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.