// output.h -- manage the output file for gold -*- C++ -*-
-// Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
+// Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
#include <vector>
#include "elfcpp.h"
+#include "mapfile.h"
#include "layout.h"
#include "reloc-types.h"
class Object;
class Symbol;
class Output_file;
+class Output_merge_base;
class Output_section;
class Relocatable_relocs;
class Target;
template<int size, bool big_endian>
class Sized_relobj;
+// This class specifies an input section. It is used as a key type
+// for maps.
+
+class Input_section_specifier
+{
+ public:
+ Input_section_specifier(const Relobj* relobj, unsigned int shndx)
+ : relobj_(relobj), shndx_(shndx)
+ { }
+
+ // Return Relobj of this.
+ const Relobj*
+ relobj() const
+ { return this->relobj_; }
+
+ // Return section index of this.
+ unsigned int
+ shndx() const
+ { return this->shndx_; }
+
+ // Whether this equals to another specifier ISS.
+ bool
+ eq(const Input_section_specifier& iss) const
+ { return this->relobj_ == iss.relobj_ && this->shndx_ == iss.shndx_; }
+
+ // Compute a hash value of this.
+ size_t
+ hash_value() const
+ {
+ return (gold::string_hash<char>(this->relobj_->name().c_str())
+ ^ this->shndx_);
+ }
+
+ // Functors for containers.
+ struct equal_to
+ {
+ bool
+ operator()(const Input_section_specifier& iss1,
+ const Input_section_specifier& iss2) const
+ { return iss1.eq(iss2); }
+ };
+
+ struct hash
+ {
+ size_t
+ operator()(const Input_section_specifier& iss) const
+ { return iss.hash_value(); }
+ };
+
+ private:
+ // An object.
+ const Relobj* relobj_;
+ // A section index.
+ unsigned int shndx_;
+};
+
// An abtract class for data which has to go into the output file.
class Output_data
explicit Output_data()
: address_(0), data_size_(0), offset_(-1),
is_address_valid_(false), is_data_size_valid_(false),
- is_offset_valid_(false),
+ is_offset_valid_(false), is_data_size_fixed_(false),
dynamic_reloc_count_(0)
{ }
return this->data_size_;
}
+ // Return true if data size is fixed.
+ bool
+ is_data_size_fixed() const
+ { return this->is_data_size_fixed_; }
+
// Return the file offset. This is only valid after
// Layout::finalize is finished. For some non-allocated sections,
// it may not be valid until near the end of the link.
{
this->is_address_valid_ = false;
this->is_offset_valid_ = false;
- this->is_data_size_valid_ = false;
+ if (!this->is_data_size_fixed_)
+ this->is_data_size_valid_ = false;
this->do_reset_address_and_file_offset();
}
+ // Return true if address and file offset already have reset values. In
+ // other words, calling reset_address_and_file_offset will not change them.
+ bool
+ address_and_file_offset_have_reset_values() const
+ { return this->do_address_and_file_offset_have_reset_values(); }
+
// Return the required alignment.
uint64_t
addralign() const
is_data_size_valid() const
{ return this->is_data_size_valid_; }
+ // Print information to the map file.
+ void
+ print_to_mapfile(Mapfile* mapfile) const
+ { return this->do_print_to_mapfile(mapfile); }
+
protected:
// Functions that child classes may or in some cases must implement.
do_reset_address_and_file_offset()
{ }
+ // Return true if address and file offset already have reset values. In
+ // other words, calling reset_address_and_file_offset will not change them.
+ // A child class overriding do_reset_address_and_file_offset may need to
+ // also override this.
+ virtual bool
+ do_address_and_file_offset_have_reset_values() const
+ { return !this->is_address_valid_ && !this->is_offset_valid_; }
+
// Set the TLS offset. Called only for SHT_TLS sections.
virtual void
do_set_tls_offset(uint64_t)
do_tls_offset() const
{ gold_unreachable(); }
+ // Print to the map file. This only needs to be implemented by
+ // classes which may appear in a PT_LOAD segment.
+ virtual void
+ do_print_to_mapfile(Mapfile*) const
+ { gold_unreachable(); }
+
// Functions that child classes may call.
+ // Reset the address. The Output_section class needs this when an
+ // SHF_ALLOC input section is added to an output section which was
+ // formerly not SHF_ALLOC.
+ void
+ mark_address_invalid()
+ { this->is_address_valid_ = false; }
+
// Set the size of the data.
void
set_data_size(off_t data_size)
{
- gold_assert(!this->is_data_size_valid_);
+ gold_assert(!this->is_data_size_valid_
+ && !this->is_data_size_fixed_);
this->data_size_ = data_size;
this->is_data_size_valid_ = true;
}
+ // Fix the data size. Once it is fixed, it cannot be changed
+ // and the data size remains always valid.
+ void
+ fix_data_size()
+ {
+ gold_assert(this->is_data_size_valid_);
+ this->is_data_size_fixed_ = true;
+ }
+
// Get the current data size--this is for the convenience of
// sections which build up their size over time.
off_t
bool is_data_size_valid_;
// Whether offset_ is valid.
bool is_offset_valid_;
+ // Whether data size is fixed.
+ bool is_data_size_fixed_;
// Count of dynamic relocations applied to this section.
unsigned int dynamic_reloc_count_;
};
const Layout::Segment_list*,
const Layout::Section_list*,
const Layout::Section_list*,
- const Stringpool*);
+ const Stringpool*,
+ const Output_section*);
protected:
// Write the data to the file.
do_addralign() const
{ return Output_data::default_alignment(); }
+ // Write to a map file.
+ void
+ do_print_to_mapfile(Mapfile* mapfile) const
+ { mapfile->print_output_data(this, _("** section headers")); }
+
+ // Set final data size.
+ void
+ set_final_data_size()
+ { this->set_data_size(this->do_size()); }
+
private:
// Write the data to the file with the right size and endianness.
template<int size, bool big_endian>
void
do_sized_write(Output_file*);
+ // Compute data size.
