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0e879927 ILT |
1 | // inremental.cc -- incremental linking support for gold |
2 | ||
3 | // Copyright 2009 Free Software Foundation, Inc. | |
4 | // Written by Mikolaj Zalewski <mikolajz@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 | ||
23 | #include "gold.h" | |
c549a694 ILT |
24 | |
25 | #include <cstdarg> | |
26 | ||
0e879927 | 27 | #include "elfcpp.h" |
3ce2c28e ILT |
28 | #include "output.h" |
29 | #include "incremental.h" | |
98fa85cb | 30 | #include "archive.h" |
44453f85 | 31 | #include "output.h" |
c549a694 | 32 | #include "target-select.h" |
0e879927 | 33 | |
0e879927 ILT |
34 | namespace gold { |
35 | ||
36 | // Version information. Will change frequently during the development, later | |
37 | // we could think about backward (and forward?) compatibility. | |
c4aa1e2d | 38 | const unsigned int INCREMENTAL_LINK_VERSION = 1; |
0e879927 | 39 | |
c549a694 ILT |
40 | // Inform the user why we don't do an incremental link. Not called in |
41 | // the obvious case of missing output file. TODO: Is this helpful? | |
42 | ||
43 | void | |
44 | vexplain_no_incremental(const char* format, va_list args) | |
45 | { | |
46 | char* buf = NULL; | |
47 | if (vasprintf(&buf, format, args) < 0) | |
48 | gold_nomem(); | |
49 | gold_info(_("the link might take longer: " | |
50 | "cannot perform incremental link: %s"), buf); | |
51 | free(buf); | |
52 | } | |
53 | ||
54 | void | |
55 | explain_no_incremental(const char* format, ...) | |
56 | { | |
57 | va_list args; | |
58 | va_start(args, format); | |
59 | vexplain_no_incremental(format, args); | |
60 | va_end(args); | |
61 | } | |
62 | ||
63 | // Report an error. | |
64 | ||
65 | void | |
66 | Incremental_binary::error(const char* format, ...) const | |
67 | { | |
68 | va_list args; | |
69 | va_start(args, format); | |
70 | // Current code only checks if the file can be used for incremental linking, | |
71 | // so errors shouldn't fail the build, but only result in a fallback to a | |
72 | // full build. | |
73 | // TODO: when we implement incremental editing of the file, we may need a | |
74 | // flag that will cause errors to be treated seriously. | |
75 | vexplain_no_incremental(format, args); | |
76 | va_end(args); | |
77 | } | |
78 | ||
79 | template<int size, bool big_endian> | |
80 | bool | |
81 | Sized_incremental_binary<size, big_endian>::do_find_incremental_inputs_section( | |
c4aa1e2d ILT |
82 | Location* location, |
83 | unsigned int* strtab_shndx) | |
c549a694 ILT |
84 | { |
85 | unsigned int shndx = this->elf_file_.find_section_by_type( | |
86 | elfcpp::SHT_GNU_INCREMENTAL_INPUTS); | |
87 | if (shndx == elfcpp::SHN_UNDEF) // Not found. | |
88 | return false; | |
c4aa1e2d | 89 | *strtab_shndx = this->elf_file_.section_link(shndx); |
c549a694 ILT |
90 | *location = this->elf_file_.section_contents(shndx); |
91 | return true; | |
92 | } | |
93 | ||
c4aa1e2d ILT |
94 | template<int size, bool big_endian> |
95 | bool | |
96 | Sized_incremental_binary<size, big_endian>::do_check_inputs( | |
97 | Incremental_inputs* incremental_inputs) | |
98 | { | |
99 | const int entry_size = | |
100 | Incremental_inputs_entry_write<size, big_endian>::data_size; | |
101 | const int header_size = | |
102 | Incremental_inputs_header_write<size, big_endian>::data_size; | |
103 | ||
104 | unsigned int strtab_shndx; | |
