Commit | Line | Data |
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5a6f7e2d | 1 | // gold.cc -- main linker functions |
bae7f79e | 2 | |
e5756efb | 3 | // Copyright 2006, 2007, 2008 Free Software Foundation, Inc. |
6cb15b7f ILT |
4 | // Written by Ian Lance Taylor <iant@google.com>. |
5 | ||
6 | // This file is part of gold. | |
7 | ||
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. | |
12 | ||
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. | |
17 | ||
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. | |
22 | ||
bae7f79e ILT |
23 | #include "gold.h" |
24 | ||
25 | #include <cstdlib> | |
26 | #include <cstdio> | |
27 | #include <cstring> | |
28 | #include <unistd.h> | |
fbfba508 | 29 | #include <algorithm> |
75f2446e | 30 | #include "libiberty.h" |
bae7f79e ILT |
31 | |
32 | #include "options.h" | |
494e05f4 | 33 | #include "debug.h" |
bae7f79e ILT |
34 | #include "workqueue.h" |
35 | #include "dirsearch.h" | |
36 | #include "readsyms.h" | |
14bfc3f5 | 37 | #include "symtab.h" |
ead1e424 | 38 | #include "common.h" |
54dc6425 | 39 | #include "object.h" |
a2fb1b05 | 40 | #include "layout.h" |
61ba1cf9 | 41 | #include "reloc.h" |
ead1e424 | 42 | #include "defstd.h" |
89fc3421 | 43 | #include "plugin.h" |
bae7f79e ILT |
44 | |
45 | namespace gold | |
46 | { | |
47 | ||
48 | const char* program_name; | |
49 | ||
50 | void | |
51 | gold_exit(bool status) | |
52 | { | |
2d684091 | 53 | if (!status && parameters != NULL && parameters->options_valid()) |
8851ecca | 54 | unlink_if_ordinary(parameters->options().output_file_name()); |
bae7f79e ILT |
55 | exit(status ? EXIT_SUCCESS : EXIT_FAILURE); |
56 | } | |
57 | ||
bae7f79e ILT |
58 | void |
59 | gold_nomem() | |
60 | { | |
61 | // We are out of memory, so try hard to print a reasonable message. | |
62 | // Note that we don't try to translate this message, since the | |
63 | // translation process itself will require memory. | |
55ba0940 ILT |
64 | |
65 | // LEN only exists to avoid a pointless warning when write is | |
66 | // declared with warn_use_result, as when compiling with | |
67 | // -D_USE_FORTIFY on GNU/Linux. Casting to void does not appear to | |
68 | // work, at least not with gcc 4.3.0. | |
69 | ||
70 | ssize_t len = write(2, program_name, strlen(program_name)); | |
71 | if (len >= 0) | |
72 | { | |
73 | const char* const s = ": out of memory\n"; | |
74 | len = write(2, s, strlen(s)); | |
75 | } | |
bae7f79e ILT |
76 | gold_exit(false); |
77 | } | |
78 | ||
a3ad94ed ILT |
79 | // Handle an unreachable case. |
80 | ||
bae7f79e | 81 | void |
a3ad94ed | 82 | do_gold_unreachable(const char* filename, int lineno, const char* function) |
bae7f79e | 83 | { |
27b7985a | 84 | fprintf(stderr, _("%s: internal error in %s, at %s:%d\n"), |
a3ad94ed ILT |
85 | program_name, function, filename, lineno); |
86 | gold_exit(false); | |
bae7f79e ILT |
87 | } |
88 | ||
92e059d8 ILT |
89 | // This class arranges to run the functions done in the middle of the |
90 | // link. It is just a closure. | |
bae7f79e | 91 | |
92e059d8 | 92 | class Middle_runner : public Task_function_runner |
bae7f79e | 93 | { |
92e059d8 ILT |
94 | public: |
95 | Middle_runner(const General_options& options, | |
96 | const Input_objects* input_objects, | |
97 | Symbol_table* symtab, | |
7d9e3d98 | 98 | Layout* layout, Mapfile* mapfile) |
92e059d8 | 99 | : options_(options), input_objects_(input_objects), symtab_(symtab), |
7d9e3d98 | 100 | layout_(layout), mapfile_(mapfile) |
92e059d8 ILT |
101 | { } |
102 | ||
103 | void | |
