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 (parameters
->options().text_reorder()
1153 && !this->script_options_
->saw_sections_clause()
1154 && !this->is_section_ordering_specified()
1155 && !parameters
->options().relocatable()
1156 && Layout::special_ordering_of_input_section(name
) >= 0)
1157 os
->set_must_sort_attached_input_sections();
1159 // If this is a .ctors or .ctors.* section being mapped to a
1160 // .init_array section, or a .dtors or .dtors.* section being mapped
1161 // to a .fini_array section, we will need to reverse the words if
1162 // there is more than one. Record this section for later. See
1163 // ctors_sections_in_init_array above.
1164 if (!this->script_options_
->saw_sections_clause()
1165 && !parameters
->options().relocatable()
1166 && shdr
.get_sh_size() > size
/ 8
1167 && (((strcmp(name
, ".ctors") == 0
1168 || is_prefix_of(".ctors.", name
))
1169 && strcmp(os
->name(), ".init_array") == 0)
1170 || ((strcmp(name
, ".dtors") == 0
1171 || is_prefix_of(".dtors.", name
))
1172 && strcmp(os
->name(), ".fini_array") == 0)))
1173 ctors_sections_in_init_array
.insert(Section_id(object
, shndx
));
1175 // FIXME: Handle SHF_LINK_ORDER somewhere.
1177 elfcpp::Elf_Xword orig_flags
= os
->flags();
1179 *off
= os
->add_input_section(this, object
, shndx
, name
, shdr
, reloc_shndx
,
1180 this->script_options_
->saw_sections_clause());
1182 // If the flags changed, we may have to change the order.
1183 if ((orig_flags
& elfcpp::SHF_ALLOC
) != 0)
1185 orig_flags
&= (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
1186 elfcpp::Elf_Xword new_flags
=
1187 os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
);
1188 if (orig_flags
!= new_flags
)
1189 os
->set_order(this->default_section_order(os
, false));
1192 this->have_added_input_section_
= true;
1197 // Maps section SECN to SEGMENT s.
1199 Layout::insert_section_segment_map(Const_section_id secn
,
1200 Unique_segment_info
*s
)
1202 gold_assert(this->unique_segment_for_sections_specified_
);
1203 this->section_segment_map_
[secn
] = s
;
1206 // Handle a relocation section when doing a relocatable link.
1208 template<int size
, bool big_endian
>
1210 Layout::layout_reloc(Sized_relobj_file
<size
, big_endian
>* object
,
1212 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1213 Output_section
* data_section
,
1214 Relocatable_relocs
* rr
)
1216 gold_assert(parameters
->options().relocatable()
1217 || parameters
->options().emit_relocs());
1219 int sh_type
= shdr
.get_sh_type();
1222 if (sh_type
== elfcpp::SHT_REL
)
1224 else if (sh_type
== elfcpp::SHT_RELA
)
1228 name
+= data_section
->name();
1230 // In a relocatable link relocs for a grouped section must not be
1231 // combined with other reloc sections.
1233 if (!parameters
->options().relocatable()
1234 || (data_section
->flags() & elfcpp::SHF_GROUP
) == 0)
1235 os
= this->choose_output_section(object
, name
.c_str(), sh_type
,
1236 shdr
.get_sh_flags(), false,
1237 ORDER_INVALID
, false);
1240 const char* n
= this->namepool_
.add(name
.c_str(), true, NULL
);
1241 os
= this->make_output_section(n
, sh_type
, shdr
.get_sh_flags(),
1242 ORDER_INVALID
, false);
1245 os
->set_should_link_to_symtab();
1246 os
->set_info_section(data_section
);
1248 Output_section_data
* posd
;
1249 if (sh_type
== elfcpp::SHT_REL
)
1251 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rel_size
);
1252 posd
= new Output_relocatable_relocs
<elfcpp::SHT_REL
,
1256 else if (sh_type
== elfcpp::SHT_RELA
)
1258 os
->set_entsize(elfcpp::Elf_sizes
<size
>::rela_size
);
1259 posd
= new Output_relocatable_relocs
<elfcpp::SHT_RELA
,
1266 os
->add_output_section_data(posd
);
1267 rr
->set_output_data(posd
);
1272 // Handle a group section when doing a relocatable link.
1274 template<int size
, bool big_endian
>
1276 Layout::layout_group(Symbol_table
* symtab
,
1277 Sized_relobj_file
<size
, big_endian
>* object
,
1279 const char* group_section_name
,
1280 const char* signature
,
1281 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1282 elfcpp::Elf_Word flags
,
1283 std::vector
<unsigned int>* shndxes
)
1285 gold_assert(parameters
->options().relocatable());
1286 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_GROUP
);
1287 group_section_name
= this->namepool_
.add(group_section_name
, true, NULL
);
1288 Output_section
* os
= this->make_output_section(group_section_name
,
1290 shdr
.get_sh_flags(),
1291 ORDER_INVALID
, false);
1293 // We need to find a symbol with the signature in the symbol table.
1294 // If we don't find one now, we need to look again later.
1295 Symbol
* sym
= symtab
->lookup(signature
, NULL
);
1297 os
->set_info_symndx(sym
);
1300 // Reserve some space to minimize reallocations.
1301 if (this->group_signatures_
.empty())
1302 this->group_signatures_
.reserve(this->number_of_input_files_
* 16);
1304 // We will wind up using a symbol whose name is the signature.
1305 // So just put the signature in the symbol name pool to save it.
1306 signature
= symtab
->canonicalize_name(signature
);
1307 this->group_signatures_
.push_back(Group_signature(os
, signature
));
1310 os
->set_should_link_to_symtab();
1313 section_size_type entry_count
=
1314 convert_to_section_size_type(shdr
.get_sh_size() / 4);
1315 Output_section_data
* posd
=
1316 new Output_data_group
<size
, big_endian
>(object
, entry_count
, flags
,
1318 os
->add_output_section_data(posd
);
1321 // Special GNU handling of sections name .eh_frame. They will
1322 // normally hold exception frame data as defined by the C++ ABI
1323 // (http://codesourcery.com/cxx-abi/).
1325 template<int size
, bool big_endian
>
1327 Layout::layout_eh_frame(Sized_relobj_file
<size
, big_endian
>* object
,
1328 const unsigned char* symbols
,
1330 const unsigned char* symbol_names
,
1331 off_t symbol_names_size
,
1333 const elfcpp::Shdr
<size
, big_endian
>& shdr
,
1334 unsigned int reloc_shndx
, unsigned int reloc_type
,
1337 gold_assert(shdr
.get_sh_type() == elfcpp::SHT_PROGBITS
1338 || shdr
.get_sh_type() == elfcpp::SHT_X86_64_UNWIND
);
1339 gold_assert((shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) != 0);
1341 Output_section
* os
= this->make_eh_frame_section(object
);
1345 gold_assert(this->eh_frame_section_
== os
);
1347 elfcpp::Elf_Xword orig_flags
= os
->flags();
1349 if (!parameters
->incremental()
1350 && this->eh_frame_data_
->add_ehframe_input_section(object
,
1359 os
->update_flags_for_input_section(shdr
.get_sh_flags());
1361 // A writable .eh_frame section is a RELRO section.
1362 if ((orig_flags
& (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
))
1363 != (os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
)))
1366 os
->set_order(ORDER_RELRO
);
1369 // We found a .eh_frame section we are going to optimize, so now
1370 // we can add the set of optimized sections to the output
1371 // section. We need to postpone adding this until we've found a
1372 // section we can optimize so that the .eh_frame section in
1373 // crtbegin.o winds up at the start of the output section.
1374 if (!this->added_eh_frame_data_
)
1376 os
->add_output_section_data(this->eh_frame_data_
);
1377 this->added_eh_frame_data_
= true;
1383 // We couldn't handle this .eh_frame section for some reason.
1384 // Add it as a normal section.
1385 bool saw_sections_clause
= this->script_options_
->saw_sections_clause();
1386 *off
= os
->add_input_section(this, object
, shndx
, ".eh_frame", shdr
,
1387 reloc_shndx
, saw_sections_clause
);
1388 this->have_added_input_section_
= true;
1390 if ((orig_flags
& (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
))
1391 != (os
->flags() & (elfcpp::SHF_WRITE
| elfcpp::SHF_EXECINSTR
)))
1392 os
->set_order(this->default_section_order(os
, false));
1398 // Create and return the magic .eh_frame section. Create
1399 // .eh_frame_hdr also if appropriate. OBJECT is the object with the
1400 // input .eh_frame section; it may be NULL.
1403 Layout::make_eh_frame_section(const Relobj
* object
)
1405 // FIXME: On x86_64, this could use SHT_X86_64_UNWIND rather than
1407 Output_section
* os
= this->choose_output_section(object
, ".eh_frame",
1408 elfcpp::SHT_PROGBITS
,
1409 elfcpp::SHF_ALLOC
, false,
1410 ORDER_EHFRAME
, false);
1414 if (this->eh_frame_section_
== NULL
)
1416 this->eh_frame_section_
= os
;
1417 this->eh_frame_data_
= new Eh_frame();
1419 // For incremental linking, we do not optimize .eh_frame sections
1420 // or create a .eh_frame_hdr section.
1421 if (parameters
->options().eh_frame_hdr() && !parameters
->incremental())
1423 Output_section
* hdr_os
=
1424 this->choose_output_section(NULL
, ".eh_frame_hdr",
1425 elfcpp::SHT_PROGBITS
,
1426 elfcpp::SHF_ALLOC
, false,
1427 ORDER_EHFRAME
, false);
1431 Eh_frame_hdr
* hdr_posd
= new Eh_frame_hdr(os
,
1432 this->eh_frame_data_
);
1433 hdr_os
->add_output_section_data(hdr_posd
);
1435 hdr_os
->set_after_input_sections();
1437 if (!this->script_options_
->saw_phdrs_clause())
1439 Output_segment
* hdr_oseg
;
1440 hdr_oseg
= this->make_output_segment(elfcpp::PT_GNU_EH_FRAME
,
1442 hdr_oseg
->add_output_section_to_nonload(hdr_os
,
1446 this->eh_frame_data_
->set_eh_frame_hdr(hdr_posd
);
1454 // Add an exception frame for a PLT. This is called from target code.
1457 Layout::add_eh_frame_for_plt(Output_data
* plt
, const unsigned char* cie_data
,
1458 size_t cie_length
, const unsigned char* fde_data
,
1461 if (parameters
->incremental())
1463 // FIXME: Maybe this could work some day....
1466 Output_section
* os
= this->make_eh_frame_section(NULL
);
1469 this->eh_frame_data_
->add_ehframe_for_plt(plt
, cie_data
, cie_length
,
1470 fde_data
, fde_length
);
1471 if (!this->added_eh_frame_data_
)
1473 os
->add_output_section_data(this->eh_frame_data_
);
1474 this->added_eh_frame_data_
= true;
1478 // Scan a .debug_info or .debug_types section, and add summary
1479 // information to the .gdb_index section.
1481 template<int size
, bool big_endian
>
1483 Layout::add_to_gdb_index(bool is_type_unit
,
1484 Sized_relobj
<size
, big_endian
>* object
,
1485 const unsigned char* symbols
,
1488 unsigned int reloc_shndx
,
1489 unsigned int reloc_type
)
1491 if (this->gdb_index_data_
== NULL
)
1493 Output_section
* os
= this->choose_output_section(NULL
, ".gdb_index",
1494 elfcpp::SHT_PROGBITS
, 0,
1495 false, ORDER_INVALID
,
1500 this->gdb_index_data_
= new Gdb_index(os
);
1501 os
->add_output_section_data(this->gdb_index_data_
);
1502 os
->set_after_input_sections();
1505 this->gdb_index_data_
->scan_debug_info(is_type_unit
, object
, symbols
,
1506 symbols_size
, shndx
, reloc_shndx
,
1510 // Add POSD to an output section using NAME, TYPE, and FLAGS. Return
1511 // the output section.
1514 Layout::add_output_section_data(const char* name
, elfcpp::Elf_Word type
,
1515 elfcpp::Elf_Xword flags
,
1516 Output_section_data
* posd
,
1517 Output_section_order order
, bool is_relro
)
1519 Output_section
* os
= this->choose_output_section(NULL
, name
, type
, flags
,
1520 false, order
, is_relro
);
1522 os
->add_output_section_data(posd
);
1526 // Map section flags to segment flags.
1529 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags
)
1531 elfcpp::Elf_Word ret
= elfcpp::PF_R
;
1532 if ((flags
& elfcpp::SHF_WRITE
) != 0)
1533 ret
|= elfcpp::PF_W
;
1534 if ((flags
& elfcpp::SHF_EXECINSTR
) != 0)
1535 ret
|= elfcpp::PF_X
;
1539 // Make a new Output_section, and attach it to segments as
1540 // appropriate. ORDER is the order in which this section should
1541 // appear in the output segment. IS_RELRO is true if this is a relro
1542 // (read-only after relocations) section.
1545 Layout::make_output_section(const char* name
, elfcpp::Elf_Word type
,
1546 elfcpp::Elf_Xword flags
,
1547 Output_section_order order
, bool is_relro
)
1550 if ((flags
& elfcpp::SHF_ALLOC
) == 0
1551 && strcmp(parameters
->options().compress_debug_sections(), "none") != 0
1552 && is_compressible_debug_section(name
))
1553 os
= new Output_compressed_section(¶meters
->options(), name
, type
,
1555 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1556 && parameters
->options().strip_debug_non_line()
1557 && strcmp(".debug_abbrev", name
) == 0)
1559 os
= this->debug_abbrev_
= new Output_reduced_debug_abbrev_section(
1561 if (this->debug_info_
)
1562 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1564 else if ((flags
& elfcpp::SHF_ALLOC
) == 0
1565 && parameters
->options().strip_debug_non_line()
1566 && strcmp(".debug_info", name
) == 0)
1568 os
= this->debug_info_
= new Output_reduced_debug_info_section(
1570 if (this->debug_abbrev_
)
1571 this->debug_info_
->set_abbreviations(this->debug_abbrev_
);
1575 // Sometimes .init_array*, .preinit_array* and .fini_array* do
1576 // not have correct section types. Force them here.
1577 if (type
== elfcpp::SHT_PROGBITS
)
1579 if (is_prefix_of(".init_array", name
))
1580 type
= elfcpp::SHT_INIT_ARRAY
;
1581 else if (is_prefix_of(".preinit_array", name
))
1582 type
= elfcpp::SHT_PREINIT_ARRAY
;
1583 else if (is_prefix_of(".fini_array", name
))
1584 type
= elfcpp::SHT_FINI_ARRAY
;
1587 // FIXME: const_cast is ugly.
1588 Target
* target
= const_cast<Target
*>(¶meters
->target());
1589 os
= target
->make_output_section(name
, type
, flags
);
1592 // With -z relro, we have to recognize the special sections by name.
1593 // There is no other way.
1594 bool is_relro_local
= false;
1595 if (!this->script_options_
->saw_sections_clause()
1596 && parameters
->options().relro()
1597 && (flags
& elfcpp::SHF_ALLOC
) != 0
1598 && (flags
& elfcpp::SHF_WRITE
) != 0)
1600 if (type
== elfcpp::SHT_PROGBITS
)
1602 if ((flags
& elfcpp::SHF_TLS
) != 0)
1604 else if (strcmp(name
, ".data.rel.ro") == 0)
1606 else if (strcmp(name
, ".data.rel.ro.local") == 0)
1609 is_relro_local
= true;
1611 else if (strcmp(name
, ".ctors") == 0
1612 || strcmp(name
, ".dtors") == 0
1613 || strcmp(name
, ".jcr") == 0)
1616 else if (type
== elfcpp::SHT_INIT_ARRAY
1617 || type
== elfcpp::SHT_FINI_ARRAY
1618 || type
== elfcpp::SHT_PREINIT_ARRAY
)
1625 if (order
== ORDER_INVALID
&& (flags
& elfcpp::SHF_ALLOC
) != 0)
1626 order
= this->default_section_order(os
, is_relro_local
);
1628 os
->set_order(order
);
1630 parameters
->target().new_output_section(os
);
1632 this->section_list_
.push_back(os
);
1634 // The GNU linker by default sorts some sections by priority, so we
1635 // do the same. We need to know that this might happen before we
1636 // attach any input sections.
1637 if (!this->script_options_
->saw_sections_clause()
1638 && !parameters
->options().relocatable()
1639 && (strcmp(name
, ".init_array") == 0
1640 || strcmp(name
, ".fini_array") == 0
1641 || (!parameters
->options().ctors_in_init_array()
1642 && (strcmp(name
, ".ctors") == 0
1643 || strcmp(name
, ".dtors") == 0))))
1644 os
->set_may_sort_attached_input_sections();
1646 // The GNU linker by default sorts .text.{unlikely,exit,startup,hot}
1647 // sections before other .text sections. We are compatible. We
1648 // need to know that this might happen before we attach any input
1650 if (parameters
->options().text_reorder()
1651 && !this->script_options_
->saw_sections_clause()
1652 && !this->is_section_ordering_specified()
1653 && !parameters
->options().relocatable()
1654 && strcmp(name
, ".text") == 0)
1655 os
->set_may_sort_attached_input_sections();
1657 // Check for .stab*str sections, as .stab* sections need to link to
1659 if (type
== elfcpp::SHT_STRTAB
1660 && !this->have_stabstr_section_
1661 && strncmp(name
, ".stab", 5) == 0
1662 && strcmp(name
+ strlen(name
) - 3, "str") == 0)
1663 this->have_stabstr_section_
= true;
1665 // During a full incremental link, we add patch space to most
1666 // PROGBITS and NOBITS sections. Flag those that may be
1667 // arbitrarily padded.
1668 if ((type
== elfcpp::SHT_PROGBITS
|| type
== elfcpp::SHT_NOBITS
)
1669 && order
!= ORDER_INTERP
1670 && order
!= ORDER_INIT
1671 && order
!= ORDER_PLT
1672 && order
!= ORDER_FINI
1673 && order
!= ORDER_RELRO_LAST
1674 && order
!= ORDER_NON_RELRO_FIRST
1675 && strcmp(name
, ".eh_frame") != 0
1676 && strcmp(name
, ".ctors") != 0
1677 && strcmp(name
, ".dtors") != 0
1678 && strcmp(name
, ".jcr") != 0)
1680 os
->set_is_patch_space_allowed();
1682 // Certain sections require "holes" to be filled with
1683 // specific fill patterns. These fill patterns may have
1684 // a minimum size, so we must prevent allocations from the
1685 // free list that leave a hole smaller than the minimum.
