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548061812a
binutils-gdb/gold/output.h
Ian Lance Taylor 0496d5e5b4 Force PT_LOAD segments to be aligned to the page size.
2007-08-21 21:03:50 +00:00

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// output.h -- manage the output file for gold -*- C++ -*-
#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(off_t data_size = 0)
: address_(0), data_size_(data_size), offset_(-1)
{ }
virtual
~Output_data();
// Return the address. This is only valid after Layout::finalize is
// finished.
uint64_t
address() const
{ return this->address_; }
// Return the size of the data. This must be valid after
// Layout::finalize calls set_address, but need not be valid before
// then.
off_t
data_size() const
{ return this->data_size_; }
// Return the file offset. This is only valid after
// Layout::finalize is finished.
off_t
offset() const
{ 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. This is called
// during Layout::finalize.
void
set_address(uint64_t addr, off_t off);
// 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 all sizes must
// now be fixed.
static void
layout_complete()
{ Output_data::sizes_are_fixed = true; }
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(); }
// Set the address and file offset of the data. This only needs to
// be implemented if the child needs to know. The child class can
// set its size in this call.
virtual void
do_set_address(uint64_t, off_t)
{ }
// Functions that child classes may call.
// Set the size of the data.
void
set_data_size(off_t data_size)
{
gold_assert(!Output_data::sizes_are_fixed);
this->data_size_ = data_size;
}
// Return default alignment for a size--32 or 64.
static uint64_t
default_alignment(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 after we set the section addresses.
static bool sizes_are_fixed;
// Memory address in file (not always meaningful).
uint64_t address_;
// Size of data in file.
off_t data_size_;
// Offset within file.
off_t offset_;
};
// Output the section headers.
class Output_section_headers : public Output_data
{
public:
Output_section_headers(int size,
bool big_endian,
const Layout*,
const Layout::Segment_list*,
const Layout::Section_list*,
const Stringpool*);
// 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(this->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*);
int size_;
bool big_endian_;
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(int size, bool big_endian,
const Layout::Segment_list& segment_list);
// 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(this->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*);
int size_;
bool big_endian_;
const Layout::Segment_list& segment_list_;
};
// Output the ELF file header.
class Output_file_header : public Output_data
{
public:
Output_file_header(int size,
bool big_endian,
const General_options&,
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);
// 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(this->size_); }
// Set the address and offset--we only implement this for error
// checking.
void
do_set_address(uint64_t, off_t off) const
{ gold_assert(off == 0); }
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*);
int size_;
bool big_endian_;
const General_options& options_;
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)
: Output_data(data_size), output_section_(NULL), addralign_(addralign)
{ }
Output_section_data(uint64_t addralign)
: Output_data(0), 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 output address is known.
// OUTPUT_SECTION_ADDRESS is the address of the output section which
// this is a part of. If this function returns true, it sets
// *POUTPUT to the output address.
virtual bool
output_address(const Relobj* object, unsigned int shndx, off_t offset,
uint64_t output_section_address, uint64_t *poutput) const
{
return this->do_output_address(object, shndx, offset,
output_section_address, poutput);
}
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_address.
virtual bool
do_output_address(const Relobj*, unsigned int, off_t, uint64_t,
uint64_t*) const
{ return false; }
// 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_;
};
// 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)
{ }
// Add more data.
void
add_data(const std::string& add)
{
this->data_.append(add);
this->set_data_size(this->data_.size());
}
// Write the data to the output file.
void
do_write(Output_file*);
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)
{ }
// Write the data the output file.
void
do_write(Output_file*);
private:
const unsigned char* p_;
};
// A place holder for data written out via some other mechanism.
class Output_data_space : public Output_section_data
{
public:
Output_data_space(off_t data_size, uint64_t addralign)
: Output_section_data(data_size, addralign)
{ }
explicit Output_data_space(uint64_t addralign)
: Output_section_data(addralign)
{ }
// Set the size.
void
set_space_size(off_t space_size)
{ this->set_data_size(space_size); }
// Set the alignment.
