binutils-gdb/gold/readsyms.cc

947 lines
26 KiB
C++

// readsyms.cc -- read input file symbols for gold
// Copyright (C) 2006-2020 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.
#include "gold.h"
#include <cstring>
#include "elfcpp.h"
#include "options.h"
#include "dirsearch.h"
#include "symtab.h"
#include "object.h"
#include "archive.h"
#include "script.h"
#include "readsyms.h"
#include "plugin.h"
#include "layout.h"
#include "incremental.h"
namespace gold
{
// If we fail to open the object, then we won't create an Add_symbols
// task. However, we still need to unblock the token, or else the
// link won't proceed to generate more error messages. We can only
// unblock tokens when the workqueue lock is held, so we need a dummy
// task to do that. The dummy task has to maintain the right sequence
// of blocks, so we need both this_blocker and next_blocker.
class Unblock_token : public Task
{
public:
Unblock_token(Task_token* this_blocker, Task_token* next_blocker)
: this_blocker_(this_blocker), next_blocker_(next_blocker)
{ }
~Unblock_token()
{
if (this->this_blocker_ != NULL)
delete this->this_blocker_;
}
Task_token*
is_runnable()
{
if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
return this->this_blocker_;
return NULL;
}
void
locks(Task_locker* tl)
{ tl->add(this, this->next_blocker_); }
void
run(Workqueue*)
{ }
std::string
get_name() const
{ return "Unblock_token"; }
private:
Task_token* this_blocker_;
Task_token* next_blocker_;
};
// Class read_symbols.
Read_symbols::~Read_symbols()
{
// The this_blocker_ and next_blocker_ pointers are passed on to the
// Add_symbols task.
}
// If appropriate, issue a warning about skipping an incompatible
// file.
void
Read_symbols::incompatible_warning(const Input_argument* input_argument,
const Input_file* input_file)
{
if (parameters->options().warn_search_mismatch())
gold_warning("skipping incompatible %s while searching for %s",
input_file->filename().c_str(),
input_argument->file().name());
}
// Requeue a Read_symbols task to search for the next object with the
// same name.
void
Read_symbols::requeue(Workqueue* workqueue, Input_objects* input_objects,
Symbol_table* symtab, Layout* layout, Dirsearch* dirpath,
int dirindex, Mapfile* mapfile,
const Input_argument* input_argument,
Input_group* input_group, Task_token* next_blocker)
{
// Bump the directory search index.
++dirindex;
// We don't need to worry about this_blocker, since we already
// reached it. However, we are removing the blocker on next_blocker
// because the calling task is completing. So we need to add a new
// blocker. Since next_blocker may be shared by several tasks, we
// need to increment the count with the workqueue lock held.
workqueue->add_blocker(next_blocker);
workqueue->queue(new Read_symbols(input_objects, symtab, layout, dirpath,
dirindex, mapfile, input_argument,
input_group, NULL, NULL, next_blocker));
}
// Return whether a Read_symbols task is runnable. We can read an
// ordinary input file immediately. For an archive specified using
// -l, we have to wait until the search path is complete.
Task_token*
Read_symbols::is_runnable()
{
if (this->input_argument_->is_file()
&& this->input_argument_->file().may_need_search()
&& this->dirpath_->token()->is_blocked())
return this->dirpath_->token();
return NULL;
}
// Return a Task_locker for a Read_symbols task. We don't need any
// locks here.
void
Read_symbols::locks(Task_locker* tl)
{
if (this->member_ != NULL)
tl->add(this, this->next_blocker_);
}
// Run a Read_symbols task.
void
Read_symbols::run(Workqueue* workqueue)
{
// If we didn't queue a new task, then we need to explicitly unblock
// the token. If the object is a member of a lib group, however,
// the token was already added to the list of locks for the task,
// and it will be unblocked automatically at the end of the task.
if (!this->do_read_symbols(workqueue) && this->member_ == NULL)
workqueue->queue_soon(new Unblock_token(this->this_blocker_,
this->next_blocker_));
}
// Handle a whole lib group. Other than collecting statistics, this just
// mimics what we do for regular object files in the command line.
bool
Read_symbols::do_whole_lib_group(Workqueue* workqueue)
{
const Input_file_lib* lib_group = this->input_argument_->lib();
++Lib_group::total_lib_groups;
Task_token* this_blocker = this->this_blocker_;
for (Input_file_lib::const_iterator i = lib_group->begin();
i != lib_group->end();
++i)
{
++Lib_group::total_members;
++Lib_group::total_members_loaded;
const Input_argument* arg = &*i;
Task_token* next_blocker;
if (i != lib_group->end() - 1)
{
next_blocker = new Task_token(true);
next_blocker->add_blocker();
}
else
next_blocker = this->next_blocker_;
workqueue->queue_soon(new Read_symbols(this->input_objects_,
this->symtab_, this->layout_,
this->dirpath_, this->dirindex_,
this->mapfile_, arg, NULL,
NULL, this_blocker, next_blocker));
this_blocker = next_blocker;
}
return true;
}
// Handle a lib group. We set Read_symbols Tasks as usual, but have them
// just record the symbol data instead of adding the objects. We also start
// a Add_lib_group_symbols Task which runs after we've read all the symbols.
