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// layout.h -- lay out output file sections for gold -*- C++ -*-
// Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or
// (at your option) any later version.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
// MA 02110-1301, USA.
#ifndef GOLD_LAYOUT_H
#define GOLD_LAYOUT_H
#include <cstring>
#include <list>
#include <map>
#include <string>
#include <utility>
#include <vector>
#include "script.h"
#include "workqueue.h"
#include "object.h"
#include "dynobj.h"
#include "stringpool.h"
namespace gold
{
class General_options;
class Incremental_inputs;
class Input_objects;
class Mapfile;
class Symbol_table;
class Output_section_data;
class Output_section;
class Output_section_headers;
class Output_segment_headers;
class Output_file_header;
class Output_segment;
class Output_data;
class Output_data_reloc_generic;
class Output_data_dynamic;
class Output_symtab_xindex;
class Output_reduced_debug_abbrev_section;
class Output_reduced_debug_info_section;
class Eh_frame;
class Target;
// Return TRUE if SECNAME is the name of a compressed debug section.
extern bool
is_compressed_debug_section(const char* secname);
// This task function handles mapping the input sections to output
// sections and laying them out in memory.
class Layout_task_runner : public Task_function_runner
{
public:
// OPTIONS is the command line options, INPUT_OBJECTS is the list of
// input objects, SYMTAB is the symbol table, LAYOUT is the layout
// object.
Layout_task_runner(const General_options& options,
const Input_objects* input_objects,
Symbol_table* symtab,
Target* target,
Layout* layout,
Mapfile* mapfile)
: options_(options), input_objects_(input_objects), symtab_(symtab),
target_(target), layout_(layout), mapfile_(mapfile)
{ }
// Run the operation.
void
run(Workqueue*, const Task*);
private:
Layout_task_runner(const Layout_task_runner&);
Layout_task_runner& operator=(const Layout_task_runner&);
const General_options& options_;
const Input_objects* input_objects_;
Symbol_table* symtab_;
Target* target_;
Layout* layout_;
Mapfile* mapfile_;
};
// This class holds information about the comdat group or
// .gnu.linkonce section that will be kept for a given signature.
class Kept_section
{
private:
// For a comdat group, we build a mapping from the name of each
// section in the group to the section index and the size in object.
// When we discard a group in some other object file, we use this
// map to figure out which kept section the discarded section is
// associated with. We then use that mapping when processing relocs
// against discarded sections.
struct Comdat_section_info
{
// The section index.
unsigned int shndx;
// The section size.
uint64_t size;
Comdat_section_info(unsigned int a_shndx, uint64_t a_size)
: shndx(a_shndx), size(a_size)
{ }
};
// Most comdat groups have only one or two sections, so we use a
// std::map rather than an Unordered_map to optimize for that case
// without paying too heavily for groups with more sections.
typedef std::map<std::string, Comdat_section_info> Comdat_group;
public:
Kept_section()
: object_(NULL), shndx_(0), is_comdat_(false), is_group_name_(false)
{ this->u_.linkonce_size = 0; }
// We need to support copies for the signature map in the Layout
// object, but we should never copy an object after it has been
// marked as a comdat section.
Kept_section(const Kept_section& k)
: object_(k.object_), shndx_(k.shndx_), is_comdat_(false),
is_group_name_(k.is_group_name_)
{
gold_assert(!k.is_comdat_);
this->u_.linkonce_size = 0;
}
~Kept_section()
{
if (this->is_comdat_)
delete this->u_.group_sections;
}
// The object where this section lives.
Relobj*
object() const
{ return this->object_; }
// Set the object.
void
set_object(Relobj* object)
{
gold_assert(this->object_ == NULL);
this->object_ = object;
}
// The section index.
unsigned int
shndx() const
{ return this->shndx_; }
// Set the section index.
void
set_shndx(unsigned int shndx)
{
gold_assert(this->shndx_ == 0);
this->shndx_ = shndx;
}
// Whether this is a comdat group.
bool
is_comdat() const
{ return this->is_comdat_; }
// Set that this is a comdat group.
