1 // script-sections.cc -- linker script SECTIONS for gold
3 // Copyright (C) 2008-2016 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 // A region of memory.
50 Memory_region(const char* name, size_t namelen, unsigned int attributes,
51 Expression* start, Expression* length)
52 : name_(name, namelen),
53 attributes_(attributes),
62 // Return the name of this region.
65 { return this->name_; }
67 // Return the start address of this region.
70 { return this->start_; }
72 // Return the length of this region.
75 { return this->length_; }
77 // Print the region (when debugging).
81 // Return true if <name,namelen> matches this region.
83 name_match(const char* name, size_t namelen)
85 return (this->name_.length() == namelen
86 && strncmp(this->name_.c_str(), name, namelen) == 0);
90 get_current_address() const
93 script_exp_binary_add(this->start_,
94 script_exp_integer(this->current_offset_));
98 set_address(uint64_t addr, const Symbol_table* symtab, const Layout* layout)
100 uint64_t start = this->start_->eval(symtab, layout, false);
101 uint64_t len = this->length_->eval(symtab, layout, false);
102 if (addr < start || addr >= start + len)
103 gold_error(_("address 0x%llx is not within region %s"),
104 static_cast<unsigned long long>(addr),
105 this->name_.c_str());
106 else if (addr < start + this->current_offset_)
107 gold_error(_("address 0x%llx moves dot backwards in region %s"),
108 static_cast<unsigned long long>(addr),
109 this->name_.c_str());
110 this->current_offset_ = addr - start;
114 increment_offset(std::string section_name, uint64_t amount,
115 const Symbol_table* symtab, const Layout* layout)
117 this->current_offset_ += amount;
119 if (this->current_offset_
120 > this->length_->eval(symtab, layout, false))
121 gold_error(_("section %s overflows end of region %s"),
122 section_name.c_str(), this->name_.c_str());
125 // Returns true iff there is room left in this region
126 // for AMOUNT more bytes of data.
128 has_room_for(const Symbol_table* symtab, const Layout* layout,
129 uint64_t amount) const
131 return (this->current_offset_ + amount
132 < this->length_->eval(symtab, layout, false));
135 // Return true if the provided section flags
136 // are compatible with this region's attributes.
138 attributes_compatible(elfcpp::Elf_Xword flags, elfcpp::Elf_Xword type) const;
141 add_section(Output_section_definition* sec, bool vma)
144 this->vma_sections_.push_back(sec);
146 this->lma_sections_.push_back(sec);
149 typedef std::vector<Output_section_definition*> Section_list;
151 // Return the start of the list of sections
152 // whose VMAs are taken from this region.
153 Section_list::const_iterator
154 get_vma_section_list_start() const
155 { return this->vma_sections_.begin(); }
157 // Return the start of the list of sections
158 // whose LMAs are taken from this region.
159 Section_list::const_iterator
160 get_lma_section_list_start() const
161 { return this->lma_sections_.begin(); }
163 // Return the end of the list of sections
164 // whose VMAs are taken from this region.
165 Section_list::const_iterator
166 get_vma_section_list_end() const
167 { return this->vma_sections_.end(); }
169 // Return the end of the list of sections
170 // whose LMAs are taken from this region.
171 Section_list::const_iterator
172 get_lma_section_list_end() const
173 { return this->lma_sections_.end(); }
175 Output_section_definition*
176 get_last_section() const
177 { return this->last_section_; }
180 set_last_section(Output_section_definition* sec)
181 { this->last_section_ = sec; }
186 unsigned int attributes_;
189 // The offset to the next free byte in the region.
190 // Note - for compatibility with GNU LD we only maintain one offset
191 // regardless of whether the region is being used for VMA values,
192 // LMA values, or both.
193 uint64_t current_offset_;
194 // A list of sections whose VMAs are set inside this region.
195 Section_list vma_sections_;
196 // A list of sections whose LMAs are set inside this region.
197 Section_list lma_sections_;
198 // The latest section to make use of this region.
199 Output_section_definition* last_section_;
202 // Return true if the provided section flags
203 // are compatible with this region's attributes.
206 Memory_region::attributes_compatible(elfcpp::Elf_Xword flags,
207 elfcpp::Elf_Xword type) const
209 unsigned int attrs = this->attributes_;
211 // No attributes means that this region is not compatible with anything.
218 switch (attrs & - attrs)
221 if ((flags & elfcpp::SHF_EXECINSTR) == 0)
226 if ((flags & elfcpp::SHF_WRITE) == 0)
231 // All sections are presumed readable.
234 case MEM_ALLOCATABLE:
235 if ((flags & elfcpp::SHF_ALLOC) == 0)
239 case MEM_INITIALIZED:
240 if ((type & elfcpp::SHT_NOBITS) != 0)
244 attrs &= ~ (attrs & - attrs);
251 // Print a memory region.
254 Memory_region::print(FILE* f) const
256 fprintf(f, " %s", this->name_.c_str());
258 unsigned int attrs = this->attributes_;
264 switch (attrs & - attrs)
266 case MEM_EXECUTABLE: fputc('x', f); break;
267 case MEM_WRITEABLE: fputc('w', f); break;
268 case MEM_READABLE: fputc('r', f); break;
269 case MEM_ALLOCATABLE: fputc('a', f); break;
270 case MEM_INITIALIZED: fputc('i', f); break;
274 attrs &= ~ (attrs & - attrs);
280 fprintf(f, " : origin = ");
281 this->start_->print(f);
282 fprintf(f, ", length = ");
283 this->length_->print(f);
287 // Manage orphan sections. This is intended to be largely compatible
288 // with the GNU linker. The Linux kernel implicitly relies on
289 // something similar to the GNU linker's orphan placement. We
290 // originally used a simpler scheme here, but it caused the kernel
291 // build to fail, and was also rather inefficient.
293 class Orphan_section_placement
296 typedef Script_sections::Elements_iterator Elements_iterator;
299 Orphan_section_placement();
301 // Handle an output section during initialization of this mapping.
303 output_section_init(const std::string& name, Output_section*,
304 Elements_iterator location);
306 // Initialize the last location.
308 last_init(Elements_iterator location);
310 // Set *PWHERE to the address of an iterator pointing to the
311 // location to use for an orphan section. Return true if the
312 // iterator has a value, false otherwise.
314 find_place(Output_section*, Elements_iterator** pwhere);
316 // Update PLACE_LAST_ALLOC.
318 update_last_alloc(Elements_iterator where);
320 // Return the iterator being used for sections at the very end of
321 // the linker script.
326 // The places that we specifically recognize. This list is copied
327 // from the GNU linker.
344 // The information we keep for a specific place.
347 // The name of sections for this place.
349 // Whether we have a location for this place.
351 // The iterator for this place.
352 Elements_iterator location;
355 // Initialize one place element.
357 initialize_place(Place_index, const char*);
360 Place places_[PLACE_MAX];
361 // True if this is the first call to output_section_init.
365 // Initialize Orphan_section_placement.
367 Orphan_section_placement::Orphan_section_placement()
370 this->initialize_place(PLACE_TEXT, ".text");
371 this->initialize_place(PLACE_RODATA, ".rodata");
372 this->initialize_place(PLACE_DATA, ".data");
373 this->initialize_place(PLACE_TLS, NULL);
374 this->initialize_place(PLACE_TLS_BSS, NULL);
375 this->initialize_place(PLACE_BSS, ".bss");
376 this->initialize_place(PLACE_LAST_ALLOC, NULL);
377 this->initialize_place(PLACE_REL, NULL);
378 this->initialize_place(PLACE_INTERP, ".interp");
379 this->initialize_place(PLACE_NONALLOC, NULL);
380 this->initialize_place(PLACE_LAST, NULL);
383 // Initialize one place element.
386 Orphan_section_placement::initialize_place(Place_index index, const char* name)
388 this->places_[index].name = name;
389 this->places_[index].have_location = false;
392 // While initializing the Orphan_section_placement information, this
393 // is called once for each output section named in the linker script.
394 // If we found an output section during the link, it will be passed in
398 Orphan_section_placement::output_section_init(const std::string& name,
400 Elements_iterator location)
402 bool first_init = this->first_init_;
403 this->first_init_ = false;
405 // Remember the last allocated section. Any orphan bss sections
406 // will be placed after it.
408 && (os->flags() & elfcpp::SHF_ALLOC) != 0)
410 this->places_[PLACE_LAST_ALLOC].location = location;
411 this->places_[PLACE_LAST_ALLOC].have_location = true;
414 for (int i = 0; i < PLACE_MAX; ++i)
416 if (this->places_[i].name != NULL && this->places_[i].name == name)
418 if (this->places_[i].have_location)
420 // We have already seen a section with this name.
