1 // layout.cc -- lay out output file sections for gold
3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012
4 // Free Software Foundation, Inc.
5 // Written by Ian Lance Taylor <iant@google.com>.
7 // This file is part of gold.
9 // This program is free software; you can redistribute it and/or modify
10 // it under the terms of the GNU General Public License as published by
11 // the Free Software Foundation; either version 3 of the License, or
12 // (at your option) any later version.
14 // This program is distributed in the hope that it will be useful,
15 // but WITHOUT ANY WARRANTY; without even the implied warranty of
16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 // GNU General Public License for more details.
19 // You should have received a copy of the GNU General Public License
20 // along with this program; if not, write to the Free Software
21 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
22 // MA 02110-1301, USA.
35 #include "libiberty.h"
39 #include "parameters.h"
43 #include "script-sections.h"
48 #include "gdb-index.h"
49 #include "compressed_output.h"
50 #include "reduced_debug_output.h"
53 #include "descriptors.h"
55 #include "incremental.h"
63 // The total number of free lists used.
64 unsigned int Free_list::num_lists
= 0;
65 // The total number of free list nodes used.
66 unsigned int Free_list::num_nodes
= 0;
67 // The total number of calls to Free_list::remove.
68 unsigned int Free_list::num_removes
= 0;
69 // The total number of nodes visited during calls to Free_list::remove.
70 unsigned int Free_list::num_remove_visits
= 0;
71 // The total number of calls to Free_list::allocate.
72 unsigned int Free_list::num_allocates
= 0;
73 // The total number of nodes visited during calls to Free_list::allocate.
74 unsigned int Free_list::num_allocate_visits
= 0;
76 // Initialize the free list. Creates a single free list node that
77 // describes the entire region of length LEN. If EXTEND is true,
78 // allocate() is allowed to extend the region beyond its initial
82 Free_list::init(off_t len
, bool extend
)
84 this->list_
.push_front(Free_list_node(0, len
));
85 this->last_remove_
= this->list_
.begin();
86 this->extend_
= extend
;
88 ++Free_list::num_lists
;
89 ++Free_list::num_nodes
;
92 // Remove a chunk from the free list. Because we start with a single
93 // node that covers the entire section, and remove chunks from it one
94 // at a time, we do not need to coalesce chunks or handle cases that
95 // span more than one free node. We expect to remove chunks from the
96 // free list in order, and we expect to have only a few chunks of free
97 // space left (corresponding to files that have changed since the last
98 // incremental link), so a simple linear list should provide sufficient
102 Free_list::remove(off_t start
, off_t end
)
106 gold_assert(start
< end
);
108 ++Free_list::num_removes
;
110 Iterator p
= this->last_remove_
;
111 if (p
->start_
> start
)
112 p
= this->list_
.begin();
114 for (; p
!= this->list_
.end(); ++p
)
116 ++Free_list::num_remove_visits
;
117 // Find a node that wholly contains the indicated region.
118 if (p
->start_
<= start
&& p
->end_
>= end
)
120 // Case 1: the indicated region spans the whole node.
121 // Add some fuzz to avoid creating tiny free chunks.
122 if (p
->start_
+ 3 >= start
&& p
->end_
<= end
+ 3)
123 p
= this->list_
.erase(p
);
124 // Case 2: remove a chunk from the start of the node.
125 else if (p
->start_
+ 3 >= start
)
127 // Case 3: remove a chunk from the end of the node.
128 else if (p
->end_
<= end
+ 3)
130 // Case 4: remove a chunk from the middle, and split
131 // the node into two.
134 Free_list_node
newnode(p
->start_
, start
);
136 this->list_
.insert(p
, newnode
);
137 ++Free_list::num_nodes
;
139 this->last_remove_
= p
;
144 // Did not find a node containing the given chunk. This could happen
145 // because a small chunk was already removed due to the fuzz.
146 gold_debug(DEBUG_INCREMENTAL
,
147 "Free_list::remove(%d,%d) not found",
148 static_cast<int>(start
), static_cast<int>(end
));
151 // Allocate a chunk of size LEN from the free list. Returns -1ULL
152 // if a sufficiently large chunk of free space is not found.
153 // We use a simple first-fit algorithm.
156 Free_list::allocate(off_t len
, uint64_t align
, off_t minoff
)
158 gold_debug(DEBUG_INCREMENTAL
,
159 "Free_list::allocate(%08lx, %d, %08lx)",
160 static_cast<long>(len
), static_cast<int>(align
),
161 static_cast<long>(minoff
));
163 return align_address(minoff
, align
);
165 ++Free_list::num_allocates
;
167 // We usually want to drop free chunks smaller than 4 bytes.
168 // If we need to guarantee a minimum hole size, though, we need
169 // to keep track of all free chunks.
170 const int fuzz
= this->min_hole_
> 0 ? 0 : 3;
172 for (Iterator p
= this->list_
.begin(); p
!= this->list_
.end(); ++p
)
174 ++Free_list::num_allocate_visits
;
175 off_t start
= p
->start_
> minoff
? p
->start_
: minoff
;
176 start
= align_address(start
, align
);
177 off_t end
= start
+ len
;
178 if (end
> p
->end_
&& p
->end_
== this->length_
&& this->extend_
)
183 if (end
== p
->end_
|| (end
<= p
->end_
- this->min_hole_
))
185 if (p
->start_
+ fuzz
>= start
&& p
->end_
<= end
+ fuzz
)
186 this->list_
.erase(p
);
187 else if (p
->start_
+ fuzz
>= start
)
189 else if (p
->end_
<= end
+ fuzz
)
193 Free_list_node
newnode(p
->start_
, start
);
195 this->list_
.insert(p
, newnode
);
196 ++Free_list::num_nodes
;
203 off_t start
= align_address(this->length_
, align
);
204 this->length_
= start
+ len
;
210 // Dump the free list (for debugging).
214 gold_info("Free list:\n start end length\n");
215 for (Iterator p
= this->list_
.begin(); p
!= this->list_
.end(); ++p
)
216 gold_info(" %08lx %08lx %08lx", static_cast<long>(p
->start_
),
217 static_cast<long>(p
->end_
),
218 static_cast<long>(p
->end_
- p
->start_
));
221 // Print the statistics for the free lists.
223 Free_list::print_stats()
225 fprintf(stderr
, _("%s: total free lists: %u\n"),
226 program_name
, Free_list::num_lists
);
227 fprintf(stderr
, _("%s: total free list nodes: %u\n"),
228 program_name
, Free_list::num_nodes
);
229 fprintf(stderr
, _("%s: calls to Free_list::remove: %u\n"),
230 program_name
, Free_list::num_removes
);
231 fprintf(stderr
, _("%s: nodes visited: %u\n"),
232 program_name
, Free_list::num_remove_visits
);
233 fprintf(stderr
, _("%s: calls to Free_list::allocate: %u\n"),
234 program_name
, Free_list::num_allocates
);
235 fprintf(stderr
, _("%s: nodes visited: %u\n"),
236 program_name
, Free_list::num_allocate_visits
);
239 // Layout::Relaxation_debug_check methods.
241 // Check that sections and special data are in reset states.
242 // We do not save states for Output_sections and special Output_data.
243 // So we check that they have not assigned any addresses or offsets.
244 // clean_up_after_relaxation simply resets their addresses and offsets.
246 Layout::Relaxation_debug_check::check_output_data_for_reset_values(
247 const Layout::Section_list
& sections
,
248 const Layout::Data_list
& special_outputs
)
250 for(Layout::Section_list::const_iterator p
= sections
.begin();
253 gold_assert((*p
)->address_and_file_offset_have_reset_values());
255 for(Layout::Data_list::const_iterator p
= special_outputs
.begin();
256 p
!= special_outputs
.end();
258 gold_assert((*p
)->address_and_file_offset_have_reset_values());
261 // Save information of SECTIONS for checking later.
264 Layout::Relaxation_debug_check::read_sections(
265 const Layout::Section_list
& sections
)
267 for(Layout::Section_list::const_iterator p
= sections
.begin();
271 Output_section
* os
= *p
;
273 info
.output_section
= os
;
274 info
.address
= os
->is_address_valid() ? os
->address() : 0;
275 info
.data_size
= os
->is_data_size_valid() ? os
->data_size() : -1;
276 info
.offset
= os
->is_offset_valid()? os
->offset() : -1 ;
277 this->section_infos_
.push_back(info
);
281 // Verify SECTIONS using previously recorded information.
284 Layout::Relaxation_debug_check::verify_sections(
285 const Layout::Section_list
& sections
)
288 for(Layout::Section_list::const_iterator p
= sections
.begin();
292 Output_section
* os
= *p
;
293 uint64_t address
= os
->is_address_valid() ? os
->address() : 0;
294 off_t data_size
= os
->is_data_size_valid() ? os
->data_size() : -1;
295 off_t offset
= os
->is_offset_valid()? os
->offset() : -1 ;
297 if (i
>= this->section_infos_
.size())
299 gold_fatal("Section_info of %s missing.\n", os
->name());
301 const Section_info
& info
= this->section_infos_
[i
];
302 if (os
!= info
.output_section
)
303 gold_fatal("Section order changed. Expecting %s but see %s\n",
304 info
.output_section
->name(), os
->name());
305 if (address
!= info
.address
306 || data_size
!= info
.data_size
307 || offset
!= info
.offset
)
308 gold_fatal("Section %s changed.\n", os
->name());
312 // Layout_task_runner methods.
314 // Lay out the sections. This is called after all the input objects
318 Layout_task_runner::run(Workqueue
* workqueue
, const Task
* task
)
320 Layout
* layout
= this->layout_
;
321 off_t file_size
= layout
->finalize(this->input_objects_
,
326 // Now we know the final size of the output file and we know where
327 // each piece of information goes.
329 if (this->mapfile_
!= NULL
)
331 this->mapfile_
->print_discarded_sections(this->input_objects_
);
332 layout
->print_to_mapfile(this->mapfile_
);
336 if (layout
->incremental_base() == NULL
)
338 of
= new Output_file(parameters
->options().output_file_name());
339 if (this->options_
.oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
340 of
->set_is_temporary();
345 of
= layout
->incremental_base()->output_file();
347 // Apply the incremental relocations for symbols whose values
348 // have changed. We do this before we resize the file and start
349 // writing anything else to it, so that we can read the old
350 // incremental information from the file before (possibly)
352 if (parameters
->incremental_update())
353 layout
->incremental_base()->apply_incremental_relocs(this->symtab_
,
357 of
->resize(file_size
);
360 // Queue up the final set of tasks.
361 gold::queue_final_tasks(this->options_
, this->input_objects_
,
362 this->symtab_
, layout
, workqueue
, of
);
367 Layout::Layout(int number_of_input_files
, Script_options
* script_options
)
368 : number_of_input_files_(number_of_input_files
),
369 script_options_(script_options
),
377 unattached_section_list_(),
378 special_output_list_(),
379 section_headers_(NULL
),
381 relro_segment_(NULL
),
382 interp_segment_(NULL
),
384 symtab_section_(NULL
),
385 symtab_xindex_(NULL
),
386 dynsym_section_(NULL
),
387 dynsym_xindex_(NULL
),
388 dynamic_section_(NULL
),
389 dynamic_symbol_(NULL
),
391 eh_frame_section_(NULL
),
392 eh_frame_data_(NULL
),
393 added_eh_frame_data_(false),
394 eh_frame_hdr_section_(NULL
),
395 gdb_index_data_(NULL
),
396 build_id_note_(NULL
),
400 output_file_size_(-1),
401 have_added_input_section_(false),
402 sections_are_attached_(false),
403 input_requires_executable_stack_(false),
404 input_with_gnu_stack_note_(false),
405 input_without_gnu_stack_note_(false),
406 has_static_tls_(false),
407 any_postprocessing_sections_(false),
408 resized_signatures_(false),
409 have_stabstr_section_(false),
410 section_ordering_specified_(false),
411 unique_segment_for_sections_specified_(false),
412 incremental_inputs_(NULL
),
413 record_output_section_data_from_script_(false),
414 script_output_section_data_list_(),
415 segment_states_(NULL
),
416 relaxation_debug_check_(NULL
),
417 section_order_map_(),
418 section_segment_map_(),
419 input_section_position_(),
420 input_section_glob_(),
421 incremental_base_(NULL
),
424 // Make space for more than enough segments for a typical file.
425 // This is just for efficiency--it's OK if we wind up needing more.
426 this->segment_list_
.reserve(12);
428 // We expect two unattached Output_data objects: the file header and
429 // the segment headers.
430 this->special_output_list_
.reserve(2);
432 // Initialize structure needed for an incremental build.
433 if (parameters
->incremental())
434 this->incremental_inputs_
= new Incremental_inputs
;
436 // The section name pool is worth optimizing in all cases, because
437 // it is small, but there are often overlaps due to .rel sections.
438 this->namepool_
.set_optimize();
441 // For incremental links, record the base file to be modified.
444 Layout::set_incremental_base(Incremental_binary
* base
)
446 this->incremental_base_
= base
;
447 this->free_list_
.init(base
->output_file()->filesize(), true);
450 // Hash a key we use to look up an output section mapping.
453 Layout::Hash_key::operator()(const Layout::Key
& k
) const
455 return k
.first
+ k
.second
.first
+ k
.second
.second
;
458 // These are the debug sections that are actually used by gdb.
459 // Currently, we've checked versions of gdb up to and including 7.4.
460 // We only check the part of the name that follows ".debug_" or
463 static const char* gdb_sections
[] =
466 "addr", // Fission extension
467 // "aranges", // not used by gdb as of 7.4
475 // "pubnames", // not used by gdb as of 7.4
476 // "pubtypes", // not used by gdb as of 7.4
481 // This is the minimum set of sections needed for line numbers.
483 static const char* lines_only_debug_sections
[] =
486 // "addr", // Fission extension
487 // "aranges", // not used by gdb as of 7.4
495 // "pubnames", // not used by gdb as of 7.4
496 // "pubtypes", // not used by gdb as of 7.4
501 // These sections are the DWARF fast-lookup tables, and are not needed
502 // when building a .gdb_index section.
504 static const char* gdb_fast_lookup_sections
[] =
511 // Returns whether the given debug section is in the list of
512 // debug-sections-used-by-some-version-of-gdb. SUFFIX is the
513 // portion of the name following ".debug_" or ".zdebug_".
516 is_gdb_debug_section(const char* suffix
)
518 // We can do this faster: binary search or a hashtable. But why bother?
519 for (size_t i
= 0; i
< sizeof(gdb_sections
)/sizeof(*gdb_sections
); ++i
)
520 if (strcmp(suffix
, gdb_sections
[i
]) == 0)
525 // Returns whether the given section is needed for lines-only debugging.
528 is_lines_only_debug_section(const char* suffix
)
530 // We can do this faster: binary search or a hashtable. But why bother?
532 i
< sizeof(lines_only_debug_sections
)/sizeof(*lines_only_debug_sections
);
534 if (strcmp(suffix
, lines_only_debug_sections
[i
]) == 0)
539 // Returns whether the given section is a fast-lookup section that
540 // will not be needed when building a .gdb_index section.
543 is_gdb_fast_lookup_section(const char* suffix
)
545 // We can do this faster: binary search or a hashtable. But why bother?
547 i
< sizeof(gdb_fast_lookup_sections
)/sizeof(*gdb_fast_lookup_sections
);
549 if (strcmp(suffix
, gdb_fast_lookup_sections
[i
]) == 0)
554 // Sometimes we compress sections. This is typically done for
555 // sections that are not part of normal program execution (such as
556 // .debug_* sections), and where the readers of these sections know
557 // how to deal with compressed sections. This routine doesn't say for
558 // certain whether we'll compress -- it depends on commandline options
559 // as well -- just whether this section is a candidate for compression.
560 // (The Output_compressed_section class decides whether to compress
561 // a given section, and picks the name of the compressed section.)
564 is_compressible_debug_section(const char* secname
)
566 return (is_prefix_of(".debug", secname
));
569 // We may see compressed debug sections in input files. Return TRUE
570 // if this is the name of a compressed debug section.
573 is_compressed_debug_section(const char* secname
)
575 return (is_prefix_of(".zdebug", secname
));
578 // Whether to include this section in the link.
580 template<int size
, bool big_endian
>
582 Layout::include_section(Sized_relobj_file
<size
, big_endian
>*, const char* name
,
583 const elfcpp::Shdr
<size
, big_endian
>& shdr
)
585 if (!parameters
->options().relocatable()
586 && (shdr
.get_sh_flags() & elfcpp::SHF_EXCLUDE
))
589 switch (shdr
.get_sh_type())
591 case elfcpp::SHT_NULL
:
592 case elfcpp::SHT_SYMTAB
:
593 case elfcpp::SHT_DYNSYM
:
594 case elfcpp::SHT_HASH
:
595 case elfcpp::SHT_DYNAMIC
:
596 case elfcpp::SHT_SYMTAB_SHNDX
:
599 case elfcpp::SHT_STRTAB
:
600 // Discard the sections which have special meanings in the ELF
601 // ABI. Keep others (e.g., .stabstr). We could also do this by
602 // checking the sh_link fields of the appropriate sections.
603 return (strcmp(name
, ".dynstr") != 0
604 && strcmp(name
, ".strtab") != 0
605 && strcmp(name
, ".shstrtab") != 0);
607 case elfcpp::SHT_RELA
:
608 case elfcpp::SHT_REL
:
609 case elfcpp::SHT_GROUP
:
610 // If we are emitting relocations these should be handled
612 gold_assert(!parameters
->options().relocatable());
615 case elfcpp::SHT_PROGBITS
:
616 if (parameters
->options().strip_debug()
617 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
619 if (is_debug_info_section(name
))
622 if (parameters
->options().strip_debug_non_line()
623 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
625 // Debugging sections can only be recognized by name.
626 if (is_prefix_of(".debug_", name
)
627 && !is_lines_only_debug_section(name
+ 7))
629 if (is_prefix_of(".zdebug_", name
)
630 && !is_lines_only_debug_section(name
+ 8))
633 if (parameters
->options().strip_debug_gdb()
634 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
636 // Debugging sections can only be recognized by name.
637 if (is_prefix_of(".debug_", name
)
638 && !is_gdb_debug_section(name
+ 7))
640 if (is_prefix_of(".zdebug_", name
)
641 && !is_gdb_debug_section(name
+ 8))
644 if (parameters
->options().gdb_index()
645 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
647 // When building .gdb_index, we can strip .debug_pubnames,
648 // .debug_pubtypes, and .debug_aranges sections.
649 if (is_prefix_of(".debug_", name
)
650 && is_gdb_fast_lookup_section(name
+ 7))
652 if (is_prefix_of(".zdebug_", name
)
653 && is_gdb_fast_lookup_section(name
+ 8))
656 if (parameters
->options().strip_lto_sections()
657 && !parameters
->options().relocatable()
658 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
660 // Ignore LTO sections containing intermediate code.
661 if (is_prefix_of(".gnu.lto_", name
))
664 // The GNU linker strips .gnu_debuglink sections, so we do too.
665 // This is a feature used to keep debugging information in
667 if (strcmp(name
, ".gnu_debuglink") == 0)
676 // Return an output section named NAME, or NULL if there is none.
679 Layout::find_output_section(const char* name
) const
681 for (Section_list::const_iterator p
= this->section_list_
.begin();
682 p
!= this->section_list_
.end();
684 if (strcmp((*p
)->name(), name
) == 0)
689 // Return an output segment of type TYPE, with segment flags SET set
690 // and segment flags CLEAR clear. Return NULL if there is none.
693 Layout::find_output_segment(elfcpp::PT type
, elfcpp::Elf_Word set
,
694 elfcpp::Elf_Word clear
) const
696 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
697 p
!= this->segment_list_
.end();
699 if (static_cast<elfcpp::PT
>((*p
)->type()) == type
700 && ((*p
)->flags() & set
) == set
701 && ((*p
)->flags() & clear
) == 0)
706 // When we put a .ctors or .dtors section with more than one word into
707 // a .init_array or .fini_array section, we need to reverse the words
708 // in the .ctors/.dtors section. This is because .init_array executes
709 // constructors front to back, where .ctors executes them back to
710 // front, and vice-versa for .fini_array/.dtors. Although we do want
711 // to remap .ctors/.dtors into .init_array/.fini_array because it can
712 // be more efficient, we don't want to change the order in which
713 // constructors/destructors are run. This set just keeps track of
714 // these sections which need to be reversed. It is only changed by
715 // Layout::layout. It should be a private member of Layout, but that
716 // would require layout.h to #include object.h to get the definition
718 static Unordered_set
<Section_id
, Section_id_hash
> ctors_sections_in_init_array
;
720 // Return whether OBJECT/SHNDX is a .ctors/.dtors section mapped to a
721 // .init_array/.fini_array section.
724 Layout::is_ctors_in_init_array(Relobj
* relobj
, unsigned int shndx
) const
726 return (ctors_sections_in_init_array
.find(Section_id(relobj
, shndx
))
727 != ctors_sections_in_init_array
.end());
730 // Return the output section to use for section NAME with type TYPE
731 // and section flags FLAGS. NAME must be canonicalized in the string
732 // pool, and NAME_KEY is the key. ORDER is where this should appear
733 // in the output sections. IS_RELRO is true for a relro section.
736 Layout::get_output_section(const char* name
, Stringpool::Key name_key
,
737 elfcpp::Elf_Word type
, elfcpp::Elf_Xword flags
,
738 Output_section_order order
, bool is_relro
)
740 elfcpp::Elf_Word lookup_type
= type
;
742 // For lookup purposes, treat INIT_ARRAY, FINI_ARRAY, and
743 // PREINIT_ARRAY like PROGBITS. This ensures that we combine
744 // .init_array, .fini_array, and .preinit_array sections by name
745 // whatever their type in the input file. We do this because the
746 // types are not always right in the input files.
