 0x7ffffffe,
RESERVED_CODE = 0x7ffffffd
};
union
{
// For a local symbol, the object.
Relobj* object;
// For a global symbol, the symbol.
Symbol* gsym;
// For a constant, the constant.
Valtype constant;
} u_;
// For a local symbol, the local symbol index. This is GSYM_CODE
// for a global symbol, or CONSTANT_CODE for a constant.
unsigned int local_sym_index_ : 31;
// Whether to use the PLT offset of the symbol if it has one.
// For TLS symbols, whether to offset the symbol value.
bool use_plt_or_tls_offset_ : 1;
};
typedef std::vector<Got_entry> Got_entries;
// Create a new GOT entry and return its offset.
unsigned int
add_got_entry(Got_entry got_entry);
// Create a pair of new GOT entries and return the offset of the first.
unsigned int
add_got_entry_pair(Got_entry got_entry_1, Got_entry got_entry_2);
// Replace GOT entry I with a new value.
void
replace_got_entry(unsigned int i, Got_entry got_entry);
// Return the offset into the GOT of the last entry added.
unsigned int
last_got_offset() const
{ return this->got_offset(this->num_entries() - 1); }
// Set the size of the section.
void
set_got_size()
{ this->set_current_data_size(this->got_offset(this->num_entries())); }
// The list of GOT entries.
Got_entries entries_;
// List of available regions within the section, for incremental
// update links.
Free_list free_list_;
};
// Output_data_dynamic is used to hold the data in SHT_DYNAMIC
// section.
class Output_data_dynamic : public Output_section_data
{
public:
Output_data_dynamic(Stringpool* pool)
: Output_section_data(Output_data::default_alignment()),
entries_(), pool_(pool)
{ }
// Add a new dynamic entry with a fixed numeric value.
void
add_constant(elfcpp::DT tag, unsigned int val)
{ this->add_entry(Dynamic_entry(tag, val)); }
// Add a new dynamic entry with the address of output data.
void
add_section_address(elfcpp::DT tag, const Output_data* od)
{ this->add_entry(Dynamic_entry(tag, od, false)); }
// Add a new dynamic entry with the address of output data
// plus a constant offset.
void
add_section_plus_offset(elfcpp::DT tag, const Output_data* od,
unsigned int offset)
{ this->add_entry(Dynamic_entry(tag, od, offset)); }
// Add a new dynamic entry with the size of output data.
void
add_section_size(elfcpp::DT tag, const Output_data* od)
{ this->add_entry(Dynamic_entry(tag, od, true)); }
// Add a new dynamic entry with the total size of two output datas.
void
add_section_size(elfcpp::DT tag, const Output_data* od,
const Output_data* od2)
{ this->add_entry(Dynamic_entry(tag, od, od2)); }
// Add a new dynamic entry with the address of a symbol.
void
add_symbol(elfcpp::DT tag, const Symbol* sym)
{ this->add_entry(Dynamic_entry(tag, sym)); }
// Add a new dynamic entry with a string.
void
add_string(elfcpp::DT tag, const char* str)
{ this->add_entry(Dynamic_entry(tag, this->pool_->add(str, true, NULL))); }
void
add_string(elfcpp::DT tag, const std::string& str)
{ this->add_string(tag, str.c_str()); }
protected:
// Adjust the output section to set the entry size.
void
do_adjust_output_section(Output_section*);
// Set the final data size.
void
set_final_data_size();
// Write out the dynamic entries.
void
do_write(Output_file*);
// Write to a map file.
void
do_print_to_mapfile(Mapfile* mapfile) const
{ mapfile->print_output_data(this, _("** dynamic")); }
private:
// This POD class holds a single dynamic entry.
class Dynamic_entry
{
public:
// Create an entry with a fixed numeric value.
Dynamic_entry(elfcpp::DT tag, unsigned int val)
: tag_(tag), offset_(DYNAMIC_NUMBER)
{ this->u_.val = val; }
// Create an entry with the size or address of a section.
Dynamic_entry(elfcpp::DT tag, const Output_data* od, bool section_size)
: tag_(tag),
offset_(section_size
? DYNAMIC_SECTION_SIZE
: DYNAMIC_SECTION_ADDRESS)
{
this->u_.od = od;
this->od2 = NULL;
}
// Create an entry with the size of two sections.
Dynamic_entry(elfcpp::DT tag, const Output_data* od, const Output_data* od2)
: tag_(tag),
offset_(DYNAMIC_SECTION_SIZE)
{
this->u_.od = od;
this->od2 = od2;
}
// Create an entry with the address of a section plus a constant offset.
Dynamic_entry(elfcpp::DT tag, const Output_data* od, unsigned int offset)
: tag_(tag),
offset_(offset)
{ this->u_.od = od; }
// Create an entry with the address of a symbol.
Dynamic_entry(elfcpp::DT tag, const Symbol* sym)
: tag_(tag), offset_(DYNAMIC_SYMBOL)
{ this->u_.sym = sym; }
// Create an entry with a string.
Dynamic_entry(elfcpp::DT tag, const char* str)
: tag_(tag), offset_(DYNAMIC_STRING)
{ this->u_.str = str; }
// Return the tag of this entry.
elfcpp::DT
tag() const
{ return this->tag_; }
// Write the dynamic entry to an output view.
template<int size, bool big_endian>
void
write(unsigned char* pov, const Stringpool*) const;
private:
// Classification is encoded in the OFFSET field.
enum Classification
{
// Section address.
DYNAMIC_SECTION_ADDRESS = 0,
// Number.
DYNAMIC_NUMBER = -1U,
// Section size.
DYNAMIC_SECTION_SIZE = -2U,
// Symbol adress.
DYNAMIC_SYMBOL = -3U,
// String.
DYNAMIC_STRING = -4U
// Any other value indicates a section address plus OFFSET.
};
union
{
// For DYNAMIC_NUMBER.
unsigned int val;
// For DYNAMIC_SECTION_SIZE and section address plus OFFSET.
const Output_data* od;
// For DYNAMIC_SYMBOL.
const Symbol* sym;
// For DYNAMIC_STRING.
const char* str;
} u_;
// For DYNAMIC_SYMBOL with two sections.
const Output_data* od2;
// The dynamic tag.
elfcpp::DT tag_;
// The type of entry (Classification) or offset within a section.
unsigned int offset_;
};
// Add an entry to the list.
void
add_entry(const Dynamic_entry& entry)
{ this->entries_.push_back(entry); }
// Sized version of write function.
template<int size, bool big_endian>
void
sized_write(Output_file* of);
// The type of the list of entries.
typedef std::vector<Dynamic_entry> Dynamic_entries;
// The entries.
Dynamic_entries entries_;
// The pool used for strings.
Stringpool* pool_;
};
// Output_symtab_xindex is used to handle SHT_SYMTAB_SHNDX sections,
// which may be required if the object file has more than
// SHN_LORESERVE sections.
class Output_symtab_xindex : public Output_section_data
{
public:
Output_symtab_xindex(size_t symcount)
: Output_section_data(symcount * 4, 4, true),
entries_()
{ }
// Add an entry: symbol number SYMNDX has section SHNDX.
void
add(unsigned int symndx, unsigned int shndx)
{ this->entries_.push_back(std::make_pair(symndx, shndx)); }
protected:
void
do_write(Output_file*);
// Write to a map file.
void
do_print_to_mapfile(Mapfile* mapfile) const
{ mapfile->print_output_data(this, _("** symtab xindex")); }
private:
template<bool big_endian>
void
endian_do_write(unsigned char*);
// It is likely that most symbols will not require entries. Rather
// than keep a vector for all symbols, we keep pairs of symbol index
// and section index.
typedef std::vector<std::pair<unsigned int, unsigned int> > Xindex_entries;
// The entries we need.
Xindex_entries entries_;
};
// A relaxed input section.
class Output_relaxed_input_section : public Output_section_data_build
{
public:
// We would like to call relobj->section_addralign(shndx) to get the
// alignment but we do not want the constructor to fail. So callers
// are repsonsible for ensuring that.