424 this->places_[i].location = location;
425 this->places_[i].have_location = true;
427 // If we just found the .bss section, restart the search for
428 // an unallocated section. This follows the GNU linker's
431 this->places_[PLACE_NONALLOC].have_location = false;
437 // Relocation sections.
438 if (!this->places_[PLACE_REL].have_location
440 && (os->type() == elfcpp::SHT_REL || os->type() == elfcpp::SHT_RELA)
441 && (os->flags() & elfcpp::SHF_ALLOC) != 0)
443 this->places_[PLACE_REL].location = location;
444 this->places_[PLACE_REL].have_location = true;
447 // We find the location for unallocated sections by finding the
448 // first debugging or comment section after the BSS section (if
450 if (!this->places_[PLACE_NONALLOC].have_location
451 && (name == ".comment" || Layout::is_debug_info_section(name.c_str())))
453 // We add orphan sections after the location in PLACES_. We
454 // want to store unallocated sections before LOCATION. If this
455 // is the very first section, we can't use it.
459 this->places_[PLACE_NONALLOC].location = location;
460 this->places_[PLACE_NONALLOC].have_location = true;
465 // Initialize the last location.
468 Orphan_section_placement::last_init(Elements_iterator location)
470 this->places_[PLACE_LAST].location = location;
471 this->places_[PLACE_LAST].have_location = true;
474 // Set *PWHERE to the address of an iterator pointing to the location
475 // to use for an orphan section. Return true if the iterator has a
476 // value, false otherwise.
479 Orphan_section_placement::find_place(Output_section* os,
480 Elements_iterator** pwhere)
482 // Figure out where OS should go. This is based on the GNU linker
483 // code. FIXME: The GNU linker handles small data sections
484 // specially, but we don't.
485 elfcpp::Elf_Word type = os->type();
486 elfcpp::Elf_Xword flags = os->flags();
488 if ((flags & elfcpp::SHF_ALLOC) == 0
489 && !Layout::is_debug_info_section(os->name()))
490 index = PLACE_NONALLOC;
491 else if ((flags & elfcpp::SHF_ALLOC) == 0)
493 else if (type == elfcpp::SHT_NOTE)
494 index = PLACE_INTERP;
495 else if ((flags & elfcpp::SHF_TLS) != 0)
497 if (type == elfcpp::SHT_NOBITS)
498 index = PLACE_TLS_BSS;
502 else if (type == elfcpp::SHT_NOBITS)
504 else if ((flags & elfcpp::SHF_WRITE) != 0)
506 else if (type == elfcpp::SHT_REL || type == elfcpp::SHT_RELA)
508 else if ((flags & elfcpp::SHF_EXECINSTR) == 0)
509 index = PLACE_RODATA;
513 // If we don't have a location yet, try to find one based on a
514 // plausible ordering of sections.
515 if (!this->places_[index].have_location)
527 follow = PLACE_RODATA;
528 if (!this->places_[PLACE_RODATA].have_location)
532 follow = PLACE_LAST_ALLOC;
545 if (!this->places_[PLACE_TLS].have_location)
549 if (follow != PLACE_MAX && this->places_[follow].have_location)
551 // Set the location of INDEX to the location of FOLLOW. The
552 // location of INDEX will then be incremented by the caller,
553 // so anything in INDEX will continue to be after anything
555 this->places_[index].location = this->places_[follow].location;
556 this->places_[index].have_location = true;
560 *pwhere = &this->places_[index].location;
561 bool ret = this->places_[index].have_location;
563 // The caller will set the location.
564 this->places_[index].have_location = true;
569 // Update PLACE_LAST_ALLOC.
571 Orphan_section_placement::update_last_alloc(Elements_iterator elem)
573 Elements_iterator prev = elem;
575 if (this->places_[PLACE_LAST_ALLOC].have_location
576 && this->places_[PLACE_LAST_ALLOC].location == prev)
578 this->places_[PLACE_LAST_ALLOC].have_location = true;
579 this->places_[PLACE_LAST_ALLOC].location = elem;
583 // Return the iterator being used for sections at the very end of the
586 Orphan_section_placement::Elements_iterator
587 Orphan_section_placement::last_place() const
589 gold_assert(this->places_[PLACE_LAST].have_location);
590 return this->places_[PLACE_LAST].location;
593 // An element in a SECTIONS clause.
595 class Sections_element
601 virtual ~Sections_element()
604 // Return whether an output section is relro.
609 // Record that an output section is relro.
614 // Create any required output sections. The only real
615 // implementation is in Output_section_definition.
617 create_sections(Layout*)
620 // Add any symbol being defined to the symbol table.
622 add_symbols_to_table(Symbol_table*)
625 // Finalize symbols and check assertions.
627 finalize_symbols(Symbol_table*, const Layout*, uint64_t*)
630 // Return the output section name to use for an input file name and
631 // section name. This only real implementation is in
632 // Output_section_definition.
634 output_section_name(const char*, const char*, Output_section***,
635 Script_sections::Section_type*, bool*)
638 // Initialize OSP with an output section.
640 orphan_section_init(Orphan_section_placement*,
641 Script_sections::Elements_iterator)
644 // Set section addresses. This includes applying assignments if the
645 // expression is an absolute value.
647 set_section_addresses(Symbol_table*, Layout*, uint64_t*, uint64_t*,
651 // Check a constraint (ONLY_IF_RO, etc.) on an output section. If
652 // this section is constrained, and the input sections do not match,
653 // return the constraint, and set *POSD.
654 virtual Section_constraint
655 check_constraint(Output_section_definition**)
656 { return CONSTRAINT_NONE; }
658 // See if this is the alternate output section for a constrained
659 // output section. If it is, transfer the Output_section and return
660 // true. Otherwise return false.
662 alternate_constraint(Output_section_definition*, Section_constraint)
665 // Get the list of segments to use for an allocated section when
666 // using a PHDRS clause. If this is an allocated section, return
667 // the Output_section, and set *PHDRS_LIST (the first parameter) to
668 // the list of PHDRS to which it should be attached. If the PHDRS
669 // were not specified, don't change *PHDRS_LIST. When not returning
670 // NULL, set *ORPHAN (the second parameter) according to whether
671 // this is an orphan section--one that is not mentioned in the
673 virtual Output_section*
674 allocate_to_segment(String_list**, bool*)
677 // Look for an output section by name and return the address, the
678 // load address, the alignment, and the size. This is used when an
679 // expression refers to an output section which was not actually
680 // created. This returns true if the section was found, false
681 // otherwise. The only real definition is for
682 // Output_section_definition.
684 get_output_section_info(const char*, uint64_t*, uint64_t*, uint64_t*,
688 // Return the associated Output_section if there is one.
689 virtual Output_section*
690 get_output_section() const
693 // Set the section's memory regions.
695 set_memory_region(Memory_region*, bool)
696 { gold_error(_("Attempt to set a memory region for a non-output section")); }
698 // Print the element for debugging purposes.
700 print(FILE* f) const = 0;
703 // An assignment in a SECTIONS clause outside of an output section.
705 class Sections_element_assignment : public Sections_element
708 Sections_element_assignment(const char* name, size_t namelen,
709 Expression* val, bool provide, bool hidden)
710 : assignment_(name, namelen, false, val, provide, hidden)
713 // Add the symbol to the symbol table.
715 add_symbols_to_table(Symbol_table* symtab)
716 { this->assignment_.add_to_table(symtab); }
718 // Finalize the symbol.
720 finalize_symbols(Symbol_table* symtab, const Layout* layout,
723 this->assignment_.finalize_with_dot(symtab, layout, *dot_value, NULL);
726 // Set the section address. There is no section here, but if the
727 // value is absolute, we set the symbol. This permits us to use
728 // absolute symbols when setting dot.
730 set_section_addresses(Symbol_table* symtab, Layout* layout,
731 uint64_t* dot_value, uint64_t*, uint64_t*)
733 this->assignment_.set_if_absolute(symtab, layout, true, *dot_value, NULL);
736 // Print for debugging.
741 this->assignment_.print(f);
745 Symbol_assignment assignment_;
748 // An assignment to the dot symbol in a SECTIONS clause outside of an
751 class Sections_element_dot_assignment : public Sections_element
754 Sections_element_dot_assignment(Expression* val)
758 // Finalize the symbol.
760 finalize_symbols(Symbol_table* symtab, const Layout* layout,
763 // We ignore the section of the result because outside of an
764 // output section definition the dot symbol is always considered
766 *dot_value = this->val_->eval_with_dot(symtab, layout, true, *dot_value,
767 NULL, NULL, NULL, false);
770 // Update the dot symbol while setting section addresses.
