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.
29 #include "incremental.h"
32 #include "target-select.h"
34 using elfcpp::Convert
;
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;
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
51 typedef Incremental_inputs_header_data Data_type
;
54 Incremental_inputs_header(const unsigned char *p
)
55 : p_(reinterpret_cast<const Data_type
*>(p
))
58 static const int data_size
= sizeof(Data_type
);
62 { return Convert
<32, big_endian
>::convert_host(this->p_
->version
); }
65 get_input_file_count() const
66 { return Convert
<32, big_endian
>::convert_host(this->p_
->input_file_count
); }
69 get_command_line_offset() const
70 { return Convert
<32, big_endian
>::convert_host(this->p_
->command_line_offset
); }
74 { return Convert
<32, big_endian
>::convert_host(this->p_
->reserved
); }
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
87 typedef Incremental_inputs_header_data Data_type
;
90 Incremental_inputs_header_write(unsigned char *p
)
91 : p_(reinterpret_cast<Data_type
*>(p
))
94 static const int data_size
= sizeof(Data_type
);
97 put_version(elfcpp::Elf_Word v
)
98 { this->p_
->version
= Convert
<32, big_endian
>::convert_host(v
); }
101 put_input_file_count(elfcpp::Elf_Word v
)
102 { this->p_
->input_file_count
= Convert
<32, big_endian
>::convert_host(v
); }
105 put_command_line_offset(elfcpp::Elf_Word v
)
106 { this->p_
->command_line_offset
= Convert
<32, big_endian
>::convert_host(v
); }
109 put_reserved(elfcpp::Elf_Word v
)
110 { this->p_
->reserved
= Convert
<32, big_endian
>::convert_host(v
); }
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
122 typedef Incremental_inputs_entry_data Data_type
;
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
);
132 get_filename_offset(elfcpp::Elf_Word v
)
133 { return Convert
<32, big_endian
>::convert_host(this->p_
->filename_offset
); }
136 get_data_offset(elfcpp::Elf_Word v
)
137 { return Convert
<32, big_endian
>::convert_host(this->p_
->data_offset
); }
140 get_timestamp_sec(elfcpp::Elf_Xword v
)
141 { return Convert
<64, big_endian
>::convert_host(this->p_
->timestamp_sec
); }
144 get_timestamp_nsec(elfcpp::Elf_Word v
)
145 { return Convert
<32, big_endian
>::convert_host(this->p_
->timestamp_nsec
); }
148 get_input_type(elfcpp::Elf_Word v
)
149 { return Convert
<32, big_endian
>::convert_host(this->p_
->input_type
); }
152 get_reserved(elfcpp::Elf_Word v
)
153 { return Convert
<32, big_endian
>::convert_host(this->p_
->reserved
); }
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
165 typedef Incremental_inputs_entry_data Data_type
;
168 Incremental_inputs_entry_write(unsigned char *p
)
169 : p_(reinterpret_cast<Data_type
*>(p
))
172 static const int data_size
= sizeof(Data_type
);
175 put_filename_offset(elfcpp::Elf_Word v
)
176 { this->p_
->filename_offset
= Convert
<32, big_endian
>::convert_host(v
); }
179 put_data_offset(elfcpp::Elf_Word v
)
180 { this->p_
->data_offset
= Convert
<32, big_endian
>::convert_host(v
); }
183 put_timestamp_sec(elfcpp::Elf_Xword v
)
184 { this->p_
->timestamp_sec
= Convert
<64, big_endian
>::convert_host(v
); }
187 put_timestamp_nsec(elfcpp::Elf_Word v
)
188 { this->p_
->timestamp_nsec
= Convert
<32, big_endian
>::convert_host(v
); }
191 put_input_type(elfcpp::Elf_Word v
)
192 { this->p_
->input_type
= Convert
<32, big_endian
>::convert_host(v
); }
195 put_reserved(elfcpp::Elf_Word v
)
196 { this->p_
->reserved
= Convert
<32, big_endian
>::convert_host(v
); }
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?
206 vexplain_no_incremental(const char* format
, va_list args
)
209 if (vasprintf(&buf
, format
, args
) < 0)
211 gold_info(_("the link might take longer: "
212 "cannot perform incremental link: %s"), buf
);
217 explain_no_incremental(const char* format
, ...)
220 va_start(args
, format
);
221 vexplain_no_incremental(format
, args
);
228 Incremental_binary::error(const char* format
, ...) const
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
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
);
241 template<int size
, bool big_endian
>
243 Sized_incremental_binary
<size
, big_endian
>::do_find_incremental_inputs_section(
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.
251 *strtab_shndx
= this->elf_file_
.section_link(shndx
);
252 *location
= this->elf_file_
.section_contents(shndx
);
256 template<int size
, bool big_endian
>
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
;
269 if (!do_find_incremental_inputs_section(&location
, &strtab_shndx
))
271 explain_no_incremental(_("no incremental data from previous build"));
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"));
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"));
294 const char* command_line
;
295 // We divide instead of multiplying to make sure there is no integer
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"));
305 if (incremental_inputs
->command_line() != command_line
)
307 explain_no_incremental(_("command line changed"));
311 // TODO: compare incremental_inputs->inputs() with entries in data_view.