Output_relaxed_input_section(Relobj* relobj, unsigned int shndx,
uint64_t addralign)
: Output_section_data_build(addralign), relobj_(relobj), shndx_(shndx)
{ }
// Return the Relobj of this relaxed input section.
Relobj*
relobj() const
{ return this->relobj_; }
// Return the section index of this relaxed input section.
unsigned int
shndx() const
{ return this->shndx_; }
protected:
void
set_relobj(Relobj* relobj)
{ this->relobj_ = relobj; }
void
set_shndx(unsigned int shndx)
{ this->shndx_ = shndx; }
private:
Relobj* relobj_;
unsigned int shndx_;
};
// This class describes properties of merge data sections. It is used
// as a key type for maps.
class Merge_section_properties
{
public:
Merge_section_properties(bool is_string, uint64_t entsize,
uint64_t addralign)
: is_string_(is_string), entsize_(entsize), addralign_(addralign)
{ }
// Whether this equals to another Merge_section_properties MSP.
bool
eq(const Merge_section_properties& msp) const
{
return ((this->is_string_ == msp.is_string_)
&& (this->entsize_ == msp.entsize_)
&& (this->addralign_ == msp.addralign_));
}
// Compute a hash value for this using 64-bit FNV-1a hash.
size_t
hash_value() const
{
uint64_t h = 14695981039346656037ULL; // FNV offset basis.
uint64_t prime = 1099511628211ULL;
h = (h ^ static_cast<uint64_t>(this->is_string_)) * prime;
h = (h ^ static_cast<uint64_t>(this->entsize_)) * prime;
h = (h ^ static_cast<uint64_t>(this->addralign_)) * prime;
return h;
}
// Functors for associative containers.
struct equal_to
{
bool
operator()(const Merge_section_properties& msp1,
const Merge_section_properties& msp2) const
{ return msp1.eq(msp2); }
};
struct hash
{
size_t
operator()(const Merge_section_properties& msp) const
{ return msp.hash_value(); }
};
private:
// Whether this merge data section is for strings.
bool is_string_;
// Entsize of this merge data section.
uint64_t entsize_;
// Address alignment.
uint64_t addralign_;
};
// This class is used to speed up look up of special input sections in an
// Output_section.
class Output_section_lookup_maps
{
public:
Output_section_lookup_maps()
: is_valid_(true), merge_sections_by_properties_(),
merge_sections_by_id_(), relaxed_input_sections_by_id_()
{ }
// Whether the maps are valid.
bool
is_valid() const
{ return this->is_valid_; }
// Invalidate the maps.
void
invalidate()
{ this->is_valid_ = false; }
// Clear the maps.
void
clear()
{
this->merge_sections_by_properties_.clear();
this->merge_sections_by_id_.clear();
this->relaxed_input_sections_by_id_.clear();
// A cleared map is valid.
this->is_valid_ = true;
}
// Find a merge section by merge section properties. Return NULL if none
// is found.
Output_merge_base*
find_merge_section(const Merge_section_properties& msp) const
{
gold_assert(this->is_valid_);
Merge_sections_by_properties::const_iterator p =
this->merge_sections_by_properties_.find(msp);
return p != this->merge_sections_by_properties_.end() ? p->second : NULL;
}
// Find a merge section by section ID of a merge input section. Return NULL
// if none is found.
Output_merge_base*
find_merge_section(const Object* object, unsigned int shndx) const
{
gold_assert(this->is_valid_);
Merge_sections_by_id::const_iterator p =
this->merge_sections_by_id_.find(Const_section_id(object, shndx));
return p != this->merge_sections_by_id_.end() ? p->second : NULL;
}
// Add a merge section pointed by POMB with properties MSP.
void
add_merge_section(const Merge_section_properties& msp,
Output_merge_base* pomb)
{
std::pair<Merge_section_properties, Output_merge_base*> value(msp, pomb);
std::pair<Merge_sections_by_properties::iterator, bool> result =
this->merge_sections_by_properties_.insert(value);
gold_assert(result.second);
}
// Add a mapping from a merged input section in OBJECT with index SHNDX
// to a merge output section pointed by POMB.
void
add_merge_input_section(const Object* object, unsigned int shndx,
Output_merge_base* pomb)
{
Const_section_id csid(object, shndx);
std::pair<Const_section_id, Output_merge_base*> value(csid, pomb);
std::pair<Merge_sections_by_id::iterator, bool> result =
this->merge_sections_by_id_.insert(value);
gold_assert(result.second);
}
// Find a relaxed input section of OBJECT with index SHNDX.
Output_relaxed_input_section*
find_relaxed_input_section(const Object* object, unsigned int shndx) const
{
gold_assert(this->is_valid_);
Relaxed_input_sections_by_id::const_iterator p =
this->relaxed_input_sections_by_id_.find(Const_section_id(object, shndx));
return p != this->relaxed_input_sections_by_id_.end() ? p->second : NULL;
}
// Add a relaxed input section pointed by POMB and whose original input
// section is in OBJECT with index SHNDX.
void
add_relaxed_input_section(const Relobj* relobj, unsigned int shndx,
Output_relaxed_input_section* poris)
{
Const_section_id csid(relobj, shndx);
std::pair<Const_section_id, Output_relaxed_input_section*>
value(csid, poris);
std::pair<Relaxed_input_sections_by_id::iterator, bool> result =
this->relaxed_input_sections_by_id_.insert(value);
gold_assert(result.second);
}
private:
typedef Unordered_map<Const_section_id, Output_merge_base*,
Const_section_id_hash>
Merge_sections_by_id;
typedef Unordered_map<Merge_section_properties, Output_merge_base*,
Merge_section_properties::hash,
Merge_section_properties::equal_to>
Merge_sections_by_properties;
typedef Unordered_map<Const_section_id, Output_relaxed_input_section*,
Const_section_id_hash>
Relaxed_input_sections_by_id;
// Whether this is valid
bool is_valid_;
// Merge sections by merge section properties.
Merge_sections_by_properties merge_sections_by_properties_;
// Merge sections by section IDs.
Merge_sections_by_id merge_sections_by_id_;
// Relaxed sections by section IDs.
Relaxed_input_sections_by_id relaxed_input_sections_by_id_;
};
// This abstract base class defines the interface for the
// types of methods used to fill free space left in an output
// section during an incremental link. These methods are used
// to insert dummy compilation units into debug info so that
// debug info consumers can scan the debug info serially.
class Output_fill
{
public:
Output_fill()
: is_big_endian_(parameters->target().is_big_endian())
{ }
virtual
~Output_fill()
{ }
// Return the smallest size chunk of free space that can be
// filled with a dummy compilation unit.
size_t
minimum_hole_size() const
{ return this->do_minimum_hole_size(); }
// Write a fill pattern of length LEN at offset OFF in the file.
void
write(Output_file* of, off_t off, size_t len) const
{ this->do_write(of, off, len); }
protected:
virtual size_t
do_minimum_hole_size() const = 0;
virtual void
do_write(Output_file* of, off_t off, size_t len) const = 0;
bool
is_big_endian() const
{ return this->is_big_endian_; }
private:
bool is_big_endian_;
};
// Fill method that introduces a dummy compilation unit in
// a .debug_info or .debug_types section.
class Output_fill_debug_info : public Output_fill
{
public:
Output_fill_debug_info(bool is_debug_types)
: is_debug_types_(is_debug_types)
{ }
protected:
virtual size_t
do_minimum_hole_size() const;
virtual void
do_write(Output_file* of, off_t off, size_t len) const;
private:
// Version of the header.
static const int version = 4;
// True if this is a .debug_types section.
bool is_debug_types_;
};
// Fill method that introduces a dummy compilation unit in
// a .debug_line section.
class Output_fill_debug_line : public Output_fill
{
public:
Output_fill_debug_line()
{ }
protected:
virtual size_t
do_minimum_hole_size() const;
virtual void
do_write(Output_file* of, off_t off, size_t len) const;
private:
// Version of the header. We write a DWARF-3 header because it's smaller
// and many tools have not yet been updated to understand the DWARF-4 header.
static const int version = 3;
// Length of the portion of the header that follows the header_length
// field. This includes the following fields:
// minimum_instruction_length, default_is_stmt, line_base, line_range,
// opcode_base, standard_opcode_lengths[], include_directories, filenames.
