1 // script-sections.cc -- linker script SECTIONS for gold
3 // Copyright 2008, 2009 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
33 #include "parameters.h"
39 #include "script-sections.h"
41 // Support for the SECTIONS clause in linker scripts.
46 // Manage orphan sections. This is intended to be largely compatible
47 // with the GNU linker. The Linux kernel implicitly relies on
48 // something similar to the GNU linker's orphan placement. We
49 // originally used a simpler scheme here, but it caused the kernel
50 // build to fail, and was also rather inefficient.
52 class Orphan_section_placement
55 typedef Script_sections::Elements_iterator Elements_iterator;
58 Orphan_section_placement();
60 // Handle an output section during initialization of this mapping.
62 output_section_init(const std::string& name, Output_section*,
63 Elements_iterator location);
65 // Initialize the last location.
67 last_init(Elements_iterator location);
69 // Set *PWHERE to the address of an iterator pointing to the
70 // location to use for an orphan section. Return true if the
71 // iterator has a value, false otherwise.
73 find_place(Output_section*, Elements_iterator** pwhere);
75 // Return the iterator being used for sections at the very end of
81 // The places that we specifically recognize. This list is copied
82 // from the GNU linker.
98 // The information we keep for a specific place.
101 // The name of sections for this place.
103 // Whether we have a location for this place.
105 // The iterator for this place.
106 Elements_iterator location;
109 // Initialize one place element.
111 initialize_place(Place_index, const char*);
114 Place places_[PLACE_MAX];
115 // True if this is the first call to output_section_init.
119 // Initialize Orphan_section_placement.
121 Orphan_section_placement::Orphan_section_placement()
124 this->initialize_place(PLACE_TEXT, ".text");
125 this->initialize_place(PLACE_RODATA, ".rodata");
126 this->initialize_place(PLACE_DATA, ".data");
127 this->initialize_place(PLACE_TLS, NULL);
128 this->initialize_place(PLACE_TLS_BSS, NULL);
129 this->initialize_place(PLACE_BSS, ".bss");
130 this->initialize_place(PLACE_REL, NULL);
131 this->initialize_place(PLACE_INTERP, ".interp");
132 this->initialize_place(PLACE_NONALLOC, NULL);
133 this->initialize_place(PLACE_LAST, NULL);
136 // Initialize one place element.
139 Orphan_section_placement::initialize_place(Place_index index, const char* name)
141 this->places_[index].name = name;
142 this->places_[index].have_location = false;
145 // While initializing the Orphan_section_placement information, this
146 // is called once for each output section named in the linker script.
147 // If we found an output section during the link, it will be passed in
151 Orphan_section_placement::output_section_init(const std::string& name,
153 Elements_iterator location)
155 bool first_init = this->first_init_;
156 this->first_init_ = false;
158 for (int i = 0; i < PLACE_MAX; ++i)
160 if (this->places_[i].name != NULL && this->places_[i].name == name)
162 if (this->places_[i].have_location)
164 // We have already seen a section with this name.
168 this->places_[i].location = location;
169 this->places_[i].have_location = true;
171 // If we just found the .bss section, restart the search for
172 // an unallocated section. This follows the GNU linker's
175 this->places_[PLACE_NONALLOC].have_location = false;
181 // Relocation sections.
182 if (!this->places_[PLACE_REL].have_location
184 && (os->type() == elfcpp::SHT_REL || os->type() == elfcpp::SHT_RELA)
185 && (os->flags() & elfcpp::SHF_ALLOC) != 0)
187 this->places_[PLACE_REL].location = location;
188 this->places_[PLACE_REL].have_location = true;
191 // We find the location for unallocated sections by finding the
192 // first debugging or comment section after the BSS section (if
194 if (!this->places_[PLACE_NONALLOC].have_location
195 && (name == ".comment" || Layout::is_debug_info_section(name.c_str())))
197 // We add orphan sections after the location in PLACES_. We
198 // want to store unallocated sections before LOCATION. If this
199 // is the very first section, we can't use it.
203 this->places_[PLACE_NONALLOC].location = location;
204 this->places_[PLACE_NONALLOC].have_location = true;
209 // Initialize the last location.
212 Orphan_section_placement::last_init(Elements_iterator location)
214 this->places_[PLACE_LAST].location = location;
215 this->places_[PLACE_LAST].have_location = true;
218 // Set *PWHERE to the address of an iterator pointing to the location
219 // to use for an orphan section. Return true if the iterator has a
220 // value, false otherwise.
223 Orphan_section_placement::find_place(Output_section* os,
224 Elements_iterator** pwhere)
226 // Figure out where OS should go. This is based on the GNU linker
227 // code. FIXME: The GNU linker handles small data sections
228 // specially, but we don't.
229 elfcpp::Elf_Word type = os->type();
230 elfcpp::Elf_Xword flags = os->flags();
232 if ((flags & elfcpp::SHF_ALLOC) == 0
233 && !Layout::is_debug_info_section(os->name()))
234 index = PLACE_NONALLOC;
235 else if ((flags & elfcpp::SHF_ALLOC) == 0)
237 else if (type == elfcpp::SHT_NOTE)
238 index = PLACE_INTERP;
239 else if ((flags & elfcpp::SHF_TLS) != 0)
241 if (type == elfcpp::SHT_NOBITS)
242 index = PLACE_TLS_BSS;
246 else if (type == elfcpp::SHT_NOBITS)
248 else if ((flags & elfcpp::SHF_WRITE) != 0)
250 else if (type == elfcpp::SHT_REL || type == elfcpp::SHT_RELA)
252 else if ((flags & elfcpp::SHF_EXECINSTR) == 0)
253 index = PLACE_RODATA;
257 // If we don't have a location yet, try to find one based on a
258 // plausible ordering of sections.
259 if (!this->places_[index].have_location)
284 if (!this->places_[PLACE_TLS].have_location)
288 if (follow != PLACE_MAX && this->places_[follow].have_location)
290 // Set the location of INDEX to the location of FOLLOW. The
291 // location of INDEX will then be incremented by the caller,
292 // so anything in INDEX will continue to be after anything
294 this->places_[index].location = this->places_[follow].location;
295 this->places_[index].have_location = true;
299 *pwhere = &this->places_[index].location;
300 bool ret = this->places_[index].have_location;
302 // The caller will set the location.
303 this->places_[index].have_location = true;
308 // Return the iterator being used for sections at the very end of the
311 Orphan_section_placement::Elements_iterator
312 Orphan_section_placement::last_place() const
314 gold_assert(this->places_[PLACE_LAST].have_location);
315 return this->places_[PLACE_LAST].location;
318 // An element in a SECTIONS clause.
320 class Sections_element
326 virtual ~Sections_element()
329 // Return whether an output section is relro.
334 // Record that an output section is relro.
339 // Create any required output sections. The only real
340 // implementation is in Output_section_definition.
342 create_sections(Layout*)
345 // Add any symbol being defined to the symbol table.
347 add_symbols_to_table(Symbol_table*)
350 // Finalize symbols and check assertions.
352 finalize_symbols(Symbol_table*, const Layout*, uint64_t*)
355 // Return the output section name to use for an input file name and
356 // section name. This only real implementation is in
357 // Output_section_definition.
359 output_section_name(const char*, const char*, Output_section***,
360 Script_sections::Section_type*)
363 // Initialize OSP with an output section.
365 orphan_section_init(Orphan_section_placement*,
366 Script_sections::Elements_iterator)
369 // Set section addresses. This includes applying assignments if the
370 // the expression is an absolute value.
372 set_section_addresses(Symbol_table*, Layout*, uint64_t*, uint64_t*,
376 // Check a constraint (ONLY_IF_RO, etc.) on an output section. If
377 // this section is constrained, and the input sections do not match,
378 // return the constraint, and set *POSD.
379 virtual Section_constraint
380 check_constraint(Output_section_definition**)
381 { return CONSTRAINT_NONE; }
383 // See if this is the alternate output section for a constrained
384 // output section. If it is, transfer the Output_section and return
385 // true. Otherwise return false.
387 alternate_constraint(Output_section_definition*, Section_constraint)
390 // Get the list of segments to use for an allocated section when
391 // using a PHDRS clause. If this is an allocated section, return
392 // the Output_section, and set *PHDRS_LIST (the first parameter) to
393 // the list of PHDRS to which it should be attached. If the PHDRS
394 // were not specified, don't change *PHDRS_LIST. When not returning
395 // NULL, set *ORPHAN (the second parameter) according to whether
396 // this is an orphan section--one that is not mentioned in the
398 virtual Output_section*
399 allocate_to_segment(String_list**, bool*)
402 // Look for an output section by name and return the address, the
403 // load address, the alignment, and the size. This is used when an
404 // expression refers to an output section which was not actually
405 // created. This returns true if the section was found, false
406 // otherwise. The only real definition is for
407 // Output_section_definition.
409 get_output_section_info(const char*, uint64_t*, uint64_t*, uint64_t*,
413 // Return the associated Output_section if there is one.
414 virtual Output_section*
415 get_output_section() const
418 // Print the element for debugging purposes.
420 print(FILE* f) const = 0;
423 // An assignment in a SECTIONS clause outside of an output section.
425 class Sections_element_assignment : public Sections_element
428 Sections_element_assignment(const char* name, size_t namelen,
429 Expression* val, bool provide, bool hidden)
430 : assignment_(name, namelen, false, val, provide, hidden)
433 // Add the symbol to the symbol table.
435 add_symbols_to_table(Symbol_table* symtab)
436 { this->assignment_.add_to_table(symtab); }
438 // Finalize the symbol.
440 finalize_symbols(Symbol_table* symtab, const Layout* layout,
443 this->assignment_.finalize_with_dot(symtab, layout, *dot_value, NULL);
446 // Set the section address. There is no section here, but if the
447 // value is absolute, we set the symbol. This permits us to use
448 // absolute symbols when setting dot.
450 set_section_addresses(Symbol_table* symtab, Layout* layout,
451 uint64_t* dot_value, uint64_t*, uint64_t*)
453 this->assignment_.set_if_absolute(symtab, layout, true, *dot_value);
456 // Print for debugging.
461 this->assignment_.print(f);
465 Symbol_assignment assignment_;
468 // An assignment to the dot symbol in a SECTIONS clause outside of an
471 class Sections_element_dot_assignment : public Sections_element
474 Sections_element_dot_assignment(Expression* val)
478 // Finalize the symbol.
480 finalize_symbols(Symbol_table* symtab, const Layout* layout,
483 // We ignore the section of the result because outside of an
484 // output section definition the dot symbol is always considered
486 Output_section* dummy;
487 *dot_value = this->val_->eval_with_dot(symtab, layout, true, *dot_value,
491 // Update the dot symbol while setting section addresses.
493 set_section_addresses(Symbol_table* symtab, Layout* layout,
494 uint64_t* dot_value, uint64_t* dot_alignment,
495 uint64_t* load_address)
497 Output_section* dummy;
498 *dot_value = this->val_->eval_with_dot(symtab, layout, false, *dot_value,
499 NULL, &dummy, dot_alignment);
500 *load_address = *dot_value;
503 // Print for debugging.
508 this->val_->print(f);
516 // An assertion in a SECTIONS clause outside of an output section.
518 class Sections_element_assertion : public Sections_element
521 Sections_element_assertion(Expression* check, const char* message,
523 : assertion_(check, message, messagelen)
526 // Check the assertion.
528 finalize_symbols(Symbol_table* symtab, const Layout* layout, uint64_t*)
529 { this->assertion_.check(symtab, layout); }
531 // Print for debugging.
536 this->assertion_.print(f);
540 Script_assertion assertion_;
543 // An element in an output section in a SECTIONS clause.