+ off_t
+ do_size() const;
+
const Layout* layout_;
const Layout::Segment_list* segment_list_;
const Layout::Section_list* section_list_;
const Layout::Section_list* unattached_section_list_;
const Stringpool* secnamepool_;
+ const Output_section* shstrtab_section_;
};
// Output the segment headers.
do_addralign() const
{ return Output_data::default_alignment(); }
+ // Write to a map file.
+ void
+ do_print_to_mapfile(Mapfile* mapfile) const
+ { mapfile->print_output_data(this, _("** segment headers")); }
+
+ // Set final data size.
+ void
+ set_final_data_size()
+ { this->set_data_size(this->do_size()); }
+
private:
// Write the data to the file with the right size and endianness.
template<int size, bool big_endian>
void
do_sized_write(Output_file*);
+ // Compute the current size.
+ off_t
+ do_size() const;
+
const Layout::Segment_list& segment_list_;
};
do_addralign() const
{ return Output_data::default_alignment(); }
+ // Write to a map file.
+ void
+ do_print_to_mapfile(Mapfile* mapfile) const
+ { mapfile->print_output_data(this, _("** file header")); }
+
+ // Set final data size.
+ void
+ set_final_data_size(void)
+ { this->set_data_size(this->do_size()); }
+
private:
// Write the data to the file with the right size and endianness.
template<int size, bool big_endian>
typename elfcpp::Elf_types<size>::Elf_Addr
entry();
+ // Compute the current data size.
+ off_t
+ do_size() const;
+
const Target* target_;
const Symbol_table* symtab_;
const Output_segment_headers* segment_header_;
class Output_section_data : public Output_data
{
public:
- Output_section_data(off_t data_size, uint64_t addralign)
+ Output_section_data(off_t data_size, uint64_t addralign,
+ bool is_data_size_fixed)
: Output_data(), output_section_(NULL), addralign_(addralign)
- { this->set_data_size(data_size); }
+ {
+ this->set_data_size(data_size);
+ if (is_data_size_fixed)
+ this->fix_data_size();
+ }
Output_section_data(uint64_t addralign)
: Output_data(), output_section_(NULL), addralign_(addralign)
{
public:
Output_data_const(const std::string& data, uint64_t addralign)
- : Output_section_data(data.size(), addralign), data_(data)
+ : Output_section_data(data.size(), addralign, true), data_(data)
{ }
Output_data_const(const char* p, off_t len, uint64_t addralign)
- : Output_section_data(len, addralign), data_(p, len)
+ : Output_section_data(len, addralign, true), data_(p, len)
{ }
Output_data_const(const unsigned char* p, off_t len, uint64_t addralign)
- : Output_section_data(len, addralign),
+ : Output_section_data(len, addralign, true),
data_(reinterpret_cast<const char*>(p), len)
{ }
do_write_to_buffer(unsigned char* buffer)
{ memcpy(buffer, this->data_.data(), this->data_.size()); }
+ // Write to a map file.
+ void
+ do_print_to_mapfile(Mapfile* mapfile) const
+ { mapfile->print_output_data(this, _("** fill")); }
+
private:
std::string data_;
};
{
public:
Output_data_const_buffer(const unsigned char* p, off_t len,
- uint64_t addralign)
- : Output_section_data(len, addralign), p_(p)
+ uint64_t addralign, const char* map_name)
+ : Output_section_data(len, addralign, true),
+ p_(p), map_name_(map_name)
{ }
protected:
do_write_to_buffer(unsigned char* buffer)
{ memcpy(buffer, this->p_, this->data_size()); }
+ // Write to a map file.
+ void
+ do_print_to_mapfile(Mapfile* mapfile) const
+ { mapfile->print_output_data(this, _(this->map_name_)); }
+
private:
+ // The data to output.
const unsigned char* p_;
+ // Name to use in a map file. Maps are a rarely used feature, but
+ // the space usage is minor as aren't very many of these objects.
+ const char* map_name_;
};
// A place holder for a fixed amount of data written out via some
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)
+ Output_data_fixed_space(off_t data_size, uint64_t addralign,
+ const char* map_name)
+ : Output_section_data(data_size, addralign, true),
+ map_name_(map_name)
{ }
protected:
void
do_write(Output_file*)
{ }
+
+ // Write to a map file.
+ void
+ do_print_to_mapfile(Mapfile* mapfile) const
+ { mapfile->print_output_data(this, _(this->map_name_)); }
+
+ private:
+ // Name to use in a map file. Maps are a rarely used feature, but
+ // the space usage is minor as aren't very many of these objects.
+ const char* map_name_;
};
// A place holder for variable sized data written out via some other
class Output_data_space : public Output_section_data_build
{
public:
- explicit Output_data_space(uint64_t addralign)
- : Output_section_data_build(addralign)
+ explicit Output_data_space(uint64_t addralign, const char* map_name)
+ : Output_section_data_build(addralign),
+ map_name_(map_name)
{ }
// Set the alignment.
void
do_write(Output_file*)
{ }
+
+ // Write to a map file.
+ void
+ do_print_to_mapfile(Mapfile* mapfile) const
+ { mapfile->print_output_data(this, _(this->map_name_)); }
+
+ private:
+ // Name to use in a map file. Maps are a rarely used feature, but
+ // the space usage is minor as aren't very many of these objects.
+ const char* map_name_;
+};
+
+// Fill fixed space with zeroes. This is just like
+// Output_data_fixed_space, except that the map name is known.
+
+class Output_data_zero_fill : public Output_section_data
+{
+ public:
+ Output_data_zero_fill(off_t data_size, uint64_t addralign)
+ : Output_section_data(data_size, addralign, true)
+ { }
+
+ protected:
+ // There is no data to write out.
+ void
+ do_write(Output_file*)
+ { }
+
+ // Write to a map file.
+ void
+ do_print_to_mapfile(Mapfile* mapfile) const
+ { mapfile->print_output_data(this, "** zero fill"); }
};
// A string table which goes into an output section.
do_write_to_buffer(unsigned char* buffer)
{ this->strtab_->write_to_buffer(buffer, this->data_size()); }
+ // Write to a map file.