void
set_is_comdat()
{
gold_assert(!this->is_comdat_);
this->is_comdat_ = true;
this->u_.group_sections = new Comdat_group();
}
// Whether this is associated with the name of a group or section
// rather than the symbol name derived from a linkonce section.
bool
is_group_name() const
{ return this->is_group_name_; }
// Note that this represents a comdat group rather than a single
// linkonce section.
void
set_is_group_name()
{ this->is_group_name_ = true; }
// Add a section to the group list.
void
add_comdat_section(const std::string& name, unsigned int shndx,
uint64_t size)
{
gold_assert(this->is_comdat_);
Comdat_section_info sinfo(shndx, size);
this->u_.group_sections->insert(std::make_pair(name, sinfo));
}
// Look for a section name in the group list, and return whether it
// was found. If found, returns the section index and size.
bool
find_comdat_section(const std::string& name, unsigned int *pshndx,
uint64_t *psize) const
{
gold_assert(this->is_comdat_);
Comdat_group::const_iterator p = this->u_.group_sections->find(name);
if (p == this->u_.group_sections->end())
return false;
*pshndx = p->second.shndx;
*psize = p->second.size;
return true;
}
// If there is only one section in the group list, return true, and
// return the section index and size.
bool
find_single_comdat_section(unsigned int *pshndx, uint64_t *psize) const
{
gold_assert(this->is_comdat_);
if (this->u_.group_sections->size() != 1)
return false;
Comdat_group::const_iterator p = this->u_.group_sections->begin();
*pshndx = p->second.shndx;
*psize = p->second.size;
return true;
}
// Return the size of a linkonce section.
uint64_t
linkonce_size() const
{
gold_assert(!this->is_comdat_);
return this->u_.linkonce_size;
}
// Set the size of a linkonce section.
void
set_linkonce_size(uint64_t size)
{
gold_assert(!this->is_comdat_);
this->u_.linkonce_size = size;
}
private:
// No assignment.
Kept_section& operator=(const Kept_section&);
// The object containing the comdat group or .gnu.linkonce section.
Relobj* object_;
// Index of the group section for comdats and the section itself for
// .gnu.linkonce.
unsigned int shndx_;
// True if this is for a comdat group rather than a .gnu.linkonce
// section.
bool is_comdat_;
// The Kept_sections are values of a mapping, that maps names to
// them. This field is true if this struct is associated with the
// name of a comdat or .gnu.linkonce, false if it is associated with
// the name of a symbol obtained from the .gnu.linkonce.* name
// through some heuristics.
bool is_group_name_;
union
{
// If the is_comdat_ field is true, this holds a map from names of
// the sections in the group to section indexes in object_ and to
// section sizes.
Comdat_group* group_sections;
// If the is_comdat_ field is false, this holds the size of the
// single section.
uint64_t linkonce_size;
} u_;
};
// This class handles the details of laying out input sections.
class Layout
{
public:
Layout(int number_of_input_files, Script_options*);
~Layout()
{
delete this->relaxation_debug_check_;
delete this->segment_states_;
}
// Given an input section SHNDX, named NAME, with data in SHDR, from
// the object file OBJECT, return the output section where this
// input section should go. RELOC_SHNDX is the index of a
// relocation section which applies to this section, or 0 if none,
// or -1U if more than one. RELOC_TYPE is the type of the
// relocation section if there is one. Set *OFFSET to the offset
// within the output section.
template<int size, bool big_endian>
Output_section*
layout(Sized_relobj<size, big_endian> *object, unsigned int shndx,
const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
unsigned int reloc_shndx, unsigned int reloc_type, off_t* offset);
unsigned int
find_section_order_index(const std::string&);
void
read_layout_from_file();
// Layout an input reloc section when doing a relocatable link. The
// section is RELOC_SHNDX in OBJECT, with data in SHDR.