1686 if (strcmp(name
, ".debug_info") == 0)
1687 os
->set_free_space_fill(new Output_fill_debug_info(false));
1688 else if (strcmp(name
, ".debug_types") == 0)
1689 os
->set_free_space_fill(new Output_fill_debug_info(true));
1690 else if (strcmp(name
, ".debug_line") == 0)
1691 os
->set_free_space_fill(new Output_fill_debug_line());
1694 // If we have already attached the sections to segments, then we
1695 // need to attach this one now. This happens for sections created
1696 // directly by the linker.
1697 if (this->sections_are_attached_
)
1698 this->attach_section_to_segment(¶meters
->target(), os
);
1703 // Return the default order in which a section should be placed in an
1704 // output segment. This function captures a lot of the ideas in
1705 // ld/scripttempl/elf.sc in the GNU linker. Note that the order of a
1706 // linker created section is normally set when the section is created;
1707 // this function is used for input sections.
1709 Output_section_order
1710 Layout::default_section_order(Output_section
* os
, bool is_relro_local
)
1712 gold_assert((os
->flags() & elfcpp::SHF_ALLOC
) != 0);
1713 bool is_write
= (os
->flags() & elfcpp::SHF_WRITE
) != 0;
1714 bool is_execinstr
= (os
->flags() & elfcpp::SHF_EXECINSTR
) != 0;
1715 bool is_bss
= false;
1720 case elfcpp::SHT_PROGBITS
:
1722 case elfcpp::SHT_NOBITS
:
1725 case elfcpp::SHT_RELA
:
1726 case elfcpp::SHT_REL
:
1728 return ORDER_DYNAMIC_RELOCS
;
1730 case elfcpp::SHT_HASH
:
1731 case elfcpp::SHT_DYNAMIC
:
1732 case elfcpp::SHT_SHLIB
:
1733 case elfcpp::SHT_DYNSYM
:
1734 case elfcpp::SHT_GNU_HASH
:
1735 case elfcpp::SHT_GNU_verdef
:
1736 case elfcpp::SHT_GNU_verneed
:
1737 case elfcpp::SHT_GNU_versym
:
1739 return ORDER_DYNAMIC_LINKER
;
1741 case elfcpp::SHT_NOTE
:
1742 return is_write
? ORDER_RW_NOTE
: ORDER_RO_NOTE
;
1745 if ((os
->flags() & elfcpp::SHF_TLS
) != 0)
1746 return is_bss
? ORDER_TLS_BSS
: ORDER_TLS_DATA
;
1748 if (!is_bss
&& !is_write
)
1752 if (strcmp(os
->name(), ".init") == 0)
1754 else if (strcmp(os
->name(), ".fini") == 0)
1757 return is_execinstr
? ORDER_TEXT
: ORDER_READONLY
;
1761 return is_relro_local
? ORDER_RELRO_LOCAL
: ORDER_RELRO
;
1763 if (os
->is_small_section())
1764 return is_bss
? ORDER_SMALL_BSS
: ORDER_SMALL_DATA
;
1765 if (os
->is_large_section())
1766 return is_bss
? ORDER_LARGE_BSS
: ORDER_LARGE_DATA
;
1768 return is_bss
? ORDER_BSS
: ORDER_DATA
;
1771 // Attach output sections to segments. This is called after we have
1772 // seen all the input sections.
1775 Layout::attach_sections_to_segments(const Target
* target
)
1777 for (Section_list::iterator p
= this->section_list_
.begin();
1778 p
!= this->section_list_
.end();
1780 this->attach_section_to_segment(target
, *p
);
1782 this->sections_are_attached_
= true;
1785 // Attach an output section to a segment.
1788 Layout::attach_section_to_segment(const Target
* target
, Output_section
* os
)
1790 if ((os
->flags() & elfcpp::SHF_ALLOC
) == 0)
1791 this->unattached_section_list_
.push_back(os
);
1793 this->attach_allocated_section_to_segment(target
, os
);
1796 // Attach an allocated output section to a segment.
1799 Layout::attach_allocated_section_to_segment(const Target
* target
,
1802 elfcpp::Elf_Xword flags
= os
->flags();
1803 gold_assert((flags
& elfcpp::SHF_ALLOC
) != 0);
1805 if (parameters
->options().relocatable())
1808 // If we have a SECTIONS clause, we can't handle the attachment to
1809 // segments until after we've seen all the sections.
1810 if (this->script_options_
->saw_sections_clause())
1813 gold_assert(!this->script_options_
->saw_phdrs_clause());
1815 // This output section goes into a PT_LOAD segment.
1817 elfcpp::Elf_Word seg_flags
= Layout::section_flags_to_segment(flags
);
1819 // If this output section's segment has extra flags that need to be set,
1820 // coming from a linker plugin, do that.
1821 seg_flags
|= os
->extra_segment_flags();
1823 // Check for --section-start.
1825 bool is_address_set
= parameters
->options().section_start(os
->name(), &addr
);
1827 // In general the only thing we really care about for PT_LOAD
1828 // segments is whether or not they are writable or executable,
1829 // so that is how we search for them.
1830 // Large data sections also go into their own PT_LOAD segment.
1831 // People who need segments sorted on some other basis will
1832 // have to use a linker script.
1834 Segment_list::const_iterator p
;
1835 if (!os
->is_unique_segment())
1837 for (p
= this->segment_list_
.begin();
1838 p
!= this->segment_list_
.end();
1841 if ((*p
)->type() != elfcpp::PT_LOAD
)
1843 if ((*p
)->is_unique_segment())
1845 if (!parameters
->options().omagic()
1846 && ((*p
)->flags() & elfcpp::PF_W
) != (seg_flags
& elfcpp::PF_W
))
1848 if ((target
->isolate_execinstr() || parameters
->options().rosegment())
1849 && ((*p
)->flags() & elfcpp::PF_X
) != (seg_flags
& elfcpp::PF_X
))
1851 // If -Tbss was specified, we need to separate the data and BSS
1853 if (parameters
->options().user_set_Tbss())
1855 if ((os
->type() == elfcpp::SHT_NOBITS
)
1856 == (*p
)->has_any_data_sections())
1859 if (os
->is_large_data_section() && !(*p
)->is_large_data_segment())
1864 if ((*p
)->are_addresses_set())
1867 (*p
)->add_initial_output_data(os
);
1868 (*p
)->update_flags_for_output_section(seg_flags
);
1869 (*p
)->set_addresses(addr
, addr
);
1873 (*p
)->add_output_section_to_load(this, os
, seg_flags
);
1878 if (p
== this->segment_list_
.end()
1879 || os
->is_unique_segment())
1881 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_LOAD
,
1883 if (os
->is_large_data_section())
1884 oseg
->set_is_large_data_segment();
1885 oseg
->add_output_section_to_load(this, os
, seg_flags
);
1887 oseg
->set_addresses(addr
, addr
);
1888 // Check if segment should be marked unique. For segments marked
1889 // unique by linker plugins, set the new alignment if specified.
1890 if (os
->is_unique_segment())
1892 oseg
->set_is_unique_segment();
1893 if (os
->segment_alignment() != 0)
1894 oseg
->set_minimum_p_align(os
->segment_alignment());
1898 // If we see a loadable SHT_NOTE section, we create a PT_NOTE
1900 if (os
->type() == elfcpp::SHT_NOTE
)
1902 // See if we already have an equivalent PT_NOTE segment.
1903 for (p
= this->segment_list_
.begin();
1904 p
!= segment_list_
.end();
1907 if ((*p
)->type() == elfcpp::PT_NOTE
1908 && (((*p
)->flags() & elfcpp::PF_W
)
1909 == (seg_flags
& elfcpp::PF_W
)))
1911 (*p
)->add_output_section_to_nonload(os
, seg_flags
);
1916 if (p
== this->segment_list_
.end())
1918 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_NOTE
,
1920 oseg
->add_output_section_to_nonload(os
, seg_flags
);
1924 // If we see a loadable SHF_TLS section, we create a PT_TLS
1925 // segment. There can only be one such segment.
1926 if ((flags
& elfcpp::SHF_TLS
) != 0)
1928 if (this->tls_segment_
== NULL
)
1929 this->make_output_segment(elfcpp::PT_TLS
, seg_flags
);
1930 this->tls_segment_
->add_output_section_to_nonload(os
, seg_flags
);
1933 // If -z relro is in effect, and we see a relro section, we create a
1934 // PT_GNU_RELRO segment. There can only be one such segment.
1935 if (os
->is_relro() && parameters
->options().relro())
1937 gold_assert(seg_flags
== (elfcpp::PF_R
| elfcpp::PF_W
));
1938 if (this->relro_segment_
== NULL
)
1939 this->make_output_segment(elfcpp::PT_GNU_RELRO
, seg_flags
);
1940 this->relro_segment_
->add_output_section_to_nonload(os
, seg_flags
);
1943 // If we see a section named .interp, put it into a PT_INTERP
1944 // segment. This seems broken to me, but this is what GNU ld does,
1945 // and glibc expects it.
1946 if (strcmp(os
->name(), ".interp") == 0
1947 && !this->script_options_
->saw_phdrs_clause())
1949 if (this->interp_segment_
== NULL
)
1950 this->make_output_segment(elfcpp::PT_INTERP
, seg_flags
);
1952 gold_warning(_("multiple '.interp' sections in input files "
1953 "may cause confusing PT_INTERP segment"));
1954 this->interp_segment_
->add_output_section_to_nonload(os
, seg_flags
);
1958 // Make an output section for a script.
1961 Layout::make_output_section_for_script(
1963 Script_sections::Section_type section_type
)
1965 name
= this->namepool_
.add(name
, false, NULL
);
1966 elfcpp::Elf_Xword sh_flags
= elfcpp::SHF_ALLOC
;
1967 if (section_type
== Script_sections::ST_NOLOAD
)
1969 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_PROGBITS
,
1970 sh_flags
, ORDER_INVALID
,
1972 os
->set_found_in_sections_clause();
1973 if (section_type
== Script_sections::ST_NOLOAD
)
1974 os
->set_is_noload();
1978 // Return the number of segments we expect to see.
1981 Layout::expected_segment_count() const
1983 size_t ret
= this->segment_list_
.size();
1985 // If we didn't see a SECTIONS clause in a linker script, we should
1986 // already have the complete list of segments. Otherwise we ask the
1987 // SECTIONS clause how many segments it expects, and add in the ones
1988 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
1990 if (!this->script_options_
->saw_sections_clause())
1994 const Script_sections
* ss
= this->script_options_
->script_sections();
1995 return ret
+ ss
->expected_segment_count(this);
1999 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
2000 // is whether we saw a .note.GNU-stack section in the object file.
2001 // GNU_STACK_FLAGS is the section flags. The flags give the
2002 // protection required for stack memory. We record this in an
2003 // executable as a PT_GNU_STACK segment. If an object file does not
2004 // have a .note.GNU-stack segment, we must assume that it is an old
2005 // object. On some targets that will force an executable stack.
2008 Layout::layout_gnu_stack(bool seen_gnu_stack
, uint64_t gnu_stack_flags
,
2011 if (!seen_gnu_stack
)
2013 this->input_without_gnu_stack_note_
= true;
2014 if (parameters
->options().warn_execstack()
2015 && parameters
->target().is_default_stack_executable())
2016 gold_warning(_("%s: missing .note.GNU-stack section"
2017 " implies executable stack"),
2018 obj
->name().c_str());
2022 this->input_with_gnu_stack_note_
= true;
2023 if ((gnu_stack_flags
& elfcpp::SHF_EXECINSTR
) != 0)
2025 this->input_requires_executable_stack_
= true;
2026 if (parameters
->options().warn_execstack()
2027 || parameters
->options().is_stack_executable())
2028 gold_warning(_("%s: requires executable stack"),
2029 obj
->name().c_str());
2034 // Create automatic note sections.
2037 Layout::create_notes()
2039 this->create_gold_note();
2040 this->create_executable_stack_info();
2041 this->create_build_id();
2044 // Create the dynamic sections which are needed before we read the
2048 Layout::create_initial_dynamic_sections(Symbol_table
* symtab
)
2050 if (parameters
->doing_static_link())
2053 this->dynamic_section_
= this->choose_output_section(NULL
, ".dynamic",
2054 elfcpp::SHT_DYNAMIC
,
2056 | elfcpp::SHF_WRITE
),
2060 // A linker script may discard .dynamic, so check for NULL.
2061 if (this->dynamic_section_
!= NULL
)
2063 this->dynamic_symbol_
=
2064 symtab
->define_in_output_data("_DYNAMIC", NULL
,
2065 Symbol_table::PREDEFINED
,
2066 this->dynamic_section_
, 0, 0,
2067 elfcpp::STT_OBJECT
, elfcpp::STB_LOCAL
,
2068 elfcpp::STV_HIDDEN
, 0, false, false);
2070 this->dynamic_data_
= new Output_data_dynamic(&this->dynpool_
);
2072 this->dynamic_section_
->add_output_section_data(this->dynamic_data_
);
2076 // For each output section whose name can be represented as C symbol,
2077 // define __start and __stop symbols for the section. This is a GNU
2081 Layout::define_section_symbols(Symbol_table
* symtab
)
2083 for (Section_list::const_iterator p
= this->section_list_
.begin();
2084 p
!= this->section_list_
.end();
2087 const char* const name
= (*p
)->name();
2088 if (is_cident(name
))
2090 const std::string
name_string(name
);
2091 const std::string
start_name(cident_section_start_prefix
2093 const std::string
stop_name(cident_section_stop_prefix
2096 symtab
->define_in_output_data(start_name
.c_str(),
2098 Symbol_table::PREDEFINED
,
2104 elfcpp::STV_DEFAULT
,
2106 false, // offset_is_from_end
2107 true); // only_if_ref
2109 symtab
->define_in_output_data(stop_name
.c_str(),
2111 Symbol_table::PREDEFINED
,
2117 elfcpp::STV_DEFAULT
,
2119 true, // offset_is_from_end
2120 true); // only_if_ref
2125 // Define symbols for group signatures.
2128 Layout::define_group_signatures(Symbol_table
* symtab
)
2130 for (Group_signatures::iterator p
= this->group_signatures_
.begin();
2131 p
!= this->group_signatures_
.end();
2134 Symbol
* sym
= symtab
->lookup(p
->signature
, NULL
);
2136 p
->section
->set_info_symndx(sym
);
2139 // Force the name of the group section to the group
2140 // signature, and use the group's section symbol as the
2141 // signature symbol.
2142 if (strcmp(p
->section
->name(), p
->signature
) != 0)
2144 const char* name
= this->namepool_
.add(p
->signature
,
2146 p
->section
->set_name(name
);
2148 p
->section
->set_needs_symtab_index();
2149 p
->section
->set_info_section_symndx(p
->section
);
2153 this->group_signatures_
.clear();
2156 // Find the first read-only PT_LOAD segment, creating one if
2160 Layout::find_first_load_seg(const Target
* target
)
2162 Output_segment
* best
= NULL
;
2163 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
2164 p
!= this->segment_list_
.end();
2167 if ((*p
)->type() == elfcpp::PT_LOAD
2168 && ((*p
)->flags() & elfcpp::PF_R
) != 0
2169 && (parameters
->options().omagic()
2170 || ((*p
)->flags() & elfcpp::PF_W
) == 0)
2171 && (!target
->isolate_execinstr()
2172 || ((*p
)->flags() & elfcpp::PF_X
) == 0))
2174 if (best
== NULL
|| this->segment_precedes(*p
, best
))
2181 gold_assert(!this->script_options_
->saw_phdrs_clause());
2183 Output_segment
* load_seg
= this->make_output_segment(elfcpp::PT_LOAD
,
2188 // Save states of all current output segments. Store saved states
2189 // in SEGMENT_STATES.
2192 Layout::save_segments(Segment_states
* segment_states
)
2194 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
2195 p
!= this->segment_list_
.end();
2198 Output_segment
* segment
= *p
;
2200 Output_segment
* copy
= new Output_segment(*segment
);
2201 (*segment_states
)[segment
] = copy
;
2205 // Restore states of output segments and delete any segment not found in
2209 Layout::restore_segments(const Segment_states
* segment_states
)
2211 // Go through the segment list and remove any segment added in the
2213 this->tls_segment_
= NULL
;
2214 this->relro_segment_
= NULL
;
2215 Segment_list::iterator list_iter
= this->segment_list_
.begin();
2216 while (list_iter
!= this->segment_list_
.end())
2218 Output_segment
* segment
= *list_iter
;
2219 Segment_states::const_iterator states_iter
=
2220 segment_states
->find(segment
);
2221 if (states_iter
!= segment_states
->end())
2223 const Output_segment
* copy
= states_iter
->second
;
2224 // Shallow copy to restore states.
2227 // Also fix up TLS and RELRO segment pointers as appropriate.
2228 if (segment
->type() == elfcpp::PT_TLS
)
2229 this->tls_segment_
= segment
;
2230 else if (segment
->type() == elfcpp::PT_GNU_RELRO
)
2231 this->relro_segment_
= segment
;
2237 list_iter
= this->segment_list_
.erase(list_iter
);
2238 // This is a segment created during section layout. It should be
2239 // safe to remove it since we should have removed all pointers to it.
2245 // Clean up after relaxation so that sections can be laid out again.
2248 Layout::clean_up_after_relaxation()
2250 // Restore the segments to point state just prior to the relaxation loop.
2251 Script_sections
* script_section
= this->script_options_
->script_sections();
2252 script_section
->release_segments();
2253 this->restore_segments(this->segment_states_
);
2255 // Reset section addresses and file offsets
2256 for (Section_list::iterator p
= this->section_list_
.begin();
2257 p
!= this->section_list_
.end();
2260 (*p
)->restore_states();
2262 // If an input section changes size because of relaxation,
2263 // we need to adjust the section offsets of all input sections.