+ void
+ do_print_to_mapfile(Mapfile* mapfile) const
+ { mapfile->print_output_data(this, _("** string table")); }
+
private:
Stringpool* strtab_;
};
typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
typedef typename elfcpp::Elf_types<size>::Elf_Addr Addend;
+ static const Address invalid_address = static_cast<Address>(0) - 1;
+
// An uninitialized entry. We need this because we want to put
// instances of this class into an STL container.
Output_reloc()
Output_reloc(Symbol* gsym, unsigned int type, Output_data* od,
Address address, bool is_relative);
- Output_reloc(Symbol* gsym, unsigned int type, Relobj* relobj,
+ Output_reloc(Symbol* gsym, unsigned int type,
+ Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address, bool is_relative);
// A reloc against a local symbol or local section symbol.
Output_reloc(Output_section* os, unsigned int type, Output_data* od,
Address address);
- Output_reloc(Output_section* os, unsigned int type, Relobj* relobj,
+ Output_reloc(Output_section* os, unsigned int type,
+ Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address);
// Return TRUE if this is a RELATIVE relocation.
// For a local section symbol, return the offset of the input
// section within the output section. ADDEND is the addend being
// applied to the input section.
- section_offset_type
+ Address
local_section_offset(Addend addend) const;
// Get the value of the symbol referred to by a Rel relocation when
template<typename Write_rel>
void write_rel(Write_rel*) const;
+ // This is used when sorting dynamic relocs. Return -1 to sort this
+ // reloc before R2, 0 to sort the same as R2, 1 to sort after R2.
+ int
+ compare(const Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>& r2)
+ const;
+
+ // Return whether this reloc should be sorted before the argument
+ // when sorting dynamic relocs.
+ bool
+ sort_before(const Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>&
+ r2) const
+ { return this->compare(r2) < 0; }
+
private:
// Record that we need a dynamic symbol index.
void
unsigned int
get_symbol_index() const;
+ // Return the output address.
+ Address
+ get_address() const;
+
// Codes for local_sym_index_.
enum
{
{
// If this->shndx_ is not INVALID CODE, the object which holds the
// input section being used to specify the reloc address.
- Relobj* relobj;
+ Sized_relobj<size, big_endian>* relobj;
// If this->shndx_ is INVALID_CODE, the output data being used to
// specify the reloc address. This may be NULL if the reloc
// address is absolute.
: rel_(gsym, type, od, address, is_relative), addend_(addend)
{ }
- Output_reloc(Symbol* gsym, unsigned int type, Relobj* relobj,
+ Output_reloc(Symbol* gsym, unsigned int type,
+ Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address, Addend addend,
bool is_relative)
: rel_(gsym, type, relobj, shndx, address, is_relative), addend_(addend)
: rel_(os, type, od, address), addend_(addend)
{ }
- Output_reloc(Output_section* os, unsigned int type, Relobj* relobj,
+ Output_reloc(Output_section* os, unsigned int type,
+ Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address, Addend addend)
: rel_(os, type, relobj, shndx, address), addend_(addend)
{ }
void
write(unsigned char* pov) const;
+ // Return whether this reloc should be sorted before the argument
+ // when sorting dynamic relocs.
+ bool
+ sort_before(const Output_reloc<elfcpp::SHT_RELA, dynamic, size, big_endian>&
+ r2) const
+ {
+ int i = this->rel_.compare(r2.rel_);
+ if (i < 0)
+ return true;
+ else if (i > 0)
+ return false;
+ else
+ return this->addend_ < r2.addend_;
+ }
+
private:
// The basic reloc.
Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian> rel_;
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))
+ Output_data_reloc_base(bool sort_relocs)
+ : Output_section_data_build(Output_data::default_alignment_for_size(size)),
+ sort_relocs_(sort_relocs)
{ }
protected:
void
do_adjust_output_section(Output_section *os);
+ // Write to a map file.
+ void
+ do_print_to_mapfile(Mapfile* mapfile) const
+ {
+ mapfile->print_output_data(this,
+ (dynamic
+ ? _("** dynamic relocs")
+ : _("** relocs")));
+ }
+
// Add a relocation entry.
void
add(Output_data *od, const Output_reloc_type& reloc)
private:
typedef std::vector<Output_reloc_type> Relocs;
+ // The class used to sort the relocations.
+ struct Sort_relocs_comparison
+ {
+ bool
+ operator()(const Output_reloc_type& r1, const Output_reloc_type& r2) const
+ { return r1.sort_before(r2); }
+ };
+
+ // The relocations in this section.
Relocs relocs_;
+ // Whether to sort the relocations when writing them out, to make
+ // the dynamic linker more efficient.
+ bool sort_relocs_;
};
// The class which callers actually create.
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>()
+ Output_data_reloc(bool sr)
+ : Output_data_reloc_base<elfcpp::SHT_REL, dynamic, size, big_endian>(sr)
{ }
// Add a reloc against a global symbol.
{ this->add(od, Output_reloc_type(gsym, type, od, address, false)); }
void
- add_global(Symbol* gsym, unsigned int type, Output_data* od, Relobj* relobj,
+ add_global(Symbol* gsym, unsigned int type, Output_data* od,
+ Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address)
{ this->add(od, Output_reloc_type(gsym, type, relobj, shndx, address,
false)); }
}
void
- add_global(Symbol* gsym, unsigned int type, Output_data* od, Relobj* relobj,
+ add_global(Symbol* gsym, unsigned int type, Output_data* od,
+ Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address, Address addend)
{
gold_assert(addend == 0);
void
add_global_relative(Symbol* gsym, unsigned int type, Output_data* od,
- Relobj* relobj, unsigned int shndx, Address address)
+ Sized_relobj<size, big_endian>* relobj,
+ unsigned int shndx, Address address)
{
this->add(od, Output_reloc_type(gsym, type, relobj, shndx, address,
true));
void
add_output_section(Output_section* os, unsigned int type, Output_data* od,
- Relobj* relobj, unsigned int shndx, Address address)
+ Sized_relobj<size, big_endian>* relobj,
+ unsigned int shndx, Address address)
{ this->add(od, Output_reloc_type(os, type, relobj, shndx, address)); }
};
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>()
+ Output_data_reloc(bool sr)
+ : Output_data_reloc_base<elfcpp::SHT_RELA, dynamic, size, big_endian>(sr)
{ }
// Add a reloc against a global symbol.