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
>
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
]);
331 explain_no_incremental(_("unsupported ELF machine number %d"),
332 ehdr
.get_e_machine());
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
346 open_incremental_binary(Output_file
* file
)
348 off_t filesize
= file
->filesize();
349 int want
= elfcpp::Elf_recognizer::max_header_size
;
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."));
361 bool big_endian
= false;
363 if (!elfcpp::Elf_recognizer::is_valid_header(p
, want
, &size
, &big_endian
,
366 explain_no_incremental(error
.c_str());
370 Incremental_binary
* result
= NULL
;
375 #ifdef HAVE_TARGET_32_BIG
376 result
= make_sized_incremental_binary
<32, true>(
377 file
, elfcpp::Ehdr
<32, true>(p
));
379 explain_no_incremental(_("unsupported file: 32-bit, big-endian"));
384 #ifdef HAVE_TARGET_32_LITTLE
385 result
= make_sized_incremental_binary
<32, false>(
386 file
, elfcpp::Ehdr
<32, false>(p
));
388 explain_no_incremental(_("unsupported file: 32-bit, little-endian"));
396 #ifdef HAVE_TARGET_64_BIG
397 result
= make_sized_incremental_binary
<64, true>(
398 file
, elfcpp::Ehdr
<64, true>(p
));
400 explain_no_incremental(_("unsupported file: 64-bit, big-endian"));
405 #ifdef HAVE_TARGET_64_LITTLE
406 result
= make_sized_incremental_binary
<64, false>(
407 file
, elfcpp::Ehdr
<64, false>(p
));
409 explain_no_incremental(_("unsupported file: 64-bit, little-endian"));
419 // Analyzes the output file to check if incremental linking is possible and
420 // (to be done) what files need to be relinked.
423 Incremental_checker::can_incrementally_link_output_file()
425 Output_file
output(this->output_name_
);
426 if (!output
.open_for_modification())
428 Incremental_binary
* binary
= open_incremental_binary(&output
);
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.
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)
455 // Now append argv[i], but with all single-quotes escaped
456 const char* argpos
= argv
[i
];
459 const int len
= strcspn(argpos
, "'");
460 args
.append(argpos
, len
);
461 if (argpos
[len
] == '\0')
463 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.
478 Incremental_inputs::report_archive(const Input_argument
* input
,
481 Hold_lock
hl(*this->lock_
);
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.
494 Incremental_inputs::report_object(const Input_argument
* input
,
497 Hold_lock
hl(*this->lock_
);
500 info
.type
= (obj
->is_dynamic()
501 ? INCREMENTAL_INPUT_SHARED_LIBRARY
502 : INCREMENTAL_INPUT_OBJECT
);
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.
513 Incremental_inputs::report_script(const Input_argument
* input
,
517 Hold_lock
hl(*this->lock_
);
520 info
.type
= INCREMENTAL_INPUT_SCRIPT
;
521 info
.script
= script
;
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).
535 Incremental_inputs::finalize_inputs(
536 Input_argument_list::const_iterator begin
,
537 Input_argument_list::const_iterator end
,
540 for (Input_argument_list::const_iterator p
= begin
; p
!= end
; ++p
)
544 finalize_inputs(p
->group()->begin(), p
->group()->end(), index
);
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]"));
556 Input_info
* info
= &it
->second
;
557 info
->index
= *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(),
569 // Finalize the incremental link information. Called from
573 Incremental_inputs::finalize()
575 unsigned int index
= 0;
576 finalize_inputs(this->inputs_
->begin(), this->inputs_
->end(), &index
);
579 for (Inputs_info_map::const_iterator p
= this->inputs_map_
.begin();
580 p
!= this->inputs_map_
.end();
583 gold_assert(p
->second
.filename_key
!= 0);
586 this->strtab_
->set_string_offsets();
589 // Create the content of the .gnu_incremental_inputs section.
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>();
600 #ifdef HAVE_TARGET_32_BIG
601 case Parameters::TARGET_32_BIG
:
602 return this->sized_create_inputs_section_data
<32, true>();
604 #ifdef HAVE_TARGET_64_LITTLE
605 case Parameters::TARGET_64_LITTLE
:
606 return this->sized_create_inputs_section_data
<64, false>();
608 #ifdef HAVE_TARGET_64_BIG
609 case Parameters::TARGET_64_BIG
:
610 return this->sized_create_inputs_section_data
<64, true>();
617 // Sized creation of .gnu_incremental_inputs section.
619 template<int size
, bool big_endian
>
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();
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);
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);
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
687 class Sized_incremental_binary
<32, false>;
690 #ifdef HAVE_TARGET_32_BIG
692 class Sized_incremental_binary
<32, true>;
695 #ifdef HAVE_TARGET_64_LITTLE
697 class Sized_incremental_binary
<64, false>;
700 #ifdef HAVE_TARGET_64_BIG
702 class Sized_incremental_binary
<64, true>;
705 } // End namespace gold.