// The standard_opcode_lengths array is 12 bytes long, and the
// include_directories and filenames fields each contain only a single
// null byte.
static const size_t header_length = 19;
};
// An output section. We don't expect to have too many output
// sections, so we don't bother to do a template on the size.
class Output_section : public Output_data
{
public:
// Create an output section, giving the name, type, and flags.
Output_section(const char* name, elfcpp::Elf_Word, elfcpp::Elf_Xword);
virtual ~Output_section();
// Add a new input section SHNDX, named NAME, with header SHDR, from
// object OBJECT. RELOC_SHNDX is the index of a relocation section
// which applies to this section, or 0 if none, or -1 if more than
// one. HAVE_SECTIONS_SCRIPT is true if we have a SECTIONS clause
// in a linker script; in that case we need to keep track of input
// sections associated with an output section. Return the offset
// within the output section.
template<int size, bool big_endian>
off_t
add_input_section(Layout* layout, Sized_relobj_file<size, big_endian>* object,
unsigned int shndx, const char* name,
const elfcpp::Shdr<size, big_endian>& shdr,
unsigned int reloc_shndx, bool have_sections_script);
// Add generated data POSD to this output section.
void
add_output_section_data(Output_section_data* posd);
// Add a relaxed input section PORIS called NAME to this output section
// with LAYOUT.
void
add_relaxed_input_section(Layout* layout,
Output_relaxed_input_section* poris,
const std::string& name);
// Return the section name.
const char*
name() const
{ return this->name_; }
// Return the section type.
elfcpp::Elf_Word
type() const
{ return this->type_; }
// Return the section flags.
elfcpp::Elf_Xword
flags() const
{ return this->flags_; }
typedef std::map<Section_id, unsigned int> Section_layout_order;
void
update_section_layout(const Section_layout_order* order_map);
// Update the output section flags based on input section flags.
void
update_flags_for_input_section(elfcpp::Elf_Xword flags);
// Return the entsize field.
uint64_t
entsize() const
{ return this->entsize_; }
// Set the entsize field.
void
set_entsize(uint64_t v);
// Set the load address.
void
set_load_address(uint64_t load_address)
{
this->load_address_ = load_address;
this->has_load_address_ = true;
}
// Set the link field to the output section index of a section.
void
set_link_section(const Output_data* od)
{
gold_assert(this->link_ == 0
&& !this->should_link_to_symtab_
&& !this->should_link_to_dynsym_);
this->link_section_ = od;
}
// Set the link field to a constant.
void
set_link(unsigned int v)
{
gold_assert(this->link_section_ == NULL
&& !this->should_link_to_symtab_
&& !this->should_link_to_dynsym_);
this->link_ = v;
}
// Record that this section should link to the normal symbol table.
void
set_should_link_to_symtab()
{
gold_assert(this->link_section_ == NULL
&& this->link_ == 0
&& !this->should_link_to_dynsym_);
this->should_link_to_symtab_ = true;
}
// Record that this section should link to the dynamic symbol table.
void
set_should_link_to_dynsym()
{
gold_assert(this->link_section_ == NULL
&& this->link_ == 0
&& !this->should_link_to_symtab_);
this->should_link_to_dynsym_ = true;
}
// Return the info field.
unsigned int
info() const
{
gold_assert(this->info_section_ == NULL
&& this->info_symndx_ == NULL);
return this->info_;
}
// Set the info field to the output section index of a section.
void
set_info_section(const Output_section* os)
{
gold_assert((this->info_section_ == NULL
|| (this->info_section_ == os
&& this->info_uses_section_index_))
&& this->info_symndx_ == NULL
&& this->info_ == 0);
this->info_section_ = os;
this->info_uses_section_index_= true;
}
// Set the info field to the symbol table index of a symbol.
void
set_info_symndx(const Symbol* sym)
{
gold_assert(this->info_section_ == NULL
&& (this->info_symndx_ == NULL
|| this->info_symndx_ == sym)
&& this->info_ == 0);
this->info_symndx_ = sym;
}
// Set the info field to the symbol table index of a section symbol.
void
set_info_section_symndx(const Output_section* os)
{
gold_assert((this->info_section_ == NULL
|| (this->info_section_ == os
&& !this->info_uses_section_index_))
&& this->info_symndx_ == NULL
&& this->info_ == 0);
this->info_section_ = os;
this->info_uses_section_index_ = false;
}
// Set the info field to a constant.
void
set_info(unsigned int v)
{
gold_assert(this->info_section_ == NULL
&& this->info_symndx_ == NULL
&& (this->info_ == 0
|| this->info_ == v));
this->info_ = v;
}
// Set the addralign field.
void
set_addralign(uint64_t v)
{ this->addralign_ = v; }
void
checkpoint_set_addralign(uint64_t val)
{
if (this->checkpoint_ != NULL)
this->checkpoint_->set_addralign(val);
}
// Whether the output section index has been set.
bool
has_out_shndx() const
{ return this->out_shndx_ != -1U; }
// Indicate that we need a symtab index.
void
set_needs_symtab_index()
{ this->needs_symtab_index_ = true; }
// Return whether we need a symtab index.
bool
needs_symtab_index() const
{ return this->needs_symtab_index_; }
// Get the symtab index.
unsigned int
symtab_index() const
{
gold_assert(this->symtab_index_ != 0);
return this->symtab_index_;
}
// Set the symtab index.
void
set_symtab_index(unsigned int index)
{
gold_assert(index != 0);
this->symtab_index_ = index;
}
// Indicate that we need a dynsym index.
void
set_needs_dynsym_index()
{ this->needs_dynsym_index_ = true; }
// Return whether we need a dynsym index.
bool
needs_dynsym_index() const
{ return this->needs_dynsym_index_; }
// Get the dynsym index.
unsigned int
dynsym_index() const
{
gold_assert(this->dynsym_index_ != 0);
return this->dynsym_index_;
}
// Set the dynsym index.
void
set_dynsym_index(unsigned int index)
{
gold_assert(index != 0);
this->dynsym_index_ = index;
}
// Sort the attached input sections.
void
sort_attached_input_sections();
// Return whether the input sections sections attachd to this output
// section may require sorting. This is used to handle constructor
// priorities compatibly with GNU ld.
bool
may_sort_attached_input_sections() const
{ return this->may_sort_attached_input_sections_; }
// Record that the input sections attached to this output section
// may require sorting.
void
set_may_sort_attached_input_sections()
{ this->may_sort_attached_input_sections_ = true; }
// Returns true if input sections must be sorted according to the
// order in which their name appear in the --section-ordering-file.
bool
input_section_order_specified()
{ return this->input_section_order_specified_; }
// Record that input sections must be sorted as some of their names
// match the patterns specified through --section-ordering-file.
void
set_input_section_order_specified()
{ this->input_section_order_specified_ = true; }
// Return whether the input sections attached to this output section
// require sorting. This is used to handle constructor priorities
// compatibly with GNU ld.
bool
must_sort_attached_input_sections() const
{ return this->must_sort_attached_input_sections_; }
// Record that the input sections attached to this output section
// require sorting.
void
set_must_sort_attached_input_sections()
{ this->must_sort_attached_input_sections_ = true; }
// Get the order in which this section appears in the PT_LOAD output
// segment.
