binutils-gdb/gold/archive.h

576 lines
15 KiB
C++

// archive.h -- archive support for gold -*- C++ -*-
// Copyright (C) 2006-2017 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_ARCHIVE_H
#define GOLD_ARCHIVE_H
#include <string>
#include <vector>
#include "fileread.h"
#include "workqueue.h"
namespace gold
{
class Task;
class Input_argument;
class Input_file;
class Input_objects;
class Input_group;
class Layout;
class Symbol_table;
class Object;
struct Read_symbols_data;
class Input_file_lib;
class Incremental_archive_entry;
// An entry in the archive map of offsets to members.
struct Archive_member
{
Archive_member()
: obj_(NULL), sd_(NULL), arg_serial_(0)
{ }
Archive_member(Object* obj, Read_symbols_data* sd)
: obj_(obj), sd_(sd), arg_serial_(0)
{ }
// The object file.
Object* obj_;
// The data to pass from read_symbols() to add_symbols().
Read_symbols_data* sd_;
// The serial number of the file in the argument list.
unsigned int arg_serial_;
};
// This class serves as a base class for Archive and Lib_group objects.
class Library_base
{
public:
Library_base(Task* task)
: task_(task), incremental_info_(NULL)
{ }
virtual
~Library_base()
{ }
// The file name.
const std::string&
filename() const
{ return this->do_filename(); }
// The modification time of the archive file.
Timespec
get_mtime()
{ return this->do_get_mtime(); }
// When we see a symbol in an archive we might decide to include the member,
// not include the member or be undecided. This enum represents these
// possibilities.
enum Should_include
{
SHOULD_INCLUDE_NO,
SHOULD_INCLUDE_YES,
SHOULD_INCLUDE_UNKNOWN
};
static Should_include
should_include_member(Symbol_table* symtab, Layout*, const char* sym_name,
Symbol** symp, std::string* why, char** tmpbufp,
size_t* tmpbuflen);
// Store a pointer to the incremental link info for the library.
void
set_incremental_info(Incremental_archive_entry* info)
{ this->incremental_info_ = info; }
// Return the pointer to the incremental link info for the library.
Incremental_archive_entry*
incremental_info() const
{ return this->incremental_info_; }
// Abstract base class for processing unused symbols.
class Symbol_visitor_base
{
public:
Symbol_visitor_base()
{ }
virtual
~Symbol_visitor_base()
{ }
// This function will be called for each unused global
// symbol in a library, with a pointer to the symbol name.
virtual void
visit(const char* /* name */) = 0;
};
// Iterator for unused global symbols in the library.
// Calls v->visit() for each global symbol defined
// in each unused library member, passing a pointer to
// the symbol name.
void
for_all_unused_symbols(Symbol_visitor_base* v) const
{ this->do_for_all_unused_symbols(v); }
protected:
// The task reading this archive.
Task *task_;
private:
// The file name.
virtual const std::string&
do_filename() const = 0;
// Return the modification time of the archive file.
virtual Timespec
do_get_mtime() = 0;
// Iterator for unused global symbols in the library.
virtual void
do_for_all_unused_symbols(Symbol_visitor_base* v) const = 0;
// The incremental link information for this archive.
Incremental_archive_entry* incremental_info_;
};
// This class represents an archive--generally a libNAME.a file.
// Archives have a symbol table and a list of objects.
class Archive : public Library_base
{
public:
Archive(const std::string& name, Input_file* input_file,
bool is_thin_archive, Dirsearch* dirpath, Task* task);
// The length of the magic string at the start of an archive.
static const int sarmag = 8;
// The magic string at the start of an archive.
static const char armag[sarmag];
static const char armagt[sarmag];
// The string expected at the end of an archive member header.
static const char arfmag[2];
// Name of 64-bit symbol table member.
static const char sym64name[7];
// The name of the object. This is the name used on the command
// line; e.g., if "-lgcc" is on the command line, this will be
// "gcc".
const std::string&
name() const
{ return this->name_; }
// The input file.
const Input_file*
input_file() const
{ return this->input_file_; }
// Set up the archive: read the symbol map.
void
setup();
// Get a reference to the underlying file.
File_read&
file()
{ return this->input_file_->file(); }
const File_read&
file() const
{ return this->input_file_->file(); }
// Lock the underlying file.
void
lock(const Task* t)
{ this->input_file_->file().lock(t); }
// Unlock the underlying file.
void
unlock(const Task* t)
{ this->input_file_->file().unlock(t); }
// Return whether the underlying file is locked.
bool
is_locked() const
{ return this->input_file_->file().is_locked(); }
// Return the token, so that the task can be queued.
