binutils-gdb/gold/output.h

2385 lines
70 KiB
C++

// output.h -- manage the output file for gold -*- C++ -*-
// Copyright 2006, 2007 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 "layout.h"
#include "reloc-types.h"
namespace gold
{
class General_options;
class Object;
class Symbol;
class Output_file;
class Output_section;
class Target;
template<int size, bool big_endian>
class Sized_target;
template<int size, bool big_endian>
class Sized_relobj;
// 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),
dynamic_reloc_count_(0)
{ }
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_;
}
// 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_;
}
// Return the required alignment.
uint64_t
addralign() const
{ return this->do_addralign(); }
// 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 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;
}
// 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; }
// Count the number of dynamic relocations applied to this section.
void
add_dynamic_reloc()
{ ++this->dynamic_reloc_count_; }
// Return the number of dynamic relocations applied to this section.
unsigned int
dynamic_reloc_count() const
{ return this->dynamic_reloc_count_; }
// 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_; }
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 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 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 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(); }
// 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(); }
// Functions that child classes may call.
// Set the size of the data.
void
set_data_size(off_t data_size)
{
gold_assert(!this->is_data_size_valid_);
this->data_size_ = data_size;
this->is_data_size_valid_ = 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_;
// Whether data_size_ is valid.
bool is_data_size_valid_;
// Whether offset_ is valid.
bool is_offset_valid_;
// Count of dynamic relocations applied to this section.
unsigned int dynamic_reloc_count_;
};
// 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 Stringpool*);
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(); }
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*);
const Layout* layout_;
const Layout::Segment_list* segment_list_;
const Layout::Section_list* unattached_section_list_;
const Stringpool* secnamepool_;
};
// 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(); }
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*);
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*,
const char* entry);
// 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(); }
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();
const Target* target_;
const Symbol_table* symtab_;
const Output_segment_headers* segment_header_;
const Output_section_headers* section_header_;
const Output_section* shstrtab_;
const char* entry_;
};
// 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)
: Output_data(), output_section_(NULL), addralign_(addralign)
{ this->set_data_size(data_size); }
Output_section_data(uint64_t addralign)
: Output_data(), output_section_(NULL), addralign_(addralign)
{ }
// Return the 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 section index of the output section.
unsigned int
do_out_shndx() const;
// Set the alignment.
void
set_addralign(uint64_t addralign)
{ this->addralign_ = addralign; }
private:
// The output section for this section.
const 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)
{ }
// Get the current data size.
off_t
current_data_size() const
{ return this->current_data_size_for_child(); }
// 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), data_(data)
{ }
Output_data_const(const char* p, off_t len, uint64_t addralign)
: Output_section_data(len, addralign), data_(p, len)
{ }
Output_data_const(const unsigned char* p, off_t len, uint64_t addralign)
: Output_section_data(len, addralign),
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()); }
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)
: Output_section_data(len, addralign), p_(p)
{ }
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()); }
private:
const unsigned char* p_;
};
// 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)
: Output_section_data(data_size, addralign)
{ }
protected:
// Write out the data--the actual data must be written out
// elsewhere.
void
do_write(Output_file*)
{ }
};
// 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)
: Output_section_data_build(addralign)
{ }
// 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*)
{ }
};
// 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 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()); }
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, 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;
// 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)
{ }
// A reloc against a global symbol.
Output_reloc(Symbol* gsym, unsigned int type, Output_data* od,
Address address, bool is_relative);
Output_reloc(Symbol* gsym, unsigned int type, Relobj* relobj,
unsigned int shndx, Address address, bool is_relative);
// 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, bool is_relative);
Output_reloc(Sized_relobj<size, big_endian>* relobj,
unsigned int local_sym_index, unsigned int type,
unsigned int shndx, Address address, bool is_relative);
// A reloc against the STT_SECTION symbol of an output section.
Output_reloc(Output_section* os, unsigned int type, Output_data* od,
Address address);
Output_reloc(Output_section* os, unsigned int type, Relobj* relobj,
unsigned int shndx, Address address);
// Return TRUE if this is a RELATIVE relocation.
bool
is_relative() const
{ return this->is_relative_; }
// Get the value of the symbol referred to by a Rel relocation.