Output_section_order
order() const
{ return this->order_; }
// Set the order for this section.
void
set_order(Output_section_order order)
{ this->order_ = order; }
// Return whether this section holds relro data--data which has
// dynamic relocations but which may be marked read-only after the
// dynamic relocations have been completed.
bool
is_relro() const
{ return this->is_relro_; }
// Record that this section holds relro data.
void
set_is_relro()
{ this->is_relro_ = true; }
// Record that this section does not hold relro data.
void
clear_is_relro()
{ this->is_relro_ = false; }
// True if this is a small section: a section which holds small
// variables.
bool
is_small_section() const
{ return this->is_small_section_; }
// Record that this is a small section.
void
set_is_small_section()
{ this->is_small_section_ = true; }
// True if this is a large section: a section which holds large
// variables.
bool
is_large_section() const
{ return this->is_large_section_; }
// Record that this is a large section.
void
set_is_large_section()
{ this->is_large_section_ = true; }
// True if this is a large data (not BSS) section.
bool
is_large_data_section()
{ return this->is_large_section_ && this->type_ != elfcpp::SHT_NOBITS; }
// Return whether this section should be written after all the input
// sections are complete.
bool
after_input_sections() const
{ return this->after_input_sections_; }
// Record that this section should be written after all the input
// sections are complete.
void
set_after_input_sections()
{ this->after_input_sections_ = true; }
// Return whether this section requires postprocessing after all
// relocations have been applied.
bool
requires_postprocessing() const
{ return this->requires_postprocessing_; }
bool
is_unique_segment() const
{ return this->is_unique_segment_; }
void
set_is_unique_segment()
{ this->is_unique_segment_ = true; }
uint64_t extra_segment_flags() const
{ return this->extra_segment_flags_; }
void
set_extra_segment_flags(uint64_t flags)
{ this->extra_segment_flags_ = flags; }
uint64_t segment_alignment() const
{ return this->segment_alignment_; }
void
set_segment_alignment(uint64_t align)
{ this->segment_alignment_ = align; }
// If a section requires postprocessing, return the buffer to use.
unsigned char*
postprocessing_buffer() const
{
gold_assert(this->postprocessing_buffer_ != NULL);
return this->postprocessing_buffer_;
}
// If a section requires postprocessing, create the buffer to use.
void
create_postprocessing_buffer();
// If a section requires postprocessing, this is the size of the
// buffer to which relocations should be applied.
off_t
postprocessing_buffer_size() const
{ return this->current_data_size_for_child(); }
// Modify the section name. This is only permitted for an
// unallocated section, and only before the size has been finalized.
// Otherwise the name will not get into Layout::namepool_.
void
set_name(const char* newname)
{
gold_assert((this->flags_ & elfcpp::SHF_ALLOC) == 0);
gold_assert(!this->is_data_size_valid());
this->name_ = newname;
}
// Return whether the offset OFFSET in the input section SHNDX in
// object OBJECT is being included in the link.
bool
is_input_address_mapped(const Relobj* object, unsigned int shndx,
off_t offset) const;
// Return the offset within the output section of OFFSET relative to
// the start of input section SHNDX in object OBJECT.
section_offset_type
output_offset(const Relobj* object, unsigned int shndx,
section_offset_type offset) const;
// Return the output virtual address of OFFSET relative to the start
// of input section SHNDX in object OBJECT.
uint64_t
output_address(const Relobj* object, unsigned int shndx,
off_t offset) const;
// Look for the merged section for input section SHNDX in object
// OBJECT. If found, return true, and set *ADDR to the address of
// the start of the merged section. This is not necessary the
// output offset corresponding to input offset 0 in the section,
// since the section may be mapped arbitrarily.
bool
find_starting_output_address(const Relobj* object, unsigned int shndx,
uint64_t* addr) const;
// Record that this output section was found in the SECTIONS clause
// of a linker script.
void
set_found_in_sections_clause()
{ this->found_in_sections_clause_ = true; }
// Return whether this output section was found in the SECTIONS
// clause of a linker script.
bool
found_in_sections_clause() const
{ return this->found_in_sections_clause_; }
// Write the section header into *OPHDR.
template<int size, bool big_endian>
void
write_header(const Layout*, const Stringpool*,
elfcpp::Shdr_write<size, big_endian>*) const;
// The next few calls are for linker script support.
// In some cases we need to keep a list of the input sections
// associated with this output section. We only need the list if we
// might have to change the offsets of the input section within the
// output section after we add the input section. The ordinary
// input sections will be written out when we process the object
// file, and as such we don't need to track them here. We do need
// to track Output_section_data objects here. We store instances of
// this structure in a std::vector, so it must be a POD. There can
// be many instances of this structure, so we use a union to save
// some space.
class Input_section
{
public:
Input_section()
: shndx_(0), p2align_(0)
{
this->u1_.data_size = 0;
this->u2_.object = NULL;
}
// For an ordinary input section.
Input_section(Relobj* object, unsigned int shndx, off_t data_size,
uint64_t addralign)
: shndx_(shndx),
p2align_(ffsll(static_cast<long long>(addralign))),
section_order_index_(0)
{
gold_assert(shndx != OUTPUT_SECTION_CODE
&& shndx != MERGE_DATA_SECTION_CODE
&& shndx != MERGE_STRING_SECTION_CODE
&& shndx != RELAXED_INPUT_SECTION_CODE);
this->u1_.data_size = data_size;
this->u2_.object = object;
}
// For a non-merge output section.
Input_section(Output_section_data* posd)
: shndx_(OUTPUT_SECTION_CODE), p2align_(0),
section_order_index_(0)
{
this->u1_.data_size = 0;
this->u2_.posd = posd;
}
// For a merge section.
Input_section(Output_section_data* posd, bool is_string, uint64_t entsize)
: shndx_(is_string
? MERGE_STRING_SECTION_CODE
: MERGE_DATA_SECTION_CODE),
p2align_(0),
section_order_index_(0)
{
this->u1_.entsize = entsize;
this->u2_.posd = posd;
}
// For a relaxed input section.
Input_section(Output_relaxed_input_section* psection)
: shndx_(RELAXED_INPUT_SECTION_CODE), p2align_(0),
section_order_index_(0)
{
this->u1_.data_size = 0;
this->u2_.poris = psection;
}
unsigned int
section_order_index() const
{
return this->section_order_index_;
}
void
set_section_order_index(unsigned int number)
{
this->section_order_index_ = number;
}
// The required alignment.
uint64_t
addralign() const
{
if (this->p2align_ != 0)
return static_cast<uint64_t>(1) << (this->p2align_ - 1);
else if (!this->is_input_section())
return this->u2_.posd->addralign();
else
return 0;
}
// Set the required alignment, which must be either 0 or a power of 2.
// For input sections that are sub-classes of Output_section_data, a
// alignment of zero means asking the underlying object for alignment.
void
set_addralign(uint64_t addralign)
{
if (addralign == 0)
this->p2align_ = 0;
else
{
gold_assert((addralign & (addralign - 1)) == 0);
this->p2align_ = ffsll(static_cast<long long>(addralign));
}
}
// Return the current required size, without finalization.
off_t
current_data_size() const;
// Return the required size.
off_t
data_size() const;
// Whether this is an input section.
bool
is_input_section() const
{
return (this->shndx_ != OUTPUT_SECTION_CODE
&& this->shndx_ != MERGE_DATA_SECTION_CODE
&& this->shndx_ != MERGE_STRING_SECTION_CODE
&& this->shndx_ != RELAXED_INPUT_SECTION_CODE);
}
// Return whether this is a merge section which matches the
// parameters.
bool
is_merge_section(bool is_string, uint64_t entsize,
uint64_t addralign) const
{
return (this->shndx_ == (is_string
? MERGE_STRING_SECTION_CODE
: MERGE_DATA_SECTION_CODE)
&& this->u1_.entsize == entsize
&& this->addralign() == addralign);
}
// Return whether this is a merge section for some input section.
bool
is_merge_section() const
{
return (this->shndx_ == MERGE_DATA_SECTION_CODE
|| this->shndx_ == MERGE_STRING_SECTION_CODE);
}
// Return whether this is a relaxed input section.
bool
is_relaxed_input_section() const
{ return this->shndx_ == RELAXED_INPUT_SECTION_CODE; }
// Return whether this is a generic Output_section_data.
bool
is_output_section_data() const
{
return this->shndx_ == OUTPUT_SECTION_CODE;
}
// Return the object for an input section.
Relobj*
relobj() const;
// Return the input section index for an input section.
unsigned int
shndx() const;
// For non-input-sections, return the associated Output_section_data
// object.
Output_section_data*
output_section_data() const
{
gold_assert(!this->is_input_section());
return this->u2_.posd;
}
// For a merge section, return the Output_merge_base pointer.