// DATA_SECTION is the reloc section to which it refers. RR is the
// relocatable information.
template<int size, bool big_endian>
Output_section*
layout_reloc(Sized_relobj<size, big_endian>* object,
unsigned int reloc_shndx,
const elfcpp::Shdr<size, big_endian>& shdr,
Output_section* data_section,
Relocatable_relocs* rr);
// Layout a group section when doing a relocatable link.
template<int size, bool big_endian>
void
layout_group(Symbol_table* symtab,
Sized_relobj<size, big_endian>* object,
unsigned int group_shndx,
const char* group_section_name,
const char* signature,
const elfcpp::Shdr<size, big_endian>& shdr,
elfcpp::Elf_Word flags,
std::vector<unsigned int>* shndxes);
// Like layout, only for exception frame sections. OBJECT is an
// object file. SYMBOLS is the contents of the symbol table
// section, with size SYMBOLS_SIZE. SYMBOL_NAMES is the contents of
// the symbol name section, with size SYMBOL_NAMES_SIZE. SHNDX is a
// .eh_frame section in OBJECT. SHDR is the section header.
// RELOC_SHNDX is the index of a relocation section which applies to
// this section, or 0 if none, or -1U if more than one. RELOC_TYPE
// is the type of the relocation section if there is one. This
// returns the output section, and sets *OFFSET to the offset.
template<int size, bool big_endian>
Output_section*
layout_eh_frame(Sized_relobj<size, big_endian>* object,
const unsigned char* symbols,
off_t symbols_size,
const unsigned char* symbol_names,
off_t symbol_names_size,
unsigned int shndx,
const elfcpp::Shdr<size, big_endian>& shdr,
unsigned int reloc_shndx, unsigned int reloc_type,
off_t* offset);
// Handle a GNU stack note. This is called once per input object
// file. SEEN_GNU_STACK is true if the object file has a
// .note.GNU-stack section. GNU_STACK_FLAGS is the section flags
// from that section if there was one.
void
layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags);
// Add an Output_section_data to the layout. This is used for
// special sections like the GOT section. IS_DYNAMIC_LINKER_SECTION
// is true for sections which are used by the dynamic linker, such
// as dynamic reloc sections. IS_RELRO is true for relro sections.
// IS_LAST_RELRO is true for the last relro section.
// IS_FIRST_NON_RELRO is true for the first section after the relro
// sections.
Output_section*
add_output_section_data(const char* name, elfcpp::Elf_Word type,
elfcpp::Elf_Xword flags,
Output_section_data*, bool is_dynamic_linker_section,
bool is_relro, bool is_last_relro,
bool is_first_non_relro);
// Increase the size of the relro segment by this much.
void
increase_relro(unsigned int s)
{ this->increase_relro_ += s; }
// Create dynamic sections if necessary.
void
create_initial_dynamic_sections(Symbol_table*);
// Define __start and __stop symbols for output sections.
void
define_section_symbols(Symbol_table*);
// Create automatic note sections.
void
create_notes();
// Create sections for linker scripts.
void
create_script_sections()
{ this->script_options_->create_script_sections(this); }
// Define symbols from any linker script.
void
define_script_symbols(Symbol_table* symtab)
{ this->script_options_->add_symbols_to_table(symtab); }
// Define symbols for group signatures.
void
define_group_signatures(Symbol_table*);
// Return the Stringpool used for symbol names.
const Stringpool*
sympool() const
{ return &this->sympool_; }
// Return the Stringpool used for dynamic symbol names and dynamic
// tags.
const Stringpool*
dynpool() const
{ return &this->dynpool_; }
// Return the symtab_xindex section used to hold large section
// indexes for the normal symbol table.
Output_symtab_xindex*
symtab_xindex() const
{ return this->symtab_xindex_; }
// Return the dynsym_xindex section used to hold large section
// indexes for the dynamic symbol table.
Output_symtab_xindex*
dynsym_xindex() const
{ return this->dynsym_xindex_; }
// Return whether a section is a .gnu.linkonce section, given the
// section name.
static inline bool
is_linkonce(const char* name)
{ return strncmp(name, ".gnu.linkonce", sizeof(".gnu.linkonce") - 1) == 0; }
// Whether we have added an input section.
bool
have_added_input_section() const
{ return this->have_added_input_section_; }
// Return true if a section is a debugging section.
static inline bool
is_debug_info_section(const char* name)
{
// Debugging sections can only be recognized by name.