Address
symbol_value() const;
// 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;
private:
// Return the symbol index. We can't do a double template
// specialization, so we do a secondary template here.
unsigned int
get_symbol_index() const;
// Codes for local_sym_index_.
enum
{
// Global symbol.
GSYM_CODE = -1U,
// Output section.
SECTION_CODE = -2U,
// Invalid uninitialized entry.
INVALID_CODE = -3U
};
union
{
// For a local symbol, 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, the symbol. If this is NULL, it indicates
// a relocation against the undefined 0 symbol.
Symbol* gsym;
// For a relocation against an output section, the output section.
Output_section* os;
} u1_;
union
{
// If shndx_ is not INVALID CODE, the object which holds the input
// section being used to specify the reloc address.
Relobj* relobj;
// If 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_;
// For a local symbol, the local symbol index. This is GSYM_CODE
// for a global symbol, or INVALID_CODE for an uninitialized value.
unsigned int local_sym_index_;
// The reloc type--a processor specific code.
unsigned int type_ : 31;
// True if the relocation is a RELATIVE relocation.
bool is_relative_ : 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)
: rel_(gsym, type, od, address, is_relative), addend_(addend)
{ }
Output_reloc(Symbol* gsym, unsigned int type, Relobj* relobj,
unsigned int shndx, Address address, Addend addend,
bool is_relative)
: rel_(gsym, type, relobj, shndx, address, is_relative), 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)
: rel_(relobj, local_sym_index, type, od, address, is_relative),
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)
: rel_(relobj, local_sym_index, type, shndx, address, is_relative),
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)
: rel_(os, type, od, address), addend_(addend)
{ }
Output_reloc(Output_section* os, unsigned int type, Relobj* relobj,
unsigned int shndx, Address address, Addend addend)
: rel_(os, type, relobj, shndx, address), addend_(addend)
{ }
// Write the reloc entry to an output view.
void
write(unsigned char* pov) const;
private:
// The basic reloc.
Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian> rel_;
// The addend.
Addend addend_;
};
// 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_section_data_build
{
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()
: Output_section_data_build(Output_data::default_alignment_for_size(size))
{ }
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);
// 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);
od->add_dynamic_reloc();
}
private:
typedef std::vector<Output_reloc_type> Relocs;
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()
: Output_data_reloc_base<elfcpp::SHT_REL, dynamic, size, big_endian>()
{ }
// 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)); }
void
add_global(Symbol* gsym, unsigned int type, Output_data* od, Relobj* relobj,
unsigned int shndx, Address address)
{ this->add(od, Output_reloc_type(gsym, type, relobj, shndx, address,
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)); }
void
add_global_relative(Symbol* gsym, unsigned int type, Output_data* od,
Relobj* relobj, unsigned int shndx, Address address)
{ this->add(od, Output_reloc_type(gsym, type, relobj, shndx, address,
true)); }
// 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)); }
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)); }
// 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)); }
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)); }
// 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)); }
void
add_output_section(Output_section* os, unsigned int type, Output_data* od,
Relobj* relobj, unsigned int shndx, Address address)
{ this->add(od, Output_reloc_type(os, type, 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()
: Output_data_reloc_base<elfcpp::SHT_RELA, dynamic, size, big_endian>()
{ }
// 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)); }
void
add_global(Symbol* gsym, unsigned int type, Output_data* od, Relobj* relobj,
unsigned int shndx, Address address,
Addend addend)
{ this->add(od, Output_reloc_type(gsym, type, relobj, shndx, address,
addend, 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)
{ this->add(od, Output_reloc_type(gsym, type, od, address, addend, true)); }
void
add_global_relative(Symbol* gsym, unsigned int type, Output_data* od,
Relobj* relobj, unsigned int shndx, Address address,
Addend addend)
{ this->add(od, Output_reloc_type(gsym, type, relobj, shndx, address,
addend, true)); }
// 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));
}
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));
}
// 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)
{
this->add(od, Output_reloc_type(relobj, local_sym_index, type, od, address,
addend, true));
}
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)
{
this->add(od, Output_reloc_type(relobj, local_sym_index, type, shndx,
address, addend, true));
}
// 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(os, Output_reloc_type(os, type, od, address, addend)); }
void
add_output_section(Output_section* os, unsigned int type, Relobj* relobj,
unsigned int shndx, Address address, Addend addend)
{ this->add(os, Output_reloc_type(os, type, relobj, shndx, address,
addend)); }
};
// 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.