772 set_section_addresses(Symbol_table* symtab, Layout* layout,
773 uint64_t* dot_value, uint64_t* dot_alignment,
774 uint64_t* load_address)
776 *dot_value = this->val_->eval_with_dot(symtab, layout, false, *dot_value,
777 NULL, NULL, dot_alignment, false);
778 *load_address = *dot_value;
781 // Print for debugging.
786 this->val_->print(f);
794 // An assertion in a SECTIONS clause outside of an output section.
796 class Sections_element_assertion : public Sections_element
799 Sections_element_assertion(Expression* check, const char* message,
801 : assertion_(check, message, messagelen)
804 // Check the assertion.
806 finalize_symbols(Symbol_table* symtab, const Layout* layout, uint64_t*)
807 { this->assertion_.check(symtab, layout); }
809 // Print for debugging.
814 this->assertion_.print(f);
818 Script_assertion assertion_;
821 // An element in an output section in a SECTIONS clause.
823 class Output_section_element
826 // A list of input sections.
827 typedef std::list<Output_section::Input_section> Input_section_list;
829 Output_section_element()
832 virtual ~Output_section_element()
835 // Return whether this element requires an output section to exist.
837 needs_output_section() const
840 // Add any symbol being defined to the symbol table.
842 add_symbols_to_table(Symbol_table*)
845 // Finalize symbols and check assertions.
847 finalize_symbols(Symbol_table*, const Layout*, uint64_t*, Output_section**)
850 // Return whether this element matches FILE_NAME and SECTION_NAME.
851 // The only real implementation is in Output_section_element_input.
853 match_name(const char*, const char*, bool *) const
856 // Set section addresses. This includes applying assignments if the
857 // expression is an absolute value.
859 set_section_addresses(Symbol_table*, Layout*, Output_section*, uint64_t,
860 uint64_t*, uint64_t*, Output_section**, std::string*,
864 // Print the element for debugging purposes.
866 print(FILE* f) const = 0;
869 // Return a fill string that is LENGTH bytes long, filling it with
872 get_fill_string(const std::string* fill, section_size_type length) const;
876 Output_section_element::get_fill_string(const std::string* fill,
877 section_size_type length) const
879 std::string this_fill;
880 this_fill.reserve(length);
881 while (this_fill.length() + fill->length() <= length)
883 if (this_fill.length() < length)
884 this_fill.append(*fill, 0, length - this_fill.length());
888 // A symbol assignment in an output section.
890 class Output_section_element_assignment : public Output_section_element
893 Output_section_element_assignment(const char* name, size_t namelen,
894 Expression* val, bool provide,
896 : assignment_(name, namelen, false, val, provide, hidden)
899 // Add the symbol to the symbol table.
901 add_symbols_to_table(Symbol_table* symtab)
902 { this->assignment_.add_to_table(symtab); }
904 // Finalize the symbol.
906 finalize_symbols(Symbol_table* symtab, const Layout* layout,
907 uint64_t* dot_value, Output_section** dot_section)
909 this->assignment_.finalize_with_dot(symtab, layout, *dot_value,
913 // Set the section address. There is no section here, but if the
914 // value is absolute, we set the symbol. This permits us to use
915 // absolute symbols when setting dot.
917 set_section_addresses(Symbol_table* symtab, Layout* layout, Output_section*,
918 uint64_t, uint64_t* dot_value, uint64_t*,
919 Output_section** dot_section, std::string*,
922 this->assignment_.set_if_absolute(symtab, layout, true, *dot_value,
926 // Print for debugging.
931 this->assignment_.print(f);
935 Symbol_assignment assignment_;
938 // An assignment to the dot symbol in an output section.
940 class Output_section_element_dot_assignment : public Output_section_element
943 Output_section_element_dot_assignment(Expression* val)
947 // An assignment to dot within an output section is enough to force
948 // the output section to exist.
950 needs_output_section() const
953 // Finalize the symbol.
955 finalize_symbols(Symbol_table* symtab, const Layout* layout,
956 uint64_t* dot_value, Output_section** dot_section)
958 *dot_value = this->val_->eval_with_dot(symtab, layout, true, *dot_value,
959 *dot_section, dot_section, NULL,
963 // Update the dot symbol while setting section addresses.
965 set_section_addresses(Symbol_table* symtab, Layout* layout, Output_section*,
966 uint64_t, uint64_t* dot_value, uint64_t*,
967 Output_section** dot_section, std::string*,
968 Input_section_list*);
970 // Print for debugging.
975 this->val_->print(f);
983 // Update the dot symbol while setting section addresses.
986 Output_section_element_dot_assignment::set_section_addresses(
987 Symbol_table* symtab,
989 Output_section* output_section,
992 uint64_t* dot_alignment,
993 Output_section** dot_section,
997 uint64_t next_dot = this->val_->eval_with_dot(symtab, layout, false,
998 *dot_value, *dot_section,
999 dot_section, dot_alignment,
1001 if (next_dot < *dot_value)
1002 gold_error(_("dot may not move backward"));
1003 if (next_dot > *dot_value && output_section != NULL)
1005 section_size_type length = convert_to_section_size_type(next_dot
1007 Output_section_data* posd;
1009 posd = new Output_data_zero_fill(length, 0);
1012 std::string this_fill = this->get_fill_string(fill, length);
1013 posd = new Output_data_const(this_fill, 0);
1015 output_section->add_output_section_data(posd);
1016 layout->new_output_section_data_from_script(posd);
1018 *dot_value = next_dot;
1021 // An assertion in an output section.
1023 class Output_section_element_assertion : public Output_section_element
1026 Output_section_element_assertion(Expression* check, const char* message,
1028 : assertion_(check, message, messagelen)
1032 print(FILE* f) const
1035 this->assertion_.print(f);
1039 Script_assertion assertion_;
1042 // We use a special instance of Output_section_data to handle BYTE,
1043 // SHORT, etc. This permits forward references to symbols in the
1046 class Output_data_expression : public Output_section_data
1049 Output_data_expression(int size, bool is_signed, Expression* val,
1050 const Symbol_table* symtab, const Layout* layout,
1051 uint64_t dot_value, Output_section* dot_section)
1052 : Output_section_data(size, 0, true),
1053 is_signed_(is_signed), val_(val), symtab_(symtab),
1054 layout_(layout), dot_value_(dot_value), dot_section_(dot_section)
1058 // Write the data to the output file.
1060 do_write(Output_file*);
1062 // Write the data to a buffer.
1064 do_write_to_buffer(unsigned char*);
1066 // Write to a map file.
1068 do_print_to_mapfile(Mapfile* mapfile) const
1069 { mapfile->print_output_data(this, _("** expression")); }
1072 template<bool big_endian>
1074 endian_write_to_buffer(uint64_t, unsigned char*);
1078 const Symbol_table* symtab_;
1079 const Layout* layout_;
1080 uint64_t dot_value_;
1081 Output_section* dot_section_;
1084 // Write the data element to the output file.
1087 Output_data_expression::do_write(Output_file* of)
1089 unsigned char* view = of->get_output_view(this->offset(), this->data_size());
1090 this->write_to_buffer(view);
1091 of->write_output_view(this->offset(), this->data_size(), view);
1094 // Write the data element to a buffer.
1097 Output_data_expression::do_write_to_buffer(unsigned char* buf)
1099 uint64_t val = this->val_->eval_with_dot(this->symtab_, this->layout_,
1100 true, this->dot_value_,
1101 this->dot_section_, NULL, NULL,
1104 if (parameters->target().is_big_endian())
1105 this->endian_write_to_buffer<true>(val, buf);
1107 this->endian_write_to_buffer<false>(val, buf);
1110 template<bool big_endian>
1112 Output_data_expression::endian_write_to_buffer(uint64_t val,
1115 switch (this->data_size())
1118 elfcpp::Swap_unaligned<8, big_endian>::writeval(buf, val);
1121 elfcpp::Swap_unaligned<16, big_endian>::writeval(buf, val);
1124 elfcpp::Swap_unaligned<32, big_endian>::writeval(buf, val);
1127 if (parameters->target().get_size() == 32)
1130 if (this->is_signed_ && (val & 0x80000000) != 0)
1131 val |= 0xffffffff00000000LL;
1133 elfcpp::Swap_unaligned<64, big_endian>::writeval(buf, val);
1140 // A data item in an output section.
1142 class Output_section_element_data : public Output_section_element
1145 Output_section_element_data(int size, bool is_signed, Expression* val)
1146 : size_(size), is_signed_(is_signed), val_(val)
1149 // If there is a data item, then we must create an output section.
