1 // gold.cc -- main linker functions
3 // Copyright 2006, 2007 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"
32 #include "workqueue.h"
33 #include "dirsearch.h"
45 const char* program_name;
48 gold_exit(bool status)
50 if (!status && parameters != NULL)
51 unlink_if_ordinary(parameters->output_file_name());
52 exit(status ? EXIT_SUCCESS : EXIT_FAILURE);
58 // We are out of memory, so try hard to print a reasonable message.
59 // Note that we don't try to translate this message, since the
60 // translation process itself will require memory.
61 write(2, program_name, strlen(program_name));
62 const char* const s = ": out of memory\n";
63 write(2, s, strlen(s));
67 // Handle an unreachable case.
70 do_gold_unreachable(const char* filename, int lineno, const char* function)
72 fprintf(stderr, _("%s: internal error in %s, at %s:%d\n"),
73 program_name, function, filename, lineno);
77 // This class arranges to run the functions done in the middle of the
78 // link. It is just a closure.
80 class Middle_runner : public Task_function_runner
83 Middle_runner(const General_options& options,
84 const Input_objects* input_objects,
87 : options_(options), input_objects_(input_objects), symtab_(symtab),
95 const General_options& options_;
96 const Input_objects* input_objects_;
97 Symbol_table* symtab_;
102 Middle_runner::run(Workqueue* workqueue)
104 queue_middle_tasks(this->options_, this->input_objects_, this->symtab_,
105 this->layout_, workqueue);
108 // Queue up the initial set of tasks for this link job.
111 queue_initial_tasks(const General_options& options,
112 const Dirsearch& search_path,
113 const Command_line& cmdline,
114 Workqueue* workqueue, Input_objects* input_objects,
115 Symbol_table* symtab, Layout* layout)
117 if (cmdline.begin() == cmdline.end())
118 gold_fatal(_("no input files"));
120 int thread_count = options.thread_count_initial();
121 if (thread_count == 0)
122 thread_count = cmdline.number_of_input_files();
123 workqueue->set_thread_count(thread_count);
125 // Read the input files. We have to add the symbols to the symbol
126 // table in order. We do this by creating a separate blocker for
127 // each input file. We associate the blocker with the following
128 // input file, to give us a convenient place to delete it.
129 Task_token* this_blocker = NULL;
130 for (Command_line::const_iterator p = cmdline.begin();
134 Task_token* next_blocker = new Task_token();
135 next_blocker->add_blocker();
136 workqueue->queue(new Read_symbols(options, input_objects, symtab, layout,
137 search_path, &*p, NULL, this_blocker,
139 this_blocker = next_blocker;
142 workqueue->queue(new Task_function(new Middle_runner(options,
149 // Queue up the middle set of tasks. These are the tasks which run
150 // after all the input objects have been found and all the symbols
151 // have been read, but before we lay out the output file.
154 queue_middle_tasks(const General_options& options,
155 const Input_objects* input_objects,
156 Symbol_table* symtab,
158 Workqueue* workqueue)
160 if (input_objects->number_of_input_objects() == 0)
162 // We had some input files, but we weren't able to open any of
164 gold_fatal(_("no input files"));
167 int thread_count = options.thread_count_middle();
168 if (thread_count == 0)
169 thread_count = input_objects->number_of_input_objects();
170 workqueue->set_thread_count(thread_count);
172 // Now we have seen all the input files.
173 const bool doing_static_link = (!input_objects->any_dynamic()
174 && !parameters->output_is_shared());
175 set_parameters_doing_static_link(doing_static_link);
176 if (!doing_static_link && options.is_static())
178 // We print out just the first .so we see; there may be others.
179 gold_error(_("cannot mix -static with dynamic object %s"),
180 (*input_objects->dynobj_begin())->name().c_str());
183 // For each dynamic object, record whether we've seen all the
184 // dynamic objects that it depends upon.
185 input_objects->check_dynamic_dependencies();
187 // See if any of the input definitions violate the One Definition Rule.