return (strncmp(name, ".debug", sizeof(".debug") - 1) == 0
|| strncmp(name, ".zdebug", sizeof(".zdebug") - 1) == 0
|| strncmp(name, ".gnu.linkonce.wi.",
sizeof(".gnu.linkonce.wi.") - 1) == 0
|| strncmp(name, ".line", sizeof(".line") - 1) == 0
|| strncmp(name, ".stab", sizeof(".stab") - 1) == 0);
}
// Check if a comdat group or .gnu.linkonce section with the given
// NAME is selected for the link. If there is already a section,
// *KEPT_SECTION is set to point to the signature and the function
// returns false. Otherwise, OBJECT, SHNDX,IS_COMDAT, and
// IS_GROUP_NAME are recorded for this NAME in the layout object,
// *KEPT_SECTION is set to the internal copy and the function return
// false.
bool
find_or_add_kept_section(const std::string& name, Relobj* object,
unsigned int shndx, bool is_comdat,
bool is_group_name, Kept_section** kept_section);
// Finalize the layout after all the input sections have been added.
off_t
finalize(const Input_objects*, Symbol_table*, Target*, const Task*);
// Return whether any sections require postprocessing.
bool
any_postprocessing_sections() const
{ return this->any_postprocessing_sections_; }
// Return the size of the output file.
off_t
output_file_size() const
{ return this->output_file_size_; }
// Return the TLS segment. This will return NULL if there isn't
// one.
Output_segment*
tls_segment() const
{ return this->tls_segment_; }
// Return the normal symbol table.
Output_section*
symtab_section() const
{
gold_assert(this->symtab_section_ != NULL);
return this->symtab_section_;
}
// Return the dynamic symbol table.
Output_section*
dynsym_section() const
{
gold_assert(this->dynsym_section_ != NULL);
return this->dynsym_section_;
}
// Return the dynamic tags.
Output_data_dynamic*
dynamic_data() const
{ return this->dynamic_data_; }
// Write out the output sections.
void
write_output_sections(Output_file* of) const;
// Write out data not associated with an input file or the symbol
// table.
void
write_data(const Symbol_table*, Output_file*) const;
// Write out output sections which can not be written until all the
// input sections are complete.
void
write_sections_after_input_sections(Output_file* of);
// Return an output section named NAME, or NULL if there is none.
Output_section*
find_output_section(const char* name) const;
// Return an output segment of type TYPE, with segment flags SET set
// and segment flags CLEAR clear. Return NULL if there is none.
Output_segment*
find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set,
elfcpp::Elf_Word clear) const;
// Return the number of segments we expect to produce.
size_t
expected_segment_count() const;
// Set a flag to indicate that an object file uses the static TLS model.
void
set_has_static_tls()
{ this->has_static_tls_ = true; }
// Return true if any object file uses the static TLS model.
bool
has_static_tls() const
{ return this->has_static_tls_; }
// Return the options which may be set by a linker script.
Script_options*
script_options()
{ return this->script_options_; }
const Script_options*
script_options() const
{ return this->script_options_; }
// Return the object managing inputs in incremental build. NULL in
// non-incremental builds.
Incremental_inputs*
incremental_inputs()
{ return this->incremental_inputs_; }
// For the target-specific code to add dynamic tags which are common
// to most targets.
void
add_target_dynamic_tags(bool use_rel, const Output_data* plt_got,
const Output_data* plt_rel,
const Output_data_reloc_generic* dyn_rel,
bool add_debug, bool dynrel_includes_plt);
// Compute and write out the build ID if needed.
void
write_build_id(Output_file*) const;
// Rewrite output file in binary format.
void
write_binary(Output_file* in) const;
// Print output sections to the map file.
void
print_to_mapfile(Mapfile*) const;
// Dump statistical information to stderr.
void
print_stats() const;
// A list of segments.
typedef std::vector<Output_segment*> Segment_list;
// A list of sections.
typedef std::vector<Output_section*> Section_list;
// The list of information to write out which is not attached to
// either a section or a segment.
typedef std::vector<Output_data*> Data_list;
// Store the allocated sections into the section list. This is used
// by the linker script code.
void
get_allocated_sections(Section_list*) const;
// Make a section for a linker script to hold data.