747 if (lookup_type
== elfcpp::SHT_INIT_ARRAY
748 || lookup_type
== elfcpp::SHT_FINI_ARRAY
749 || lookup_type
== elfcpp::SHT_PREINIT_ARRAY
)
750 lookup_type
= elfcpp::SHT_PROGBITS
;
752 elfcpp::Elf_Xword lookup_flags
= flags
;
754 // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
755 // read-write with read-only sections. Some other ELF linkers do
756 // not do this. FIXME: Perhaps there should be an option
758 lookup_flags
&= ~(elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
760 const Key
key(name_key
, std::make_pair(lookup_type
, lookup_flags
));
761 const std::pair
<Key
, Output_section
*> v(key
, NULL
);
762 std::pair
<Section_name_map::iterator
, bool> ins(
763 this->section_name_map_
.insert(v
));
766 return ins
.first
->second
;
769 // This is the first time we've seen this name/type/flags
770 // combination. For compatibility with the GNU linker, we
771 // combine sections with contents and zero flags with sections
772 // with non-zero flags. This is a workaround for cases where
773 // assembler code forgets to set section flags. FIXME: Perhaps
774 // there should be an option to control this.
775 Output_section
* os
= NULL
;
777 if (lookup_type
== elfcpp::SHT_PROGBITS
)
781 Output_section
* same_name
= this->find_output_section(name
);
782 if (same_name
!= NULL
783 && (same_name
->type() == elfcpp::SHT_PROGBITS
784 || same_name
->type() == elfcpp::SHT_INIT_ARRAY
785 || same_name
->type() == elfcpp::SHT_FINI_ARRAY
786 || same_name
->type() == elfcpp::SHT_PREINIT_ARRAY
)
787 && (same_name
->flags() & elfcpp::SHF_TLS
) == 0)
790 else if ((flags
& elfcpp::SHF_TLS
) == 0)
792 elfcpp::Elf_Xword zero_flags
= 0;
793 const Key
zero_key(name_key
, std::make_pair(lookup_type
,
795 Section_name_map::iterator p
=
796 this->section_name_map_
.find(zero_key
);
797 if (p
!= this->section_name_map_
.end())
803 os
= this->make_output_section(name
, type
, flags
, order
, is_relro
);
805 ins
.first
->second
= os
;
810 // Returns TRUE iff NAME (an input section from RELOBJ) will
811 // be mapped to an output section that should be KEPT.
814 Layout::keep_input_section(const Relobj
* relobj
, const char* name
)
816 if (! this->script_options_
->saw_sections_clause())
819 Script_sections
* ss
= this->script_options_
->script_sections();
820 const char* file_name
= relobj
== NULL
? NULL
: relobj
->name().c_str();
821 Output_section
** output_section_slot
;
822 Script_sections::Section_type script_section_type
;
825 name
= ss
->output_section_name(file_name
, name
, &output_section_slot
,
826 &script_section_type
, &keep
);
827 return name
!= NULL
&& keep
;
830 // Clear the input section flags that should not be copied to the
834 Layout::get_output_section_flags(elfcpp::Elf_Xword input_section_flags
)
836 // Some flags in the input section should not be automatically
837 // copied to the output section.
838 input_section_flags
&= ~ (elfcpp::SHF_INFO_LINK
841 | elfcpp::SHF_STRINGS
);
843 // We only clear the SHF_LINK_ORDER flag in for
844 // a non-relocatable link.
845 if (!parameters
->options().relocatable())
846 input_section_flags
&= ~elfcpp::SHF_LINK_ORDER
;
848 return input_section_flags
;
851 // Pick the output section to use for section NAME, in input file
852 // RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a
853 // linker created section. IS_INPUT_SECTION is true if we are
854 // choosing an output section for an input section found in a input
855 // file. ORDER is where this section should appear in the output
856 // sections. IS_RELRO is true for a relro section. This will return
857 // NULL if the input section should be discarded.
860 Layout::choose_output_section(const Relobj
* relobj
, const char* name
,
861 elfcpp::Elf_Word type
, elfcpp::Elf_Xword flags
,
862 bool is_input_section
, Output_section_order order
,
865 // We should not see any input sections after we have attached
866 // sections to segments.
867 gold_assert(!is_input_section
|| !this->sections_are_attached_
);
869 flags
= this->get_output_section_flags(flags
);
871 if (this->script_options_
->saw_sections_clause())
873 // We are using a SECTIONS clause, so the output section is
874 // chosen based only on the name.
876 Script_sections
* ss
= this->script_options_
->script_sections();
877 const char* file_name
= relobj
== NULL
? NULL
: relobj
->name().c_str();
878 Output_section
** output_section_slot
;
879 Script_sections::Section_type script_section_type
;
880 const char* orig_name
= name
;
882 name
= ss
->output_section_name(file_name
, name
, &output_section_slot
,
883 &script_section_type
, &keep
);
887 gold_debug(DEBUG_SCRIPT
, _("Unable to create output section '%s' "
888 "because it is not allowed by the "
889 "SECTIONS clause of the linker script"),
891 // The SECTIONS clause says to discard this input section.
895 // We can only handle script section types ST_NONE and ST_NOLOAD.
896 switch (script_section_type
)
898 case Script_sections::ST_NONE
:
900 case Script_sections::ST_NOLOAD
:
901 flags
&= elfcpp::SHF_ALLOC
;
907 // If this is an orphan section--one not mentioned in the linker
908 // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
909 // default processing below.
911 if (output_section_slot
!= NULL
)
913 if (*output_section_slot
!= NULL
)
915 (*output_section_slot
)->update_flags_for_input_section(flags
);
916 return *output_section_slot
;
919 // We don't put sections found in the linker script into
920 // SECTION_NAME_MAP_. That keeps us from getting confused
921 // if an orphan section is mapped to a section with the same
922 // name as one in the linker script.
924 name
= this->namepool_
.add(name
, false, NULL
);
926 Output_section
* os
= this->make_output_section(name
, type
, flags
,
929 os
->set_found_in_sections_clause();
931 // Special handling for NOLOAD sections.
932 if (script_section_type
== Script_sections::ST_NOLOAD
)
936 // The constructor of Output_section sets addresses of non-ALLOC
937 // sections to 0 by default. We don't want that for NOLOAD
938 // sections even if they have no SHF_ALLOC flag.
939 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0
940 && os
->is_address_valid())
942 gold_assert(os
->address() == 0
943 && !os
->is_offset_valid()
944 && !os
->is_data_size_valid());
945 os
->reset_address_and_file_offset();
949 *output_section_slot
= os
;
954 // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
956 size_t len
= strlen(name
);
957 char* uncompressed_name
= NULL
;
959 // Compressed debug sections should be mapped to the corresponding
960 // uncompressed section.
961 if (is_compressed_debug_section(name
))
963 uncompressed_name
= new char[len
];
964 uncompressed_name
[0] = '.';
965 gold_assert(name
[0] == '.' && name
[1] == 'z');
966 strncpy(&uncompressed_name
[1], &name
[2], len
- 2);
967 uncompressed_name
[len
- 1] = '\0';
969 name
= uncompressed_name
;
972 // Turn NAME from the name of the input section into the name of the
975 && !this->script_options_
->saw_sections_clause()
976 && !parameters
->options().relocatable())
978 const char *orig_name
= name
;
979 name
= parameters
->target().output_section_name(relobj
, name
, &len
);
981 name
= Layout::output_section_name(relobj
, orig_name
, &len
);
984 Stringpool::Key name_key
;
985 name
= this->namepool_
.add_with_length(name
, len
, true, &name_key
);
987 if (uncompressed_name
!= NULL
)
988 delete[] uncompressed_name
;
990 // Find or make the output section. The output section is selected
991 // based on the section name, type, and flags.
992 return this->get_output_section(name
, name_key
, type
, flags
, order
, is_relro
);
995 // For incremental links, record the initial fixed layout of a section
996 // from the base file, and return a pointer to the Output_section.
998 template<int size
, bool big_endian
>
1000 Layout::init_fixed_output_section(const char* name
,
1001 elfcpp::Shdr
<size
, big_endian
>& shdr
)
1003 unsigned int sh_type
= shdr
.get_sh_type();
1005 // We preserve the layout of PROGBITS, NOBITS, INIT_ARRAY, FINI_ARRAY,
1006 // PRE_INIT_ARRAY, and NOTE sections.
1007 // All others will be created from scratch and reallocated.
1008 if (!can_incremental_update(sh_type
))
1011 // If we're generating a .gdb_index section, we need to regenerate
1013 if (parameters
->options().gdb_index()
1014 && sh_type
== elfcpp::SHT_PROGBITS
1015 && strcmp(name
, ".gdb_index") == 0)
1018 typename
elfcpp::Elf_types
<size
>::Elf_Addr sh_addr
= shdr
.get_sh_addr();
1019 typename
elfcpp::Elf_types
<size
>::Elf_Off sh_offset
= shdr
.get_sh_offset();
1020 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_size
= shdr
.get_sh_size();
1021 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_flags
= shdr
.get_sh_flags();
1022 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_addralign
=
1023 shdr
.get_sh_addralign();
1025 // Make the output section.
1026 Stringpool::Key name_key
;
1027 name
= this->namepool_
.add(name
, true, &name_key
);
1028 Output_section
* os
= this->get_output_section(name
, name_key
, sh_type
,
1029 sh_flags
, ORDER_INVALID
, false);
1030 os
->set_fixed_layout(sh_addr
, sh_offset
, sh_size
, sh_addralign
);
1031 if (sh_type
!= elfcpp::SHT_NOBITS
)
1032 this->free_list_
.remove(sh_offset
, sh_offset
+ sh_size
);
1036 // Return the index by which an input section should be ordered. This
1037 // is used to sort some .text sections, for compatibility with GNU ld.
1040 Layout::special_ordering_of_input_section(const char* name
)
1042 // The GNU linker has some special handling for some sections that
1043 // wind up in the .text section. Sections that start with these
1044 // prefixes must appear first, and must appear in the order listed
1046 static const char* const text_section_sort
[] =
1055 i
< sizeof(text_section_sort
) / sizeof(text_section_sort
[0]);
1057 if (is_prefix_of(text_section_sort
[i
], name
))
1063 // Return the output section to use for input section SHNDX, with name
1064 // NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the
1065 // index of a relocation section which applies to this section, or 0
1066 // if none, or -1U if more than one. RELOC_TYPE is the type of the
1067 // relocation section if there is one. Set *OFF to the offset of this
1068 // input section without the output section. Return NULL if the
1069 // section should be discarded. Set *OFF to -1 if the section
1070 // contents should not be written directly to the output file, but
1071 // will instead receive special handling.
1073 template<int size
, bool big_endian
>
1075 Layout::layout(Sized_relobj_file
<size
, big_endian
>* object
, unsigned int shndx
,
1076 const char* name
, const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1077 unsigned int reloc_shndx
, unsigned int, off_t
* off
)
1081 if (!this->include_section(object
, name
, shdr
))
1084 elfcpp::Elf_Word sh_type
= shdr
.get_sh_type();
1086 // In a relocatable link a grouped section must not be combined with
1087 // any other sections.
1089 if (parameters
->options().relocatable()
1090 && (shdr
.get_sh_flags() & elfcpp::SHF_GROUP
) != 0)
1092 name
= this->namepool_
.add(name
, true, NULL
);
1093 os
= this->make_output_section(name
, sh_type
, shdr
.get_sh_flags(),
1094 ORDER_INVALID
, false);
1098 // Plugins can choose to place one or more subsets of sections in
1099 // unique segments and this is done by mapping these section subsets
1100 // to unique output sections. Check if this section needs to be
1101 // remapped to a unique output section.
1102 Section_segment_map::iterator it
1103 = this->section_segment_map_
.find(Const_section_id(object
, shndx
));
1104 if (it
== this->section_segment_map_
.end())
1106 os
= this->choose_output_section(object
, name
, sh_type
,
1107 shdr
.get_sh_flags(), true,
1108 ORDER_INVALID
, false);
1112 // We know the name of the output section, directly call
1113 // get_output_section here by-passing choose_output_section.
1114 elfcpp::Elf_Xword flags
1115 = this->get_output_section_flags(shdr
.get_sh_flags());
1117 const char* os_name
= it
->second
->name
;
1118 Stringpool::Key name_key
;
1119 os_name
= this->namepool_
.add(os_name
, true, &name_key
);
1120 os
= this->get_output_section(os_name
, name_key
, sh_type
, flags
,
1121 ORDER_INVALID
, false);
1122 if (!os
->is_unique_segment())
1124 os
->set_is_unique_segment();
1125 os
->set_extra_segment_flags(it
->second
->flags
);
1126 os
->set_segment_alignment(it
->second
->align
);
1133 // By default the GNU linker sorts input sections whose names match
1134 // .ctors.*, .dtors.*, .init_array.*, or .fini_array.*. The
1135 // sections are sorted by name. This is used to implement
1136 // constructor priority ordering. We are compatible. When we put
1137 // .ctor sections in .init_array and .dtor sections in .fini_array,
1138 // we must also sort plain .ctor and .dtor sections.
1139 if (!this->script_options_
->saw_sections_clause()
1140 && !parameters
->options().relocatable()
1141 && (is_prefix_of(".ctors.", name
)
1142 || is_prefix_of(".dtors.", name
)
1143 || is_prefix_of(".init_array.", name
)
1144 || is_prefix_of(".fini_array.", name
)
1145 || (parameters
->options().ctors_in_init_array()
1146 && (strcmp(name
, ".ctors") == 0
1147 || strcmp(name
, ".dtors") == 0))))
1148 os
->set_must_sort_attached_input_sections();
1150 // By default the GNU linker sorts some special text sections ahead
1151 // of others. We are compatible.
1152 if (!this->script_options_
->saw_sections_clause()
1153 && !this->is_section_ordering_specified()
1154 && !parameters
->options().relocatable()
1155 && Layout::special_ordering_of_input_section(name
) >= 0)
1156 os
->set_must_sort_attached_input_sections();
1158 // If this is a .ctors or .ctors.* section being mapped to a
1159 // .init_array section, or a .dtors or .dtors.* section being mapped
1160 // to a .fini_array section, we will need to reverse the words if
1161 // there is more than one. Record this section for later. See
1162 // ctors_sections_in_init_array above.
1163 if (!this->script_options_
->saw_sections_clause()
1164 && !parameters
->options().relocatable()
1165 && shdr
.get_sh_size() > size
/ 8
1166 && (((strcmp(name
, ".ctors") == 0
1167 || is_prefix_of(".ctors.", name
))
1168 && strcmp(os
->name(), ".init_array") == 0)
1169 || ((strcmp(name
, ".dtors") == 0
1170 || is_prefix_of(".dtors.", name
))
1171 && strcmp(os
->name(), ".fini_array") == 0)))
1172 ctors_sections_in_init_array
.insert(Section_id(object
, shndx
));
1174 // FIXME: Handle SHF_LINK_ORDER somewhere.
1176 elfcpp::Elf_Xword orig_flags
= os
->flags();
1178 *off
= os
->add_input_section(this, object
, shndx
, name
, shdr
, reloc_shndx
,
1179 this->script_options_
->saw_sections_clause());
1181 // If the flags changed, we may have to change the order.
1182 if ((orig_flags
& elfcpp::SHF_ALLOC
) != 0)
1184 orig_flags
&= (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
1185 elfcpp::Elf_Xword new_flags
=
1186 os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
1187 if (orig_flags
!= new_flags
)
1188 os
->set_order(this->default_section_order(os
, false));
1191 this->have_added_input_section_
= true;
1196 // Maps section SECN to SEGMENT s.
1198 Layout::insert_section_segment_map(Const_section_id secn
,
1199 Unique_segment_info
*s
)
1201 gold_assert(this->unique_segment_for_sections_specified_
);
1202 this->section_segment_map_
[secn
] = s
;
1205 // Handle a relocation section when doing a relocatable link.
1207 template<int size
, bool big_endian
>
1209 Layout::layout_reloc(Sized_relobj_file
<size
, big_endian
>* object
,
1211 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1212 Output_section
* data_section
,
1213 Relocatable_relocs
* rr
)
1215 gold_assert(parameters
->options().relocatable()
1216 || parameters
->options().emit_relocs());
1218 int sh_type
= shdr
.get_sh_type();
1221 if (sh_type
== elfcpp::SHT_REL
)
1223 else if (sh_type
== elfcpp::SHT_RELA
)
1227 name
+= data_section
->name();
1229 // In a relocatable link relocs for a grouped section must not be
1230 // combined with other reloc sections.
1232 if (!parameters
->options().relocatable()
1233 || (data_section
->flags() & elfcpp::SHF_GROUP
) == 0)
1234 os
= this->choose_output_section(object
, name
.c_str(), sh_type
,
1235 shdr
.get_sh_flags(), false,
1236 ORDER_INVALID
, false);
1239 const char* n
= this->namepool_
.add(name
.c_str(), true, NULL
);
1240 os
= this->make_output_section(n
, sh_type
, shdr
.get_sh_flags(),
1241 ORDER_INVALID
, false);
1244 os
->set_should_link_to_symtab();
1245 os
->set_info_section(data_section
);
1247 Output_section_data
* posd
;
1248 if (sh_type
== elfcpp::SHT_REL
)
1250 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rel_size
);
1251 posd
= new Output_relocatable_relocs
<elfcpp::SHT_REL
,
1255 else if (sh_type
== elfcpp::SHT_RELA
)
1257 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rela_size
);
1258 posd
= new Output_relocatable_relocs
<elfcpp::SHT_RELA
,
1265 os
->add_output_section_data(posd
);
1266 rr
->set_output_data(posd
);
1271 // Handle a group section when doing a relocatable link.
1273 template<int size
, bool big_endian
>
1275 Layout::layout_group(Symbol_table
* symtab
,
1276 Sized_relobj_file
<size
, big_endian
>* object
,
1278 const char* group_section_name
,
1279 const char* signature
,
1280 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1281 elfcpp::Elf_Word flags
,
1282 std::vector
<unsigned int>* shndxes
)
1284 gold_assert(parameters
->options().relocatable());
1285 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_GROUP
);
1286 group_section_name
= this->namepool_
.add(group_section_name
, true, NULL
);
1287 Output_section
* os
= this->make_output_section(group_section_name
,
1289 shdr
.get_sh_flags(),
1290 ORDER_INVALID
, false);
1292 // We need to find a symbol with the signature in the symbol table.
1293 // If we don't find one now, we need to look again later.
1294 Symbol
* sym
= symtab
->lookup(signature
, NULL
);
1296 os
->set_info_symndx(sym
);
1299 // Reserve some space to minimize reallocations.
1300 if (this->group_signatures_
.empty())
1301 this->group_signatures_
.reserve(this->number_of_input_files_
* 16);
1303 // We will wind up using a symbol whose name is the signature.
1304 // So just put the signature in the symbol name pool to save it.
1305 signature
= symtab
->canonicalize_name(signature
);
1306 this->group_signatures_
.push_back(Group_signature(os
, signature
));
1309 os
->set_should_link_to_symtab();
1312 section_size_type entry_count
=
1313 convert_to_section_size_type(shdr
.get_sh_size() / 4);
1314 Output_section_data
* posd
=
1315 new Output_data_group
<size
, big_endian
>(object
, entry_count
, flags
,
1317 os
->add_output_section_data(posd
);
1320 // Special GNU handling of sections name .eh_frame. They will
1321 // normally hold exception frame data as defined by the C++ ABI
1322 // (http://codesourcery.com/cxx-abi/).
1324 template<int size
, bool big_endian
>
1326 Layout::layout_eh_frame(Sized_relobj_file
<size
, big_endian
>* object
,
1327 const unsigned char* symbols
,
1329 const unsigned char* symbol_names
,
1330 off_t symbol_names_size
,
1332 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1333 unsigned int reloc_shndx
, unsigned int reloc_type
,
1336 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_PROGBITS
1337 || shdr
.get_sh_type() == elfcpp::SHT_X86_64_UNWIND
);
1338 gold_assert((shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) != 0);
1340 Output_section
* os
= this->make_eh_frame_section(object
);
1344 gold_assert(this->eh_frame_section_
== os
);
1346 elfcpp::Elf_Xword orig_flags
= os
->flags();
1348 if (!parameters
->incremental()
1349 && this->eh_frame_data_
->add_ehframe_input_section(object
,
1358 os
->update_flags_for_input_section(shdr
.get_sh_flags());
1360 // A writable .eh_frame section is a RELRO section.
1361 if ((orig_flags
& (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
))
1362 != (os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
)))
1365 os
->set_order(ORDER_RELRO
);
1368 // We found a .eh_frame section we are going to optimize, so now
1369 // we can add the set of optimized sections to the output
1370 // section. We need to postpone adding this until we've found a
1371 // section we can optimize so that the .eh_frame section in
1372 // crtbegin.o winds up at the start of the output section.
1373 if (!this->added_eh_frame_data_
)
1375 os
->add_output_section_data(this->eh_frame_data_
);
1376 this->added_eh_frame_data_
= true;
1382 // We couldn't handle this .eh_frame section for some reason.
1383 // Add it as a normal section.
1384 bool saw_sections_clause
= this->script_options_
->saw_sections_clause();
1385 *off
= os
->add_input_section(this, object
, shndx
, ".eh_frame", shdr
,
1386 reloc_shndx
, saw_sections_clause
);
1387 this->have_added_input_section_
= true;
1389 if ((orig_flags
& (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
))
1390 != (os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
)))
1391 os
->set_order(this->default_section_order(os
, false));
1397 // Create and return the magic .eh_frame section. Create
1398 // .eh_frame_hdr also if appropriate. OBJECT is the object with the
1399 // input .eh_frame section; it may be NULL.
1402 Layout::make_eh_frame_section(const Relobj
* object
)
1404 // FIXME: On x86_64, this could use SHT_X86_64_UNWIND rather than
1406 Output_section
* os
= this->choose_output_section(object
, ".eh_frame",
1407 elfcpp::SHT_PROGBITS
,
1408 elfcpp::SHF_ALLOC
, false,
1409 ORDER_EHFRAME
, false);
1413 if (this->eh_frame_section_
== NULL
)
1415 this->eh_frame_section_
= os
;
1416 this->eh_frame_data_
= new Eh_frame();
1418 // For incremental linking, we do not optimize .eh_frame sections
1419 // or create a .eh_frame_hdr section.