545 class Output_section_element
548 // A list of input sections.
549 typedef std::list<Output_section::Input_section> Input_section_list;
551 Output_section_element()
554 virtual ~Output_section_element()
557 // Return whether this element requires an output section to exist.
559 needs_output_section() const
562 // Add any symbol being defined to the symbol table.
564 add_symbols_to_table(Symbol_table*)
567 // Finalize symbols and check assertions.
569 finalize_symbols(Symbol_table*, const Layout*, uint64_t*, Output_section**)
572 // Return whether this element matches FILE_NAME and SECTION_NAME.
573 // The only real implementation is in Output_section_element_input.
575 match_name(const char*, const char*) const
578 // Set section addresses. This includes applying assignments if the
579 // the expression is an absolute value.
581 set_section_addresses(Symbol_table*, Layout*, Output_section*, uint64_t,
582 uint64_t*, uint64_t*, Output_section**, std::string*,
586 // Print the element for debugging purposes.
588 print(FILE* f) const = 0;
591 // Return a fill string that is LENGTH bytes long, filling it with
594 get_fill_string(const std::string* fill, section_size_type length) const;
598 Output_section_element::get_fill_string(const std::string* fill,
599 section_size_type length) const
601 std::string this_fill;
602 this_fill.reserve(length);
603 while (this_fill.length() + fill->length() <= length)
605 if (this_fill.length() < length)
606 this_fill.append(*fill, 0, length - this_fill.length());
610 // A symbol assignment in an output section.
612 class Output_section_element_assignment : public Output_section_element
615 Output_section_element_assignment(const char* name, size_t namelen,
616 Expression* val, bool provide,
618 : assignment_(name, namelen, false, val, provide, hidden)
621 // Add the symbol to the symbol table.
623 add_symbols_to_table(Symbol_table* symtab)
624 { this->assignment_.add_to_table(symtab); }
626 // Finalize the symbol.
628 finalize_symbols(Symbol_table* symtab, const Layout* layout,
629 uint64_t* dot_value, Output_section** dot_section)
631 this->assignment_.finalize_with_dot(symtab, layout, *dot_value,
635 // Set the section address. There is no section here, but if the
636 // value is absolute, we set the symbol. This permits us to use
637 // absolute symbols when setting dot.
639 set_section_addresses(Symbol_table* symtab, Layout* layout, Output_section*,
640 uint64_t, uint64_t* dot_value, uint64_t*,
641 Output_section**, std::string*, Input_section_list*)
643 this->assignment_.set_if_absolute(symtab, layout, true, *dot_value);
646 // Print for debugging.
651 this->assignment_.print(f);
655 Symbol_assignment assignment_;
658 // An assignment to the dot symbol in an output section.
660 class Output_section_element_dot_assignment : public Output_section_element
663 Output_section_element_dot_assignment(Expression* val)
667 // Finalize the symbol.
669 finalize_symbols(Symbol_table* symtab, const Layout* layout,
670 uint64_t* dot_value, Output_section** dot_section)
672 *dot_value = this->val_->eval_with_dot(symtab, layout, true, *dot_value,
673 *dot_section, dot_section, NULL);
676 // Update the dot symbol while setting section addresses.
678 set_section_addresses(Symbol_table* symtab, Layout* layout, Output_section*,
679 uint64_t, uint64_t* dot_value, uint64_t*,
680 Output_section**, std::string*, Input_section_list*);
682 // Print for debugging.
687 this->val_->print(f);
695 // Update the dot symbol while setting section addresses.
698 Output_section_element_dot_assignment::set_section_addresses(
699 Symbol_table* symtab,
701 Output_section* output_section,
704 uint64_t* dot_alignment,
705 Output_section** dot_section,
709 uint64_t next_dot = this->val_->eval_with_dot(symtab, layout, false,
710 *dot_value, *dot_section,
711 dot_section, dot_alignment);
712 if (next_dot < *dot_value)
713 gold_error(_("dot may not move backward"));
714 if (next_dot > *dot_value && output_section != NULL)
716 section_size_type length = convert_to_section_size_type(next_dot
718 Output_section_data* posd;
720 posd = new Output_data_zero_fill(length, 0);
723 std::string this_fill = this->get_fill_string(fill, length);
724 posd = new Output_data_const(this_fill, 0);
726 output_section->add_output_section_data(posd);
727 layout->new_output_section_data_from_script(posd);
729 *dot_value = next_dot;
732 // An assertion in an output section.
734 class Output_section_element_assertion : public Output_section_element
737 Output_section_element_assertion(Expression* check, const char* message,
739 : assertion_(check, message, messagelen)
746 this->assertion_.print(f);
750 Script_assertion assertion_;
753 // We use a special instance of Output_section_data to handle BYTE,
754 // SHORT, etc. This permits forward references to symbols in the
757 class Output_data_expression : public Output_section_data
760 Output_data_expression(int size, bool is_signed, Expression* val,
761 const Symbol_table* symtab, const Layout* layout,
762 uint64_t dot_value, Output_section* dot_section)
763 : Output_section_data(size, 0, true),
764 is_signed_(is_signed), val_(val), symtab_(symtab),
765 layout_(layout), dot_value_(dot_value), dot_section_(dot_section)
769 // Write the data to the output file.
771 do_write(Output_file*);
773 // Write the data to a buffer.
775 do_write_to_buffer(unsigned char*);
777 // Write to a map file.
779 do_print_to_mapfile(Mapfile* mapfile) const
780 { mapfile->print_output_data(this, _("** expression")); }
783 template<bool big_endian>
785 endian_write_to_buffer(uint64_t, unsigned char*);
789 const Symbol_table* symtab_;
790 const Layout* layout_;
792 Output_section* dot_section_;
795 // Write the data element to the output file.
798 Output_data_expression::do_write(Output_file* of)
800 unsigned char* view = of->get_output_view(this->offset(), this->data_size());
801 this->write_to_buffer(view);
802 of->write_output_view(this->offset(), this->data_size(), view);
805 // Write the data element to a buffer.
808 Output_data_expression::do_write_to_buffer(unsigned char* buf)
810 Output_section* dummy;
811 uint64_t val = this->val_->eval_with_dot(this->symtab_, this->layout_,
812 true, this->dot_value_,
813 this->dot_section_, &dummy, NULL);
815 if (parameters->target().is_big_endian())
816 this->endian_write_to_buffer<true>(val, buf);
818 this->endian_write_to_buffer<false>(val, buf);
821 template<bool big_endian>
823 Output_data_expression::endian_write_to_buffer(uint64_t val,
826 switch (this->data_size())
829 elfcpp::Swap_unaligned<8, big_endian>::writeval(buf, val);
832 elfcpp::Swap_unaligned<16, big_endian>::writeval(buf, val);
835 elfcpp::Swap_unaligned<32, big_endian>::writeval(buf, val);
838 if (parameters->target().get_size() == 32)
841 if (this->is_signed_ && (val & 0x80000000) != 0)
842 val |= 0xffffffff00000000LL;
844 elfcpp::Swap_unaligned<64, big_endian>::writeval(buf, val);
851 // A data item in an output section.
853 class Output_section_element_data : public Output_section_element
856 Output_section_element_data(int size, bool is_signed, Expression* val)
857 : size_(size), is_signed_(is_signed), val_(val)
860 // If there is a data item, then we must create an output section.
862 needs_output_section() const
865 // Finalize symbols--we just need to update dot.
867 finalize_symbols(Symbol_table*, const Layout*, uint64_t* dot_value,
869 { *dot_value += this->size_; }
871 // Store the value in the section.
873 set_section_addresses(Symbol_table*, Layout*, Output_section*, uint64_t,
874 uint64_t* dot_value, uint64_t*, Output_section**,
875 std::string*, Input_section_list*);
877 // Print for debugging.
882 // The size in bytes.
884 // Whether the value is signed.
890 // Store the value in the section.
893 Output_section_element_data::set_section_addresses(
894 Symbol_table* symtab,
900 Output_section** dot_section,
904 gold_assert(os != NULL);
905 Output_data_expression* expression =
906 new Output_data_expression(this->size_, this->is_signed_, this->val_,
907 symtab, layout, *dot_value, *dot_section);
908 os->add_output_section_data(expression);
909 layout->new_output_section_data_from_script(expression);
910 *dot_value += this->size_;
913 // Print for debugging.
916 Output_section_element_data::print(FILE* f) const
931 if (this->is_signed_)
939 fprintf(f, " %s(", s);
940 this->val_->print(f);
944 // A fill value setting in an output section.
946 class Output_section_element_fill : public Output_section_element
949 Output_section_element_fill(Expression* val)
953 // Update the fill value while setting section addresses.
955 set_section_addresses(Symbol_table* symtab, Layout* layout, Output_section*,
956 uint64_t, uint64_t* dot_value, uint64_t*,
957 Output_section** dot_section,
958 std::string* fill, Input_section_list*)
960 Output_section* fill_section;
961 uint64_t fill_val = this->val_->eval_with_dot(symtab, layout, false,
962 *dot_value, *dot_section,
963 &fill_section, NULL);
964 if (fill_section != NULL)
965 gold_warning(_("fill value is not absolute"));
966 // FIXME: The GNU linker supports fill values of arbitrary length.
967 unsigned char fill_buff[4];
968 elfcpp::Swap_unaligned<32, true>::writeval(fill_buff, fill_val);
969 fill->assign(reinterpret_cast<char*>(fill_buff), 4);
972 // Print for debugging.
976 fprintf(f, " FILL(");
977 this->val_->print(f);
982 // The new fill value.
986 // Return whether STRING contains a wildcard character. This is used
987 // to speed up matching.
990 is_wildcard_string(const std::string& s)
992 return strpbrk(s.c_str(), "?*[") != NULL;
995 // An input section specification in an output section
997 class Output_section_element_input : public Output_section_element
1000 Output_section_element_input(const Input_section_spec* spec, bool keep);
1002 // Finalize symbols--just update the value of the dot symbol.
1004 finalize_symbols(Symbol_table*, const Layout*, uint64_t* dot_value,
1005 Output_section** dot_section)
1007 *dot_value = this->final_dot_value_;
1008 *dot_section = this->final_dot_section_;
1011 // See whether we match FILE_NAME and SECTION_NAME as an input
1014 match_name(const char* file_name, const char* section_name) const;
1016 // Set the section address.
1018 set_section_addresses(Symbol_table* symtab, Layout* layout, Output_section*,
1019 uint64_t subalign, uint64_t* dot_value, uint64_t*,
1020 Output_section**, std::string* fill,
1021 Input_section_list*);
1023 // Print for debugging.
1025 print(FILE* f) const;
1028 // An input section pattern.
1029 struct Input_section_pattern
1031 std::string pattern;
1032 bool pattern_is_wildcard;
1035 Input_section_pattern(const char* patterna, size_t patternlena,
1036 Sort_wildcard sorta)
1037 : pattern(patterna, patternlena),
1038 pattern_is_wildcard(is_wildcard_string(this->pattern)),
1043 typedef std::vector<Input_section_pattern> Input_section_patterns;
1045 // Filename_exclusions is a pair of filename pattern and a bool
1046 // indicating whether the filename is a wildcard.
1047 typedef std::vector<std::pair<std::string, bool> > Filename_exclusions;
1049 // Return whether STRING matches PATTERN, where IS_WILDCARD_PATTERN
1050 // indicates whether this is a wildcard pattern.
1052 match(const char* string, const char* pattern, bool is_wildcard_pattern)
1054 return (is_wildcard_pattern
1055 ? fnmatch(pattern, string, 0) == 0
1056 : strcmp(string, pattern) == 0);
1059 // See if we match a file name.