Output_section*
make_output_section_for_script(const char* name,
Script_sections::Section_type section_type);
// Make a segment. This is used by the linker script code.
Output_segment*
make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags);
// Return the number of segments.
size_t
segment_count() const
{ return this->segment_list_.size(); }
// Map from section flags to segment flags.
static elfcpp::Elf_Word
section_flags_to_segment(elfcpp::Elf_Xword flags);
// Attach sections to segments.
void
attach_sections_to_segments();
// For relaxation clean up, we need to know output section data created
// from a linker script.
void
new_output_section_data_from_script(Output_section_data* posd)
{
if (this->record_output_section_data_from_script_)
this->script_output_section_data_list_.push_back(posd);
}
// Return section list.
const Section_list&
section_list() const
{ return this->section_list_; }
private:
Layout(const Layout&);
Layout& operator=(const Layout&);
// Mapping from input section names to output section names.
struct Section_name_mapping
{
const char* from;
int fromlen;
const char* to;
int tolen;
};
static const Section_name_mapping section_name_mapping[];
static const int section_name_mapping_count;
// During a relocatable link, a list of group sections and
// signatures.
struct Group_signature
{
// The group section.
Output_section* section;
// The signature.
const char* signature;
Group_signature()
: section(NULL), signature(NULL)
{ }
Group_signature(Output_section* sectiona, const char* signaturea)
: section(sectiona), signature(signaturea)
{ }
};
typedef std::vector<Group_signature> Group_signatures;
// Create a note section, filling in the header.
Output_section*
create_note(const char* name, int note_type, const char *section_name,
size_t descsz, bool allocate, size_t* trailing_padding);
// Create a note section for gold version.
void
create_gold_note();
// Record whether the stack must be executable.
void
create_executable_stack_info();
// Create a build ID note if needed.
void
create_build_id();
// Link .stab and .stabstr sections.
void
link_stabs_sections();
// Create .gnu_incremental_inputs and .gnu_incremental_strtab sections needed
// for the next run of incremental linking to check what has changed.
void
create_incremental_info_sections();
// Find the first read-only PT_LOAD segment, creating one if
// necessary.
Output_segment*
find_first_load_seg();
// Count the local symbols in the regular symbol table and the dynamic
// symbol table, and build the respective string pools.
void
count_local_symbols(const Task*, const Input_objects*);
// Create the output sections for the symbol table.
void
create_symtab_sections(const Input_objects*, Symbol_table*,
unsigned int, off_t*);
// Create the .shstrtab section.
Output_section*
create_shstrtab();
// Create the section header table.
void
create_shdrs(const Output_section* shstrtab_section, off_t*);
// Create the dynamic symbol table.
void
create_dynamic_symtab(const Input_objects*, Symbol_table*,
Output_section** pdynstr,
unsigned int* plocal_dynamic_count,
std::vector<Symbol*>* pdynamic_symbols,
Versions* versions);
// Assign offsets to each local portion of the dynamic symbol table.
void
assign_local_dynsym_offsets(const Input_objects*);
// Finish the .dynamic section and PT_DYNAMIC segment.
void
finish_dynamic_section(const Input_objects*, const Symbol_table*);
// Set the size of the _DYNAMIC symbol.
void
set_dynamic_symbol_size(const Symbol_table*);
// Create the .interp section and PT_INTERP segment.
void
create_interp(const Target* target);
// Create the version sections.
void
create_version_sections(const Versions*,
const Symbol_table*,
unsigned int local_symcount,
const std::vector<Symbol*>& dynamic_symbols,
const Output_section* dynstr);
template<int size, bool big_endian>
void
sized_create_version_sections(const Versions* versions,
const Symbol_table*,
unsigned int local_symcount,
const std::vector<Symbol*>& dynamic_symbols,
const Output_section* dynstr);
// Return whether to include this section in the link.
template<int size, bool big_endian>
bool
include_section(Sized_relobj<size, big_endian>* object, const char* name,
const elfcpp::Shdr<size, big_endian>&);
// Return the output section name to use given an input section
// name. Set *PLEN to the length of the name. *PLEN must be
// initialized to the length of NAME.
static const char*
output_section_name(const char* name, size_t* plen);
// Return the number of allocated output sections.
size_t
allocated_output_section_count() const;
// Return the output section for NAME, TYPE and FLAGS.