void
set_space_alignment(uint64_t align)
{ this->set_addralign(align); }
// Write out the data--this must be handled 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)
{ }
// This is called to set the address and file offset. Here we make
// sure that the Stringpool is finalized.
void
do_set_address(uint64_t, off_t);
// Write out the data.
void
do_write(Output_file*);
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)
: address_(address), local_sym_index_(GSYM_CODE), type_(type),
shndx_(INVALID_CODE)
{
this->u1_.gsym = gsym;
this->u2_.od = od;
}
Output_reloc(Symbol* gsym, unsigned int type, Relobj* relobj,
unsigned int shndx, Address address)
: address_(address), local_sym_index_(GSYM_CODE), type_(type),
shndx_(shndx)
{
gold_assert(shndx != INVALID_CODE);
this->u1_.gsym = gsym;
this->u2_.relobj = relobj;
}
// 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)
: address_(address), local_sym_index_(local_sym_index), type_(type),
shndx_(INVALID_CODE)
{
gold_assert(local_sym_index != GSYM_CODE
&& local_sym_index != INVALID_CODE);
this->u1_.relobj = relobj;
this->u2_.od = od;
}
Output_reloc(Sized_relobj<size, big_endian>* relobj,
unsigned int local_sym_index,
unsigned int type,
unsigned int shndx,
Address address)
: address_(address), local_sym_index_(local_sym_index), type_(type),
shndx_(shndx)
{
gold_assert(local_sym_index != GSYM_CODE
&& local_sym_index != INVALID_CODE);
gold_assert(shndx != INVALID_CODE);
this->u1_.relobj = relobj;
this->u2_.relobj = relobj;
}
// A reloc against the STT_SECTION symbol of an output section.
Output_reloc(Output_section* os, unsigned int type, Output_data* od,
Address address)
: address_(address), local_sym_index_(SECTION_CODE), type_(type),
shndx_(INVALID_CODE)
{
this->u1_.os = os;
this->u2_.od = od;
}
Output_reloc(Output_section* os, unsigned int type, Relobj* relobj,
unsigned int shndx, Address address)
: address_(address), local_sym_index_(SECTION_CODE), type_(type),
shndx_(shndx)
{
gold_assert(shndx != INVALID_CODE);
this->u1_.os = os;
this->u2_.relobj = 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;
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_;
// 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)
: rel_(gsym, type, od, address), addend_(addend)
{ }
Output_reloc(Symbol* gsym, unsigned int type, Relobj* relobj,
unsigned int shndx, Address address, Addend addend)
: rel_(gsym, type, relobj, shndx, address), 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)
: rel_(relobj, local_sym_index, type, od, address), 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)
: rel_(relobj, local_sym_index, type, shndx, address),
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
{
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(Output_data::default_alignment(size))
{ }
// Write out the data.
void
do_write(Output_file*);
protected:
// Set the entry size and the link.
void
do_adjust_output_section(Output_section *os);
// Add a relocation entry.
void
add(const Output_reloc_type& reloc)
{
this->relocs_.push_back(reloc);
this->set_data_size(this->relocs_.size() * reloc_size);
}
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(Output_reloc_type(gsym, type, od, address)); }
void
add_global(Symbol* gsym, unsigned int type, Relobj* relobj,
unsigned int shndx, Address address)
{ this->add(Output_reloc_type(gsym, type, relobj, shndx, address)); }
// 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(Output_reloc_type(relobj, local_sym_index, type, od, address)); }
void
add_local(Sized_relobj<size, big_endian>* relobj,
unsigned int local_sym_index, unsigned int type,
unsigned int shndx, Address address)
{ this->add(Output_reloc_type(relobj, local_sym_index, type, shndx,
address)); }
// 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)
{ this->add(Output_reloc_type(os, type, od, address)); }
void
add_output_section(Output_section* os, unsigned int type,
Relobj* relobj, unsigned int shndx, Address address)
{ this->add(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(Output_reloc_type(gsym, type, od, address, addend)); }
void
add_global(Symbol* gsym, unsigned int type, Relobj* relobj,
unsigned int shndx, Address address, Addend addend)
{ this->add(Output_reloc_type(gsym, type, relobj, shndx, address, addend)); }
// 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(Output_reloc_type(relobj, local_sym_index, type, od, address,
addend));
}
void
add_local(Sized_relobj<size, big_endian>* relobj,
unsigned int local_sym_index, unsigned int type,
unsigned int shndx, Address address, Addend addend)
{
this->add(Output_reloc_type(relobj, local_sym_index, type, shndx, address,
addend));
}
// 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(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(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
{
public:
typedef typename elfcpp::Elf_types<size>::Elf_Addr Valtype;
Output_data_got(const General_options* options)
: Output_section_data(Output_data::default_alignment(size)),
options_(options), 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 local symbol to the GOT. This returns the
// offset of the new entry from the start of the GOT.