template<int size, bool big_endian>
class Output_data_got : public Output_section_data_build
{
public:
typedef typename elfcpp::Elf_types<size>::Elf_Addr Valtype;
typedef Output_data_reloc<elfcpp::SHT_REL, true, size, big_endian> Rel_dyn;
typedef Output_data_reloc<elfcpp::SHT_RELA, true, size, big_endian> Rela_dyn;
Output_data_got()
: Output_section_data_build(Output_data::default_alignment_for_size(size)),
entries_()
{ }
// 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);
// 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, Rel_dyn* rel_dyn, unsigned int r_type);
void
add_global_with_rela(Symbol* gsym, Rela_dyn* rela_dyn, unsigned int r_type);
// 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(Sized_relobj<size, big_endian>* object, unsigned int sym_index);
// 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_local_with_rel(Sized_relobj<size, big_endian>* object,
unsigned int sym_index, Rel_dyn* rel_dyn,
unsigned int r_type);
void
add_local_with_rela(Sized_relobj<size, big_endian>* object,
unsigned int sym_index, Rela_dyn* rela_dyn,
unsigned int r_type);
// Add an entry (or pair of entries) for a global TLS 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_tls(Symbol* gsym, bool need_pair);
// Add an entry for a global TLS symbol to the GOT, and add a dynamic
// relocation of type R_TYPE.
void
add_global_tls_with_rel(Symbol* gsym, Rel_dyn* rel_dyn,
unsigned int r_type);
void
add_global_tls_with_rela(Symbol* gsym, Rela_dyn* rela_dyn,
unsigned int r_type);
// Add a pair of entries for a global TLS symbol to the GOT, and add
// dynamic relocations of type MOD_R_TYPE and DTV_R_TYPE, respectively.
void
add_global_tls_with_rel(Symbol* gsym, Rel_dyn* rel_dyn,
unsigned int mod_r_type,
unsigned int dtv_r_type);
void
add_global_tls_with_rela(Symbol* gsym, Rela_dyn* rela_dyn,
unsigned int mod_r_type,
unsigned int dtv_r_type);
// Add an entry (or pair of entries) for a local TLS 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_tls(Sized_relobj<size, big_endian>* object,
unsigned int sym_index, bool need_pair);
// Add an entry (or pair of entries) for a local TLS symbol to the GOT,
// and add a dynamic relocation of type R_TYPE for the first GOT entry.
// Because this is a local symbol, the first GOT entry can be relocated
// relative to a section symbol, and the second GOT entry will have an
// dtv-relative value that can be computed at link time.
void
add_local_tls_with_rel(Sized_relobj<size, big_endian>* object,
unsigned int sym_index, unsigned int shndx,
bool need_pair, Rel_dyn* rel_dyn,
unsigned int r_type);
void
add_local_tls_with_rela(Sized_relobj<size, big_endian>* object,
unsigned int sym_index, unsigned int shndx,
bool need_pair, Rela_dyn* rela_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)
{
this->entries_.push_back(Got_entry(constant));
this->set_got_size();
return this->last_got_offset();
}
protected:
// Write out the GOT table.
void
do_write(Output_file*);
private:
// This POD class holds a single GOT entry.
class Got_entry
{
public:
// Create a zero entry.
Got_entry()
: local_sym_index_(CONSTANT_CODE)
{ this->u_.constant = 0; }
// Create a global symbol entry.
explicit Got_entry(Symbol* gsym)
: local_sym_index_(GSYM_CODE)
{ this->u_.gsym = gsym; }
// Create a local symbol entry.
Got_entry(Sized_relobj<size, big_endian>* object,
unsigned int local_sym_index)
: local_sym_index_(local_sym_index)
{
gold_assert(local_sym_index != GSYM_CODE
&& local_sym_index != CONSTANT_CODE);
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)
{ this->u_.constant = constant; }
// Write the GOT entry to an output view.
void
write(unsigned char* pov) const;
private:
enum
{
GSYM_CODE = -1U,
CONSTANT_CODE = -2U
};
union
{
// For a local symbol, the object.
