1 // gold.cc -- main linker functions
3 // Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
29 #include "libiberty.h"
33 #include "workqueue.h"
34 #include "dirsearch.h"
46 const char* program_name
;
49 gold_exit(bool status
)
51 if (!status
&& parameters
!= NULL
&& parameters
->options_valid())
52 unlink_if_ordinary(parameters
->output_file_name());
53 exit(status
? EXIT_SUCCESS
: EXIT_FAILURE
);
59 // We are out of memory, so try hard to print a reasonable message.
60 // Note that we don't try to translate this message, since the
61 // translation process itself will require memory.
62 write(2, program_name
, strlen(program_name
));
63 const char* const s
= ": out of memory\n";
64 write(2, s
, strlen(s
));
68 // Handle an unreachable case.
71 do_gold_unreachable(const char* filename
, int lineno
, const char* function
)
73 fprintf(stderr
, _("%s: internal error in %s, at %s:%d\n"),
74 program_name
, function
, filename
, lineno
);
78 // This class arranges to run the functions done in the middle of the
79 // link. It is just a closure.
81 class Middle_runner
: public Task_function_runner
84 Middle_runner(const General_options
& options
,
85 const Input_objects
* input_objects
,
88 : options_(options
), input_objects_(input_objects
), symtab_(symtab
),
93 run(Workqueue
*, const Task
*);
96 const General_options
& options_
;
97 const Input_objects
* input_objects_
;
98 Symbol_table
* symtab_
;
103 Middle_runner::run(Workqueue
* workqueue
, const Task
* task
)
105 queue_middle_tasks(this->options_
, task
, this->input_objects_
, this->symtab_
,
106 this->layout_
, workqueue
);
109 // Queue up the initial set of tasks for this link job.
112 queue_initial_tasks(const General_options
& options
,
113 Dirsearch
& search_path
,
114 const Command_line
& cmdline
,
115 Workqueue
* workqueue
, Input_objects
* input_objects
,
116 Symbol_table
* symtab
, Layout
* layout
)
118 if (cmdline
.begin() == cmdline
.end())
119 gold_fatal(_("no input files"));
121 int thread_count
= options
.thread_count_initial();
122 if (thread_count
== 0)
123 thread_count
= cmdline
.number_of_input_files();
124 workqueue
->set_thread_count(thread_count
);
126 // Read the input files. We have to add the symbols to the symbol
127 // table in order. We do this by creating a separate blocker for
128 // each input file. We associate the blocker with the following
129 // input file, to give us a convenient place to delete it.
130 Task_token
* this_blocker
= NULL
;
131 for (Command_line::const_iterator p
= cmdline
.begin();
135 Task_token
* next_blocker
= new Task_token(true);
136 next_blocker
->add_blocker();
137 workqueue
->queue(new Read_symbols(options
, input_objects
, symtab
, layout
,
138 &search_path
, &*p
, NULL
, this_blocker
,
140 this_blocker
= next_blocker
;
143 workqueue
->queue(new Task_function(new Middle_runner(options
,
148 "Task_function Middle_runner"));
151 // Queue up the middle set of tasks. These are the tasks which run
152 // after all the input objects have been found and all the symbols
153 // have been read, but before we lay out the output file.
156 queue_middle_tasks(const General_options
& options
,
158 const Input_objects
* input_objects
,
159 Symbol_table
* symtab
,
161 Workqueue
* workqueue
)
163 if (input_objects
->number_of_input_objects() == 0)
165 // We had some input files, but we weren't able to open any of
167 gold_fatal(_("no input files"));
170 int thread_count
= options
.thread_count_middle();
171 if (thread_count
== 0)
172 thread_count
= input_objects
->number_of_input_objects();
173 workqueue
->set_thread_count(thread_count
);
175 // Now we have seen all the input files.
176 const bool doing_static_link
= (!input_objects
->any_dynamic()
177 && !parameters
->output_is_shared());
178 set_parameters_doing_static_link(doing_static_link
);
179 if (!doing_static_link
&& options
.is_static())
181 // We print out just the first .so we see; there may be others.
182 gold_error(_("cannot mix -static with dynamic object %s"),
183 (*input_objects
->dynobj_begin())->name().c_str());
186 if (is_debugging_enabled(DEBUG_SCRIPT
))
187 layout
->script_options()->print(stderr
);
189 // For each dynamic object, record whether we've seen all the
190 // dynamic objects that it depends upon.
191 input_objects
->check_dynamic_dependencies();
193 // See if any of the input definitions violate the One Definition Rule.
194 // TODO: if this is too slow, do this as a task, rather than inline.
195 symtab
->detect_odr_violations(task
, options
.output_file_name());
197 // Define some sections and symbols needed for a dynamic link. This
198 // handles some cases we want to see before we read the relocs.