Output_section*
get_output_section(const char* name, Stringpool::Key name_key,
elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
bool is_interp, bool is_dynamic_linker_section,
bool is_relro, bool is_last_relro,
bool is_first_non_relro);
// Choose the output section for NAME in RELOBJ.
Output_section*
choose_output_section(const Relobj* relobj, const char* name,
elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
bool is_input_section, bool is_interp,
bool is_dynamic_linker_section, bool is_relro,
bool is_last_relro, bool is_first_non_relro);
// Create a new Output_section.
Output_section*
make_output_section(const char* name, elfcpp::Elf_Word type,
elfcpp::Elf_Xword flags, bool is_interp,
bool is_dynamic_linker_section, bool is_relro,
bool is_last_relro, bool is_first_non_relro);
// Attach a section to a segment.
void
attach_section_to_segment(Output_section*);
// Attach an allocated section to a segment.
void
attach_allocated_section_to_segment(Output_section*);
// Set the final file offsets of all the segments.
off_t
set_segment_offsets(const Target*, Output_segment*, unsigned int* pshndx);
// Set the file offsets of the sections when doing a relocatable
// link.
off_t
set_relocatable_section_offsets(Output_data*, unsigned int* pshndx);
// Set the final file offsets of all the sections not associated
// with a segment. We set section offsets in three passes: the
// first handles all allocated sections, the second sections that
// require postprocessing, and the last the late-bound STRTAB
// sections (probably only shstrtab, which is the one we care about
// because it holds section names).
enum Section_offset_pass
{
BEFORE_INPUT_SECTIONS_PASS,
POSTPROCESSING_SECTIONS_PASS,
STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
};
off_t
set_section_offsets(off_t, Section_offset_pass pass);
// Set the final section indexes of all the sections not associated
// with a segment. Returns the next unused index.
unsigned int
set_section_indexes(unsigned int pshndx);
// Set the section addresses when using a script.
Output_segment*
set_section_addresses_from_script(Symbol_table*);
// Find appropriate places or orphan sections in a script.
void
place_orphan_sections_in_script();
// Return whether SEG1 comes before SEG2 in the output file.
static bool
segment_precedes(const Output_segment* seg1, const Output_segment* seg2);
// Use to save and restore segments during relaxation.
typedef Unordered_map<const Output_segment*, const Output_segment*>
Segment_states;
// Save states of current output segments.
void
save_segments(Segment_states*);
// Restore output segment states.
void
restore_segments(const Segment_states*);
// Clean up after relaxation so that it is possible to lay out the
// sections and segments again.
void
clean_up_after_relaxation();
// Doing preparation work for relaxation. This is factored out to make
// Layout::finalized a bit smaller and easier to read.
void
prepare_for_relaxation();
// Main body of the relaxation loop, which lays out the section.
off_t
relaxation_loop_body(int, Target*, Symbol_table*, Output_segment**,
Output_segment*, Output_segment_headers*,
Output_file_header*, unsigned int*);
// A mapping used for kept comdats/.gnu.linkonce group signatures.
typedef Unordered_map<std::string, Kept_section> Signatures;
// Mapping from input section name/type/flags to output section. We
// use canonicalized strings here.
typedef std::pair<Stringpool::Key,
std::pair<elfcpp::Elf_Word, elfcpp::Elf_Xword> > Key;
struct Hash_key
{
size_t
operator()(const Key& k) const;
};
typedef Unordered_map<Key, Output_section*, Hash_key> Section_name_map;
// A comparison class for segments.
struct Compare_segments
{
bool
operator()(const Output_segment* seg1, const Output_segment* seg2)
{ return Layout::segment_precedes(seg1, seg2); }
};
typedef std::vector<Output_section_data*> Output_section_data_list;
// Debug checker class.
class Relaxation_debug_check
{
public:
Relaxation_debug_check()
: section_infos_()
{ }
// Check that sections and special data are in reset states.
void
check_output_data_for_reset_values(const Layout::Section_list&,
const Layout::Data_list&);
// Record information of a section list.
void
read_sections(const Layout::Section_list&);
// Verify a section list with recorded information.
void
verify_sections(const Layout::Section_list&);
private:
// Information we care about a section.
struct Section_info
{
// Output section described by this.