Output_merge_base*
output_merge_base() const
{
gold_assert(this->is_merge_section());
return this->u2_.pomb;
}
// Return the Output_relaxed_input_section object.
Output_relaxed_input_section*
relaxed_input_section() const
{
gold_assert(this->is_relaxed_input_section());
return this->u2_.poris;
}
// Set the output section.
void
set_output_section(Output_section* os)
{
gold_assert(!this->is_input_section());
Output_section_data* posd =
this->is_relaxed_input_section() ? this->u2_.poris : this->u2_.posd;
posd->set_output_section(os);
}
// Set the address and file offset. This is called during
// Layout::finalize. SECTION_FILE_OFFSET is the file offset of
// the enclosing section.
void
set_address_and_file_offset(uint64_t address, off_t file_offset,
off_t section_file_offset);
// Reset the address and file offset.
void
reset_address_and_file_offset();
// Finalize the data size.
void
finalize_data_size();
// Add an input section, for SHF_MERGE sections.
bool
add_input_section(Relobj* object, unsigned int shndx)
{
gold_assert(this->shndx_ == MERGE_DATA_SECTION_CODE
|| this->shndx_ == MERGE_STRING_SECTION_CODE);
return this->u2_.posd->add_input_section(object, shndx);
}
// Given an input OBJECT, an input section index SHNDX within that
// object, and an OFFSET relative to the start of that input
// section, return whether or not the output offset is known. If
// this function returns true, it sets *POUTPUT to the offset in
// the output section, relative to the start of the input section
// in the output section. *POUTPUT may be different from OFFSET
// for a merged section.
bool
output_offset(const Relobj* object, unsigned int shndx,
section_offset_type offset,
section_offset_type* poutput) const;
// Return whether this is the merge section for the input section
// SHNDX in OBJECT.
bool
is_merge_section_for(const Relobj* object, unsigned int shndx) const;
// Write out the data. This does nothing for an input section.
void
write(Output_file*);
// Write the data to a buffer. This does nothing for an input
// section.
void
write_to_buffer(unsigned char*);
// Print to a map file.
void
print_to_mapfile(Mapfile*) const;
// Print statistics about merge sections to stderr.
void
print_merge_stats(const char* section_name)
{
if (this->shndx_ == MERGE_DATA_SECTION_CODE
|| this->shndx_ == MERGE_STRING_SECTION_CODE)
this->u2_.posd->print_merge_stats(section_name);
}
private:
// Code values which appear in shndx_. If the value is not one of
// these codes, it is the input section index in the object file.
enum
{
// An Output_section_data.
OUTPUT_SECTION_CODE = -1U,
// An Output_section_data for an SHF_MERGE section with
// SHF_STRINGS not set.
MERGE_DATA_SECTION_CODE = -2U,
// An Output_section_data for an SHF_MERGE section with
// SHF_STRINGS set.
MERGE_STRING_SECTION_CODE = -3U,
// An Output_section_data for a relaxed input section.
RELAXED_INPUT_SECTION_CODE = -4U
};
// For an ordinary input section, this is the section index in the
// input file. For an Output_section_data, this is
// OUTPUT_SECTION_CODE or MERGE_DATA_SECTION_CODE or
// MERGE_STRING_SECTION_CODE.
unsigned int shndx_;
// The required alignment, stored as a power of 2.
unsigned int p2align_;
union
{
// For an ordinary input section, the section size.
off_t data_size;
// For OUTPUT_SECTION_CODE or RELAXED_INPUT_SECTION_CODE, this is not
// used. For MERGE_DATA_SECTION_CODE or MERGE_STRING_SECTION_CODE, the
// entity size.
uint64_t entsize;
} u1_;
union
{
// For an ordinary input section, the object which holds the
// input section.
Relobj* object;
// For OUTPUT_SECTION_CODE or MERGE_DATA_SECTION_CODE or
// MERGE_STRING_SECTION_CODE, the data.
Output_section_data* posd;
Output_merge_base* pomb;
// For RELAXED_INPUT_SECTION_CODE, the data.
Output_relaxed_input_section* poris;
} u2_;
// The line number of the pattern it matches in the --section-ordering-file
// file. It is 0 if does not match any pattern.
unsigned int section_order_index_;
};
// Store the list of input sections for this Output_section into the
// list passed in. This removes the input sections, leaving only
// any Output_section_data elements. This returns the size of those
// Output_section_data elements. ADDRESS is the address of this
// output section. FILL is the fill value to use, in case there are
// any spaces between the remaining Output_section_data elements.
uint64_t
get_input_sections(uint64_t address, const std::string& fill,
std::list<Input_section>*);
// Add a script input section. A script input section can either be
// a plain input section or a sub-class of Output_section_data.
void
add_script_input_section(const Input_section& input_section);
// Set the current size of the output section.
void
set_current_data_size(off_t size)
{ this->set_current_data_size_for_child(size); }
// End of linker script support.
// Save states before doing section layout.
// This is used for relaxation.
void
save_states();
// Restore states prior to section layout.
void
restore_states();
// Discard states.
void
discard_states();
// Convert existing input sections to relaxed input sections.
void
convert_input_sections_to_relaxed_sections(
const std::vector<Output_relaxed_input_section*>& sections);
// Find a relaxed input section to an input section in OBJECT
// with index SHNDX. Return NULL if none is found.
const Output_relaxed_input_section*
find_relaxed_input_section(const Relobj* object, unsigned int shndx) const;
// Whether section offsets need adjustment due to relaxation.
bool
section_offsets_need_adjustment() const
{ return this->section_offsets_need_adjustment_; }
// Set section_offsets_need_adjustment to be true.
void
set_section_offsets_need_adjustment()
{ this->section_offsets_need_adjustment_ = true; }
// Set section_offsets_need_adjustment to be false.
void
clear_section_offsets_need_adjustment()
{ this->section_offsets_need_adjustment_ = false; }
// Adjust section offsets of input sections in this. This is
// requires if relaxation caused some input sections to change sizes.
void
adjust_section_offsets();
// Whether this is a NOLOAD section.
bool
is_noload() const
{ return this->is_noload_; }
// Set NOLOAD flag.
void
set_is_noload()
{ this->is_noload_ = true; }
// Print merge statistics to stderr.
void
print_merge_stats();
// Set a fixed layout for the section. Used for incremental update links.
void
set_fixed_layout(uint64_t sh_addr, off_t sh_offset, off_t sh_size,
uint64_t sh_addralign);
// Return TRUE if the section has a fixed layout.
bool
has_fixed_layout() const
{ return this->has_fixed_layout_; }
// Set flag to allow patch space for this section. Used for full
// incremental links.
void
set_is_patch_space_allowed()
{ this->is_patch_space_allowed_ = true; }
// Set a fill method to use for free space left in the output section
// during incremental links.
void
set_free_space_fill(Output_fill* free_space_fill)
{
this->free_space_fill_ = free_space_fill;
this->free_list_.set_min_hole_size(free_space_fill->minimum_hole_size());
}
// Reserve space within the fixed layout for the section. Used for
// incremental update links.
void
reserve(uint64_t sh_offset, uint64_t sh_size);
// Allocate space from the free list for the section. Used for
// incremental update links.
off_t
allocate(off_t len, uint64_t addralign);
typedef std::vector<Input_section> Input_section_list;
// Allow access to the input sections.
const Input_section_list&
input_sections() const
{ return this->input_sections_; }
Input_section_list&
input_sections()
{ return this->input_sections_; }
protected:
// Return the output section--i.e., the object itself.