false)); }
void
- add_global(Symbol* gsym, unsigned int type, Output_data* od, Relobj* relobj,
+ add_global(Symbol* gsym, unsigned int type, Output_data* od,
+ Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address,
Addend addend)
{ this->add(od, Output_reloc_type(gsym, type, relobj, shndx, address,
void
add_global_relative(Symbol* gsym, unsigned int type, Output_data* od,
- Relobj* relobj, unsigned int shndx, Address address,
- Addend addend)
+ Sized_relobj<size, big_endian>* relobj,
+ unsigned int shndx, Address address, Addend addend)
{ this->add(od, Output_reloc_type(gsym, type, relobj, shndx, address,
addend, true)); }
{ this->add(os, Output_reloc_type(os, type, od, address, addend)); }
void
- add_output_section(Output_section* os, unsigned int type, Relobj* relobj,
+ add_output_section(Output_section* os, unsigned int type,
+ Sized_relobj<size, big_endian>* relobj,
unsigned int shndx, Address address, Addend addend)
{ this->add(os, Output_reloc_type(os, type, relobj, shndx, address,
addend)); }
do_write(Output_file*)
{ }
+ // Write to a map file.
+ void
+ do_print_to_mapfile(Mapfile* mapfile) const
+ { mapfile->print_output_data(this, _("** relocs")); }
+
private:
// The relocs associated with this input section.
Relocatable_relocs* rr_;
class Output_data_group : public Output_section_data
{
public:
+ // The constructor clears *INPUT_SHNDXES.
Output_data_group(Sized_relobj<size, big_endian>* relobj,
section_size_type entry_count,
- const elfcpp::Elf_Word* contents);
+ elfcpp::Elf_Word flags,
+ std::vector<unsigned int>* input_shndxes);
void
do_write(Output_file*);
+ // Write to a map file.
+ void
+ do_print_to_mapfile(Mapfile* mapfile) const
+ { mapfile->print_output_data(this, _("** group")); }
+
+ // Set final data size.
+ void
+ set_final_data_size()
+ { this->set_data_size((this->input_shndxes_.size() + 1) * 4); }
+
private:
// The input object.
Sized_relobj<size, big_endian>* relobj_;
// The group flag word.
elfcpp::Elf_Word flags_;
// The section indexes of the input sections in this group.
- std::vector<unsigned int> input_sections_;
+ std::vector<unsigned int> input_shndxes_;
};
// Output_data_got is used to manage a GOT. Each entry in the GOT is
void
do_write(Output_file*);
+ // Write to a map file.
+ void
+ do_print_to_mapfile(Mapfile* mapfile) const
+ { mapfile->print_output_data(this, _("** GOT")); }
+
private:
// This POD class holds a single GOT entry.
class Got_entry
void
do_write(Output_file*);
+ // Write to a map file.
+ void
+ do_print_to_mapfile(Mapfile* mapfile) const
+ { mapfile->print_output_data(this, _("** dynamic")); }
+
private:
// This POD class holds a single dynamic entry.
class Dynamic_entry
: tag_(tag), offset_(DYNAMIC_STRING)
{ this->u_.str = str; }
+ // Return the tag of this entry.
+ elfcpp::DT
+ tag() const
+ { return this->tag_; }
+
// Write the dynamic entry to an output view.
template<int size, bool big_endian>
void
Stringpool* pool_;
};
+// Output_symtab_xindex is used to handle SHT_SYMTAB_SHNDX sections,
+// which may be required if the object file has more than
+// SHN_LORESERVE sections.
+
+class Output_symtab_xindex : public Output_section_data
+{
+ public:
+ Output_symtab_xindex(size_t symcount)
+ : Output_section_data(symcount * 4, 4, true),
+ entries_()
+ { }
+
+ // Add an entry: symbol number SYMNDX has section SHNDX.
+ void
+ add(unsigned int symndx, unsigned int shndx)
+ { this->entries_.push_back(std::make_pair(symndx, shndx)); }
+
+ protected:
+ void
+ do_write(Output_file*);
+
+ // Write to a map file.
+ void
+ do_print_to_mapfile(Mapfile* mapfile) const
+ { mapfile->print_output_data(this, _("** symtab xindex")); }
+
+ private:
+ template<bool big_endian>
+ void
+ endian_do_write(unsigned char*);
+
+ // It is likely that most symbols will not require entries. Rather
+ // than keep a vector for all symbols, we keep pairs of symbol index
+ // and section index.
+ typedef std::vector<std::pair<unsigned int, unsigned int> > Xindex_entries;
+
+ // The entries we need.
+ Xindex_entries entries_;
+};
+
+// A relaxed input section.
+class Output_relaxed_input_section : public Output_section_data_build
+{
+ public:
+ // We would like to call relobj->section_addralign(shndx) to get the
+ // alignment but we do not want the constructor to fail. So callers
+ // are repsonsible for ensuring that.
+ Output_relaxed_input_section(Relobj* relobj, unsigned int shndx,
+ uint64_t addralign)
+ : Output_section_data_build(addralign), relobj_(relobj), shndx_(shndx)
+ { }
+
+ // Return the Relobj of this relaxed input section.
+ Relobj*
+ relobj() const
+ { return this->relobj_; }
+
+ // Return the section index of this relaxed input section.
+ unsigned int
+ shndx() const
+ { return this->shndx_; }
+
+ private:
+ Relobj* relobj_;
+ unsigned int shndx_;
+};
+
// 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.