2264 // after such a section.
2265 if ((*p
)->section_offsets_need_adjustment())
2266 (*p
)->adjust_section_offsets();
2268 (*p
)->reset_address_and_file_offset();
2271 // Reset special output object address and file offsets.
2272 for (Data_list::iterator p
= this->special_output_list_
.begin();
2273 p
!= this->special_output_list_
.end();
2275 (*p
)->reset_address_and_file_offset();
2277 // A linker script may have created some output section data objects.
2278 // They are useless now.
2279 for (Output_section_data_list::const_iterator p
=
2280 this->script_output_section_data_list_
.begin();
2281 p
!= this->script_output_section_data_list_
.end();
2284 this->script_output_section_data_list_
.clear();
2287 // Prepare for relaxation.
2290 Layout::prepare_for_relaxation()
2292 // Create an relaxation debug check if in debugging mode.
2293 if (is_debugging_enabled(DEBUG_RELAXATION
))
2294 this->relaxation_debug_check_
= new Relaxation_debug_check();
2296 // Save segment states.
2297 this->segment_states_
= new Segment_states();
2298 this->save_segments(this->segment_states_
);
2300 for(Section_list::const_iterator p
= this->section_list_
.begin();
2301 p
!= this->section_list_
.end();
2303 (*p
)->save_states();
2305 if (is_debugging_enabled(DEBUG_RELAXATION
))
2306 this->relaxation_debug_check_
->check_output_data_for_reset_values(
2307 this->section_list_
, this->special_output_list_
);
2309 // Also enable recording of output section data from scripts.
2310 this->record_output_section_data_from_script_
= true;
2313 // Relaxation loop body: If target has no relaxation, this runs only once
2314 // Otherwise, the target relaxation hook is called at the end of
2315 // each iteration. If the hook returns true, it means re-layout of
2316 // section is required.
2318 // The number of segments created by a linking script without a PHDRS
2319 // clause may be affected by section sizes and alignments. There is
2320 // a remote chance that relaxation causes different number of PT_LOAD
2321 // segments are created and sections are attached to different segments.
2322 // Therefore, we always throw away all segments created during section
2323 // layout. In order to be able to restart the section layout, we keep
2324 // a copy of the segment list right before the relaxation loop and use
2325 // that to restore the segments.
2327 // PASS is the current relaxation pass number.
2328 // SYMTAB is a symbol table.
2329 // PLOAD_SEG is the address of a pointer for the load segment.
2330 // PHDR_SEG is a pointer to the PHDR segment.
2331 // SEGMENT_HEADERS points to the output segment header.
2332 // FILE_HEADER points to the output file header.
2333 // PSHNDX is the address to store the output section index.
2336 Layout::relaxation_loop_body(
2339 Symbol_table
* symtab
,
2340 Output_segment
** pload_seg
,
2341 Output_segment
* phdr_seg
,
2342 Output_segment_headers
* segment_headers
,
2343 Output_file_header
* file_header
,
2344 unsigned int* pshndx
)
2346 // If this is not the first iteration, we need to clean up after
2347 // relaxation so that we can lay out the sections again.
2349 this->clean_up_after_relaxation();
2351 // If there is a SECTIONS clause, put all the input sections into
2352 // the required order.
2353 Output_segment
* load_seg
;
2354 if (this->script_options_
->saw_sections_clause())
2355 load_seg
= this->set_section_addresses_from_script(symtab
);
2356 else if (parameters
->options().relocatable())
2359 load_seg
= this->find_first_load_seg(target
);
2361 if (parameters
->options().oformat_enum()
2362 != General_options::OBJECT_FORMAT_ELF
)
2365 // If the user set the address of the text segment, that may not be
2366 // compatible with putting the segment headers and file headers into
2368 if (parameters
->options().user_set_Ttext()
2369 && parameters
->options().Ttext() % target
->abi_pagesize() != 0)
2375 gold_assert(phdr_seg
== NULL
2377 || this->script_options_
->saw_sections_clause());
2379 // If the address of the load segment we found has been set by
2380 // --section-start rather than by a script, then adjust the VMA and
2381 // LMA downward if possible to include the file and section headers.
2382 uint64_t header_gap
= 0;
2383 if (load_seg
!= NULL
2384 && load_seg
->are_addresses_set()
2385 && !this->script_options_
->saw_sections_clause()
2386 && !parameters
->options().relocatable())
2388 file_header
->finalize_data_size();
2389 segment_headers
->finalize_data_size();
2390 size_t sizeof_headers
= (file_header
->data_size()
2391 + segment_headers
->data_size());
2392 const uint64_t abi_pagesize
= target
->abi_pagesize();
2393 uint64_t hdr_paddr
= load_seg
->paddr() - sizeof_headers
;
2394 hdr_paddr
&= ~(abi_pagesize
- 1);
2395 uint64_t subtract
= load_seg
->paddr() - hdr_paddr
;
2396 if (load_seg
->paddr() < subtract
|| load_seg
->vaddr() < subtract
)
2400 load_seg
->set_addresses(load_seg
->vaddr() - subtract
,
2401 load_seg
->paddr() - subtract
);
2402 header_gap
= subtract
- sizeof_headers
;
2406 // Lay out the segment headers.
2407 if (!parameters
->options().relocatable())
2409 gold_assert(segment_headers
!= NULL
);
2410 if (header_gap
!= 0 && load_seg
!= NULL
)
2412 Output_data_zero_fill
* z
= new Output_data_zero_fill(header_gap
, 1);
2413 load_seg
->add_initial_output_data(z
);
2415 if (load_seg
!= NULL
)
2416 load_seg
->add_initial_output_data(segment_headers
);
2417 if (phdr_seg
!= NULL
)
2418 phdr_seg
->add_initial_output_data(segment_headers
);
2421 // Lay out the file header.
2422 if (load_seg
!= NULL
)
2423 load_seg
->add_initial_output_data(file_header
);
2425 if (this->script_options_
->saw_phdrs_clause()
2426 && !parameters
->options().relocatable())
2428 // Support use of FILEHDRS and PHDRS attachments in a PHDRS
2429 // clause in a linker script.
2430 Script_sections
* ss
= this->script_options_
->script_sections();
2431 ss
->put_headers_in_phdrs(file_header
, segment_headers
);
2434 // We set the output section indexes in set_segment_offsets and
2435 // set_section_indexes.
2438 // Set the file offsets of all the segments, and all the sections
2441 if (!parameters
->options().relocatable())
2442 off
= this->set_segment_offsets(target
, load_seg
, pshndx
);
2444 off
= this->set_relocatable_section_offsets(file_header
, pshndx
);
2446 // Verify that the dummy relaxation does not change anything.
2447 if (is_debugging_enabled(DEBUG_RELAXATION
))
2450 this->relaxation_debug_check_
->read_sections(this->section_list_
);
2452 this->relaxation_debug_check_
->verify_sections(this->section_list_
);
2455 *pload_seg
= load_seg
;
2459 // Search the list of patterns and find the postion of the given section
2460 // name in the output section. If the section name matches a glob
2461 // pattern and a non-glob name, then the non-glob position takes
2462 // precedence. Return 0 if no match is found.
2465 Layout::find_section_order_index(const std::string
& section_name
)
2467 Unordered_map
<std::string
, unsigned int>::iterator map_it
;
2468 map_it
= this->input_section_position_
.find(section_name
);
2469 if (map_it
!= this->input_section_position_
.end())
2470 return map_it
->second
;
2472 // Absolute match failed. Linear search the glob patterns.
2473 std::vector
<std::string
>::iterator it
;
2474 for (it
= this->input_section_glob_
.begin();
2475 it
!= this->input_section_glob_
.end();
2478 if (fnmatch((*it
).c_str(), section_name
.c_str(), FNM_NOESCAPE
) == 0)
2480 map_it
= this->input_section_position_
.find(*it
);
2481 gold_assert(map_it
!= this->input_section_position_
.end());
2482 return map_it
->second
;
2488 // Read the sequence of input sections from the file specified with
2489 // option --section-ordering-file.
2492 Layout::read_layout_from_file()
2494 const char* filename
= parameters
->options().section_ordering_file();
2500 gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
2501 filename
, strerror(errno
));
2503 std::getline(in
, line
); // this chops off the trailing \n, if any
2504 unsigned int position
= 1;
2505 this->set_section_ordering_specified();
2509 if (!line
.empty() && line
[line
.length() - 1] == '\r') // Windows
2510 line
.resize(line
.length() - 1);
2511 // Ignore comments, beginning with '#'
2514 std::getline(in
, line
);
2517 this->input_section_position_
[line
] = position
;
2518 // Store all glob patterns in a vector.
2519 if (is_wildcard_string(line
.c_str()))
2520 this->input_section_glob_
.push_back(line
);
2522 std::getline(in
, line
);
2526 // Finalize the layout. When this is called, we have created all the
2527 // output sections and all the output segments which are based on
2528 // input sections. We have several things to do, and we have to do
2529 // them in the right order, so that we get the right results correctly
2532 // 1) Finalize the list of output segments and create the segment
2535 // 2) Finalize the dynamic symbol table and associated sections.
2537 // 3) Determine the final file offset of all the output segments.
2539 // 4) Determine the final file offset of all the SHF_ALLOC output
2542 // 5) Create the symbol table sections and the section name table
2545 // 6) Finalize the symbol table: set symbol values to their final
2546 // value and make a final determination of which symbols are going
2547 // into the output symbol table.
2549 // 7) Create the section table header.
2551 // 8) Determine the final file offset of all the output sections which
2552 // are not SHF_ALLOC, including the section table header.
2554 // 9) Finalize the ELF file header.
2556 // This function returns the size of the output file.
2559 Layout::finalize(const Input_objects
* input_objects
, Symbol_table
* symtab
,
2560 Target
* target
, const Task
* task
)
2562 target
->finalize_sections(this, input_objects
, symtab
);
2564 this->count_local_symbols(task
, input_objects
);
2566 this->link_stabs_sections();
2568 Output_segment
* phdr_seg
= NULL
;
2569 if (!parameters
->options().relocatable() && !parameters
->doing_static_link())
2571 // There was a dynamic object in the link. We need to create
2572 // some information for the dynamic linker.
2574 // Create the PT_PHDR segment which will hold the program
2576 if (!this->script_options_
->saw_phdrs_clause())
2577 phdr_seg
= this->make_output_segment(elfcpp::PT_PHDR
, elfcpp::PF_R
);
2579 // Create the dynamic symbol table, including the hash table.
2580 Output_section
* dynstr
;
2581 std::vector
<Symbol
*> dynamic_symbols
;
2582 unsigned int local_dynamic_count
;
2583 Versions
versions(*this->script_options()->version_script_info(),
2585 this->create_dynamic_symtab(input_objects
, symtab
, &dynstr
,
2586 &local_dynamic_count
, &dynamic_symbols
,
2589 // Create the .interp section to hold the name of the
2590 // interpreter, and put it in a PT_INTERP segment. Don't do it
2591 // if we saw a .interp section in an input file.
2592 if ((!parameters
->options().shared()
2593 || parameters
->options().dynamic_linker() != NULL
)
2594 && this->interp_segment_
== NULL
)
2595 this->create_interp(target
);
2597 // Finish the .dynamic section to hold the dynamic data, and put
2598 // it in a PT_DYNAMIC segment.
2599 this->finish_dynamic_section(input_objects
, symtab
);
2601 // We should have added everything we need to the dynamic string
2603 this->dynpool_
.set_string_offsets();
2605 // Create the version sections. We can't do this until the
2606 // dynamic string table is complete.
2607 this->create_version_sections(&versions
, symtab
, local_dynamic_count
,
2608 dynamic_symbols
, dynstr
);
2610 // Set the size of the _DYNAMIC symbol. We can't do this until
2611 // after we call create_version_sections.
2612 this->set_dynamic_symbol_size(symtab
);
2615 // Create segment headers.
2616 Output_segment_headers
* segment_headers
=
2617 (parameters
->options().relocatable()
2619 : new Output_segment_headers(this->segment_list_
));
2621 // Lay out the file header.
2622 Output_file_header
* file_header
= new Output_file_header(target
, symtab
,
2625 this->special_output_list_
.push_back(file_header
);
2626 if (segment_headers
!= NULL
)
2627 this->special_output_list_
.push_back(segment_headers
);
2629 // Find approriate places for orphan output sections if we are using
2631 if (this->script_options_
->saw_sections_clause())
2632 this->place_orphan_sections_in_script();
2634 Output_segment
* load_seg
;
2639 // Take a snapshot of the section layout as needed.
2640 if (target
->may_relax())
2641 this->prepare_for_relaxation();
2643 // Run the relaxation loop to lay out sections.
2646 off
= this->relaxation_loop_body(pass
, target
, symtab
, &load_seg
,
2647 phdr_seg
, segment_headers
, file_header
,
2651 while (target
->may_relax()
2652 && target
->relax(pass
, input_objects
, symtab
, this, task
));
2654 // If there is a load segment that contains the file and program headers,
2655 // provide a symbol __ehdr_start pointing there.
2656 // A program can use this to examine itself robustly.
2657 if (load_seg
!= NULL
)
2658 symtab
->define_in_output_segment("__ehdr_start", NULL
,
2659 Symbol_table::PREDEFINED
, load_seg
, 0, 0,
2660 elfcpp::STT_NOTYPE
, elfcpp::STB_GLOBAL
,
2661 elfcpp::STV_DEFAULT
, 0,
2662 Symbol::SEGMENT_START
, true);
2664 // Set the file offsets of all the non-data sections we've seen so
2665 // far which don't have to wait for the input sections. We need
2666 // this in order to finalize local symbols in non-allocated
2668 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
2670 // Set the section indexes of all unallocated sections seen so far,
2671 // in case any of them are somehow referenced by a symbol.
2672 shndx
= this->set_section_indexes(shndx
);
2674 // Create the symbol table sections.
2675 this->create_symtab_sections(input_objects
, symtab
, shndx
, &off
);
2676 if (!parameters
->doing_static_link())
2677 this->assign_local_dynsym_offsets(input_objects
);
2679 // Process any symbol assignments from a linker script. This must
2680 // be called after the symbol table has been finalized.
2681 this->script_options_
->finalize_symbols(symtab
, this);
2683 // Create the incremental inputs sections.
2684 if (this->incremental_inputs_
)
2686 this->incremental_inputs_
->finalize();
2687 this->create_incremental_info_sections(symtab
);
2690 // Create the .shstrtab section.
2691 Output_section
* shstrtab_section
= this->create_shstrtab();
2693 // Set the file offsets of the rest of the non-data sections which
2694 // don't have to wait for the input sections.
2695 off
= this->set_section_offsets(off
, BEFORE_INPUT_SECTIONS_PASS
);
2697 // Now that all sections have been created, set the section indexes
2698 // for any sections which haven't been done yet.
2699 shndx
= this->set_section_indexes(shndx
);
2701 // Create the section table header.
2702 this->create_shdrs(shstrtab_section
, &off
);
2704 // If there are no sections which require postprocessing, we can
2705 // handle the section names now, and avoid a resize later.
2706 if (!this->any_postprocessing_sections_
)
2708 off
= this->set_section_offsets(off
,
2709 POSTPROCESSING_SECTIONS_PASS
);
2711 this->set_section_offsets(off
,
2712 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
2715 file_header
->set_section_info(this->section_headers_
, shstrtab_section
);
2717 // Now we know exactly where everything goes in the output file
2718 // (except for non-allocated sections which require postprocessing).
2719 Output_data::layout_complete();
2721 this->output_file_size_
= off
;
2726 // Create a note header following the format defined in the ELF ABI.
2727 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
2728 // of the section to create, DESCSZ is the size of the descriptor.
2729 // ALLOCATE is true if the section should be allocated in memory.
2730 // This returns the new note section. It sets *TRAILING_PADDING to
2731 // the number of trailing zero bytes required.
2734 Layout::create_note(const char* name
, int note_type
,
2735 const char* section_name
, size_t descsz
,
2736 bool allocate
, size_t* trailing_padding
)
2738 // Authorities all agree that the values in a .note field should
2739 // be aligned on 4-byte boundaries for 32-bit binaries. However,
2740 // they differ on what the alignment is for 64-bit binaries.
2741 // The GABI says unambiguously they take 8-byte alignment:
2742 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
2743 // Other documentation says alignment should always be 4 bytes:
2744 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
2745 // GNU ld and GNU readelf both support the latter (at least as of
2746 // version 2.16.91), and glibc always generates the latter for
2747 // .note.ABI-tag (as of version 1.6), so that's the one we go with
2749 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
2750 const int size
= parameters
->target().get_size();
2752 const int size
= 32;
2755 // The contents of the .note section.
2756 size_t namesz
= strlen(name
) + 1;
2757 size_t aligned_namesz
= align_address(namesz
, size
/ 8);
2758 size_t aligned_descsz
= align_address(descsz
, size
/ 8);
2760 size_t notehdrsz
= 3 * (size
/ 8) + aligned_namesz
;
2762 unsigned char* buffer
= new unsigned char[notehdrsz
];
2763 memset(buffer
, 0, notehdrsz
);
2765 bool is_big_endian
= parameters
->target().is_big_endian();
2771 elfcpp::Swap
<32, false>::writeval(buffer
, namesz
);
2772 elfcpp::Swap
<32, false>::writeval(buffer
+ 4, descsz
);
2773 elfcpp::Swap
<32, false>::writeval(buffer
+ 8, note_type
);
2777 elfcpp::Swap
<32, true>::writeval(buffer
, namesz
);
2778 elfcpp::Swap
<32, true>::writeval(buffer
+ 4, descsz
);
2779 elfcpp::Swap
<32, true>::writeval(buffer
+ 8, note_type
);
2782 else if (size
== 64)
2786 elfcpp::Swap
<64, false>::writeval(buffer
, namesz
);
2787 elfcpp::Swap
<64, false>::writeval(buffer
+ 8, descsz
);
2788 elfcpp::Swap
<64, false>::writeval(buffer
+ 16, note_type
);
2792 elfcpp::Swap
<64, true>::writeval(buffer
, namesz
);
2793 elfcpp::Swap
<64, true>::writeval(buffer
+ 8, descsz
);
2794 elfcpp::Swap
<64, true>::writeval(buffer
+ 16, note_type
);
2800 memcpy(buffer
+ 3 * (size
/ 8), name
, namesz
);
2802 elfcpp::Elf_Xword flags
= 0;
2803 Output_section_order order
= ORDER_INVALID
;
2806 flags
= elfcpp::SHF_ALLOC
;
2807 order
= ORDER_RO_NOTE
;
2809 Output_section
* os
= this->choose_output_section(NULL
, section_name
,
2811 flags
, false, order
, false);
2815 Output_section_data
* posd
= new Output_data_const_buffer(buffer
, notehdrsz
,
2818 os
->add_output_section_data(posd
);
2820 *trailing_padding
= aligned_descsz
- descsz
;
2825 // For an executable or shared library, create a note to record the
2826 // version of gold used to create the binary.