Output_section*
do_output_section()
{ return this; }
const Output_section*
do_output_section() const
{ return this; }
// Return the section index in the output file.
unsigned int
do_out_shndx() const
{
gold_assert(this->out_shndx_ != -1U);
return this->out_shndx_;
}
// Set the output section index.
void
do_set_out_shndx(unsigned int shndx)
{
gold_assert(this->out_shndx_ == -1U || this->out_shndx_ == shndx);
this->out_shndx_ = shndx;
}
// Update the data size of the Output_section. For a typical
// Output_section, there is nothing to do, but if there are any
// Output_section_data objects we need to do a trial layout
// here.
virtual void
update_data_size();
// Set the final data size of the Output_section. For a typical
// Output_section, there is nothing to do, but if there are any
// Output_section_data objects we need to set their final addresses
// here.
virtual void
set_final_data_size();
// Reset the address and file offset.
void
do_reset_address_and_file_offset();
// Return true if address and file offset already have reset values. In
// other words, calling reset_address_and_file_offset will not change them.
bool
do_address_and_file_offset_have_reset_values() const;
// Write the data to the file. For a typical Output_section, this
// does nothing: the data is written out by calling Object::Relocate
// on each input object. But if there are any Output_section_data
// objects we do need to write them out here.
virtual void
do_write(Output_file*);
// Return the address alignment--function required by parent class.
uint64_t
do_addralign() const
{ return this->addralign_; }
// Return whether there is a load address.
bool
do_has_load_address() const
{ return this->has_load_address_; }
// Return the load address.
uint64_t
do_load_address() const
{
gold_assert(this->has_load_address_);
return this->load_address_;
}
// Return whether this is an Output_section.
bool
do_is_section() const
{ return true; }
// Return whether this is a section of the specified type.
bool
do_is_section_type(elfcpp::Elf_Word type) const
{ return this->type_ == type; }
// Return whether the specified section flag is set.
bool
do_is_section_flag_set(elfcpp::Elf_Xword flag) const
{ return (this->flags_ & flag) != 0; }
// Set the TLS offset. Called only for SHT_TLS sections.
void
do_set_tls_offset(uint64_t tls_base);
// Return the TLS offset, relative to the base of the TLS segment.
// Valid only for SHT_TLS sections.
uint64_t
do_tls_offset() const
{ return this->tls_offset_; }
// This may be implemented by a child class.
virtual void
do_finalize_name(Layout*)
{ }
// Print to the map file.
virtual void
do_print_to_mapfile(Mapfile*) const;
// Record that this section requires postprocessing after all
// relocations have been applied. This is called by a child class.
void
set_requires_postprocessing()
{
this->requires_postprocessing_ = true;
this->after_input_sections_ = true;
}
// Write all the data of an Output_section into the postprocessing
// buffer.
void
write_to_postprocessing_buffer();
// Whether this always keeps an input section list
bool
always_keeps_input_sections() const
{ return this->always_keeps_input_sections_; }
// Always keep an input section list.
void
set_always_keeps_input_sections()
{
gold_assert(this->current_data_size_for_child() == 0);
this->always_keeps_input_sections_ = true;
}
private:
// We only save enough information to undo the effects of section layout.
class Checkpoint_output_section
{
public:
Checkpoint_output_section(uint64_t addralign, elfcpp::Elf_Xword flags,
const Input_section_list& input_sections,
off_t first_input_offset,
bool attached_input_sections_are_sorted)
: addralign_(addralign), flags_(flags),
input_sections_(input_sections),
input_sections_size_(input_sections_.size()),
input_sections_copy_(), first_input_offset_(first_input_offset),
attached_input_sections_are_sorted_(attached_input_sections_are_sorted)
{ }
virtual
~Checkpoint_output_section()
{ }
// Return the address alignment.
uint64_t
addralign() const
{ return this->addralign_; }
void
set_addralign(uint64_t val)
{ this->addralign_ = val; }
// Return the section flags.
elfcpp::Elf_Xword
flags() const
{ return this->flags_; }
// Return a reference to the input section list copy.
Input_section_list*
input_sections()
{ return &this->input_sections_copy_; }
// Return the size of input_sections at the time when checkpoint is
// taken.
size_t
input_sections_size() const
{ return this->input_sections_size_; }
// Whether input sections are copied.
bool
input_sections_saved() const
{ return this->input_sections_copy_.size() == this->input_sections_size_; }
off_t
first_input_offset() const
{ return this->first_input_offset_; }
bool
attached_input_sections_are_sorted() const
{ return this->attached_input_sections_are_sorted_; }
// Save input sections.
void
save_input_sections()
{
this->input_sections_copy_.reserve(this->input_sections_size_);
this->input_sections_copy_.clear();
Input_section_list::const_iterator p = this->input_sections_.begin();
gold_assert(this->input_sections_size_ >= this->input_sections_.size());
for(size_t i = 0; i < this->input_sections_size_ ; i++, ++p)
this->input_sections_copy_.push_back(*p);
}
private:
// The section alignment.
uint64_t addralign_;
// The section flags.
elfcpp::Elf_Xword flags_;
// Reference to the input sections to be checkpointed.
const Input_section_list& input_sections_;
// Size of the checkpointed portion of input_sections_;
size_t input_sections_size_;
// Copy of input sections.
Input_section_list input_sections_copy_;
// The offset of the first entry in input_sections_.
off_t first_input_offset_;
// True if the input sections attached to this output section have
// already been sorted.
bool attached_input_sections_are_sorted_;
};
// This class is used to sort the input sections.
class Input_section_sort_entry;
// This is the sort comparison function for ctors and dtors.
struct Input_section_sort_compare
{
bool
operator()(const Input_section_sort_entry&,
const Input_section_sort_entry&) const;
};
// This is the sort comparison function for .init_array and .fini_array.
struct Input_section_sort_init_fini_compare
{
bool
operator()(const Input_section_sort_entry&,
const Input_section_sort_entry&) const;
};
// This is the sort comparison function when a section order is specified
// from an input file.
struct Input_section_sort_section_order_index_compare
{
bool
operator()(const Input_section_sort_entry&,
const Input_section_sort_entry&) const;
};
// This is the sort comparison function for .text to sort sections with
// prefixes .text.{unlikely,exit,startup,hot} before other sections.
struct Input_section_sort_section_name_special_ordering_compare
{
bool
operator()(const Input_section_sort_entry&,
const Input_section_sort_entry&) const;
};
// Fill data. This is used to fill in data between input sections.
// It is also used for data statements (BYTE, WORD, etc.) in linker
// scripts. When we have to keep track of the input sections, we
// can use an Output_data_const, but we don't want to have to keep
// track of input sections just to implement fills.
class Fill
{
public:
Fill(off_t section_offset, off_t length)
: section_offset_(section_offset),
length_(convert_to_section_size_type(length))
{ }
// Return section offset.
off_t
section_offset() const
{ return this->section_offset_; }
// Return fill length.
section_size_type
length() const
{ return this->length_; }
private:
// The offset within the output section.
off_t section_offset_;
// The length of the space to fill.
section_size_type length_;
};
typedef std::vector<Fill> Fill_list;
// Map used during relaxation of existing sections. This map
// a section id an input section list index. We assume that
// Input_section_list is a vector.
typedef Unordered_map<Section_id, size_t, Section_id_hash> Relaxation_map;
// Add a new output section by Input_section.
void
add_output_section_data(Input_section*);
// Add an SHF_MERGE input section. Returns true if the section was
// handled. If KEEPS_INPUT_SECTIONS is true, the output merge section
// stores information about the merged input sections.
bool
add_merge_input_section(Relobj* object, unsigned int shndx, uint64_t flags,
uint64_t entsize, uint64_t addralign,
bool keeps_input_sections);
// Add an output SHF_MERGE section POSD to this output section.
// IS_STRING indicates whether it is a SHF_STRINGS section, and
// ENTSIZE is the entity size. This returns the entry added to
// input_sections_.
void
add_output_merge_section(Output_section_data* posd, bool is_string,
uint64_t entsize);
// Find the merge section into which an input section with index SHNDX in
// OBJECT has been added. Return NULL if none found.
Output_section_data*
find_merge_section(const Relobj* object, unsigned int shndx) const;
// Build a relaxation map.
void
build_relaxation_map(
const Input_section_list& input_sections,
size_t limit,
Relaxation_map* map) const;
// Convert input sections in an input section list into relaxed sections.
void
convert_input_sections_in_list_to_relaxed_sections(
const std::vector<Output_relaxed_input_section*>& relaxed_sections,
const Relaxation_map& map,
Input_section_list* input_sections);
// Build the lookup maps for merge and relaxed input sections.
void
build_lookup_maps() const;
// Most of these fields are only valid after layout.