1061 match_file_name(const char* file_name) const;
1063 // The file name pattern. If this is the empty string, we match all
1065 std::string filename_pattern_;
1066 // Whether the file name pattern is a wildcard.
1067 bool filename_is_wildcard_;
1068 // How the file names should be sorted. This may only be
1069 // SORT_WILDCARD_NONE or SORT_WILDCARD_BY_NAME.
1070 Sort_wildcard filename_sort_;
1071 // The list of file names to exclude.
1072 Filename_exclusions filename_exclusions_;
1073 // The list of input section patterns.
1074 Input_section_patterns input_section_patterns_;
1075 // Whether to keep this section when garbage collecting.
1077 // The value of dot after including all matching sections.
1078 uint64_t final_dot_value_;
1079 // The section where dot is defined after including all matching
1081 Output_section* final_dot_section_;
1084 // Construct Output_section_element_input. The parser records strings
1085 // as pointers into a copy of the script file, which will go away when
1086 // parsing is complete. We make sure they are in std::string objects.
1088 Output_section_element_input::Output_section_element_input(
1089 const Input_section_spec* spec,
1091 : filename_pattern_(),
1092 filename_is_wildcard_(false),
1093 filename_sort_(spec->file.sort),
1094 filename_exclusions_(),
1095 input_section_patterns_(),
1097 final_dot_value_(0),
1098 final_dot_section_(NULL)
1100 // The filename pattern "*" is common, and matches all files. Turn
1101 // it into the empty string.
1102 if (spec->file.name.length != 1 || spec->file.name.value[0] != '*')
1103 this->filename_pattern_.assign(spec->file.name.value,
1104 spec->file.name.length);
1105 this->filename_is_wildcard_ = is_wildcard_string(this->filename_pattern_);
1107 if (spec->input_sections.exclude != NULL)
1109 for (String_list::const_iterator p =
1110 spec->input_sections.exclude->begin();
1111 p != spec->input_sections.exclude->end();
1114 bool is_wildcard = is_wildcard_string(*p);
1115 this->filename_exclusions_.push_back(std::make_pair(*p,
1120 if (spec->input_sections.sections != NULL)
1122 Input_section_patterns& isp(this->input_section_patterns_);
1123 for (String_sort_list::const_iterator p =
1124 spec->input_sections.sections->begin();
1125 p != spec->input_sections.sections->end();
1127 isp.push_back(Input_section_pattern(p->name.value, p->name.length,
1132 // See whether we match FILE_NAME.
1135 Output_section_element_input::match_file_name(const char* file_name) const
1137 if (!this->filename_pattern_.empty())
1139 // If we were called with no filename, we refuse to match a
1140 // pattern which requires a file name.
1141 if (file_name == NULL)
1144 if (!match(file_name, this->filename_pattern_.c_str(),
1145 this->filename_is_wildcard_))
1149 if (file_name != NULL)
1151 // Now we have to see whether FILE_NAME matches one of the
1152 // exclusion patterns, if any.
1153 for (Filename_exclusions::const_iterator p =
1154 this->filename_exclusions_.begin();
1155 p != this->filename_exclusions_.end();
1158 if (match(file_name, p->first.c_str(), p->second))
1166 // See whether we match FILE_NAME and SECTION_NAME.
1169 Output_section_element_input::match_name(const char* file_name,
1170 const char* section_name) const
1172 if (!this->match_file_name(file_name))
1175 // If there are no section name patterns, then we match.
1176 if (this->input_section_patterns_.empty())
1179 // See whether we match the section name patterns.
1180 for (Input_section_patterns::const_iterator p =
1181 this->input_section_patterns_.begin();
1182 p != this->input_section_patterns_.end();
1185 if (match(section_name, p->pattern.c_str(), p->pattern_is_wildcard))
1189 // We didn't match any section names, so we didn't match.
1193 // Information we use to sort the input sections.
1195 class Input_section_info
1198 Input_section_info(const Output_section::Input_section& input_section)
1199 : input_section_(input_section), section_name_(),
1200 size_(0), addralign_(1)
1203 // Return the simple input section.
1204 const Output_section::Input_section&
1205 input_section() const
1206 { return this->input_section_; }
1208 // Return the object.
1211 { return this->input_section_.relobj(); }
1213 // Return the section index.
1216 { return this->input_section_.shndx(); }
1218 // Return the section name.
1220 section_name() const
1221 { return this->section_name_; }
1223 // Set the section name.
1225 set_section_name(const std::string name)
1226 { this->section_name_ = name; }
1228 // Return the section size.
1231 { return this->size_; }
1233 // Set the section size.
1235 set_size(uint64_t size)
1236 { this->size_ = size; }
1238 // Return the address alignment.
1241 { return this->addralign_; }
1243 // Set the address alignment.
1245 set_addralign(uint64_t addralign)
1246 { this->addralign_ = addralign; }
1249 // Input section, can be a relaxed section.
1250 Output_section::Input_section input_section_;
1251 // Name of the section.
1252 std::string section_name_;
1255 // Address alignment.
1256 uint64_t addralign_;
1259 // A class to sort the input sections.
1261 class Input_section_sorter
1264 Input_section_sorter(Sort_wildcard filename_sort, Sort_wildcard section_sort)
1265 : filename_sort_(filename_sort), section_sort_(section_sort)
1269 operator()(const Input_section_info&, const Input_section_info&) const;
1272 Sort_wildcard filename_sort_;
1273 Sort_wildcard section_sort_;
1277 Input_section_sorter::operator()(const Input_section_info& isi1,
1278 const Input_section_info& isi2) const
1280 if (this->section_sort_ == SORT_WILDCARD_BY_NAME
1281 || this->section_sort_ == SORT_WILDCARD_BY_NAME_BY_ALIGNMENT
1282 || (this->section_sort_ == SORT_WILDCARD_BY_ALIGNMENT_BY_NAME
1283 && isi1.addralign() == isi2.addralign()))
1285 if (isi1.section_name() != isi2.section_name())
1286 return isi1.section_name() < isi2.section_name();
1288 if (this->section_sort_ == SORT_WILDCARD_BY_ALIGNMENT
1289 || this->section_sort_ == SORT_WILDCARD_BY_NAME_BY_ALIGNMENT
1290 || this->section_sort_ == SORT_WILDCARD_BY_ALIGNMENT_BY_NAME)
1292 if (isi1.addralign() != isi2.addralign())
1293 return isi1.addralign() < isi2.addralign();
1295 if (this->filename_sort_ == SORT_WILDCARD_BY_NAME)
1297 if (isi1.relobj()->name() != isi2.relobj()->name())
1298 return (isi1.relobj()->name() < isi2.relobj()->name());
1301 // Otherwise we leave them in the same order.
1305 // Set the section address. Look in INPUT_SECTIONS for sections which
1306 // match this spec, sort them as specified, and add them to the output
1310 Output_section_element_input::set_section_addresses(
1313 Output_section* output_section,
1315 uint64_t* dot_value,
1317 Output_section** dot_section,
1319 Input_section_list* input_sections)
1321 // We build a list of sections which match each
1322 // Input_section_pattern.
1324 typedef std::vector<std::vector<Input_section_info> > Matching_sections;
1325 size_t input_pattern_count = this->input_section_patterns_.size();
1326 if (input_pattern_count == 0)
1327 input_pattern_count = 1;
1328 Matching_sections matching_sections(input_pattern_count);
1330 // Look through the list of sections for this output section. Add
1331 // each one which matches to one of the elements of
1332 // MATCHING_SECTIONS.
1334 Input_section_list::iterator p = input_sections->begin();
1335 while (p != input_sections->end())
1337 Relobj* relobj = p->relobj();
1338 unsigned int shndx = p->shndx();
1339 Input_section_info isi(*p);
1341 // Calling section_name and section_addralign is not very
1344 // Lock the object so that we can get information about the
1345 // section. This is OK since we know we are single-threaded
1348 const Task* task = reinterpret_cast<const Task*>(-1);
1349 Task_lock_obj<Object> tl(task, relobj);
1351 isi.set_section_name(relobj->section_name(shndx));
1352 if (p->is_relaxed_input_section())
1354 // We use current data size because relxed section sizes may not
1355 // have finalized yet.
1356 isi.set_size(p->relaxed_input_section()->current_data_size());
1357 isi.set_addralign(p->relaxed_input_section()->addralign());
1361 isi.set_size(relobj->section_size(shndx));
1362 isi.set_addralign(relobj->section_addralign(shndx));
1366 if (!this->match_file_name(relobj->name().c_str()))
1368 else if (this->input_section_patterns_.empty())
1370 matching_sections[0].push_back(isi);
1371 p = input_sections->erase(p);
1376 for (i = 0; i < input_pattern_count; ++i)
1378 const Input_section_pattern&
1379 isp(this->input_section_patterns_[i]);
1380 if (match(isi.section_name().c_str(), isp.pattern.c_str(),
1381 isp.pattern_is_wildcard))
1385 if (i >= this->input_section_patterns_.size())
1389 matching_sections[i].push_back(isi);
1390 p = input_sections->erase(p);
1395 // Look through MATCHING_SECTIONS. Sort each one as specified,
1396 // using a stable sort so that we get the default order when
1397 // sections are otherwise equal. Add each input section to the
1400 uint64_t dot = *dot_value;
1401 for (size_t i = 0; i < input_pattern_count; ++i)
1403 if (matching_sections[i].empty())
1406 gold_assert(output_section != NULL);
1408 const Input_section_pattern& isp(this->input_section_patterns_[i]);
1409 if (isp.sort != SORT_WILDCARD_NONE
1410 || this->filename_sort_ != SORT_WILDCARD_NONE)
1411 std::stable_sort(matching_sections[i].begin(),
1412 matching_sections[i].end(),
1413 Input_section_sorter(this->filename_sort_,
1416 for (std::vector<Input_section_info>::const_iterator p =
1417 matching_sections[i].begin();
1418 p != matching_sections[i].end();
1421 // Override the original address alignment if SUBALIGN is specified
1422 // and is greater than the original alignment. We need to make a
1423 // copy of the input section to modify the alignment.
1424 Output_section::Input_section sis(p->input_section());
1426 uint64_t this_subalign = sis.addralign();
1427 if (!sis.is_input_section())
1428 sis.output_section_data()->finalize_data_size();
1429 uint64_t data_size = sis.data_size();
1430 if (this_subalign < subalign)
1432 this_subalign = subalign;
1433 sis.set_addralign(subalign);
1436 uint64_t address = align_address(dot, this_subalign);
1438 if (address > dot && !fill->empty())
1440 section_size_type length =
1441 convert_to_section_size_type(address - dot);
1442 std::string this_fill = this->get_fill_string(fill, length);
1443 Output_section_data* posd = new Output_data_const(this_fill, 0);
1444 output_section->add_output_section_data(posd);
1445 layout->new_output_section_data_from_script(posd);
1448 output_section->add_script_input_section(sis);
1449 dot = address + data_size;
1453 // An SHF_TLS/SHT_NOBITS section does not take up any
1455 if (output_section == NULL
1456 || (output_section->flags() & elfcpp::SHF_TLS) == 0
1457 || output_section->type() != elfcpp::SHT_NOBITS)
1460 this->final_dot_value_ = *dot_value;
1461 this->final_dot_section_ = *dot_section;
1464 // Print for debugging.
