2009-12-02 Rafael Avila de Espindola <espindola@google.com>
[binutils.git] / gold / incremental.cc
blobe89372a076337f185fcdc29c18f499e2027dd84b
1 // inremental.cc -- incremental linking support for gold
3 // Copyright 2009 Free Software Foundation, Inc.
4 // Written by Mikolaj Zalewski <mikolajz@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.
23 #include "gold.h"
25 #include <cstdarg>
27 #include "elfcpp.h"
28 #include "output.h"
29 #include "incremental.h"
30 #include "archive.h"
31 #include "output.h"
32 #include "target-select.h"
34 using elfcpp::Convert;
36 namespace gold {
38 // Version information. Will change frequently during the development, later
39 // we could think about backward (and forward?) compatibility.
40 const unsigned int INCREMENTAL_LINK_VERSION = 1;
42 // Accessors.
44 // Reader class for .gnu_incremental_inputs header. See
45 // Incremental_inputs_header_data for fields descriptions.
47 template<int size, bool big_endian>
48 class Incremental_inputs_header
50 private:
51 typedef Incremental_inputs_header_data Data_type;
53 public:
54 Incremental_inputs_header(const unsigned char *p)
55 : p_(reinterpret_cast<const Data_type*>(p))
56 { }
58 static const int data_size = sizeof(Data_type);
60 elfcpp::Elf_Word
61 get_version() const
62 { return Convert<32, big_endian>::convert_host(this->p_->version); }
64 elfcpp::Elf_Word
65 get_input_file_count() const
66 { return Convert<32, big_endian>::convert_host(this->p_->input_file_count); }
68 elfcpp::Elf_Word
69 get_command_line_offset() const
70 { return Convert<32, big_endian>::convert_host(this->p_->command_line_offset); }
72 elfcpp::Elf_Word
73 get_reserved() const
74 { return Convert<32, big_endian>::convert_host(this->p_->reserved); }
76 private:
77 const Data_type* p_;
80 // Writer class for .gnu_incremental_inputs header. See
81 // Incremental_inputs_header_data for fields descriptions.
83 template<int size, bool big_endian>
84 class Incremental_inputs_header_write
86 private:
87 typedef Incremental_inputs_header_data Data_type;
89 public:
90 Incremental_inputs_header_write(unsigned char *p)
91 : p_(reinterpret_cast<Data_type*>(p))
92 { }
94 static const int data_size = sizeof(Data_type);
96 void
97 put_version(elfcpp::Elf_Word v)
98 { this->p_->version = Convert<32, big_endian>::convert_host(v); }
100 void
101 put_input_file_count(elfcpp::Elf_Word v)
102 { this->p_->input_file_count = Convert<32, big_endian>::convert_host(v); }
104 void
105 put_command_line_offset(elfcpp::Elf_Word v)
106 { this->p_->command_line_offset = Convert<32, big_endian>::convert_host(v); }
108 void
109 put_reserved(elfcpp::Elf_Word v)
110 { this->p_->reserved = Convert<32, big_endian>::convert_host(v); }
112 private:
113 Data_type* p_;
116 // Reader class for an .gnu_incremental_inputs entry. See
117 // Incremental_inputs_entry_data for fields descriptions.
118 template<int size, bool big_endian>
119 class Incremental_inputs_entry
121 private:
122 typedef Incremental_inputs_entry_data Data_type;
124 public:
125 Incremental_inputs_entry(const unsigned char *p)
126 : p_(reinterpret_cast<const Data_type*>(p))
129 static const int data_size = sizeof(Data_type);
131 elfcpp::Elf_Word
132 get_filename_offset(elfcpp::Elf_Word v)
133 { return Convert<32, big_endian>::convert_host(this->p_->filename_offset); }
135 elfcpp::Elf_Word
136 get_data_offset(elfcpp::Elf_Word v)
137 { return Convert<32, big_endian>::convert_host(this->p_->data_offset); }
139 elfcpp::Elf_Xword
140 get_timestamp_sec(elfcpp::Elf_Xword v)
141 { return Convert<64, big_endian>::convert_host(this->p_->timestamp_sec); }
143 elfcpp::Elf_Word
144 get_timestamp_nsec(elfcpp::Elf_Word v)
145 { return Convert<32, big_endian>::convert_host(this->p_->timestamp_nsec); }
147 elfcpp::Elf_Word
148 get_input_type(elfcpp::Elf_Word v)
149 { return Convert<32, big_endian>::convert_host(this->p_->input_type); }
151 elfcpp::Elf_Word
152 get_reserved(elfcpp::Elf_Word v)
153 { return Convert<32, big_endian>::convert_host(this->p_->reserved); }
155 private:
156 const Data_type* p_;
159 // Writer class for an .gnu_incremental_inputs entry. See
160 // Incremental_inputs_entry_data for fields descriptions.