105 | Location location; | |
106 | ||
107 | if (!do_find_incremental_inputs_section(&location, &strtab_shndx)) | |
108 | { | |
109 | explain_no_incremental(_("no incremental data from previous build")); | |
110 | return false; | |
111 | } | |
112 | if (location.data_size < header_size | |
113 | || strtab_shndx >= this->elf_file_.shnum() | |
114 | || this->elf_file_.section_type(strtab_shndx) != elfcpp::SHT_STRTAB) | |
115 | { | |
116 | explain_no_incremental(_("invalid incremental build data")); | |
117 | return false; | |
118 | } | |
119 | ||
120 | Location strtab_location(this->elf_file_.section_contents(strtab_shndx)); | |
121 | View data_view(view(location)); | |
122 | View strtab_view(view(strtab_location)); | |
123 | elfcpp::Elf_strtab strtab(strtab_view.data(), strtab_location.data_size); | |
124 | Incremental_inputs_header<size, big_endian> header(data_view.data()); | |
125 | ||
126 | if (header.get_version() != INCREMENTAL_LINK_VERSION) | |
127 | { | |
128 | explain_no_incremental(_("different version of incremental build data")); | |
129 | return false; | |
130 | } | |
131 | ||
132 | const char* command_line; | |
133 | // We divide instead of multiplying to make sure there is no integer | |
134 | // overflow. | |
135 | size_t max_input_entries = (location.data_size - header_size) / entry_size; | |
136 | if (header.get_input_file_count() > max_input_entries | |
137 | || !strtab.get_c_string(header.get_command_line_offset(), &command_line)) | |
138 | { | |
139 | explain_no_incremental(_("invalid incremental build data")); | |
140 | return false; | |
141 | } | |
142 | ||
143 | if (incremental_inputs->command_line() != command_line) | |
144 | { | |
145 | explain_no_incremental(_("command line changed")); | |
146 | return false; | |
147 | } | |
148 | ||
149 | // TODO: compare incremental_inputs->inputs() with entries in data_view. | |
150 | return true; | |
151 | } | |
152 | ||
c549a694 ILT |
153 | namespace |
154 | { | |
155 | ||
156 | // Create a Sized_incremental_binary object of the specified size and | |
157 | // endianness. Fails if the target architecture is not supported. | |
158 | ||
159 | template<int size, bool big_endian> | |
160 | Incremental_binary* | |
161 | make_sized_incremental_binary(Output_file* file, | |
162 | const elfcpp::Ehdr<size, big_endian>& ehdr) | |
163 | { | |
164 | Target* target = select_target(ehdr.get_e_machine(), size, big_endian, | |
165 | ehdr.get_e_ident()[elfcpp::EI_OSABI], | |
166 | ehdr.get_e_ident()[elfcpp::EI_ABIVERSION]); | |
167 | if (target == NULL) | |
168 | { | |
169 | explain_no_incremental(_("unsupported ELF machine number %d"), | |
170 | ehdr.get_e_machine()); | |
171 | return NULL; | |
172 | } | |
173 | ||
3aec4f9c RÁE |
174 | if (!parameters->target_valid()) |
175 | set_parameters_target(target); | |
176 | else if (target != ¶meters->target()) | |
177 | gold_error(_("%s: incompatible target"), file->filename()); | |
178 | ||
c549a694 ILT |
179 | return new Sized_incremental_binary<size, big_endian>(file, ehdr, target); |
180 | } | |
181 | ||
182 | } // End of anonymous namespace. | |
183 | ||
184 | // Create an Incremental_binary object for FILE. Returns NULL is this is not | |
185 | // possible, e.g. FILE is not an ELF file or has an unsupported target. FILE | |
186 | // should be opened. | |
187 | ||
188 | Incremental_binary* | |