1420 if (parameters
->options().eh_frame_hdr() && !parameters
->incremental())
1422 Output_section
* hdr_os
=
1423 this->choose_output_section(NULL
, ".eh_frame_hdr",
1424 elfcpp::SHT_PROGBITS
,
1425 elfcpp::SHF_ALLOC
, false,
1426 ORDER_EHFRAME
, false);
1430 Eh_frame_hdr
* hdr_posd
= new Eh_frame_hdr(os
,
1431 this->eh_frame_data_
);
1432 hdr_os
->add_output_section_data(hdr_posd
);
1434 hdr_os
->set_after_input_sections();
1436 if (!this->script_options_
->saw_phdrs_clause())
1438 Output_segment
* hdr_oseg
;
1439 hdr_oseg
= this->make_output_segment(elfcpp::PT_GNU_EH_FRAME
,
1441 hdr_oseg
->add_output_section_to_nonload(hdr_os
,
1445 this->eh_frame_data_
->set_eh_frame_hdr(hdr_posd
);
1453 // Add an exception frame for a PLT. This is called from target code.
1456 Layout::add_eh_frame_for_plt(Output_data
* plt
, const unsigned char* cie_data
,
1457 size_t cie_length
, const unsigned char* fde_data
,
1460 if (parameters
->incremental())
1462 // FIXME: Maybe this could work some day....
1465 Output_section
* os
= this->make_eh_frame_section(NULL
);
1468 this->eh_frame_data_
->add_ehframe_for_plt(plt
, cie_data
, cie_length
,
1469 fde_data
, fde_length
);
1470 if (!this->added_eh_frame_data_
)
1472 os
->add_output_section_data(this->eh_frame_data_
);
1473 this->added_eh_frame_data_
= true;
1477 // Scan a .debug_info or .debug_types section, and add summary
1478 // information to the .gdb_index section.
1480 template<int size
, bool big_endian
>
1482 Layout::add_to_gdb_index(bool is_type_unit
,
1483 Sized_relobj
<size
, big_endian
>* object
,
1484 const unsigned char* symbols
,
1487 unsigned int reloc_shndx
,
1488 unsigned int reloc_type
)
1490 if (this->gdb_index_data_
== NULL
)
1492 Output_section
* os
= this->choose_output_section(NULL
, ".gdb_index",
1493 elfcpp::SHT_PROGBITS
, 0,
1494 false, ORDER_INVALID
,
1499 this->gdb_index_data_
= new Gdb_index(os
);
1500 os
->add_output_section_data(this->gdb_index_data_
);
1501 os
->set_after_input_sections();
1504 this->gdb_index_data_
->scan_debug_info(is_type_unit
, object
, symbols
,
1505 symbols_size
, shndx
, reloc_shndx
,
1509 // Add POSD to an output section using NAME, TYPE, and FLAGS. Return
1510 // the output section.
1513 Layout::add_output_section_data(const char* name
, elfcpp::Elf_Word type
,
1514 elfcpp::Elf_Xword flags
,
1515 Output_section_data
* posd
,
1516 Output_section_order order
, bool is_relro
)
1518 Output_section
* os
= this->choose_output_section(NULL
, name
, type
, flags
,
1519 false, order
, is_relro
);
1521 os
->add_output_section_data(posd
);
1525 // Map section flags to segment flags.
1528 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags
)
1530 elfcpp::Elf_Word ret
= elfcpp::PF_R
;
1531 if ((flags
& elfcpp::SHF_WRITE
) != 0)
1532 ret
|= elfcpp::PF_W
;
1533 if ((flags
& elfcpp::SHF_EXECINSTR
) != 0)
1534 ret
|= elfcpp::PF_X
;
1538 // Make a new Output_section, and attach it to segments as
1539 // appropriate. ORDER is the order in which this section should
1540 // appear in the output segment. IS_RELRO is true if this is a relro
1541 // (read-only after relocations) section.
1544 Layout::make_output_section(const char* name
, elfcpp::Elf_Word type
,
1545 elfcpp::Elf_Xword flags
,
1546 Output_section_order order
, bool is_relro
)
1549 if ((flags
& elfcpp::SHF_ALLOC
) == 0
1550 && strcmp(parameters
->options().compress_debug_sections(), "none") != 0
1551 && is_compressible_debug_section(name
))
1552 os
= new Output_compressed_section(¶meters
->options(), name
, type
,
1554 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1555 && parameters
->options().strip_debug_non_line()
1556 && strcmp(".debug_abbrev", name
) == 0)
1558 os
= this->debug_abbrev_
= new Output_reduced_debug_abbrev_section(
1560 if (this->debug_info_
)
1561 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1563 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1564 && parameters
->options().strip_debug_non_line()
1565 && strcmp(".debug_info", name
) == 0)
1567 os
= this->debug_info_
= new Output_reduced_debug_info_section(
1569 if (this->debug_abbrev_
)
1570 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1574 // Sometimes .init_array*, .preinit_array* and .fini_array* do
1575 // not have correct section types. Force them here.
1576 if (type
== elfcpp::SHT_PROGBITS
)
1578 if (is_prefix_of(".init_array", name
))
1579 type
= elfcpp::SHT_INIT_ARRAY
;
1580 else if (is_prefix_of(".preinit_array", name
))
1581 type
= elfcpp::SHT_PREINIT_ARRAY
;
1582 else if (is_prefix_of(".fini_array", name
))
1583 type
= elfcpp::SHT_FINI_ARRAY
;
1586 // FIXME: const_cast is ugly.
1587 Target
* target
= const_cast<Target
*>(¶meters
->target());
1588 os
= target
->make_output_section(name
, type
, flags
);
1591 // With -z relro, we have to recognize the special sections by name.
1592 // There is no other way.
1593 bool is_relro_local
= false;
1594 if (!this->script_options_
->saw_sections_clause()
1595 && parameters
->options().relro()
1596 && (flags
& elfcpp::SHF_ALLOC
) != 0
1597 && (flags
& elfcpp::SHF_WRITE
) != 0)
1599 if (type
== elfcpp::SHT_PROGBITS
)
1601 if ((flags
& elfcpp::SHF_TLS
) != 0)
1603 else if (strcmp(name
, ".data.rel.ro") == 0)
1605 else if (strcmp(name
, ".data.rel.ro.local") == 0)
1608 is_relro_local
= true;
1610 else if (strcmp(name
, ".ctors") == 0
1611 || strcmp(name
, ".dtors") == 0
1612 || strcmp(name
, ".jcr") == 0)
1615 else if (type
== elfcpp::SHT_INIT_ARRAY
1616 || type
== elfcpp::SHT_FINI_ARRAY
1617 || type
== elfcpp::SHT_PREINIT_ARRAY
)
1624 if (order
== ORDER_INVALID
&& (flags
& elfcpp::SHF_ALLOC
) != 0)
1625 order
= this->default_section_order(os
, is_relro_local
);
1627 os
->set_order(order
);
1629 parameters
->target().new_output_section(os
);
1631 this->section_list_
.push_back(os
);
1633 // The GNU linker by default sorts some sections by priority, so we
1634 // do the same. We need to know that this might happen before we
1635 // attach any input sections.
1636 if (!this->script_options_
->saw_sections_clause()
1637 && !parameters
->options().relocatable()
1638 && (strcmp(name
, ".init_array") == 0
1639 || strcmp(name
, ".fini_array") == 0
1640 || (!parameters
->options().ctors_in_init_array()
1641 && (strcmp(name
, ".ctors") == 0
1642 || strcmp(name
, ".dtors") == 0))))
1643 os
->set_may_sort_attached_input_sections();
1645 // The GNU linker by default sorts .text.{unlikely,exit,startup,hot}
1646 // sections before other .text sections. We are compatible. We
1647 // need to know that this might happen before we attach any input
1649 if (!this->script_options_
->saw_sections_clause()
1650 && !this->is_section_ordering_specified()
1651 && !parameters
->options().relocatable()
1652 && strcmp(name
, ".text") == 0)
1653 os
->set_may_sort_attached_input_sections();
1655 // Check for .stab*str sections, as .stab* sections need to link to
1657 if (type
== elfcpp::SHT_STRTAB
1658 && !this->have_stabstr_section_
1659 && strncmp(name
, ".stab", 5) == 0
1660 && strcmp(name
+ strlen(name
) - 3, "str") == 0)
1661 this->have_stabstr_section_
= true;
1663 // During a full incremental link, we add patch space to most
1664 // PROGBITS and NOBITS sections. Flag those that may be
1665 // arbitrarily padded.
1666 if ((type
== elfcpp::SHT_PROGBITS
|| type
== elfcpp::SHT_NOBITS
)
1667 && order
!= ORDER_INTERP
1668 && order
!= ORDER_INIT
1669 && order
!= ORDER_PLT
1670 && order
!= ORDER_FINI
1671 && order
!= ORDER_RELRO_LAST
1672 && order
!= ORDER_NON_RELRO_FIRST
1673 && strcmp(name
, ".eh_frame") != 0
1674 && strcmp(name
, ".ctors") != 0
1675 && strcmp(name
, ".dtors") != 0
1676 && strcmp(name
, ".jcr") != 0)
1678 os
->set_is_patch_space_allowed();
1680 // Certain sections require "holes" to be filled with
1681 // specific fill patterns. These fill patterns may have
1682 // a minimum size, so we must prevent allocations from the
1683 // free list that leave a hole smaller than the minimum.
1684 if (strcmp(name
, ".debug_info") == 0)
1685 os
->set_free_space_fill(new Output_fill_debug_info(false));
1686 else if (strcmp(name
, ".debug_types") == 0)
1687 os
->set_free_space_fill(new Output_fill_debug_info(true));
1688 else if (strcmp(name
, ".debug_line") == 0)
1689 os
->set_free_space_fill(new Output_fill_debug_line());
1692 // If we have already attached the sections to segments, then we
1693 // need to attach this one now. This happens for sections created
1694 // directly by the linker.
1695 if (this->sections_are_attached_
)
1696 this->attach_section_to_segment(¶meters
->target(), os
);
1701 // Return the default order in which a section should be placed in an
1702 // output segment. This function captures a lot of the ideas in
1703 // ld/scripttempl/elf.sc in the GNU linker. Note that the order of a
1704 // linker created section is normally set when the section is created;
1705 // this function is used for input sections.
1707 Output_section_order
1708 Layout::default_section_order(Output_section
* os
, bool is_relro_local
)
1710 gold_assert((os
->flags() & elfcpp::SHF_ALLOC
) != 0);
1711 bool is_write
= (os
->flags() & elfcpp::SHF_WRITE
) != 0;
1712 bool is_execinstr
= (os
->flags() & elfcpp::SHF_EXECINSTR
) != 0;
1713 bool is_bss
= false;
1718 case elfcpp::SHT_PROGBITS
:
1720 case elfcpp::SHT_NOBITS
:
1723 case elfcpp::SHT_RELA
:
1724 case elfcpp::SHT_REL
:
1726 return ORDER_DYNAMIC_RELOCS
;
1728 case elfcpp::SHT_HASH
:
1729 case elfcpp::SHT_DYNAMIC
:
1730 case elfcpp::SHT_SHLIB
:
1731 case elfcpp::SHT_DYNSYM
:
1732 case elfcpp::SHT_GNU_HASH
:
1733 case elfcpp::SHT_GNU_verdef
:
1734 case elfcpp::SHT_GNU_verneed
:
1735 case elfcpp::SHT_GNU_versym
:
1737 return ORDER_DYNAMIC_LINKER
;
1739 case elfcpp::SHT_NOTE
:
1740 return is_write
? ORDER_RW_NOTE
: ORDER_RO_NOTE
;
1743 if ((os
->flags() & elfcpp::SHF_TLS
) != 0)
1744 return is_bss
? ORDER_TLS_BSS
: ORDER_TLS_DATA
;
1746 if (!is_bss
&& !is_write
)
1750 if (strcmp(os
->name(), ".init") == 0)
1752 else if (strcmp(os
->name(), ".fini") == 0)
1755 return is_execinstr
? ORDER_TEXT
: ORDER_READONLY
;
1759 return is_relro_local
? ORDER_RELRO_LOCAL
: ORDER_RELRO
;
1761 if (os
->is_small_section())
1762 return is_bss
? ORDER_SMALL_BSS
: ORDER_SMALL_DATA
;
1763 if (os
->is_large_section())
1764 return is_bss
? ORDER_LARGE_BSS
: ORDER_LARGE_DATA
;
1766 return is_bss
? ORDER_BSS
: ORDER_DATA
;
1769 // Attach output sections to segments. This is called after we have
1770 // seen all the input sections.
1773 Layout::attach_sections_to_segments(const Target
* target
)
1775 for (Section_list::iterator p
= this->section_list_
.begin();
1776 p
!= this->section_list_
.end();
1778 this->attach_section_to_segment(target
, *p
);
1780 this->sections_are_attached_
= true;
1783 // Attach an output section to a segment.
1786 Layout::attach_section_to_segment(const Target
* target
, Output_section
* os
)
1788 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0)
1789 this->unattached_section_list_
.push_back(os
);
1791 this->attach_allocated_section_to_segment(target
, os
);
1794 // Attach an allocated output section to a segment.
1797 Layout::attach_allocated_section_to_segment(const Target
* target
,
1800 elfcpp::Elf_Xword flags
= os
->flags();
1801 gold_assert((flags
& elfcpp::SHF_ALLOC
) != 0);
1803 if (parameters
->options().relocatable())
1806 // If we have a SECTIONS clause, we can't handle the attachment to
1807 // segments until after we've seen all the sections.
1808 if (this->script_options_
->saw_sections_clause())
1811 gold_assert(!this->script_options_
->saw_phdrs_clause());
1813 // This output section goes into a PT_LOAD segment.
1815 elfcpp::Elf_Word seg_flags
= Layout::section_flags_to_segment(flags
);
1817 // If this output section's segment has extra flags that need to be set,
1818 // coming from a linker plugin, do that.
1819 seg_flags
|= os
->extra_segment_flags();
1821 // Check for --section-start.
1823 bool is_address_set
= parameters
->options().section_start(os
->name(), &addr
);
1825 // In general the only thing we really care about for PT_LOAD
1826 // segments is whether or not they are writable or executable,
1827 // so that is how we search for them.
1828 // Large data sections also go into their own PT_LOAD segment.
1829 // People who need segments sorted on some other basis will
1830 // have to use a linker script.
1832 Segment_list::const_iterator p
;
1833 if (!os
->is_unique_segment())
1835 for (p
= this->segment_list_
.begin();
1836 p
!= this->segment_list_
.end();
1839 if ((*p
)->type() != elfcpp::PT_LOAD
)
1841 if ((*p
)->is_unique_segment())
1843 if (!parameters
->options().omagic()
1844 && ((*p
)->flags() & elfcpp::PF_W
) != (seg_flags
& elfcpp::PF_W
))
1846 if ((target
->isolate_execinstr() || parameters
->options().rosegment())
1847 && ((*p
)->flags() & elfcpp::PF_X
) != (seg_flags
& elfcpp::PF_X
))
1849 // If -Tbss was specified, we need to separate the data and BSS
1851 if (parameters
->options().user_set_Tbss())
1853 if ((os
->type() == elfcpp::SHT_NOBITS
)
1854 == (*p
)->has_any_data_sections())
1857 if (os
->is_large_data_section() && !(*p
)->is_large_data_segment())
1862 if ((*p
)->are_addresses_set())
1865 (*p
)->add_initial_output_data(os
);
1866 (*p
)->update_flags_for_output_section(seg_flags
);
1867 (*p
)->set_addresses(addr
, addr
);
1871 (*p
)->add_output_section_to_load(this, os
, seg_flags
);
1876 if (p
== this->segment_list_
.end()
1877 || os
->is_unique_segment())
1879 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_LOAD
,
1881 if (os
->is_large_data_section())
1882 oseg
->set_is_large_data_segment();
1883 oseg
->add_output_section_to_load(this, os
, seg_flags
);
1885 oseg
->set_addresses(addr
, addr
);
1886 // Check if segment should be marked unique. For segments marked
1887 // unique by linker plugins, set the new alignment if specified.
1888 if (os
->is_unique_segment())
1890 oseg
->set_is_unique_segment();
1891 if (os
->segment_alignment() != 0)
1892 oseg
->set_minimum_p_align(os
->segment_alignment());
1896 // If we see a loadable SHT_NOTE section, we create a PT_NOTE
1898 if (os
->type() == elfcpp::SHT_NOTE
)
1900 // See if we already have an equivalent PT_NOTE segment.
1901 for (p
= this->segment_list_
.begin();
1902 p
!= segment_list_
.end();
1905 if ((*p
)->type() == elfcpp::PT_NOTE
1906 && (((*p
)->flags() & elfcpp::PF_W
)
1907 == (seg_flags
& elfcpp::PF_W
)))
1909 (*p
)->add_output_section_to_nonload(os
, seg_flags
);
1914 if (p
== this->segment_list_
.end())
1916 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_NOTE
,
1918 oseg
->add_output_section_to_nonload(os
, seg_flags
);
1922 // If we see a loadable SHF_TLS section, we create a PT_TLS
1923 // segment. There can only be one such segment.
1924 if ((flags
& elfcpp::SHF_TLS
) != 0)
1926 if (this->tls_segment_
== NULL
)
1927 this->make_output_segment(elfcpp::PT_TLS
, seg_flags
);
1928 this->tls_segment_
->add_output_section_to_nonload(os
, seg_flags
);
1931 // If -z relro is in effect, and we see a relro section, we create a
1932 // PT_GNU_RELRO segment. There can only be one such segment.
1933 if (os
->is_relro() && parameters
->options().relro())
1935 gold_assert(seg_flags
== (elfcpp::PF_R
| elfcpp::PF_W
));
1936 if (this->relro_segment_
== NULL
)
1937 this->make_output_segment(elfcpp::PT_GNU_RELRO
, seg_flags
);
1938 this->relro_segment_
->add_output_section_to_nonload(os
, seg_flags
);
1941 // If we see a section named .interp, put it into a PT_INTERP
1942 // segment. This seems broken to me, but this is what GNU ld does,
1943 // and glibc expects it.
1944 if (strcmp(os
->name(), ".interp") == 0
1945 && !this->script_options_
->saw_phdrs_clause())
1947 if (this->interp_segment_
== NULL
)
1948 this->make_output_segment(elfcpp::PT_INTERP
, seg_flags
);
1950 gold_warning(_("multiple '.interp' sections in input files "
1951 "may cause confusing PT_INTERP segment"));
1952 this->interp_segment_
->add_output_section_to_nonload(os
, seg_flags
);
1956 // Make an output section for a script.
1959 Layout::make_output_section_for_script(
1961 Script_sections::Section_type section_type
)
1963 name
= this->namepool_
.add(name
, false, NULL
);
1964 elfcpp::Elf_Xword sh_flags
= elfcpp::SHF_ALLOC
;
1965 if (section_type
== Script_sections::ST_NOLOAD
)
1967 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_PROGBITS
,
1968 sh_flags
, ORDER_INVALID
,
1970 os
->set_found_in_sections_clause();
1971 if (section_type
== Script_sections::ST_NOLOAD
)
1972 os
->set_is_noload();
1976 // Return the number of segments we expect to see.
1979 Layout::expected_segment_count() const
1981 size_t ret
= this->segment_list_
.size();
1983 // If we didn't see a SECTIONS clause in a linker script, we should
1984 // already have the complete list of segments. Otherwise we ask the
1985 // SECTIONS clause how many segments it expects, and add in the ones
1986 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
1988 if (!this->script_options_
->saw_sections_clause())
1992 const Script_sections
* ss
= this->script_options_
->script_sections();
1993 return ret
+ ss
->expected_segment_count(this);
1997 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
1998 // is whether we saw a .note.GNU-stack section in the object file.
1999 // GNU_STACK_FLAGS is the section flags. The flags give the
2000 // protection required for stack memory. We record this in an
2001 // executable as a PT_GNU_STACK segment. If an object file does not
2002 // have a .note.GNU-stack segment, we must assume that it is an old
2003 // object. On some targets that will force an executable stack.
2006 Layout::layout_gnu_stack(bool seen_gnu_stack
, uint64_t gnu_stack_flags
,
2009 if (!seen_gnu_stack
)
2011 this->input_without_gnu_stack_note_
= true;
2012 if (parameters
->options().warn_execstack()
2013 && parameters
->target().is_default_stack_executable())
2014 gold_warning(_("%s: missing .note.GNU-stack section"
2015 " implies executable stack"),
2016 obj
->name().c_str());
2020 this->input_with_gnu_stack_note_
= true;
2021 if ((gnu_stack_flags
& elfcpp::SHF_EXECINSTR
) != 0)
2023 this->input_requires_executable_stack_
= true;
2024 if (parameters
->options().warn_execstack()
2025 || parameters
->options().is_stack_executable())
2026 gold_warning(_("%s: requires executable stack"),
2027 obj
->name().c_str());
2032 // Create automatic note sections.
2035 Layout::create_notes()
2037 this->create_gold_note();
2038 this->create_executable_stack_info();
2039 this->create_build_id();
2042 // Create the dynamic sections which are needed before we read the
2046 Layout::create_initial_dynamic_sections(Symbol_table
* symtab
)
2048 if (parameters
->doing_static_link())
2051 this->dynamic_section_
= this->choose_output_section(NULL
, ".dynamic",
2052 elfcpp::SHT_DYNAMIC
,
2054 | elfcpp::SHF_WRITE
),
2058 // A linker script may discard .dynamic, so check for NULL.
2059 if (this->dynamic_section_
!= NULL
)
2061 this->dynamic_symbol_
=
2062 symtab
->define_in_output_data("_DYNAMIC", NULL
,
2063 Symbol_table::PREDEFINED
,
2064 this->dynamic_section_
, 0, 0,
2065 elfcpp::STT_OBJECT
, elfcpp::STB_LOCAL
,
2066 elfcpp::STV_HIDDEN
, 0, false, false);
2068 this->dynamic_data_
= new Output_data_dynamic(&this->dynpool_
);
2070 this->dynamic_section_
->add_output_section_data(this->dynamic_data_
);
2074 // For each output section whose name can be represented as C symbol,
2075 // define __start and __stop symbols for the section. This is a GNU
2079 Layout::define_section_symbols(Symbol_table
* symtab
)
2081 for (Section_list::const_iterator p
= this->section_list_
.begin();
2082 p
!= this->section_list_
.end();
2085 const char* const name
= (*p
)->name();
2086 if (is_cident(name
))
2088 const std::string
name_string(name
);
2089 const std::string
start_name(cident_section_start_prefix
2091 const std::string
stop_name(cident_section_stop_prefix
2094 symtab
->define_in_output_data(start_name
.c_str(),
2096 Symbol_table::PREDEFINED
,
2102 elfcpp::STV_DEFAULT
,
2104 false, // offset_is_from_end
2105 true); // only_if_ref
2107 symtab
->define_in_output_data(stop_name
.c_str(),
2109 Symbol_table::PREDEFINED
,
2115 elfcpp::STV_DEFAULT
,
2117 true, // offset_is_from_end
2118 true); // only_if_ref
2123 // Define symbols for group signatures.