161 template<int size, bool big_endian>
162 class Incremental_inputs_entry_write
164 private:
165 typedef Incremental_inputs_entry_data Data_type;
167 public:
168 Incremental_inputs_entry_write(unsigned char *p)
169 : p_(reinterpret_cast<Data_type*>(p))
172 static const int data_size = sizeof(Data_type);
174 void
175 put_filename_offset(elfcpp::Elf_Word v)
176 { this->p_->filename_offset = Convert<32, big_endian>::convert_host(v); }
178 void
179 put_data_offset(elfcpp::Elf_Word v)
180 { this->p_->data_offset = Convert<32, big_endian>::convert_host(v); }
182 void
183 put_timestamp_sec(elfcpp::Elf_Xword v)
184 { this->p_->timestamp_sec = Convert<64, big_endian>::convert_host(v); }
186 void
187 put_timestamp_nsec(elfcpp::Elf_Word v)
188 { this->p_->timestamp_nsec = Convert<32, big_endian>::convert_host(v); }
190 void
191 put_input_type(elfcpp::Elf_Word v)
192 { this->p_->input_type = Convert<32, big_endian>::convert_host(v); }
194 void
195 put_reserved(elfcpp::Elf_Word v)
196 { this->p_->reserved = Convert<32, big_endian>::convert_host(v); }
198 private:
199 Data_type* p_;
202 // Inform the user why we don't do an incremental link. Not called in
203 // the obvious case of missing output file. TODO: Is this helpful?
205 void
206 vexplain_no_incremental(const char* format, va_list args)
208 char* buf = NULL;
209 if (vasprintf(&buf, format, args) < 0)
210 gold_nomem();
211 gold_info(_("the link might take longer: "
212 "cannot perform incremental link: %s"), buf);
213 free(buf);
216 void
217 explain_no_incremental(const char* format, ...)
219 va_list args;
220 va_start(args, format);
221 vexplain_no_incremental(format, args);
222 va_end(args);
225 // Report an error.
227 void
228 Incremental_binary::error(const char* format, ...) const
230 va_list args;
231 va_start(args, format);
232 // Current code only checks if the file can be used for incremental linking,
233 // so errors shouldn't fail the build, but only result in a fallback to a
234 // full build.
235 // TODO: when we implement incremental editing of the file, we may need a
236 // flag that will cause errors to be treated seriously.
237 vexplain_no_incremental(format, args);
238 va_end(args);
241 template<int size, bool big_endian>
242 bool
243 Sized_incremental_binary<size, big_endian>::do_find_incremental_inputs_section(
244 Location* location,
245 unsigned int* strtab_shndx)
247 unsigned int shndx = this->elf_file_.find_section_by_type(
248 elfcpp::SHT_GNU_INCREMENTAL_INPUTS);
249 if (shndx == elfcpp::SHN_UNDEF) // Not found.
250 return false;
251 *strtab_shndx = this->elf_file_.section_link(shndx);
252 *location = this->elf_file_.section_contents(shndx);
253 return true;
256 template<int size, bool big_endian>
257 bool
258 Sized_incremental_binary<size, big_endian>::do_check_inputs(
259 Incremental_inputs* incremental_inputs)
261 const int entry_size =
262 Incremental_inputs_entry_write<size, big_endian>::data_size;
263 const int header_size =
264 Incremental_inputs_header_write<size, big_endian>::data_size;
266 unsigned int strtab_shndx;
267 Location location;
269 if (!do_find_incremental_inputs_section(&location, &strtab_shndx))
271 explain_no_incremental(_("no incremental data from previous build"));
272 return false;
274 if (location.data_size < header_size
275 || strtab_shndx >= this->elf_file_.shnum()
276 || this->elf_file_.section_type(strtab_shndx) != elfcpp::SHT_STRTAB)
278 explain_no_incremental(_("invalid incremental build data"));
279 return false;
282 Location strtab_location(this->elf_file_.section_contents(strtab_shndx));
283 View data_view(view(location));
284 View strtab_view(view(strtab_location));
285 elfcpp::Elf_strtab strtab(strtab_view.data(), strtab_location.data_size);
286 Incremental_inputs_header<size, big_endian> header(data_view.data());
288 if (header.get_version() != INCREMENTAL_LINK_VERSION)
290 explain_no_incremental(_("different version of incremental build data"));
291 return false;
294 const char* command_line;
295 // We divide instead of multiplying to make sure there is no integer
296 // overflow.