1151 needs_output_section() const
1154 // Finalize symbols--we just need to update dot.
1156 finalize_symbols(Symbol_table*, const Layout*, uint64_t* dot_value,
1158 { *dot_value += this->size_; }
1160 // Store the value in the section.
1162 set_section_addresses(Symbol_table*, Layout*, Output_section*, uint64_t,
1163 uint64_t* dot_value, uint64_t*, Output_section**,
1164 std::string*, Input_section_list*);
1166 // Print for debugging.
1171 // The size in bytes.
1173 // Whether the value is signed.
1179 // Store the value in the section.
1182 Output_section_element_data::set_section_addresses(
1183 Symbol_table* symtab,
1187 uint64_t* dot_value,
1189 Output_section** dot_section,
1191 Input_section_list*)
1193 gold_assert(os != NULL);
1194 Output_data_expression* expression =
1195 new Output_data_expression(this->size_, this->is_signed_, this->val_,
1196 symtab, layout, *dot_value, *dot_section);
1197 os->add_output_section_data(expression);
1198 layout->new_output_section_data_from_script(expression);
1199 *dot_value += this->size_;
1202 // Print for debugging.
1205 Output_section_element_data::print(FILE* f) const
1208 switch (this->size_)
1220 if (this->is_signed_)
1228 fprintf(f, " %s(", s);
1229 this->val_->print(f);
1233 // A fill value setting in an output section.
1235 class Output_section_element_fill : public Output_section_element
1238 Output_section_element_fill(Expression* val)
1242 // Update the fill value while setting section addresses.
1244 set_section_addresses(Symbol_table* symtab, Layout* layout, Output_section*,
1245 uint64_t, uint64_t* dot_value, uint64_t*,
1246 Output_section** dot_section,
1247 std::string* fill, Input_section_list*)
1249 Output_section* fill_section;
1250 uint64_t fill_val = this->val_->eval_with_dot(symtab, layout, false,
1251 *dot_value, *dot_section,
1252 &fill_section, NULL, false);
1253 if (fill_section != NULL)
1254 gold_warning(_("fill value is not absolute"));
1255 // FIXME: The GNU linker supports fill values of arbitrary length.
1256 unsigned char fill_buff[4];
1257 elfcpp::Swap_unaligned<32, true>::writeval(fill_buff, fill_val);
1258 fill->assign(reinterpret_cast<char*>(fill_buff), 4);
1261 // Print for debugging.
1263 print(FILE* f) const
1265 fprintf(f, " FILL(");
1266 this->val_->print(f);
1271 // The new fill value.
1275 // An input section specification in an output section
1277 class Output_section_element_input : public Output_section_element
1280 Output_section_element_input(const Input_section_spec* spec, bool keep);
1282 // Finalize symbols--just update the value of the dot symbol.
1284 finalize_symbols(Symbol_table*, const Layout*, uint64_t* dot_value,
1285 Output_section** dot_section)
1287 *dot_value = this->final_dot_value_;
1288 *dot_section = this->final_dot_section_;
1291 // See whether we match FILE_NAME and SECTION_NAME as an input section.
1292 // If we do then also indicate whether the section should be KEPT.
1294 match_name(const char* file_name, const char* section_name, bool* keep) const;
1296 // Set the section address.
1298 set_section_addresses(Symbol_table* symtab, Layout* layout, Output_section*,
1299 uint64_t subalign, uint64_t* dot_value, uint64_t*,
1300 Output_section**, std::string* fill,
1301 Input_section_list*);
1303 // Print for debugging.
1305 print(FILE* f) const;
1308 // An input section pattern.
1309 struct Input_section_pattern
1311 std::string pattern;
1312 bool pattern_is_wildcard;
1315 Input_section_pattern(const char* patterna, size_t patternlena,
1316 Sort_wildcard sorta)
1317 : pattern(patterna, patternlena),
1318 pattern_is_wildcard(is_wildcard_string(this->pattern.c_str())),
1323 typedef std::vector<Input_section_pattern> Input_section_patterns;
1325 // Filename_exclusions is a pair of filename pattern and a bool
1326 // indicating whether the filename is a wildcard.
1327 typedef std::vector<std::pair<std::string, bool> > Filename_exclusions;
1329 // Return whether STRING matches PATTERN, where IS_WILDCARD_PATTERN
1330 // indicates whether this is a wildcard pattern.
1332 match(const char* string, const char* pattern, bool is_wildcard_pattern)
1334 return (is_wildcard_pattern
1335 ? fnmatch(pattern, string, 0) == 0
1336 : strcmp(string, pattern) == 0);
1339 // See if we match a file name.
1341 match_file_name(const char* file_name) const;
1343 // The file name pattern. If this is the empty string, we match all
1345 std::string filename_pattern_;
1346 // Whether the file name pattern is a wildcard.
1347 bool filename_is_wildcard_;
1348 // How the file names should be sorted. This may only be
1349 // SORT_WILDCARD_NONE or SORT_WILDCARD_BY_NAME.
1350 Sort_wildcard filename_sort_;
1351 // The list of file names to exclude.
1352 Filename_exclusions filename_exclusions_;
1353 // The list of input section patterns.
1354 Input_section_patterns input_section_patterns_;
1355 // Whether to keep this section when garbage collecting.
1357 // The value of dot after including all matching sections.
1358 uint64_t final_dot_value_;
1359 // The section where dot is defined after including all matching
1361 Output_section* final_dot_section_;
1364 // Construct Output_section_element_input. The parser records strings
1365 // as pointers into a copy of the script file, which will go away when
1366 // parsing is complete. We make sure they are in std::string objects.
1368 Output_section_element_input::Output_section_element_input(
1369 const Input_section_spec* spec,
1371 : filename_pattern_(),
1372 filename_is_wildcard_(false),
1373 filename_sort_(spec->file.sort),
1374 filename_exclusions_(),
1375 input_section_patterns_(),
1377 final_dot_value_(0),
1378 final_dot_section_(NULL)
1380 // The filename pattern "*" is common, and matches all files. Turn
1381 // it into the empty string.
1382 if (spec->file.name.length != 1 || spec->file.name.value[0] != '*')
1383 this->filename_pattern_.assign(spec->file.name.value,
1384 spec->file.name.length);
1385 this->filename_is_wildcard_ = is_wildcard_string(this->filename_pattern_.c_str());
1387 if (spec->input_sections.exclude != NULL)
1389 for (String_list::const_iterator p =
1390 spec->input_sections.exclude->begin();
1391 p != spec->input_sections.exclude->end();
1394 bool is_wildcard = is_wildcard_string((*p).c_str());
1395 this->filename_exclusions_.push_back(std::make_pair(*p,
1400 if (spec->input_sections.sections != NULL)
1402 Input_section_patterns& isp(this->input_section_patterns_);
1403 for (String_sort_list::const_iterator p =
1404 spec->input_sections.sections->begin();
1405 p != spec->input_sections.sections->end();
1407 isp.push_back(Input_section_pattern(p->name.value, p->name.length,
1412 // See whether we match FILE_NAME.
1415 Output_section_element_input::match_file_name(const char* file_name) const
1417 if (!this->filename_pattern_.empty())
1419 // If we were called with no filename, we refuse to match a
1420 // pattern which requires a file name.
1421 if (file_name == NULL)
1424 if (!match(file_name, this->filename_pattern_.c_str(),
1425 this->filename_is_wildcard_))
1429 if (file_name != NULL)
1431 // Now we have to see whether FILE_NAME matches one of the
1432 // exclusion patterns, if any.
1433 for (Filename_exclusions::const_iterator p =
1434 this->filename_exclusions_.begin();
1435 p != this->filename_exclusions_.end();
1438 if (match(file_name, p->first.c_str(), p->second))
1446 // See whether we match FILE_NAME and SECTION_NAME. If we do then
1447 // KEEP indicates whether the section should survive garbage collection.
1450 Output_section_element_input::match_name(const char* file_name,
1451 const char* section_name,
1454 if (!this->match_file_name(file_name))
1457 *keep = this->keep_;
1459 // If there are no section name patterns, then we match.
1460 if (this->input_section_patterns_.empty())
1463 // See whether we match the section name patterns.
1464 for (Input_section_patterns::const_iterator p =
1465 this->input_section_patterns_.begin();
1466 p != this->input_section_patterns_.end();
1469 if (match(section_name, p->pattern.c_str(), p->pattern_is_wildcard))
1473 // We didn't match any section names, so we didn't match.
1477 // Information we use to sort the input sections.
