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.
31 #include "workqueue.h"
32 #include "dirsearch.h"
44 const char* program_name;
47 gold_exit(bool status)
49 exit(status ? EXIT_SUCCESS : EXIT_FAILURE);
53 gold_fatal(const char* msg, bool perrno)
55 fprintf(stderr, "%s: ", program_name);
59 fprintf(stderr, "%s\n", msg);
66 // We are out of memory, so try hard to print a reasonable message.
67 // Note that we don't try to translate this message, since the
68 // translation process itself will require memory.
69 write(2, program_name, strlen(program_name));
70 const char* const s = ": out of memory\n";
71 write(2, s, strlen(s));
75 // Handle an unreachable case.
78 do_gold_unreachable(const char* filename, int lineno, const char* function)
80 fprintf(stderr, _("%s: internal error in %s, at %s:%d\n"),
81 program_name, function, filename, lineno);
85 // This class arranges to run the functions done in the middle of the
86 // link. It is just a closure.
88 class Middle_runner : public Task_function_runner
91 Middle_runner(const General_options& options,
92 const Input_objects* input_objects,
95 : options_(options), input_objects_(input_objects), symtab_(symtab),
103 const General_options& options_;
104 const Input_objects* input_objects_;
105 Symbol_table* symtab_;
110 Middle_runner::run(Workqueue* workqueue)
112 queue_middle_tasks(this->options_, this->input_objects_, this->symtab_,
113 this->layout_, workqueue);
116 // Queue up the initial set of tasks for this link job.
119 queue_initial_tasks(const General_options& options,
120 const Dirsearch& search_path,
121 const Command_line& cmdline,
122 Workqueue* workqueue, Input_objects* input_objects,
123 Symbol_table* symtab, Layout* layout)
125 if (cmdline.begin() == cmdline.end())
126 gold_fatal(_("no input files"), false);
128 // Read the input files. We have to add the symbols to the symbol
129 // table in order. We do this by creating a separate blocker for
130 // each input file. We associate the blocker with the following
131 // input file, to give us a convenient place to delete it.
132 Task_token* this_blocker = NULL;
133 for (Command_line::const_iterator p = cmdline.begin();
137 Task_token* next_blocker = new Task_token();
138 next_blocker->add_blocker();
139 workqueue->queue(new Read_symbols(options, input_objects, symtab, layout,
140 search_path, &*p, NULL, this_blocker,
142 this_blocker = next_blocker;
145 workqueue->queue(new Task_function(new Middle_runner(options,
152 // Queue up the middle set of tasks. These are the tasks which run
153 // after all the input objects have been found and all the symbols
154 // have been read, but before we lay out the output file.
157 queue_middle_tasks(const General_options& options,
158 const Input_objects* input_objects,
159 Symbol_table* symtab,
161 Workqueue* workqueue)
163 // Now we have seen all the input files.
164 const bool doing_static_link = !input_objects->any_dynamic();
165 set_parameters_doing_static_link(doing_static_link);
166 if (!doing_static_link && options.is_static())
168 // We print out just the first .so we see; there may be others.
169 fprintf(stderr, _("%s: cannot mix -static with dynamic object %s\n"),
170 program_name, (*input_objects->dynobj_begin())->name().c_str());
174 // Define some sections and symbols needed for a dynamic link. This
175 // handles some cases we want to see before we read the relocs.
176 layout->create_initial_dynamic_sections(input_objects, symtab);
178 // Predefine standard symbols. This should be fast, so we don't
179 // bother to create a task for it.
180 define_standard_symbols(symtab, layout, input_objects->target());
182 // Define __start and __stop symbols for output sections where
184 layout->define_section_symbols(symtab, input_objects->target());
186 // Read the relocations of the input files. We do this to find
187 // which symbols are used by relocations which require a GOT and/or
188 // a PLT entry, or a COPY reloc. When we implement garbage
189 // collection we will do it here by reading the relocations in a
190 // breadth first search by references.
192 // We could also read the relocations during the first pass, and
193 // mark symbols at that time. That is how the old GNU linker works.
194 // Doing that is more complex, since we may later decide to discard
195 // some of the sections, and thus change our minds about the types
196 // of references made to the symbols.
197 Task_token* blocker = new Task_token();
198 Task_token* symtab_lock = new Task_token();
199 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
200 p != input_objects->relobj_end();
203 // We can read and process the relocations in any order. But we
204 // only want one task to write to the symbol table at a time.
205 // So we queue up a task for each object to read the
206 // relocations. That task will in turn queue a task to wait
207 // until it can write to the symbol table.
208 blocker->add_blocker();
209 workqueue->queue(new Read_relocs(options, symtab, layout, *p,
210 symtab_lock, blocker));
213 // Allocate common symbols. This requires write access to the
214 // symbol table, but is independent of the relocation processing.
215 blocker->add_blocker();
216 workqueue->queue(new Allocate_commons_task(options, symtab, layout,
217 symtab_lock, blocker));
219 // When all those tasks are complete, we can start laying out the
221 workqueue->queue(new Task_function(new Layout_task_runner(options,
228 // Queue up the final set of tasks. This is called at the end of
232 queue_final_tasks(const General_options& options,
233 const Input_objects* input_objects,
234 const Symbol_table* symtab,
235 const Layout* layout,
236 Workqueue* workqueue,
239 // Use a blocker to block the final cleanup task.
240 Task_token* final_blocker = new Task_token();
242 // Queue a task for each input object to relocate the sections and
243 // write out the local symbols.
244 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
245 p != input_objects->relobj_end();
248 final_blocker->add_blocker();
249 workqueue->queue(new Relocate_task(options, symtab, layout, *p, of,
253 // Queue a task to write out the symbol table.
254 final_blocker->add_blocker();
255 workqueue->queue(new Write_symbols_task(symtab,
256 input_objects->target(),
262 // Queue a task to write out everything else.
263 final_blocker->add_blocker();
264 workqueue->queue(new Write_data_task(layout, symtab, of, final_blocker));
266 // Queue a task to close the output file. This will be blocked by
268 workqueue->queue(new Task_function(new Close_task_runner(of),
272 } // End namespace gold.