199 layout
->create_initial_dynamic_sections(input_objects
, symtab
);
201 // Predefine standard symbols. This should be fast, so we don't
202 // bother to create a task for it.
203 define_standard_symbols(symtab
, layout
, input_objects
->target());
205 // Define __start and __stop symbols for output sections where
207 layout
->define_section_symbols(symtab
, input_objects
->target());
209 // Define symbols from any linker scripts.
210 layout
->define_script_symbols(symtab
, input_objects
->target());
212 // Read the relocations of the input files. We do this to find
213 // which symbols are used by relocations which require a GOT and/or
214 // a PLT entry, or a COPY reloc. When we implement garbage
215 // collection we will do it here by reading the relocations in a
216 // breadth first search by references.
218 // We could also read the relocations during the first pass, and
219 // mark symbols at that time. That is how the old GNU linker works.
220 // Doing that is more complex, since we may later decide to discard
221 // some of the sections, and thus change our minds about the types
222 // of references made to the symbols.
223 Task_token
* blocker
= new Task_token(true);
224 Task_token
* symtab_lock
= new Task_token(false);
225 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
226 p
!= input_objects
->relobj_end();
229 // We can read and process the relocations in any order. But we
230 // only want one task to write to the symbol table at a time.
231 // So we queue up a task for each object to read the
232 // relocations. That task will in turn queue a task to wait
233 // until it can write to the symbol table.
234 blocker
->add_blocker();
235 workqueue
->queue(new Read_relocs(options
, symtab
, layout
, *p
,
236 symtab_lock
, blocker
));
239 // Allocate common symbols. This requires write access to the
240 // symbol table, but is independent of the relocation processing.
241 blocker
->add_blocker();
242 workqueue
->queue(new Allocate_commons_task(options
, symtab
, layout
,
243 symtab_lock
, blocker
));
245 // When all those tasks are complete, we can start laying out the
247 workqueue
->queue(new Task_function(new Layout_task_runner(options
,
252 "Task_function Layout_task_runner"));
255 // Queue up the final set of tasks. This is called at the end of
259 queue_final_tasks(const General_options
& options
,
260 const Input_objects
* input_objects
,
261 const Symbol_table
* symtab
,
263 Workqueue
* workqueue
,
266 int thread_count
= options
.thread_count_final();
267 if (thread_count
== 0)
268 thread_count
= input_objects
->number_of_input_objects();
269 workqueue
->set_thread_count(thread_count
);
271 bool any_postprocessing_sections
= layout
->any_postprocessing_sections();
273 // Use a blocker to wait until all the input sections have been
275 Task_token
* input_sections_blocker
= NULL
;
276 if (!any_postprocessing_sections
)
277 input_sections_blocker
= new Task_token(true);
279 // Use a blocker to block any objects which have to wait for the
280 // output sections to complete before they can apply relocations.
281 Task_token
* output_sections_blocker
= new Task_token(true);
283 // Use a blocker to block the final cleanup task.
284 Task_token
* final_blocker
= new Task_token(true);
286 // Queue a task to write out the symbol table.
287 if (!options
.strip_all())
289 final_blocker
->add_blocker();
290 workqueue
->queue(new Write_symbols_task(symtab
,
298 // Queue a task to write out the output sections.
299 output_sections_blocker
->add_blocker();
300 final_blocker
->add_blocker();
301 workqueue
->queue(new Write_sections_task(layout
, of
, output_sections_blocker
,
304 // Queue a task to write out everything else.
305 final_blocker
->add_blocker();
306 workqueue
->queue(new Write_data_task(layout
, symtab
, of
, final_blocker
));
308 // Queue a task for each input object to relocate the sections and
309 // write out the local symbols.
310 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
311 p
!= input_objects
->relobj_end();
314 if (input_sections_blocker
!= NULL
)
315 input_sections_blocker
->add_blocker();
316 final_blocker
->add_blocker();
317 workqueue
->queue(new Relocate_task(options
, symtab
, layout
, *p
, of
,
318 input_sections_blocker
,
319 output_sections_blocker
,
323 // Queue a task to write out the output sections which depend on
324 // input sections. If there are any sections which require
325 // postprocessing, then we need to do this last, since it may resize
327 if (!any_postprocessing_sections
)
329 final_blocker
->add_blocker();
330 Task
* t
= new Write_after_input_sections_task(layout
, of
,
331 input_sections_blocker
,
337 Task_token
*new_final_blocker
= new Task_token(true);
338 new_final_blocker
->add_blocker();
339 Task
* t
= new Write_after_input_sections_task(layout
, of
,
343 final_blocker
= new_final_blocker
;
346 // Queue a task to close the output file. This will be blocked by
348 workqueue
->queue(new Task_function(new Close_task_runner(of
),
350 "Task_function Close_task_runner"));
353 } // End namespace gold.