188 // TODO: if this is too slow, do this as a task, rather than inline.
189 symtab->detect_odr_violations();
191 // Define some sections and symbols needed for a dynamic link. This
192 // handles some cases we want to see before we read the relocs.
193 layout->create_initial_dynamic_sections(input_objects, symtab);
195 // Predefine standard symbols. This should be fast, so we don't
196 // bother to create a task for it.
197 define_standard_symbols(symtab, layout, input_objects->target());
199 // Define __start and __stop symbols for output sections where
201 layout->define_section_symbols(symtab, input_objects->target());
203 // Read the relocations of the input files. We do this to find
204 // which symbols are used by relocations which require a GOT and/or
205 // a PLT entry, or a COPY reloc. When we implement garbage
206 // collection we will do it here by reading the relocations in a
207 // breadth first search by references.
209 // We could also read the relocations during the first pass, and
210 // mark symbols at that time. That is how the old GNU linker works.
211 // Doing that is more complex, since we may later decide to discard
212 // some of the sections, and thus change our minds about the types
213 // of references made to the symbols.
214 Task_token* blocker = new Task_token();
215 Task_token* symtab_lock = new Task_token();
216 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
217 p != input_objects->relobj_end();
220 // We can read and process the relocations in any order. But we
221 // only want one task to write to the symbol table at a time.
222 // So we queue up a task for each object to read the
223 // relocations. That task will in turn queue a task to wait
224 // until it can write to the symbol table.
225 blocker->add_blocker();
226 workqueue->queue(new Read_relocs(options, symtab, layout, *p,
227 symtab_lock, blocker));
230 // Allocate common symbols. This requires write access to the
231 // symbol table, but is independent of the relocation processing.
232 blocker->add_blocker();
233 workqueue->queue(new Allocate_commons_task(options, symtab, layout,
234 symtab_lock, blocker));
236 // When all those tasks are complete, we can start laying out the
238 workqueue->queue(new Task_function(new Layout_task_runner(options,
245 // Queue up the final set of tasks. This is called at the end of
249 queue_final_tasks(const General_options& options,
250 const Input_objects* input_objects,
251 const Symbol_table* symtab,
252 const Layout* layout,
253 Workqueue* workqueue,
256 int thread_count = options.thread_count_final();
257 if (thread_count == 0)
258 thread_count = input_objects->number_of_input_objects();
259 workqueue->set_thread_count(thread_count);
261 // Use a blocker to wait until all the input sections have been
263 Task_token* input_sections_blocker = new Task_token();
265 // Use a blocker to block any objects which have to wait for the
266 // output sections to complete before they can apply relocations.
267 Task_token* output_sections_blocker = new Task_token();
269 // Use a blocker to block the final cleanup task.
270 Task_token* final_blocker = new Task_token();
272 // Queue a task for each input object to relocate the sections and
273 // write out the local symbols.
274 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
275 p != input_objects->relobj_end();
278 input_sections_blocker->add_blocker();
279 final_blocker->add_blocker();
280 workqueue->queue(new Relocate_task(options, symtab, layout, *p, of,
281 input_sections_blocker,
282 output_sections_blocker,
286 // Queue a task to write out the symbol table.
287 final_blocker->add_blocker();
288 workqueue->queue(new Write_symbols_task(symtab,
295 // Queue a task to write out the output sections.
296 output_sections_blocker->add_blocker();
297 final_blocker->add_blocker();
298 workqueue->queue(new Write_sections_task(layout, of, output_sections_blocker,
301 // Queue a task to write out everything else.
302 final_blocker->add_blocker();
303 workqueue->queue(new Write_data_task(layout, symtab, of, final_blocker));
305 // Queue a task to write out the output sections which depend on
307 final_blocker->add_blocker();
308 workqueue->queue(new Write_after_input_sections_task(layout, of,
309 input_sections_blocker,
312 // Queue a task to close the output file. This will be blocked by
314 workqueue->queue(new Task_function(new Close_task_runner(of),
318 } // End namespace gold.