189 | open_incremental_binary(Output_file* file) | |
190 | { | |
191 | off_t filesize = file->filesize(); | |
192 | int want = elfcpp::Elf_recognizer::max_header_size; | |
193 | if (filesize < want) | |
194 | want = filesize; | |
195 | ||
196 | const unsigned char* p = file->get_input_view(0, want); | |
197 | if (!elfcpp::Elf_recognizer::is_elf_file(p, want)) | |
198 | { | |
199 | explain_no_incremental(_("output is not an ELF file.")); | |
200 | return NULL; | |
201 | } | |
202 | ||
ac33a407 DK |
203 | int size = 0; |
204 | bool big_endian = false; | |
c549a694 ILT |
205 | std::string error; |
206 | if (!elfcpp::Elf_recognizer::is_valid_header(p, want, &size, &big_endian, | |
207 | &error)) | |
208 | { | |
209 | explain_no_incremental(error.c_str()); | |
210 | return NULL; | |
211 | } | |
212 | ||
213 | Incremental_binary* result = NULL; | |
214 | if (size == 32) | |
215 | { | |
216 | if (big_endian) | |
217 | { | |
218 | #ifdef HAVE_TARGET_32_BIG | |
219 | result = make_sized_incremental_binary<32, true>( | |
220 | file, elfcpp::Ehdr<32, true>(p)); | |
221 | #else | |
222 | explain_no_incremental(_("unsupported file: 32-bit, big-endian")); | |
223 | #endif | |
224 | } | |
225 | else | |
226 | { | |
227 | #ifdef HAVE_TARGET_32_LITTLE | |
228 | result = make_sized_incremental_binary<32, false>( | |
229 | file, elfcpp::Ehdr<32, false>(p)); | |
230 | #else | |
231 | explain_no_incremental(_("unsupported file: 32-bit, little-endian")); | |
232 | #endif | |
233 | } | |
234 | } | |
235 | else if (size == 64) | |
236 | { | |
237 | if (big_endian) | |
238 | { | |
239 | #ifdef HAVE_TARGET_64_BIG | |
240 | result = make_sized_incremental_binary<64, true>( | |
241 | file, elfcpp::Ehdr<64, true>(p)); | |
242 | #else | |
243 | explain_no_incremental(_("unsupported file: 64-bit, big-endian")); | |
244 | #endif | |
245 | } | |
246 | else | |
247 | { | |
248 | #ifdef HAVE_TARGET_64_LITTLE | |
249 | result = make_sized_incremental_binary<64, false>( | |
250 | file, elfcpp::Ehdr<64, false>(p)); | |
251 | #else | |
252 | explain_no_incremental(_("unsupported file: 64-bit, little-endian")); | |
253 | #endif | |
254 | } | |
255 | } | |
256 | else | |
257 | gold_unreachable(); | |
258 | ||
259 | return result; | |
260 | } | |
261 | ||
44453f85 ILT |
262 | // Analyzes the output file to check if incremental linking is possible and |
263 | // (to be done) what files need to be relinked. | |
264 | ||
265 | bool | |
266 | Incremental_checker::can_incrementally_link_output_file() | |
267 | { | |
268 | Output_file output(this->output_name_); | |
269 | if (!output.open_for_modification()) | |
270 | return false; | |
c549a694 ILT |
271 | Incremental_binary* binary = open_incremental_binary(&output); |
272 | if (binary == NULL) | |
273 | return false; | |
c4aa1e2d | 274 | return binary->check_inputs(this->incremental_inputs_); |
44453f85 ILT |
275 | } |
276 | ||
3ce2c28e ILT |
277 | // Add the command line to the string table, setting |
278 | // command_line_key_. In incremental builds, the command line is | |
279 | // stored in .gnu_incremental_inputs so that the next linker run can | |
280 | // check if the command line options didn't change. | |
281 | ||
282 | void | |
283 | Incremental_inputs::report_command_line(int argc, const char* const* argv) | |
284 | { | |
285 | // Always store 'gold' as argv[0] to avoid a full relink if the user used a | |