2829 Layout::create_gold_note()
2831 if (parameters
->options().relocatable()
2832 || parameters
->incremental_update())
2835 std::string desc
= std::string("gold ") + gold::get_version_string();
2837 size_t trailing_padding
;
2838 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION
,
2839 ".note.gnu.gold-version", desc
.size(),
2840 false, &trailing_padding
);
2844 Output_section_data
* posd
= new Output_data_const(desc
, 4);
2845 os
->add_output_section_data(posd
);
2847 if (trailing_padding
> 0)
2849 posd
= new Output_data_zero_fill(trailing_padding
, 0);
2850 os
->add_output_section_data(posd
);
2854 // Record whether the stack should be executable. This can be set
2855 // from the command line using the -z execstack or -z noexecstack
2856 // options. Otherwise, if any input file has a .note.GNU-stack
2857 // section with the SHF_EXECINSTR flag set, the stack should be
2858 // executable. Otherwise, if at least one input file a
2859 // .note.GNU-stack section, and some input file has no .note.GNU-stack
2860 // section, we use the target default for whether the stack should be
2861 // executable. Otherwise, we don't generate a stack note. When
2862 // generating a object file, we create a .note.GNU-stack section with
2863 // the appropriate marking. When generating an executable or shared
2864 // library, we create a PT_GNU_STACK segment.
2867 Layout::create_executable_stack_info()
2869 bool is_stack_executable
;
2870 if (parameters
->options().is_execstack_set())
2871 is_stack_executable
= parameters
->options().is_stack_executable();
2872 else if (!this->input_with_gnu_stack_note_
)
2876 if (this->input_requires_executable_stack_
)
2877 is_stack_executable
= true;
2878 else if (this->input_without_gnu_stack_note_
)
2879 is_stack_executable
=
2880 parameters
->target().is_default_stack_executable();
2882 is_stack_executable
= false;
2885 if (parameters
->options().relocatable())
2887 const char* name
= this->namepool_
.add(".note.GNU-stack", false, NULL
);
2888 elfcpp::Elf_Xword flags
= 0;
2889 if (is_stack_executable
)
2890 flags
|= elfcpp::SHF_EXECINSTR
;
2891 this->make_output_section(name
, elfcpp::SHT_PROGBITS
, flags
,
2892 ORDER_INVALID
, false);
2896 if (this->script_options_
->saw_phdrs_clause())
2898 int flags
= elfcpp::PF_R
| elfcpp::PF_W
;
2899 if (is_stack_executable
)
2900 flags
|= elfcpp::PF_X
;
2901 this->make_output_segment(elfcpp::PT_GNU_STACK
, flags
);
2905 // If --build-id was used, set up the build ID note.
2908 Layout::create_build_id()
2910 if (!parameters
->options().user_set_build_id())
2913 const char* style
= parameters
->options().build_id();
2914 if (strcmp(style
, "none") == 0)
2917 // Set DESCSZ to the size of the note descriptor. When possible,
2918 // set DESC to the note descriptor contents.
2921 if (strcmp(style
, "md5") == 0)
2923 else if (strcmp(style
, "sha1") == 0)
2925 else if (strcmp(style
, "uuid") == 0)
2927 const size_t uuidsz
= 128 / 8;
2929 char buffer
[uuidsz
];
2930 memset(buffer
, 0, uuidsz
);
2932 int descriptor
= open_descriptor(-1, "/dev/urandom", O_RDONLY
);
2934 gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
2938 ssize_t got
= ::read(descriptor
, buffer
, uuidsz
);
2939 release_descriptor(descriptor
, true);
2941 gold_error(_("/dev/urandom: read failed: %s"), strerror(errno
));
2942 else if (static_cast<size_t>(got
) != uuidsz
)
2943 gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
2947 desc
.assign(buffer
, uuidsz
);
2950 else if (strncmp(style
, "0x", 2) == 0)
2953 const char* p
= style
+ 2;
2956 if (hex_p(p
[0]) && hex_p(p
[1]))
2958 char c
= (hex_value(p
[0]) << 4) | hex_value(p
[1]);
2962 else if (*p
== '-' || *p
== ':')
2965 gold_fatal(_("--build-id argument '%s' not a valid hex number"),
2968 descsz
= desc
.size();
2971 gold_fatal(_("unrecognized --build-id argument '%s'"), style
);
2974 size_t trailing_padding
;
2975 Output_section
* os
= this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID
,
2976 ".note.gnu.build-id", descsz
, true,
2983 // We know the value already, so we fill it in now.
2984 gold_assert(desc
.size() == descsz
);
2986 Output_section_data
* posd
= new Output_data_const(desc
, 4);
2987 os
->add_output_section_data(posd
);
2989 if (trailing_padding
!= 0)
2991 posd
= new Output_data_zero_fill(trailing_padding
, 0);
2992 os
->add_output_section_data(posd
);
2997 // We need to compute a checksum after we have completed the
2999 gold_assert(trailing_padding
== 0);
3000 this->build_id_note_
= new Output_data_zero_fill(descsz
, 4);
3001 os
->add_output_section_data(this->build_id_note_
);
3005 // If we have both .stabXX and .stabXXstr sections, then the sh_link
3006 // field of the former should point to the latter. I'm not sure who
3007 // started this, but the GNU linker does it, and some tools depend
3011 Layout::link_stabs_sections()
3013 if (!this->have_stabstr_section_
)
3016 for (Section_list::iterator p
= this->section_list_
.begin();
3017 p
!= this->section_list_
.end();
3020 if ((*p
)->type() != elfcpp::SHT_STRTAB
)
3023 const char* name
= (*p
)->name();
3024 if (strncmp(name
, ".stab", 5) != 0)
3027 size_t len
= strlen(name
);
3028 if (strcmp(name
+ len
- 3, "str") != 0)
3031 std::string
stab_name(name
, len
- 3);
3032 Output_section
* stab_sec
;
3033 stab_sec
= this->find_output_section(stab_name
.c_str());
3034 if (stab_sec
!= NULL
)
3035 stab_sec
->set_link_section(*p
);
3039 // Create .gnu_incremental_inputs and related sections needed
3040 // for the next run of incremental linking to check what has changed.
3043 Layout::create_incremental_info_sections(Symbol_table
* symtab
)
3045 Incremental_inputs
* incr
= this->incremental_inputs_
;
3047 gold_assert(incr
!= NULL
);
3049 // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
3050 incr
->create_data_sections(symtab
);
3052 // Add the .gnu_incremental_inputs section.
3053 const char* incremental_inputs_name
=
3054 this->namepool_
.add(".gnu_incremental_inputs", false, NULL
);
3055 Output_section
* incremental_inputs_os
=
3056 this->make_output_section(incremental_inputs_name
,
3057 elfcpp::SHT_GNU_INCREMENTAL_INPUTS
, 0,
3058 ORDER_INVALID
, false);
3059 incremental_inputs_os
->add_output_section_data(incr
->inputs_section());
3061 // Add the .gnu_incremental_symtab section.
3062 const char* incremental_symtab_name
=
3063 this->namepool_
.add(".gnu_incremental_symtab", false, NULL
);
3064 Output_section
* incremental_symtab_os
=
3065 this->make_output_section(incremental_symtab_name
,
3066 elfcpp::SHT_GNU_INCREMENTAL_SYMTAB
, 0,
3067 ORDER_INVALID
, false);
3068 incremental_symtab_os
->add_output_section_data(incr
->symtab_section());
3069 incremental_symtab_os
->set_entsize(4);
3071 // Add the .gnu_incremental_relocs section.
3072 const char* incremental_relocs_name
=
3073 this->namepool_
.add(".gnu_incremental_relocs", false, NULL
);
3074 Output_section
* incremental_relocs_os
=
3075 this->make_output_section(incremental_relocs_name
,
3076 elfcpp::SHT_GNU_INCREMENTAL_RELOCS
, 0,
3077 ORDER_INVALID
, false);
3078 incremental_relocs_os
->add_output_section_data(incr
->relocs_section());
3079 incremental_relocs_os
->set_entsize(incr
->relocs_entsize());
3081 // Add the .gnu_incremental_got_plt section.
3082 const char* incremental_got_plt_name
=
3083 this->namepool_
.add(".gnu_incremental_got_plt", false, NULL
);
3084 Output_section
* incremental_got_plt_os
=
3085 this->make_output_section(incremental_got_plt_name
,
3086 elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT
, 0,
3087 ORDER_INVALID
, false);
3088 incremental_got_plt_os
->add_output_section_data(incr
->got_plt_section());
3090 // Add the .gnu_incremental_strtab section.
3091 const char* incremental_strtab_name
=
3092 this->namepool_
.add(".gnu_incremental_strtab", false, NULL
);
3093 Output_section
* incremental_strtab_os
= this->make_output_section(incremental_strtab_name
,
3094 elfcpp::SHT_STRTAB
, 0,
3095 ORDER_INVALID
, false);
3096 Output_data_strtab
* strtab_data
=
3097 new Output_data_strtab(incr
->get_stringpool());
3098 incremental_strtab_os
->add_output_section_data(strtab_data
);
3100 incremental_inputs_os
->set_after_input_sections();
3101 incremental_symtab_os
->set_after_input_sections();
3102 incremental_relocs_os
->set_after_input_sections();
3103 incremental_got_plt_os
->set_after_input_sections();
3105 incremental_inputs_os
->set_link_section(incremental_strtab_os
);
3106 incremental_symtab_os
->set_link_section(incremental_inputs_os
);
3107 incremental_relocs_os
->set_link_section(incremental_inputs_os
);
3108 incremental_got_plt_os
->set_link_section(incremental_inputs_os
);
3111 // Return whether SEG1 should be before SEG2 in the output file. This
3112 // is based entirely on the segment type and flags. When this is
3113 // called the segment addresses have normally not yet been set.
3116 Layout::segment_precedes(const Output_segment
* seg1
,
3117 const Output_segment
* seg2
)
3119 elfcpp::Elf_Word type1
= seg1
->type();
3120 elfcpp::Elf_Word type2
= seg2
->type();
3122 // The single PT_PHDR segment is required to precede any loadable
3123 // segment. We simply make it always first.
3124 if (type1
== elfcpp::PT_PHDR
)
3126 gold_assert(type2
!= elfcpp::PT_PHDR
);
3129 if (type2
== elfcpp::PT_PHDR
)
3132 // The single PT_INTERP segment is required to precede any loadable
3133 // segment. We simply make it always second.
3134 if (type1
== elfcpp::PT_INTERP
)
3136 gold_assert(type2
!= elfcpp::PT_INTERP
);
3139 if (type2
== elfcpp::PT_INTERP
)
3142 // We then put PT_LOAD segments before any other segments.
3143 if (type1
== elfcpp::PT_LOAD
&& type2
!= elfcpp::PT_LOAD
)
3145 if (type2
== elfcpp::PT_LOAD
&& type1
!= elfcpp::PT_LOAD
)
3148 // We put the PT_TLS segment last except for the PT_GNU_RELRO
3149 // segment, because that is where the dynamic linker expects to find
3150 // it (this is just for efficiency; other positions would also work
3152 if (type1
== elfcpp::PT_TLS
3153 && type2
!= elfcpp::PT_TLS
3154 && type2
!= elfcpp::PT_GNU_RELRO
)
3156 if (type2
== elfcpp::PT_TLS
3157 && type1
!= elfcpp::PT_TLS
3158 && type1
!= elfcpp::PT_GNU_RELRO
)
3161 // We put the PT_GNU_RELRO segment last, because that is where the
3162 // dynamic linker expects to find it (as with PT_TLS, this is just
3164 if (type1
== elfcpp::PT_GNU_RELRO
&& type2
!= elfcpp::PT_GNU_RELRO
)
3166 if (type2
== elfcpp::PT_GNU_RELRO
&& type1
!= elfcpp::PT_GNU_RELRO
)
3169 const elfcpp::Elf_Word flags1
= seg1
->flags();
3170 const elfcpp::Elf_Word flags2
= seg2
->flags();
3172 // The order of non-PT_LOAD segments is unimportant. We simply sort
3173 // by the numeric segment type and flags values. There should not
3174 // be more than one segment with the same type and flags.
3175 if (type1
!= elfcpp::PT_LOAD
)
3178 return type1
< type2
;
3179 gold_assert(flags1
!= flags2
);
3180 return flags1
< flags2
;
3183 // If the addresses are set already, sort by load address.
3184 if (seg1
->are_addresses_set())
3186 if (!seg2
->are_addresses_set())
3189 unsigned int section_count1
= seg1
->output_section_count();
3190 unsigned int section_count2
= seg2
->output_section_count();
3191 if (section_count1
== 0 && section_count2
> 0)
3193 if (section_count1
> 0 && section_count2
== 0)
3196 uint64_t paddr1
= (seg1
->are_addresses_set()
3198 : seg1
->first_section_load_address());
3199 uint64_t paddr2
= (seg2
->are_addresses_set()
3201 : seg2
->first_section_load_address());
3203 if (paddr1
!= paddr2
)
3204 return paddr1
< paddr2
;
3206 else if (seg2
->are_addresses_set())
3209 // A segment which holds large data comes after a segment which does
3210 // not hold large data.
3211 if (seg1
->is_large_data_segment())
3213 if (!seg2
->is_large_data_segment())
3216 else if (seg2
->is_large_data_segment())
3219 // Otherwise, we sort PT_LOAD segments based on the flags. Readonly
3220 // segments come before writable segments. Then writable segments
3221 // with data come before writable segments without data. Then
3222 // executable segments come before non-executable segments. Then
3223 // the unlikely case of a non-readable segment comes before the
3224 // normal case of a readable segment. If there are multiple
3225 // segments with the same type and flags, we require that the
3226 // address be set, and we sort by virtual address and then physical
3228 if ((flags1
& elfcpp::PF_W
) != (flags2
& elfcpp::PF_W
))
3229 return (flags1
& elfcpp::PF_W
) == 0;
3230 if ((flags1
& elfcpp::PF_W
) != 0
3231 && seg1
->has_any_data_sections() != seg2
->has_any_data_sections())
3232 return seg1
->has_any_data_sections();
3233 if ((flags1
& elfcpp::PF_X
) != (flags2
& elfcpp::PF_X
))
3234 return (flags1
& elfcpp::PF_X
) != 0;
3235 if ((flags1
& elfcpp::PF_R
) != (flags2
& elfcpp::PF_R
))
3236 return (flags1
& elfcpp::PF_R
) == 0;
3238 // We shouldn't get here--we shouldn't create segments which we
3239 // can't distinguish. Unless of course we are using a weird linker
3240 // script or overlapping --section-start options. We could also get
3241 // here if plugins want unique segments for subsets of sections.
3242 gold_assert(this->script_options_
->saw_phdrs_clause()
3243 || parameters
->options().any_section_start()
3244 || this->is_unique_segment_for_sections_specified());
3248 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
3251 align_file_offset(off_t off
, uint64_t addr
, uint64_t abi_pagesize
)
3253 uint64_t unsigned_off
= off
;
3254 uint64_t aligned_off
= ((unsigned_off
& ~(abi_pagesize
- 1))
3255 | (addr
& (abi_pagesize
- 1)));
3256 if (aligned_off
< unsigned_off
)
3257 aligned_off
+= abi_pagesize
;
3261 // Set the file offsets of all the segments, and all the sections they
3262 // contain. They have all been created. LOAD_SEG must be be laid out
3263 // first. Return the offset of the data to follow.
3266 Layout::set_segment_offsets(const Target
* target
, Output_segment
* load_seg
,
3267 unsigned int* pshndx
)
3269 // Sort them into the final order. We use a stable sort so that we
3270 // don't randomize the order of indistinguishable segments created
3271 // by linker scripts.
3272 std::stable_sort(this->segment_list_
.begin(), this->segment_list_
.end(),
3273 Layout::Compare_segments(this));
3275 // Find the PT_LOAD segments, and set their addresses and offsets
3276 // and their section's addresses and offsets.
3277 uint64_t start_addr
;
3278 if (parameters
->options().user_set_Ttext())
3279 start_addr
= parameters
->options().Ttext();
3280 else if (parameters
->options().output_is_position_independent())
3283 start_addr
= target
->default_text_segment_address();
3285 uint64_t addr
= start_addr
;
3288 // If LOAD_SEG is NULL, then the file header and segment headers
3289 // will not be loadable. But they still need to be at offset 0 in
3290 // the file. Set their offsets now.
3291 if (load_seg
== NULL
)
3293 for (Data_list::iterator p
= this->special_output_list_
.begin();
3294 p
!= this->special_output_list_
.end();
3297 off
= align_address(off
, (*p
)->addralign());
3298 (*p
)->set_address_and_file_offset(0, off
);
3299 off
+= (*p
)->data_size();
3303 unsigned int increase_relro
= this->increase_relro_
;
3304 if (this->script_options_
->saw_sections_clause())
3307 const bool check_sections
= parameters
->options().check_sections();
3308 Output_segment
* last_load_segment
= NULL
;
3310 unsigned int shndx_begin
= *pshndx
;
3311 unsigned int shndx_load_seg
= *pshndx
;
3313 for (Segment_list::iterator p
= this->segment_list_
.begin();
3314 p
!= this->segment_list_
.end();
3317 if ((*p
)->type() == elfcpp::PT_LOAD
)
3319 if (target
->isolate_execinstr())
3321 // When we hit the segment that should contain the
3322 // file headers, reset the file offset so we place
3323 // it and subsequent segments appropriately.