297 size_t max_input_entries = (location.data_size - header_size) / entry_size;
298 if (header.get_input_file_count() > max_input_entries
299 || !strtab.get_c_string(header.get_command_line_offset(), &command_line))
301 explain_no_incremental(_("invalid incremental build data"));
302 return false;
305 if (incremental_inputs->command_line() != command_line)
307 explain_no_incremental(_("command line changed"));
308 return false;
311 // TODO: compare incremental_inputs->inputs() with entries in data_view.
312 return true;
315 namespace
318 // Create a Sized_incremental_binary object of the specified size and
319 // endianness. Fails if the target architecture is not supported.
321 template<int size, bool big_endian>
322 Incremental_binary*
323 make_sized_incremental_binary(Output_file* file,
324 const elfcpp::Ehdr<size, big_endian>& ehdr)
326 Target* target = select_target(ehdr.get_e_machine(), size, big_endian,
327 ehdr.get_e_ident()[elfcpp::EI_OSABI],
328 ehdr.get_e_ident()[elfcpp::EI_ABIVERSION]);
329 if (target == NULL)
331 explain_no_incremental(_("unsupported ELF machine number %d"),
332 ehdr.get_e_machine());
333 return NULL;
336 return new Sized_incremental_binary<size, big_endian>(file, ehdr, target);
339 } // End of anonymous namespace.
341 // Create an Incremental_binary object for FILE. Returns NULL is this is not
342 // possible, e.g. FILE is not an ELF file or has an unsupported target. FILE
343 // should be opened.
345 Incremental_binary*
346 open_incremental_binary(Output_file* file)
348 off_t filesize = file->filesize();
349 int want = elfcpp::Elf_recognizer::max_header_size;
350 if (filesize < want)
351 want = filesize;
353 const unsigned char* p = file->get_input_view(0, want);
354 if (!elfcpp::Elf_recognizer::is_elf_file(p, want))
356 explain_no_incremental(_("output is not an ELF file."));
357 return NULL;
360 int size = 0;
361 bool big_endian = false;
362 std::string error;
363 if (!elfcpp::Elf_recognizer::is_valid_header(p, want, &size, &big_endian,
364 &error))
366 explain_no_incremental(error.c_str());
367 return NULL;
370 Incremental_binary* result = NULL;
371 if (size == 32)
373 if (big_endian)
375 #ifdef HAVE_TARGET_32_BIG
376 result = make_sized_incremental_binary<32, true>(
377 file, elfcpp::Ehdr<32, true>(p));
378 #else
379 explain_no_incremental(_("unsupported file: 32-bit, big-endian"));
380 #endif
382 else
384 #ifdef HAVE_TARGET_32_LITTLE
385 result = make_sized_incremental_binary<32, false>(
386 file, elfcpp::Ehdr<32, false>(p));
387 #else
388 explain_no_incremental(_("unsupported file: 32-bit, little-endian"));
389 #endif
392 else if (size == 64)
394 if (big_endian)
396 #ifdef HAVE_TARGET_64_BIG
397 result = make_sized_incremental_binary<64, true>(
398 file, elfcpp::Ehdr<64, true>(p));
399 #else
400 explain_no_incremental(_("unsupported file: 64-bit, big-endian"));
401 #endif
403 else
405 #ifdef HAVE_TARGET_64_LITTLE
406 result = make_sized_incremental_binary<64, false>(
407 file, elfcpp::Ehdr<64, false>(p));
408 #else
409 explain_no_incremental(_("unsupported file: 64-bit, little-endian"));
410 #endif
413 else
414 gold_unreachable();
416 return result;
419 // Analyzes the output file to check if incremental linking is possible and
420 // (to be done) what files need to be relinked.
422 bool
423 Incremental_checker::can_incrementally_link_output_file()
425 Output_file output(this->output_name_);
426 if (!output.open_for_modification())
427 return false;
428 Incremental_binary* binary = open_incremental_binary(&output);
429 if (binary == NULL)
430 return false;
431 return binary->check_inputs(this->incremental_inputs_);
434 // Add the command line to the string table, setting
435 // command_line_key_. In incremental builds, the command line is
436 // stored in .gnu_incremental_inputs so that the next linker run can
437 // check if the command line options didn't change.