// In that task we process the members in a loop until we are done.
bool
Read_symbols::do_lib_group(Workqueue* workqueue)
{
const Input_file_lib* lib_group = this->input_argument_->lib();
if (lib_group->options().whole_archive())
return this->do_whole_lib_group(workqueue);
Lib_group* lib = new Lib_group(lib_group, this);
Add_lib_group_symbols* add_lib_group_symbols =
new Add_lib_group_symbols(this->symtab_, this->layout_,
this->input_objects_,
lib, this->next_blocker_);
Task_token* next_blocker = new Task_token(true);
int j = 0;
for (Input_file_lib::const_iterator i = lib_group->begin();
i != lib_group->end();
++i, ++j)
{
const Input_argument* arg = &*i;
Archive_member* m = lib->get_member(j);
next_blocker->add_blocker();
// Since this Read_symbols will not create an Add_symbols,
// just pass NULL as this_blocker.
workqueue->queue_soon(new Read_symbols(this->input_objects_,
this->symtab_, this->layout_,
this->dirpath_, this->dirindex_,
this->mapfile_, arg, NULL,
m, NULL, next_blocker));
}
add_lib_group_symbols->set_blocker(next_blocker, this->this_blocker_);
workqueue->queue_soon(add_lib_group_symbols);
return true;
}
// Open the file and read the symbols. Return true if a new task was
// queued, false if that could not happen due to some error.
bool
Read_symbols::do_read_symbols(Workqueue* workqueue)
{
if (this->input_argument_->is_group())
{
gold_assert(this->input_group_ == NULL);
this->do_group(workqueue);
return true;
}
if (this->input_argument_->is_lib())
return this->do_lib_group(workqueue);
Input_file* input_file = new Input_file(&this->input_argument_->file());
if (!input_file->open(*this->dirpath_, this, &this->dirindex_))
return false;
// Read enough of the file to pick up the entire ELF header.
off_t filesize = input_file->file().filesize();
if (filesize == 0)
{
gold_error(_("%s: file is empty"),
input_file->file().filename().c_str());
return false;
}
const unsigned char* ehdr;
int read_size;
bool is_elf = is_elf_object(input_file, 0, &ehdr, &read_size);
if (read_size >= Archive::sarmag)
{
bool is_thin_archive
= memcmp(ehdr, Archive::armagt, Archive::sarmag) == 0;
if (is_thin_archive
|| memcmp(ehdr, Archive::armag, Archive::sarmag) == 0)
{
// This is an archive.
Archive* arch = new Archive(this->input_argument_->file().name(),
input_file, is_thin_archive,
this->dirpath_, this);
arch->setup();
// Unlock the archive so it can be used in the next task.
arch->unlock(this);
workqueue->queue_next(new Add_archive_symbols(this->symtab_,
this->layout_,
this->input_objects_,
this->dirpath_,
this->dirindex_,
this->mapfile_,
this->input_argument_,
arch,
this->input_group_,
this->this_blocker_,
this->next_blocker_));
return true;
}
}
Object* elf_obj = NULL;
bool unconfigured;
bool* punconfigured = NULL;
if (is_elf)
{
// This is an ELF object.
unconfigured = false;
punconfigured = (input_file->will_search_for()
? &unconfigured
: NULL);
elf_obj = make_elf_object(input_file->filename(),
input_file, 0, ehdr, read_size,
punconfigured);
}
if (parameters->options().has_plugins())
{
Pluginobj* obj = parameters->options().plugins()->claim_file(input_file,
0, filesize,
elf_obj);
if (obj != NULL)
{
// Delete the elf_obj, this file has been claimed.
if (elf_obj != NULL)
delete elf_obj;
// The input file was claimed by a plugin, and its symbols
// have been provided by the plugin.