1467 Output_section_element_input::print(FILE* f) const
1472 fprintf(f, "KEEP(");
1474 if (!this->filename_pattern_.empty())
1476 bool need_close_paren = false;
1477 switch (this->filename_sort_)
1479 case SORT_WILDCARD_NONE:
1481 case SORT_WILDCARD_BY_NAME:
1482 fprintf(f, "SORT_BY_NAME(");
1483 need_close_paren = true;
1489 fprintf(f, "%s", this->filename_pattern_.c_str());
1491 if (need_close_paren)
1495 if (!this->input_section_patterns_.empty()
1496 || !this->filename_exclusions_.empty())
1500 bool need_space = false;
1501 if (!this->filename_exclusions_.empty())
1503 fprintf(f, "EXCLUDE_FILE(");
1504 bool need_comma = false;
1505 for (Filename_exclusions::const_iterator p =
1506 this->filename_exclusions_.begin();
1507 p != this->filename_exclusions_.end();
1512 fprintf(f, "%s", p->first.c_str());
1519 for (Input_section_patterns::const_iterator p =
1520 this->input_section_patterns_.begin();
1521 p != this->input_section_patterns_.end();
1527 int close_parens = 0;
1530 case SORT_WILDCARD_NONE:
1532 case SORT_WILDCARD_BY_NAME:
1533 fprintf(f, "SORT_BY_NAME(");
1536 case SORT_WILDCARD_BY_ALIGNMENT:
1537 fprintf(f, "SORT_BY_ALIGNMENT(");
1540 case SORT_WILDCARD_BY_NAME_BY_ALIGNMENT:
1541 fprintf(f, "SORT_BY_NAME(SORT_BY_ALIGNMENT(");
1544 case SORT_WILDCARD_BY_ALIGNMENT_BY_NAME:
1545 fprintf(f, "SORT_BY_ALIGNMENT(SORT_BY_NAME(");
1552 fprintf(f, "%s", p->pattern.c_str());
1554 for (int i = 0; i < close_parens; ++i)
1569 // An output section.
1571 class Output_section_definition : public Sections_element
1574 typedef Output_section_element::Input_section_list Input_section_list;
1576 Output_section_definition(const char* name, size_t namelen,
1577 const Parser_output_section_header* header);
1579 // Finish the output section with the information in the trailer.
1581 finish(const Parser_output_section_trailer* trailer);
1583 // Add a symbol to be defined.
1585 add_symbol_assignment(const char* name, size_t length, Expression* value,
1586 bool provide, bool hidden);
1588 // Add an assignment to the special dot symbol.
1590 add_dot_assignment(Expression* value);
1592 // Add an assertion.
1594 add_assertion(Expression* check, const char* message, size_t messagelen);
1596 // Add a data item to the current output section.
1598 add_data(int size, bool is_signed, Expression* val);
1600 // Add a setting for the fill value.
1602 add_fill(Expression* val);
1604 // Add an input section specification.
1606 add_input_section(const Input_section_spec* spec, bool keep);
1608 // Return whether the output section is relro.
1611 { return this->is_relro_; }
1613 // Record that the output section is relro.
1616 { this->is_relro_ = true; }
1618 // Create any required output sections.
1620 create_sections(Layout*);
1622 // Add any symbols being defined to the symbol table.
1624 add_symbols_to_table(Symbol_table* symtab);
1626 // Finalize symbols and check assertions.
1628 finalize_symbols(Symbol_table*, const Layout*, uint64_t*);
1630 // Return the output section name to use for an input file name and
1633 output_section_name(const char* file_name, const char* section_name,
1634 Output_section***, Script_sections::Section_type*);
1636 // Initialize OSP with an output section.
1638 orphan_section_init(Orphan_section_placement* osp,
1639 Script_sections::Elements_iterator p)
1640 { osp->output_section_init(this->name_, this->output_section_, p); }
1642 // Set the section address.
1644 set_section_addresses(Symbol_table* symtab, Layout* layout,
1645 uint64_t* dot_value, uint64_t*,
1646 uint64_t* load_address);
1648 // Check a constraint (ONLY_IF_RO, etc.) on an output section. If
1649 // this section is constrained, and the input sections do not match,
1650 // return the constraint, and set *POSD.
1652 check_constraint(Output_section_definition** posd);
1654 // See if this is the alternate output section for a constrained
1655 // output section. If it is, transfer the Output_section and return
1656 // true. Otherwise return false.
1658 alternate_constraint(Output_section_definition*, Section_constraint);
1660 // Get the list of segments to use for an allocated section when
1661 // using a PHDRS clause.
1663 allocate_to_segment(String_list** phdrs_list, bool* orphan);
1665 // Look for an output section by name and return the address, the
1666 // load address, the alignment, and the size. This is used when an
1667 // expression refers to an output section which was not actually
1668 // created. This returns true if the section was found, false
1671 get_output_section_info(const char*, uint64_t*, uint64_t*, uint64_t*,
1674 // Return the associated Output_section if there is one.
1676 get_output_section() const
1677 { return this->output_section_; }
1679 // Print the contents to the FILE. This is for debugging.
1683 // Return the output section type if specified or Script_sections::ST_NONE.
1684 Script_sections::Section_type
1685 section_type() const;
1689 script_section_type_name(Script_section_type);
1691 typedef std::vector<Output_section_element*> Output_section_elements;
1693 // The output section name.
1695 // The address. This may be NULL.
1696 Expression* address_;
1697 // The load address. This may be NULL.
1698 Expression* load_address_;
1699 // The alignment. This may be NULL.
1701 // The input section alignment. This may be NULL.
1702 Expression* subalign_;
1703 // The constraint, if any.
1704 Section_constraint constraint_;
1705 // The fill value. This may be NULL.
1707 // The list of segments this section should go into. This may be
1709 String_list* phdrs_;
1710 // The list of elements defining the section.
1711 Output_section_elements elements_;
1712 // The Output_section created for this definition. This will be
1713 // NULL if none was created.
1714 Output_section* output_section_;
1715 // The address after it has been evaluated.
1716 uint64_t evaluated_address_;
1717 // The load address after it has been evaluated.
1718 uint64_t evaluated_load_address_;
1719 // The alignment after it has been evaluated.
1720 uint64_t evaluated_addralign_;
1721 // The output section is relro.
1723 // The output section type if specified.
1724 enum Script_section_type script_section_type_;
1729 Output_section_definition::Output_section_definition(
1732 const Parser_output_section_header* header)
1733 : name_(name, namelen),
1734 address_(header->address),
1735 load_address_(header->load_address),
1736 align_(header->align),
1737 subalign_(header->subalign),
1738 constraint_(header->constraint),
1742 output_section_(NULL),
1743 evaluated_address_(0),
1744 evaluated_load_address_(0),
1745 evaluated_addralign_(0),
1747 script_section_type_(header->section_type)
1751 // Finish an output section.
1754 Output_section_definition::finish(const Parser_output_section_trailer* trailer)
1756 this->fill_ = trailer->fill;
1757 this->phdrs_ = trailer->phdrs;
1760 // Add a symbol to be defined.
1763 Output_section_definition::add_symbol_assignment(const char* name,
1769 Output_section_element* p = new Output_section_element_assignment(name,
1774 this->elements_.push_back(p);
1777 // Add an assignment to the special dot symbol.
1780 Output_section_definition::add_dot_assignment(Expression* value)
1782 Output_section_element* p = new Output_section_element_dot_assignment(value);
1783 this->elements_.push_back(p);
1786 // Add an assertion.
1789 Output_section_definition::add_assertion(Expression* check,
1790 const char* message,
1793 Output_section_element* p = new Output_section_element_assertion(check,
1796 this->elements_.push_back(p);
1799 // Add a data item to the current output section.
1802 Output_section_definition::add_data(int size, bool is_signed, Expression* val)
1804 Output_section_element* p = new Output_section_element_data(size, is_signed,
1806 this->elements_.push_back(p);
1809 // Add a setting for the fill value.
1812 Output_section_definition::add_fill(Expression* val)
1814 Output_section_element* p = new Output_section_element_fill(val);
1815 this->elements_.push_back(p);
1818 // Add an input section specification.
1821 Output_section_definition::add_input_section(const Input_section_spec* spec,
1824 Output_section_element* p = new Output_section_element_input(spec, keep);
1825 this->elements_.push_back(p);
1828 // Create any required output sections. We need an output section if
1829 // there is a data statement here.
1832 Output_section_definition::create_sections(Layout* layout)
1834 if (this->output_section_ != NULL)
1836 for (Output_section_elements::const_iterator p = this->elements_.begin();
1837 p != this->elements_.end();
1840 if ((*p)->needs_output_section())
1842 const char* name = this->name_.c_str();
1843 this->output_section_ =
1844 layout->make_output_section_for_script(name, this->section_type());
1850 // Add any symbols being defined to the symbol table.
1853 Output_section_definition::add_symbols_to_table(Symbol_table* symtab)
1855 for (Output_section_elements::iterator p = this->elements_.begin();
1856 p != this->elements_.end();
1858 (*p)->add_symbols_to_table(symtab);
1861 // Finalize symbols and check assertions.
1864 Output_section_definition::finalize_symbols(Symbol_table* symtab,
1865 const Layout* layout,
1866 uint64_t* dot_value)
1868 if (this->output_section_ != NULL)
1869 *dot_value = this->output_section_->address();
1872 uint64_t address = *dot_value;
1873 if (this->address_ != NULL)
1875 Output_section* dummy;
1876 address = this->address_->eval_with_dot(symtab, layout, true,
1880 if (this->align_ != NULL)
1882 Output_section* dummy;
1883 uint64_t align = this->align_->eval_with_dot(symtab, layout, true,
1887 address = align_address(address, align);
1889 *dot_value = address;
1892 Output_section* dot_section = this->output_section_;
1893 for (Output_section_elements::iterator p = this->elements_.begin();
1894 p != this->elements_.end();
1896 (*p)->finalize_symbols(symtab, layout, dot_value, &dot_section);
1899 // Return the output section name to use for an input section name.
1902 Output_section_definition::output_section_name(
1903 const char* file_name,
1904 const char* section_name,
1905 Output_section*** slot,
1906 Script_sections::Section_type *psection_type)
1908 // Ask each element whether it matches NAME.
1909 for (Output_section_elements::const_iterator p = this->elements_.begin();
1910 p != this->elements_.end();
1913 if ((*p)->match_name(file_name, section_name))
1915 // We found a match for NAME, which means that it should go
1916 // into this output section.
1917 *slot = &this->output_section_;
1918 *psection_type = this->section_type();
1919 return this->name_.c_str();
1923 // We don't know about this section name.
1927 // Set the section address. Note that the OUTPUT_SECTION_ field will
1928 // be NULL if no input sections were mapped to this output section.
1929 // We still have to adjust dot and process symbol assignments.
1932 Output_section_definition::set_section_addresses(Symbol_table* symtab,
1934 uint64_t* dot_value,
1935 uint64_t* dot_alignment,
1936 uint64_t* load_address)
1939 uint64_t old_dot_value = *dot_value;
1940 uint64_t old_load_address = *load_address;
1942 if (this->address_ == NULL)
1943 address = *dot_value;
1946 Output_section* dummy;
1947 address = this->address_->eval_with_dot(symtab, layout, true,
1948 *dot_value, NULL, &dummy,
1953 if (this->align_ == NULL)
1955 if (this->output_section_ == NULL)
1958 align = this->output_section_->addralign();
1962 Output_section* align_section;
1963 align = this->align_->eval_with_dot(symtab, layout, true, *dot_value,
1964 NULL, &align_section, NULL);
1965 if (align_section != NULL)
1966 gold_warning(_("alignment of section %s is not absolute"),
1967 this->name_.c_str());
1968 if (this->output_section_ != NULL)
1969 this->output_section_->set_addralign(align);
1972 address = align_address(address, align);
1974 uint64_t start_address = address;
1976 *dot_value = address;
1978 // Except for NOLOAD sections, the address of non-SHF_ALLOC sections is
1979 // forced to zero, regardless of what the linker script wants.