Output_section* output_section;
// Load address.
uint64_t address;
// Data size.
off_t data_size;
// File offset.
off_t offset;
};
// Section information.
std::vector<Section_info> section_infos_;
};
// The number of input files, for sizing tables.
int number_of_input_files_;
// Information set by scripts or by command line options.
Script_options* script_options_;
// The output section names.
Stringpool namepool_;
// The output symbol names.
Stringpool sympool_;
// The dynamic strings, if needed.
Stringpool dynpool_;
// The list of group sections and linkonce sections which we have seen.
Signatures signatures_;
// The mapping from input section name/type/flags to output sections.
Section_name_map section_name_map_;
// The list of output segments.
Segment_list segment_list_;
// The list of output sections.
Section_list section_list_;
// The list of output sections which are not attached to any output
// segment.
Section_list unattached_section_list_;
// The list of unattached Output_data objects which require special
// handling because they are not Output_sections.
Data_list special_output_list_;
// The section headers.
Output_section_headers* section_headers_;
// A pointer to the PT_TLS segment if there is one.
Output_segment* tls_segment_;
// A pointer to the PT_GNU_RELRO segment if there is one.
Output_segment* relro_segment_;
// A backend may increase the size of the PT_GNU_RELRO segment if
// there is one. This is the amount to increase it by.
unsigned int increase_relro_;
// The SHT_SYMTAB output section.
Output_section* symtab_section_;
// The SHT_SYMTAB_SHNDX for the regular symbol table if there is one.
Output_symtab_xindex* symtab_xindex_;
// The SHT_DYNSYM output section if there is one.
Output_section* dynsym_section_;
// The SHT_SYMTAB_SHNDX for the dynamic symbol table if there is one.
Output_symtab_xindex* dynsym_xindex_;
// The SHT_DYNAMIC output section if there is one.
Output_section* dynamic_section_;
// The _DYNAMIC symbol if there is one.
Symbol* dynamic_symbol_;
// The dynamic data which goes into dynamic_section_.
Output_data_dynamic* dynamic_data_;
// The exception frame output section if there is one.
Output_section* eh_frame_section_;
// The exception frame data for eh_frame_section_.
Eh_frame* eh_frame_data_;
// Whether we have added eh_frame_data_ to the .eh_frame section.
bool added_eh_frame_data_;
// The exception frame header output section if there is one.
Output_section* eh_frame_hdr_section_;
// The space for the build ID checksum if there is one.
Output_section_data* build_id_note_;
// The output section containing dwarf abbreviations
Output_reduced_debug_abbrev_section* debug_abbrev_;
// The output section containing the dwarf debug info tree
Output_reduced_debug_info_section* debug_info_;
// A list of group sections and their signatures.
Group_signatures group_signatures_;
// The size of the output file.
off_t output_file_size_;
// Whether we have added an input section to an output section.
bool have_added_input_section_;
// Whether we have attached the sections to the segments.
bool sections_are_attached_;
// Whether we have seen an object file marked to require an
// executable stack.
bool input_requires_executable_stack_;
// Whether we have seen at least one object file with an executable
// stack marker.
bool input_with_gnu_stack_note_;
// Whether we have seen at least one object file without an
// executable stack marker.
bool input_without_gnu_stack_note_;
// Whether we have seen an object file that uses the static TLS model.
bool has_static_tls_;
// Whether any sections require postprocessing.
bool any_postprocessing_sections_;
// Whether we have resized the signatures_ hash table.
bool resized_signatures_;
// Whether we have created a .stab*str output section.
bool have_stabstr_section_;
// In incremental build, holds information check the inputs and build the
// .gnu_incremental_inputs section.
Incremental_inputs* incremental_inputs_;
// Whether we record output section data created in script
bool record_output_section_data_from_script_;
// List of output data that needs to be removed at relexation clean up.
Output_section_data_list script_output_section_data_list_;
// Structure to save segment states before entering the relaxation loop.