2126 Layout::define_group_signatures(Symbol_table
* symtab
)
2128 for (Group_signatures::iterator p
= this->group_signatures_
.begin();
2129 p
!= this->group_signatures_
.end();
2132 Symbol
* sym
= symtab
->lookup(p
->signature
, NULL
);
2134 p
->section
->set_info_symndx(sym
);
2137 // Force the name of the group section to the group
2138 // signature, and use the group's section symbol as the
2139 // signature symbol.
2140 if (strcmp(p
->section
->name(), p
->signature
) != 0)
2142 const char* name
= this->namepool_
.add(p
->signature
,
2144 p
->section
->set_name(name
);
2146 p
->section
->set_needs_symtab_index();
2147 p
->section
->set_info_section_symndx(p
->section
);
2151 this->group_signatures_
.clear();
2154 // Find the first read-only PT_LOAD segment, creating one if
2158 Layout::find_first_load_seg(const Target
* target
)
2160 Output_segment
* best
= NULL
;
2161 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
2162 p
!= this->segment_list_
.end();
2165 if ((*p
)->type() == elfcpp::PT_LOAD
2166 && ((*p
)->flags() & elfcpp::PF_R
) != 0
2167 && (parameters
->options().omagic()
2168 || ((*p
)->flags() & elfcpp::PF_W
) == 0)
2169 && (!target
->isolate_execinstr()
2170 || ((*p
)->flags() & elfcpp::PF_X
) == 0))
2172 if (best
== NULL
|| this->segment_precedes(*p
, best
))
2179 gold_assert(!this->script_options_
->saw_phdrs_clause());
2181 Output_segment
* load_seg
= this->make_output_segment(elfcpp::PT_LOAD
,
2186 // Save states of all current output segments. Store saved states
2187 // in SEGMENT_STATES.
2190 Layout::save_segments(Segment_states
* segment_states
)
2192 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
2193 p
!= this->segment_list_
.end();
2196 Output_segment
* segment
= *p
;
2198 Output_segment
* copy
= new Output_segment(*segment
);
2199 (*segment_states
)[segment
] = copy
;
2203 // Restore states of output segments and delete any segment not found in
2207 Layout::restore_segments(const Segment_states
* segment_states
)
2209 // Go through the segment list and remove any segment added in the
2211 this->tls_segment_
= NULL
;
2212 this->relro_segment_
= NULL
;
2213 Segment_list::iterator list_iter
= this->segment_list_
.begin();
2214 while (list_iter
!= this->segment_list_
.end())
2216 Output_segment
* segment
= *list_iter
;
2217 Segment_states::const_iterator states_iter
=
2218 segment_states
->find(segment
);
2219 if (states_iter
!= segment_states
->end())
2221 const Output_segment
* copy
= states_iter
->second
;
2222 // Shallow copy to restore states.
2225 // Also fix up TLS and RELRO segment pointers as appropriate.
2226 if (segment
->type() == elfcpp::PT_TLS
)
2227 this->tls_segment_
= segment
;
2228 else if (segment
->type() == elfcpp::PT_GNU_RELRO
)
2229 this->relro_segment_
= segment
;
2235 list_iter
= this->segment_list_
.erase(list_iter
);
2236 // This is a segment created during section layout. It should be
2237 // safe to remove it since we should have removed all pointers to it.
2243 // Clean up after relaxation so that sections can be laid out again.
2246 Layout::clean_up_after_relaxation()
2248 // Restore the segments to point state just prior to the relaxation loop.
2249 Script_sections
* script_section
= this->script_options_
->script_sections();
2250 script_section
->release_segments();
2251 this->restore_segments(this->segment_states_
);
2253 // Reset section addresses and file offsets
2254 for (Section_list::iterator p
= this->section_list_
.begin();
2255 p
!= this->section_list_
.end();
2258 (*p
)->restore_states();
2260 // If an input section changes size because of relaxation,
2261 // we need to adjust the section offsets of all input sections.
2262 // after such a section.
2263 if ((*p
)->section_offsets_need_adjustment())
2264 (*p
)->adjust_section_offsets();
2266 (*p
)->reset_address_and_file_offset();
2269 // Reset special output object address and file offsets.
2270 for (Data_list::iterator p
= this->special_output_list_
.begin();
2271 p
!= this->special_output_list_
.end();
2273 (*p
)->reset_address_and_file_offset();
2275 // A linker script may have created some output section data objects.
2276 // They are useless now.
2277 for (Output_section_data_list::const_iterator p
=
2278 this->script_output_section_data_list_
.begin();
2279 p
!= this->script_output_section_data_list_
.end();
2282 this->script_output_section_data_list_
.clear();
2285 // Prepare for relaxation.
2288 Layout::prepare_for_relaxation()
2290 // Create an relaxation debug check if in debugging mode.
2291 if (is_debugging_enabled(DEBUG_RELAXATION
))
2292 this->relaxation_debug_check_
= new Relaxation_debug_check();
2294 // Save segment states.
2295 this->segment_states_
= new Segment_states();
2296 this->save_segments(this->segment_states_
);
2298 for(Section_list::const_iterator p
= this->section_list_
.begin();
2299 p
!= this->section_list_
.end();
2301 (*p
)->save_states();
2303 if (is_debugging_enabled(DEBUG_RELAXATION
))
2304 this->relaxation_debug_check_
->check_output_data_for_reset_values(
2305 this->section_list_
, this->special_output_list_
);
2307 // Also enable recording of output section data from scripts.
2308 this->record_output_section_data_from_script_
= true;
2311 // Relaxation loop body: If target has no relaxation, this runs only once
2312 // Otherwise, the target relaxation hook is called at the end of
2313 // each iteration. If the hook returns true, it means re-layout of
2314 // section is required.
2316 // The number of segments created by a linking script without a PHDRS
2317 // clause may be affected by section sizes and alignments. There is
2318 // a remote chance that relaxation causes different number of PT_LOAD
2319 // segments are created and sections are attached to different segments.
2320 // Therefore, we always throw away all segments created during section
2321 // layout. In order to be able to restart the section layout, we keep
2322 // a copy of the segment list right before the relaxation loop and use
2323 // that to restore the segments.
2325 // PASS is the current relaxation pass number.
2326 // SYMTAB is a symbol table.
2327 // PLOAD_SEG is the address of a pointer for the load segment.
2328 // PHDR_SEG is a pointer to the PHDR segment.
2329 // SEGMENT_HEADERS points to the output segment header.
2330 // FILE_HEADER points to the output file header.
2331 // PSHNDX is the address to store the output section index.
2334 Layout::relaxation_loop_body(
2337 Symbol_table
* symtab
,
2338 Output_segment
** pload_seg
,
2339 Output_segment
* phdr_seg
,
2340 Output_segment_headers
* segment_headers
,
2341 Output_file_header
* file_header
,
2342 unsigned int* pshndx
)
2344 // If this is not the first iteration, we need to clean up after
2345 // relaxation so that we can lay out the sections again.
2347 this->clean_up_after_relaxation();
2349 // If there is a SECTIONS clause, put all the input sections into
2350 // the required order.
2351 Output_segment
* load_seg
;
2352 if (this->script_options_
->saw_sections_clause())
2353 load_seg
= this->set_section_addresses_from_script(symtab
);
2354 else if (parameters
->options().relocatable())
2357 load_seg
= this->find_first_load_seg(target
);
2359 if (parameters
->options().oformat_enum()
2360 != General_options::OBJECT_FORMAT_ELF
)
2363 // If the user set the address of the text segment, that may not be
2364 // compatible with putting the segment headers and file headers into
2366 if (parameters
->options().user_set_Ttext()
2367 && parameters
->options().Ttext() % target
->abi_pagesize() != 0)
2373 gold_assert(phdr_seg
== NULL
2375 || this->script_options_
->saw_sections_clause());
2377 // If the address of the load segment we found has been set by
2378 // --section-start rather than by a script, then adjust the VMA and
2379 // LMA downward if possible to include the file and section headers.
2380 uint64_t header_gap
= 0;
2381 if (load_seg
!= NULL
2382 && load_seg
->are_addresses_set()
2383 && !this->script_options_
->saw_sections_clause()
2384 && !parameters
->options().relocatable())
2386 file_header
->finalize_data_size();
2387 segment_headers
->finalize_data_size();
2388 size_t sizeof_headers
= (file_header
->data_size()
2389 + segment_headers
->data_size());
2390 const uint64_t abi_pagesize
= target
->abi_pagesize();
2391 uint64_t hdr_paddr
= load_seg
->paddr() - sizeof_headers
;
2392 hdr_paddr
&= ~(abi_pagesize
- 1);
2393 uint64_t subtract
= load_seg
->paddr() - hdr_paddr
;
2394 if (load_seg
->paddr() < subtract
|| load_seg
->vaddr() < subtract
)
2398 load_seg
->set_addresses(load_seg
->vaddr() - subtract
,
2399 load_seg
->paddr() - subtract
);
2400 header_gap
= subtract
- sizeof_headers
;
2404 // Lay out the segment headers.
2405 if (!parameters
->options().relocatable())
2407 gold_assert(segment_headers
!= NULL
);
2408 if (header_gap
!= 0 && load_seg
!= NULL
)
2410 Output_data_zero_fill
* z
= new Output_data_zero_fill(header_gap
, 1);
2411 load_seg
->add_initial_output_data(z
);
2413 if (load_seg
!= NULL
)
2414 load_seg
->add_initial_output_data(segment_headers
);
2415 if (phdr_seg
!= NULL
)
2416 phdr_seg
->add_initial_output_data(segment_headers
);
2419 // Lay out the file header.
2420 if (load_seg
!= NULL
)
2421 load_seg
->add_initial_output_data(file_header
);
2423 if (this->script_options_
->saw_phdrs_clause()
2424 && !parameters
->options().relocatable())
2426 // Support use of FILEHDRS and PHDRS attachments in a PHDRS
2427 // clause in a linker script.
2428 Script_sections
* ss
= this->script_options_
->script_sections();
2429 ss
->put_headers_in_phdrs(file_header
, segment_headers
);
2432 // We set the output section indexes in set_segment_offsets and
2433 // set_section_indexes.
2436 // Set the file offsets of all the segments, and all the sections
2439 if (!parameters
->options().relocatable())
2440 off
= this->set_segment_offsets(target
, load_seg
, pshndx
);
2442 off
= this->set_relocatable_section_offsets(file_header
, pshndx
);
2444 // Verify that the dummy relaxation does not change anything.
2445 if (is_debugging_enabled(DEBUG_RELAXATION
))
2448 this->relaxation_debug_check_
->read_sections(this->section_list_
);
2450 this->relaxation_debug_check_
->verify_sections(this->section_list_
);
2453 *pload_seg
= load_seg
;
2457 // Search the list of patterns and find the postion of the given section
2458 // name in the output section. If the section name matches a glob
2459 // pattern and a non-glob name, then the non-glob position takes
2460 // precedence. Return 0 if no match is found.
2463 Layout::find_section_order_index(const std::string
& section_name
)
2465 Unordered_map
<std::string
, unsigned int>::iterator map_it
;
2466 map_it
= this->input_section_position_
.find(section_name
);
2467 if (map_it
!= this->input_section_position_
.end())
2468 return map_it
->second
;
2470 // Absolute match failed. Linear search the glob patterns.
2471 std::vector
<std::string
>::iterator it
;
2472 for (it
= this->input_section_glob_
.begin();
2473 it
!= this->input_section_glob_
.end();
2476 if (fnmatch((*it
).c_str(), section_name
.c_str(), FNM_NOESCAPE
) == 0)
2478 map_it
= this->input_section_position_
.find(*it
);
2479 gold_assert(map_it
!= this->input_section_position_
.end());
2480 return map_it
->second
;
2486 // Read the sequence of input sections from the file specified with
2487 // option --section-ordering-file.
2490 Layout::read_layout_from_file()
2492 const char* filename
= parameters
->options().section_ordering_file();
2498 gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
2499 filename
, strerror(errno
));
2501 std::getline(in
, line
); // this chops off the trailing \n, if any
2502 unsigned int position
= 1;
2503 this->set_section_ordering_specified();
2507 if (!line
.empty() && line
[line
.length() - 1] == '\r') // Windows
2508 line
.resize(line
.length() - 1);
2509 // Ignore comments, beginning with '#'
2512 std::getline(in
, line
);
2515 this->input_section_position_
[line
] = position
;
2516 // Store all glob patterns in a vector.
2517 if (is_wildcard_string(line
.c_str()))
2518 this->input_section_glob_
.push_back(line
);
2520 std::getline(in
, line
);
2524 // Finalize the layout. When this is called, we have created all the
2525 // output sections and all the output segments which are based on
2526 // input sections. We have several things to do, and we have to do
2527 // them in the right order, so that we get the right results correctly
2530 // 1) Finalize the list of output segments and create the segment
2533 // 2) Finalize the dynamic symbol table and associated sections.
2535 // 3) Determine the final file offset of all the output segments.
2537 // 4) Determine the final file offset of all the SHF_ALLOC output
2540 // 5) Create the symbol table sections and the section name table
2543 // 6) Finalize the symbol table: set symbol values to their final
2544 // value and make a final determination of which symbols are going
2545 // into the output symbol table.
2547 // 7) Create the section table header.
2549 // 8) Determine the final file offset of all the output sections which
2550 // are not SHF_ALLOC, including the section table header.
2552 // 9) Finalize the ELF file header.
2554 // This function returns the size of the output file.
2557 Layout::finalize(const Input_objects
* input_objects
, Symbol_table
* symtab
,
2558 Target
* target
, const Task
* task
)
2560 target
->finalize_sections(this, input_objects
, symtab
);
2562 this->count_local_symbols(task
, input_objects
);
2564 this->link_stabs_sections();
2566 Output_segment
* phdr_seg
= NULL
;
2567 if (!parameters
->options().relocatable() && !parameters
->doing_static_link())
2569 // There was a dynamic object in the link. We need to create
2570 // some information for the dynamic linker.
2572 // Create the PT_PHDR segment which will hold the program
2574 if (!this->script_options_
->saw_phdrs_clause())
2575 phdr_seg
= this->make_output_segment(elfcpp::PT_PHDR
, elfcpp::PF_R
);
2577 // Create the dynamic symbol table, including the hash table.
2578 Output_section
* dynstr
;
2579 std::vector
<Symbol
*> dynamic_symbols
;
2580 unsigned int local_dynamic_count
;
2581 Versions
versions(*this->script_options()->version_script_info(),
2583 this->create_dynamic_symtab(input_objects
, symtab
, &dynstr
,
2584 &local_dynamic_count
, &dynamic_symbols
,
2587 // Create the .interp section to hold the name of the
2588 // interpreter, and put it in a PT_INTERP segment. Don't do it
2589 // if we saw a .interp section in an input file.
2590 if ((!parameters
->options().shared()
2591 || parameters
->options().dynamic_linker() != NULL
)
2592 && this->interp_segment_
== NULL
)
2593 this->create_interp(target
);
2595 // Finish the .dynamic section to hold the dynamic data, and put
2596 // it in a PT_DYNAMIC segment.
2597 this->finish_dynamic_section(input_objects
, symtab
);
2599 // We should have added everything we need to the dynamic string
2601 this->dynpool_
.set_string_offsets();
2603 // Create the version sections. We can't do this until the
2604 // dynamic string table is complete.
2605 this->create_version_sections(&versions
, symtab
, local_dynamic_count
,
2606 dynamic_symbols
, dynstr
);
2608 // Set the size of the _DYNAMIC symbol. We can't do this until
2609 // after we call create_version_sections.
2610 this->set_dynamic_symbol_size(symtab
);
2613 // Create segment headers.
2614 Output_segment_headers
* segment_headers
=
2615 (parameters
->options().relocatable()
2617 : new Output_segment_headers(this->segment_list_
));
2619 // Lay out the file header.
2620 Output_file_header
* file_header
= new Output_file_header(target
, symtab
,
2623 this->special_output_list_
.push_back(file_header
);
2624 if (segment_headers
!= NULL
)
2625 this->special_output_list_
.push_back(segment_headers
);
2627 // Find approriate places for orphan output sections if we are using
2629 if (this->script_options_
->saw_sections_clause())
2630 this->place_orphan_sections_in_script();
2632 Output_segment
* load_seg
;
2637 // Take a snapshot of the section layout as needed.
2638 if (target
->may_relax())
2639 this->prepare_for_relaxation();
2641 // Run the relaxation loop to lay out sections.
2644 off
= this->relaxation_loop_body(pass
, target
, symtab
, &load_seg
,
2645 phdr_seg
, segment_headers
, file_header
,
2649 while (target
->may_relax()
2650 && target
->relax(pass
, input_objects
, symtab
, this, task
));
2652 // If there is a load segment that contains the file and program headers,
2653 // provide a symbol __ehdr_start pointing there.
2654 // A program can use this to examine itself robustly.
2655 if (load_seg
!= NULL
)
2656 symtab
->define_in_output_segment("__ehdr_start", NULL
,
2657 Symbol_table::PREDEFINED
, load_seg
, 0, 0,
2658 elfcpp::STT_NOTYPE
, elfcpp::STB_GLOBAL
,
2659 elfcpp::STV_DEFAULT
, 0,
2660 Symbol::SEGMENT_START
, true);
2662 // Set the file offsets of all the non-data sections we've seen so
2663 // far which don't have to wait for the input sections. We need
2664 // this in order to finalize local symbols in non-allocated
2666 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
2668 // Set the section indexes of all unallocated sections seen so far,
2669 // in case any of them are somehow referenced by a symbol.
2670 shndx
= this->set_section_indexes(shndx
);
2672 // Create the symbol table sections.
2673 this->create_symtab_sections(input_objects
, symtab
, shndx
, &off
);
2674 if (!parameters
->doing_static_link())
2675 this->assign_local_dynsym_offsets(input_objects
);
2677 // Process any symbol assignments from a linker script. This must
2678 // be called after the symbol table has been finalized.
2679 this->script_options_
->finalize_symbols(symtab
, this);
2681 // Create the incremental inputs sections.
2682 if (this->incremental_inputs_
)
2684 this->incremental_inputs_
->finalize();
2685 this->create_incremental_info_sections(symtab
);
2688 // Create the .shstrtab section.
2689 Output_section
* shstrtab_section
= this->create_shstrtab();
2691 // Set the file offsets of the rest of the non-data sections which
2692 // don't have to wait for the input sections.
2693 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
2695 // Now that all sections have been created, set the section indexes
2696 // for any sections which haven't been done yet.
2697 shndx
= this->set_section_indexes(shndx
);
2699 // Create the section table header.
2700 this->create_shdrs(shstrtab_section
, &off
);
2702 // If there are no sections which require postprocessing, we can
2703 // handle the section names now, and avoid a resize later.
2704 if (!this->any_postprocessing_sections_
)
2706 off
= this->set_section_offsets(off
,
2707 POSTPROCESSING_SECTIONS_PASS
);
2709 this->set_section_offsets(off
,
2710 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
2713 file_header
->set_section_info(this->section_headers_
, shstrtab_section
);
2715 // Now we know exactly where everything goes in the output file
2716 // (except for non-allocated sections which require postprocessing).
2717 Output_data::layout_complete();
2719 this->output_file_size_
= off
;
2724 // Create a note header following the format defined in the ELF ABI.
2725 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
2726 // of the section to create, DESCSZ is the size of the descriptor.
2727 // ALLOCATE is true if the section should be allocated in memory.
2728 // This returns the new note section. It sets *TRAILING_PADDING to
2729 // the number of trailing zero bytes required.
2732 Layout::create_note(const char* name
, int note_type
,
2733 const char* section_name
, size_t descsz
,
2734 bool allocate
, size_t* trailing_padding
)
2736 // Authorities all agree that the values in a .note field should
2737 // be aligned on 4-byte boundaries for 32-bit binaries. However,
2738 // they differ on what the alignment is for 64-bit binaries.
2739 // The GABI says unambiguously they take 8-byte alignment:
2740 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
2741 // Other documentation says alignment should always be 4 bytes:
2742 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
2743 // GNU ld and GNU readelf both support the latter (at least as of
2744 // version 2.16.91), and glibc always generates the latter for
2745 // .note.ABI-tag (as of version 1.6), so that's the one we go with
2747 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
2748 const int size
= parameters
->target().get_size();
2750 const int size
= 32;
2753 // The contents of the .note section.
2754 size_t namesz
= strlen(name
) + 1;
2755 size_t aligned_namesz
= align_address(namesz
, size
/ 8);
2756 size_t aligned_descsz
= align_address(descsz
, size
/ 8);
2758 size_t notehdrsz
= 3 * (size
/ 8) + aligned_namesz
;
2760 unsigned char* buffer
= new unsigned char[notehdrsz
];
2761 memset(buffer
, 0, notehdrsz
);
2763 bool is_big_endian
= parameters
->target().is_big_endian();
2769 elfcpp::Swap
<32, false>::writeval(buffer
, namesz
);
2770 elfcpp::Swap
<32, false>::writeval(buffer
+ 4, descsz
);
2771 elfcpp::Swap
<32, false>::writeval(buffer
+ 8, note_type
);
2775 elfcpp::Swap
<32, true>::writeval(buffer
, namesz
);
2776 elfcpp::Swap
<32, true>::writeval(buffer
+ 4, descsz
);
2777 elfcpp::Swap
<32, true>::writeval(buffer
+ 8, note_type
);
2780 else if (size
== 64)
2784 elfcpp::Swap
<64, false>::writeval(buffer
, namesz
);
2785 elfcpp::Swap
<64, false>::writeval(buffer
+ 8, descsz
);
2786 elfcpp::Swap
<64, false>::writeval(buffer
+ 16, note_type
);
2790 elfcpp::Swap
<64, true>::writeval(buffer
, namesz
);
2791 elfcpp::Swap
<64, true>::writeval(buffer
+ 8, descsz
);
2792 elfcpp::Swap
<64, true>::writeval(buffer
+ 16, note_type
);
2798 memcpy(buffer
+ 3 * (size
/ 8), name
, namesz
);
2800 elfcpp::Elf_Xword flags
= 0;
2801 Output_section_order order
= ORDER_INVALID
;
2804 flags
= elfcpp::SHF_ALLOC
;
2805 order
= ORDER_RO_NOTE
;
2807 Output_section
* os
= this->choose_output_section(NULL
, section_name
,
2809 flags
, false, order
, false);
2813 Output_section_data
* posd
= new Output_data_const_buffer(buffer
, notehdrsz
,
2816 os
->add_output_section_data(posd
);
2818 *trailing_padding
= aligned_descsz
- descsz
;
2823 // For an executable or shared library, create a note to record the
2824 // version of gold used to create the binary.