1980 if (this->output_section_ != NULL
1981 && ((this->output_section_->flags() & elfcpp::SHF_ALLOC) != 0
1982 || this->output_section_->is_noload()))
1983 this->output_section_->set_address(address);
1985 this->evaluated_address_ = address;
1986 this->evaluated_addralign_ = align;
1988 if (this->load_address_ == NULL)
1989 this->evaluated_load_address_ = address;
1992 Output_section* dummy;
1994 this->load_address_->eval_with_dot(symtab, layout, true, *dot_value,
1995 this->output_section_, &dummy,
1997 if (this->output_section_ != NULL)
1998 this->output_section_->set_load_address(laddr);
1999 this->evaluated_load_address_ = laddr;
2003 if (this->subalign_ == NULL)
2007 Output_section* subalign_section;
2008 subalign = this->subalign_->eval_with_dot(symtab, layout, true,
2010 &subalign_section, NULL);
2011 if (subalign_section != NULL)
2012 gold_warning(_("subalign of section %s is not absolute"),
2013 this->name_.c_str());
2017 if (this->fill_ != NULL)
2019 // FIXME: The GNU linker supports fill values of arbitrary
2021 Output_section* fill_section;
2022 uint64_t fill_val = this->fill_->eval_with_dot(symtab, layout, true,
2024 NULL, &fill_section,
2026 if (fill_section != NULL)
2027 gold_warning(_("fill of section %s is not absolute"),
2028 this->name_.c_str());
2029 unsigned char fill_buff[4];
2030 elfcpp::Swap_unaligned<32, true>::writeval(fill_buff, fill_val);
2031 fill.assign(reinterpret_cast<char*>(fill_buff), 4);
2034 Input_section_list input_sections;
2035 if (this->output_section_ != NULL)
2037 // Get the list of input sections attached to this output
2038 // section. This will leave the output section with only
2039 // Output_section_data entries.
2040 address += this->output_section_->get_input_sections(address,
2043 *dot_value = address;
2046 Output_section* dot_section = this->output_section_;
2047 for (Output_section_elements::iterator p = this->elements_.begin();
2048 p != this->elements_.end();
2050 (*p)->set_section_addresses(symtab, layout, this->output_section_,
2051 subalign, dot_value, dot_alignment,
2052 &dot_section, &fill, &input_sections);
2054 gold_assert(input_sections.empty());
2056 if (this->load_address_ == NULL || this->output_section_ == NULL)
2057 *load_address = *dot_value;
2059 *load_address = (this->output_section_->load_address()
2060 + (*dot_value - start_address));
2062 if (this->output_section_ != NULL)
2064 if (this->is_relro_)
2065 this->output_section_->set_is_relro();
2067 this->output_section_->clear_is_relro();
2069 // If this is a NOLOAD section, keep dot and load address unchanged.
2070 if (this->output_section_->is_noload())
2072 *dot_value = old_dot_value;
2073 *load_address = old_load_address;
2078 // Check a constraint (ONLY_IF_RO, etc.) on an output section. If
2079 // this section is constrained, and the input sections do not match,
2080 // return the constraint, and set *POSD.
2083 Output_section_definition::check_constraint(Output_section_definition** posd)
2085 switch (this->constraint_)
2087 case CONSTRAINT_NONE:
2088 return CONSTRAINT_NONE;
2090 case CONSTRAINT_ONLY_IF_RO:
2091 if (this->output_section_ != NULL
2092 && (this->output_section_->flags() & elfcpp::SHF_WRITE) != 0)
2095 return CONSTRAINT_ONLY_IF_RO;
2097 return CONSTRAINT_NONE;
2099 case CONSTRAINT_ONLY_IF_RW:
2100 if (this->output_section_ != NULL
2101 && (this->output_section_->flags() & elfcpp::SHF_WRITE) == 0)
2104 return CONSTRAINT_ONLY_IF_RW;
2106 return CONSTRAINT_NONE;
2108 case CONSTRAINT_SPECIAL:
2109 if (this->output_section_ != NULL)
2110 gold_error(_("SPECIAL constraints are not implemented"));
2111 return CONSTRAINT_NONE;
2118 // See if this is the alternate output section for a constrained
2119 // output section. If it is, transfer the Output_section and return
2120 // true. Otherwise return false.
2123 Output_section_definition::alternate_constraint(
2124 Output_section_definition* posd,
2125 Section_constraint constraint)
2127 if (this->name_ != posd->name_)
2132 case CONSTRAINT_ONLY_IF_RO:
2133 if (this->constraint_ != CONSTRAINT_ONLY_IF_RW)
2137 case CONSTRAINT_ONLY_IF_RW:
2138 if (this->constraint_ != CONSTRAINT_ONLY_IF_RO)
2146 // We have found the alternate constraint. We just need to move
2147 // over the Output_section. When constraints are used properly,
2148 // THIS should not have an output_section pointer, as all the input
2149 // sections should have matched the other definition.
2151 if (this->output_section_ != NULL)
2152 gold_error(_("mismatched definition for constrained sections"));
2154 this->output_section_ = posd->output_section_;
2155 posd->output_section_ = NULL;
2157 if (this->is_relro_)
2158 this->output_section_->set_is_relro();
2160 this->output_section_->clear_is_relro();
2165 // Get the list of segments to use for an allocated section when using
2169 Output_section_definition::allocate_to_segment(String_list** phdrs_list,
2172 // Update phdrs_list even if we don't have an output section. It
2173 // might be used by the following sections.
2174 if (this->phdrs_ != NULL)
2175 *phdrs_list = this->phdrs_;
2177 if (this->output_section_ == NULL)
2179 if ((this->output_section_->flags() & elfcpp::SHF_ALLOC) == 0)
2182 return this->output_section_;
2185 // Look for an output section by name and return the address, the load
2186 // address, the alignment, and the size. This is used when an
2187 // expression refers to an output section which was not actually
2188 // created. This returns true if the section was found, false
2192 Output_section_definition::get_output_section_info(const char* name,
2194 uint64_t* load_address,
2195 uint64_t* addralign,
2196 uint64_t* size) const
2198 if (this->name_ != name)
2201 if (this->output_section_ != NULL)
2203 *address = this->output_section_->address();
2204 if (this->output_section_->has_load_address())
2205 *load_address = this->output_section_->load_address();
2207 *load_address = *address;
2208 *addralign = this->output_section_->addralign();
2209 *size = this->output_section_->current_data_size();
2213 *address = this->evaluated_address_;
2214 *load_address = this->evaluated_load_address_;
2215 *addralign = this->evaluated_addralign_;
2222 // Print for debugging.
2225 Output_section_definition::print(FILE* f) const
2227 fprintf(f, " %s ", this->name_.c_str());
2229 if (this->address_ != NULL)
2231 this->address_->print(f);
2235 if (this->script_section_type_ != SCRIPT_SECTION_TYPE_NONE)
2237 this->script_section_type_name(this->script_section_type_));
2241 if (this->load_address_ != NULL)
2244 this->load_address_->print(f);
2248 if (this->align_ != NULL)
2250 fprintf(f, "ALIGN(");
2251 this->align_->print(f);
2255 if (this->subalign_ != NULL)
2257 fprintf(f, "SUBALIGN(");
2258 this->subalign_->print(f);
2264 for (Output_section_elements::const_iterator p = this->elements_.begin();
2265 p != this->elements_.end();
2271 if (this->fill_ != NULL)
2274 this->fill_->print(f);
2277 if (this->phdrs_ != NULL)
2279 for (String_list::const_iterator p = this->phdrs_->begin();
2280 p != this->phdrs_->end();
2282 fprintf(f, " :%s", p->c_str());
2288 Script_sections::Section_type
2289 Output_section_definition::section_type() const
2291 switch (this->script_section_type_)
2293 case SCRIPT_SECTION_TYPE_NONE:
2294 return Script_sections::ST_NONE;
2295 case SCRIPT_SECTION_TYPE_NOLOAD:
2296 return Script_sections::ST_NOLOAD;
2297 case SCRIPT_SECTION_TYPE_COPY:
2298 case SCRIPT_SECTION_TYPE_DSECT:
2299 case SCRIPT_SECTION_TYPE_INFO:
2300 case SCRIPT_SECTION_TYPE_OVERLAY:
2301 // There are not really support so we treat them as ST_NONE. The
2302 // parse should have issued errors for them already.
2303 return Script_sections::ST_NONE;
2309 // Return the name of a script section type.
2312 Output_section_definition::script_section_type_name (
2313 Script_section_type script_section_type)
2315 switch (script_section_type)
2317 case SCRIPT_SECTION_TYPE_NONE:
2319 case SCRIPT_SECTION_TYPE_NOLOAD:
2321 case SCRIPT_SECTION_TYPE_DSECT:
2323 case SCRIPT_SECTION_TYPE_COPY:
2325 case SCRIPT_SECTION_TYPE_INFO:
2327 case SCRIPT_SECTION_TYPE_OVERLAY:
2334 // An output section created to hold orphaned input sections. These
2335 // do not actually appear in linker scripts. However, for convenience
2336 // when setting the output section addresses, we put a marker to these
2337 // sections in the appropriate place in the list of SECTIONS elements.
2339 class Orphan_output_section : public Sections_element
2342 Orphan_output_section(Output_section* os)
2346 // Return whether the orphan output section is relro. We can just
2347 // check the output section because we always set the flag, if
2348 // needed, just after we create the Orphan_output_section.
2351 { return this->os_->is_relro(); }
2353 // Initialize OSP with an output section. This should have been
2356 orphan_section_init(Orphan_section_placement*,
2357 Script_sections::Elements_iterator)
2358 { gold_unreachable(); }
2360 // Set section addresses.
2362 set_section_addresses(Symbol_table*, Layout*, uint64_t*, uint64_t*,
2365 // Get the list of segments to use for an allocated section when
2366 // using a PHDRS clause.
2368 allocate_to_segment(String_list**, bool*);
2370 // Return the associated Output_section.
2372 get_output_section() const
2373 { return this->os_; }
2375 // Print for debugging.
2377 print(FILE* f) const
2379 fprintf(f, " marker for orphaned output section %s\n",
2384 Output_section* os_;
2387 // Set section addresses.
2390 Orphan_output_section::set_section_addresses(Symbol_table*, Layout*,
2391 uint64_t* dot_value,
2393 uint64_t* load_address)
2395 typedef std::list<Output_section::Input_section> Input_section_list;
2397 bool have_load_address = *load_address != *dot_value;
2399 uint64_t address = *dot_value;
2400 address = align_address(address, this->os_->addralign());
2402 if ((this->os_->flags() & elfcpp::SHF_ALLOC) != 0)
2404 this->os_->set_address(address);
2405 if (have_load_address)
2406 this->os_->set_load_address(align_address(*load_address,
2407 this->os_->addralign()));
2410 Input_section_list input_sections;
2411 address += this->os_->get_input_sections(address, "", &input_sections);
2413 for (Input_section_list::iterator p = input_sections.begin();
2414 p != input_sections.end();
2417 uint64_t addralign = p->addralign();
2418 if (!p->is_input_section())
2419 p->output_section_data()->finalize_data_size();
2420 uint64_t size = p->data_size();
2421 address = align_address(address, addralign);
2422 this->os_->add_script_input_section(*p);
2426 // An SHF_TLS/SHT_NOBITS section does not take up any address space.
2427 if (this->os_ == NULL
2428 || (this->os_->flags() & elfcpp::SHF_TLS) == 0
2429 || this->os_->type() != elfcpp::SHT_NOBITS)
2431 if (!have_load_address)
2432 *load_address = address;
2434 *load_address += address - *dot_value;
2436 *dot_value = address;
2440 // Get the list of segments to use for an allocated section when using
2441 // a PHDRS clause. If this is an allocated section, return the
2442 // Output_section. We don't change the list of segments.