// The name of the section. This will point into a Stringpool.
const char* name_;
// The section address is in the parent class.
// The section alignment.
uint64_t addralign_;
// The section entry size.
uint64_t entsize_;
// The load address. This is only used when using a linker script
// with a SECTIONS clause. The has_load_address_ field indicates
// whether this field is valid.
uint64_t load_address_;
// The file offset is in the parent class.
// Set the section link field to the index of this section.
const Output_data* link_section_;
// If link_section_ is NULL, this is the link field.
unsigned int link_;
// Set the section info field to the index of this section.
const Output_section* info_section_;
// If info_section_ is NULL, set the info field to the symbol table
// index of this symbol.
const Symbol* info_symndx_;
// If info_section_ and info_symndx_ are NULL, this is the section
// info field.
unsigned int info_;
// The section type.
const elfcpp::Elf_Word type_;
// The section flags.
elfcpp::Elf_Xword flags_;
// The order of this section in the output segment.
Output_section_order order_;
// The section index.
unsigned int out_shndx_;
// If there is a STT_SECTION for this output section in the normal
// symbol table, this is the symbol index. This starts out as zero.
// It is initialized in Layout::finalize() to be the index, or -1U
// if there isn't one.
unsigned int symtab_index_;
// If there is a STT_SECTION for this output section in the dynamic
// symbol table, this is the symbol index. This starts out as zero.
// It is initialized in Layout::finalize() to be the index, or -1U
// if there isn't one.
unsigned int dynsym_index_;
// The input sections. This will be empty in cases where we don't
// need to keep track of them.
Input_section_list input_sections_;
// The offset of the first entry in input_sections_.
off_t first_input_offset_;
// The fill data. This is separate from input_sections_ because we
// often will need fill sections without needing to keep track of
// input sections.
Fill_list fills_;
// If the section requires postprocessing, this buffer holds the
// section contents during relocation.
unsigned char* postprocessing_buffer_;
// Whether this output section needs a STT_SECTION symbol in the
// normal symbol table. This will be true if there is a relocation
// which needs it.
bool needs_symtab_index_ : 1;
// Whether this output section needs a STT_SECTION symbol in the
// dynamic symbol table. This will be true if there is a dynamic
// relocation which needs it.
bool needs_dynsym_index_ : 1;
// Whether the link field of this output section should point to the
// normal symbol table.
bool should_link_to_symtab_ : 1;
// Whether the link field of this output section should point to the
// dynamic symbol table.
bool should_link_to_dynsym_ : 1;
// Whether this section should be written after all the input
// sections are complete.
bool after_input_sections_ : 1;
// Whether this section requires post processing after all
// relocations have been applied.
bool requires_postprocessing_ : 1;
// Whether an input section was mapped to this output section
// because of a SECTIONS clause in a linker script.
bool found_in_sections_clause_ : 1;
// Whether this section has an explicitly specified load address.
bool has_load_address_ : 1;
// True if the info_section_ field means the section index of the
// section, false if it means the symbol index of the corresponding
// section symbol.
bool info_uses_section_index_ : 1;
// True if input sections attached to this output section have to be
// sorted according to a specified order.
bool input_section_order_specified_ : 1;
// True if the input sections attached to this output section may
// need sorting.
bool may_sort_attached_input_sections_ : 1;
// True if the input sections attached to this output section must
// be sorted.
bool must_sort_attached_input_sections_ : 1;
// True if the input sections attached to this output section have
// already been sorted.
bool attached_input_sections_are_sorted_ : 1;
// True if this section holds relro data.
bool is_relro_ : 1;
// True if this is a small section.
bool is_small_section_ : 1;
// True if this is a large section.
bool is_large_section_ : 1;
// Whether code-fills are generated at write.
bool generate_code_fills_at_write_ : 1;
// Whether the entry size field should be zero.
bool is_entsize_zero_ : 1;
// Whether section offsets need adjustment due to relaxation.
bool section_offsets_need_adjustment_ : 1;
// Whether this is a NOLOAD section.
bool is_noload_ : 1;
// Whether this always keeps input section.
bool always_keeps_input_sections_ : 1;
// Whether this section has a fixed layout, for incremental update links.
bool has_fixed_layout_ : 1;
// True if we can add patch space to this section.
bool is_patch_space_allowed_ : 1;
// True if this output section goes into a unique segment.
bool is_unique_segment_ : 1;
// For SHT_TLS sections, the offset of this section relative to the base
// of the TLS segment.
uint64_t tls_offset_;
// Additional segment flags, specified via linker plugin, when mapping some
// input sections to unique segments.
uint64_t extra_segment_flags_;
// Segment alignment specified via linker plugin, when mapping some
// input sections to unique segments.
uint64_t segment_alignment_;
// Saved checkpoint.
Checkpoint_output_section* checkpoint_;
// Fast lookup maps for merged and relaxed input sections.
Output_section_lookup_maps* lookup_maps_;
// List of available regions within the section, for incremental
// update links.
Free_list free_list_;
// Method for filling chunks of free space.
Output_fill* free_space_fill_;
// Amount added as patch space for incremental linking.
off_t patch_space_;
};
// An output segment. PT_LOAD segments are built from collections of
// output sections. Other segments typically point within PT_LOAD
// segments, and are built directly as needed.
//
// NOTE: We want to use the copy constructor for this class. During
// relaxation, we may try built the segments multiple times. We do
// that by copying the original segment list before lay-out, doing
// a trial lay-out and roll-back to the saved copied if we need to
// to the lay-out again.
class Output_segment
{
public:
// Create an output segment, specifying the type and flags.
Output_segment(elfcpp::Elf_Word, elfcpp::Elf_Word);
// Return the virtual address.
uint64_t
vaddr() const
{ return this->vaddr_; }
// Return the physical address.
uint64_t
paddr() const
{ return this->paddr_; }
// Return the segment type.
elfcpp::Elf_Word
type() const
{ return this->type_; }
// Return the segment flags.
elfcpp::Elf_Word
flags() const
{ return this->flags_; }
// Return the memory size.
uint64_t
memsz() const
{ return this->memsz_; }
// Return the file size.
off_t
filesz() const
{ return this->filesz_; }
// Return the file offset.
off_t
offset() const
{ return this->offset_; }
// Whether this is a segment created to hold large data sections.
bool
is_large_data_segment() const
{ return this->is_large_data_segment_; }
// Record that this is a segment created to hold large data
// sections.
void
set_is_large_data_segment()
{ this->is_large_data_segment_ = true; }
bool
is_unique_segment() const
{ return this->is_unique_segment_; }
// Mark segment as unique, happens when linker plugins request that
// certain input sections be mapped to unique segments.
void
set_is_unique_segment()
{ this->is_unique_segment_ = true; }
// Return the maximum alignment of the Output_data.
uint64_t
maximum_alignment();
// Add the Output_section OS to this PT_LOAD segment. SEG_FLAGS is
// the segment flags to use.
void
add_output_section_to_load(Layout* layout, Output_section* os,
elfcpp::Elf_Word seg_flags);
// Add the Output_section OS to this non-PT_LOAD segment. SEG_FLAGS
// is the segment flags to use.
void
add_output_section_to_nonload(Output_section* os,
elfcpp::Elf_Word seg_flags);
// Remove an Output_section from this segment. It is an error if it
// is not present.
void
remove_output_section(Output_section* os);
// Add an Output_data (which need not be an Output_section) to the
// start of this segment.
void
add_initial_output_data(Output_data*);
// Return true if this segment has any sections which hold actual
// data, rather than being a BSS section.
bool
has_any_data_sections() const;
// Whether this segment has a dynamic relocs.
bool
has_dynamic_reloc() const;
// Return the first section.