1479 class Input_section_info
1482 Input_section_info(const Output_section::Input_section& input_section)
1483 : input_section_(input_section), section_name_(),
1484 size_(0), addralign_(1)
1487 // Return the simple input section.
1488 const Output_section::Input_section&
1489 input_section() const
1490 { return this->input_section_; }
1492 // Return the object.
1495 { return this->input_section_.relobj(); }
1497 // Return the section index.
1500 { return this->input_section_.shndx(); }
1502 // Return the section name.
1504 section_name() const
1505 { return this->section_name_; }
1507 // Set the section name.
1509 set_section_name(const std::string name)
1511 if (is_compressed_debug_section(name.c_str()))
1512 this->section_name_ = corresponding_uncompressed_section_name(name);
1514 this->section_name_ = name;
1517 // Return the section size.
1520 { return this->size_; }
1522 // Set the section size.
1524 set_size(uint64_t size)
1525 { this->size_ = size; }
1527 // Return the address alignment.
1530 { return this->addralign_; }
1532 // Set the address alignment.
1534 set_addralign(uint64_t addralign)
1535 { this->addralign_ = addralign; }
1538 // Input section, can be a relaxed section.
1539 Output_section::Input_section input_section_;
1540 // Name of the section.
1541 std::string section_name_;
1544 // Address alignment.
1545 uint64_t addralign_;
1548 // A class to sort the input sections.
1550 class Input_section_sorter
1553 Input_section_sorter(Sort_wildcard filename_sort, Sort_wildcard section_sort)
1554 : filename_sort_(filename_sort), section_sort_(section_sort)
1558 operator()(const Input_section_info&, const Input_section_info&) const;
1561 static unsigned long
1562 get_init_priority(const char*);
1564 Sort_wildcard filename_sort_;
1565 Sort_wildcard section_sort_;
1568 // Return a relative priority of the section with the specified NAME
1569 // (a lower value meand a higher priority), or 0 if it should be compared
1570 // with others as strings.
1571 // The implementation of this function is copied from ld/ldlang.c.
1574 Input_section_sorter::get_init_priority(const char* name)
1577 unsigned long init_priority;
1579 // GCC uses the following section names for the init_priority
1580 // attribute with numerical values 101 and 65535 inclusive. A
1581 // lower value means a higher priority.
1583 // 1: .init_array.NNNN/.fini_array.NNNN: Where NNNN is the
1584 // decimal numerical value of the init_priority attribute.
1585 // The order of execution in .init_array is forward and
1586 // .fini_array is backward.
1587 // 2: .ctors.NNNN/.dtors.NNNN: Where NNNN is 65535 minus the
1588 // decimal numerical value of the init_priority attribute.
1589 // The order of execution in .ctors is backward and .dtors
1592 if (strncmp(name, ".init_array.", 12) == 0
1593 || strncmp(name, ".fini_array.", 12) == 0)
1595 init_priority = strtoul(name + 12, &end, 10);
1596 return *end ? 0 : init_priority;
1598 else if (strncmp(name, ".ctors.", 7) == 0
1599 || strncmp(name, ".dtors.", 7) == 0)
1601 init_priority = strtoul(name + 7, &end, 10);
1602 return *end ? 0 : 65535 - init_priority;
1609 Input_section_sorter::operator()(const Input_section_info& isi1,
1610 const Input_section_info& isi2) const
1612 if (this->section_sort_ == SORT_WILDCARD_BY_INIT_PRIORITY)
1614 unsigned long ip1 = get_init_priority(isi1.section_name().c_str());
1615 unsigned long ip2 = get_init_priority(isi2.section_name().c_str());
1616 if (ip1 != 0 && ip2 != 0 && ip1 != ip2)
1619 if (this->section_sort_ == SORT_WILDCARD_BY_NAME
1620 || this->section_sort_ == SORT_WILDCARD_BY_NAME_BY_ALIGNMENT
1621 || (this->section_sort_ == SORT_WILDCARD_BY_ALIGNMENT_BY_NAME
1622 && isi1.addralign() == isi2.addralign())
1623 || this->section_sort_ == SORT_WILDCARD_BY_INIT_PRIORITY)
1625 if (isi1.section_name() != isi2.section_name())
1626 return isi1.section_name() < isi2.section_name();
1628 if (this->section_sort_ == SORT_WILDCARD_BY_ALIGNMENT
1629 || this->section_sort_ == SORT_WILDCARD_BY_NAME_BY_ALIGNMENT
1630 || this->section_sort_ == SORT_WILDCARD_BY_ALIGNMENT_BY_NAME)
1632 if (isi1.addralign() != isi2.addralign())
1633 return isi1.addralign() < isi2.addralign();
1635 if (this->filename_sort_ == SORT_WILDCARD_BY_NAME)
1637 if (isi1.relobj()->name() != isi2.relobj()->name())
1638 return (isi1.relobj()->name() < isi2.relobj()->name());
1641 // Otherwise we leave them in the same order.
1645 // Set the section address. Look in INPUT_SECTIONS for sections which
1646 // match this spec, sort them as specified, and add them to the output
1650 Output_section_element_input::set_section_addresses(
1653 Output_section* output_section,
1655 uint64_t* dot_value,
1657 Output_section** dot_section,
1659 Input_section_list* input_sections)
1661 // We build a list of sections which match each
1662 // Input_section_pattern.
1664 // If none of the patterns specify a sort option, we throw all
1665 // matching input sections into a single bin, in the order we
1666 // find them. Otherwise, we put matching input sections into
1667 // a separate bin for each pattern, and sort each one as
1668 // specified. Thus, an input section spec like this:
1670 // will group all .foo and .bar sections in the order seen,
1673 // will group all .foo sections followed by all .bar sections.
1674 // This matches Gnu ld behavior.
1676 // Things get really weird, though, when you add a sort spec
1677 // on some, but not all, of the patterns, like this:
1678 // *(SORT_BY_NAME(.foo) .bar)
1679 // We do not attempt to match Gnu ld behavior in this case.
1681 typedef std::vector<std::vector<Input_section_info> > Matching_sections;
1682 size_t input_pattern_count = this->input_section_patterns_.size();
1683 size_t bin_count = 1;
1684 bool any_patterns_with_sort = false;
1685 for (size_t i = 0; i < input_pattern_count; ++i)
1687 const Input_section_pattern& isp(this->input_section_patterns_[i]);
1688 if (isp.sort != SORT_WILDCARD_NONE)
1689 any_patterns_with_sort = true;
1691 if (any_patterns_with_sort)
1692 bin_count = input_pattern_count;
1693 Matching_sections matching_sections(bin_count);
1695 // Look through the list of sections for this output section. Add
1696 // each one which matches to one of the elements of
1697 // MATCHING_SECTIONS.
1699 Input_section_list::iterator p = input_sections->begin();
1700 while (p != input_sections->end())
1702 Relobj* relobj = p->relobj();
1703 unsigned int shndx = p->shndx();
1704 Input_section_info isi(*p);
1706 // Calling section_name and section_addralign is not very
1709 // Lock the object so that we can get information about the
1710 // section. This is OK since we know we are single-threaded
1713 const Task* task = reinterpret_cast<const Task*>(-1);
1714 Task_lock_obj<Object> tl(task, relobj);
1716 isi.set_section_name(relobj->section_name(shndx));
1717 if (p->is_relaxed_input_section())
1719 // We use current data size because relaxed section sizes may not
1720 // have finalized yet.
1721 isi.set_size(p->relaxed_input_section()->current_data_size());
1722 isi.set_addralign(p->relaxed_input_section()->addralign());
1726 isi.set_size(relobj->section_size(shndx));
1727 isi.set_addralign(relobj->section_addralign(shndx));
1731 if (!this->match_file_name(relobj->name().c_str()))
1733 else if (this->input_section_patterns_.empty())
1735 matching_sections[0].push_back(isi);
1736 p = input_sections->erase(p);
1741 for (i = 0; i < input_pattern_count; ++i)
1743 const Input_section_pattern&
1744 isp(this->input_section_patterns_[i]);
1745 if (match(isi.section_name().c_str(), isp.pattern.c_str(),
1746 isp.pattern_is_wildcard))
1750 if (i >= input_pattern_count)
1756 matching_sections[i].push_back(isi);
1757 p = input_sections->erase(p);
1762 // Look through MATCHING_SECTIONS. Sort each one as specified,
1763 // using a stable sort so that we get the default order when
1764 // sections are otherwise equal. Add each input section to the
1767 uint64_t dot = *dot_value;
1768 for (size_t i = 0; i < bin_count; ++i)
1770 if (matching_sections[i].empty())
1773 gold_assert(output_section != NULL);
1775 const Input_section_pattern& isp(this->input_section_patterns_[i]);
1776 if (isp.sort != SORT_WILDCARD_NONE
1777 || this->filename_sort_ != SORT_WILDCARD_NONE)
1778 std::stable_sort(matching_sections[i].begin(),
1779 matching_sections[i].end(),
1780 Input_section_sorter(this->filename_sort_,
1783 for (std::vector<Input_section_info>::const_iterator p =
1784 matching_sections[i].begin();
1785 p != matching_sections[i].end();
1788 // Override the original address alignment if SUBALIGN is specified.