17a1d0a9 | 104 | run(Workqueue*, const Task*); |
92e059d8 ILT |
105 | |
106 | private: | |
107 | const General_options& options_; | |
108 | const Input_objects* input_objects_; | |
109 | Symbol_table* symtab_; | |
110 | Layout* layout_; | |
7d9e3d98 | 111 | Mapfile* mapfile_; |
92e059d8 | 112 | }; |
bae7f79e | 113 | |
92e059d8 | 114 | void |
17a1d0a9 | 115 | Middle_runner::run(Workqueue* workqueue, const Task* task) |
92e059d8 | 116 | { |
17a1d0a9 | 117 | queue_middle_tasks(this->options_, task, this->input_objects_, this->symtab_, |
7d9e3d98 | 118 | this->layout_, workqueue, this->mapfile_); |
92e059d8 | 119 | } |
bae7f79e ILT |
120 | |
121 | // Queue up the initial set of tasks for this link job. | |
122 | ||
123 | void | |
124 | queue_initial_tasks(const General_options& options, | |
17a1d0a9 | 125 | Dirsearch& search_path, |
ead1e424 | 126 | const Command_line& cmdline, |
54dc6425 | 127 | Workqueue* workqueue, Input_objects* input_objects, |
7d9e3d98 | 128 | Symbol_table* symtab, Layout* layout, Mapfile* mapfile) |
bae7f79e | 129 | { |
e5366891 ILT |
130 | if (cmdline.begin() == cmdline.end()) |
131 | gold_fatal(_("no input files")); | |
132 | ||
fe9a4c12 ILT |
133 | int thread_count = options.thread_count_initial(); |
134 | if (thread_count == 0) | |
e5366891 | 135 | thread_count = cmdline.number_of_input_files(); |
fe9a4c12 ILT |
136 | workqueue->set_thread_count(thread_count); |
137 | ||
bae7f79e ILT |
138 | // Read the input files. We have to add the symbols to the symbol |
139 | // table in order. We do this by creating a separate blocker for | |
140 | // each input file. We associate the blocker with the following | |
141 | // input file, to give us a convenient place to delete it. | |
142 | Task_token* this_blocker = NULL; | |
ead1e424 ILT |
143 | for (Command_line::const_iterator p = cmdline.begin(); |
144 | p != cmdline.end(); | |
bae7f79e ILT |
145 | ++p) |
146 | { | |
17a1d0a9 | 147 | Task_token* next_blocker = new Task_token(true); |
bae7f79e | 148 | next_blocker->add_blocker(); |
12e14209 | 149 | workqueue->queue(new Read_symbols(options, input_objects, symtab, layout, |
7d9e3d98 ILT |
150 | &search_path, mapfile, &*p, NULL, |
151 | this_blocker, next_blocker)); | |
bae7f79e ILT |
152 | this_blocker = next_blocker; |
153 | } | |
154 | ||
89fc3421 CC |
155 | if (options.has_plugins()) |
156 | { | |
157 | Task_token* next_blocker = new Task_token(true); | |
158 | next_blocker->add_blocker(); | |
159 | workqueue->queue(new Plugin_hook(options, input_objects, symtab, layout, | |
160 | &search_path, mapfile, this_blocker, | |
161 | next_blocker)); | |
162 | this_blocker = next_blocker; | |
163 | } | |
164 | ||
92e059d8 ILT |
165 | workqueue->queue(new Task_function(new Middle_runner(options, |
166 | input_objects, | |
167 | symtab, | |
7d9e3d98 ILT |
168 | layout, |
169 | mapfile), | |
c7912668 ILT |
170 | this_blocker, |
171 | "Task_function Middle_runner")); | |
bae7f79e ILT |
172 | } |
173 | ||
92e059d8 ILT |
174 | // Queue up the middle set of tasks. These are the tasks which run |
175 | // after all the input objects have been found and all the symbols | |
176 | // have been read, but before we lay out the output file. | |
bae7f79e | 177 | |
92e059d8 ILT |
178 | void |
179 | queue_middle_tasks(const General_options& options, | |
17a1d0a9 | 180 | const Task* task, |
92e059d8 ILT |
181 | const Input_objects* input_objects, |
182 | Symbol_table* symtab, | |
183 | Layout* layout, | |
7d9e3d98 ILT |
184 | Workqueue* workqueue, |
185 | Mapfile* mapfile) | |
61ba1cf9 | 186 | { |
fbfba508 ILT |