Sized_relobj<size, big_endian>* 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_;
};
typedef std::vector<Got_entry> Got_entries;
// Return the offset into the GOT of GOT entry I.
unsigned int
got_offset(unsigned int i) const
{ return i * (size / 8); }
// Return the offset into the GOT of the last entry added.
unsigned int
last_got_offset() const
{ return this->got_offset(this->entries_.size() - 1); }
// Set the size of the section.
void
set_got_size()
{ this->set_current_data_size(this->got_offset(this->entries_.size())); }
// The list of GOT entries.
Got_entries entries_;
};
// 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 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 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*);
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), classification_(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),
classification_(section_size
? DYNAMIC_SECTION_SIZE
: DYNAMIC_SECTION_ADDRESS)
{ this->u_.od = od; }
// Create an entry with the address of a symbol.
Dynamic_entry(elfcpp::DT tag, const Symbol* sym)
: tag_(tag), classification_(DYNAMIC_SYMBOL)
{ this->u_.sym = sym; }
// Create an entry with a string.
Dynamic_entry(elfcpp::DT tag, const char* str)
: tag_(tag), classification_(DYNAMIC_STRING)
{ this->u_.str = str; }
// Write the dynamic entry to an output view.
template<int size, bool big_endian>
void
write(unsigned char* pov, const Stringpool* ACCEPT_SIZE_ENDIAN) const;
private:
enum Classification
{
// Number.
DYNAMIC_NUMBER,
// Section address.
DYNAMIC_SECTION_ADDRESS,
// Section size.
DYNAMIC_SECTION_SIZE,
// Symbol adress.
DYNAMIC_SYMBOL,
// String.
DYNAMIC_STRING
};
union
{
// For DYNAMIC_NUMBER.
unsigned int val;
// For DYNAMIC_SECTION_ADDRESS and DYNAMIC_SECTION_SIZE.
const Output_data* od;
// For DYNAMIC_SYMBOL.
const Symbol* sym;
// For DYNAMIC_STRING.
const char* str;
} u_;
// The dynamic tag.
elfcpp::DT tag_;
// The type of entry.
Classification classification_;
};
// 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_;
};
// 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 -1U if more than
// one. Return the offset within the output section.
template<int size, bool big_endian>
off_t
add_input_section(Sized_relobj<size, big_endian>* object, unsigned int shndx,
const char *name,
const elfcpp::Shdr<size, big_endian>& shdr,
unsigned int reloc_shndx);
// Add generated data POSD to this output section.
void
add_output_section_data(Output_section_data* posd);
// 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_; }
// Return the entsize field.
uint64_t
entsize() const
{ return this->entsize_; }
// Set the entsize field.
void
set_entsize(uint64_t v);
// 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);
return this->info_;
}
// Set the info field to the output section index of a section.
void
set_info_section(const Output_data* od)
{
gold_assert(this->info_ == 0);
this->info_section_ = od;
}
// Set the info field to a constant.
void
set_info(unsigned int v)
{
gold_assert(this->info_section_ == NULL);
this->info_ = v;
}
// Set the addralign field.
void
set_addralign(uint64_t v)
{ this->addralign_ = v; }
// 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;
}
// 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_; }
// 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(); }
// 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;
// Return the output address of the start of the merged section for
// input section SHNDX in object OBJECT. This is not necessarily
// the offset corresponding to input offset 0 in the section, since
// the section may be mapped arbitrarily.
uint64_t
starting_output_address(const Relobj* object, unsigned int shndx) const;
// 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;
// Print merge statistics to stderr.
void
print_merge_stats();
protected:
// 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;
}
// 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();
// 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 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_; }
// 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;
}
// This may be implemented by a child class.
virtual void
do_finalize_name(Layout*)
{ }
// 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();
private:
// 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)))
{
gold_assert(shndx != OUTPUT_SECTION_CODE
&& shndx != MERGE_DATA_SECTION_CODE
&& shndx != MERGE_STRING_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_(ffsll(static_cast<long long>(posd->addralign())))
{
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_(ffsll(static_cast<long long>(posd->addralign())))
{
this->u1_.entsize = entsize;
this->u2_.posd = posd;
}
// The required alignment.
uint64_t
addralign() const
{
return (this->p2align_ == 0
? 0
: static_cast<uint64_t>(1) << (this->p2align_ - 1));
}
// Return the required size.
off_t
data_size() const;
// 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);
}
// Set the output section.
void
set_output_section(Output_section* os)
{
gold_assert(!this->is_input_section());
this->u2_.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);
// 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 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
};
// 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);
}
// 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, 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;
} u2_;
};
typedef std::vector<Input_section> Input_section_list;
// Fill data. This is used to fill in data between input sections.