// 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
+ // which applies to this section, or 0 if none, or -1 if more than
// one. HAVE_SECTIONS_SCRIPT is true if we have a SECTIONS clause
// in a linker script; in that case we need to keep track of input
// sections associated with an output section. Return the offset
void
add_output_section_data(Output_section_data* posd);
+ // Add a relaxed input section PORIS to this output section.
+ void
+ add_relaxed_input_section(Output_relaxed_input_section* poris);
+
// Return the section name.
const char*
name() const
flags() const
{ return this->flags_; }
- // Set the section flags. This may only be used with the Layout
- // code when it is prepared to move the section to a different
- // segment.
- void
- set_flags(elfcpp::Elf_Xword flags)
- { this->flags_ = flags; }
-
// Update the output section flags based on input section flags.
void
- update_flags_for_input_section(elfcpp::Elf_Xword flags)
- {
- this->flags_ |= (flags
- & (elfcpp::SHF_WRITE
- | elfcpp::SHF_ALLOC
- | elfcpp::SHF_EXECINSTR));
- }
+ update_flags_for_input_section(elfcpp::Elf_Xword flags);
// Return the entsize field.
uint64_t
set_addralign(uint64_t v)
{ this->addralign_ = v; }
+ // Whether the output section index has been set.
+ bool
+ has_out_shndx() const
+ { return this->out_shndx_ != -1U; }
+
// Indicate that we need a symtab index.
void
set_needs_symtab_index()
set_must_sort_attached_input_sections()
{ this->must_sort_attached_input_sections_ = true; }
+ // Return whether this section holds relro data--data which has
+ // dynamic relocations but which may be marked read-only after the
+ // dynamic relocations have been completed.
+ bool
+ is_relro() const
+ { return this->is_relro_; }
+
+ // Record that this section holds relro data.
+ void
+ set_is_relro()
+ { this->is_relro_ = true; }
+
+ // Record that this section does not hold relro data.
+ void
+ clear_is_relro()
+ { this->is_relro_ = false; }
+
+ // True if this section holds relro local data--relro data for which
+ // the dynamic relocations are all RELATIVE relocations.
+ bool
+ is_relro_local() const
+ { return this->is_relro_local_; }
+
+ // Record that this section holds relro local data.
+ void
+ set_is_relro_local()
+ { this->is_relro_local_ = true; }
+
+ // True if this is a small section: a section which holds small
+ // variables.
+ bool
+ is_small_section() const
+ { return this->is_small_section_; }
+
+ // Record that this is a small section.
+ void
+ set_is_small_section()
+ { this->is_small_section_ = true; }
+
+ // True if this is a large section: a section which holds large
+ // variables.
+ bool
+ is_large_section() const
+ { return this->is_large_section_; }
+
+ // Record that this is a large section.
+ void
+ set_is_large_section()
+ { this->is_large_section_ = true; }
+
+ // True if this is a large data (not BSS) section.
+ bool
+ is_large_data_section()
+ { return this->is_large_section_ && this->type_ != elfcpp::SHT_NOBITS; }
+
// Return whether this section should be written after all the input
// sections are complete.
bool
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;
+ // Look for the merged section for input section SHNDX in object
+ // OBJECT. If found, return true, and set *ADDR to the address of
+ // the start of the merged section. This is not necessary the
+ // output offset corresponding to input offset 0 in the section,
+ // since the section may be mapped arbitrarily.
+ bool
+ find_starting_output_address(const Relobj* object, unsigned int shndx,
+ uint64_t* addr) const;
// Record that this output section was found in the SECTIONS clause
// of a linker script.
// The next few calls are for linker script support.
+ // We need to export the input sections to linker scripts. Previously
+ // we export a pair of Relobj pointer and section index. We now need to
+ // handle relaxed input sections as well. So we use this class.
+ class Simple_input_section
+ {
+ private:
+ static const unsigned int invalid_shndx = static_cast<unsigned int>(-1);
+
+ public:
+ Simple_input_section(Relobj *relobj, unsigned int shndx)
+ : shndx_(shndx)
+ {
+ gold_assert(shndx != invalid_shndx);
+ this->u_.relobj = relobj;
+ }
+
+ Simple_input_section(Output_relaxed_input_section* section)
+ : shndx_(invalid_shndx)
+ { this->u_.relaxed_input_section = section; }
+
+ // Whether this is a relaxed section.
+ bool
+ is_relaxed_input_section() const
+ { return this->shndx_ == invalid_shndx; }
+
+ // Return object of an input section.
+ Relobj*
+ relobj() const
+ {
+ return ((this->shndx_ != invalid_shndx)
+ ? this->u_.relobj
+ : this->u_.relaxed_input_section->relobj());
+ }
+
+ // Return index of an input section.
+ unsigned int
+ shndx() const
+ {
+ return ((this->shndx_ != invalid_shndx)
+ ? this->shndx_
+ : this->u_.relaxed_input_section->shndx());
+ }
+
+ // Return the Output_relaxed_input_section object of a relaxed section.
+ Output_relaxed_input_section*
+ relaxed_input_section() const
+ {
+ gold_assert(this->shndx_ == invalid_shndx);
+ return this->u_.relaxed_input_section;
+ }
+
+ private:
+ // Pointer to either an Relobj or an Output_relaxed_input_section.
+ union
+ {
+ Relobj* relobj;
+ Output_relaxed_input_section* relaxed_input_section;
+ } u_;
+ // Section index for an non-relaxed section or invalid_shndx for
+ // a relaxed section.
+ unsigned int shndx_;
+ };
+
// Store the list of input sections for this Output_section into the
// list passed in. This removes the input sections, leaving only
// any Output_section_data elements. This returns the size of those
// any spaces between the remaining Output_section_data elements.
uint64_t
get_input_sections(uint64_t address, const std::string& fill,
- std::list<std::pair<Relobj*, unsigned int > >*);
+ std::list<Simple_input_section>*);
// Add an input section from a script.
void
- add_input_section_for_script(Relobj* object, unsigned int shndx,
+ add_input_section_for_script(const Simple_input_section& input_section,
off_t data_size, uint64_t addralign);
// Set the current size of the output section.