// We are done with the file at this point, so unlock it.
obj->unlock(this);
if (this->member_ != NULL)
{
this->member_->sd_ = NULL;
this->member_->obj_ = obj;
return true;
}
workqueue->queue_next(new Add_symbols(this->input_objects_,
this->symtab_,
this->layout_,
this->dirpath_,
this->dirindex_,
this->mapfile_,
this->input_argument_,
obj,
NULL,
NULL,
this->this_blocker_,
this->next_blocker_));
return true;
}
}
if (is_elf)
{
// This is an ELF object.
if (elf_obj == NULL)
{
if (unconfigured)
{
Read_symbols::incompatible_warning(this->input_argument_,
input_file);
input_file->file().release();
input_file->file().unlock(this);
delete input_file;
++this->dirindex_;
return this->do_read_symbols(workqueue);
}
return false;
}
Read_symbols_data* sd = new Read_symbols_data;
elf_obj->read_symbols(sd);
// Opening the file locked it, so now we need to unlock it. We
// need to unlock it before queuing the Add_symbols task,
// because the workqueue doesn't know about our lock on the
// file. If we queue the Add_symbols task first, it will be
// stuck on the end of the file lock, but since the workqueue
// doesn't know about that lock, it will never release the
// Add_symbols task.
input_file->file().unlock(this);
if (this->member_ != NULL)
{
this->member_->sd_ = sd;
this->member_->obj_ = elf_obj;
this->member_->arg_serial_ =
this->input_argument_->file().arg_serial();
return true;
}
// We use queue_next because everything is cached for this
// task to run right away if possible.
workqueue->queue_next(new Add_symbols(this->input_objects_,
this->symtab_, this->layout_,
this->dirpath_,
this->dirindex_,
this->mapfile_,
this->input_argument_,
elf_obj,
NULL,
sd,
this->this_blocker_,
this->next_blocker_));
return true;
}
// Queue up a task to try to parse this file as a script. We use a
// separate task so that the script will be read in order with other
// objects named on the command line. Also so that we don't try to
// read multiple scripts simultaneously, which could lead to
// unpredictable changes to the General_options structure.
workqueue->queue_soon(new Read_script(this->symtab_,
this->layout_,
this->dirpath_,
this->dirindex_,
this->input_objects_,
this->mapfile_,
this->input_group_,
this->input_argument_,
input_file,
this->this_blocker_,
this->next_blocker_));
return true;
}
// Handle a group. We need to walk through the arguments over and
// over until we don't see any new undefined symbols. We do this by
// setting off Read_symbols Tasks as usual, but recording the archive
// entries instead of deleting them. We also start a Finish_group
// Task which runs after we've read all the symbols. In that task we
// process the archives in a loop until we are done.
void
Read_symbols::do_group(Workqueue* workqueue)
{
Input_group* input_group = new Input_group();
const Input_file_group* group = this->input_argument_->group();
Task_token* this_blocker = this->this_blocker_;
Finish_group* finish_group = new Finish_group(this->input_objects_,
this->symtab_,
this->layout_,
this->mapfile_,
input_group,
this->next_blocker_);
Task_token* next_blocker = new Task_token(true);
next_blocker->add_blocker();
workqueue->queue_soon(new Start_group(this->symtab_, finish_group,
this_blocker, next_blocker));
this_blocker = next_blocker;
for (Input_file_group::const_iterator p = group->begin();
p != group->end();
++p)
{
const Input_argument* arg = &*p;
gold_assert(arg->is_file());
next_blocker = new Task_token(true);
next_blocker->add_blocker();
workqueue->queue_soon(new Read_symbols(this->input_objects_,
this->symtab_, this->layout_,
this->dirpath_, this->dirindex_,
this->mapfile_, arg, input_group,
NULL, this_blocker, next_blocker));
this_blocker = next_blocker;
}
finish_group->set_blocker(this_blocker);
workqueue->queue_soon(finish_group);
}
// Return a debugging name for a Read_symbols task.
std::string
Read_symbols::get_name() const
{
if (this->input_argument_->is_group())
{
std::string ret("Read_symbols group (");
bool add_space = false;
const Input_file_group* group = this->input_argument_->group();
for (Input_file_group::const_iterator p = group->begin();
p != group->end();
++p)
{
if (add_space)
ret += ' ';
ret += p->file().name();
add_space = true;
}
return ret + ')';
}
else if (this->input_argument_->is_lib())
{
std::string ret("Read_symbols lib (");
bool add_space = false;
const Input_file_lib* lib = this->input_argument_->lib();
for (Input_file_lib::const_iterator p = lib->begin();
p != lib->end();
++p)
{
if (add_space)
ret += ' ';
ret += p->file().name();
add_space = true;
}
return ret + ')';
}
else
{
std::string ret("Read_symbols ");
if (this->input_argument_->file().is_lib())
ret += "-l";
else if (this->input_argument_->file().is_searched_file())
ret += "-l:";
ret += this->input_argument_->file().name();
return ret;
}
}
// Class Add_symbols.