2445 Orphan_output_section::allocate_to_segment(String_list**, bool* orphan)
2447 if ((this->os_->flags() & elfcpp::SHF_ALLOC) == 0)
2453 // Class Phdrs_element. A program header from a PHDRS clause.
2458 Phdrs_element(const char* name, size_t namelen, unsigned int type,
2459 bool includes_filehdr, bool includes_phdrs,
2460 bool is_flags_valid, unsigned int flags,
2461 Expression* load_address)
2462 : name_(name, namelen), type_(type), includes_filehdr_(includes_filehdr),
2463 includes_phdrs_(includes_phdrs), is_flags_valid_(is_flags_valid),
2464 flags_(flags), load_address_(load_address), load_address_value_(0),
2468 // Return the name of this segment.
2471 { return this->name_; }
2473 // Return the type of the segment.
2476 { return this->type_; }
2478 // Whether to include the file header.
2480 includes_filehdr() const
2481 { return this->includes_filehdr_; }
2483 // Whether to include the program headers.
2485 includes_phdrs() const
2486 { return this->includes_phdrs_; }
2488 // Return whether there is a load address.
2490 has_load_address() const
2491 { return this->load_address_ != NULL; }
2493 // Evaluate the load address expression if there is one.
2495 eval_load_address(Symbol_table* symtab, Layout* layout)
2497 if (this->load_address_ != NULL)
2498 this->load_address_value_ = this->load_address_->eval(symtab, layout,
2502 // Return the load address.
2504 load_address() const
2506 gold_assert(this->load_address_ != NULL);
2507 return this->load_address_value_;
2510 // Create the segment.
2512 create_segment(Layout* layout)
2514 this->segment_ = layout->make_output_segment(this->type_, this->flags_);
2515 return this->segment_;
2518 // Return the segment.
2521 { return this->segment_; }
2523 // Release the segment.
2526 { this->segment_ = NULL; }
2528 // Set the segment flags if appropriate.
2530 set_flags_if_valid()
2532 if (this->is_flags_valid_)
2533 this->segment_->set_flags(this->flags_);
2536 // Print for debugging.
2541 // The name used in the script.
2543 // The type of the segment (PT_LOAD, etc.).
2545 // Whether this segment includes the file header.
2546 bool includes_filehdr_;
2547 // Whether this segment includes the section headers.
2548 bool includes_phdrs_;
2549 // Whether the flags were explicitly specified.
2550 bool is_flags_valid_;
2551 // The flags for this segment (PF_R, etc.) if specified.
2552 unsigned int flags_;
2553 // The expression for the load address for this segment. This may
2555 Expression* load_address_;
2556 // The actual load address from evaluating the expression.
2557 uint64_t load_address_value_;
2558 // The segment itself.
2559 Output_segment* segment_;
2562 // Print for debugging.
2565 Phdrs_element::print(FILE* f) const
2567 fprintf(f, " %s 0x%x", this->name_.c_str(), this->type_);
2568 if (this->includes_filehdr_)
2569 fprintf(f, " FILEHDR");
2570 if (this->includes_phdrs_)
2571 fprintf(f, " PHDRS");
2572 if (this->is_flags_valid_)
2573 fprintf(f, " FLAGS(%u)", this->flags_);
2574 if (this->load_address_ != NULL)
2577 this->load_address_->print(f);
2583 // Class Script_sections.
2585 Script_sections::Script_sections()
2586 : saw_sections_clause_(false),
2587 in_sections_clause_(false),
2588 sections_elements_(NULL),
2589 output_section_(NULL),
2590 phdrs_elements_(NULL),
2591 orphan_section_placement_(NULL),
2592 data_segment_align_start_(),
2593 saw_data_segment_align_(false),
2594 saw_relro_end_(false),
2595 saw_segment_start_expression_(false)
2599 // Start a SECTIONS clause.
2602 Script_sections::start_sections()
2604 gold_assert(!this->in_sections_clause_ && this->output_section_ == NULL);
2605 this->saw_sections_clause_ = true;
2606 this->in_sections_clause_ = true;
2607 if (this->sections_elements_ == NULL)
2608 this->sections_elements_ = new Sections_elements;
2611 // Finish a SECTIONS clause.
2614 Script_sections::finish_sections()
2616 gold_assert(this->in_sections_clause_ && this->output_section_ == NULL);
2617 this->in_sections_clause_ = false;
2620 // Add a symbol to be defined.
2623 Script_sections::add_symbol_assignment(const char* name, size_t length,
2624 Expression* val, bool provide,
2627 if (this->output_section_ != NULL)
2628 this->output_section_->add_symbol_assignment(name, length, val,
2632 Sections_element* p = new Sections_element_assignment(name, length,
2635 this->sections_elements_->push_back(p);
2639 // Add an assignment to the special dot symbol.
2642 Script_sections::add_dot_assignment(Expression* val)
2644 if (this->output_section_ != NULL)
2645 this->output_section_->add_dot_assignment(val);
2648 // The GNU linker permits assignments to . to appears outside of
2649 // a SECTIONS clause, and treats it as appearing inside, so
2650 // sections_elements_ may be NULL here.
2651 if (this->sections_elements_ == NULL)
2653 this->sections_elements_ = new Sections_elements;
2654 this->saw_sections_clause_ = true;
2657 Sections_element* p = new Sections_element_dot_assignment(val);
2658 this->sections_elements_->push_back(p);
2662 // Add an assertion.
2665 Script_sections::add_assertion(Expression* check, const char* message,
2668 if (this->output_section_ != NULL)
2669 this->output_section_->add_assertion(check, message, messagelen);
2672 Sections_element* p = new Sections_element_assertion(check, message,
2674 this->sections_elements_->push_back(p);
2678 // Start processing entries for an output section.
2681 Script_sections::start_output_section(
2684 const Parser_output_section_header *header)
2686 Output_section_definition* posd = new Output_section_definition(name,
2689 this->sections_elements_->push_back(posd);
2690 gold_assert(this->output_section_ == NULL);
2691 this->output_section_ = posd;
2694 // Stop processing entries for an output section.
2697 Script_sections::finish_output_section(
2698 const Parser_output_section_trailer* trailer)
2700 gold_assert(this->output_section_ != NULL);
2701 this->output_section_->finish(trailer);
2702 this->output_section_ = NULL;
2705 // Add a data item to the current output section.
2708 Script_sections::add_data(int size, bool is_signed, Expression* val)
2710 gold_assert(this->output_section_ != NULL);
2711 this->output_section_->add_data(size, is_signed, val);
2714 // Add a fill value setting to the current output section.
2717 Script_sections::add_fill(Expression* val)
2719 gold_assert(this->output_section_ != NULL);
2720 this->output_section_->add_fill(val);
2723 // Add an input section specification to the current output section.
2726 Script_sections::add_input_section(const Input_section_spec* spec, bool keep)
2728 gold_assert(this->output_section_ != NULL);
2729 this->output_section_->add_input_section(spec, keep);
2732 // This is called when we see DATA_SEGMENT_ALIGN. It means that any
2733 // subsequent output sections may be relro.
2736 Script_sections::data_segment_align()
2738 if (this->saw_data_segment_align_)
2739 gold_error(_("DATA_SEGMENT_ALIGN may only appear once in a linker script"));
2740 gold_assert(!this->sections_elements_->empty());
2741 Sections_elements::iterator p = this->sections_elements_->end();
2743 this->data_segment_align_start_ = p;
2744 this->saw_data_segment_align_ = true;
2747 // This is called when we see DATA_SEGMENT_RELRO_END. It means that
2748 // any output sections seen since DATA_SEGMENT_ALIGN are relro.
2751 Script_sections::data_segment_relro_end()
2753 if (this->saw_relro_end_)
2754 gold_error(_("DATA_SEGMENT_RELRO_END may only appear once "
2755 "in a linker script"));
2756 this->saw_relro_end_ = true;
2758 if (!this->saw_data_segment_align_)
2759 gold_error(_("DATA_SEGMENT_RELRO_END must follow DATA_SEGMENT_ALIGN"));
2762 Sections_elements::iterator p = this->data_segment_align_start_;
2763 for (++p; p != this->sections_elements_->end(); ++p)
2764 (*p)->set_is_relro();
2768 // Create any required sections.
2771 Script_sections::create_sections(Layout* layout)
2773 if (!this->saw_sections_clause_)
2775 for (Sections_elements::iterator p = this->sections_elements_->begin();
2776 p != this->sections_elements_->end();
2778 (*p)->create_sections(layout);
2781 // Add any symbols we are defining to the symbol table.
2784 Script_sections::add_symbols_to_table(Symbol_table* symtab)
2786 if (!this->saw_sections_clause_)
2788 for (Sections_elements::iterator p = this->sections_elements_->begin();
2789 p != this->sections_elements_->end();
2791 (*p)->add_symbols_to_table(symtab);
2794 // Finalize symbols and check assertions.
2797 Script_sections::finalize_symbols(Symbol_table* symtab, const Layout* layout)
2799 if (!this->saw_sections_clause_)
2801 uint64_t dot_value = 0;
2802 for (Sections_elements::iterator p = this->sections_elements_->begin();
2803 p != this->sections_elements_->end();
2805 (*p)->finalize_symbols(symtab, layout, &dot_value);
2808 // Return the name of the output section to use for an input file name
2809 // and section name.
2812 Script_sections::output_section_name(
2813 const char* file_name,
2814 const char* section_name,
2815 Output_section*** output_section_slot,
2816 Script_sections::Section_type *psection_type)
2818 for (Sections_elements::const_iterator p = this->sections_elements_->begin();
2819 p != this->sections_elements_->end();
2822 const char* ret = (*p)->output_section_name(file_name, section_name,
2823 output_section_slot,
2828 // The special name /DISCARD/ means that the input section
2829 // should be discarded.
2830 if (strcmp(ret, "/DISCARD/") == 0)
2832 *output_section_slot = NULL;
2833 *psection_type = Script_sections::ST_NONE;
2840 // If we couldn't find a mapping for the name, the output section
2841 // gets the name of the input section.
2843 *output_section_slot = NULL;
2844 *psection_type = Script_sections::ST_NONE;
2846 return section_name;
2849 // Place a marker for an orphan output section into the SECTIONS
2853 Script_sections::place_orphan(Output_section* os)
2855 Orphan_section_placement* osp = this->orphan_section_placement_;
2858 // Initialize the Orphan_section_placement structure.
2859 osp = new Orphan_section_placement();
2860 for (Sections_elements::iterator p = this->sections_elements_->begin();
2861 p != this->sections_elements_->end();
2863 (*p)->orphan_section_init(osp, p);
2864 gold_assert(!this->sections_elements_->empty());
2865 Sections_elements::iterator last = this->sections_elements_->end();
2867 osp->last_init(last);
2868 this->orphan_section_placement_ = osp;
2871 Orphan_output_section* orphan = new Orphan_output_section(os);
2873 // Look for where to put ORPHAN.
2874 Sections_elements::iterator* where;
2875 if (osp->find_place(os, &where))
2877 if ((**where)->is_relro())
2880 os->clear_is_relro();
2882 // We want to insert ORPHAN after *WHERE, and then update *WHERE
2883 // so that the next one goes after this one.
2884 Sections_elements::iterator p = *where;
2885 gold_assert(p != this->sections_elements_->end());
2887 *where = this->sections_elements_->insert(p, orphan);
2891 os->clear_is_relro();
2892 // We don't have a place to put this orphan section. Put it,
2893 // and all other sections like it, at the end, but before the
2894 // sections which always come at the end.