// End of linker script support.
+ // Save states before doing section layout.
+ // This is used for relaxation.
+ void
+ save_states();
+
+ // Restore states prior to section layout.
+ void
+ restore_states();
+
+ // Convert existing input sections to relaxed input sections.
+ void
+ convert_input_sections_to_relaxed_sections(
+ const std::vector<Output_relaxed_input_section*>& sections);
+
+ // Find a relaxed input section to an input section in OBJECT
+ // with index SHNDX. Return NULL if none is found.
+ const Output_section_data*
+ find_relaxed_input_section(const Relobj* object, unsigned int shndx) const;
+
// Print merge statistics to stderr.
void
print_merge_stats();
void
do_reset_address_and_file_offset();
+ // Return true if address and file offset already have reset values. In
+ // other words, calling reset_address_and_file_offset will not change them.
+ bool
+ do_address_and_file_offset_have_reset_values() const;
+
// Write the data to the file. For a typical Output_section, this
// does nothing: the data is written out by calling Object::Relocate
// on each input object. But if there are any Output_section_data
do_finalize_name(Layout*)
{ }
+ // Print to the map file.
+ virtual void
+ do_print_to_mapfile(Mapfile*) const;
+
// Record that this section requires postprocessing after all
// relocations have been applied. This is called by a child class.
void
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
{
gold_assert(shndx != OUTPUT_SECTION_CODE
&& shndx != MERGE_DATA_SECTION_CODE
- && shndx != MERGE_STRING_SECTION_CODE);
+ && shndx != MERGE_STRING_SECTION_CODE
+ && shndx != RELAXED_INPUT_SECTION_CODE);
this->u1_.data_size = data_size;
this->u2_.object = object;
}
// For a non-merge output section.
Input_section(Output_section_data* posd)
- : shndx_(OUTPUT_SECTION_CODE),
- p2align_(ffsll(static_cast<long long>(posd->addralign())))
+ : shndx_(OUTPUT_SECTION_CODE), p2align_(0)
{
this->u1_.data_size = 0;
this->u2_.posd = posd;
: shndx_(is_string
? MERGE_STRING_SECTION_CODE
: MERGE_DATA_SECTION_CODE),
- p2align_(ffsll(static_cast<long long>(posd->addralign())))
+ p2align_(0)
{
this->u1_.entsize = entsize;
this->u2_.posd = posd;
}
+ // For a relaxed input section.
+ Input_section(Output_relaxed_input_section *psection)
+ : shndx_(RELAXED_INPUT_SECTION_CODE), p2align_(0)
+ {
+ this->u1_.data_size = 0;
+ this->u2_.poris = psection;
+ }
+
// The required alignment.
uint64_t
addralign() const
{
+ if (!this->is_input_section())
+ return this->u2_.posd->addralign();
return (this->p2align_ == 0
? 0
: static_cast<uint64_t>(1) << (this->p2align_ - 1));
{
return (this->shndx_ != OUTPUT_SECTION_CODE
&& this->shndx_ != MERGE_DATA_SECTION_CODE
- && this->shndx_ != MERGE_STRING_SECTION_CODE);
+ && this->shndx_ != MERGE_STRING_SECTION_CODE
+ && this->shndx_ != RELAXED_INPUT_SECTION_CODE);
}
// Return whether this is a merge section which matches the
&& this->addralign() == addralign);
}
+ // Return whether this is a relaxed input section.
+ bool
+ is_relaxed_input_section() const
+ { return this->shndx_ == RELAXED_INPUT_SECTION_CODE; }
+
+ // Return whether this is a generic Output_section_data.
+ bool
+ is_output_section_data() const
+ {
+ return this->shndx_ == OUTPUT_SECTION_CODE;
+ }
+
// Return the object for an input section.
Relobj*
relobj() const
{
- gold_assert(this->is_input_section());
- return this->u2_.object;
+ if (this->is_input_section())
+ return this->u2_.object;
+ else if (this->is_relaxed_input_section())
+ return this->u2_.poris->relobj();
+ else
+ gold_unreachable();
}
// Return the input section index for an input section.
unsigned int
shndx() const
{
- gold_assert(this->is_input_section());
- return this->shndx_;
+ if (this->is_input_section())
+ return this->shndx_;
+ else if (this->is_relaxed_input_section())
+ return this->u2_.poris->shndx();
+ else
+ gold_unreachable();
+ }
+
+ // For non-input-sections, return the associated Output_section_data
+ // object.
+ Output_section_data*
+ output_section_data() const
+ {
+ gold_assert(!this->is_input_section());
+ return this->u2_.posd;
+ }
+
+ // Return the Output_relaxed_input_section object.
+ Output_relaxed_input_section*
+ relaxed_input_section() const
+ {
+ gold_assert(this->is_relaxed_input_section());
+ return this->u2_.poris;
}
// Set the output section.
set_output_section(Output_section* os)
{
gold_assert(!this->is_input_section());
- this->u2_.posd->set_output_section(os);
+ Output_section_data *posd =
+ this->is_relaxed_input_section() ? this->u2_.poris : this->u2_.posd;
+ posd->set_output_section(os);
}
// Set the address and file offset. This is called during
void
write_to_buffer(unsigned char*);
+ // Print to a map file.
+ void
+ print_to_mapfile(Mapfile*) const;
+
// Print statistics about merge sections to stderr.
void
print_merge_stats(const char* section_name)
MERGE_DATA_SECTION_CODE = -2U,
// An Output_section_data for an SHF_MERGE section with
// SHF_STRINGS set.
- MERGE_STRING_SECTION_CODE = -3U
+ MERGE_STRING_SECTION_CODE = -3U,
+ // An Output_section_data for a relaxed input section.