187 | // We have to support the case of not seeing any input objects, and |
188 | // generate an empty file. Existing builds depend on being able to | |
189 | // pass an empty archive to the linker and get an empty object file | |
190 | // out. In order to do this we need to use a default target. | |
2c0aeda4 | 191 | if (input_objects->number_of_input_objects() == 0) |
8851ecca | 192 | set_parameters_target(¶meters->default_target()); |
2c0aeda4 | 193 | |
fe9a4c12 ILT |
194 | int thread_count = options.thread_count_middle(); |
195 | if (thread_count == 0) | |
fbfba508 | 196 | thread_count = std::max(2, input_objects->number_of_input_objects()); |
fe9a4c12 ILT |
197 | workqueue->set_thread_count(thread_count); |
198 | ||
b3b74ddc | 199 | // Now we have seen all the input files. |
436ca963 | 200 | const bool doing_static_link = (!input_objects->any_dynamic() |
8851ecca | 201 | && !parameters->options().shared()); |
4eff2974 ILT |
202 | set_parameters_doing_static_link(doing_static_link); |
203 | if (!doing_static_link && options.is_static()) | |
204 | { | |
205 | // We print out just the first .so we see; there may be others. | |
4e1e25e0 | 206 | gold_assert(input_objects->dynobj_begin() != input_objects->dynobj_end()); |
75f2446e ILT |
207 | gold_error(_("cannot mix -static with dynamic object %s"), |
208 | (*input_objects->dynobj_begin())->name().c_str()); | |
4eff2974 | 209 | } |
8851ecca | 210 | if (!doing_static_link && parameters->options().relocatable()) |
6a74a719 ILT |
211 | gold_error(_("cannot mix -r with dynamic object %s"), |
212 | (*input_objects->dynobj_begin())->name().c_str()); | |
516cb3d0 | 213 | if (!doing_static_link |
7cc619c3 | 214 | && options.oformat_enum() != General_options::OBJECT_FORMAT_ELF) |
516cb3d0 ILT |
215 | gold_fatal(_("cannot use non-ELF output format with dynamic object %s"), |
216 | (*input_objects->dynobj_begin())->name().c_str()); | |
b3b74ddc | 217 | |
494e05f4 ILT |
218 | if (is_debugging_enabled(DEBUG_SCRIPT)) |
219 | layout->script_options()->print(stderr); | |
220 | ||
e2827e5f ILT |
221 | // For each dynamic object, record whether we've seen all the |
222 | // dynamic objects that it depends upon. | |
223 | input_objects->check_dynamic_dependencies(); | |
224 | ||
70e654ba ILT |
225 | // See if any of the input definitions violate the One Definition Rule. |
226 | // TODO: if this is too slow, do this as a task, rather than inline. | |
17a1d0a9 | 227 | symtab->detect_odr_violations(task, options.output_file_name()); |
70e654ba | 228 | |
919ed24c ILT |
229 | // Create any output sections required by any linker script. |
230 | layout->create_script_sections(); | |
231 | ||
a3ad94ed ILT |
232 | // Define some sections and symbols needed for a dynamic link. This |
233 | // handles some cases we want to see before we read the relocs. | |
9b07f471 | 234 | layout->create_initial_dynamic_sections(symtab); |
a3ad94ed | 235 | |
a445fddf ILT |
236 | // Define symbols from any linker scripts. |
237 | layout->define_script_symbols(symtab); | |
238 | ||
f3e9c5c5 ILT |
239 | // Add any symbols named with -u options to the symbol table. |
240 | symtab->add_undefined_symbols_from_command_line(); | |
241 | ||
154e0e9a ILT |
242 | // Attach sections to segments. |
243 | layout->attach_sections_to_segments(); | |
244 | ||
8851ecca | 245 | if (!parameters->options().relocatable()) |
6a74a719 ILT |
246 | { |
247 | // Predefine standard symbols. | |
248 | define_standard_symbols(symtab, layout); | |
ead1e424 | 249 | |
6a74a719 ILT |
250 | // Define __start and __stop symbols for output sections where |