unsigned int
add_local(Object* object, unsigned int sym_index)
{
this->entries_.push_back(Got_entry(object, sym_index));
this->set_got_size();
return this->last_got_offset();
}
// 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();
}
// 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(Object* 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(const General_options*, unsigned char* pov) const;
private:
enum
{
GSYM_CODE = -1U,
CONSTANT_CODE = -2U
};
union
{
// For a local symbol, the object.
Object* 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_data_size(this->got_offset(this->entries_.size())); }
// Options.
const General_options* options_;
// 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(const Target* target, Stringpool* pool)
: Output_section_data(Output_data::default_alignment(target->get_size())),
target_(target), 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, NULL))); }
void
add_string(elfcpp::DT tag, const std::string& str)
{ this->add_string(tag, str.c_str()); }
// Set the final data size.
void
do_set_address(uint64_t, off_t);
// Write out the dynamic entries.
void
do_write(Output_file*);
protected:
// Adjust the output section to set the entry size.
void
do_adjust_output_section(Output_section*);
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 target.
const Target* target_;
// 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. Return the offset within the output section.
template<int size, bool big_endian>
off_t
add_input_section(Relobj* object, unsigned int shndx, const char *name,
const elfcpp::Shdr<size, big_endian>& shdr);
// 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 section index in the output file.
unsigned int
do_out_shndx() const
{ return this->out_shndx_; }
// Set the output section index.
void
do_set_out_shndx(unsigned int shndx)
{ this->out_shndx_ = shndx; }
// 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 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;
// Set the address 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 the final addresses
// here.
void
do_set_address(uint64_t, off_t);
// 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.
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; }
// 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;
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) const
{
return (this->shndx_ == (is_string
? MERGE_STRING_SECTION_CODE
: MERGE_DATA_SECTION_CODE)
&& this->u1_.entsize == entsize);
}
// 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. SECOFF is the file offset of the enclosing
// section.
void
set_address(uint64_t addr, off_t off, off_t secoff);
// 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 address is known.
// OUTPUT_SECTION_ADDRESS is the address of the output section
// which this is a part of. If this function returns true, it
// sets *POUTPUT to the output address.
bool
output_address(const Relobj* object, unsigned int shndx, off_t offset,
uint64_t output_section_address, uint64_t *poutput) const;
// Write out the data. This does nothing for an input section.
void
write(Output_file*);
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;
// 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.
elfcpp::Elf_Word type_;
// The section flags.
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_;
// 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;
};
// 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*);
// 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();
// 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;
// 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 General_options& options);
// Open the output file. FILE_SIZE is the final size of the file.
void
open(off_t file_size);
// Close the output file and make sure there are no error.
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, off_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, off_t size)
{
gold_assert(start >= 0 && size >= 0 && start + 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, off_t, unsigned char*)
{ }
private:
// General options.
const General_options& options_;
// File name.
const char* name_;
// File descriptor.
int o_;
// File size.
off_t file_size_;
// Base of file mapped into memory.
unsigned char* base_;
};
} // End namespace gold.
#endif // !defined(GOLD_OUTPUT_H)
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