2827 Layout::create_gold_note()
2829 if (parameters
->options().relocatable()
2830 || parameters
->incremental_update())
2833 std::string desc
= std::string("gold ") + gold::get_version_string();
2835 size_t trailing_padding
;
2836 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION
,
2837 ".note.gnu.gold-version", desc
.size(),
2838 false, &trailing_padding
);
2842 Output_section_data
* posd
= new Output_data_const(desc
, 4);
2843 os
->add_output_section_data(posd
);
2845 if (trailing_padding
> 0)
2847 posd
= new Output_data_zero_fill(trailing_padding
, 0);
2848 os
->add_output_section_data(posd
);
2852 // Record whether the stack should be executable. This can be set
2853 // from the command line using the -z execstack or -z noexecstack
2854 // options. Otherwise, if any input file has a .note.GNU-stack
2855 // section with the SHF_EXECINSTR flag set, the stack should be
2856 // executable. Otherwise, if at least one input file a
2857 // .note.GNU-stack section, and some input file has no .note.GNU-stack
2858 // section, we use the target default for whether the stack should be
2859 // executable. Otherwise, we don't generate a stack note. When
2860 // generating a object file, we create a .note.GNU-stack section with
2861 // the appropriate marking. When generating an executable or shared
2862 // library, we create a PT_GNU_STACK segment.
2865 Layout::create_executable_stack_info()
2867 bool is_stack_executable
;
2868 if (parameters
->options().is_execstack_set())
2869 is_stack_executable
= parameters
->options().is_stack_executable();
2870 else if (!this->input_with_gnu_stack_note_
)
2874 if (this->input_requires_executable_stack_
)
2875 is_stack_executable
= true;
2876 else if (this->input_without_gnu_stack_note_
)
2877 is_stack_executable
=
2878 parameters
->target().is_default_stack_executable();
2880 is_stack_executable
= false;
2883 if (parameters
->options().relocatable())
2885 const char* name
= this->namepool_
.add(".note.GNU-stack", false, NULL
);
2886 elfcpp::Elf_Xword flags
= 0;
2887 if (is_stack_executable
)
2888 flags
|= elfcpp::SHF_EXECINSTR
;
2889 this->make_output_section(name
, elfcpp::SHT_PROGBITS
, flags
,
2890 ORDER_INVALID
, false);
2894 if (this->script_options_
->saw_phdrs_clause())
2896 int flags
= elfcpp::PF_R
| elfcpp::PF_W
;
2897 if (is_stack_executable
)
2898 flags
|= elfcpp::PF_X
;
2899 this->make_output_segment(elfcpp::PT_GNU_STACK
, flags
);
2903 // If --build-id was used, set up the build ID note.
2906 Layout::create_build_id()
2908 if (!parameters
->options().user_set_build_id())
2911 const char* style
= parameters
->options().build_id();
2912 if (strcmp(style
, "none") == 0)
2915 // Set DESCSZ to the size of the note descriptor. When possible,
2916 // set DESC to the note descriptor contents.
2919 if (strcmp(style
, "md5") == 0)
2921 else if (strcmp(style
, "sha1") == 0)
2923 else if (strcmp(style
, "uuid") == 0)
2925 const size_t uuidsz
= 128 / 8;
2927 char buffer
[uuidsz
];
2928 memset(buffer
, 0, uuidsz
);
2930 int descriptor
= open_descriptor(-1, "/dev/urandom", O_RDONLY
);
2932 gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
2936 ssize_t got
= ::read(descriptor
, buffer
, uuidsz
);
2937 release_descriptor(descriptor
, true);
2939 gold_error(_("/dev/urandom: read failed: %s"), strerror(errno
));
2940 else if (static_cast<size_t>(got
) != uuidsz
)
2941 gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
2945 desc
.assign(buffer
, uuidsz
);
2948 else if (strncmp(style
, "0x", 2) == 0)
2951 const char* p
= style
+ 2;
2954 if (hex_p(p
[0]) && hex_p(p
[1]))
2956 char c
= (hex_value(p
[0]) << 4) | hex_value(p
[1]);
2960 else if (*p
== '-' || *p
== ':')
2963 gold_fatal(_("--build-id argument '%s' not a valid hex number"),
2966 descsz
= desc
.size();
2969 gold_fatal(_("unrecognized --build-id argument '%s'"), style
);
2972 size_t trailing_padding
;
2973 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID
,
2974 ".note.gnu.build-id", descsz
, true,
2981 // We know the value already, so we fill it in now.
2982 gold_assert(desc
.size() == descsz
);
2984 Output_section_data
* posd
= new Output_data_const(desc
, 4);
2985 os
->add_output_section_data(posd
);
2987 if (trailing_padding
!= 0)
2989 posd
= new Output_data_zero_fill(trailing_padding
, 0);
2990 os
->add_output_section_data(posd
);
2995 // We need to compute a checksum after we have completed the
2997 gold_assert(trailing_padding
== 0);
2998 this->build_id_note_
= new Output_data_zero_fill(descsz
, 4);
2999 os
->add_output_section_data(this->build_id_note_
);
3003 // If we have both .stabXX and .stabXXstr sections, then the sh_link
3004 // field of the former should point to the latter. I'm not sure who
3005 // started this, but the GNU linker does it, and some tools depend
3009 Layout::link_stabs_sections()
3011 if (!this->have_stabstr_section_
)
3014 for (Section_list::iterator p
= this->section_list_
.begin();
3015 p
!= this->section_list_
.end();
3018 if ((*p
)->type() != elfcpp::SHT_STRTAB
)
3021 const char* name
= (*p
)->name();
3022 if (strncmp(name
, ".stab", 5) != 0)
3025 size_t len
= strlen(name
);
3026 if (strcmp(name
+ len
- 3, "str") != 0)
3029 std::string
stab_name(name
, len
- 3);
3030 Output_section
* stab_sec
;
3031 stab_sec
= this->find_output_section(stab_name
.c_str());
3032 if (stab_sec
!= NULL
)
3033 stab_sec
->set_link_section(*p
);
3037 // Create .gnu_incremental_inputs and related sections needed
3038 // for the next run of incremental linking to check what has changed.
3041 Layout::create_incremental_info_sections(Symbol_table
* symtab
)
3043 Incremental_inputs
* incr
= this->incremental_inputs_
;
3045 gold_assert(incr
!= NULL
);
3047 // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
3048 incr
->create_data_sections(symtab
);
3050 // Add the .gnu_incremental_inputs section.
3051 const char* incremental_inputs_name
=
3052 this->namepool_
.add(".gnu_incremental_inputs", false, NULL
);
3053 Output_section
* incremental_inputs_os
=
3054 this->make_output_section(incremental_inputs_name
,
3055 elfcpp::SHT_GNU_INCREMENTAL_INPUTS
, 0,
3056 ORDER_INVALID
, false);
3057 incremental_inputs_os
->add_output_section_data(incr
->inputs_section());
3059 // Add the .gnu_incremental_symtab section.
3060 const char* incremental_symtab_name
=
3061 this->namepool_
.add(".gnu_incremental_symtab", false, NULL
);
3062 Output_section
* incremental_symtab_os
=
3063 this->make_output_section(incremental_symtab_name
,
3064 elfcpp::SHT_GNU_INCREMENTAL_SYMTAB
, 0,
3065 ORDER_INVALID
, false);
3066 incremental_symtab_os
->add_output_section_data(incr
->symtab_section());
3067 incremental_symtab_os
->set_entsize(4);
3069 // Add the .gnu_incremental_relocs section.
3070 const char* incremental_relocs_name
=
3071 this->namepool_
.add(".gnu_incremental_relocs", false, NULL
);
3072 Output_section
* incremental_relocs_os
=
3073 this->make_output_section(incremental_relocs_name
,
3074 elfcpp::SHT_GNU_INCREMENTAL_RELOCS
, 0,
3075 ORDER_INVALID
, false);
3076 incremental_relocs_os
->add_output_section_data(incr
->relocs_section());
3077 incremental_relocs_os
->set_entsize(incr
->relocs_entsize());
3079 // Add the .gnu_incremental_got_plt section.
3080 const char* incremental_got_plt_name
=
3081 this->namepool_
.add(".gnu_incremental_got_plt", false, NULL
);
3082 Output_section
* incremental_got_plt_os
=
3083 this->make_output_section(incremental_got_plt_name
,
3084 elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT
, 0,
3085 ORDER_INVALID
, false);
3086 incremental_got_plt_os
->add_output_section_data(incr
->got_plt_section());
3088 // Add the .gnu_incremental_strtab section.
3089 const char* incremental_strtab_name
=
3090 this->namepool_
.add(".gnu_incremental_strtab", false, NULL
);
3091 Output_section
* incremental_strtab_os
= this->make_output_section(incremental_strtab_name
,
3092 elfcpp::SHT_STRTAB
, 0,
3093 ORDER_INVALID
, false);
3094 Output_data_strtab
* strtab_data
=
3095 new Output_data_strtab(incr
->get_stringpool());
3096 incremental_strtab_os
->add_output_section_data(strtab_data
);
3098 incremental_inputs_os
->set_after_input_sections();
3099 incremental_symtab_os
->set_after_input_sections();
3100 incremental_relocs_os
->set_after_input_sections();
3101 incremental_got_plt_os
->set_after_input_sections();
3103 incremental_inputs_os
->set_link_section(incremental_strtab_os
);
3104 incremental_symtab_os
->set_link_section(incremental_inputs_os
);
3105 incremental_relocs_os
->set_link_section(incremental_inputs_os
);
3106 incremental_got_plt_os
->set_link_section(incremental_inputs_os
);
3109 // Return whether SEG1 should be before SEG2 in the output file. This
3110 // is based entirely on the segment type and flags. When this is
3111 // called the segment addresses have normally not yet been set.
3114 Layout::segment_precedes(const Output_segment
* seg1
,
3115 const Output_segment
* seg2
)
3117 elfcpp::Elf_Word type1
= seg1
->type();
3118 elfcpp::Elf_Word type2
= seg2
->type();
3120 // The single PT_PHDR segment is required to precede any loadable
3121 // segment. We simply make it always first.
3122 if (type1
== elfcpp::PT_PHDR
)
3124 gold_assert(type2
!= elfcpp::PT_PHDR
);
3127 if (type2
== elfcpp::PT_PHDR
)
3130 // The single PT_INTERP segment is required to precede any loadable
3131 // segment. We simply make it always second.
3132 if (type1
== elfcpp::PT_INTERP
)
3134 gold_assert(type2
!= elfcpp::PT_INTERP
);
3137 if (type2
== elfcpp::PT_INTERP
)
3140 // We then put PT_LOAD segments before any other segments.
3141 if (type1
== elfcpp::PT_LOAD
&& type2
!= elfcpp::PT_LOAD
)
3143 if (type2
== elfcpp::PT_LOAD
&& type1
!= elfcpp::PT_LOAD
)
3146 // We put the PT_TLS segment last except for the PT_GNU_RELRO
3147 // segment, because that is where the dynamic linker expects to find
3148 // it (this is just for efficiency; other positions would also work
3150 if (type1
== elfcpp::PT_TLS
3151 && type2
!= elfcpp::PT_TLS
3152 && type2
!= elfcpp::PT_GNU_RELRO
)
3154 if (type2
== elfcpp::PT_TLS
3155 && type1
!= elfcpp::PT_TLS
3156 && type1
!= elfcpp::PT_GNU_RELRO
)
3159 // We put the PT_GNU_RELRO segment last, because that is where the
3160 // dynamic linker expects to find it (as with PT_TLS, this is just
3162 if (type1
== elfcpp::PT_GNU_RELRO
&& type2
!= elfcpp::PT_GNU_RELRO
)
3164 if (type2
== elfcpp::PT_GNU_RELRO
&& type1
!= elfcpp::PT_GNU_RELRO
)
3167 const elfcpp::Elf_Word flags1
= seg1
->flags();
3168 const elfcpp::Elf_Word flags2
= seg2
->flags();
3170 // The order of non-PT_LOAD segments is unimportant. We simply sort
3171 // by the numeric segment type and flags values. There should not
3172 // be more than one segment with the same type and flags.
3173 if (type1
!= elfcpp::PT_LOAD
)
3176 return type1
< type2
;
3177 gold_assert(flags1
!= flags2
);
3178 return flags1
< flags2
;
3181 // If the addresses are set already, sort by load address.
3182 if (seg1
->are_addresses_set())
3184 if (!seg2
->are_addresses_set())
3187 unsigned int section_count1
= seg1
->output_section_count();
3188 unsigned int section_count2
= seg2
->output_section_count();
3189 if (section_count1
== 0 && section_count2
> 0)
3191 if (section_count1
> 0 && section_count2
== 0)
3194 uint64_t paddr1
= (seg1
->are_addresses_set()
3196 : seg1
->first_section_load_address());
3197 uint64_t paddr2
= (seg2
->are_addresses_set()
3199 : seg2
->first_section_load_address());
3201 if (paddr1
!= paddr2
)
3202 return paddr1
< paddr2
;
3204 else if (seg2
->are_addresses_set())
3207 // A segment which holds large data comes after a segment which does
3208 // not hold large data.
3209 if (seg1
->is_large_data_segment())
3211 if (!seg2
->is_large_data_segment())
3214 else if (seg2
->is_large_data_segment())
3217 // Otherwise, we sort PT_LOAD segments based on the flags. Readonly
3218 // segments come before writable segments. Then writable segments
3219 // with data come before writable segments without data. Then
3220 // executable segments come before non-executable segments. Then
3221 // the unlikely case of a non-readable segment comes before the
3222 // normal case of a readable segment. If there are multiple
3223 // segments with the same type and flags, we require that the
3224 // address be set, and we sort by virtual address and then physical
3226 if ((flags1
& elfcpp::PF_W
) != (flags2
& elfcpp::PF_W
))
3227 return (flags1
& elfcpp::PF_W
) == 0;
3228 if ((flags1
& elfcpp::PF_W
) != 0
3229 && seg1
->has_any_data_sections() != seg2
->has_any_data_sections())
3230 return seg1
->has_any_data_sections();
3231 if ((flags1
& elfcpp::PF_X
) != (flags2
& elfcpp::PF_X
))
3232 return (flags1
& elfcpp::PF_X
) != 0;
3233 if ((flags1
& elfcpp::PF_R
) != (flags2
& elfcpp::PF_R
))
3234 return (flags1
& elfcpp::PF_R
) == 0;
3236 // We shouldn't get here--we shouldn't create segments which we
3237 // can't distinguish. Unless of course we are using a weird linker
3238 // script or overlapping --section-start options. We could also get
3239 // here if plugins want unique segments for subsets of sections.
3240 gold_assert(this->script_options_
->saw_phdrs_clause()
3241 || parameters
->options().any_section_start()
3242 || this->is_unique_segment_for_sections_specified());
3246 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
3249 align_file_offset(off_t off
, uint64_t addr
, uint64_t abi_pagesize
)
3251 uint64_t unsigned_off
= off
;
3252 uint64_t aligned_off
= ((unsigned_off
& ~(abi_pagesize
- 1))
3253 | (addr
& (abi_pagesize
- 1)));
3254 if (aligned_off
< unsigned_off
)
3255 aligned_off
+= abi_pagesize
;
3259 // Set the file offsets of all the segments, and all the sections they
3260 // contain. They have all been created. LOAD_SEG must be be laid out
3261 // first. Return the offset of the data to follow.
3264 Layout::set_segment_offsets(const Target
* target
, Output_segment
* load_seg
,
3265 unsigned int* pshndx
)
3267 // Sort them into the final order. We use a stable sort so that we
3268 // don't randomize the order of indistinguishable segments created
3269 // by linker scripts.
3270 std::stable_sort(this->segment_list_
.begin(), this->segment_list_
.end(),
3271 Layout::Compare_segments(this));
3273 // Find the PT_LOAD segments, and set their addresses and offsets
3274 // and their section's addresses and offsets.
3275 uint64_t start_addr
;
3276 if (parameters
->options().user_set_Ttext())
3277 start_addr
= parameters
->options().Ttext();
3278 else if (parameters
->options().output_is_position_independent())
3281 start_addr
= target
->default_text_segment_address();
3283 uint64_t addr
= start_addr
;
3286 // If LOAD_SEG is NULL, then the file header and segment headers
3287 // will not be loadable. But they still need to be at offset 0 in
3288 // the file. Set their offsets now.
3289 if (load_seg
== NULL
)
3291 for (Data_list::iterator p
= this->special_output_list_
.begin();
3292 p
!= this->special_output_list_
.end();
3295 off
= align_address(off
, (*p
)->addralign());
3296 (*p
)->set_address_and_file_offset(0, off
);
3297 off
+= (*p
)->data_size();
3301 unsigned int increase_relro
= this->increase_relro_
;
3302 if (this->script_options_
->saw_sections_clause())
3305 const bool check_sections
= parameters
->options().check_sections();
3306 Output_segment
* last_load_segment
= NULL
;
3308 unsigned int shndx_begin
= *pshndx
;
3309 unsigned int shndx_load_seg
= *pshndx
;
3311 for (Segment_list::iterator p
= this->segment_list_
.begin();
3312 p
!= this->segment_list_
.end();
3315 if ((*p
)->type() == elfcpp::PT_LOAD
)
3317 if (target
->isolate_execinstr())
3319 // When we hit the segment that should contain the
3320 // file headers, reset the file offset so we place
3321 // it and subsequent segments appropriately.
3322 // We'll fix up the preceding segments below.
3330 shndx_load_seg
= *pshndx
;
3336 // Verify that the file headers fall into the first segment.
3337 if (load_seg
!= NULL
&& load_seg
!= *p
)
3342 bool are_addresses_set
= (*p
)->are_addresses_set();
3343 if (are_addresses_set
)
3345 // When it comes to setting file offsets, we care about
3346 // the physical address.
3347 addr
= (*p
)->paddr();
3349 else if (parameters
->options().user_set_Ttext()
3350 && ((*p
)->flags() & elfcpp::PF_W
) == 0)
3352 are_addresses_set
= true;
3354 else if (parameters
->options().user_set_Tdata()
3355 && ((*p
)->flags() & elfcpp::PF_W
) != 0
3356 && (!parameters
->options().user_set_Tbss()
3357 || (*p
)->has_any_data_sections()))
3359 addr
= parameters
->options().Tdata();
3360 are_addresses_set
= true;
3362 else if (parameters
->options().user_set_Tbss()
3363 && ((*p
)->flags() & elfcpp::PF_W
) != 0
3364 && !(*p
)->has_any_data_sections())
3366 addr
= parameters
->options().Tbss();
3367 are_addresses_set
= true;
3370 uint64_t orig_addr
= addr
;
3371 uint64_t orig_off
= off
;
3373 uint64_t aligned_addr
= 0;
3374 uint64_t abi_pagesize
= target
->abi_pagesize();
3375 uint64_t common_pagesize
= target
->common_pagesize();
3377 if (!parameters
->options().nmagic()
3378 && !parameters
->options().omagic())
3379 (*p
)->set_minimum_p_align(abi_pagesize
);
3381 if (!are_addresses_set
)
3383 // Skip the address forward one page, maintaining the same
3384 // position within the page. This lets us store both segments
3385 // overlapping on a single page in the file, but the loader will
3386 // put them on different pages in memory. We will revisit this
3387 // decision once we know the size of the segment.
3389 addr
= align_address(addr
, (*p
)->maximum_alignment());
3390 aligned_addr
= addr
;
3394 // This is the segment that will contain the file
3395 // headers, so its offset will have to be exactly zero.
3396 gold_assert(orig_off
== 0);
3398 // If the target wants a fixed minimum distance from the
3399 // text segment to the read-only segment, move up now.
3400 uint64_t min_addr
= start_addr
+ target
->rosegment_gap();
3401 if (addr
< min_addr
)
3404 // But this is not the first segment! To make its
3405 // address congruent with its offset, that address better
3406 // be aligned to the ABI-mandated page size.
3407 addr
= align_address(addr
, abi_pagesize
);
3408 aligned_addr
= addr
;
3412 if ((addr
& (abi_pagesize
- 1)) != 0)
3413 addr
= addr
+ abi_pagesize
;
3415 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
3419 if (!parameters
->options().nmagic()
3420 && !parameters
->options().omagic())
3421 off
= align_file_offset(off
, addr
, abi_pagesize
);
3424 // This is -N or -n with a section script which prevents
3425 // us from using a load segment. We need to ensure that
3426 // the file offset is aligned to the alignment of the
3427 // segment. This is because the linker script
3428 // implicitly assumed a zero offset. If we don't align
3429 // here, then the alignment of the sections in the
3430 // linker script may not match the alignment of the
3431 // sections in the set_section_addresses call below,
3432 // causing an error about dot moving backward.
3433 off
= align_address(off
, (*p
)->maximum_alignment());
3436 unsigned int shndx_hold
= *pshndx
;
3437 bool has_relro
= false;
3438 uint64_t new_addr
= (*p
)->set_section_addresses(this, false, addr
,
3443 // Now that we know the size of this segment, we may be able
3444 // to save a page in memory, at the cost of wasting some
3445 // file space, by instead aligning to the start of a new
3446 // page. Here we use the real machine page size rather than
3447 // the ABI mandated page size. If the segment has been
3448 // aligned so that the relro data ends at a page boundary,
3449 // we do not try to realign it.