Add_symbols::~Add_symbols()
{
if (this->this_blocker_ != NULL)
delete this->this_blocker_;
// next_blocker_ is deleted by the task associated with the next
// input file.
}
// We are blocked by this_blocker_. We block next_blocker_. We also
// lock the file.
Task_token*
Add_symbols::is_runnable()
{
if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
return this->this_blocker_;
if (this->object_->is_locked())
return this->object_->token();
return NULL;
}
void
Add_symbols::locks(Task_locker* tl)
{
tl->add(this, this->next_blocker_);
Task_token* token = this->object_->token();
if (token != NULL)
tl->add(this, token);
}
// Add the symbols in the object to the symbol table.
void
Add_symbols::run(Workqueue*)
{
Pluginobj* pluginobj = this->object_->pluginobj();
if (pluginobj != NULL)
{
this->object_->add_symbols(this->symtab_, this->sd_, this->layout_);
return;
}
if (!this->input_objects_->add_object(this->object_))
{
this->object_->discard_decompressed_sections();
gold_assert(this->sd_ != NULL);
delete this->sd_;
this->sd_ = NULL;
this->object_->release();
delete this->object_;
}
else
{
Incremental_inputs* incremental_inputs =
this->layout_->incremental_inputs();
if (incremental_inputs != NULL)
{
if (this->library_ != NULL && !this->library_->is_reported())
{
Incremental_binary* ibase = this->layout_->incremental_base();
gold_assert(ibase != NULL);
unsigned int lib_serial = this->library_->arg_serial();
unsigned int lib_index = this->library_->input_file_index();
Script_info* lib_script_info = ibase->get_script_info(lib_index);
incremental_inputs->report_archive_begin(this->library_,
lib_serial,
lib_script_info);
}
unsigned int arg_serial = this->input_argument_->file().arg_serial();
Script_info* script_info = this->input_argument_->script_info();
incremental_inputs->report_object(this->object_, arg_serial,
this->library_, script_info);
}
this->object_->layout(this->symtab_, this->layout_, this->sd_);
this->object_->add_symbols(this->symtab_, this->sd_, this->layout_);
this->object_->discard_decompressed_sections();
delete this->sd_;
this->sd_ = NULL;
this->object_->release();
}
}
// Class Read_member.
Read_member::~Read_member()
{
if (this->this_blocker_ != NULL)
delete this->this_blocker_;
// next_blocker_ is deleted by the task associated with the next
// input file.
}
// Return whether a Read_member task is runnable.
Task_token*
Read_member::is_runnable()
{
if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
return this->this_blocker_;
return NULL;
}
void
Read_member::locks(Task_locker* tl)
{
tl->add(this, this->next_blocker_);
}
// Run a Read_member task.
void
Read_member::run(Workqueue*)
{
// This task doesn't need to do anything for now. The Read_symbols task
// that is queued for the archive library will cause the archive to be
// processed from scratch.
}
// Class Check_script.
Check_script::~Check_script()
{
if (this->this_blocker_ != NULL)
delete this->this_blocker_;
// next_blocker_ is deleted by the task associated with the next
// input file.
}
// Return whether a Check_script task is runnable.
Task_token*
Check_script::is_runnable()
{
if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
return this->this_blocker_;
return NULL;
}
void
Check_script::locks(Task_locker* tl)
{
tl->add(this, this->next_blocker_);
}
// Run a Check_script task.
void
Check_script::run(Workqueue*)
{
Incremental_inputs* incremental_inputs = this->layout_->incremental_inputs();
gold_assert(incremental_inputs != NULL);
unsigned int arg_serial = this->input_reader_->arg_serial();
Script_info* script_info =
this->ibase_->get_script_info(this->input_file_index_);
Timespec mtime = this->input_reader_->get_mtime();
incremental_inputs->report_script(script_info, arg_serial, mtime);
}
// Class Check_library.
Check_library::~Check_library()
{
if (this->this_blocker_ != NULL)
delete this->this_blocker_;
// next_blocker_ is deleted by the task associated with the next
// input file.
}
// Return whether a Check_library task is runnable.