3324 // We'll fix up the preceding segments below.
3332 shndx_load_seg
= *pshndx
;
3338 // Verify that the file headers fall into the first segment.
3339 if (load_seg
!= NULL
&& load_seg
!= *p
)
3344 bool are_addresses_set
= (*p
)->are_addresses_set();
3345 if (are_addresses_set
)
3347 // When it comes to setting file offsets, we care about
3348 // the physical address.
3349 addr
= (*p
)->paddr();
3351 else if (parameters
->options().user_set_Ttext()
3352 && ((*p
)->flags() & elfcpp::PF_W
) == 0)
3354 are_addresses_set
= true;
3356 else if (parameters
->options().user_set_Tdata()
3357 && ((*p
)->flags() & elfcpp::PF_W
) != 0
3358 && (!parameters
->options().user_set_Tbss()
3359 || (*p
)->has_any_data_sections()))
3361 addr
= parameters
->options().Tdata();
3362 are_addresses_set
= true;
3364 else if (parameters
->options().user_set_Tbss()
3365 && ((*p
)->flags() & elfcpp::PF_W
) != 0
3366 && !(*p
)->has_any_data_sections())
3368 addr
= parameters
->options().Tbss();
3369 are_addresses_set
= true;
3372 uint64_t orig_addr
= addr
;
3373 uint64_t orig_off
= off
;
3375 uint64_t aligned_addr
= 0;
3376 uint64_t abi_pagesize
= target
->abi_pagesize();
3377 uint64_t common_pagesize
= target
->common_pagesize();
3379 if (!parameters
->options().nmagic()
3380 && !parameters
->options().omagic())
3381 (*p
)->set_minimum_p_align(abi_pagesize
);
3383 if (!are_addresses_set
)
3385 // Skip the address forward one page, maintaining the same
3386 // position within the page. This lets us store both segments
3387 // overlapping on a single page in the file, but the loader will
3388 // put them on different pages in memory. We will revisit this
3389 // decision once we know the size of the segment.
3391 addr
= align_address(addr
, (*p
)->maximum_alignment());
3392 aligned_addr
= addr
;
3396 // This is the segment that will contain the file
3397 // headers, so its offset will have to be exactly zero.
3398 gold_assert(orig_off
== 0);
3400 // If the target wants a fixed minimum distance from the
3401 // text segment to the read-only segment, move up now.
3402 uint64_t min_addr
= start_addr
+ target
->rosegment_gap();
3403 if (addr
< min_addr
)
3406 // But this is not the first segment! To make its
3407 // address congruent with its offset, that address better
3408 // be aligned to the ABI-mandated page size.
3409 addr
= align_address(addr
, abi_pagesize
);
3410 aligned_addr
= addr
;
3414 if ((addr
& (abi_pagesize
- 1)) != 0)
3415 addr
= addr
+ abi_pagesize
;
3417 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
3421 if (!parameters
->options().nmagic()
3422 && !parameters
->options().omagic())
3423 off
= align_file_offset(off
, addr
, abi_pagesize
);
3426 // This is -N or -n with a section script which prevents
3427 // us from using a load segment. We need to ensure that
3428 // the file offset is aligned to the alignment of the
3429 // segment. This is because the linker script
3430 // implicitly assumed a zero offset. If we don't align
3431 // here, then the alignment of the sections in the
3432 // linker script may not match the alignment of the
3433 // sections in the set_section_addresses call below,
3434 // causing an error about dot moving backward.
3435 off
= align_address(off
, (*p
)->maximum_alignment());
3438 unsigned int shndx_hold
= *pshndx
;
3439 bool has_relro
= false;
3440 uint64_t new_addr
= (*p
)->set_section_addresses(this, false, addr
,
3445 // Now that we know the size of this segment, we may be able
3446 // to save a page in memory, at the cost of wasting some
3447 // file space, by instead aligning to the start of a new
3448 // page. Here we use the real machine page size rather than
3449 // the ABI mandated page size. If the segment has been
3450 // aligned so that the relro data ends at a page boundary,
3451 // we do not try to realign it.
3453 if (!are_addresses_set
3455 && aligned_addr
!= addr
3456 && !parameters
->incremental())
3458 uint64_t first_off
= (common_pagesize
3460 & (common_pagesize
- 1)));
3461 uint64_t last_off
= new_addr
& (common_pagesize
- 1);
3464 && ((aligned_addr
& ~ (common_pagesize
- 1))
3465 != (new_addr
& ~ (common_pagesize
- 1)))
3466 && first_off
+ last_off
<= common_pagesize
)
3468 *pshndx
= shndx_hold
;
3469 addr
= align_address(aligned_addr
, common_pagesize
);
3470 addr
= align_address(addr
, (*p
)->maximum_alignment());
3471 if ((addr
& (abi_pagesize
- 1)) != 0)
3472 addr
= addr
+ abi_pagesize
;
3473 off
= orig_off
+ ((addr
- orig_addr
) & (abi_pagesize
- 1));
3474 off
= align_file_offset(off
, addr
, abi_pagesize
);
3476 increase_relro
= this->increase_relro_
;
3477 if (this->script_options_
->saw_sections_clause())
3481 new_addr
= (*p
)->set_section_addresses(this, true, addr
,
3490 // Implement --check-sections. We know that the segments
3491 // are sorted by LMA.
3492 if (check_sections
&& last_load_segment
!= NULL
)
3494 gold_assert(last_load_segment
->paddr() <= (*p
)->paddr());
3495 if (last_load_segment
->paddr() + last_load_segment
->memsz()
3498 unsigned long long lb1
= last_load_segment
->paddr();
3499 unsigned long long le1
= lb1
+ last_load_segment
->memsz();
3500 unsigned long long lb2
= (*p
)->paddr();
3501 unsigned long long le2
= lb2
+ (*p
)->memsz();
3502 gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
3503 "[0x%llx -> 0x%llx]"),
3504 lb1
, le1
, lb2
, le2
);
3507 last_load_segment
= *p
;
3511 if (load_seg
!= NULL
&& target
->isolate_execinstr())
3513 // Process the early segments again, setting their file offsets
3514 // so they land after the segments starting at LOAD_SEG.
3515 off
= align_file_offset(off
, 0, target
->abi_pagesize());
3517 for (Segment_list::iterator p
= this->segment_list_
.begin();
3521 if ((*p
)->type() == elfcpp::PT_LOAD
)
3523 // We repeat the whole job of assigning addresses and
3524 // offsets, but we really only want to change the offsets and
3525 // must ensure that the addresses all come out the same as
3526 // they did the first time through.
3527 bool has_relro
= false;
3528 const uint64_t old_addr
= (*p
)->vaddr();
3529 const uint64_t old_end
= old_addr
+ (*p
)->memsz();
3530 uint64_t new_addr
= (*p
)->set_section_addresses(this, true,
3536 gold_assert(new_addr
== old_end
);
3540 gold_assert(shndx_begin
== shndx_load_seg
);
3543 // Handle the non-PT_LOAD segments, setting their offsets from their
3544 // section's offsets.
3545 for (Segment_list::iterator p
= this->segment_list_
.begin();
3546 p
!= this->segment_list_
.end();
3549 if ((*p
)->type() != elfcpp::PT_LOAD
)
3550 (*p
)->set_offset((*p
)->type() == elfcpp::PT_GNU_RELRO
3555 // Set the TLS offsets for each section in the PT_TLS segment.
3556 if (this->tls_segment_
!= NULL
)
3557 this->tls_segment_
->set_tls_offsets();
3562 // Set the offsets of all the allocated sections when doing a
3563 // relocatable link. This does the same jobs as set_segment_offsets,
3564 // only for a relocatable link.
3567 Layout::set_relocatable_section_offsets(Output_data
* file_header
,
3568 unsigned int* pshndx
)
3572 file_header
->set_address_and_file_offset(0, 0);
3573 off
+= file_header
->data_size();
3575 for (Section_list::iterator p
= this->section_list_
.begin();
3576 p
!= this->section_list_
.end();
3579 // We skip unallocated sections here, except that group sections
3580 // have to come first.
3581 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) == 0
3582 && (*p
)->type() != elfcpp::SHT_GROUP
)
3585 off
= align_address(off
, (*p
)->addralign());
3587 // The linker script might have set the address.
3588 if (!(*p
)->is_address_valid())
3589 (*p
)->set_address(0);
3590 (*p
)->set_file_offset(off
);
3591 (*p
)->finalize_data_size();
3592 off
+= (*p
)->data_size();
3594 (*p
)->set_out_shndx(*pshndx
);
3601 // Set the file offset of all the sections not associated with a
3605 Layout::set_section_offsets(off_t off
, Layout::Section_offset_pass pass
)
3607 off_t startoff
= off
;
3610 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
3611 p
!= this->unattached_section_list_
.end();
3614 // The symtab section is handled in create_symtab_sections.
3615 if (*p
== this->symtab_section_
)
3618 // If we've already set the data size, don't set it again.
3619 if ((*p
)->is_offset_valid() && (*p
)->is_data_size_valid())
3622 if (pass
== BEFORE_INPUT_SECTIONS_PASS
3623 && (*p
)->requires_postprocessing())
3625 (*p
)->create_postprocessing_buffer();
3626 this->any_postprocessing_sections_
= true;
3629 if (pass
== BEFORE_INPUT_SECTIONS_PASS
3630 && (*p
)->after_input_sections())
3632 else if (pass
== POSTPROCESSING_SECTIONS_PASS
3633 && (!(*p
)->after_input_sections()
3634 || (*p
)->type() == elfcpp::SHT_STRTAB
))
3636 else if (pass
== STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
3637 && (!(*p
)->after_input_sections()
3638 || (*p
)->type() != elfcpp::SHT_STRTAB
))
3641 if (!parameters
->incremental_update())
3643 off
= align_address(off
, (*p
)->addralign());
3644 (*p
)->set_file_offset(off
);
3645 (*p
)->finalize_data_size();
3649 // Incremental update: allocate file space from free list.
3650 (*p
)->pre_finalize_data_size();
3651 off_t current_size
= (*p
)->current_data_size();
3652 off
= this->allocate(current_size
, (*p
)->addralign(), startoff
);
3655 if (is_debugging_enabled(DEBUG_INCREMENTAL
))
3656 this->free_list_
.dump();
3657 gold_assert((*p
)->output_section() != NULL
);
3658 gold_fallback(_("out of patch space for section %s; "
3659 "relink with --incremental-full"),
3660 (*p
)->output_section()->name());
3662 (*p
)->set_file_offset(off
);
3663 (*p
)->finalize_data_size();
3664 if ((*p
)->data_size() > current_size
)
3666 gold_assert((*p
)->output_section() != NULL
);
3667 gold_fallback(_("%s: section changed size; "
3668 "relink with --incremental-full"),
3669 (*p
)->output_section()->name());
3671 gold_debug(DEBUG_INCREMENTAL
,
3672 "set_section_offsets: %08lx %08lx %s",
3673 static_cast<long>(off
),
3674 static_cast<long>((*p
)->data_size()),
3675 ((*p
)->output_section() != NULL
3676 ? (*p
)->output_section()->name() : "(special)"));
3679 off
+= (*p
)->data_size();
3683 // At this point the name must be set.
3684 if (pass
!= STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
)
3685 this->namepool_
.add((*p
)->name(), false, NULL
);
3690 // Set the section indexes of all the sections not associated with a
3694 Layout::set_section_indexes(unsigned int shndx
)
3696 for (Section_list::iterator p
= this->unattached_section_list_
.begin();
3697 p
!= this->unattached_section_list_
.end();
3700 if (!(*p
)->has_out_shndx())
3702 (*p
)->set_out_shndx(shndx
);
3709 // Set the section addresses according to the linker script. This is
3710 // only called when we see a SECTIONS clause. This returns the
3711 // program segment which should hold the file header and segment
3712 // headers, if any. It will return NULL if they should not be in a
3716 Layout::set_section_addresses_from_script(Symbol_table
* symtab
)
3718 Script_sections
* ss
= this->script_options_
->script_sections();
3719 gold_assert(ss
->saw_sections_clause());
3720 return this->script_options_
->set_section_addresses(symtab
, this);
3723 // Place the orphan sections in the linker script.
3726 Layout::place_orphan_sections_in_script()
3728 Script_sections
* ss
= this->script_options_
->script_sections();
3729 gold_assert(ss
->saw_sections_clause());
3731 // Place each orphaned output section in the script.
3732 for (Section_list::iterator p
= this->section_list_
.begin();
3733 p
!= this->section_list_
.end();
3736 if (!(*p
)->found_in_sections_clause())
3737 ss
->place_orphan(*p
);
3741 // Count the local symbols in the regular symbol table and the dynamic
3742 // symbol table, and build the respective string pools.
3745 Layout::count_local_symbols(const Task
* task
,
3746 const Input_objects
* input_objects
)
3748 // First, figure out an upper bound on the number of symbols we'll
3749 // be inserting into each pool. This helps us create the pools with
3750 // the right size, to avoid unnecessary hashtable resizing.
3751 unsigned int symbol_count
= 0;
3752 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3753 p
!= input_objects
->relobj_end();
3755 symbol_count
+= (*p
)->local_symbol_count();
3757 // Go from "upper bound" to "estimate." We overcount for two
3758 // reasons: we double-count symbols that occur in more than one
3759 // object file, and we count symbols that are dropped from the
3760 // output. Add it all together and assume we overcount by 100%.
3763 // We assume all symbols will go into both the sympool and dynpool.
3764 this->sympool_
.reserve(symbol_count
);
3765 this->dynpool_
.reserve(symbol_count
);
3767 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3768 p
!= input_objects
->relobj_end();
3771 Task_lock_obj
<Object
> tlo(task
, *p
);
3772 (*p
)->count_local_symbols(&this->sympool_
, &this->dynpool_
);
3776 // Create the symbol table sections. Here we also set the final
3777 // values of the symbols. At this point all the loadable sections are
3778 // fully laid out. SHNUM is the number of sections so far.
3781 Layout::create_symtab_sections(const Input_objects
* input_objects
,
3782 Symbol_table
* symtab
,
3788 if (parameters
->target().get_size() == 32)
3790 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
3793 else if (parameters
->target().get_size() == 64)
3795 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
3801 // Compute file offsets relative to the start of the symtab section.
3804 // Save space for the dummy symbol at the start of the section. We
3805 // never bother to write this out--it will just be left as zero.
3807 unsigned int local_symbol_index
= 1;
3809 // Add STT_SECTION symbols for each Output section which needs one.
3810 for (Section_list::iterator p
= this->section_list_
.begin();
3811 p
!= this->section_list_
.end();
3814 if (!(*p
)->needs_symtab_index())
3815 (*p
)->set_symtab_index(-1U);
3818 (*p
)->set_symtab_index(local_symbol_index
);
3819 ++local_symbol_index
;
3824 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
3825 p
!= input_objects
->relobj_end();
3828 unsigned int index
= (*p
)->finalize_local_symbols(local_symbol_index
,
3830 off
+= (index
- local_symbol_index
) * symsize
;
3831 local_symbol_index
= index
;
3834 unsigned int local_symcount
= local_symbol_index
;
3835 gold_assert(static_cast<off_t
>(local_symcount
* symsize
) == off
);
3838 size_t dyn_global_index
;
3840 if (this->dynsym_section_
== NULL
)
3843 dyn_global_index
= 0;
3848 dyn_global_index
= this->dynsym_section_
->info();
3849 off_t locsize
= dyn_global_index
* this->dynsym_section_
->entsize();
3850 dynoff
= this->dynsym_section_
->offset() + locsize
;
3851 dyncount
= (this->dynsym_section_
->data_size() - locsize
) / symsize
;
3852 gold_assert(static_cast<off_t
>(dyncount
* symsize
)
3853 == this->dynsym_section_
->data_size() - locsize
);
3856 off_t global_off
= off
;
3857 off
= symtab
->finalize(off
, dynoff
, dyn_global_index
, dyncount
,
3858 &this->sympool_
, &local_symcount
);
3860 if (!parameters
->options().strip_all())
3862 this->sympool_
.set_string_offsets();
3864 const char* symtab_name
= this->namepool_
.add(".symtab", false, NULL
);
3865 Output_section
* osymtab
= this->make_output_section(symtab_name
,
3869 this->symtab_section_
= osymtab
;
3871 Output_section_data
* pos
= new Output_data_fixed_space(off
, align
,
3873 osymtab
->add_output_section_data(pos
);
3875 // We generate a .symtab_shndx section if we have more than
3876 // SHN_LORESERVE sections. Technically it is possible that we
3877 // don't need one, because it is possible that there are no
3878 // symbols in any of sections with indexes larger than
3879 // SHN_LORESERVE. That is probably unusual, though, and it is
3880 // easier to always create one than to compute section indexes
3881 // twice (once here, once when writing out the symbols).
3882 if (shnum
>= elfcpp::SHN_LORESERVE
)
3884 const char* symtab_xindex_name
= this->namepool_
.add(".symtab_shndx",
3886 Output_section
* osymtab_xindex
=
3887 this->make_output_section(symtab_xindex_name
,
3888 elfcpp::SHT_SYMTAB_SHNDX
, 0,
3889 ORDER_INVALID
, false);
3891 size_t symcount
= off
/ symsize
;
3892 this->symtab_xindex_
= new Output_symtab_xindex(symcount
);
3894 osymtab_xindex
->add_output_section_data(this->symtab_xindex_
);
3896 osymtab_xindex
->set_link_section(osymtab
);
3897 osymtab_xindex
->set_addralign(4);
3898 osymtab_xindex
->set_entsize(4);
3900 osymtab_xindex
->set_after_input_sections();
3902 // This tells the driver code to wait until the symbol table
3903 // has written out before writing out the postprocessing
3904 // sections, including the .symtab_shndx section.