3451 if (!are_addresses_set
3453 && aligned_addr
!= addr
3454 && !parameters
->incremental())
3456 uint64_t first_off
= (common_pagesize
3458 & (common_pagesize
- 1)));
3459 uint64_t last_off
= new_addr
& (common_pagesize
- 1);
3462 && ((aligned_addr
& ~ (common_pagesize
- 1))
3463 != (new_addr
& ~ (common_pagesize
- 1)))
3464 && first_off
+ last_off
<= common_pagesize
)
3466 *pshndx
= shndx_hold
;
3467 addr
= align_address(aligned_addr
, common_pagesize
);
3468 addr
= align_address(addr
, (*p
)->maximum_alignment());
3469 if ((addr
& (abi_pagesize
- 1)) != 0)
3470 addr
= addr
+ abi_pagesize
;
3471 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
3472 off
= align_file_offset(off
, addr
, abi_pagesize
);
3474 increase_relro
= this->increase_relro_
;
3475 if (this->script_options_
->saw_sections_clause())
3479 new_addr
= (*p
)->set_section_addresses(this, true, addr
,
3488 // Implement --check-sections. We know that the segments
3489 // are sorted by LMA.
3490 if (check_sections
&& last_load_segment
!= NULL
)
3492 gold_assert(last_load_segment
->paddr() <= (*p
)->paddr());
3493 if (last_load_segment
->paddr() + last_load_segment
->memsz()
3496 unsigned long long lb1
= last_load_segment
->paddr();
3497 unsigned long long le1
= lb1
+ last_load_segment
->memsz();
3498 unsigned long long lb2
= (*p
)->paddr();
3499 unsigned long long le2
= lb2
+ (*p
)->memsz();
3500 gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
3501 "[0x%llx -> 0x%llx]"),
3502 lb1
, le1
, lb2
, le2
);
3505 last_load_segment
= *p
;
3509 if (load_seg
!= NULL
&& target
->isolate_execinstr())
3511 // Process the early segments again, setting their file offsets
3512 // so they land after the segments starting at LOAD_SEG.
3513 off
= align_file_offset(off
, 0, target
->abi_pagesize());
3515 for (Segment_list::iterator p
= this->segment_list_
.begin();
3519 if ((*p
)->type() == elfcpp::PT_LOAD
)
3521 // We repeat the whole job of assigning addresses and
3522 // offsets, but we really only want to change the offsets and
3523 // must ensure that the addresses all come out the same as
3524 // they did the first time through.
3525 bool has_relro
= false;
3526 const uint64_t old_addr
= (*p
)->vaddr();
3527 const uint64_t old_end
= old_addr
+ (*p
)->memsz();
3528 uint64_t new_addr
= (*p
)->set_section_addresses(this, true,
3534 gold_assert(new_addr
== old_end
);
3538 gold_assert(shndx_begin
== shndx_load_seg
);
3541 // Handle the non-PT_LOAD segments, setting their offsets from their
3542 // section's offsets.
3543 for (Segment_list::iterator p
= this->segment_list_
.begin();
3544 p
!= this->segment_list_
.end();
3547 if ((*p
)->type() != elfcpp::PT_LOAD
)
3548 (*p
)->set_offset((*p
)->type() == elfcpp::PT_GNU_RELRO
3553 // Set the TLS offsets for each section in the PT_TLS segment.
3554 if (this->tls_segment_
!= NULL
)
3555 this->tls_segment_
->set_tls_offsets();
3560 // Set the offsets of all the allocated sections when doing a
3561 // relocatable link. This does the same jobs as set_segment_offsets,
3562 // only for a relocatable link.
3565 Layout::set_relocatable_section_offsets(Output_data
* file_header
,
3566 unsigned int* pshndx
)
3570 file_header
->set_address_and_file_offset(0, 0);
3571 off
+= file_header
->data_size();
3573 for (Section_list::iterator p
= this->section_list_
.begin();
3574 p
!= this->section_list_
.end();
3577 // We skip unallocated sections here, except that group sections
3578 // have to come first.
3579 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) == 0
3580 && (*p
)->type() != elfcpp::SHT_GROUP
)
3583 off
= align_address(off
, (*p
)->addralign());
3585 // The linker script might have set the address.
3586 if (!(*p
)->is_address_valid())
3587 (*p
)->set_address(0);
3588 (*p
)->set_file_offset(off
);
3589 (*p
)->finalize_data_size();
3590 off
+= (*p
)->data_size();
3592 (*p
)->set_out_shndx(*pshndx
);
3599 // Set the file offset of all the sections not associated with a
3603 Layout::set_section_offsets(off_t off
, Layout::Section_offset_pass pass
)
3605 off_t startoff
= off
;
3608 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
3609 p
!= this->unattached_section_list_
.end();
3612 // The symtab section is handled in create_symtab_sections.
3613 if (*p
== this->symtab_section_
)
3616 // If we've already set the data size, don't set it again.
3617 if ((*p
)->is_offset_valid() && (*p
)->is_data_size_valid())
3620 if (pass
== BEFORE_INPUT_SECTIONS_PASS
3621 && (*p
)->requires_postprocessing())
3623 (*p
)->create_postprocessing_buffer();
3624 this->any_postprocessing_sections_
= true;
3627 if (pass
== BEFORE_INPUT_SECTIONS_PASS
3628 && (*p
)->after_input_sections())
3630 else if (pass
== POSTPROCESSING_SECTIONS_PASS
3631 && (!(*p
)->after_input_sections()
3632 || (*p
)->type() == elfcpp::SHT_STRTAB
))
3634 else if (pass
== STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
3635 && (!(*p
)->after_input_sections()
3636 || (*p
)->type() != elfcpp::SHT_STRTAB
))
3639 if (!parameters
->incremental_update())
3641 off
= align_address(off
, (*p
)->addralign());
3642 (*p
)->set_file_offset(off
);
3643 (*p
)->finalize_data_size();
3647 // Incremental update: allocate file space from free list.
3648 (*p
)->pre_finalize_data_size();
3649 off_t current_size
= (*p
)->current_data_size();
3650 off
= this->allocate(current_size
, (*p
)->addralign(), startoff
);
3653 if (is_debugging_enabled(DEBUG_INCREMENTAL
))
3654 this->free_list_
.dump();
3655 gold_assert((*p
)->output_section() != NULL
);
3656 gold_fallback(_("out of patch space for section %s; "
3657 "relink with --incremental-full"),
3658 (*p
)->output_section()->name());
3660 (*p
)->set_file_offset(off
);
3661 (*p
)->finalize_data_size();
3662 if ((*p
)->data_size() > current_size
)
3664 gold_assert((*p
)->output_section() != NULL
);
3665 gold_fallback(_("%s: section changed size; "
3666 "relink with --incremental-full"),
3667 (*p
)->output_section()->name());
3669 gold_debug(DEBUG_INCREMENTAL
,
3670 "set_section_offsets: %08lx %08lx %s",
3671 static_cast<long>(off
),
3672 static_cast<long>((*p
)->data_size()),
3673 ((*p
)->output_section() != NULL
3674 ? (*p
)->output_section()->name() : "(special)"));
3677 off
+= (*p
)->data_size();
3681 // At this point the name must be set.
3682 if (pass
!= STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
)
3683 this->namepool_
.add((*p
)->name(), false, NULL
);
3688 // Set the section indexes of all the sections not associated with a
3692 Layout::set_section_indexes(unsigned int shndx
)
3694 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
3695 p
!= this->unattached_section_list_
.end();
3698 if (!(*p
)->has_out_shndx())
3700 (*p
)->set_out_shndx(shndx
);
3707 // Set the section addresses according to the linker script. This is
3708 // only called when we see a SECTIONS clause. This returns the
3709 // program segment which should hold the file header and segment
3710 // headers, if any. It will return NULL if they should not be in a
3714 Layout::set_section_addresses_from_script(Symbol_table
* symtab
)
3716 Script_sections
* ss
= this->script_options_
->script_sections();
3717 gold_assert(ss
->saw_sections_clause());
3718 return this->script_options_
->set_section_addresses(symtab
, this);
3721 // Place the orphan sections in the linker script.
3724 Layout::place_orphan_sections_in_script()
3726 Script_sections
* ss
= this->script_options_
->script_sections();
3727 gold_assert(ss
->saw_sections_clause());
3729 // Place each orphaned output section in the script.
3730 for (Section_list::iterator p
= this->section_list_
.begin();
3731 p
!= this->section_list_
.end();
3734 if (!(*p
)->found_in_sections_clause())
3735 ss
->place_orphan(*p
);
3739 // Count the local symbols in the regular symbol table and the dynamic
3740 // symbol table, and build the respective string pools.
3743 Layout::count_local_symbols(const Task
* task
,
3744 const Input_objects
* input_objects
)
3746 // First, figure out an upper bound on the number of symbols we'll
3747 // be inserting into each pool. This helps us create the pools with
3748 // the right size, to avoid unnecessary hashtable resizing.
3749 unsigned int symbol_count
= 0;
3750 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3751 p
!= input_objects
->relobj_end();
3753 symbol_count
+= (*p
)->local_symbol_count();
3755 // Go from "upper bound" to "estimate." We overcount for two
3756 // reasons: we double-count symbols that occur in more than one
3757 // object file, and we count symbols that are dropped from the
3758 // output. Add it all together and assume we overcount by 100%.
3761 // We assume all symbols will go into both the sympool and dynpool.
3762 this->sympool_
.reserve(symbol_count
);
3763 this->dynpool_
.reserve(symbol_count
);
3765 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3766 p
!= input_objects
->relobj_end();
3769 Task_lock_obj
<Object
> tlo(task
, *p
);
3770 (*p
)->count_local_symbols(&this->sympool_
, &this->dynpool_
);
3774 // Create the symbol table sections. Here we also set the final
3775 // values of the symbols. At this point all the loadable sections are
3776 // fully laid out. SHNUM is the number of sections so far.
3779 Layout::create_symtab_sections(const Input_objects
* input_objects
,
3780 Symbol_table
* symtab
,
3786 if (parameters
->target().get_size() == 32)
3788 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
3791 else if (parameters
->target().get_size() == 64)
3793 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
3799 // Compute file offsets relative to the start of the symtab section.
3802 // Save space for the dummy symbol at the start of the section. We
3803 // never bother to write this out--it will just be left as zero.
3805 unsigned int local_symbol_index
= 1;
3807 // Add STT_SECTION symbols for each Output section which needs one.
3808 for (Section_list::iterator p
= this->section_list_
.begin();
3809 p
!= this->section_list_
.end();
3812 if (!(*p
)->needs_symtab_index())
3813 (*p
)->set_symtab_index(-1U);
3816 (*p
)->set_symtab_index(local_symbol_index
);
3817 ++local_symbol_index
;
3822 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3823 p
!= input_objects
->relobj_end();
3826 unsigned int index
= (*p
)->finalize_local_symbols(local_symbol_index
,
3828 off
+= (index
- local_symbol_index
) * symsize
;
3829 local_symbol_index
= index
;
3832 unsigned int local_symcount
= local_symbol_index
;
3833 gold_assert(static_cast<off_t
>(local_symcount
* symsize
) == off
);
3836 size_t dyn_global_index
;
3838 if (this->dynsym_section_
== NULL
)
3841 dyn_global_index
= 0;
3846 dyn_global_index
= this->dynsym_section_
->info();
3847 off_t locsize
= dyn_global_index
* this->dynsym_section_
->entsize();
3848 dynoff
= this->dynsym_section_
->offset() + locsize
;
3849 dyncount
= (this->dynsym_section_
->data_size() - locsize
) / symsize
;
3850 gold_assert(static_cast<off_t
>(dyncount
* symsize
)
3851 == this->dynsym_section_
->data_size() - locsize
);
3854 off_t global_off
= off
;
3855 off
= symtab
->finalize(off
, dynoff
, dyn_global_index
, dyncount
,
3856 &this->sympool_
, &local_symcount
);
3858 if (!parameters
->options().strip_all())
3860 this->sympool_
.set_string_offsets();
3862 const char* symtab_name
= this->namepool_
.add(".symtab", false, NULL
);
3863 Output_section
* osymtab
= this->make_output_section(symtab_name
,
3867 this->symtab_section_
= osymtab
;
3869 Output_section_data
* pos
= new Output_data_fixed_space(off
, align
,
3871 osymtab
->add_output_section_data(pos
);
3873 // We generate a .symtab_shndx section if we have more than
3874 // SHN_LORESERVE sections. Technically it is possible that we
3875 // don't need one, because it is possible that there are no
3876 // symbols in any of sections with indexes larger than
3877 // SHN_LORESERVE. That is probably unusual, though, and it is
3878 // easier to always create one than to compute section indexes
3879 // twice (once here, once when writing out the symbols).
3880 if (shnum
>= elfcpp::SHN_LORESERVE
)
3882 const char* symtab_xindex_name
= this->namepool_
.add(".symtab_shndx",
3884 Output_section
* osymtab_xindex
=
3885 this->make_output_section(symtab_xindex_name
,
3886 elfcpp::SHT_SYMTAB_SHNDX
, 0,
3887 ORDER_INVALID
, false);
3889 size_t symcount
= off
/ symsize
;
3890 this->symtab_xindex_
= new Output_symtab_xindex(symcount
);
3892 osymtab_xindex
->add_output_section_data(this->symtab_xindex_
);
3894 osymtab_xindex
->set_link_section(osymtab
);
3895 osymtab_xindex
->set_addralign(4);
3896 osymtab_xindex
->set_entsize(4);
3898 osymtab_xindex
->set_after_input_sections();
3900 // This tells the driver code to wait until the symbol table
3901 // has written out before writing out the postprocessing
3902 // sections, including the .symtab_shndx section.
3903 this->any_postprocessing_sections_
= true;
3906 const char* strtab_name
= this->namepool_
.add(".strtab", false, NULL
);
3907 Output_section
* ostrtab
= this->make_output_section(strtab_name
,
3912 Output_section_data
* pstr
= new Output_data_strtab(&this->sympool_
);
3913 ostrtab
->add_output_section_data(pstr
);
3916 if (!parameters
->incremental_update())
3917 symtab_off
= align_address(*poff
, align
);
3920 symtab_off
= this->allocate(off
, align
, *poff
);
3922 gold_fallback(_("out of patch space for symbol table; "
3923 "relink with --incremental-full"));
3924 gold_debug(DEBUG_INCREMENTAL
,
3925 "create_symtab_sections: %08lx %08lx .symtab",
3926 static_cast<long>(symtab_off
),
3927 static_cast<long>(off
));
3930 symtab
->set_file_offset(symtab_off
+ global_off
);
3931 osymtab
->set_file_offset(symtab_off
);
3932 osymtab
->finalize_data_size();
3933 osymtab
->set_link_section(ostrtab
);
3934 osymtab
->set_info(local_symcount
);
3935 osymtab
->set_entsize(symsize
);
3937 if (symtab_off
+ off
> *poff
)
3938 *poff
= symtab_off
+ off
;
3942 // Create the .shstrtab section, which holds the names of the
3943 // sections. At the time this is called, we have created all the
3944 // output sections except .shstrtab itself.
3947 Layout::create_shstrtab()
3949 // FIXME: We don't need to create a .shstrtab section if we are
3950 // stripping everything.
3952 const char* name
= this->namepool_
.add(".shstrtab", false, NULL
);
3954 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_STRTAB
, 0,
3955 ORDER_INVALID
, false);
3957 if (strcmp(parameters
->options().compress_debug_sections(), "none") != 0)
3959 // We can't write out this section until we've set all the
3960 // section names, and we don't set the names of compressed
3961 // output sections until relocations are complete. FIXME: With
3962 // the current names we use, this is unnecessary.
3963 os
->set_after_input_sections();
3966 Output_section_data
* posd
= new Output_data_strtab(&this->namepool_
);
3967 os
->add_output_section_data(posd
);
3972 // Create the section headers. SIZE is 32 or 64. OFF is the file
3976 Layout::create_shdrs(const Output_section
* shstrtab_section
, off_t
* poff
)
3978 Output_section_headers
* oshdrs
;
3979 oshdrs
= new Output_section_headers(this,
3980 &this->segment_list_
,
3981 &this->section_list_
,
3982 &this->unattached_section_list_
,
3986 if (!parameters
->incremental_update())
3987 off
= align_address(*poff
, oshdrs
->addralign());
3990 oshdrs
->pre_finalize_data_size();
3991 off
= this->allocate(oshdrs
->data_size(), oshdrs
->addralign(), *poff
);
3993 gold_fallback(_("out of patch space for section header table; "
3994 "relink with --incremental-full"));
3995 gold_debug(DEBUG_INCREMENTAL
,
3996 "create_shdrs: %08lx %08lx (section header table)",
3997 static_cast<long>(off
),
3998 static_cast<long>(off
+ oshdrs
->data_size()));
4000 oshdrs
->set_address_and_file_offset(0, off
);
4001 off
+= oshdrs
->data_size();
4004 this->section_headers_
= oshdrs
;
4007 // Count the allocated sections.
4010 Layout::allocated_output_section_count() const
4012 size_t section_count
= 0;
4013 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4014 p
!= this->segment_list_
.end();
4016 section_count
+= (*p
)->output_section_count();
4017 return section_count
;
4020 // Create the dynamic symbol table.
4023 Layout::create_dynamic_symtab(const Input_objects
* input_objects
,
4024 Symbol_table
* symtab
,
4025 Output_section
** pdynstr
,
4026 unsigned int* plocal_dynamic_count
,
4027 std::vector
<Symbol
*>* pdynamic_symbols
,
4028 Versions
* pversions
)
4030 // Count all the symbols in the dynamic symbol table, and set the
4031 // dynamic symbol indexes.
4033 // Skip symbol 0, which is always all zeroes.
4034 unsigned int index
= 1;
4036 // Add STT_SECTION symbols for each Output section which needs one.
4037 for (Section_list::iterator p
= this->section_list_
.begin();
4038 p
!= this->section_list_
.end();
4041 if (!(*p
)->needs_dynsym_index())
4042 (*p
)->set_dynsym_index(-1U);
4045 (*p
)->set_dynsym_index(index
);
4050 // Count the local symbols that need to go in the dynamic symbol table,
4051 // and set the dynamic symbol indexes.
4052 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4053 p
!= input_objects
->relobj_end();
4056 unsigned int new_index
= (*p
)->set_local_dynsym_indexes(index
);
4060 unsigned int local_symcount
= index
;
4061 *plocal_dynamic_count
= local_symcount
;
4063 index
= symtab
->set_dynsym_indexes(index
, pdynamic_symbols
,
4064 &this->dynpool_
, pversions
);
4068 const int size
= parameters
->target().get_size();
4071 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
4074 else if (size
== 64)
4076 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
4082 // Create the dynamic symbol table section.
4084 Output_section
* dynsym
= this->choose_output_section(NULL
, ".dynsym",
4088 ORDER_DYNAMIC_LINKER
,
4091 // Check for NULL as a linker script may discard .dynsym.
4094 Output_section_data
* odata
= new Output_data_fixed_space(index
* symsize
,
4097 dynsym
->add_output_section_data(odata
);
4099 dynsym
->set_info(local_symcount
);
4100 dynsym
->set_entsize(symsize
);
4101 dynsym
->set_addralign(align
);
4103 this->dynsym_section_
= dynsym
;
4106 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4109 odyn
->add_section_address(elfcpp::DT_SYMTAB
, dynsym
);
4110 odyn
->add_constant(elfcpp::DT_SYMENT
, symsize
);
4113 // If there are more than SHN_LORESERVE allocated sections, we
4114 // create a .dynsym_shndx section. It is possible that we don't
4115 // need one, because it is possible that there are no dynamic
4116 // symbols in any of the sections with indexes larger than
4117 // SHN_LORESERVE. This is probably unusual, though, and at this
4118 // time we don't know the actual section indexes so it is
4119 // inconvenient to check.
4120 if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE
)
4122 Output_section
* dynsym_xindex
=
4123 this->choose_output_section(NULL
, ".dynsym_shndx",
4124 elfcpp::SHT_SYMTAB_SHNDX
,
4126 false, ORDER_DYNAMIC_LINKER
, false);
4128 if (dynsym_xindex
!= NULL
)
4130 this->dynsym_xindex_
= new Output_symtab_xindex(index
);
4132 dynsym_xindex
->add_output_section_data(this->dynsym_xindex_
);
4134 dynsym_xindex
->set_link_section(dynsym
);
4135 dynsym_xindex
->set_addralign(4);
4136 dynsym_xindex
->set_entsize(4);
4138 dynsym_xindex
->set_after_input_sections();
4140 // This tells the driver code to wait until the symbol table
4141 // has written out before writing out the postprocessing
4142 // sections, including the .dynsym_shndx section.
4143 this->any_postprocessing_sections_
= true;
4147 // Create the dynamic string table section.
4149 Output_section
* dynstr
= this->choose_output_section(NULL
, ".dynstr",
4153 ORDER_DYNAMIC_LINKER
,
4158 Output_section_data
* strdata
= new Output_data_strtab(&this->dynpool_
);
4159 dynstr
->add_output_section_data(strdata
);
4162 dynsym
->set_link_section(dynstr
);
4163 if (this->dynamic_section_
!= NULL
)
4164 this->dynamic_section_
->set_link_section(dynstr
);
4168 odyn
->add_section_address(elfcpp::DT_STRTAB
, dynstr
);
4169 odyn
->add_section_size(elfcpp::DT_STRSZ
, dynstr
);
4175 // Create the hash tables.
4177 if (strcmp(parameters
->options().hash_style(), "sysv") == 0
4178 || strcmp(parameters
->options().hash_style(), "both") == 0)
4180 unsigned char* phash
;
4181 unsigned int hashlen
;
4182 Dynobj::create_elf_hash_table(*pdynamic_symbols
, local_symcount
,
4185 Output_section
* hashsec
=
4186 this->choose_output_section(NULL
, ".hash", elfcpp::SHT_HASH
,
4187 elfcpp::SHF_ALLOC
, false,
4188 ORDER_DYNAMIC_LINKER
, false);
4190 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
4194 if (hashsec
!= NULL
&& hashdata
!= NULL
)
4195 hashsec
->add_output_section_data(hashdata
);
4197 if (hashsec
!= NULL
)
4200 hashsec
->set_link_section(dynsym
);
4201 hashsec
->set_entsize(4);
4205 odyn
->add_section_address(elfcpp::DT_HASH
, hashsec
);
4208 if (strcmp(parameters
->options().hash_style(), "gnu") == 0
4209 || strcmp(parameters
->options().hash_style(), "both") == 0)
4211 unsigned char* phash
;
4212 unsigned int hashlen
;
4213 Dynobj::create_gnu_hash_table(*pdynamic_symbols
, local_symcount
,
4216 Output_section
* hashsec
=
4217 this->choose_output_section(NULL
, ".gnu.hash", elfcpp::SHT_GNU_HASH
,
4218 elfcpp::SHF_ALLOC
, false,
4219 ORDER_DYNAMIC_LINKER
, false);
4221 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
4225 if (hashsec
!= NULL
&& hashdata
!= NULL
)
4226 hashsec
->add_output_section_data(hashdata
);
4228 if (hashsec
!= NULL
)
4231 hashsec
->set_link_section(dynsym
);
4233 // For a 64-bit target, the entries in .gnu.hash do not have
4234 // a uniform size, so we only set the entry size for a
4236 if (parameters
->target().get_size() == 32)
4237 hashsec
->set_entsize(4);
4240 odyn
->add_section_address(elfcpp::DT_GNU_HASH
, hashsec
);
4245 // Assign offsets to each local portion of the dynamic symbol table.