1789 // We need to make a copy of the input section to modify the
1791 Output_section::Input_section sis(p->input_section());
1793 uint64_t this_subalign = sis.addralign();
1794 if (!sis.is_input_section())
1795 sis.output_section_data()->finalize_data_size();
1796 uint64_t data_size = sis.data_size();
1799 this_subalign = subalign;
1800 sis.set_addralign(subalign);
1803 uint64_t address = align_address(dot, this_subalign);
1805 if (address > dot && !fill->empty())
1807 section_size_type length =
1808 convert_to_section_size_type(address - dot);
1809 std::string this_fill = this->get_fill_string(fill, length);
1810 Output_section_data* posd = new Output_data_const(this_fill, 0);
1811 output_section->add_output_section_data(posd);
1812 layout->new_output_section_data_from_script(posd);
1815 output_section->add_script_input_section(sis);
1816 dot = address + data_size;
1820 // An SHF_TLS/SHT_NOBITS section does not take up any
1822 if (output_section == NULL
1823 || (output_section->flags() & elfcpp::SHF_TLS) == 0
1824 || output_section->type() != elfcpp::SHT_NOBITS)
1827 this->final_dot_value_ = *dot_value;
1828 this->final_dot_section_ = *dot_section;
1831 // Print for debugging.
1834 Output_section_element_input::print(FILE* f) const
1839 fprintf(f, "KEEP(");
1841 if (!this->filename_pattern_.empty())
1843 bool need_close_paren = false;
1844 switch (this->filename_sort_)
1846 case SORT_WILDCARD_NONE:
1848 case SORT_WILDCARD_BY_NAME:
1849 fprintf(f, "SORT_BY_NAME(");
1850 need_close_paren = true;
1856 fprintf(f, "%s", this->filename_pattern_.c_str());
1858 if (need_close_paren)
1862 if (!this->input_section_patterns_.empty()
1863 || !this->filename_exclusions_.empty())
1867 bool need_space = false;
1868 if (!this->filename_exclusions_.empty())
1870 fprintf(f, "EXCLUDE_FILE(");
1871 bool need_comma = false;
1872 for (Filename_exclusions::const_iterator p =
1873 this->filename_exclusions_.begin();
1874 p != this->filename_exclusions_.end();
1879 fprintf(f, "%s", p->first.c_str());
1886 for (Input_section_patterns::const_iterator p =
1887 this->input_section_patterns_.begin();
1888 p != this->input_section_patterns_.end();
1894 int close_parens = 0;
1897 case SORT_WILDCARD_NONE:
1899 case SORT_WILDCARD_BY_NAME:
1900 fprintf(f, "SORT_BY_NAME(");
1903 case SORT_WILDCARD_BY_ALIGNMENT:
1904 fprintf(f, "SORT_BY_ALIGNMENT(");
1907 case SORT_WILDCARD_BY_NAME_BY_ALIGNMENT:
1908 fprintf(f, "SORT_BY_NAME(SORT_BY_ALIGNMENT(");
1911 case SORT_WILDCARD_BY_ALIGNMENT_BY_NAME:
1912 fprintf(f, "SORT_BY_ALIGNMENT(SORT_BY_NAME(");
1915 case SORT_WILDCARD_BY_INIT_PRIORITY:
1916 fprintf(f, "SORT_BY_INIT_PRIORITY(");
1923 fprintf(f, "%s", p->pattern.c_str());
1925 for (int i = 0; i < close_parens; ++i)
1940 // An output section.
1942 class Output_section_definition : public Sections_element
1945 typedef Output_section_element::Input_section_list Input_section_list;
1947 Output_section_definition(const char* name, size_t namelen,
1948 const Parser_output_section_header* header);
1950 // Finish the output section with the information in the trailer.
1952 finish(const Parser_output_section_trailer* trailer);
1954 // Add a symbol to be defined.
1956 add_symbol_assignment(const char* name, size_t length, Expression* value,
1957 bool provide, bool hidden);
1959 // Add an assignment to the special dot symbol.
1961 add_dot_assignment(Expression* value);
1963 // Add an assertion.
1965 add_assertion(Expression* check, const char* message, size_t messagelen);
1967 // Add a data item to the current output section.
1969 add_data(int size, bool is_signed, Expression* val);
1971 // Add a setting for the fill value.
1973 add_fill(Expression* val);
1975 // Add an input section specification.
1977 add_input_section(const Input_section_spec* spec, bool keep);
1979 // Return whether the output section is relro.
1982 { return this->is_relro_; }
1984 // Record that the output section is relro.
1987 { this->is_relro_ = true; }
1989 // Create any required output sections.
1991 create_sections(Layout*);
1993 // Add any symbols being defined to the symbol table.
1995 add_symbols_to_table(Symbol_table* symtab);
1997 // Finalize symbols and check assertions.
1999 finalize_symbols(Symbol_table*, const Layout*, uint64_t*);
2001 // Return the output section name to use for an input file name and
2004 output_section_name(const char* file_name, const char* section_name,
2005 Output_section***, Script_sections::Section_type*,
2008 // Initialize OSP with an output section.
2010 orphan_section_init(Orphan_section_placement* osp,
2011 Script_sections::Elements_iterator p)
2012 { osp->output_section_init(this->name_, this->output_section_, p); }
2014 // Set the section address.
2016 set_section_addresses(Symbol_table* symtab, Layout* layout,
2017 uint64_t* dot_value, uint64_t*,
2018 uint64_t* load_address);
2020 // Check a constraint (ONLY_IF_RO, etc.) on an output section. If
2021 // this section is constrained, and the input sections do not match,
2022 // return the constraint, and set *POSD.
2024 check_constraint(Output_section_definition** posd);
2026 // See if this is the alternate output section for a constrained
2027 // output section. If it is, transfer the Output_section and return
2028 // true. Otherwise return false.
2030 alternate_constraint(Output_section_definition*, Section_constraint);
2032 // Get the list of segments to use for an allocated section when
2033 // using a PHDRS clause.
2035 allocate_to_segment(String_list** phdrs_list, bool* orphan);
2037 // Look for an output section by name and return the address, the
2038 // load address, the alignment, and the size. This is used when an
2039 // expression refers to an output section which was not actually
2040 // created. This returns true if the section was found, false
2043 get_output_section_info(const char*, uint64_t*, uint64_t*, uint64_t*,
2046 // Return the associated Output_section if there is one.
2048 get_output_section() const
2049 { return this->output_section_; }
2051 // Print the contents to the FILE. This is for debugging.
2055 // Return the output section type if specified or Script_sections::ST_NONE.
2056 Script_sections::Section_type
2057 section_type() const;
2059 // Store the memory region to use.
2061 set_memory_region(Memory_region*, bool set_vma);
2064 set_section_vma(Expression* address)
2065 { this->address_ = address; }
2068 set_section_lma(Expression* address)
2069 { this->load_address_ = address; }
2072 get_section_name() const
2073 { return this->name_; }
2077 script_section_type_name(Script_section_type);
2079 typedef std::vector<Output_section_element*> Output_section_elements;
2081 // The output section name.
2083 // The address. This may be NULL.
2084 Expression* address_;
2085 // The load address. This may be NULL.
2086 Expression* load_address_;
2087 // The alignment. This may be NULL.
2089 // The input section alignment. This may be NULL.
2090 Expression* subalign_;
2091 // The constraint, if any.
2092 Section_constraint constraint_;
2093 // The fill value. This may be NULL.
2095 // The list of segments this section should go into. This may be
2097 String_list* phdrs_;
2098 // The list of elements defining the section.
2099 Output_section_elements elements_;
2100 // The Output_section created for this definition. This will be
2101 // NULL if none was created.
2102 Output_section* output_section_;
2103 // The address after it has been evaluated.
2104 uint64_t evaluated_address_;
2105 // The load address after it has been evaluated.
2106 uint64_t evaluated_load_address_;
2107 // The alignment after it has been evaluated.
2108 uint64_t evaluated_addralign_;
2109 // The output section is relro.
2111 // The output section type if specified.