439 void
440 Incremental_inputs::report_command_line(int argc, const char* const* argv)
442 // Always store 'gold' as argv[0] to avoid a full relink if the user used a
443 // different path to the linker.
444 std::string args("gold");
445 // Copied from collect_argv in main.cc.
446 for (int i = 1; i < argc; ++i)
448 // Adding/removing these options should result in a full relink.
449 if (strcmp(argv[i], "--incremental-changed") == 0
450 || strcmp(argv[i], "--incremental-unchanged") == 0
451 || strcmp(argv[i], "--incremental-unknown") == 0)
452 continue;
454 args.append(" '");
455 // Now append argv[i], but with all single-quotes escaped
456 const char* argpos = argv[i];
457 while (1)
459 const int len = strcspn(argpos, "'");
460 args.append(argpos, len);
461 if (argpos[len] == '\0')
462 break;
463 args.append("'\"'\"'");
464 argpos += len + 1;
466 args.append("'");
469 this->command_line_ = args;
470 this->strtab_->add(this->command_line_.c_str(), false,
471 &this->command_line_key_);
474 // Record that the input argument INPUT is an achive ARCHIVE. This is
475 // called by Read_symbols after finding out the type of the file.
477 void
478 Incremental_inputs::report_archive(const Input_argument* input,
479 Archive* archive)
481 Hold_lock hl(*this->lock_);
483 Input_info info;
484 info.type = INCREMENTAL_INPUT_ARCHIVE;
485 info.archive = archive;
486 info.mtime = archive->file().get_mtime();
487 this->inputs_map_.insert(std::make_pair(input, info));
490 // Record that the input argument INPUT is an object OBJ. This is
491 // called by Read_symbols after finding out the type of the file.
493 void
494 Incremental_inputs::report_object(const Input_argument* input,
495 Object* obj)
497 Hold_lock hl(*this->lock_);
499 Input_info info;
500 info.type = (obj->is_dynamic()
501 ? INCREMENTAL_INPUT_SHARED_LIBRARY
502 : INCREMENTAL_INPUT_OBJECT);
503 info.object = obj;
504 info.mtime = obj->input_file()->file().get_mtime();
505 this->inputs_map_.insert(std::make_pair(input, info));
508 // Record that the input argument INPUT is an script SCRIPT. This is
509 // called by read_script after parsing the script and reading the list
510 // of inputs added by this script.
512 void
513 Incremental_inputs::report_script(const Input_argument* input,
514 Timespec mtime,
515 Script_info* script)
517 Hold_lock hl(*this->lock_);
519 Input_info info;
520 info.type = INCREMENTAL_INPUT_SCRIPT;
521 info.script = script;
522 info.mtime = mtime;
523 this->inputs_map_.insert(std::make_pair(input, info));
526 // Compute indexes in the order in which the inputs should appear in
527 // .gnu_incremental_inputs. This needs to be done after all the
528 // scripts are parsed. The function is first called for the command
529 // line inputs arguments and may call itself recursively for e.g. a
530 // list of elements of a group or a list of inputs added by a script.
531 // The [BEGIN; END) interval to analyze and *INDEX is the current
532 // value of the index (that will be updated).
534 void
535 Incremental_inputs::finalize_inputs(
536 Input_argument_list::const_iterator begin,
537 Input_argument_list::const_iterator end,
538 unsigned int* index)
540 for (Input_argument_list::const_iterator p = begin; p != end; ++p)
542 if (p->is_group())
544 finalize_inputs(p->group()->begin(), p->group()->end(), index);
545 continue;
548 Inputs_info_map::iterator it = this->inputs_map_.find(&(*p));
549 // TODO: turn it into an assert when the code will be more stable.
550 if (it == this->inputs_map_.end())
552 gold_error("internal error: %s: incremental build info not provided",
553 (p->is_file() ? p->file().name() : "[group]"));
554 continue;
556 Input_info* info = &it->second;
557 info->index = *index;
558 (*index)++;
559 this->strtab_->add(p->file().name(), false, &info->filename_key);
560 if (info->type == INCREMENTAL_INPUT_SCRIPT)
562 finalize_inputs(info->script->inputs()->begin(),
563 info->script->inputs()->end(),
564 index);
569 // Finalize the incremental link information. Called from
570 // Layout::finalize.
572 void
573 Incremental_inputs::finalize()
575 unsigned int index = 0;
576 finalize_inputs(this->inputs_->begin(), this->inputs_->end(), &index);
578 // Sanity check.