2895 Sections_elements::iterator last = osp->last_place();
2896 *where = this->sections_elements_->insert(last, orphan);
2900 // Set the addresses of all the output sections. Walk through all the
2901 // elements, tracking the dot symbol. Apply assignments which set
2902 // absolute symbol values, in case they are used when setting dot.
2903 // Fill in data statement values. As we find output sections, set the
2904 // address, set the address of all associated input sections, and
2905 // update dot. Return the segment which should hold the file header
2906 // and segment headers, if any.
2909 Script_sections::set_section_addresses(Symbol_table* symtab, Layout* layout)
2911 gold_assert(this->saw_sections_clause_);
2913 // Implement ONLY_IF_RO/ONLY_IF_RW constraints. These are a pain
2914 // for our representation.
2915 for (Sections_elements::iterator p = this->sections_elements_->begin();
2916 p != this->sections_elements_->end();
2919 Output_section_definition* posd;
2920 Section_constraint failed_constraint = (*p)->check_constraint(&posd);
2921 if (failed_constraint != CONSTRAINT_NONE)
2923 Sections_elements::iterator q;
2924 for (q = this->sections_elements_->begin();
2925 q != this->sections_elements_->end();
2930 if ((*q)->alternate_constraint(posd, failed_constraint))
2935 if (q == this->sections_elements_->end())
2936 gold_error(_("no matching section constraint"));
2940 // Force the alignment of the first TLS section to be the maximum
2941 // alignment of all TLS sections.
2942 Output_section* first_tls = NULL;
2943 uint64_t tls_align = 0;
2944 for (Sections_elements::const_iterator p = this->sections_elements_->begin();
2945 p != this->sections_elements_->end();
2948 Output_section *os = (*p)->get_output_section();
2949 if (os != NULL && (os->flags() & elfcpp::SHF_TLS) != 0)
2951 if (first_tls == NULL)
2953 if (os->addralign() > tls_align)
2954 tls_align = os->addralign();
2957 if (first_tls != NULL)
2958 first_tls->set_addralign(tls_align);
2960 // For a relocatable link, we implicitly set dot to zero.
2961 uint64_t dot_value = 0;
2962 uint64_t dot_alignment = 0;
2963 uint64_t load_address = 0;
2965 // Check to see if we want to use any of -Ttext, -Tdata and -Tbss options
2966 // to set section addresses. If the script has any SEGMENT_START
2967 // expression, we do not set the section addresses.
2968 bool use_tsection_options =
2969 (!this->saw_segment_start_expression_
2970 && (parameters->options().user_set_Ttext()
2971 || parameters->options().user_set_Tdata()
2972 || parameters->options().user_set_Tbss()));
2974 for (Sections_elements::iterator p = this->sections_elements_->begin();
2975 p != this->sections_elements_->end();
2978 Output_section* os = (*p)->get_output_section();
2980 // Handle -Ttext, -Tdata and -Tbss options. We do this by looking for
2981 // the special sections by names and doing dot assignments.
2982 if (use_tsection_options
2984 && (os->flags() & elfcpp::SHF_ALLOC) != 0)
2986 uint64_t new_dot_value = dot_value;
2988 if (parameters->options().user_set_Ttext()
2989 && strcmp(os->name(), ".text") == 0)
2990 new_dot_value = parameters->options().Ttext();
2991 else if (parameters->options().user_set_Tdata()
2992 && strcmp(os->name(), ".data") == 0)
2993 new_dot_value = parameters->options().Tdata();
2994 else if (parameters->options().user_set_Tbss()
2995 && strcmp(os->name(), ".bss") == 0)
2996 new_dot_value = parameters->options().Tbss();
2998 // Update dot and load address if necessary.
2999 if (new_dot_value < dot_value)
3000 gold_error(_("dot may not move backward"));
3001 else if (new_dot_value != dot_value)
3003 dot_value = new_dot_value;
3004 load_address = new_dot_value;
3008 (*p)->set_section_addresses(symtab, layout, &dot_value, &dot_alignment,
3012 if (this->phdrs_elements_ != NULL)
3014 for (Phdrs_elements::iterator p = this->phdrs_elements_->begin();
3015 p != this->phdrs_elements_->end();
3017 (*p)->eval_load_address(symtab, layout);
3020 return this->create_segments(layout, dot_alignment);
3023 // Sort the sections in order to put them into segments.
3025 class Sort_output_sections
3029 operator()(const Output_section* os1, const Output_section* os2) const;
3033 Sort_output_sections::operator()(const Output_section* os1,
3034 const Output_section* os2) const
3036 // Sort first by the load address.
3037 uint64_t lma1 = (os1->has_load_address()
3038 ? os1->load_address()
3040 uint64_t lma2 = (os2->has_load_address()
3041 ? os2->load_address()
3046 // Then sort by the virtual address.
3047 if (os1->address() != os2->address())
3048 return os1->address() < os2->address();
3050 // Sort TLS sections to the end.
3051 bool tls1 = (os1->flags() & elfcpp::SHF_TLS) != 0;
3052 bool tls2 = (os2->flags() & elfcpp::SHF_TLS) != 0;
3056 // Sort PROGBITS before NOBITS.
3057 if (os1->type() == elfcpp::SHT_PROGBITS && os2->type() == elfcpp::SHT_NOBITS)
3059 if (os1->type() == elfcpp::SHT_NOBITS && os2->type() == elfcpp::SHT_PROGBITS)
3062 // Sort non-NOLOAD before NOLOAD.
3063 if (os1->is_noload() && !os2->is_noload())
3065 if (!os1->is_noload() && os2->is_noload())
3068 // Otherwise we don't care.
3072 // Return whether OS is a BSS section. This is a SHT_NOBITS section.
3073 // We treat a section with the SHF_TLS flag set as taking up space
3074 // even if it is SHT_NOBITS (this is true of .tbss), as we allocate
3075 // space for them in the file.
3078 Script_sections::is_bss_section(const Output_section* os)
3080 return (os->type() == elfcpp::SHT_NOBITS
3081 && (os->flags() & elfcpp::SHF_TLS) == 0);
3084 // Return the size taken by the file header and the program headers.
3087 Script_sections::total_header_size(Layout* layout) const
3089 size_t segment_count = layout->segment_count();
3090 size_t file_header_size;
3091 size_t segment_headers_size;
3092 if (parameters->target().get_size() == 32)
3094 file_header_size = elfcpp::Elf_sizes<32>::ehdr_size;
3095 segment_headers_size = segment_count * elfcpp::Elf_sizes<32>::phdr_size;
3097 else if (parameters->target().get_size() == 64)
3099 file_header_size = elfcpp::Elf_sizes<64>::ehdr_size;
3100 segment_headers_size = segment_count * elfcpp::Elf_sizes<64>::phdr_size;
3105 return file_header_size + segment_headers_size;
3108 // Return the amount we have to subtract from the LMA to accomodate
3109 // headers of the given size. The complication is that the file
3110 // header have to be at the start of a page, as otherwise it will not
3111 // be at the start of the file.
3114 Script_sections::header_size_adjustment(uint64_t lma,
3115 size_t sizeof_headers) const
3117 const uint64_t abi_pagesize = parameters->target().abi_pagesize();
3118 uint64_t hdr_lma = lma - sizeof_headers;
3119 hdr_lma &= ~(abi_pagesize - 1);
3120 return lma - hdr_lma;
3123 // Create the PT_LOAD segments when using a SECTIONS clause. Returns
3124 // the segment which should hold the file header and segment headers,
3128 Script_sections::create_segments(Layout* layout, uint64_t dot_alignment)
3130 gold_assert(this->saw_sections_clause_);
3132 if (parameters->options().relocatable())
3135 if (this->saw_phdrs_clause())
3136 return create_segments_from_phdrs_clause(layout, dot_alignment);
3138 Layout::Section_list sections;
3139 layout->get_allocated_sections(§ions);
3141 // Sort the sections by address.
3142 std::stable_sort(sections.begin(), sections.end(), Sort_output_sections());
3144 this->create_note_and_tls_segments(layout, §ions);
3146 // Walk through the sections adding them to PT_LOAD segments.
3147 const uint64_t abi_pagesize = parameters->target().abi_pagesize();
3148 Output_segment* first_seg = NULL;
3149 Output_segment* current_seg = NULL;
3150 bool is_current_seg_readonly = true;
3151 Layout::Section_list::iterator plast = sections.end();
3152 uint64_t last_vma = 0;
3153 uint64_t last_lma = 0;
3154 uint64_t last_size = 0;
3155 for (Layout::Section_list::iterator p = sections.begin();
3156 p != sections.end();
3159 const uint64_t vma = (*p)->address();
3160 const uint64_t lma = ((*p)->has_load_address()
3161 ? (*p)->load_address()
3163 const uint64_t size = (*p)->current_data_size();
3165 bool need_new_segment;
3166 if (current_seg == NULL)
3167 need_new_segment = true;
3168 else if (lma - vma != last_lma - last_vma)
3170 // This section has a different LMA relationship than the
3171 // last one; we need a new segment.
3172 need_new_segment = true;
3174 else if (align_address(last_lma + last_size, abi_pagesize)
3175 < align_address(lma, abi_pagesize))
3177 // Putting this section in the segment would require
3179 need_new_segment = true;
3181 else if (is_bss_section(*plast) && !is_bss_section(*p))
3183 // A non-BSS section can not follow a BSS section in the
3185 need_new_segment = true;
3187 else if (is_current_seg_readonly
3188 && ((*p)->flags() & elfcpp::SHF_WRITE) != 0
3189 && !parameters->options().omagic())
3191 // Don't put a writable section in the same segment as a
3192 // non-writable section.
3193 need_new_segment = true;
3197 // Otherwise, reuse the existing segment.
3198 need_new_segment = false;
3201 elfcpp::Elf_Word seg_flags =
3202 Layout::section_flags_to_segment((*p)->flags());
3204 if (need_new_segment)
3206 current_seg = layout->make_output_segment(elfcpp::PT_LOAD,
3208 current_seg->set_addresses(vma, lma);
3209 current_seg->set_minimum_p_align(dot_alignment);
3210 if (first_seg == NULL)
3211 first_seg = current_seg;
3212 is_current_seg_readonly = true;
3215 current_seg->add_output_section(*p, seg_flags, false);
3217 if (((*p)->flags() & elfcpp::SHF_WRITE) != 0)
3218 is_current_seg_readonly = false;
3226 // An ELF program should work even if the program headers are not in
3227 // a PT_LOAD segment. However, it appears that the Linux kernel
3228 // does not set the AT_PHDR auxiliary entry in that case. It sets
3229 // the load address to p_vaddr - p_offset of the first PT_LOAD
3230 // segment. It then sets AT_PHDR to the load address plus the
3231 // offset to the program headers, e_phoff in the file header. This
3232 // fails when the program headers appear in the file before the
3233 // first PT_LOAD segment. Therefore, we always create a PT_LOAD
3234 // segment to hold the file header and the program headers. This is
3235 // effectively what the GNU linker does, and it is slightly more
3236 // efficient in any case. We try to use the first PT_LOAD segment
3237 // if we can, otherwise we make a new one.
3239 if (first_seg == NULL)
3242 // -n or -N mean that the program is not demand paged and there is
3243 // no need to put the program headers in a PT_LOAD segment.
3244 if (parameters->options().nmagic() || parameters->options().omagic())
3247 size_t sizeof_headers = this->total_header_size(layout);
3249 uint64_t vma = first_seg->vaddr();
3250 uint64_t lma = first_seg->paddr();
3252 uint64_t subtract = this->header_size_adjustment(lma, sizeof_headers);
3254 if ((lma & (abi_pagesize - 1)) >= sizeof_headers)
3256 first_seg->set_addresses(vma - subtract, lma - subtract);
3260 // If there is no room to squeeze in the headers, then punt. The
3261 // resulting executable probably won't run on GNU/Linux, but we
3262 // trust that the user knows what they are doing.