2112 enum Script_section_type script_section_type_;
2117 Output_section_definition::Output_section_definition(
2120 const Parser_output_section_header* header)
2121 : name_(name, namelen),
2122 address_(header->address),
2123 load_address_(header->load_address),
2124 align_(header->align),
2125 subalign_(header->subalign),
2126 constraint_(header->constraint),
2130 output_section_(NULL),
2131 evaluated_address_(0),
2132 evaluated_load_address_(0),
2133 evaluated_addralign_(0),
2135 script_section_type_(header->section_type)
2139 // Finish an output section.
2142 Output_section_definition::finish(const Parser_output_section_trailer* trailer)
2144 this->fill_ = trailer->fill;
2145 this->phdrs_ = trailer->phdrs;
2148 // Add a symbol to be defined.
2151 Output_section_definition::add_symbol_assignment(const char* name,
2157 Output_section_element* p = new Output_section_element_assignment(name,
2162 this->elements_.push_back(p);
2165 // Add an assignment to the special dot symbol.
2168 Output_section_definition::add_dot_assignment(Expression* value)
2170 Output_section_element* p = new Output_section_element_dot_assignment(value);
2171 this->elements_.push_back(p);
2174 // Add an assertion.
2177 Output_section_definition::add_assertion(Expression* check,
2178 const char* message,
2181 Output_section_element* p = new Output_section_element_assertion(check,
2184 this->elements_.push_back(p);
2187 // Add a data item to the current output section.
2190 Output_section_definition::add_data(int size, bool is_signed, Expression* val)
2192 Output_section_element* p = new Output_section_element_data(size, is_signed,
2194 this->elements_.push_back(p);
2197 // Add a setting for the fill value.
2200 Output_section_definition::add_fill(Expression* val)
2202 Output_section_element* p = new Output_section_element_fill(val);
2203 this->elements_.push_back(p);
2206 // Add an input section specification.
2209 Output_section_definition::add_input_section(const Input_section_spec* spec,
2212 Output_section_element* p = new Output_section_element_input(spec, keep);
2213 this->elements_.push_back(p);
2216 // Create any required output sections. We need an output section if
2217 // there is a data statement here.
2220 Output_section_definition::create_sections(Layout* layout)
2222 if (this->output_section_ != NULL)
2224 for (Output_section_elements::const_iterator p = this->elements_.begin();
2225 p != this->elements_.end();
2228 if ((*p)->needs_output_section())
2230 const char* name = this->name_.c_str();
2231 this->output_section_ =
2232 layout->make_output_section_for_script(name, this->section_type());
2238 // Add any symbols being defined to the symbol table.
2241 Output_section_definition::add_symbols_to_table(Symbol_table* symtab)
2243 for (Output_section_elements::iterator p = this->elements_.begin();
2244 p != this->elements_.end();
2246 (*p)->add_symbols_to_table(symtab);
2249 // Finalize symbols and check assertions.
2252 Output_section_definition::finalize_symbols(Symbol_table* symtab,
2253 const Layout* layout,
2254 uint64_t* dot_value)
2256 if (this->output_section_ != NULL)
2257 *dot_value = this->output_section_->address();
2260 uint64_t address = *dot_value;
2261 if (this->address_ != NULL)
2263 address = this->address_->eval_with_dot(symtab, layout, true,
2267 if (this->align_ != NULL)
2269 uint64_t align = this->align_->eval_with_dot(symtab, layout, true,
2272 address = align_address(address, align);
2274 *dot_value = address;
2277 Output_section* dot_section = this->output_section_;
2278 for (Output_section_elements::iterator p = this->elements_.begin();
2279 p != this->elements_.end();
2281 (*p)->finalize_symbols(symtab, layout, dot_value, &dot_section);
2284 // Return the output section name to use for an input section name.
2287 Output_section_definition::output_section_name(
2288 const char* file_name,
2289 const char* section_name,
2290 Output_section*** slot,
2291 Script_sections::Section_type* psection_type,
2294 // If the input section is linker-created, just look for a match
2295 // on the output section name.
2296 if (file_name == NULL && this->name_ != "/DISCARD/")
2298 if (this->name_ != section_name)
2300 *slot = &this->output_section_;
2301 *psection_type = this->section_type();
2302 return this->name_.c_str();
2305 // Ask each element whether it matches NAME.
2306 for (Output_section_elements::const_iterator p = this->elements_.begin();
2307 p != this->elements_.end();
2310 if ((*p)->match_name(file_name, section_name, keep))
2312 // We found a match for NAME, which means that it should go
2313 // into this output section.
2314 *slot = &this->output_section_;
2315 *psection_type = this->section_type();
2316 return this->name_.c_str();
2320 // We don't know about this section name.
2324 // Return true if memory from START to START + LENGTH is contained
2325 // within a memory region.
2328 Script_sections::block_in_region(Symbol_table* symtab, Layout* layout,
2329 uint64_t start, uint64_t length) const
2331 if (this->memory_regions_ == NULL)
2334 for (Memory_regions::const_iterator mr = this->memory_regions_->begin();
2335 mr != this->memory_regions_->end();
2338 uint64_t s = (*mr)->start_address()->eval(symtab, layout, false);
2339 uint64_t l = (*mr)->length()->eval(symtab, layout, false);
2342 && (s + l) >= (start + length))
2349 // Find a memory region that should be used by a given output SECTION.
2350 // If provided set PREVIOUS_SECTION_RETURN to point to the last section
2351 // that used the return memory region.
2354 Script_sections::find_memory_region(
2355 Output_section_definition* section,
2356 bool find_vma_region,
2358 Output_section_definition** previous_section_return)
2360 if (previous_section_return != NULL)
2361 * previous_section_return = NULL;
2363 // Walk the memory regions specified in this script, if any.
2364 if (this->memory_regions_ == NULL)
2367 // The /DISCARD/ section never gets assigned to any region.
2368 if (section->get_section_name() == "/DISCARD/")
2371 Memory_region* first_match = NULL;
2373 // First check to see if a region has been assigned to this section.
2374 for (Memory_regions::const_iterator mr = this->memory_regions_->begin();
2375 mr != this->memory_regions_->end();
2378 if (find_vma_region)
2380 for (Memory_region::Section_list::const_iterator s =
2381 (*mr)->get_vma_section_list_start();
2382 s != (*mr)->get_vma_section_list_end();
2384 if ((*s) == section)
2386 (*mr)->set_last_section(section);
2392 for (Memory_region::Section_list::const_iterator s =
2393 (*mr)->get_lma_section_list_start();
2394 s != (*mr)->get_lma_section_list_end();
2396 if ((*s) == section)
2398 (*mr)->set_last_section(section);
2405 // Make a note of the first memory region whose attributes
2406 // are compatible with the section. If we do not find an
2407 // explicit region assignment, then we will return this region.
2408 Output_section* out_sec = section->get_output_section();
2409 if (first_match == NULL
2411 && (*mr)->attributes_compatible(out_sec->flags(),
2417 // With LMA computations, if an explicit region has not been specified then
2418 // we will want to set the difference between the VMA and the LMA of the
2419 // section were searching for to be the same as the difference between the
2420 // VMA and LMA of the last section to be added to first matched region.
2421 // Hence, if it was asked for, we return a pointer to the last section
2422 // known to be used by the first matched region.
2423 if (first_match != NULL
2424 && previous_section_return != NULL)
2425 *previous_section_return = first_match->get_last_section();
2430 // Set the section address. Note that the OUTPUT_SECTION_ field will
2431 // be NULL if no input sections were mapped to this output section.
2432 // We still have to adjust dot and process symbol assignments.
2435 Output_section_definition::set_section_addresses(Symbol_table* symtab,
2437 uint64_t* dot_value,
2438 uint64_t* dot_alignment,
2439 uint64_t* load_address)
2441 Memory_region* vma_region = NULL;
2442 Memory_region* lma_region = NULL;
2443 Script_sections* script_sections =
2444 layout->script_options()->script_sections();
2446 uint64_t old_dot_value = *dot_value;
2447 uint64_t old_load_address = *load_address;
2449 // If input section sorting is requested via --section-ordering-file or
2450 // linker plugins, then do it here. This is important because we want
2451 // any sorting specified in the linker scripts, which will be done after
2452 // this, to take precedence. The final order of input sections is then
2453 // guaranteed to be according to the linker script specification.
2454 if (this->output_section_ != NULL
2455 && this->output_section_->input_section_order_specified())
2456 this->output_section_->sort_attached_input_sections();
2458 // Decide the start address for the section. The algorithm is:
2459 // 1) If an address has been specified in a linker script, use that.
2460 // 2) Otherwise if a memory region has been specified for the section,
2461 // use the next free address in the region.