Task_token*
token()
{ return this->input_file_->file().token(); }
// Release the underlying file.
void
release()
{ this->input_file_->file().release(); }
// Clear uncached views in the underlying file.
void
clear_uncached_views()
{ this->input_file_->file().clear_uncached_views(); }
// Whether this is a thin archive.
bool
is_thin_archive() const
{ return this->is_thin_archive_; }
// Unlock any nested archives.
void
unlock_nested_archives();
// Select members from the archive as needed and add them to the
// link.
bool
add_symbols(Symbol_table*, Layout*, Input_objects*, Mapfile*);
// Return whether the archive defines the symbol.
bool
defines_symbol(Symbol*) const;
// Dump statistical information to stderr.
static void
print_stats();
// Return the number of members in the archive.
size_t
count_members();
// Return the no-export flag.
bool
no_export()
{ return this->no_export_; }
private:
Archive(const Archive&);
Archive& operator=(const Archive&);
// The file name.
const std::string&
do_filename() const
{ return this->input_file_->filename(); }
// The modification time of the archive file.
Timespec
do_get_mtime()
{ return this->file().get_mtime(); }
struct Archive_header;
// Total number of archives seen.
static unsigned int total_archives;
// Total number of archive members seen.
static unsigned int total_members;
// Number of archive members loaded.
static unsigned int total_members_loaded;
// Get a view into the underlying file.
const unsigned char*
get_view(off_t start, section_size_type size, bool aligned, bool cache)
{ return this->input_file_->file().get_view(0, start, size, aligned, cache); }
// Read the archive symbol map.
template<int mapsize>
void
read_armap(off_t start, section_size_type size);
// Read an archive member header at OFF. CACHE is whether to cache
// the file view. Return the size of the member, and set *PNAME to
// the name.
off_t
read_header(off_t off, bool cache, std::string* pname, off_t* nested_off);
// Interpret an archive header HDR at OFF. Return the size of the
// member, and set *PNAME to the name.
off_t
interpret_header(const Archive_header* hdr, off_t off, std::string* pname,
off_t* nested_off) const;
// Get the file and offset for an archive member, which may be an
// external member of a thin archive. Set *INPUT_FILE to the
// file containing the actual member, *MEMOFF to the offset
// within that file (0 if not a nested archive), and *MEMBER_NAME
// to the name of the archive member. Return TRUE on success.
bool
get_file_and_offset(off_t off, Input_file** input_file, off_t* memoff,
off_t* memsize, std::string* member_name);
// Return an ELF object for the member at offset OFF.
Object*
get_elf_object_for_member(off_t off, bool*);
// Read the symbols from all the archive members in the link.
void
read_all_symbols();
// Read the symbols from an archive member in the link. OFF is the file
// offset of the member header.
void
read_symbols(off_t off);
// Include all the archive members in the link.
bool
include_all_members(Symbol_table*, Layout*, Input_objects*, Mapfile*);
// Include an archive member in the link.
bool
include_member(Symbol_table*, Layout*, Input_objects*, off_t off,
Mapfile*, Symbol*, const char* why);
// Return whether we found this archive by searching a directory.
bool
searched_for() const
{ return this->input_file_->will_search_for(); }
// Iterate over archive members.
class const_iterator;
const_iterator
begin();
const_iterator
end();
friend class const_iterator;
// Iterator for unused global symbols in the library.
void
do_for_all_unused_symbols(Symbol_visitor_base* v) const;
// An entry in the archive map of symbols to object files.
struct Armap_entry
{
// The offset to the symbol name in armap_names_.
off_t name_offset;
// The file offset to the object in the archive.
off_t file_offset;
};
// A simple hash code for off_t values.
class Seen_hash
{
public:
size_t operator()(off_t val) const
{ return static_cast<size_t>(val); }
};
// For keeping track of open nested archives in a thin archive file.
typedef Unordered_map<std::string, Archive*> Nested_archive_table;
// Name of object as printed to user.
std::string name_;
// For reading the file.
Input_file* input_file_;
// The archive map.
std::vector<Armap_entry> armap_;
// The names in the archive map.
std::string armap_names_;
// The extended name table.
std::string extended_names_;
// Track which symbols in the archive map are for elements which are
// defined or which have already been included in the link.
std::vector<bool> armap_checked_;
// Track which elements have been included by offset.