3905 this->any_postprocessing_sections_
= true;
3908 const char* strtab_name
= this->namepool_
.add(".strtab", false, NULL
);
3909 Output_section
* ostrtab
= this->make_output_section(strtab_name
,
3914 Output_section_data
* pstr
= new Output_data_strtab(&this->sympool_
);
3915 ostrtab
->add_output_section_data(pstr
);
3918 if (!parameters
->incremental_update())
3919 symtab_off
= align_address(*poff
, align
);
3922 symtab_off
= this->allocate(off
, align
, *poff
);
3924 gold_fallback(_("out of patch space for symbol table; "
3925 "relink with --incremental-full"));
3926 gold_debug(DEBUG_INCREMENTAL
,
3927 "create_symtab_sections: %08lx %08lx .symtab",
3928 static_cast<long>(symtab_off
),
3929 static_cast<long>(off
));
3932 symtab
->set_file_offset(symtab_off
+ global_off
);
3933 osymtab
->set_file_offset(symtab_off
);
3934 osymtab
->finalize_data_size();
3935 osymtab
->set_link_section(ostrtab
);
3936 osymtab
->set_info(local_symcount
);
3937 osymtab
->set_entsize(symsize
);
3939 if (symtab_off
+ off
> *poff
)
3940 *poff
= symtab_off
+ off
;
3944 // Create the .shstrtab section, which holds the names of the
3945 // sections. At the time this is called, we have created all the
3946 // output sections except .shstrtab itself.
3949 Layout::create_shstrtab()
3951 // FIXME: We don't need to create a .shstrtab section if we are
3952 // stripping everything.
3954 const char* name
= this->namepool_
.add(".shstrtab", false, NULL
);
3956 Output_section
* os
= this->make_output_section(name
, elfcpp::SHT_STRTAB
, 0,
3957 ORDER_INVALID
, false);
3959 if (strcmp(parameters
->options().compress_debug_sections(), "none") != 0)
3961 // We can't write out this section until we've set all the
3962 // section names, and we don't set the names of compressed
3963 // output sections until relocations are complete. FIXME: With
3964 // the current names we use, this is unnecessary.
3965 os
->set_after_input_sections();
3968 Output_section_data
* posd
= new Output_data_strtab(&this->namepool_
);
3969 os
->add_output_section_data(posd
);
3974 // Create the section headers. SIZE is 32 or 64. OFF is the file
3978 Layout::create_shdrs(const Output_section
* shstrtab_section
, off_t
* poff
)
3980 Output_section_headers
* oshdrs
;
3981 oshdrs
= new Output_section_headers(this,
3982 &this->segment_list_
,
3983 &this->section_list_
,
3984 &this->unattached_section_list_
,
3988 if (!parameters
->incremental_update())
3989 off
= align_address(*poff
, oshdrs
->addralign());
3992 oshdrs
->pre_finalize_data_size();
3993 off
= this->allocate(oshdrs
->data_size(), oshdrs
->addralign(), *poff
);
3995 gold_fallback(_("out of patch space for section header table; "
3996 "relink with --incremental-full"));
3997 gold_debug(DEBUG_INCREMENTAL
,
3998 "create_shdrs: %08lx %08lx (section header table)",
3999 static_cast<long>(off
),
4000 static_cast<long>(off
+ oshdrs
->data_size()));
4002 oshdrs
->set_address_and_file_offset(0, off
);
4003 off
+= oshdrs
->data_size();
4006 this->section_headers_
= oshdrs
;
4009 // Count the allocated sections.
4012 Layout::allocated_output_section_count() const
4014 size_t section_count
= 0;
4015 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4016 p
!= this->segment_list_
.end();
4018 section_count
+= (*p
)->output_section_count();
4019 return section_count
;
4022 // Create the dynamic symbol table.
4025 Layout::create_dynamic_symtab(const Input_objects
* input_objects
,
4026 Symbol_table
* symtab
,
4027 Output_section
** pdynstr
,
4028 unsigned int* plocal_dynamic_count
,
4029 std::vector
<Symbol
*>* pdynamic_symbols
,
4030 Versions
* pversions
)
4032 // Count all the symbols in the dynamic symbol table, and set the
4033 // dynamic symbol indexes.
4035 // Skip symbol 0, which is always all zeroes.
4036 unsigned int index
= 1;
4038 // Add STT_SECTION symbols for each Output section which needs one.
4039 for (Section_list::iterator p
= this->section_list_
.begin();
4040 p
!= this->section_list_
.end();
4043 if (!(*p
)->needs_dynsym_index())
4044 (*p
)->set_dynsym_index(-1U);
4047 (*p
)->set_dynsym_index(index
);
4052 // Count the local symbols that need to go in the dynamic symbol table,
4053 // and set the dynamic symbol indexes.
4054 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4055 p
!= input_objects
->relobj_end();
4058 unsigned int new_index
= (*p
)->set_local_dynsym_indexes(index
);
4062 unsigned int local_symcount
= index
;
4063 *plocal_dynamic_count
= local_symcount
;
4065 index
= symtab
->set_dynsym_indexes(index
, pdynamic_symbols
,
4066 &this->dynpool_
, pversions
);
4070 const int size
= parameters
->target().get_size();
4073 symsize
= elfcpp::Elf_sizes
<32>::sym_size
;
4076 else if (size
== 64)
4078 symsize
= elfcpp::Elf_sizes
<64>::sym_size
;
4084 // Create the dynamic symbol table section.
4086 Output_section
* dynsym
= this->choose_output_section(NULL
, ".dynsym",
4090 ORDER_DYNAMIC_LINKER
,
4093 // Check for NULL as a linker script may discard .dynsym.
4096 Output_section_data
* odata
= new Output_data_fixed_space(index
* symsize
,
4099 dynsym
->add_output_section_data(odata
);
4101 dynsym
->set_info(local_symcount
);
4102 dynsym
->set_entsize(symsize
);
4103 dynsym
->set_addralign(align
);
4105 this->dynsym_section_
= dynsym
;
4108 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4111 odyn
->add_section_address(elfcpp::DT_SYMTAB
, dynsym
);
4112 odyn
->add_constant(elfcpp::DT_SYMENT
, symsize
);
4115 // If there are more than SHN_LORESERVE allocated sections, we
4116 // create a .dynsym_shndx section. It is possible that we don't
4117 // need one, because it is possible that there are no dynamic
4118 // symbols in any of the sections with indexes larger than
4119 // SHN_LORESERVE. This is probably unusual, though, and at this
4120 // time we don't know the actual section indexes so it is
4121 // inconvenient to check.
4122 if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE
)
4124 Output_section
* dynsym_xindex
=
4125 this->choose_output_section(NULL
, ".dynsym_shndx",
4126 elfcpp::SHT_SYMTAB_SHNDX
,
4128 false, ORDER_DYNAMIC_LINKER
, false);
4130 if (dynsym_xindex
!= NULL
)
4132 this->dynsym_xindex_
= new Output_symtab_xindex(index
);
4134 dynsym_xindex
->add_output_section_data(this->dynsym_xindex_
);
4136 dynsym_xindex
->set_link_section(dynsym
);
4137 dynsym_xindex
->set_addralign(4);
4138 dynsym_xindex
->set_entsize(4);
4140 dynsym_xindex
->set_after_input_sections();
4142 // This tells the driver code to wait until the symbol table
4143 // has written out before writing out the postprocessing
4144 // sections, including the .dynsym_shndx section.
4145 this->any_postprocessing_sections_
= true;
4149 // Create the dynamic string table section.
4151 Output_section
* dynstr
= this->choose_output_section(NULL
, ".dynstr",
4155 ORDER_DYNAMIC_LINKER
,
4160 Output_section_data
* strdata
= new Output_data_strtab(&this->dynpool_
);
4161 dynstr
->add_output_section_data(strdata
);
4164 dynsym
->set_link_section(dynstr
);
4165 if (this->dynamic_section_
!= NULL
)
4166 this->dynamic_section_
->set_link_section(dynstr
);
4170 odyn
->add_section_address(elfcpp::DT_STRTAB
, dynstr
);
4171 odyn
->add_section_size(elfcpp::DT_STRSZ
, dynstr
);
4177 // Create the hash tables.
4179 if (strcmp(parameters
->options().hash_style(), "sysv") == 0
4180 || strcmp(parameters
->options().hash_style(), "both") == 0)
4182 unsigned char* phash
;
4183 unsigned int hashlen
;
4184 Dynobj::create_elf_hash_table(*pdynamic_symbols
, local_symcount
,
4187 Output_section
* hashsec
=
4188 this->choose_output_section(NULL
, ".hash", elfcpp::SHT_HASH
,
4189 elfcpp::SHF_ALLOC
, false,
4190 ORDER_DYNAMIC_LINKER
, false);
4192 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
4196 if (hashsec
!= NULL
&& hashdata
!= NULL
)
4197 hashsec
->add_output_section_data(hashdata
);
4199 if (hashsec
!= NULL
)
4202 hashsec
->set_link_section(dynsym
);
4203 hashsec
->set_entsize(4);
4207 odyn
->add_section_address(elfcpp::DT_HASH
, hashsec
);
4210 if (strcmp(parameters
->options().hash_style(), "gnu") == 0
4211 || strcmp(parameters
->options().hash_style(), "both") == 0)
4213 unsigned char* phash
;
4214 unsigned int hashlen
;
4215 Dynobj::create_gnu_hash_table(*pdynamic_symbols
, local_symcount
,
4218 Output_section
* hashsec
=
4219 this->choose_output_section(NULL
, ".gnu.hash", elfcpp::SHT_GNU_HASH
,
4220 elfcpp::SHF_ALLOC
, false,
4221 ORDER_DYNAMIC_LINKER
, false);
4223 Output_section_data
* hashdata
= new Output_data_const_buffer(phash
,
4227 if (hashsec
!= NULL
&& hashdata
!= NULL
)
4228 hashsec
->add_output_section_data(hashdata
);
4230 if (hashsec
!= NULL
)
4233 hashsec
->set_link_section(dynsym
);
4235 // For a 64-bit target, the entries in .gnu.hash do not have
4236 // a uniform size, so we only set the entry size for a
4238 if (parameters
->target().get_size() == 32)
4239 hashsec
->set_entsize(4);
4242 odyn
->add_section_address(elfcpp::DT_GNU_HASH
, hashsec
);
4247 // Assign offsets to each local portion of the dynamic symbol table.
4250 Layout::assign_local_dynsym_offsets(const Input_objects
* input_objects
)
4252 Output_section
* dynsym
= this->dynsym_section_
;
4256 off_t off
= dynsym
->offset();
4258 // Skip the dummy symbol at the start of the section.
4259 off
+= dynsym
->entsize();
4261 for (Input_objects::Relobj_iterator p
= input_objects
->relobj_begin();
4262 p
!= input_objects
->relobj_end();
4265 unsigned int count
= (*p
)->set_local_dynsym_offset(off
);
4266 off
+= count
* dynsym
->entsize();
4270 // Create the version sections.
4273 Layout::create_version_sections(const Versions
* versions
,
4274 const Symbol_table
* symtab
,
4275 unsigned int local_symcount
,
4276 const std::vector
<Symbol
*>& dynamic_symbols
,
4277 const Output_section
* dynstr
)
4279 if (!versions
->any_defs() && !versions
->any_needs())
4282 switch (parameters
->size_and_endianness())
4284 #ifdef HAVE_TARGET_32_LITTLE
4285 case Parameters::TARGET_32_LITTLE
:
4286 this->sized_create_version_sections
<32, false>(versions
, symtab
,
4288 dynamic_symbols
, dynstr
);
4291 #ifdef HAVE_TARGET_32_BIG
4292 case Parameters::TARGET_32_BIG
:
4293 this->sized_create_version_sections
<32, true>(versions
, symtab
,
4295 dynamic_symbols
, dynstr
);
4298 #ifdef HAVE_TARGET_64_LITTLE
4299 case Parameters::TARGET_64_LITTLE
:
4300 this->sized_create_version_sections
<64, false>(versions
, symtab
,
4302 dynamic_symbols
, dynstr
);
4305 #ifdef HAVE_TARGET_64_BIG
4306 case Parameters::TARGET_64_BIG
:
4307 this->sized_create_version_sections
<64, true>(versions
, symtab
,
4309 dynamic_symbols
, dynstr
);
4317 // Create the version sections, sized version.
4319 template<int size
, bool big_endian
>
4321 Layout::sized_create_version_sections(
4322 const Versions
* versions
,
4323 const Symbol_table
* symtab
,
4324 unsigned int local_symcount
,
4325 const std::vector
<Symbol
*>& dynamic_symbols
,
4326 const Output_section
* dynstr
)
4328 Output_section
* vsec
= this->choose_output_section(NULL
, ".gnu.version",
4329 elfcpp::SHT_GNU_versym
,
4332 ORDER_DYNAMIC_LINKER
,
4335 // Check for NULL since a linker script may discard this section.
4338 unsigned char* vbuf
;
4340 versions
->symbol_section_contents
<size
, big_endian
>(symtab
,
4346 Output_section_data
* vdata
= new Output_data_const_buffer(vbuf
, vsize
, 2,
4349 vsec
->add_output_section_data(vdata
);
4350 vsec
->set_entsize(2);
4351 vsec
->set_link_section(this->dynsym_section_
);
4354 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4355 if (odyn
!= NULL
&& vsec
!= NULL
)
4356 odyn
->add_section_address(elfcpp::DT_VERSYM
, vsec
);
4358 if (versions
->any_defs())
4360 Output_section
* vdsec
;
4361 vdsec
= this->choose_output_section(NULL
, ".gnu.version_d",
4362 elfcpp::SHT_GNU_verdef
,
4364 false, ORDER_DYNAMIC_LINKER
, false);
4368 unsigned char* vdbuf
;
4369 unsigned int vdsize
;
4370 unsigned int vdentries
;
4371 versions
->def_section_contents
<size
, big_endian
>(&this->dynpool_
,
4375 Output_section_data
* vddata
=
4376 new Output_data_const_buffer(vdbuf
, vdsize
, 4, "** version defs");
4378 vdsec
->add_output_section_data(vddata
);
4379 vdsec
->set_link_section(dynstr
);
4380 vdsec
->set_info(vdentries
);
4384 odyn
->add_section_address(elfcpp::DT_VERDEF
, vdsec
);
4385 odyn
->add_constant(elfcpp::DT_VERDEFNUM
, vdentries
);
4390 if (versions
->any_needs())
4392 Output_section
* vnsec
;
4393 vnsec
= this->choose_output_section(NULL
, ".gnu.version_r",
4394 elfcpp::SHT_GNU_verneed
,
4396 false, ORDER_DYNAMIC_LINKER
, false);
4400 unsigned char* vnbuf
;
4401 unsigned int vnsize
;
4402 unsigned int vnentries
;
4403 versions
->need_section_contents
<size
, big_endian
>(&this->dynpool_
,
4407 Output_section_data
* vndata
=
4408 new Output_data_const_buffer(vnbuf
, vnsize
, 4, "** version refs");
4410 vnsec
->add_output_section_data(vndata
);
4411 vnsec
->set_link_section(dynstr
);
4412 vnsec
->set_info(vnentries
);
4416 odyn
->add_section_address(elfcpp::DT_VERNEED
, vnsec
);
4417 odyn
->add_constant(elfcpp::DT_VERNEEDNUM
, vnentries
);
4423 // Create the .interp section and PT_INTERP segment.
4426 Layout::create_interp(const Target
* target
)
4428 gold_assert(this->interp_segment_
== NULL
);
4430 const char* interp
= parameters
->options().dynamic_linker();
4433 interp
= target
->dynamic_linker();
4434 gold_assert(interp
!= NULL
);
4437 size_t len
= strlen(interp
) + 1;
4439 Output_section_data
* odata
= new Output_data_const(interp
, len
, 1);
4441 Output_section
* osec
= this->choose_output_section(NULL
, ".interp",
4442 elfcpp::SHT_PROGBITS
,
4444 false, ORDER_INTERP
,
4447 osec
->add_output_section_data(odata
);
4450 // Add dynamic tags for the PLT and the dynamic relocs. This is
4451 // called by the target-specific code. This does nothing if not doing
4454 // USE_REL is true for REL relocs rather than RELA relocs.
4456 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
4458 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
4459 // and we also set DT_PLTREL. We use PLT_REL's output section, since
4460 // some targets have multiple reloc sections in PLT_REL.
4462 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
4463 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT. Again we use the output
4466 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
4470 Layout::add_target_dynamic_tags(bool use_rel
, const Output_data
* plt_got
,
4471 const Output_data
* plt_rel
,
4472 const Output_data_reloc_generic
* dyn_rel
,
4473 bool add_debug
, bool dynrel_includes_plt
)
4475 Output_data_dynamic
* odyn
= this->dynamic_data_
;
4479 if (plt_got
!= NULL
&& plt_got
->output_section() != NULL
)
4480 odyn
->add_section_address(elfcpp::DT_PLTGOT
, plt_got
);
4482 if (plt_rel
!= NULL
&& plt_rel
->output_section() != NULL
)
4484 odyn
->add_section_size(elfcpp::DT_PLTRELSZ
, plt_rel
->output_section());
4485 odyn
->add_section_address(elfcpp::DT_JMPREL
, plt_rel
->output_section());
4486 odyn
->add_constant(elfcpp::DT_PLTREL
,
4487 use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
);
4490 if ((dyn_rel
!= NULL
&& dyn_rel
->output_section() != NULL
)
4491 || (dynrel_includes_plt
4493 && plt_rel
->output_section() != NULL
))
4495 bool have_dyn_rel
= dyn_rel
!= NULL
&& dyn_rel
->output_section() != NULL
;
4496 bool have_plt_rel
= plt_rel
!= NULL
&& plt_rel
->output_section() != NULL
;
4497 odyn
->add_section_address(use_rel
? elfcpp::DT_REL
: elfcpp::DT_RELA
,
4499 ? dyn_rel
->output_section()
4500 : plt_rel
->output_section()));
4501 elfcpp::DT size_tag
= use_rel
? elfcpp::DT_RELSZ
: elfcpp::DT_RELASZ
;
4502 if (have_dyn_rel
&& have_plt_rel
&& dynrel_includes_plt
)
4503 odyn
->add_section_size(size_tag
,
4504 dyn_rel
->output_section(),
4505 plt_rel
->output_section());
4506 else if (have_dyn_rel
)
4507 odyn
->add_section_size(size_tag
, dyn_rel
->output_section());
4509 odyn
->add_section_size(size_tag
, plt_rel
->output_section());
4510 const int size
= parameters
->target().get_size();
4515 rel_tag
= elfcpp::DT_RELENT
;
4517 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 32, false>::reloc_size
;
4518 else if (size
== 64)
4519 rel_size
= Reloc_types
<elfcpp::SHT_REL
, 64, false>::reloc_size
;
4525 rel_tag
= elfcpp::DT_RELAENT
;
4527 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 32, false>::reloc_size
;
4528 else if (size
== 64)
4529 rel_size
= Reloc_types
<elfcpp::SHT_RELA
, 64, false>::reloc_size
;
4533 odyn
->add_constant(rel_tag
, rel_size
);
4535 if (parameters
->options().combreloc() && have_dyn_rel
)
4537 size_t c
= dyn_rel
->relative_reloc_count();
4539 odyn
->add_constant((use_rel
4540 ? elfcpp::DT_RELCOUNT
4541 : elfcpp::DT_RELACOUNT
),
4546 if (add_debug
&& !parameters
->options().shared())
4548 // The value of the DT_DEBUG tag is filled in by the dynamic
4549 // linker at run time, and used by the debugger.