4248 Layout::assign_local_dynsym_offsets(const Input_objects
* input_objects
)
4250 Output_section
* dynsym
= this->dynsym_section_
;
4254 off_t off
= dynsym
->offset();
4256 // Skip the dummy symbol at the start of the section.
4257 off
+= dynsym
->entsize();
4259 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4260 p
!= input_objects
->relobj_end();
4263 unsigned int count
= (*p
)->set_local_dynsym_offset(off
);
4264 off
+= count
* dynsym
->entsize();
4268 // Create the version sections.
4271 Layout::create_version_sections(const Versions
* versions
,
4272 const Symbol_table
* symtab
,
4273 unsigned int local_symcount
,
4274 const std::vector
<Symbol
*>& dynamic_symbols
,
4275 const Output_section
* dynstr
)
4277 if (!versions
->any_defs() && !versions
->any_needs())
4280 switch (parameters
->size_and_endianness())
4282 #ifdef HAVE_TARGET_32_LITTLE
4283 case Parameters::TARGET_32_LITTLE
:
4284 this->sized_create_version_sections
<32, false>(versions
, symtab
,
4286 dynamic_symbols
, dynstr
);
4289 #ifdef HAVE_TARGET_32_BIG
4290 case Parameters::TARGET_32_BIG
:
4291 this->sized_create_version_sections
<32, true>(versions
, symtab
,
4293 dynamic_symbols
, dynstr
);
4296 #ifdef HAVE_TARGET_64_LITTLE
4297 case Parameters::TARGET_64_LITTLE
:
4298 this->sized_create_version_sections
<64, false>(versions
, symtab
,
4300 dynamic_symbols
, dynstr
);
4303 #ifdef HAVE_TARGET_64_BIG
4304 case Parameters::TARGET_64_BIG
:
4305 this->sized_create_version_sections
<64, true>(versions
, symtab
,
4307 dynamic_symbols
, dynstr
);
4315 // Create the version sections, sized version.
4317 template<int size
, bool big_endian
>
4319 Layout::sized_create_version_sections(
4320 const Versions
* versions
,
4321 const Symbol_table
* symtab
,
4322 unsigned int local_symcount
,
4323 const std::vector
<Symbol
*>& dynamic_symbols
,
4324 const Output_section
* dynstr
)
4326 Output_section
* vsec
= this->choose_output_section(NULL
, ".gnu.version",
4327 elfcpp::SHT_GNU_versym
,
4330 ORDER_DYNAMIC_LINKER
,
4333 // Check for NULL since a linker script may discard this section.
4336 unsigned char* vbuf
;
4338 versions
->symbol_section_contents
<size
, big_endian
>(symtab
,
4344 Output_section_data
* vdata
= new Output_data_const_buffer(vbuf
, vsize
, 2,
4347 vsec
->add_output_section_data(vdata
);
4348 vsec
->set_entsize(2);
4349 vsec
->set_link_section(this->dynsym_section_
);
4352 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4353 if (odyn
!= NULL
&& vsec
!= NULL
)
4354 odyn
->add_section_address(elfcpp::DT_VERSYM
, vsec
);
4356 if (versions
->any_defs())
4358 Output_section
* vdsec
;
4359 vdsec
= this->choose_output_section(NULL
, ".gnu.version_d",
4360 elfcpp::SHT_GNU_verdef
,
4362 false, ORDER_DYNAMIC_LINKER
, false);
4366 unsigned char* vdbuf
;
4367 unsigned int vdsize
;
4368 unsigned int vdentries
;
4369 versions
->def_section_contents
<size
, big_endian
>(&this->dynpool_
,
4373 Output_section_data
* vddata
=
4374 new Output_data_const_buffer(vdbuf
, vdsize
, 4, "** version defs");
4376 vdsec
->add_output_section_data(vddata
);
4377 vdsec
->set_link_section(dynstr
);
4378 vdsec
->set_info(vdentries
);
4382 odyn
->add_section_address(elfcpp::DT_VERDEF
, vdsec
);
4383 odyn
->add_constant(elfcpp::DT_VERDEFNUM
, vdentries
);
4388 if (versions
->any_needs())
4390 Output_section
* vnsec
;
4391 vnsec
= this->choose_output_section(NULL
, ".gnu.version_r",
4392 elfcpp::SHT_GNU_verneed
,
4394 false, ORDER_DYNAMIC_LINKER
, false);
4398 unsigned char* vnbuf
;
4399 unsigned int vnsize
;
4400 unsigned int vnentries
;
4401 versions
->need_section_contents
<size
, big_endian
>(&this->dynpool_
,
4405 Output_section_data
* vndata
=
4406 new Output_data_const_buffer(vnbuf
, vnsize
, 4, "** version refs");
4408 vnsec
->add_output_section_data(vndata
);
4409 vnsec
->set_link_section(dynstr
);
4410 vnsec
->set_info(vnentries
);
4414 odyn
->add_section_address(elfcpp::DT_VERNEED
, vnsec
);
4415 odyn
->add_constant(elfcpp::DT_VERNEEDNUM
, vnentries
);
4421 // Create the .interp section and PT_INTERP segment.
4424 Layout::create_interp(const Target
* target
)
4426 gold_assert(this->interp_segment_
== NULL
);
4428 const char* interp
= parameters
->options().dynamic_linker();
4431 interp
= target
->dynamic_linker();
4432 gold_assert(interp
!= NULL
);
4435 size_t len
= strlen(interp
) + 1;
4437 Output_section_data
* odata
= new Output_data_const(interp
, len
, 1);
4439 Output_section
* osec
= this->choose_output_section(NULL
, ".interp",
4440 elfcpp::SHT_PROGBITS
,
4442 false, ORDER_INTERP
,
4445 osec
->add_output_section_data(odata
);
4448 // Add dynamic tags for the PLT and the dynamic relocs. This is
4449 // called by the target-specific code. This does nothing if not doing
4452 // USE_REL is true for REL relocs rather than RELA relocs.
4454 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
4456 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
4457 // and we also set DT_PLTREL. We use PLT_REL's output section, since
4458 // some targets have multiple reloc sections in PLT_REL.
4460 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
4461 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT. Again we use the output
4464 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
4468 Layout::add_target_dynamic_tags(bool use_rel
, const Output_data
* plt_got
,
4469 const Output_data
* plt_rel
,
4470 const Output_data_reloc_generic
* dyn_rel
,
4471 bool add_debug
, bool dynrel_includes_plt
)
4473 Output_data_dynamic
* odyn
= this->dynamic_data_
;
4477 if (plt_got
!= NULL
&& plt_got
->output_section() != NULL
)
4478 odyn
->add_section_address(elfcpp::DT_PLTGOT
, plt_got
);
4480 if (plt_rel
!= NULL
&& plt_rel
->output_section() != NULL
)
4482 odyn
->add_section_size(elfcpp::DT_PLTRELSZ
, plt_rel
->output_section());
4483 odyn
->add_section_address(elfcpp::DT_JMPREL
, plt_rel
->output_section());
4484 odyn
->add_constant(elfcpp::DT_PLTREL
,
4485 use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
);
4488 if ((dyn_rel
!= NULL
&& dyn_rel
->output_section() != NULL
)
4489 || (dynrel_includes_plt
4491 && plt_rel
->output_section() != NULL
))
4493 bool have_dyn_rel
= dyn_rel
!= NULL
&& dyn_rel
->output_section() != NULL
;
4494 bool have_plt_rel
= plt_rel
!= NULL
&& plt_rel
->output_section() != NULL
;
4495 odyn
->add_section_address(use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
,
4497 ? dyn_rel
->output_section()
4498 : plt_rel
->output_section()));
4499 elfcpp::DT size_tag
= use_rel
? elfcpp::DT_RELSZ
: elfcpp::DT_RELASZ
;
4500 if (have_dyn_rel
&& have_plt_rel
&& dynrel_includes_plt
)
4501 odyn
->add_section_size(size_tag
,
4502 dyn_rel
->output_section(),
4503 plt_rel
->output_section());
4504 else if (have_dyn_rel
)
4505 odyn
->add_section_size(size_tag
, dyn_rel
->output_section());
4507 odyn
->add_section_size(size_tag
, plt_rel
->output_section());
4508 const int size
= parameters
->target().get_size();
4513 rel_tag
= elfcpp::DT_RELENT
;
4515 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 32, false>::reloc_size
;
4516 else if (size
== 64)
4517 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 64, false>::reloc_size
;
4523 rel_tag
= elfcpp::DT_RELAENT
;
4525 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 32, false>::reloc_size
;
4526 else if (size
== 64)
4527 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 64, false>::reloc_size
;
4531 odyn
->add_constant(rel_tag
, rel_size
);
4533 if (parameters
->options().combreloc() && have_dyn_rel
)
4535 size_t c
= dyn_rel
->relative_reloc_count();
4537 odyn
->add_constant((use_rel
4538 ? elfcpp::DT_RELCOUNT
4539 : elfcpp::DT_RELACOUNT
),
4544 if (add_debug
&& !parameters
->options().shared())
4546 // The value of the DT_DEBUG tag is filled in by the dynamic
4547 // linker at run time, and used by the debugger.
4548 odyn
->add_constant(elfcpp::DT_DEBUG
, 0);
4552 // Finish the .dynamic section and PT_DYNAMIC segment.
4555 Layout::finish_dynamic_section(const Input_objects
* input_objects
,
4556 const Symbol_table
* symtab
)
4558 if (!this->script_options_
->saw_phdrs_clause()
4559 && this->dynamic_section_
!= NULL
)
4561 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_DYNAMIC
,
4564 oseg
->add_output_section_to_nonload(this->dynamic_section_
,
4565 elfcpp::PF_R
| elfcpp::PF_W
);
4568 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4572 for (Input_objects::Dynobj_iterator p
= input_objects
->dynobj_begin();
4573 p
!= input_objects
->dynobj_end();
4576 if (!(*p
)->is_needed() && (*p
)->as_needed())
4578 // This dynamic object was linked with --as-needed, but it
4583 odyn
->add_string(elfcpp::DT_NEEDED
, (*p
)->soname());
4586 if (parameters
->options().shared())
4588 const char* soname
= parameters
->options().soname();
4590 odyn
->add_string(elfcpp::DT_SONAME
, soname
);
4593 Symbol
* sym
= symtab
->lookup(parameters
->options().init());
4594 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
4595 odyn
->add_symbol(elfcpp::DT_INIT
, sym
);
4597 sym
= symtab
->lookup(parameters
->options().fini());
4598 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
4599 odyn
->add_symbol(elfcpp::DT_FINI
, sym
);
4601 // Look for .init_array, .preinit_array and .fini_array by checking
4603 for(Layout::Section_list::const_iterator p
= this->section_list_
.begin();
4604 p
!= this->section_list_
.end();
4606 switch((*p
)->type())
4608 case elfcpp::SHT_FINI_ARRAY
:
4609 odyn
->add_section_address(elfcpp::DT_FINI_ARRAY
, *p
);
4610 odyn
->add_section_size(elfcpp::DT_FINI_ARRAYSZ
, *p
);
4612 case elfcpp::SHT_INIT_ARRAY
:
4613 odyn
->add_section_address(elfcpp::DT_INIT_ARRAY
, *p
);
4614 odyn
->add_section_size(elfcpp::DT_INIT_ARRAYSZ
, *p
);
4616 case elfcpp::SHT_PREINIT_ARRAY
:
4617 odyn
->add_section_address(elfcpp::DT_PREINIT_ARRAY
, *p
);
4618 odyn
->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ
, *p
);
4624 // Add a DT_RPATH entry if needed.
4625 const General_options::Dir_list
& rpath(parameters
->options().rpath());
4628 std::string rpath_val
;
4629 for (General_options::Dir_list::const_iterator p
= rpath
.begin();
4633 if (rpath_val
.empty())
4634 rpath_val
= p
->name();
4637 // Eliminate duplicates.
4638 General_options::Dir_list::const_iterator q
;
4639 for (q
= rpath
.begin(); q
!= p
; ++q
)
4640 if (q
->name() == p
->name())
4645 rpath_val
+= p
->name();
4650 if (!parameters
->options().enable_new_dtags())
4651 odyn
->add_string(elfcpp::DT_RPATH
, rpath_val
);
4653 odyn
->add_string(elfcpp::DT_RUNPATH
, rpath_val
);
4656 // Look for text segments that have dynamic relocations.
4657 bool have_textrel
= false;
4658 if (!this->script_options_
->saw_sections_clause())
4660 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4661 p
!= this->segment_list_
.end();
4664 if ((*p
)->type() == elfcpp::PT_LOAD
4665 && ((*p
)->flags() & elfcpp::PF_W
) == 0
4666 && (*p
)->has_dynamic_reloc())
4668 have_textrel
= true;
4675 // We don't know the section -> segment mapping, so we are
4676 // conservative and just look for readonly sections with
4677 // relocations. If those sections wind up in writable segments,
4678 // then we have created an unnecessary DT_TEXTREL entry.
4679 for (Section_list::const_iterator p
= this->section_list_
.begin();
4680 p
!= this->section_list_
.end();
4683 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0
4684 && ((*p
)->flags() & elfcpp::SHF_WRITE
) == 0
4685 && (*p
)->has_dynamic_reloc())
4687 have_textrel
= true;
4693 if (parameters
->options().filter() != NULL
)
4694 odyn
->add_string(elfcpp::DT_FILTER
, parameters
->options().filter());
4695 if (parameters
->options().any_auxiliary())
4697 for (options::String_set::const_iterator p
=
4698 parameters
->options().auxiliary_begin();
4699 p
!= parameters
->options().auxiliary_end();
4701 odyn
->add_string(elfcpp::DT_AUXILIARY
, *p
);
4704 // Add a DT_FLAGS entry if necessary.
4705 unsigned int flags
= 0;
4708 // Add a DT_TEXTREL for compatibility with older loaders.
4709 odyn
->add_constant(elfcpp::DT_TEXTREL
, 0);
4710 flags
|= elfcpp::DF_TEXTREL
;
4712 if (parameters
->options().text())
4713 gold_error(_("read-only segment has dynamic relocations"));
4714 else if (parameters
->options().warn_shared_textrel()
4715 && parameters
->options().shared())
4716 gold_warning(_("shared library text segment is not shareable"));
4718 if (parameters
->options().shared() && this->has_static_tls())
4719 flags
|= elfcpp::DF_STATIC_TLS
;
4720 if (parameters
->options().origin())
4721 flags
|= elfcpp::DF_ORIGIN
;
4722 if (parameters
->options().Bsymbolic())
4724 flags
|= elfcpp::DF_SYMBOLIC
;
4725 // Add DT_SYMBOLIC for compatibility with older loaders.
4726 odyn
->add_constant(elfcpp::DT_SYMBOLIC
, 0);
4728 if (parameters
->options().now())
4729 flags
|= elfcpp::DF_BIND_NOW
;
4731 odyn
->add_constant(elfcpp::DT_FLAGS
, flags
);
4734 if (parameters
->options().initfirst())
4735 flags
|= elfcpp::DF_1_INITFIRST
;
4736 if (parameters
->options().interpose())
4737 flags
|= elfcpp::DF_1_INTERPOSE
;
4738 if (parameters
->options().loadfltr())
4739 flags
|= elfcpp::DF_1_LOADFLTR
;
4740 if (parameters
->options().nodefaultlib())
4741 flags
|= elfcpp::DF_1_NODEFLIB
;
4742 if (parameters
->options().nodelete())
4743 flags
|= elfcpp::DF_1_NODELETE
;
4744 if (parameters
->options().nodlopen())
4745 flags
|= elfcpp::DF_1_NOOPEN
;
4746 if (parameters
->options().nodump())
4747 flags
|= elfcpp::DF_1_NODUMP
;
4748 if (!parameters
->options().shared())
4749 flags
&= ~(elfcpp::DF_1_INITFIRST
4750 | elfcpp::DF_1_NODELETE
4751 | elfcpp::DF_1_NOOPEN
);
4752 if (parameters
->options().origin())
4753 flags
|= elfcpp::DF_1_ORIGIN
;
4754 if (parameters
->options().now())
4755 flags
|= elfcpp::DF_1_NOW
;
4756 if (parameters
->options().Bgroup())
4757 flags
|= elfcpp::DF_1_GROUP
;
4759 odyn
->add_constant(elfcpp::DT_FLAGS_1
, flags
);
4762 // Set the size of the _DYNAMIC symbol table to be the size of the
4766 Layout::set_dynamic_symbol_size(const Symbol_table
* symtab
)
4768 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4771 odyn
->finalize_data_size();
4772 if (this->dynamic_symbol_
== NULL
)
4774 off_t data_size
= odyn
->data_size();
4775 const int size
= parameters
->target().get_size();
4777 symtab
->get_sized_symbol
<32>(this->dynamic_symbol_
)->set_symsize(data_size
);
4778 else if (size
== 64)
4779 symtab
->get_sized_symbol
<64>(this->dynamic_symbol_
)->set_symsize(data_size
);
4784 // The mapping of input section name prefixes to output section names.
4785 // In some cases one prefix is itself a prefix of another prefix; in
4786 // such a case the longer prefix must come first. These prefixes are
4787 // based on the GNU linker default ELF linker script.
4789 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
4790 #define MAPPING_INIT_EXACT(f, t) { f, 0, t, sizeof(t) - 1 }
4791 const Layout::Section_name_mapping
Layout::section_name_mapping
[] =
4793 MAPPING_INIT(".text.", ".text"),
4794 MAPPING_INIT(".rodata.", ".rodata"),
4795 MAPPING_INIT(".data.rel.ro.local.", ".data.rel.ro.local"),
4796 MAPPING_INIT_EXACT(".data.rel.ro.local", ".data.rel.ro.local"),
4797 MAPPING_INIT(".data.rel.ro.", ".data.rel.ro"),
4798 MAPPING_INIT_EXACT(".data.rel.ro", ".data.rel.ro"),
4799 MAPPING_INIT(".data.", ".data"),
4800 MAPPING_INIT(".bss.", ".bss"),
4801 MAPPING_INIT(".tdata.", ".tdata"),
4802 MAPPING_INIT(".tbss.", ".tbss"),
4803 MAPPING_INIT(".init_array.", ".init_array"),
4804 MAPPING_INIT(".fini_array.", ".fini_array"),
4805 MAPPING_INIT(".sdata.", ".sdata"),
4806 MAPPING_INIT(".sbss.", ".sbss"),
4807 // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
4808 // differently depending on whether it is creating a shared library.
4809 MAPPING_INIT(".sdata2.", ".sdata"),
4810 MAPPING_INIT(".sbss2.", ".sbss"),
4811 MAPPING_INIT(".lrodata.", ".lrodata"),
4812 MAPPING_INIT(".ldata.", ".ldata"),
4813 MAPPING_INIT(".lbss.", ".lbss"),
4814 MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
4815 MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
4816 MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
4817 MAPPING_INIT(".gnu.linkonce.t.", ".text"),
4818 MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
4819 MAPPING_INIT(".gnu.linkonce.d.", ".data"),
4820 MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
4821 MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
4822 MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
4823 MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
4824 MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
4825 MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
4826 MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
4827 MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
4828 MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
4829 MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
4830 MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
4831 MAPPING_INIT(".ARM.extab", ".ARM.extab"),
4832 MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
4833 MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
4834 MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
4837 #undef MAPPING_INIT_EXACT
4839 const int Layout::section_name_mapping_count
=
4840 (sizeof(Layout::section_name_mapping
)
4841 / sizeof(Layout::section_name_mapping
[0]));
4843 // Choose the output section name to use given an input section name.
4844 // Set *PLEN to the length of the name. *PLEN is initialized to the
4848 Layout::output_section_name(const Relobj
* relobj
, const char* name
,
4851 // gcc 4.3 generates the following sorts of section names when it
4852 // needs a section name specific to a function:
4858 // .data.rel.local.FN
4860 // .data.rel.ro.local.FN
4867 // The GNU linker maps all of those to the part before the .FN,
4868 // except that .data.rel.local.FN is mapped to .data, and
4869 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
4870 // beginning with .data.rel.ro.local are grouped together.
4872 // For an anonymous namespace, the string FN can contain a '.'.
4874 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
4875 // GNU linker maps to .rodata.
4877 // The .data.rel.ro sections are used with -z relro. The sections
4878 // are recognized by name. We use the same names that the GNU
4879 // linker does for these sections.
4881 // It is hard to handle this in a principled way, so we don't even
4882 // try. We use a table of mappings. If the input section name is
4883 // not found in the table, we simply use it as the output section
4886 const Section_name_mapping
* psnm
= section_name_mapping
;
4887 for (int i
= 0; i
< section_name_mapping_count
; ++i
, ++psnm
)
4889 if (psnm
->fromlen
> 0)
4891 if (strncmp(name
, psnm
->from
, psnm
->fromlen
) == 0)
4893 *plen
= psnm
->tolen
;
4899 if (strcmp(name
, psnm
->from
) == 0)
4901 *plen
= psnm
->tolen
;
4907 // As an additional complication, .ctors sections are output in
4908 // either .ctors or .init_array sections, and .dtors sections are
4909 // output in either .dtors or .fini_array sections.