251 | // appropriate. | |
252 | layout->define_section_symbols(symtab); | |
253 | } | |
bfd58944 | 254 | |
755ab8af ILT |
255 | // Make sure we have symbols for any required group signatures. |
256 | layout->define_group_signatures(symtab); | |
257 | ||
92e059d8 ILT |
258 | // Read the relocations of the input files. We do this to find |
259 | // which symbols are used by relocations which require a GOT and/or | |
260 | // a PLT entry, or a COPY reloc. When we implement garbage | |
261 | // collection we will do it here by reading the relocations in a | |
262 | // breadth first search by references. | |
263 | // | |
264 | // We could also read the relocations during the first pass, and | |
265 | // mark symbols at that time. That is how the old GNU linker works. | |
266 | // Doing that is more complex, since we may later decide to discard | |
267 | // some of the sections, and thus change our minds about the types | |
268 | // of references made to the symbols. | |
17a1d0a9 ILT |
269 | Task_token* blocker = new Task_token(true); |
270 | Task_token* symtab_lock = new Task_token(false); | |
f6ce93d6 ILT |
271 | for (Input_objects::Relobj_iterator p = input_objects->relobj_begin(); |
272 | p != input_objects->relobj_end(); | |
92e059d8 ILT |
273 | ++p) |
274 | { | |
275 | // We can read and process the relocations in any order. But we | |
276 | // only want one task to write to the symbol table at a time. | |
277 | // So we queue up a task for each object to read the | |
278 | // relocations. That task will in turn queue a task to wait | |
279 | // until it can write to the symbol table. | |
280 | blocker->add_blocker(); | |
ead1e424 ILT |
281 | workqueue->queue(new Read_relocs(options, symtab, layout, *p, |
282 | symtab_lock, blocker)); | |
92e059d8 ILT |
283 | } |
284 | ||
285 | // Allocate common symbols. This requires write access to the | |
286 | // symbol table, but is independent of the relocation processing. | |
0dfbdef4 | 287 | if (parameters->options().define_common()) |
6a74a719 ILT |
288 | { |
289 | blocker->add_blocker(); | |
7d9e3d98 ILT |
290 | workqueue->queue(new Allocate_commons_task(symtab, layout, mapfile, |
291 | symtab_lock, blocker)); | |
6a74a719 | 292 | } |
92e059d8 ILT |
293 | |
294 | // When all those tasks are complete, we can start laying out the | |
295 | // output file. | |
8851ecca ILT |
296 | // TODO(csilvers): figure out a more principled way to get the target |
297 | Target* target = const_cast<Target*>(¶meters->target()); | |
92e059d8 ILT |
298 | workqueue->queue(new Task_function(new Layout_task_runner(options, |
299 | input_objects, | |
300 | symtab, | |
8851ecca | 301 | target, |
7d9e3d98 ILT |
302 | layout, |
303 | mapfile), | |
c7912668 ILT |
304 | blocker, |
305 | "Task_function Layout_task_runner")); | |
92e059d8 | 306 | } |
61ba1cf9 ILT |
307 | |
308 | // Queue up the final set of tasks. This is called at the end of | |
309 | // Layout_task. | |
310 | ||
311 | void | |
312 | queue_final_tasks(const General_options& options, | |
313 | const Input_objects* input_objects, | |
314 | const Symbol_table* symtab, | |
27bc2bce | 315 | Layout* layout, |
61ba1cf9 ILT |
316 | Workqueue* workqueue, |
317 | Output_file* of) | |
318 | { | |
fe9a4c12 ILT |
319 | int thread_count = options.thread_count_final(); |
320 | if (thread_count == 0) | |
fbfba508 | 321 | thread_count = std::max(2, input_objects->number_of_input_objects()); |
fe9a4c12 ILT |
322 | workqueue->set_thread_count(thread_count); |
323 | ||
17a1d0a9 ILT |