4550 odyn
->add_constant(elfcpp::DT_DEBUG
, 0);
4554 // Finish the .dynamic section and PT_DYNAMIC segment.
4557 Layout::finish_dynamic_section(const Input_objects
* input_objects
,
4558 const Symbol_table
* symtab
)
4560 if (!this->script_options_
->saw_phdrs_clause()
4561 && this->dynamic_section_
!= NULL
)
4563 Output_segment
* oseg
= this->make_output_segment(elfcpp::PT_DYNAMIC
,
4566 oseg
->add_output_section_to_nonload(this->dynamic_section_
,
4567 elfcpp::PF_R
| elfcpp::PF_W
);
4570 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4574 for (Input_objects::Dynobj_iterator p
= input_objects
->dynobj_begin();
4575 p
!= input_objects
->dynobj_end();
4578 if (!(*p
)->is_needed() && (*p
)->as_needed())
4580 // This dynamic object was linked with --as-needed, but it
4585 odyn
->add_string(elfcpp::DT_NEEDED
, (*p
)->soname());
4588 if (parameters
->options().shared())
4590 const char* soname
= parameters
->options().soname();
4592 odyn
->add_string(elfcpp::DT_SONAME
, soname
);
4595 Symbol
* sym
= symtab
->lookup(parameters
->options().init());
4596 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
4597 odyn
->add_symbol(elfcpp::DT_INIT
, sym
);
4599 sym
= symtab
->lookup(parameters
->options().fini());
4600 if (sym
!= NULL
&& sym
->is_defined() && !sym
->is_from_dynobj())
4601 odyn
->add_symbol(elfcpp::DT_FINI
, sym
);
4603 // Look for .init_array, .preinit_array and .fini_array by checking
4605 for(Layout::Section_list::const_iterator p
= this->section_list_
.begin();
4606 p
!= this->section_list_
.end();
4608 switch((*p
)->type())
4610 case elfcpp::SHT_FINI_ARRAY
:
4611 odyn
->add_section_address(elfcpp::DT_FINI_ARRAY
, *p
);
4612 odyn
->add_section_size(elfcpp::DT_FINI_ARRAYSZ
, *p
);
4614 case elfcpp::SHT_INIT_ARRAY
:
4615 odyn
->add_section_address(elfcpp::DT_INIT_ARRAY
, *p
);
4616 odyn
->add_section_size(elfcpp::DT_INIT_ARRAYSZ
, *p
);
4618 case elfcpp::SHT_PREINIT_ARRAY
:
4619 odyn
->add_section_address(elfcpp::DT_PREINIT_ARRAY
, *p
);
4620 odyn
->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ
, *p
);
4626 // Add a DT_RPATH entry if needed.
4627 const General_options::Dir_list
& rpath(parameters
->options().rpath());
4630 std::string rpath_val
;
4631 for (General_options::Dir_list::const_iterator p
= rpath
.begin();
4635 if (rpath_val
.empty())
4636 rpath_val
= p
->name();
4639 // Eliminate duplicates.
4640 General_options::Dir_list::const_iterator q
;
4641 for (q
= rpath
.begin(); q
!= p
; ++q
)
4642 if (q
->name() == p
->name())
4647 rpath_val
+= p
->name();
4652 if (!parameters
->options().enable_new_dtags())
4653 odyn
->add_string(elfcpp::DT_RPATH
, rpath_val
);
4655 odyn
->add_string(elfcpp::DT_RUNPATH
, rpath_val
);
4658 // Look for text segments that have dynamic relocations.
4659 bool have_textrel
= false;
4660 if (!this->script_options_
->saw_sections_clause())
4662 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
4663 p
!= this->segment_list_
.end();
4666 if ((*p
)->type() == elfcpp::PT_LOAD
4667 && ((*p
)->flags() & elfcpp::PF_W
) == 0
4668 && (*p
)->has_dynamic_reloc())
4670 have_textrel
= true;
4677 // We don't know the section -> segment mapping, so we are
4678 // conservative and just look for readonly sections with
4679 // relocations. If those sections wind up in writable segments,
4680 // then we have created an unnecessary DT_TEXTREL entry.
4681 for (Section_list::const_iterator p
= this->section_list_
.begin();
4682 p
!= this->section_list_
.end();
4685 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0
4686 && ((*p
)->flags() & elfcpp::SHF_WRITE
) == 0
4687 && (*p
)->has_dynamic_reloc())
4689 have_textrel
= true;
4695 if (parameters
->options().filter() != NULL
)
4696 odyn
->add_string(elfcpp::DT_FILTER
, parameters
->options().filter());
4697 if (parameters
->options().any_auxiliary())
4699 for (options::String_set::const_iterator p
=
4700 parameters
->options().auxiliary_begin();
4701 p
!= parameters
->options().auxiliary_end();
4703 odyn
->add_string(elfcpp::DT_AUXILIARY
, *p
);
4706 // Add a DT_FLAGS entry if necessary.
4707 unsigned int flags
= 0;
4710 // Add a DT_TEXTREL for compatibility with older loaders.
4711 odyn
->add_constant(elfcpp::DT_TEXTREL
, 0);
4712 flags
|= elfcpp::DF_TEXTREL
;
4714 if (parameters
->options().text())
4715 gold_error(_("read-only segment has dynamic relocations"));
4716 else if (parameters
->options().warn_shared_textrel()
4717 && parameters
->options().shared())
4718 gold_warning(_("shared library text segment is not shareable"));
4720 if (parameters
->options().shared() && this->has_static_tls())
4721 flags
|= elfcpp::DF_STATIC_TLS
;
4722 if (parameters
->options().origin())
4723 flags
|= elfcpp::DF_ORIGIN
;
4724 if (parameters
->options().Bsymbolic())
4726 flags
|= elfcpp::DF_SYMBOLIC
;
4727 // Add DT_SYMBOLIC for compatibility with older loaders.
4728 odyn
->add_constant(elfcpp::DT_SYMBOLIC
, 0);
4730 if (parameters
->options().now())
4731 flags
|= elfcpp::DF_BIND_NOW
;
4733 odyn
->add_constant(elfcpp::DT_FLAGS
, flags
);
4736 if (parameters
->options().initfirst())
4737 flags
|= elfcpp::DF_1_INITFIRST
;
4738 if (parameters
->options().interpose())
4739 flags
|= elfcpp::DF_1_INTERPOSE
;
4740 if (parameters
->options().loadfltr())
4741 flags
|= elfcpp::DF_1_LOADFLTR
;
4742 if (parameters
->options().nodefaultlib())
4743 flags
|= elfcpp::DF_1_NODEFLIB
;
4744 if (parameters
->options().nodelete())
4745 flags
|= elfcpp::DF_1_NODELETE
;
4746 if (parameters
->options().nodlopen())
4747 flags
|= elfcpp::DF_1_NOOPEN
;
4748 if (parameters
->options().nodump())
4749 flags
|= elfcpp::DF_1_NODUMP
;
4750 if (!parameters
->options().shared())
4751 flags
&= ~(elfcpp::DF_1_INITFIRST
4752 | elfcpp::DF_1_NODELETE
4753 | elfcpp::DF_1_NOOPEN
);
4754 if (parameters
->options().origin())
4755 flags
|= elfcpp::DF_1_ORIGIN
;
4756 if (parameters
->options().now())
4757 flags
|= elfcpp::DF_1_NOW
;
4758 if (parameters
->options().Bgroup())
4759 flags
|= elfcpp::DF_1_GROUP
;
4761 odyn
->add_constant(elfcpp::DT_FLAGS_1
, flags
);
4764 // Set the size of the _DYNAMIC symbol table to be the size of the
4768 Layout::set_dynamic_symbol_size(const Symbol_table
* symtab
)
4770 Output_data_dynamic
* const odyn
= this->dynamic_data_
;
4773 odyn
->finalize_data_size();
4774 if (this->dynamic_symbol_
== NULL
)
4776 off_t data_size
= odyn
->data_size();
4777 const int size
= parameters
->target().get_size();
4779 symtab
->get_sized_symbol
<32>(this->dynamic_symbol_
)->set_symsize(data_size
);
4780 else if (size
== 64)
4781 symtab
->get_sized_symbol
<64>(this->dynamic_symbol_
)->set_symsize(data_size
);
4786 // The mapping of input section name prefixes to output section names.
4787 // In some cases one prefix is itself a prefix of another prefix; in
4788 // such a case the longer prefix must come first. These prefixes are
4789 // based on the GNU linker default ELF linker script.
4791 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
4792 #define MAPPING_INIT_EXACT(f, t) { f, 0, t, sizeof(t) - 1 }
4793 const Layout::Section_name_mapping
Layout::section_name_mapping
[] =
4795 MAPPING_INIT(".text.", ".text"),
4796 MAPPING_INIT(".rodata.", ".rodata"),
4797 MAPPING_INIT(".data.rel.ro.local.", ".data.rel.ro.local"),
4798 MAPPING_INIT_EXACT(".data.rel.ro.local", ".data.rel.ro.local"),
4799 MAPPING_INIT(".data.rel.ro.", ".data.rel.ro"),
4800 MAPPING_INIT_EXACT(".data.rel.ro", ".data.rel.ro"),
4801 MAPPING_INIT(".data.", ".data"),
4802 MAPPING_INIT(".bss.", ".bss"),
4803 MAPPING_INIT(".tdata.", ".tdata"),
4804 MAPPING_INIT(".tbss.", ".tbss"),
4805 MAPPING_INIT(".init_array.", ".init_array"),
4806 MAPPING_INIT(".fini_array.", ".fini_array"),
4807 MAPPING_INIT(".sdata.", ".sdata"),
4808 MAPPING_INIT(".sbss.", ".sbss"),
4809 // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
4810 // differently depending on whether it is creating a shared library.
4811 MAPPING_INIT(".sdata2.", ".sdata"),
4812 MAPPING_INIT(".sbss2.", ".sbss"),
4813 MAPPING_INIT(".lrodata.", ".lrodata"),
4814 MAPPING_INIT(".ldata.", ".ldata"),
4815 MAPPING_INIT(".lbss.", ".lbss"),
4816 MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
4817 MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
4818 MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
4819 MAPPING_INIT(".gnu.linkonce.t.", ".text"),
4820 MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
4821 MAPPING_INIT(".gnu.linkonce.d.", ".data"),
4822 MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
4823 MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
4824 MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
4825 MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
4826 MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
4827 MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
4828 MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
4829 MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
4830 MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
4831 MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
4832 MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
4833 MAPPING_INIT(".ARM.extab", ".ARM.extab"),
4834 MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
4835 MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
4836 MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
4839 #undef MAPPING_INIT_EXACT
4841 const int Layout::section_name_mapping_count
=
4842 (sizeof(Layout::section_name_mapping
)
4843 / sizeof(Layout::section_name_mapping
[0]));
4845 // Choose the output section name to use given an input section name.
4846 // Set *PLEN to the length of the name. *PLEN is initialized to the
4850 Layout::output_section_name(const Relobj
* relobj
, const char* name
,
4853 // gcc 4.3 generates the following sorts of section names when it
4854 // needs a section name specific to a function:
4860 // .data.rel.local.FN
4862 // .data.rel.ro.local.FN
4869 // The GNU linker maps all of those to the part before the .FN,
4870 // except that .data.rel.local.FN is mapped to .data, and
4871 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
4872 // beginning with .data.rel.ro.local are grouped together.
4874 // For an anonymous namespace, the string FN can contain a '.'.
4876 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
4877 // GNU linker maps to .rodata.
4879 // The .data.rel.ro sections are used with -z relro. The sections
4880 // are recognized by name. We use the same names that the GNU
4881 // linker does for these sections.
4883 // It is hard to handle this in a principled way, so we don't even
4884 // try. We use a table of mappings. If the input section name is
4885 // not found in the table, we simply use it as the output section
4888 const Section_name_mapping
* psnm
= section_name_mapping
;
4889 for (int i
= 0; i
< section_name_mapping_count
; ++i
, ++psnm
)
4891 if (psnm
->fromlen
> 0)
4893 if (strncmp(name
, psnm
->from
, psnm
->fromlen
) == 0)
4895 *plen
= psnm
->tolen
;
4901 if (strcmp(name
, psnm
->from
) == 0)
4903 *plen
= psnm
->tolen
;
4909 // As an additional complication, .ctors sections are output in
4910 // either .ctors or .init_array sections, and .dtors sections are
4911 // output in either .dtors or .fini_array sections.
4912 if (is_prefix_of(".ctors.", name
) || is_prefix_of(".dtors.", name
))
4914 if (parameters
->options().ctors_in_init_array())
4917 return name
[1] == 'c' ? ".init_array" : ".fini_array";
4922 return name
[1] == 'c' ? ".ctors" : ".dtors";
4925 if (parameters
->options().ctors_in_init_array()
4926 && (strcmp(name
, ".ctors") == 0 || strcmp(name
, ".dtors") == 0))
4928 // To make .init_array/.fini_array work with gcc we must exclude
4929 // .ctors and .dtors sections from the crtbegin and crtend
4932 || (!Layout::match_file_name(relobj
, "crtbegin")
4933 && !Layout::match_file_name(relobj
, "crtend")))
4936 return name
[1] == 'c' ? ".init_array" : ".fini_array";
4943 // Return true if RELOBJ is an input file whose base name matches
4944 // FILE_NAME. The base name must have an extension of ".o", and must
4945 // be exactly FILE_NAME.o or FILE_NAME, one character, ".o". This is
4946 // to match crtbegin.o as well as crtbeginS.o without getting confused
4947 // by other possibilities. Overall matching the file name this way is
4948 // a dreadful hack, but the GNU linker does it in order to better
4949 // support gcc, and we need to be compatible.
4952 Layout::match_file_name(const Relobj
* relobj
, const char* match
)
4954 const std::string
& file_name(relobj
->name());
4955 const char* base_name
= lbasename(file_name
.c_str());
4956 size_t match_len
= strlen(match
);
4957 if (strncmp(base_name
, match
, match_len
) != 0)
4959 size_t base_len
= strlen(base_name
);
4960 if (base_len
!= match_len
+ 2 && base_len
!= match_len
+ 3)
4962 return memcmp(base_name
+ base_len
- 2, ".o", 2) == 0;
4965 // Check if a comdat group or .gnu.linkonce section with the given
4966 // NAME is selected for the link. If there is already a section,
4967 // *KEPT_SECTION is set to point to the existing section and the
4968 // function returns false. Otherwise, OBJECT, SHNDX, IS_COMDAT, and
4969 // IS_GROUP_NAME are recorded for this NAME in the layout object,
4970 // *KEPT_SECTION is set to the internal copy and the function returns
4974 Layout::find_or_add_kept_section(const std::string
& name
,
4979 Kept_section
** kept_section
)
4981 // It's normal to see a couple of entries here, for the x86 thunk
4982 // sections. If we see more than a few, we're linking a C++
4983 // program, and we resize to get more space to minimize rehashing.
4984 if (this->signatures_
.size() > 4
4985 && !this->resized_signatures_
)
4987 reserve_unordered_map(&this->signatures_
,
4988 this->number_of_input_files_
* 64);
4989 this->resized_signatures_
= true;
4992 Kept_section candidate
;
4993 std::pair
<Signatures::iterator
, bool> ins
=
4994 this->signatures_
.insert(std::make_pair(name
, candidate
));
4996 if (kept_section
!= NULL
)
4997 *kept_section
= &ins
.first
->second
;
5000 // This is the first time we've seen this signature.
5001 ins
.first
->second
.set_object(object
);
5002 ins
.first
->second
.set_shndx(shndx
);
5004 ins
.first
->second
.set_is_comdat();
5006 ins
.first
->second
.set_is_group_name();
5010 // We have already seen this signature.
5012 if (ins
.first
->second
.is_group_name())
5014 // We've already seen a real section group with this signature.
5015 // If the kept group is from a plugin object, and we're in the
5016 // replacement phase, accept the new one as a replacement.
5017 if (ins
.first
->second
.object() == NULL
5018 && parameters
->options().plugins()->in_replacement_phase())
5020 ins
.first
->second
.set_object(object
);
5021 ins
.first
->second
.set_shndx(shndx
);
5026 else if (is_group_name
)
5028 // This is a real section group, and we've already seen a
5029 // linkonce section with this signature. Record that we've seen
5030 // a section group, and don't include this section group.
5031 ins
.first
->second
.set_is_group_name();
5036 // We've already seen a linkonce section and this is a linkonce
5037 // section. These don't block each other--this may be the same
5038 // symbol name with different section types.
5043 // Store the allocated sections into the section list.
5046 Layout::get_allocated_sections(Section_list
* section_list
) const
5048 for (Section_list::const_iterator p
= this->section_list_
.begin();
5049 p
!= this->section_list_
.end();
5051 if (((*p
)->flags() & elfcpp::SHF_ALLOC
) != 0)
5052 section_list
->push_back(*p
);
5055 // Store the executable sections into the section list.
5058 Layout::get_executable_sections(Section_list
* section_list
) const
5060 for (Section_list::const_iterator p
= this->section_list_
.begin();
5061 p
!= this->section_list_
.end();
5063 if (((*p
)->flags() & (elfcpp::SHF_ALLOC
| elfcpp::SHF_EXECINSTR
))
5064 == (elfcpp::SHF_ALLOC
| elfcpp::SHF_EXECINSTR
))
5065 section_list
->push_back(*p
);
5068 // Create an output segment.