4910 if (is_prefix_of(".ctors.", name
) || is_prefix_of(".dtors.", name
))
4912 if (parameters
->options().ctors_in_init_array())
4915 return name
[1] == 'c' ? ".init_array" : ".fini_array";
4920 return name
[1] == 'c' ? ".ctors" : ".dtors";
4923 if (parameters
->options().ctors_in_init_array()
4924 && (strcmp(name
, ".ctors") == 0 || strcmp(name
, ".dtors") == 0))
4926 // To make .init_array/.fini_array work with gcc we must exclude
4927 // .ctors and .dtors sections from the crtbegin and crtend
4930 || (!Layout::match_file_name(relobj
, "crtbegin")
4931 && !Layout::match_file_name(relobj
, "crtend")))
4934 return name
[1] == 'c' ? ".init_array" : ".fini_array";
4941 // Return true if RELOBJ is an input file whose base name matches
4942 // FILE_NAME. The base name must have an extension of ".o", and must
4943 // be exactly FILE_NAME.o or FILE_NAME, one character, ".o". This is
4944 // to match crtbegin.o as well as crtbeginS.o without getting confused
4945 // by other possibilities. Overall matching the file name this way is
4946 // a dreadful hack, but the GNU linker does it in order to better
4947 // support gcc, and we need to be compatible.
4950 Layout::match_file_name(const Relobj
* relobj
, const char* match
)
4952 const std::string
& file_name(relobj
->name());
4953 const char* base_name
= lbasename(file_name
.c_str());
4954 size_t match_len
= strlen(match
);
4955 if (strncmp(base_name
, match
, match_len
) != 0)
4957 size_t base_len
= strlen(base_name
);
4958 if (base_len
!= match_len
+ 2 && base_len
!= match_len
+ 3)
4960 return memcmp(base_name
+ base_len
- 2, ".o", 2) == 0;
4963 // Check if a comdat group or .gnu.linkonce section with the given
4964 // NAME is selected for the link. If there is already a section,
4965 // *KEPT_SECTION is set to point to the existing section and the
4966 // function returns false. Otherwise, OBJECT, SHNDX, IS_COMDAT, and
4967 // IS_GROUP_NAME are recorded for this NAME in the layout object,
4968 // *KEPT_SECTION is set to the internal copy and the function returns
4972 Layout::find_or_add_kept_section(const std::string
& name
,
4977 Kept_section
** kept_section
)
4979 // It's normal to see a couple of entries here, for the x86 thunk
4980 // sections. If we see more than a few, we're linking a C++
4981 // program, and we resize to get more space to minimize rehashing.
4982 if (this->signatures_
.size() > 4
4983 && !this->resized_signatures_
)
4985 reserve_unordered_map(&this->signatures_
,
4986 this->number_of_input_files_
* 64);
4987 this->resized_signatures_
= true;
4990 Kept_section candidate
;
4991 std::pair
<Signatures::iterator
, bool> ins
=
4992 this->signatures_
.insert(std::make_pair(name
, candidate
));
4994 if (kept_section
!= NULL
)
4995 *kept_section
= &ins
.first
->second
;
4998 // This is the first time we've seen this signature.
4999 ins
.first
->second
.set_object(object
);
5000 ins
.first
->second
.set_shndx(shndx
);
5002 ins
.first
->second
.set_is_comdat();
5004 ins
.first
->second
.set_is_group_name();
5008 // We have already seen this signature.
5010 if (ins
.first
->second
.is_group_name())
5012 // We've already seen a real section group with this signature.
5013 // If the kept group is from a plugin object, and we're in the
5014 // replacement phase, accept the new one as a replacement.
5015 if (ins
.first
->second
.object() == NULL
5016 && parameters
->options().plugins()->in_replacement_phase())
5018 ins
.first
->second
.set_object(object
);
5019 ins
.first
->second
.set_shndx(shndx
);
5024 else if (is_group_name
)
5026 // This is a real section group, and we've already seen a
5027 // linkonce section with this signature. Record that we've seen
5028 // a section group, and don't include this section group.
5029 ins
.first
->second
.set_is_group_name();
5034 // We've already seen a linkonce section and this is a linkonce
5035 // section. These don't block each other--this may be the same
5036 // symbol name with different section types.
5041 // Store the allocated sections into the section list.
5044 Layout::get_allocated_sections(Section_list
* section_list
) const
5046 for (Section_list::const_iterator p
= this->section_list_
.begin();
5047 p
!= this->section_list_
.end();
5049 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0)
5050 section_list
->push_back(*p
);
5053 // Store the executable sections into the section list.
5056 Layout::get_executable_sections(Section_list
* section_list
) const
5058 for (Section_list::const_iterator p
= this->section_list_
.begin();
5059 p
!= this->section_list_
.end();
5061 if (((*p
)->flags() & (elfcpp::SHF_ALLOC
| elfcpp::SHF_EXECINSTR
))
5062 == (elfcpp::SHF_ALLOC
| elfcpp::SHF_EXECINSTR
))
5063 section_list
->push_back(*p
);
5066 // Create an output segment.
5069 Layout::make_output_segment(elfcpp::Elf_Word type
, elfcpp::Elf_Word flags
)
5071 gold_assert(!parameters
->options().relocatable());
5072 Output_segment
* oseg
= new Output_segment(type
, flags
);
5073 this->segment_list_
.push_back(oseg
);
5075 if (type
== elfcpp::PT_TLS
)
5076 this->tls_segment_
= oseg
;
5077 else if (type
== elfcpp::PT_GNU_RELRO
)
5078 this->relro_segment_
= oseg
;
5079 else if (type
== elfcpp::PT_INTERP
)
5080 this->interp_segment_
= oseg
;
5085 // Return the file offset of the normal symbol table.
5088 Layout::symtab_section_offset() const
5090 if (this->symtab_section_
!= NULL
)
5091 return this->symtab_section_
->offset();
5095 // Return the section index of the normal symbol table. It may have
5096 // been stripped by the -s/--strip-all option.
5099 Layout::symtab_section_shndx() const
5101 if (this->symtab_section_
!= NULL
)
5102 return this->symtab_section_
->out_shndx();
5106 // Write out the Output_sections. Most won't have anything to write,
5107 // since most of the data will come from input sections which are
5108 // handled elsewhere. But some Output_sections do have Output_data.
5111 Layout::write_output_sections(Output_file
* of
) const
5113 for (Section_list::const_iterator p
= this->section_list_
.begin();
5114 p
!= this->section_list_
.end();
5117 if (!(*p
)->after_input_sections())
5122 // Write out data not associated with a section or the symbol table.
5125 Layout::write_data(const Symbol_table
* symtab
, Output_file
* of
) const
5127 if (!parameters
->options().strip_all())
5129 const Output_section
* symtab_section
= this->symtab_section_
;
5130 for (Section_list::const_iterator p
= this->section_list_
.begin();
5131 p
!= this->section_list_
.end();
5134 if ((*p
)->needs_symtab_index())
5136 gold_assert(symtab_section
!= NULL
);
5137 unsigned int index
= (*p
)->symtab_index();
5138 gold_assert(index
> 0 && index
!= -1U);
5139 off_t off
= (symtab_section
->offset()
5140 + index
* symtab_section
->entsize());
5141 symtab
->write_section_symbol(*p
, this->symtab_xindex_
, of
, off
);
5146 const Output_section
* dynsym_section
= this->dynsym_section_
;
5147 for (Section_list::const_iterator p
= this->section_list_
.begin();
5148 p
!= this->section_list_
.end();
5151 if ((*p
)->needs_dynsym_index())
5153 gold_assert(dynsym_section
!= NULL
);
5154 unsigned int index
= (*p
)->dynsym_index();
5155 gold_assert(index
> 0 && index
!= -1U);
5156 off_t off
= (dynsym_section
->offset()
5157 + index
* dynsym_section
->entsize());
5158 symtab
->write_section_symbol(*p
, this->dynsym_xindex_
, of
, off
);
5162 // Write out the Output_data which are not in an Output_section.
5163 for (Data_list::const_iterator p
= this->special_output_list_
.begin();
5164 p
!= this->special_output_list_
.end();
5169 // Write out the Output_sections which can only be written after the
5170 // input sections are complete.
5173 Layout::write_sections_after_input_sections(Output_file
* of
)
5175 // Determine the final section offsets, and thus the final output
5176 // file size. Note we finalize the .shstrab last, to allow the
5177 // after_input_section sections to modify their section-names before
5179 if (this->any_postprocessing_sections_
)
5181 off_t off
= this->output_file_size_
;
5182 off
= this->set_section_offsets(off
, POSTPROCESSING_SECTIONS_PASS
);
5184 // Now that we've finalized the names, we can finalize the shstrab.
5186 this->set_section_offsets(off
,
5187 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
5189 if (off
> this->output_file_size_
)
5192 this->output_file_size_
= off
;
5196 for (Section_list::const_iterator p
= this->section_list_
.begin();
5197 p
!= this->section_list_
.end();
5200 if ((*p
)->after_input_sections())
5204 this->section_headers_
->write(of
);
5207 // If the build ID requires computing a checksum, do so here, and
5208 // write it out. We compute a checksum over the entire file because
5209 // that is simplest.
5212 Layout::write_build_id(Output_file
* of
) const
5214 if (this->build_id_note_
== NULL
)
5217 const unsigned char* iv
= of
->get_input_view(0, this->output_file_size_
);
5219 unsigned char* ov
= of
->get_output_view(this->build_id_note_
->offset(),
5220 this->build_id_note_
->data_size());
5222 const char* style
= parameters
->options().build_id();
5223 if (strcmp(style
, "sha1") == 0)
5226 sha1_init_ctx(&ctx
);
5227 sha1_process_bytes(iv
, this->output_file_size_
, &ctx
);
5228 sha1_finish_ctx(&ctx
, ov
);
5230 else if (strcmp(style
, "md5") == 0)
5234 md5_process_bytes(iv
, this->output_file_size_
, &ctx
);
5235 md5_finish_ctx(&ctx
, ov
);
5240 of
->write_output_view(this->build_id_note_
->offset(),
5241 this->build_id_note_
->data_size(),
5244 of
->free_input_view(0, this->output_file_size_
, iv
);
5247 // Write out a binary file. This is called after the link is
5248 // complete. IN is the temporary output file we used to generate the
5249 // ELF code. We simply walk through the segments, read them from
5250 // their file offset in IN, and write them to their load address in
5251 // the output file. FIXME: with a bit more work, we could support
5252 // S-records and/or Intel hex format here.
5255 Layout::write_binary(Output_file
* in
) const
5257 gold_assert(parameters
->options().oformat_enum()
5258 == General_options::OBJECT_FORMAT_BINARY
);
5260 // Get the size of the binary file.
5261 uint64_t max_load_address
= 0;
5262 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5263 p
!= this->segment_list_
.end();
5266 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
5268 uint64_t max_paddr
= (*p
)->paddr() + (*p
)->filesz();
5269 if (max_paddr
> max_load_address
)
5270 max_load_address
= max_paddr
;
5274 Output_file
out(parameters
->options().output_file_name());
5275 out
.open(max_load_address
);
5277 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5278 p
!= this->segment_list_
.end();
5281 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
5283 const unsigned char* vin
= in
->get_input_view((*p
)->offset(),
5285 unsigned char* vout
= out
.get_output_view((*p
)->paddr(),
5287 memcpy(vout
, vin
, (*p
)->filesz());
5288 out
.write_output_view((*p
)->paddr(), (*p
)->filesz(), vout
);
5289 in
->free_input_view((*p
)->offset(), (*p
)->filesz(), vin
);
5296 // Print the output sections to the map file.
5299 Layout::print_to_mapfile(Mapfile
* mapfile
) const
5301 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5302 p
!= this->segment_list_
.end();
5304 (*p
)->print_sections_to_mapfile(mapfile
);
5307 // Print statistical information to stderr. This is used for --stats.
5310 Layout::print_stats() const
5312 this->namepool_
.print_stats("section name pool");
5313 this->sympool_
.print_stats("output symbol name pool");
5314 this->dynpool_
.print_stats("dynamic name pool");
5316 for (Section_list::const_iterator p
= this->section_list_
.begin();
5317 p
!= this->section_list_
.end();
5319 (*p
)->print_merge_stats();
5322 // Write_sections_task methods.
5324 // We can always run this task.
5327 Write_sections_task::is_runnable()
5332 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
5336 Write_sections_task::locks(Task_locker
* tl
)
5338 tl
->add(this, this->output_sections_blocker_
);
5339 tl
->add(this, this->final_blocker_
);
5342 // Run the task--write out the data.
5345 Write_sections_task::run(Workqueue
*)
5347 this->layout_
->write_output_sections(this->of_
);
5350 // Write_data_task methods.
5352 // We can always run this task.
5355 Write_data_task::is_runnable()
5360 // We need to unlock FINAL_BLOCKER when finished.
5363 Write_data_task::locks(Task_locker
* tl
)
5365 tl
->add(this, this->final_blocker_
);
5368 // Run the task--write out the data.
5371 Write_data_task::run(Workqueue
*)
5373 this->layout_
->write_data(this->symtab_
, this->of_
);
5376 // Write_symbols_task methods.
5378 // We can always run this task.
5381 Write_symbols_task::is_runnable()
5386 // We need to unlock FINAL_BLOCKER when finished.
5389 Write_symbols_task::locks(Task_locker
* tl
)
5391 tl
->add(this, this->final_blocker_
);
5394 // Run the task--write out the symbols.
5397 Write_symbols_task::run(Workqueue
*)
5399 this->symtab_
->write_globals(this->sympool_
, this->dynpool_
,
5400 this->layout_
->symtab_xindex(),
5401 this->layout_
->dynsym_xindex(), this->of_
);
5404 // Write_after_input_sections_task methods.
5406 // We can only run this task after the input sections have completed.
5409 Write_after_input_sections_task::is_runnable()
5411 if (this->input_sections_blocker_
->is_blocked())
5412 return this->input_sections_blocker_
;
5416 // We need to unlock FINAL_BLOCKER when finished.
5419 Write_after_input_sections_task::locks(Task_locker
* tl
)
5421 tl
->add(this, this->final_blocker_
);
5427 Write_after_input_sections_task::run(Workqueue
*)
5429 this->layout_
->write_sections_after_input_sections(this->of_
);
5432 // Close_task_runner methods.
5434 // Run the task--close the file.
5437 Close_task_runner::run(Workqueue
*, const Task
*)
5439 // If we need to compute a checksum for the BUILD if, we do so here.
5440 this->layout_
->write_build_id(this->of_
);
5442 // If we've been asked to create a binary file, we do so here.
5443 if (this->options_
->oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
5444 this->layout_
->write_binary(this->of_
);
5449 // Instantiate the templates we need. We could use the configure
5450 // script to restrict this to only the ones for implemented targets.
5452 #ifdef HAVE_TARGET_32_LITTLE
5455 Layout::init_fixed_output_section
<32, false>(
5457 elfcpp::Shdr
<32, false>& shdr
);
5460 #ifdef HAVE_TARGET_32_BIG
5463 Layout::init_fixed_output_section
<32, true>(
5465 elfcpp::Shdr
<32, true>& shdr
);
5468 #ifdef HAVE_TARGET_64_LITTLE
5471 Layout::init_fixed_output_section
<64, false>(
5473 elfcpp::Shdr
<64, false>& shdr
);
5476 #ifdef HAVE_TARGET_64_BIG
5479 Layout::init_fixed_output_section
<64, true>(
5481 elfcpp::Shdr
<64, true>& shdr
);
5484 #ifdef HAVE_TARGET_32_LITTLE
5487 Layout::layout
<32, false>(Sized_relobj_file
<32, false>* object
,
5490 const elfcpp::Shdr
<32, false>& shdr
,
5491 unsigned int, unsigned int, off_t
*);
5494 #ifdef HAVE_TARGET_32_BIG
5497 Layout::layout
<32, true>(Sized_relobj_file
<32, true>* object
,
5500 const elfcpp::Shdr
<32, true>& shdr
,
5501 unsigned int, unsigned int, off_t
*);
5504 #ifdef HAVE_TARGET_64_LITTLE
5507 Layout::layout
<64, false>(Sized_relobj_file
<64, false>* object
,
5510 const elfcpp::Shdr
<64, false>& shdr
,
5511 unsigned int, unsigned int, off_t
*);
5514 #ifdef HAVE_TARGET_64_BIG
5517 Layout::layout
<64, true>(Sized_relobj_file
<64, true>* object
,
5520 const elfcpp::Shdr
<64, true>& shdr
,
5521 unsigned int, unsigned int, off_t
*);
5524 #ifdef HAVE_TARGET_32_LITTLE
5527 Layout::layout_reloc
<32, false>(Sized_relobj_file
<32, false>* object
,
5528 unsigned int reloc_shndx
,
5529 const elfcpp::Shdr
<32, false>& shdr
,
5530 Output_section
* data_section
,
5531 Relocatable_relocs
* rr
);
5534 #ifdef HAVE_TARGET_32_BIG
5537 Layout::layout_reloc
<32, true>(Sized_relobj_file
<32, true>* object
,
5538 unsigned int reloc_shndx
,
5539 const elfcpp::Shdr
<32, true>& shdr
,
5540 Output_section
* data_section
,
5541 Relocatable_relocs
* rr
);
5544 #ifdef HAVE_TARGET_64_LITTLE
5547 Layout::layout_reloc
<64, false>(Sized_relobj_file
<64, false>* object
,
5548 unsigned int reloc_shndx
,
5549 const elfcpp::Shdr
<64, false>& shdr
,
5550 Output_section
* data_section
,
5551 Relocatable_relocs
* rr
);
5554 #ifdef HAVE_TARGET_64_BIG
5557 Layout::layout_reloc
<64, true>(Sized_relobj_file
<64, true>* object
,
5558 unsigned int reloc_shndx
,
5559 const elfcpp::Shdr
<64, true>& shdr
,
5560 Output_section
* data_section
,
5561 Relocatable_relocs
* rr
);
5564 #ifdef HAVE_TARGET_32_LITTLE
5567 Layout::layout_group
<32, false>(Symbol_table
* symtab
,
5568 Sized_relobj_file
<32, false>* object
,
5570 const char* group_section_name
,
5571 const char* signature
,
5572 const elfcpp::Shdr
<32, false>& shdr
,
5573 elfcpp::Elf_Word flags
,
5574 std::vector
<unsigned int>* shndxes
);
5577 #ifdef HAVE_TARGET_32_BIG
5580 Layout::layout_group
<32, true>(Symbol_table
* symtab
,
5581 Sized_relobj_file
<32, true>* object
,
5583 const char* group_section_name
,
5584 const char* signature
,
5585 const elfcpp::Shdr
<32, true>& shdr
,
5586 elfcpp::Elf_Word flags
,
5587 std::vector
<unsigned int>* shndxes
);
5590 #ifdef HAVE_TARGET_64_LITTLE
5593 Layout::layout_group
<64, false>(Symbol_table
* symtab
,
5594 Sized_relobj_file
<64, false>* object
,
5596 const char* group_section_name
,
5597 const char* signature
,
5598 const elfcpp::Shdr
<64, false>& shdr
,
5599 elfcpp::Elf_Word flags
,
5600 std::vector
<unsigned int>* shndxes
);
5603 #ifdef HAVE_TARGET_64_BIG
5606 Layout::layout_group
<64, true>(Symbol_table
* symtab
,
5607 Sized_relobj_file
<64, true>* object
,
5609 const char* group_section_name
,
5610 const char* signature
,
5611 const elfcpp::Shdr
<64, true>& shdr
,
5612 elfcpp::Elf_Word flags
,
5613 std::vector
<unsigned int>* shndxes
);
5616 #ifdef HAVE_TARGET_32_LITTLE
5619 Layout::layout_eh_frame
<32, false>(Sized_relobj_file
<32, false>* object
,
5620 const unsigned char* symbols
,
5622 const unsigned char* symbol_names
,
5623 off_t symbol_names_size
,
5625 const elfcpp::Shdr
<32, false>& shdr
,
5626 unsigned int reloc_shndx
,
5627 unsigned int reloc_type
,
5631 #ifdef HAVE_TARGET_32_BIG
5634 Layout::layout_eh_frame
<32, true>(Sized_relobj_file
<32, true>* object
,
5635 const unsigned char* symbols
,
5637 const unsigned char* symbol_names
,
5638 off_t symbol_names_size
,
5640 const elfcpp::Shdr
<32, true>& shdr
,
5641 unsigned int reloc_shndx
,
5642 unsigned int reloc_type
,
5646 #ifdef HAVE_TARGET_64_LITTLE
5649 Layout::layout_eh_frame
<64, false>(Sized_relobj_file
<64, false>* object
,
5650 const unsigned char* symbols
,
5652 const unsigned char* symbol_names
,
5653 off_t symbol_names_size
,
5655 const elfcpp::Shdr
<64, false>& shdr
,
5656 unsigned int reloc_shndx
,
5657 unsigned int reloc_type
,
5661 #ifdef HAVE_TARGET_64_BIG
5664 Layout::layout_eh_frame
<64, true>(Sized_relobj_file
<64, true>* object
,
5665 const unsigned char* symbols
,
5667 const unsigned char* symbol_names
,
5668 off_t symbol_names_size
,
5670 const elfcpp::Shdr
<64, true>& shdr
,
5671 unsigned int reloc_shndx
,
5672 unsigned int reloc_type
,
5676 #ifdef HAVE_TARGET_32_LITTLE
5679 Layout::add_to_gdb_index(bool is_type_unit
,
5680 Sized_relobj
<32, false>* object
,
5681 const unsigned char* symbols
,
5684 unsigned int reloc_shndx
,
5685 unsigned int reloc_type
);
5688 #ifdef HAVE_TARGET_32_BIG
5691 Layout::add_to_gdb_index(bool is_type_unit
,
5692 Sized_relobj
<32, true>* object
,
5693 const unsigned char* symbols
,
5696 unsigned int reloc_shndx
,
5697 unsigned int reloc_type
);
5700 #ifdef HAVE_TARGET_64_LITTLE
5703 Layout::add_to_gdb_index(bool is_type_unit
,
5704 Sized_relobj
<64, false>* object
,
5705 const unsigned char* symbols
,
5708 unsigned int reloc_shndx
,
5709 unsigned int reloc_type
);
5712 #ifdef HAVE_TARGET_64_BIG
5715 Layout::add_to_gdb_index(bool is_type_unit
,
5716 Sized_relobj
<64, true>* object
,
5717 const unsigned char* symbols
,
5720 unsigned int reloc_shndx
,
5721 unsigned int reloc_type
);
5724 } // End namespace gold.