286 | // different path to the linker. | |
287 | std::string args("gold"); | |
288 | // Copied from collect_argv in main.cc. | |
289 | for (int i = 1; i < argc; ++i) | |
290 | { | |
b19b0c6d ILT |
291 | // Adding/removing these options should result in a full relink. |
292 | if (strcmp(argv[i], "--incremental-changed") == 0 | |
293 | || strcmp(argv[i], "--incremental-unchanged") == 0 | |
294 | || strcmp(argv[i], "--incremental-unknown") == 0) | |
295 | continue; | |
296 | ||
3ce2c28e ILT |
297 | args.append(" '"); |
298 | // Now append argv[i], but with all single-quotes escaped | |
299 | const char* argpos = argv[i]; | |
300 | while (1) | |
301 | { | |
302 | const int len = strcspn(argpos, "'"); | |
303 | args.append(argpos, len); | |
304 | if (argpos[len] == '\0') | |
305 | break; | |
306 | args.append("'\"'\"'"); | |
307 | argpos += len + 1; | |
308 | } | |
309 | args.append("'"); | |
310 | } | |
c4aa1e2d ILT |
311 | |
312 | this->command_line_ = args; | |
313 | this->strtab_->add(this->command_line_.c_str(), false, | |
314 | &this->command_line_key_); | |
3ce2c28e ILT |
315 | } |
316 | ||
072fe7ce ILT |
317 | // Record that the input argument INPUT is an achive ARCHIVE. This is |
318 | // called by Read_symbols after finding out the type of the file. | |
319 | ||
320 | void | |
321 | Incremental_inputs::report_archive(const Input_argument* input, | |
322 | Archive* archive) | |
323 | { | |
324 | Hold_lock hl(*this->lock_); | |
325 | ||
326 | Input_info info; | |
327 | info.type = INCREMENTAL_INPUT_ARCHIVE; | |
328 | info.archive = archive; | |
98fa85cb ILT |
329 | info.mtime = archive->file().get_mtime(); |
330 | this->inputs_map_.insert(std::make_pair(input, info)); | |
072fe7ce ILT |
331 | } |
332 | ||
333 | // Record that the input argument INPUT is an object OBJ. This is | |
334 | // called by Read_symbols after finding out the type of the file. | |
335 | ||
336 | void | |
337 | Incremental_inputs::report_object(const Input_argument* input, | |
338 | Object* obj) | |
339 | { | |
340 | Hold_lock hl(*this->lock_); | |
341 | ||
342 | Input_info info; | |
343 | info.type = (obj->is_dynamic() | |
344 | ? INCREMENTAL_INPUT_SHARED_LIBRARY | |
345 | : INCREMENTAL_INPUT_OBJECT); | |
346 | info.object = obj; | |
98fa85cb ILT |
347 | info.mtime = obj->input_file()->file().get_mtime(); |
348 | this->inputs_map_.insert(std::make_pair(input, info)); | |
072fe7ce ILT |
349 | } |
350 | ||
351 | // Record that the input argument INPUT is an script SCRIPT. This is | |
352 | // called by read_script after parsing the script and reading the list | |
353 | // of inputs added by this script. | |
354 | ||
355 | void | |
356 | Incremental_inputs::report_script(const Input_argument* input, | |
98fa85cb | 357 | Timespec mtime, |
072fe7ce ILT |
358 | Script_info* script) |
359 | { | |
360 | Hold_lock hl(*this->lock_); | |
361 | ||
362 | Input_info info; | |
363 | info.type = INCREMENTAL_INPUT_SCRIPT; | |
364 | info.script = script; | |
98fa85cb ILT |
365 | info.mtime = mtime; |
366 | this->inputs_map_.insert(std::make_pair(input, info)); | |
072fe7ce ILT |
367 | } |
368 | ||
369 | // Compute indexes in the order in which the inputs should appear in | |
370 | // .gnu_incremental_inputs. This needs to be done after all the | |
371 | // scripts are parsed. The function is first called for the command | |