3263 if (lma < subtract || vma < subtract)
3266 Output_segment* load_seg = layout->make_output_segment(elfcpp::PT_LOAD,
3268 load_seg->set_addresses(vma - subtract, lma - subtract);
3273 // Create a PT_NOTE segment for each SHT_NOTE section and a PT_TLS
3274 // segment if there are any SHT_TLS sections.
3277 Script_sections::create_note_and_tls_segments(
3279 const Layout::Section_list* sections)
3281 gold_assert(!this->saw_phdrs_clause());
3283 bool saw_tls = false;
3284 for (Layout::Section_list::const_iterator p = sections->begin();
3285 p != sections->end();
3288 if ((*p)->type() == elfcpp::SHT_NOTE)
3290 elfcpp::Elf_Word seg_flags =
3291 Layout::section_flags_to_segment((*p)->flags());
3292 Output_segment* oseg = layout->make_output_segment(elfcpp::PT_NOTE,
3294 oseg->add_output_section(*p, seg_flags, false);
3296 // Incorporate any subsequent SHT_NOTE sections, in the
3297 // hopes that the script is sensible.
3298 Layout::Section_list::const_iterator pnext = p + 1;
3299 while (pnext != sections->end()
3300 && (*pnext)->type() == elfcpp::SHT_NOTE)
3302 seg_flags = Layout::section_flags_to_segment((*pnext)->flags());
3303 oseg->add_output_section(*pnext, seg_flags, false);
3309 if (((*p)->flags() & elfcpp::SHF_TLS) != 0)
3312 gold_error(_("TLS sections are not adjacent"));
3314 elfcpp::Elf_Word seg_flags =
3315 Layout::section_flags_to_segment((*p)->flags());
3316 Output_segment* oseg = layout->make_output_segment(elfcpp::PT_TLS,
3318 oseg->add_output_section(*p, seg_flags, false);
3320 Layout::Section_list::const_iterator pnext = p + 1;
3321 while (pnext != sections->end()
3322 && ((*pnext)->flags() & elfcpp::SHF_TLS) != 0)
3324 seg_flags = Layout::section_flags_to_segment((*pnext)->flags());
3325 oseg->add_output_section(*pnext, seg_flags, false);
3335 // Add a program header. The PHDRS clause is syntactically distinct
3336 // from the SECTIONS clause, but we implement it with the SECTIONS
3337 // support because PHDRS is useless if there is no SECTIONS clause.
3340 Script_sections::add_phdr(const char* name, size_t namelen, unsigned int type,
3341 bool includes_filehdr, bool includes_phdrs,
3342 bool is_flags_valid, unsigned int flags,
3343 Expression* load_address)
3345 if (this->phdrs_elements_ == NULL)
3346 this->phdrs_elements_ = new Phdrs_elements();
3347 this->phdrs_elements_->push_back(new Phdrs_element(name, namelen, type,
3350 is_flags_valid, flags,
3354 // Return the number of segments we expect to create based on the
3355 // SECTIONS clause. This is used to implement SIZEOF_HEADERS.
3358 Script_sections::expected_segment_count(const Layout* layout) const
3360 if (this->saw_phdrs_clause())
3361 return this->phdrs_elements_->size();
3363 Layout::Section_list sections;
3364 layout->get_allocated_sections(§ions);
3366 // We assume that we will need two PT_LOAD segments.
3369 bool saw_note = false;
3370 bool saw_tls = false;
3371 for (Layout::Section_list::const_iterator p = sections.begin();
3372 p != sections.end();
3375 if ((*p)->type() == elfcpp::SHT_NOTE)
3377 // Assume that all note sections will fit into a single
3385 else if (((*p)->flags() & elfcpp::SHF_TLS) != 0)
3387 // There can only be one PT_TLS segment.
3399 // Create the segments from a PHDRS clause. Return the segment which
3400 // should hold the file header and program headers, if any.
3403 Script_sections::create_segments_from_phdrs_clause(Layout* layout,
3404 uint64_t dot_alignment)
3406 this->attach_sections_using_phdrs_clause(layout);
3407 return this->set_phdrs_clause_addresses(layout, dot_alignment);
3410 // Create the segments from the PHDRS clause, and put the output
3411 // sections in them.
3414 Script_sections::attach_sections_using_phdrs_clause(Layout* layout)
3416 typedef std::map<std::string, Output_segment*> Name_to_segment;
3417 Name_to_segment name_to_segment;
3418 for (Phdrs_elements::const_iterator p = this->phdrs_elements_->begin();
3419 p != this->phdrs_elements_->end();
3421 name_to_segment[(*p)->name()] = (*p)->create_segment(layout);
3423 // Walk through the output sections and attach them to segments.
3424 // Output sections in the script which do not list segments are
3425 // attached to the same set of segments as the immediately preceding
3428 String_list* phdr_names = NULL;
3429 bool load_segments_only = false;
3430 for (Sections_elements::const_iterator p = this->sections_elements_->begin();
3431 p != this->sections_elements_->end();
3435 String_list* old_phdr_names = phdr_names;
3436 Output_section* os = (*p)->allocate_to_segment(&phdr_names, &orphan);
3440 if (phdr_names == NULL)
3442 gold_error(_("allocated section not in any segment"));
3446 // We see a list of segments names. Disable PT_LOAD segment only
3448 if (old_phdr_names != phdr_names)
3449 load_segments_only = false;
3451 // If this is an orphan section--one that was not explicitly
3452 // mentioned in the linker script--then it should not inherit
3453 // any segment type other than PT_LOAD. Otherwise, e.g., the
3454 // PT_INTERP segment will pick up following orphan sections,
3455 // which does not make sense. If this is not an orphan section,
3456 // we trust the linker script.
3459 // Enable PT_LOAD segments only filtering until we see another
3460 // list of segment names.
3461 load_segments_only = true;
3464 bool in_load_segment = false;
3465 for (String_list::const_iterator q = phdr_names->begin();
3466 q != phdr_names->end();
3469 Name_to_segment::const_iterator r = name_to_segment.find(*q);
3470 if (r == name_to_segment.end())
3471 gold_error(_("no segment %s"), q->c_str());
3474 if (load_segments_only
3475 && r->second->type() != elfcpp::PT_LOAD)
3478 elfcpp::Elf_Word seg_flags =
3479 Layout::section_flags_to_segment(os->flags());
3480 r->second->add_output_section(os, seg_flags, false);
3482 if (r->second->type() == elfcpp::PT_LOAD)
3484 if (in_load_segment)
3485 gold_error(_("section in two PT_LOAD segments"));
3486 in_load_segment = true;
3491 if (!in_load_segment)
3492 gold_error(_("allocated section not in any PT_LOAD segment"));
3496 // Set the addresses for segments created from a PHDRS clause. Return
3497 // the segment which should hold the file header and program headers,
3501 Script_sections::set_phdrs_clause_addresses(Layout* layout,
3502 uint64_t dot_alignment)
3504 Output_segment* load_seg = NULL;
3505 for (Phdrs_elements::const_iterator p = this->phdrs_elements_->begin();
3506 p != this->phdrs_elements_->end();
3509 // Note that we have to set the flags after adding the output
3510 // sections to the segment, as adding an output segment can
3511 // change the flags.
3512 (*p)->set_flags_if_valid();
3514 Output_segment* oseg = (*p)->segment();
3516 if (oseg->type() != elfcpp::PT_LOAD)
3518 // The addresses of non-PT_LOAD segments are set from the
3519 // PT_LOAD segments.
3520 if ((*p)->has_load_address())
3521 gold_error(_("may only specify load address for PT_LOAD segment"));
3525 oseg->set_minimum_p_align(dot_alignment);
3527 // The output sections should have addresses from the SECTIONS
3528 // clause. The addresses don't have to be in order, so find the
3529 // one with the lowest load address. Use that to set the
3530 // address of the segment.
3532 Output_section* osec = oseg->section_with_lowest_load_address();
3535 oseg->set_addresses(0, 0);
3539 uint64_t vma = osec->address();
3540 uint64_t lma = osec->has_load_address() ? osec->load_address() : vma;
3542 // Override the load address of the section with the load
3543 // address specified for the segment.
3544 if ((*p)->has_load_address())
3546 if (osec->has_load_address())
3547 gold_warning(_("PHDRS load address overrides "
3548 "section %s load address"),
3551 lma = (*p)->load_address();
3554 bool headers = (*p)->includes_filehdr() && (*p)->includes_phdrs();
3555 if (!headers && ((*p)->includes_filehdr() || (*p)->includes_phdrs()))
3557 // We could support this if we wanted to.
3558 gold_error(_("using only one of FILEHDR and PHDRS is "
3559 "not currently supported"));
3563 size_t sizeof_headers = this->total_header_size(layout);
3564 uint64_t subtract = this->header_size_adjustment(lma,
3566 if (lma >= subtract && vma >= subtract)
3573 gold_error(_("sections loaded on first page without room "
3574 "for file and program headers "
3575 "are not supported"));
3578 if (load_seg != NULL)
3579 gold_error(_("using FILEHDR and PHDRS on more than one "
3580 "PT_LOAD segment is not currently supported"));
3584 oseg->set_addresses(vma, lma);
3590 // Add the file header and segment headers to non-load segments
3591 // specified in the PHDRS clause.
3594 Script_sections::put_headers_in_phdrs(Output_data* file_header,
3595 Output_data* segment_headers)
3597 gold_assert(this->saw_phdrs_clause());
3598 for (Phdrs_elements::iterator p = this->phdrs_elements_->begin();
3599 p != this->phdrs_elements_->end();
3602 if ((*p)->type() != elfcpp::PT_LOAD)
3604 if ((*p)->includes_phdrs())
3605 (*p)->segment()->add_initial_output_data(segment_headers);
3606 if ((*p)->includes_filehdr())
3607 (*p)->segment()->add_initial_output_data(file_header);
3612 // Look for an output section by name and return the address, the load
3613 // address, the alignment, and the size. This is used when an
3614 // expression refers to an output section which was not actually
3615 // created. This returns true if the section was found, false
3619 Script_sections::get_output_section_info(const char* name, uint64_t* address,
3620 uint64_t* load_address,
3621 uint64_t* addralign,
3622 uint64_t* size) const
3624 if (!this->saw_sections_clause_)
3626 for (Sections_elements::const_iterator p = this->sections_elements_->begin();
3627 p != this->sections_elements_->end();
3629 if ((*p)->get_output_section_info(name, address, load_address, addralign,
3635 // Release all Output_segments. This remove all pointers to all
3639 Script_sections::release_segments()
3641 if (this->saw_phdrs_clause())
3643 for (Phdrs_elements::const_iterator p = this->phdrs_elements_->begin();
3644 p != this->phdrs_elements_->end();
3646 (*p)->release_segment();
3650 // Print the SECTIONS clause to F for debugging.
3653 Script_sections::print(FILE* f) const
3655 if (!this->saw_sections_clause_)
3658 fprintf(f, "SECTIONS {\n");
3660 for (Sections_elements::const_iterator p = this->sections_elements_->begin();
3661 p != this->sections_elements_->end();
3667 if (this->phdrs_elements_ != NULL)
3669 fprintf(f, "PHDRS {\n");
3670 for (Phdrs_elements::const_iterator p = this->phdrs_elements_->begin();
3671 p != this->phdrs_elements_->end();
3678 } // End namespace gold.