324 | bool any_postprocessing_sections = layout->any_postprocessing_sections(); |
325 | ||
730cdc88 ILT |
326 | // Use a blocker to wait until all the input sections have been |
327 | // written out. | |
17a1d0a9 ILT |
328 | Task_token* input_sections_blocker = NULL; |
329 | if (!any_postprocessing_sections) | |
330 | input_sections_blocker = new Task_token(true); | |
730cdc88 ILT |
331 | |
332 | // Use a blocker to block any objects which have to wait for the | |
333 | // output sections to complete before they can apply relocations. | |
17a1d0a9 | 334 | Task_token* output_sections_blocker = new Task_token(true); |
730cdc88 | 335 | |
61ba1cf9 | 336 | // Use a blocker to block the final cleanup task. |
17a1d0a9 | 337 | Task_token* final_blocker = new Task_token(true); |
61ba1cf9 ILT |
338 | |
339 | // Queue a task to write out the symbol table. | |
5fe2a0f5 | 340 | final_blocker->add_blocker(); |
d491d34e ILT |
341 | workqueue->queue(new Write_symbols_task(layout, |
342 | symtab, | |
5fe2a0f5 ILT |
343 | input_objects, |
344 | layout->sympool(), | |
345 | layout->dynpool(), | |
346 | of, | |
347 | final_blocker)); | |
61ba1cf9 | 348 | |
730cdc88 ILT |
349 | // Queue a task to write out the output sections. |
350 | output_sections_blocker->add_blocker(); | |
351 | final_blocker->add_blocker(); | |
352 | workqueue->queue(new Write_sections_task(layout, of, output_sections_blocker, | |
353 | final_blocker)); | |
354 | ||
61ba1cf9 ILT |
355 | // Queue a task to write out everything else. |
356 | final_blocker->add_blocker(); | |
9025d29d | 357 | workqueue->queue(new Write_data_task(layout, symtab, of, final_blocker)); |
61ba1cf9 | 358 | |
17a1d0a9 ILT |
359 | // Queue a task for each input object to relocate the sections and |
360 | // write out the local symbols. | |
361 | for (Input_objects::Relobj_iterator p = input_objects->relobj_begin(); | |
362 | p != input_objects->relobj_end(); | |
363 | ++p) | |
364 | { | |
365 | if (input_sections_blocker != NULL) | |
366 | input_sections_blocker->add_blocker(); | |
367 | final_blocker->add_blocker(); | |
368 | workqueue->queue(new Relocate_task(options, symtab, layout, *p, of, | |
369 | input_sections_blocker, | |
370 | output_sections_blocker, | |
371 | final_blocker)); | |
372 | } | |
373 | ||
730cdc88 | 374 | // Queue a task to write out the output sections which depend on |
17a1d0a9 ILT |
375 | // input sections. If there are any sections which require |
376 | // postprocessing, then we need to do this last, since it may resize | |
377 | // the output file. | |
378 | if (!any_postprocessing_sections) | |
379 | { | |
380 | final_blocker->add_blocker(); | |
381 | Task* t = new Write_after_input_sections_task(layout, of, | |
382 | input_sections_blocker, | |
383 | final_blocker); | |
384 | workqueue->queue(t); | |
385 | } | |
386 | else | |
387 | { | |
388 | Task_token *new_final_blocker = new Task_token(true); | |
389 | new_final_blocker->add_blocker(); | |
390 | Task* t = new Write_after_input_sections_task(layout, of, | |
391 | final_blocker, | |
392 | new_final_blocker); | |
393 | workqueue->queue(t); | |
394 | final_blocker = new_final_blocker; | |
395 | } | |
730cdc88 | 396 | |
61ba1cf9 ILT |
397 | // Queue a task to close the output file. This will be blocked by |
398 | // FINAL_BLOCKER. | |
516cb3d0 ILT |
399 | workqueue->queue(new Task_function(new Close_task_runner(&options, layout, |
400 | of), | |
c7912668 ILT |
401 | final_blocker, |
402 | "Task_function Close_task_runner")); | |
61ba1cf9 ILT |
403 | } |
404 | ||
405 | } // End namespace gold. |