5071 Layout::make_output_segment(elfcpp::Elf_Word type
, elfcpp::Elf_Word flags
)
5073 gold_assert(!parameters
->options().relocatable());
5074 Output_segment
* oseg
= new Output_segment(type
, flags
);
5075 this->segment_list_
.push_back(oseg
);
5077 if (type
== elfcpp::PT_TLS
)
5078 this->tls_segment_
= oseg
;
5079 else if (type
== elfcpp::PT_GNU_RELRO
)
5080 this->relro_segment_
= oseg
;
5081 else if (type
== elfcpp::PT_INTERP
)
5082 this->interp_segment_
= oseg
;
5087 // Return the file offset of the normal symbol table.
5090 Layout::symtab_section_offset() const
5092 if (this->symtab_section_
!= NULL
)
5093 return this->symtab_section_
->offset();
5097 // Return the section index of the normal symbol table. It may have
5098 // been stripped by the -s/--strip-all option.
5101 Layout::symtab_section_shndx() const
5103 if (this->symtab_section_
!= NULL
)
5104 return this->symtab_section_
->out_shndx();
5108 // Write out the Output_sections. Most won't have anything to write,
5109 // since most of the data will come from input sections which are
5110 // handled elsewhere. But some Output_sections do have Output_data.
5113 Layout::write_output_sections(Output_file
* of
) const
5115 for (Section_list::const_iterator p
= this->section_list_
.begin();
5116 p
!= this->section_list_
.end();
5119 if (!(*p
)->after_input_sections())
5124 // Write out data not associated with a section or the symbol table.
5127 Layout::write_data(const Symbol_table
* symtab
, Output_file
* of
) const
5129 if (!parameters
->options().strip_all())
5131 const Output_section
* symtab_section
= this->symtab_section_
;
5132 for (Section_list::const_iterator p
= this->section_list_
.begin();
5133 p
!= this->section_list_
.end();
5136 if ((*p
)->needs_symtab_index())
5138 gold_assert(symtab_section
!= NULL
);
5139 unsigned int index
= (*p
)->symtab_index();
5140 gold_assert(index
> 0 && index
!= -1U);
5141 off_t off
= (symtab_section
->offset()
5142 + index
* symtab_section
->entsize());
5143 symtab
->write_section_symbol(*p
, this->symtab_xindex_
, of
, off
);
5148 const Output_section
* dynsym_section
= this->dynsym_section_
;
5149 for (Section_list::const_iterator p
= this->section_list_
.begin();
5150 p
!= this->section_list_
.end();
5153 if ((*p
)->needs_dynsym_index())
5155 gold_assert(dynsym_section
!= NULL
);
5156 unsigned int index
= (*p
)->dynsym_index();
5157 gold_assert(index
> 0 && index
!= -1U);
5158 off_t off
= (dynsym_section
->offset()
5159 + index
* dynsym_section
->entsize());
5160 symtab
->write_section_symbol(*p
, this->dynsym_xindex_
, of
, off
);
5164 // Write out the Output_data which are not in an Output_section.
5165 for (Data_list::const_iterator p
= this->special_output_list_
.begin();
5166 p
!= this->special_output_list_
.end();
5171 // Write out the Output_sections which can only be written after the
5172 // input sections are complete.
5175 Layout::write_sections_after_input_sections(Output_file
* of
)
5177 // Determine the final section offsets, and thus the final output
5178 // file size. Note we finalize the .shstrab last, to allow the
5179 // after_input_section sections to modify their section-names before
5181 if (this->any_postprocessing_sections_
)
5183 off_t off
= this->output_file_size_
;
5184 off
= this->set_section_offsets(off
, POSTPROCESSING_SECTIONS_PASS
);
5186 // Now that we've finalized the names, we can finalize the shstrab.
5188 this->set_section_offsets(off
,
5189 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
);
5191 if (off
> this->output_file_size_
)
5194 this->output_file_size_
= off
;
5198 for (Section_list::const_iterator p
= this->section_list_
.begin();
5199 p
!= this->section_list_
.end();
5202 if ((*p
)->after_input_sections())
5206 this->section_headers_
->write(of
);
5209 // If the build ID requires computing a checksum, do so here, and
5210 // write it out. We compute a checksum over the entire file because
5211 // that is simplest.
5214 Layout::write_build_id(Output_file
* of
) const
5216 if (this->build_id_note_
== NULL
)
5219 const unsigned char* iv
= of
->get_input_view(0, this->output_file_size_
);
5221 unsigned char* ov
= of
->get_output_view(this->build_id_note_
->offset(),
5222 this->build_id_note_
->data_size());
5224 const char* style
= parameters
->options().build_id();
5225 if (strcmp(style
, "sha1") == 0)
5228 sha1_init_ctx(&ctx
);
5229 sha1_process_bytes(iv
, this->output_file_size_
, &ctx
);
5230 sha1_finish_ctx(&ctx
, ov
);
5232 else if (strcmp(style
, "md5") == 0)
5236 md5_process_bytes(iv
, this->output_file_size_
, &ctx
);
5237 md5_finish_ctx(&ctx
, ov
);
5242 of
->write_output_view(this->build_id_note_
->offset(),
5243 this->build_id_note_
->data_size(),
5246 of
->free_input_view(0, this->output_file_size_
, iv
);
5249 // Write out a binary file. This is called after the link is
5250 // complete. IN is the temporary output file we used to generate the
5251 // ELF code. We simply walk through the segments, read them from
5252 // their file offset in IN, and write them to their load address in
5253 // the output file. FIXME: with a bit more work, we could support
5254 // S-records and/or Intel hex format here.
5257 Layout::write_binary(Output_file
* in
) const
5259 gold_assert(parameters
->options().oformat_enum()
5260 == General_options::OBJECT_FORMAT_BINARY
);
5262 // Get the size of the binary file.
5263 uint64_t max_load_address
= 0;
5264 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5265 p
!= this->segment_list_
.end();
5268 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
5270 uint64_t max_paddr
= (*p
)->paddr() + (*p
)->filesz();
5271 if (max_paddr
> max_load_address
)
5272 max_load_address
= max_paddr
;
5276 Output_file
out(parameters
->options().output_file_name());
5277 out
.open(max_load_address
);
5279 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5280 p
!= this->segment_list_
.end();
5283 if ((*p
)->type() == elfcpp::PT_LOAD
&& (*p
)->filesz() > 0)
5285 const unsigned char* vin
= in
->get_input_view((*p
)->offset(),
5287 unsigned char* vout
= out
.get_output_view((*p
)->paddr(),
5289 memcpy(vout
, vin
, (*p
)->filesz());
5290 out
.write_output_view((*p
)->paddr(), (*p
)->filesz(), vout
);
5291 in
->free_input_view((*p
)->offset(), (*p
)->filesz(), vin
);
5298 // Print the output sections to the map file.
5301 Layout::print_to_mapfile(Mapfile
* mapfile
) const
5303 for (Segment_list::const_iterator p
= this->segment_list_
.begin();
5304 p
!= this->segment_list_
.end();
5306 (*p
)->print_sections_to_mapfile(mapfile
);
5309 // Print statistical information to stderr. This is used for --stats.
5312 Layout::print_stats() const
5314 this->namepool_
.print_stats("section name pool");
5315 this->sympool_
.print_stats("output symbol name pool");
5316 this->dynpool_
.print_stats("dynamic name pool");
5318 for (Section_list::const_iterator p
= this->section_list_
.begin();
5319 p
!= this->section_list_
.end();
5321 (*p
)->print_merge_stats();
5324 // Write_sections_task methods.
5326 // We can always run this task.
5329 Write_sections_task::is_runnable()
5334 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
5338 Write_sections_task::locks(Task_locker
* tl
)
5340 tl
->add(this, this->output_sections_blocker_
);
5341 tl
->add(this, this->final_blocker_
);
5344 // Run the task--write out the data.
5347 Write_sections_task::run(Workqueue
*)
5349 this->layout_
->write_output_sections(this->of_
);
5352 // Write_data_task methods.
5354 // We can always run this task.
5357 Write_data_task::is_runnable()
5362 // We need to unlock FINAL_BLOCKER when finished.
5365 Write_data_task::locks(Task_locker
* tl
)
5367 tl
->add(this, this->final_blocker_
);
5370 // Run the task--write out the data.
5373 Write_data_task::run(Workqueue
*)
5375 this->layout_
->write_data(this->symtab_
, this->of_
);
5378 // Write_symbols_task methods.
5380 // We can always run this task.
5383 Write_symbols_task::is_runnable()
5388 // We need to unlock FINAL_BLOCKER when finished.
5391 Write_symbols_task::locks(Task_locker
* tl
)
5393 tl
->add(this, this->final_blocker_
);
5396 // Run the task--write out the symbols.
5399 Write_symbols_task::run(Workqueue
*)
5401 this->symtab_
->write_globals(this->sympool_
, this->dynpool_
,
5402 this->layout_
->symtab_xindex(),
5403 this->layout_
->dynsym_xindex(), this->of_
);
5406 // Write_after_input_sections_task methods.
5408 // We can only run this task after the input sections have completed.
5411 Write_after_input_sections_task::is_runnable()
5413 if (this->input_sections_blocker_
->is_blocked())
5414 return this->input_sections_blocker_
;
5418 // We need to unlock FINAL_BLOCKER when finished.
5421 Write_after_input_sections_task::locks(Task_locker
* tl
)
5423 tl
->add(this, this->final_blocker_
);
5429 Write_after_input_sections_task::run(Workqueue
*)
5431 this->layout_
->write_sections_after_input_sections(this->of_
);
5434 // Close_task_runner methods.
5436 // Run the task--close the file.
5439 Close_task_runner::run(Workqueue
*, const Task
*)
5441 // If we need to compute a checksum for the BUILD if, we do so here.
5442 this->layout_
->write_build_id(this->of_
);
5444 // If we've been asked to create a binary file, we do so here.
5445 if (this->options_
->oformat_enum() != General_options::OBJECT_FORMAT_ELF
)
5446 this->layout_
->write_binary(this->of_
);
5451 // Instantiate the templates we need. We could use the configure
5452 // script to restrict this to only the ones for implemented targets.
5454 #ifdef HAVE_TARGET_32_LITTLE
5457 Layout::init_fixed_output_section
<32, false>(
5459 elfcpp::Shdr
<32, false>& shdr
);
5462 #ifdef HAVE_TARGET_32_BIG
5465 Layout::init_fixed_output_section
<32, true>(
5467 elfcpp::Shdr
<32, true>& shdr
);
5470 #ifdef HAVE_TARGET_64_LITTLE
5473 Layout::init_fixed_output_section
<64, false>(
5475 elfcpp::Shdr
<64, false>& shdr
);
5478 #ifdef HAVE_TARGET_64_BIG
5481 Layout::init_fixed_output_section
<64, true>(
5483 elfcpp::Shdr
<64, true>& shdr
);
5486 #ifdef HAVE_TARGET_32_LITTLE
5489 Layout::layout
<32, false>(Sized_relobj_file
<32, false>* object
,
5492 const elfcpp::Shdr
<32, false>& shdr
,
5493 unsigned int, unsigned int, off_t
*);
5496 #ifdef HAVE_TARGET_32_BIG
5499 Layout::layout
<32, true>(Sized_relobj_file
<32, true>* object
,
5502 const elfcpp::Shdr
<32, true>& shdr
,
5503 unsigned int, unsigned int, off_t
*);
5506 #ifdef HAVE_TARGET_64_LITTLE
5509 Layout::layout
<64, false>(Sized_relobj_file
<64, false>* object
,
5512 const elfcpp::Shdr
<64, false>& shdr
,
5513 unsigned int, unsigned int, off_t
*);
5516 #ifdef HAVE_TARGET_64_BIG
5519 Layout::layout
<64, true>(Sized_relobj_file
<64, true>* object
,
5522 const elfcpp::Shdr
<64, true>& shdr
,
5523 unsigned int, unsigned int, off_t
*);
5526 #ifdef HAVE_TARGET_32_LITTLE
5529 Layout::layout_reloc
<32, false>(Sized_relobj_file
<32, false>* object
,
5530 unsigned int reloc_shndx
,
5531 const elfcpp::Shdr
<32, false>& shdr
,
5532 Output_section
* data_section
,
5533 Relocatable_relocs
* rr
);
5536 #ifdef HAVE_TARGET_32_BIG
5539 Layout::layout_reloc
<32, true>(Sized_relobj_file
<32, true>* object
,
5540 unsigned int reloc_shndx
,
5541 const elfcpp::Shdr
<32, true>& shdr
,
5542 Output_section
* data_section
,
5543 Relocatable_relocs
* rr
);
5546 #ifdef HAVE_TARGET_64_LITTLE
5549 Layout::layout_reloc
<64, false>(Sized_relobj_file
<64, false>* object
,
5550 unsigned int reloc_shndx
,
5551 const elfcpp::Shdr
<64, false>& shdr
,
5552 Output_section
* data_section
,
5553 Relocatable_relocs
* rr
);
5556 #ifdef HAVE_TARGET_64_BIG
5559 Layout::layout_reloc
<64, true>(Sized_relobj_file
<64, true>* object
,
5560 unsigned int reloc_shndx
,
5561 const elfcpp::Shdr
<64, true>& shdr
,
5562 Output_section
* data_section
,
5563 Relocatable_relocs
* rr
);
5566 #ifdef HAVE_TARGET_32_LITTLE
5569 Layout::layout_group
<32, false>(Symbol_table
* symtab
,
5570 Sized_relobj_file
<32, false>* object
,
5572 const char* group_section_name
,
5573 const char* signature
,
5574 const elfcpp::Shdr
<32, false>& shdr
,
5575 elfcpp::Elf_Word flags
,
5576 std::vector
<unsigned int>* shndxes
);
5579 #ifdef HAVE_TARGET_32_BIG
5582 Layout::layout_group
<32, true>(Symbol_table
* symtab
,
5583 Sized_relobj_file
<32, true>* object
,
5585 const char* group_section_name
,
5586 const char* signature
,
5587 const elfcpp::Shdr
<32, true>& shdr
,
5588 elfcpp::Elf_Word flags
,
5589 std::vector
<unsigned int>* shndxes
);
5592 #ifdef HAVE_TARGET_64_LITTLE
5595 Layout::layout_group
<64, false>(Symbol_table
* symtab
,
5596 Sized_relobj_file
<64, false>* object
,
5598 const char* group_section_name
,
5599 const char* signature
,
5600 const elfcpp::Shdr
<64, false>& shdr
,
5601 elfcpp::Elf_Word flags
,
5602 std::vector
<unsigned int>* shndxes
);
5605 #ifdef HAVE_TARGET_64_BIG
5608 Layout::layout_group
<64, true>(Symbol_table
* symtab
,
5609 Sized_relobj_file
<64, true>* object
,
5611 const char* group_section_name
,
5612 const char* signature
,
5613 const elfcpp::Shdr
<64, true>& shdr
,
5614 elfcpp::Elf_Word flags
,
5615 std::vector
<unsigned int>* shndxes
);
5618 #ifdef HAVE_TARGET_32_LITTLE
5621 Layout::layout_eh_frame
<32, false>(Sized_relobj_file
<32, false>* object
,
5622 const unsigned char* symbols
,
5624 const unsigned char* symbol_names
,
5625 off_t symbol_names_size
,
5627 const elfcpp::Shdr
<32, false>& shdr
,
5628 unsigned int reloc_shndx
,
5629 unsigned int reloc_type
,
5633 #ifdef HAVE_TARGET_32_BIG
5636 Layout::layout_eh_frame
<32, true>(Sized_relobj_file
<32, true>* object
,
5637 const unsigned char* symbols
,
5639 const unsigned char* symbol_names
,
5640 off_t symbol_names_size
,
5642 const elfcpp::Shdr
<32, true>& shdr
,
5643 unsigned int reloc_shndx
,
5644 unsigned int reloc_type
,
5648 #ifdef HAVE_TARGET_64_LITTLE
5651 Layout::layout_eh_frame
<64, false>(Sized_relobj_file
<64, false>* object
,
5652 const unsigned char* symbols
,
5654 const unsigned char* symbol_names
,
5655 off_t symbol_names_size
,
5657 const elfcpp::Shdr
<64, false>& shdr
,
5658 unsigned int reloc_shndx
,
5659 unsigned int reloc_type
,
5663 #ifdef HAVE_TARGET_64_BIG
5666 Layout::layout_eh_frame
<64, true>(Sized_relobj_file
<64, true>* object
,
5667 const unsigned char* symbols
,
5669 const unsigned char* symbol_names
,
5670 off_t symbol_names_size
,
5672 const elfcpp::Shdr
<64, true>& shdr
,
5673 unsigned int reloc_shndx
,
5674 unsigned int reloc_type
,
5678 #ifdef HAVE_TARGET_32_LITTLE
5681 Layout::add_to_gdb_index(bool is_type_unit
,
5682 Sized_relobj
<32, false>* object
,
5683 const unsigned char* symbols
,
5686 unsigned int reloc_shndx
,
5687 unsigned int reloc_type
);
5690 #ifdef HAVE_TARGET_32_BIG
5693 Layout::add_to_gdb_index(bool is_type_unit
,
5694 Sized_relobj
<32, true>* object
,
5695 const unsigned char* symbols
,
5698 unsigned int reloc_shndx
,
5699 unsigned int reloc_type
);
5702 #ifdef HAVE_TARGET_64_LITTLE
5705 Layout::add_to_gdb_index(bool is_type_unit
,
5706 Sized_relobj
<64, false>* object
,
5707 const unsigned char* symbols
,
5710 unsigned int reloc_shndx
,
5711 unsigned int reloc_type
);
5714 #ifdef HAVE_TARGET_64_BIG
5717 Layout::add_to_gdb_index(bool is_type_unit
,
5718 Sized_relobj
<64, true>* object
,
5719 const unsigned char* symbols
,
5722 unsigned int reloc_shndx
,
5723 unsigned int reloc_type
);
5726 } // End namespace gold.