372 | // line inputs arguments and may call itself recursively for e.g. a | |
373 | // list of elements of a group or a list of inputs added by a script. | |
374 | // The [BEGIN; END) interval to analyze and *INDEX is the current | |
375 | // value of the index (that will be updated). | |
376 | ||
377 | void | |
378 | Incremental_inputs::finalize_inputs( | |
379 | Input_argument_list::const_iterator begin, | |
380 | Input_argument_list::const_iterator end, | |
381 | unsigned int* index) | |
382 | { | |
383 | for (Input_argument_list::const_iterator p = begin; p != end; ++p) | |
384 | { | |
385 | if (p->is_group()) | |
386 | { | |
387 | finalize_inputs(p->group()->begin(), p->group()->end(), index); | |
388 | continue; | |
389 | } | |
390 | ||
98fa85cb | 391 | Inputs_info_map::iterator it = this->inputs_map_.find(&(*p)); |
072fe7ce | 392 | // TODO: turn it into an assert when the code will be more stable. |
98fa85cb | 393 | if (it == this->inputs_map_.end()) |
072fe7ce ILT |
394 | { |
395 | gold_error("internal error: %s: incremental build info not provided", | |
396 | (p->is_file() ? p->file().name() : "[group]")); | |
397 | continue; | |
398 | } | |
399 | Input_info* info = &it->second; | |
400 | info->index = *index; | |
401 | (*index)++; | |
402 | this->strtab_->add(p->file().name(), false, &info->filename_key); | |
403 | if (info->type == INCREMENTAL_INPUT_SCRIPT) | |
404 | { | |
405 | finalize_inputs(info->script->inputs()->begin(), | |
406 | info->script->inputs()->end(), | |
407 | index); | |
408 | } | |
409 | } | |
410 | } | |
411 | ||
3ce2c28e ILT |
412 | // Finalize the incremental link information. Called from |
413 | // Layout::finalize. | |
414 | ||
415 | void | |
416 | Incremental_inputs::finalize() | |
417 | { | |
072fe7ce ILT |
418 | unsigned int index = 0; |
419 | finalize_inputs(this->inputs_->begin(), this->inputs_->end(), &index); | |
420 | ||
421 | // Sanity check. | |
98fa85cb ILT |
422 | for (Inputs_info_map::const_iterator p = this->inputs_map_.begin(); |
423 | p != this->inputs_map_.end(); | |
072fe7ce ILT |
424 | ++p) |
425 | { | |
426 | gold_assert(p->second.filename_key != 0); | |
427 | } | |
428 | ||
3ce2c28e ILT |
429 | this->strtab_->set_string_offsets(); |
430 | } | |
431 | ||
432 | // Create the content of the .gnu_incremental_inputs section. | |
433 | ||
434 | Output_section_data* | |
435 | Incremental_inputs::create_incremental_inputs_section_data() | |
436 | { | |
437 | switch (parameters->size_and_endianness()) | |
438 | { | |
439 | #ifdef HAVE_TARGET_32_LITTLE | |
440 | case Parameters::TARGET_32_LITTLE: | |
441 | return this->sized_create_inputs_section_data<32, false>(); | |
442 | #endif | |
443 | #ifdef HAVE_TARGET_32_BIG | |
444 | case Parameters::TARGET_32_BIG: | |
445 | return this->sized_create_inputs_section_data<32, true>(); | |
446 | #endif | |
447 | #ifdef HAVE_TARGET_64_LITTLE | |
448 | case Parameters::TARGET_64_LITTLE: | |
449 | return this->sized_create_inputs_section_data<64, false>(); | |
450 | #endif | |
451 | #ifdef HAVE_TARGET_64_BIG | |
452 | case Parameters::TARGET_64_BIG: | |
453 | return this->sized_create_inputs_section_data<64, true>(); | |
454 | #endif | |
455 | default: | |
456 | gold_unreachable(); | |
072fe7ce | 457 | } |
3ce2c28e ILT |
458 | } |
459 | ||
460 | // Sized creation of .gnu_incremental_inputs section. | |
461 | ||
462 | template<int size, bool big_endian> | |