+ RELAXED_INPUT_SECTION_CODE = -4U
};
// For an ordinary input section, this is the section index in the
{
// 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
+ // For OUTPUT_SECTION_CODE or RELAXED_INPUT_SECTION_CODE, this is not
+ // used. For MERGE_DATA_SECTION_CODE or MERGE_STRING_SECTION_CODE, the
// entity size.
uint64_t entsize;
} u1_;
// For OUTPUT_SECTION_CODE or MERGE_DATA_SECTION_CODE or
// MERGE_STRING_SECTION_CODE, the data.
Output_section_data* posd;
+ // For RELAXED_INPUT_SECTION_CODE, the data.
+ Output_relaxed_input_section* poris;
} u2_;
};
typedef std::vector<Input_section> Input_section_list;
+ // Allow a child class to access the input sections.
+ const Input_section_list&
+ input_sections() const
+ { return this->input_sections_; }
+
+ private:
+ // We only save enough information to undo the effects of section layout.
+ class Checkpoint_output_section
+ {
+ public:
+ Checkpoint_output_section(uint64_t addralign, elfcpp::Elf_Xword flags,
+ const Input_section_list& input_sections,
+ off_t first_input_offset,
+ bool attached_input_sections_are_sorted)
+ : addralign_(addralign), flags_(flags),
+ input_sections_(input_sections),
+ input_sections_size_(input_sections_.size()),
+ input_sections_copy_(), first_input_offset_(first_input_offset),
+ attached_input_sections_are_sorted_(attached_input_sections_are_sorted)
+ { }
+
+ virtual
+ ~Checkpoint_output_section()
+ { }
+
+ // Return the address alignment.
+ uint64_t
+ addralign() const
+ { return this->addralign_; }
+
+ // Return the section flags.
+ elfcpp::Elf_Xword
+ flags() const
+ { return this->flags_; }
+
+ // Return a reference to the input section list copy.
+ Input_section_list*
+ input_sections()
+ { return &this->input_sections_copy_; }
+
+ // Return the size of input_sections at the time when checkpoint is
+ // taken.
+ size_t
+ input_sections_size() const
+ { return this->input_sections_size_; }
+
+ // Whether input sections are copied.
+ bool
+ input_sections_saved() const
+ { return this->input_sections_copy_.size() == this->input_sections_size_; }
+
+ off_t
+ first_input_offset() const
+ { return this->first_input_offset_; }
+
+ bool
+ attached_input_sections_are_sorted() const
+ { return this->attached_input_sections_are_sorted_; }
+
+ // Save input sections.
+ void
+ save_input_sections()
+ {
+ this->input_sections_copy_.reserve(this->input_sections_size_);
+ this->input_sections_copy_.clear();
+ Input_section_list::const_iterator p = this->input_sections_.begin();
+ gold_assert(this->input_sections_size_ >= this->input_sections_.size());
+ for(size_t i = 0; i < this->input_sections_size_ ; i++, ++p)
+ this->input_sections_copy_.push_back(*p);
+ }
+
+ private:
+ // The section alignment.
+ uint64_t addralign_;
+ // The section flags.
+ elfcpp::Elf_Xword flags_;
+ // Reference to the input sections to be checkpointed.
+ const Input_section_list& input_sections_;
+ // Size of the checkpointed portion of input_sections_;
+ size_t input_sections_size_;
+ // Copy of input sections.
+ Input_section_list input_sections_copy_;
+ // The offset of the first entry in input_sections_.
+ off_t first_input_offset_;
+ // True if the input sections attached to this output section have
+ // already been sorted.
+ bool attached_input_sections_are_sorted_;
+ };
+
// This class is used to sort the input sections.
class Input_section_sort_entry;
typedef std::vector<Fill> Fill_list;
+ // This class describes properties of merge data sections. It is used
+ // as a key type for maps.
+ class Merge_section_properties
+ {
+ public:
+ Merge_section_properties(bool is_string, uint64_t entsize,
+ uint64_t addralign)
+ : is_string_(is_string), entsize_(entsize), addralign_(addralign)
+ { }
+
+ // Whether this equals to another Merge_section_properties MSP.
+ bool
+ eq(const Merge_section_properties& msp) const
+ {
+ return ((this->is_string_ == msp.is_string_)
+ && (this->entsize_ == msp.entsize_)
+ && (this->addralign_ == msp.addralign_));
+ }
+
+ // Compute a hash value for this using 64-bit FNV-1a hash.
+ size_t
+ hash_value() const
+ {
+ uint64_t h = 14695981039346656037ULL; // FNV offset basis.
+ uint64_t prime = 1099511628211ULL;
+ h = (h ^ static_cast<uint64_t>(this->is_string_)) * prime;
+ h = (h ^ static_cast<uint64_t>(this->entsize_)) * prime;
+ h = (h ^ static_cast<uint64_t>(this->addralign_)) * prime;
+ return h;
+ }
+
+ // Functors for associative containers.
+ struct equal_to
+ {
+ bool
+ operator()(const Merge_section_properties& msp1,
+ const Merge_section_properties& msp2) const
+ { return msp1.eq(msp2); }
+ };
+
+ struct hash
+ {
+ size_t
+ operator()(const Merge_section_properties& msp) const
+ { return msp.hash_value(); }
+ };
+
+ private:
+ // Whether this merge data section is for strings.
+ bool is_string_;
+ // Entsize of this merge data section.
+ uint64_t entsize_;
+ // Address alignment.
+ uint64_t addralign_;
+ };
+
+ // Map that link Merge_section_properties to Output_merge_base.
+ typedef Unordered_map<Merge_section_properties, Output_merge_base*,
+ Merge_section_properties::hash,
+ Merge_section_properties::equal_to>
+ Merge_section_by_properties_map;
+
+ // Map that link Input_section_specifier to Output_section_data.
+ typedef Unordered_map<Input_section_specifier, Output_section_data*,
+ Input_section_specifier::hash,
+ Input_section_specifier::equal_to>
+ Output_section_data_by_input_section_map;
+
+ // Map used during relaxation of existing sections. This map
+ // an input section specifier to an input section list index.
+ // We assume that Input_section_list is a vector.