Task_token*
Check_library::is_runnable()
{
if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
return this->this_blocker_;
return NULL;
}
void
Check_library::locks(Task_locker* tl)
{
tl->add(this, this->next_blocker_);
}
// Run a Check_library task.
void
Check_library::run(Workqueue*)
{
Incremental_inputs* incremental_inputs = this->layout_->incremental_inputs();
gold_assert(incremental_inputs != NULL);
Incremental_library* lib = this->ibase_->get_library(this->input_file_index_);
gold_assert(lib != NULL);
lib->copy_unused_symbols();
// FIXME: Check that unused symbols remain unused.
if (!lib->is_reported())
{
unsigned int lib_serial = lib->arg_serial();
unsigned int lib_index = lib->input_file_index();
Script_info* script_info = this->ibase_->get_script_info(lib_index);
incremental_inputs->report_archive_begin(lib, lib_serial, script_info);
}
incremental_inputs->report_archive_end(lib);
}
// Class Input_group.
// When we delete an Input_group we can delete the archive
// information.
Input_group::~Input_group()
{
for (Input_group::const_iterator p = this->begin();
p != this->end();
++p)
delete *p;
}
// Class Start_group.
Start_group::~Start_group()
{
if (this->this_blocker_ != NULL)
delete this->this_blocker_;
// next_blocker_ is deleted by the task associated with the first
// file in the group.
}
// We need to wait for THIS_BLOCKER_ and unblock NEXT_BLOCKER_.
Task_token*
Start_group::is_runnable()
{
if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
return this->this_blocker_;
return NULL;
}
void
Start_group::locks(Task_locker* tl)
{
tl->add(this, this->next_blocker_);
}
// Store the number of undefined symbols we see now.
void
Start_group::run(Workqueue*)
{
this->finish_group_->set_saw_undefined(this->symtab_->saw_undefined());
}
// Class Finish_group.
Finish_group::~Finish_group()
{
if (this->this_blocker_ != NULL)
delete this->this_blocker_;
// next_blocker_ is deleted by the task associated with the next
// input file following the group.
}
// We need to wait for THIS_BLOCKER_ and unblock NEXT_BLOCKER_.
Task_token*
Finish_group::is_runnable()
{
if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
return this->this_blocker_;
return NULL;
}
void
Finish_group::locks(Task_locker* tl)
{
tl->add(this, this->next_blocker_);
}
// Loop over the archives until there are no new undefined symbols.
void
Finish_group::run(Workqueue*)
{
size_t saw_undefined = this->saw_undefined_;
while (saw_undefined != this->symtab_->saw_undefined())
{
saw_undefined = this->symtab_->saw_undefined();
for (Input_group::const_iterator p = this->input_group_->begin();
p != this->input_group_->end();
++p)
{
Task_lock_obj<Archive> tl(this, *p);
(*p)->add_symbols(this->symtab_, this->layout_,
this->input_objects_, this->mapfile_);
}
}
// Now that we're done with the archives, record the incremental
// layout information.
for (Input_group::const_iterator p = this->input_group_->begin();
p != this->input_group_->end();
++p)
{
// For an incremental link, finish recording the layout information.
Incremental_inputs* incremental_inputs =
this->layout_->incremental_inputs();
if (incremental_inputs != NULL)
incremental_inputs->report_archive_end(*p);
}
if (parameters->options().has_plugins())
parameters->options().plugins()->save_input_group(this->input_group_);
else
delete this->input_group_;
}
// Class Read_script
Read_script::~Read_script()
{
if (this->this_blocker_ != NULL)
delete this->this_blocker_;
// next_blocker_ is deleted by the task associated with the next
// input file.
}
// We are blocked by this_blocker_.
Task_token*
Read_script::is_runnable()
{
if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
return this->this_blocker_;
return NULL;
}
// We don't unlock next_blocker_ here. If the script names any input
// files, then the last file will be responsible for unlocking it.
void
Read_script::locks(Task_locker*)
{
}
// Read the script, if it is a script.
void
Read_script::run(Workqueue* workqueue)
{
bool used_next_blocker;
if (!read_input_script(workqueue, this->symtab_, this->layout_,
this->dirpath_, this->dirindex_, this->input_objects_,
this->mapfile_, this->input_group_,
this->input_argument_, this->input_file_,
this->next_blocker_, &used_next_blocker))
{
// Here we have to handle any other input file types we need.
gold_error(_("%s: not an object or archive"),
this->input_file_->file().filename().c_str());
}
if (!used_next_blocker)
{
// Queue up a task to unlock next_blocker. We can't just unlock
// it here, as we don't hold the workqueue lock.
workqueue->queue_soon(new Unblock_token(NULL, this->next_blocker_));
}
}
// Return a debugging name for a Read_script task.
std::string
Read_script::get_name() const
{
std::string ret("Read_script ");
if (this->input_argument_->file().is_lib())
ret += "-l";
else if (this->input_argument_->file().is_searched_file())
ret += "-l:";
ret += this->input_argument_->file().name();
return ret;
}
} // End namespace gold.