463 | Output_section_data* | |
464 | Incremental_inputs::sized_create_inputs_section_data() | |
072fe7ce ILT |
465 | { |
466 | const int entry_size = | |
467 | Incremental_inputs_entry_write<size, big_endian>::data_size; | |
468 | const int header_size = | |
3ce2c28e | 469 | Incremental_inputs_header_write<size, big_endian>::data_size; |
072fe7ce ILT |
470 | |
471 | unsigned int sz = header_size + entry_size * this->inputs_map_.size(); | |
3ce2c28e | 472 | unsigned char* buffer = new unsigned char[sz]; |
072fe7ce ILT |
473 | unsigned char* inputs_base = buffer + header_size; |
474 | ||
3ce2c28e | 475 | Incremental_inputs_header_write<size, big_endian> header_writer(buffer); |
3ce2c28e ILT |
476 | gold_assert(this->command_line_key_ > 0); |
477 | int cmd_offset = this->strtab_->get_offset_from_key(this->command_line_key_); | |
072fe7ce | 478 | |
3ce2c28e | 479 | header_writer.put_version(INCREMENTAL_LINK_VERSION); |
072fe7ce | 480 | header_writer.put_input_file_count(this->inputs_map_.size()); |
3ce2c28e ILT |
481 | header_writer.put_command_line_offset(cmd_offset); |
482 | header_writer.put_reserved(0); | |
072fe7ce ILT |
483 | |
484 | for (Inputs_info_map::const_iterator it = this->inputs_map_.begin(); | |
485 | it != this->inputs_map_.end(); | |
486 | ++it) | |
487 | { | |
488 | gold_assert(it->second.index < this->inputs_map_.size()); | |
489 | ||
490 | unsigned char* entry_buffer = | |
491 | inputs_base + it->second.index * entry_size; | |
492 | Incremental_inputs_entry_write<size, big_endian> entry(entry_buffer); | |
493 | int filename_offset = | |
494 | this->strtab_->get_offset_from_key(it->second.filename_key); | |
495 | entry.put_filename_offset(filename_offset); | |
a45500ae RÁE |
496 | switch (it->second.type) |
497 | { | |
498 | case INCREMENTAL_INPUT_SCRIPT: | |
499 | entry.put_data_offset(0); | |
500 | break; | |
501 | case INCREMENTAL_INPUT_ARCHIVE: | |
502 | case INCREMENTAL_INPUT_OBJECT: | |
503 | case INCREMENTAL_INPUT_SHARED_LIBRARY: | |
504 | // TODO: add per input data. Currently we store | |
505 | // an out-of-bounds offset for future version of gold to reject | |
506 | // such an incremental_inputs section. | |
507 | entry.put_data_offset(0xffffffff); | |
508 | break; | |
509 | default: | |
510 | gold_unreachable(); | |
511 | } | |
98fa85cb ILT |
512 | entry.put_timestamp_sec(it->second.mtime.seconds); |
513 | entry.put_timestamp_nsec(it->second.mtime.nanoseconds); | |
072fe7ce ILT |
514 | entry.put_input_type(it->second.type); |
515 | entry.put_reserved(0); | |
516 | } | |
517 | ||
3ce2c28e | 518 | return new Output_data_const_buffer(buffer, sz, 8, |
072fe7ce | 519 | "** incremental link inputs list"); |
3ce2c28e ILT |
520 | } |
521 | ||
c549a694 ILT |
522 | // Instantiate the templates we need. |
523 | ||
524 | #ifdef HAVE_TARGET_32_LITTLE | |
525 | template | |
526 | class Sized_incremental_binary<32, false>; | |
527 | #endif | |
528 | ||
529 | #ifdef HAVE_TARGET_32_BIG | |
530 | template | |
531 | class Sized_incremental_binary<32, true>; | |
532 | #endif | |
533 | ||
534 | #ifdef HAVE_TARGET_64_LITTLE | |
535 | template | |
536 | class Sized_incremental_binary<64, false>; | |
537 | #endif | |
538 | ||
539 | #ifdef HAVE_TARGET_64_BIG | |
540 | template | |
541 | class Sized_incremental_binary<64, true>; | |
542 | #endif | |
543 | ||
0e879927 | 544 | } // End namespace gold. |