579 for (Inputs_info_map::const_iterator p = this->inputs_map_.begin();
580 p != this->inputs_map_.end();
581 ++p)
583 gold_assert(p->second.filename_key != 0);
586 this->strtab_->set_string_offsets();
589 // Create the content of the .gnu_incremental_inputs section.
591 Output_section_data*
592 Incremental_inputs::create_incremental_inputs_section_data()
594 switch (parameters->size_and_endianness())
596 #ifdef HAVE_TARGET_32_LITTLE
597 case Parameters::TARGET_32_LITTLE:
598 return this->sized_create_inputs_section_data<32, false>();
599 #endif
600 #ifdef HAVE_TARGET_32_BIG
601 case Parameters::TARGET_32_BIG:
602 return this->sized_create_inputs_section_data<32, true>();
603 #endif
604 #ifdef HAVE_TARGET_64_LITTLE
605 case Parameters::TARGET_64_LITTLE:
606 return this->sized_create_inputs_section_data<64, false>();
607 #endif
608 #ifdef HAVE_TARGET_64_BIG
609 case Parameters::TARGET_64_BIG:
610 return this->sized_create_inputs_section_data<64, true>();
611 #endif
612 default:
613 gold_unreachable();
617 // Sized creation of .gnu_incremental_inputs section.
619 template<int size, bool big_endian>
620 Output_section_data*
621 Incremental_inputs::sized_create_inputs_section_data()
623 const int entry_size =
624 Incremental_inputs_entry_write<size, big_endian>::data_size;
625 const int header_size =
626 Incremental_inputs_header_write<size, big_endian>::data_size;
628 unsigned int sz = header_size + entry_size * this->inputs_map_.size();
629 unsigned char* buffer = new unsigned char[sz];
630 unsigned char* inputs_base = buffer + header_size;
632 Incremental_inputs_header_write<size, big_endian> header_writer(buffer);
633 gold_assert(this->command_line_key_ > 0);
634 int cmd_offset = this->strtab_->get_offset_from_key(this->command_line_key_);
636 header_writer.put_version(INCREMENTAL_LINK_VERSION);
637 header_writer.put_input_file_count(this->inputs_map_.size());
638 header_writer.put_command_line_offset(cmd_offset);
639 header_writer.put_reserved(0);
641 for (Inputs_info_map::const_iterator it = this->inputs_map_.begin();
642 it != this->inputs_map_.end();
643 ++it)
645 gold_assert(it->second.index < this->inputs_map_.size());
647 unsigned char* entry_buffer =
648 inputs_base + it->second.index * entry_size;
649 Incremental_inputs_entry_write<size, big_endian> entry(entry_buffer);
650 int filename_offset =
651 this->strtab_->get_offset_from_key(it->second.filename_key);
652 entry.put_filename_offset(filename_offset);
653 switch (it->second.type)
655 case INCREMENTAL_INPUT_SCRIPT:
656 entry.put_data_offset(0);
657 break;
658 case INCREMENTAL_INPUT_ARCHIVE:
659 case INCREMENTAL_INPUT_OBJECT:
660 case INCREMENTAL_INPUT_SHARED_LIBRARY:
661 // TODO: add per input data. Currently we store
662 // an out-of-bounds offset for future version of gold to reject
663 // such an incremental_inputs section.
664 entry.put_data_offset(0xffffffff);
665 break;
666 default:
667 gold_unreachable();
669 // TODO: add per input data and timestamp. Currently we store
670 // an out-of-bounds offset for future version of gold to reject
671 // such an incremental_inputs section.
672 entry.put_data_offset(0xffffffff);
673 entry.put_timestamp_sec(it->second.mtime.seconds);
674 entry.put_timestamp_nsec(it->second.mtime.nanoseconds);
675 entry.put_input_type(it->second.type);
676 entry.put_reserved(0);
679 return new Output_data_const_buffer(buffer, sz, 8,
680 "** incremental link inputs list");
683 // Instantiate the templates we need.
685 #ifdef HAVE_TARGET_32_LITTLE
686 template
687 class Sized_incremental_binary<32, false>;
688 #endif
690 #ifdef HAVE_TARGET_32_BIG
691 template
692 class Sized_incremental_binary<32, true>;
693 #endif
695 #ifdef HAVE_TARGET_64_LITTLE
696 template
697 class Sized_incremental_binary<64, false>;
698 #endif
700 #ifdef HAVE_TARGET_64_BIG
701 template
702 class Sized_incremental_binary<64, true>;
703 #endif
705 } // End namespace gold.