// 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. For a fill we record the
// offset, and the actual data to be written out.
class Fill
{
public:
Fill(off_t section_offset, off_t length)
: section_offset_(section_offset), length_(length)
{ }
// Return section offset.
off_t
section_offset() const
{ return this->section_offset_; }
// Return fill length.
off_t
length() const
{ return this->length_; }
private:
// The offset within the output section.
off_t section_offset_;
// The length of the space to fill.
off_t length_;
};
typedef std::vector<Fill> Fill_list;
// 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.
bool
add_merge_input_section(Relobj* object, unsigned int shndx, uint64_t flags,
uint64_t entsize, uint64_t addralign);
// 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);
// 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 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_data* info_section_;
// If info_section_ is NULL, this is the section info field.
unsigned int info_;
// The section type.
const elfcpp::Elf_Word type_;
// The section flags.
const elfcpp::Elf_Xword flags_;
// 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;
// For SHT_TLS sections, the offset of this section relative to the base
// of the TLS segment.
uint64_t tls_offset_;
};
// 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.
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 maximum alignment of the Output_data.
uint64_t
addralign();
// Add an Output_section to this segment.
void
add_output_section(Output_section* os, elfcpp::Elf_Word seg_flags)
{ this->add_output_section(os, seg_flags, false); }
// Add an Output_section to the start of this segment.
void
add_initial_output_section(Output_section* os, elfcpp::Elf_Word seg_flags)
{ this->add_output_section(os, seg_flags, true); }
// Add an Output_data (which is not an Output_section) to the start
// of this segment.
void
add_initial_output_data(Output_data*);
// Return the number of dynamic relocations applied to this segment.
unsigned int
dynamic_reloc_count() const;
// Set the address of the segment to ADDR and the offset to *POFF
// (aligned if necessary), and set the addresses and offsets of all
// contained output sections accordingly. Set the section indexes
// of all contained output sections starting with *PSHNDX. 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(uint64_t addr, 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_addralign(uint64_t align)
{
gold_assert(!this->is_align_known_);
this->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();
// 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;
// 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 ACCEPT_SIZE_ENDIAN) const;
private:
Output_segment(const Output_segment&);
Output_segment& operator=(const Output_segment&);
typedef std::list<Output_data*> Output_data_list;
// Add an Output_section to this segment, specifying front or back.
void
add_output_section(Output_section*, elfcpp::Elf_Word seg_flags,
bool front);
// Find the maximum alignment in an Output_data_list.
static uint64_t
maximum_alignment(const Output_data_list*);
// Set the section addresses in an Output_data_list.
uint64_t
set_section_list_addresses(Output_data_list*, uint64_t addr, off_t* poff,
unsigned int* pshndx);
// Return the number of Output_sections in an Output_data_list.
unsigned int
output_section_count_list(const Output_data_list*) const;
// Return the number of dynamic relocs in an Output_data_list.
unsigned int
dynamic_reloc_count_list(const Output_data_list*) 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 ACCEPT_SIZE_ENDIAN) const;
// The list of output data with contents attached to this segment.
Output_data_list output_data_;
// The list of output data without contents attached to this segment.
Output_data_list output_bss_;
// 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 segment alignment. The is_align_known_ field indicates
// whether this has been finalized. It can be set to a minimum
// value before it is finalized.
uint64_t 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 align_.
bool is_align_known_;
};
// This class represents the output file.
class Output_file
{
public:
Output_file(const char* name);
// Open the output file. FILE_SIZE is the final size of the file.
void
open(off_t file_size);
// Resize the output file.
void
resize(off_t file_size);
// Close the output file (flushing all buffered data) and make sure
// there are no errors.
void
close();
// 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 and return a pointer to the map.
void
map();
// 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_;
};
} // End namespace gold.
#endif // !defined(GOLD_OUTPUT_H)