Unordered_set<off_t, Seen_hash> seen_offsets_;
// Table of objects whose symbols have been pre-read.
std::map<off_t, Archive_member> members_;
// True if this is a thin archive.
const bool is_thin_archive_;
// True if we have included at least one object from this archive.
bool included_member_;
// Table of nested archives, indexed by filename.
Nested_archive_table nested_archives_;
// The directory search path.
Dirsearch* dirpath_;
// Number of members in this archive;
unsigned int num_members_;
// True if we exclude this library archive from automatic export.
bool no_export_;
// True if this library has been included as a --whole-archive.
bool included_all_members_;
};
// This class is used to read an archive and pick out the desired
// elements and add them to the link.
class Add_archive_symbols : public Task
{
public:
Add_archive_symbols(Symbol_table* symtab, Layout* layout,
Input_objects* input_objects, Dirsearch* dirpath,
int dirindex, Mapfile* mapfile,
const Input_argument* input_argument,
Archive* archive, Input_group* input_group,
Task_token* this_blocker,
Task_token* next_blocker)
: symtab_(symtab), layout_(layout), input_objects_(input_objects),
dirpath_(dirpath), dirindex_(dirindex), mapfile_(mapfile),
input_argument_(input_argument), archive_(archive),
input_group_(input_group), this_blocker_(this_blocker),
next_blocker_(next_blocker)
{ }
~Add_archive_symbols();
// The standard Task methods.
Task_token*
is_runnable();
void
locks(Task_locker*);
void
run(Workqueue*);
std::string
get_name() const
{
if (this->archive_ == NULL)
return "Add_archive_symbols";
return "Add_archive_symbols " + this->archive_->file().filename();
}
private:
Symbol_table* symtab_;
Layout* layout_;
Input_objects* input_objects_;
Dirsearch* dirpath_;
int dirindex_;
Mapfile* mapfile_;
const Input_argument* input_argument_;
Archive* archive_;
Input_group* input_group_;
Task_token* this_blocker_;
Task_token* next_blocker_;
};
// This class represents the files surrounded by a --start-lib ... --end-lib.
class Lib_group : public Library_base
{
public:
Lib_group(const Input_file_lib* lib, Task* task);
// Select members from the lib group as needed and add them to the link.
void
add_symbols(Symbol_table*, Layout*, Input_objects*);
// Include a member of the lib group in the link.
void
include_member(Symbol_table*, Layout*, Input_objects*, const Archive_member&);
Archive_member*
get_member(int i)
{
return &this->members_[i];
}
// Total number of archives seen.
static unsigned int total_lib_groups;
// Total number of archive members seen.
static unsigned int total_members;
// Number of archive members loaded.
static unsigned int total_members_loaded;
// Dump statistical information to stderr.
static void
print_stats();
private:
// The file name.
const std::string&
do_filename() const;
// A Lib_group does not have a modification time, since there is no
// real library file.
Timespec
do_get_mtime()
{ return Timespec(0, 0); }
// Iterator for unused global symbols in the library.
void
do_for_all_unused_symbols(Symbol_visitor_base*) const;
// Table of the objects in the group.
std::vector<Archive_member> members_;
};
// This class is used to pick out the desired elements and add them to the link.
class Add_lib_group_symbols : public Task
{
public:
Add_lib_group_symbols(Symbol_table* symtab, Layout* layout,
Input_objects* input_objects,
Lib_group* lib, Task_token* next_blocker)
: symtab_(symtab), layout_(layout), input_objects_(input_objects),
lib_(lib), readsyms_blocker_(NULL), this_blocker_(NULL),
next_blocker_(next_blocker)
{ }
~Add_lib_group_symbols();
// The standard Task methods.
Task_token*
is_runnable();
void
locks(Task_locker*);
void
run(Workqueue*);
// Set the blocker to use for this task.
void
set_blocker(Task_token* readsyms_blocker, Task_token* this_blocker)
{
gold_assert(this->readsyms_blocker_ == NULL && this->this_blocker_ == NULL);
this->readsyms_blocker_ = readsyms_blocker;
this->this_blocker_ = this_blocker;
}
std::string
get_name() const
{
return "Add_lib_group_symbols";
}
private:
Symbol_table* symtab_;
Layout* layout_;
Input_objects* input_objects_;
Lib_group* lib_;
Task_token* readsyms_blocker_;
Task_token* this_blocker_;
Task_token* next_blocker_;
};
} // End namespace gold.
#endif // !defined(GOLD_ARCHIVE_H)