Output_section*
first_section() const;
// Return the address of the first section.
uint64_t
first_section_load_address() const
{
const Output_section* os = this->first_section();
return os->has_load_address() ? os->load_address() : os->address();
}
// Return whether the addresses have been set already.
bool
are_addresses_set() const
{ return this->are_addresses_set_; }
// Set the addresses.
void
set_addresses(uint64_t vaddr, uint64_t paddr)
{
this->vaddr_ = vaddr;
this->paddr_ = paddr;
this->are_addresses_set_ = true;
}
// Update the flags for the flags of an output section added to this
// segment.
void
update_flags_for_output_section(elfcpp::Elf_Xword flags)
{
// The ELF ABI specifies that a PT_TLS segment should always have
// PF_R as the flags.
if (this->type() != elfcpp::PT_TLS)
this->flags_ |= flags;
}
// Set the segment flags. This is only used if we have a PHDRS
// clause which explicitly specifies the flags.
void
set_flags(elfcpp::Elf_Word flags)
{ this->flags_ = flags; }
// Set the address of the segment to ADDR and the offset to *POFF
// and set the addresses and offsets of all contained output
// sections accordingly. Set the section indexes of all contained
// output sections starting with *PSHNDX. If RESET is true, first
// reset the addresses of the contained sections. Return the
// address of the immediately following segment. Update *POFF and
// *PSHNDX. This should only be called for a PT_LOAD segment.
uint64_t
set_section_addresses(Layout*, bool reset, uint64_t addr,
unsigned int* increase_relro, bool* has_relro,
off_t* poff, unsigned int* pshndx);
// Set the minimum alignment of this segment. This may be adjusted
// upward based on the section alignments.
void
set_minimum_p_align(uint64_t align)
{
if (align > this->min_p_align_)
this->min_p_align_ = align;
}
// Set the offset of this segment based on the section. This should
// only be called for a non-PT_LOAD segment.
void
set_offset(unsigned int increase);
// Set the TLS offsets of the sections contained in the PT_TLS segment.
void
set_tls_offsets();
// Return the number of output sections.
unsigned int
output_section_count() const;
// Return the section attached to the list segment with the lowest
// load address. This is used when handling a PHDRS clause in a
// linker script.
Output_section*
section_with_lowest_load_address() const;
// Write the segment header into *OPHDR.
template<int size, bool big_endian>
void
write_header(elfcpp::Phdr_write<size, big_endian>*);
// Write the section headers of associated sections into V.
template<int size, bool big_endian>
unsigned char*
write_section_headers(const Layout*, const Stringpool*, unsigned char* v,
unsigned int* pshndx) const;
// Print the output sections in the map file.
void
print_sections_to_mapfile(Mapfile*) const;
private:
typedef std::vector<Output_data*> Output_data_list;
// Find the maximum alignment in an Output_data_list.
static uint64_t
maximum_alignment_list(const Output_data_list*);
// Return whether the first data section is a relro section.
bool
is_first_section_relro() const;
// Set the section addresses in an Output_data_list.
uint64_t
set_section_list_addresses(Layout*, bool reset, Output_data_list*,
uint64_t addr, off_t* poff, unsigned int* pshndx,
bool* in_tls);
// Return the number of Output_sections in an Output_data_list.
unsigned int
output_section_count_list(const Output_data_list*) const;
// Return whether an Output_data_list has a dynamic reloc.
bool
has_dynamic_reloc_list(const Output_data_list*) const;
// Find the section with the lowest load address in an
// Output_data_list.
void
lowest_load_address_in_list(const Output_data_list* pdl,
Output_section** found,
uint64_t* found_lma) const;
// Find the first and last entries by address.
void
find_first_and_last_list(const Output_data_list* pdl,
const Output_data** pfirst,
const Output_data** plast) const;
// Write the section headers in the list into V.
template<int size, bool big_endian>
unsigned char*
write_section_headers_list(const Layout*, const Stringpool*,
const Output_data_list*, unsigned char* v,
unsigned int* pshdx) const;
// Print a section list to the mapfile.
void
print_section_list_to_mapfile(Mapfile*, const Output_data_list*) const;
// NOTE: We want to use the copy constructor. Currently, shallow copy
// works for us so we do not need to write our own copy constructor.
// The list of output data attached to this segment.
Output_data_list output_lists_[ORDER_MAX];
// The segment virtual address.
uint64_t vaddr_;
// The segment physical address.
uint64_t paddr_;
// The size of the segment in memory.
uint64_t memsz_;
// The maximum section alignment. The is_max_align_known_ field
// indicates whether this has been finalized.
uint64_t max_align_;
// The required minimum value for the p_align field. This is used
// for PT_LOAD segments. Note that this does not mean that
// addresses should be aligned to this value; it means the p_paddr
// and p_vaddr fields must be congruent modulo this value. For
// non-PT_LOAD segments, the dynamic linker works more efficiently
// if the p_align field has the more conventional value, although it
// can align as needed.
uint64_t min_p_align_;
// The offset of the segment data within the file.
off_t offset_;
// The size of the segment data in the file.
off_t filesz_;
// The segment type;
elfcpp::Elf_Word type_;
// The segment flags.
elfcpp::Elf_Word flags_;
// Whether we have finalized max_align_.
bool is_max_align_known_ : 1;
// Whether vaddr and paddr were set by a linker script.
bool are_addresses_set_ : 1;
// Whether this segment holds large data sections.
bool is_large_data_segment_ : 1;
// Whether this was marked as a unique segment via a linker plugin.
bool is_unique_segment_ : 1;
};
// This class represents the output file.
class Output_file
{
public:
Output_file(const char* name);
// Indicate that this is a temporary file which should not be
// output.
void
set_is_temporary()
{ this->is_temporary_ = true; }
// Try to open an existing file. Returns false if the file doesn't
// exist, has a size of 0 or can't be mmaped. This method is
// thread-unsafe. If BASE_NAME is not NULL, use the contents of
// that file as the base for incremental linking.
bool
open_base_file(const char* base_name, bool writable);
// Open the output file. FILE_SIZE is the final size of the file.
// If the file already exists, it is deleted/truncated. This method
// is thread-unsafe.
void
open(off_t file_size);
// Resize the output file. This method is thread-unsafe.
void
resize(off_t file_size);
// Close the output file (flushing all buffered data) and make sure
// there are no errors. This method is thread-unsafe.
void
close();
// Return the size of this file.
off_t
filesize()
{ return this->file_size_; }
// Return the name of this file.
const char*
filename()
{ return this->name_; }
// We currently always use mmap which makes the view handling quite
// simple. In the future we may support other approaches.
// Write data to the output file.
void
write(off_t offset, const void* data, size_t len)
{ memcpy(this->base_ + offset, data, len); }
// Get a buffer to use to write to the file, given the offset into
// the file and the size.
unsigned char*
get_output_view(off_t start, size_t size)
{
gold_assert(start >= 0
&& start + static_cast<off_t>(size) <= this->file_size_);
return this->base_ + start;
}
// VIEW must have been returned by get_output_view. Write the
// buffer to the file, passing in the offset and the size.
void
write_output_view(off_t, size_t, unsigned char*)
{ }
// Get a read/write buffer. This is used when we want to write part
// of the file, read it in, and write it again.
unsigned char*
get_input_output_view(off_t start, size_t size)
{ return this->get_output_view(start, size); }
// Write a read/write buffer back to the file.
void
write_input_output_view(off_t, size_t, unsigned char*)
{ }
// Get a read buffer. This is used when we just want to read part
// of the file back it in.
const unsigned char*
get_input_view(off_t start, size_t size)
{ return this->get_output_view(start, size); }
// Release a read bfufer.
void
free_input_view(off_t, size_t, const unsigned char*)
{ }
private:
// Map the file into memory or, if that fails, allocate anonymous
// memory.
void
map();
// Allocate anonymous memory for the file.
bool
map_anonymous();
// Map the file into memory.
bool
map_no_anonymous(bool);
// Unmap the file from memory (and flush to disk buffers).
void
unmap();
// File name.
const char* name_;
// File descriptor.
int o_;
// File size.
off_t file_size_;
// Base of file mapped into memory.
unsigned char* base_;
// True iff base_ points to a memory buffer rather than an output file.
bool map_is_anonymous_;
// True if base_ was allocated using new rather than mmap.
bool map_is_allocated_;
// True if this is a temporary file which should not be output.
bool is_temporary_;
};
} // End namespace gold.
#endif // !defined(GOLD_OUTPUT_H)
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