Segment_states* segment_states_;
// A relaxation debug checker. We only create one when in debugging mode.
Relaxation_debug_check* relaxation_debug_check_;
// Hash a pattern to its position in the section ordering file.
Unordered_map<std::string, unsigned int> input_section_position_;
// Vector of glob only patterns in the section_ordering file.
std::vector<std::string> input_section_glob_;
};
// This task handles writing out data in output sections which is not
// part of an input section, or which requires special handling. When
// this is done, it unblocks both output_sections_blocker and
// final_blocker.
class Write_sections_task : public Task
{
public:
Write_sections_task(const Layout* layout, Output_file* of,
Task_token* output_sections_blocker,
Task_token* final_blocker)
: layout_(layout), of_(of),
output_sections_blocker_(output_sections_blocker),
final_blocker_(final_blocker)
{ }
// The standard Task methods.
Task_token*
is_runnable();
void
locks(Task_locker*);
void
run(Workqueue*);
std::string
get_name() const
{ return "Write_sections_task"; }
private:
class Write_sections_locker;
const Layout* layout_;
Output_file* of_;
Task_token* output_sections_blocker_;
Task_token* final_blocker_;
};
// This task handles writing out data which is not part of a section
// or segment.
class Write_data_task : public Task
{
public:
Write_data_task(const Layout* layout, const Symbol_table* symtab,
Output_file* of, Task_token* final_blocker)
: layout_(layout), symtab_(symtab), of_(of), final_blocker_(final_blocker)
{ }
// The standard Task methods.
Task_token*
is_runnable();
void
locks(Task_locker*);
void
run(Workqueue*);
std::string
get_name() const
{ return "Write_data_task"; }
private:
const Layout* layout_;
const Symbol_table* symtab_;
Output_file* of_;
Task_token* final_blocker_;
};
// This task handles writing out the global symbols.
class Write_symbols_task : public Task
{
public:
Write_symbols_task(const Layout* layout, const Symbol_table* symtab,
const Input_objects* input_objects,
const Stringpool* sympool, const Stringpool* dynpool,
Output_file* of, Task_token* final_blocker)
: layout_(layout), symtab_(symtab), input_objects_(input_objects),
sympool_(sympool), dynpool_(dynpool), of_(of),
final_blocker_(final_blocker)
{ }
// The standard Task methods.
Task_token*
is_runnable();
void
locks(Task_locker*);
void
run(Workqueue*);
std::string
get_name() const
{ return "Write_symbols_task"; }
private:
const Layout* layout_;
const Symbol_table* symtab_;
const Input_objects* input_objects_;
const Stringpool* sympool_;
const Stringpool* dynpool_;
Output_file* of_;
Task_token* final_blocker_;
};
// This task handles writing out data in output sections which can't
// be written out until all the input sections have been handled.
// This is for sections whose contents is based on the contents of
// other output sections.
class Write_after_input_sections_task : public Task
{
public:
Write_after_input_sections_task(Layout* layout, Output_file* of,
Task_token* input_sections_blocker,
Task_token* final_blocker)
: layout_(layout), of_(of),
input_sections_blocker_(input_sections_blocker),
final_blocker_(final_blocker)
{ }
// The standard Task methods.
Task_token*
is_runnable();
void
locks(Task_locker*);
void
run(Workqueue*);
std::string
get_name() const
{ return "Write_after_input_sections_task"; }
private:
Layout* layout_;
Output_file* of_;
Task_token* input_sections_blocker_;
Task_token* final_blocker_;
};
// This task function handles closing the file.
class Close_task_runner : public Task_function_runner
{
public:
Close_task_runner(const General_options* options, const Layout* layout,
Output_file* of)
: options_(options), layout_(layout), of_(of)
{ }
// Run the operation.
void
run(Workqueue*, const Task*);
private:
const General_options* options_;
const Layout* layout_;
Output_file* of_;
};
// A small helper function to align an address.
inline uint64_t
align_address(uint64_t address, uint64_t addralign)
{
if (addralign != 0)
address = (address + addralign - 1) &~ (addralign - 1);
return address;
}
} // End namespace gold.
#endif // !defined(GOLD_LAYOUT_H)
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