+ typedef Unordered_map<Input_section_specifier, size_t,
+ Input_section_specifier::hash,
+ Input_section_specifier::equal_to>
+ Relaxation_map;
+
// Add a new output section by Input_section.
void
add_output_section_data(Input_section*);
void
sort_attached_input_sections();
+ // Find the merge section into which an input section with index SHNDX in
+ // OBJECT has been added. Return NULL if none found.
+ Output_section_data*
+ find_merge_section(const Relobj* object, unsigned int shndx) const;
+
+ // Build a relaxation map.
+ void
+ build_relaxation_map(
+ const Input_section_list& input_sections,
+ size_t limit,
+ Relaxation_map* map) const;
+
+ // Convert input sections in an input section list into relaxed sections.
+ void
+ convert_input_sections_in_list_to_relaxed_sections(
+ const std::vector<Output_relaxed_input_section*>& relaxed_sections,
+ const Relaxation_map& map,
+ Input_section_list* input_sections);
+
// Most of these fields are only valid after layout.
// The name of the section. This will point into a Stringpool.
// True if the input sections attached to this output section have
// already been sorted.
bool attached_input_sections_are_sorted_ : 1;
+ // True if this section holds relro data.
+ bool is_relro_ : 1;
+ // True if this section holds relro local data.
+ bool is_relro_local_ : 1;
+ // True if this is a small section.
+ bool is_small_section_ : 1;
+ // True if this is a large section.
+ bool is_large_section_ : 1;
// For SHT_TLS sections, the offset of this section relative to the base
// of the TLS segment.
uint64_t tls_offset_;
+ // Saved checkpoint.
+ Checkpoint_output_section* checkpoint_;
+ // Map from input sections to merge sections.
+ Output_section_data_by_input_section_map merge_section_map_;
+ // Map from merge section properties to merge_sections;
+ Merge_section_by_properties_map merge_section_by_properties_map_;
+ // Map from input sections to relaxed input sections. This is mutable
+ // beacause it is udpated lazily. We may need to update it in a
+ // const qualified method.
+ mutable Output_section_data_by_input_section_map relaxed_input_section_map_;
+ // Whether relaxed_input_section_map_ is valid.
+ mutable bool is_relaxed_input_section_map_valid_;
+ // Whether code-fills are generated at write.
+ bool generate_code_fills_at_write_;
};
// An output segment. PT_LOAD segments are built from collections of
// output sections. Other segments typically point within PT_LOAD
// segments, and are built directly as needed.
+//
+// NOTE: We want to use the copy constructor for this class. During
+// relaxation, we may try built the segments multiple times. We do
+// that by copying the original segment list before lay-out, doing
+// a trial lay-out and roll-back to the saved copied if we need to
+// to the lay-out again.
class Output_segment
{
offset() const
{ return this->offset_; }
+ // Whether this is a segment created to hold large data sections.
+ bool
+ is_large_data_segment() const
+ { return this->is_large_data_segment_; }
+
+ // Record that this is a segment created to hold large data
+ // sections.
+ void
+ set_is_large_data_segment()
+ { this->is_large_data_segment_ = true; }
+
// Return the maximum alignment of the Output_data.
uint64_t
maximum_alignment();
// 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_output_section(Output_section* os, elfcpp::Elf_Word seg_flags);
// Remove an Output_section from this segment. It is an error if it
// is not present.
write_section_headers(const Layout*, const Stringpool*, unsigned char* v,
unsigned int* pshndx) const;
- private:
- Output_segment(const Output_segment&);
- Output_segment& operator=(const Output_segment&);
+ // Print the output sections in the map file.
+ void
+ print_sections_to_mapfile(Mapfile*) const;
+ private:
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_list(const Output_data_list*);
+ // Return whether the first data section is a relro section.
+ bool
+ is_first_section_relro() const;
+
// Set the section addresses in an Output_data_list.
uint64_t
set_section_list_addresses(const Layout*, bool reset, Output_data_list*,
uint64_t addr, off_t* poff, unsigned int* pshndx,
- bool* in_tls);
+ bool* in_tls, bool* in_relro);
// Return the number of Output_sections in an Output_data_list.
unsigned int
const Output_data_list*, unsigned char* v,
unsigned int* pshdx) const;
+ // Print a section list to the mapfile.
+ void
+ print_section_list_to_mapfile(Mapfile*, const Output_data_list*) const;
+
+ // NOTE: We want to use the copy constructor. Currently, shallow copy
+ // works for us so we do not need to write our own copy constructor.
+
// The list of output data with contents attached to this segment.
Output_data_list output_data_;
// The list of output data without contents attached to this segment.
bool is_max_align_known_ : 1;
// Whether vaddr and paddr were set by a linker script.
bool are_addresses_set_ : 1;
+ // Whether this segment holds large data sections.
+ bool is_large_data_segment_ : 1;
};
// This class represents the output file.
set_is_temporary()
{ this->is_temporary_ = true; }
+ // Try to open an existing file. Returns false if the file doesn't
+ // exist, has a size of 0 or can't be mmaped. This method is
+ // thread-unsafe.
+ bool
+ open_for_modification();
+
// Open the output file. FILE_SIZE is the final size of the file.
+ // If the file already exists, it is deleted/truncated. This method
+ // is thread-unsafe.
void
open(off_t file_size);
- // Resize the output file.
+ // Resize the output file. This method is thread-unsafe.
void
resize(off_t file_size);
// Close the output file (flushing all buffered data) and make sure
- // there are no errors.
+ // there are no errors. This method is thread-unsafe.
void
close();
+ // Return the size of this file.
+ off_t
+ filesize()
+ { return this->file_size_; }
+
// We currently always use mmap which makes the view handling quite
// simple. In the future we may support other approaches.
{ }
private:
- // Map the file into memory and return a pointer to the map.
+ // Map the file into memory or, if that fails, allocate anonymous
+ // memory.
void
map();
+ // Allocate anonymous memory for the file.
+ bool
+ map_anonymous();
+
+ // Map the file into memory.
+ bool
+ map_no_anonymous();
+
// Unmap the file from memory (and flush to disk buffers).
void
unmap();