2462 // 3) Otherwise if memory regions have been specified find the first
2463 // region whose attributes are compatible with this section and
2464 // install it into that region.
2465 // 4) Otherwise use the current location counter.
2467 if (this->output_section_ != NULL
2468 // Check for --section-start.
2469 && parameters->options().section_start(this->output_section_->name(),
2472 else if (this->address_ == NULL)
2474 vma_region = script_sections->find_memory_region(this, true, false, NULL);
2475 if (vma_region != NULL)
2476 address = vma_region->get_current_address()->eval(symtab, layout,
2479 address = *dot_value;
2483 vma_region = script_sections->find_memory_region(this, true, true, NULL);
2484 address = this->address_->eval_with_dot(symtab, layout, true,
2485 *dot_value, NULL, NULL,
2486 dot_alignment, false);
2487 if (vma_region != NULL)
2488 vma_region->set_address(address, symtab, layout);
2492 if (this->align_ == NULL)
2494 if (this->output_section_ == NULL)
2497 align = this->output_section_->addralign();
2501 Output_section* align_section;
2502 align = this->align_->eval_with_dot(symtab, layout, true, *dot_value,
2503 NULL, &align_section, NULL, false);
2504 if (align_section != NULL)
2505 gold_warning(_("alignment of section %s is not absolute"),
2506 this->name_.c_str());
2507 if (this->output_section_ != NULL)
2508 this->output_section_->set_addralign(align);
2512 if (this->subalign_ == NULL)
2516 Output_section* subalign_section;
2517 subalign = this->subalign_->eval_with_dot(symtab, layout, true,
2519 &subalign_section, NULL,
2521 if (subalign_section != NULL)
2522 gold_warning(_("subalign of section %s is not absolute"),
2523 this->name_.c_str());
2525 // Reserve a value of 0 to mean there is no SUBALIGN property.
2529 // The external alignment of the output section must be at least
2530 // as large as that of the input sections. If there is no
2531 // explicit ALIGN property, we set the output section alignment
2532 // to match the input section alignment.
2533 if (align < subalign || this->align_ == NULL)
2536 this->output_section_->set_addralign(align);
2540 address = align_address(address, align);
2542 uint64_t start_address = address;
2544 *dot_value = address;
2546 // Except for NOLOAD sections, the address of non-SHF_ALLOC sections is
2547 // forced to zero, regardless of what the linker script wants.
2548 if (this->output_section_ != NULL
2549 && ((this->output_section_->flags() & elfcpp::SHF_ALLOC) != 0
2550 || this->output_section_->is_noload()))
2551 this->output_section_->set_address(address);
2553 this->evaluated_address_ = address;
2554 this->evaluated_addralign_ = align;
2558 if (this->load_address_ == NULL)
2560 Output_section_definition* previous_section;
2562 // Determine if an LMA region has been set for this section.
2563 lma_region = script_sections->find_memory_region(this, false, false,
2566 if (lma_region != NULL)
2568 if (previous_section == NULL)
2569 // The LMA address was explicitly set to the given region.
2570 laddr = lma_region->get_current_address()->eval(symtab, layout,
2574 // We are not going to use the discovered lma_region, so
2575 // make sure that we do not update it in the code below.
2578 if (this->address_ != NULL || previous_section == this)
2580 // Either an explicit VMA address has been set, or an
2581 // explicit VMA region has been set, so set the LMA equal to
2587 // The LMA address was not explicitly or implicitly set.
2589 // We have been given the first memory region that is
2590 // compatible with the current section and a pointer to the
2591 // last section to use this region. Set the LMA of this
2592 // section so that the difference between its' VMA and LMA
2593 // is the same as the difference between the VMA and LMA of
2594 // the last section in the given region.
2595 laddr = address + (previous_section->evaluated_load_address_
2596 - previous_section->evaluated_address_);
2600 if (this->output_section_ != NULL)
2601 this->output_section_->set_load_address(laddr);
2605 // Do not set the load address of the output section, if one exists.
2606 // This allows future sections to determine what the load address
2607 // should be. If none is ever set, it will default to being the
2608 // same as the vma address.
2614 laddr = this->load_address_->eval_with_dot(symtab, layout, true,
2616 this->output_section_,
2618 if (this->output_section_ != NULL)
2619 this->output_section_->set_load_address(laddr);
2622 this->evaluated_load_address_ = laddr;
2625 if (this->fill_ != NULL)
2627 // FIXME: The GNU linker supports fill values of arbitrary
2629 Output_section* fill_section;
2630 uint64_t fill_val = this->fill_->eval_with_dot(symtab, layout, true,
2632 NULL, &fill_section,
2634 if (fill_section != NULL)
2635 gold_warning(_("fill of section %s is not absolute"),
2636 this->name_.c_str());
2637 unsigned char fill_buff[4];
2638 elfcpp::Swap_unaligned<32, true>::writeval(fill_buff, fill_val);
2639 fill.assign(reinterpret_cast<char*>(fill_buff), 4);
2642 Input_section_list input_sections;
2643 if (this->output_section_ != NULL)
2645 // Get the list of input sections attached to this output
2646 // section. This will leave the output section with only
2647 // Output_section_data entries.
2648 address += this->output_section_->get_input_sections(address,
2651 *dot_value = address;
2654 Output_section* dot_section = this->output_section_;
2655 for (Output_section_elements::iterator p = this->elements_.begin();
2656 p != this->elements_.end();
2658 (*p)->set_section_addresses(symtab, layout, this->output_section_,
2659 subalign, dot_value, dot_alignment,
2660 &dot_section, &fill, &input_sections);
2662 gold_assert(input_sections.empty());
2664 if (vma_region != NULL)
2666 // Update the VMA region being used by the section now that we know how
2667 // big it is. Use the current address in the region, rather than
2668 // start_address because that might have been aligned upwards and we
2669 // need to allow for the padding.
2670 Expression* addr = vma_region->get_current_address();
2671 uint64_t size = *dot_value - addr->eval(symtab, layout, false);
2673 vma_region->increment_offset(this->get_section_name(), size,
2677 // If the LMA region is different from the VMA region, then increment the
2678 // offset there as well. Note that we use the same "dot_value -
2679 // start_address" formula that is used in the load_address assignment below.
2680 if (lma_region != NULL && lma_region != vma_region)
2681 lma_region->increment_offset(this->get_section_name(),
2682 *dot_value - start_address,
2685 // Compute the load address for the following section.
2686 if (this->output_section_ == NULL)
2687 *load_address = *dot_value;
2688 else if (this->load_address_ == NULL)
2690 if (lma_region == NULL)
2691 *load_address = *dot_value;
2694 lma_region->get_current_address()->eval(symtab, layout, false);
2697 *load_address = (this->output_section_->load_address()
2698 + (*dot_value - start_address));
2700 if (this->output_section_ != NULL)
2702 if (this->is_relro_)
2703 this->output_section_->set_is_relro();
2705 this->output_section_->clear_is_relro();
2707 // If this is a NOLOAD section, keep dot and load address unchanged.
2708 if (this->output_section_->is_noload())
2710 *dot_value = old_dot_value;
2711 *load_address = old_load_address;
2716 // Check a constraint (ONLY_IF_RO, etc.) on an output section. If
2717 // this section is constrained, and the input sections do not match,
2718 // return the constraint, and set *POSD.
2721 Output_section_definition::check_constraint(Output_section_definition** posd)
2723 switch (this->constraint_)
2725 case CONSTRAINT_NONE:
2726 return CONSTRAINT_NONE;
2728 case CONSTRAINT_ONLY_IF_RO:
2729 if (this->output_section_ != NULL
2730 && (this->output_section_->flags() & elfcpp::SHF_WRITE) != 0)
2733 return CONSTRAINT_ONLY_IF_RO;
2735 return CONSTRAINT_NONE;
2737 case CONSTRAINT_ONLY_IF_RW:
2738 if (this->output_section_ != NULL
2739 && (this->output_section_->flags() & elfcpp::SHF_WRITE) == 0)
2742 return CONSTRAINT_ONLY_IF_RW;
2744 return CONSTRAINT_NONE;
2746 case CONSTRAINT_SPECIAL:
2747 if (this->output_section_ != NULL)
2748 gold_error(_("SPECIAL constraints are not implemented"));
2749 return CONSTRAINT_NONE;
2756 // See if this is the alternate output section for a constrained
2757 // output section. If it is, transfer the Output_section and return
2758 // true. Otherwise return false.
2761 Output_section_definition::alternate_constraint(
2762 Output_section_definition* posd,
2763 Section_constraint constraint)
2765 if (this->name_ != posd->name_)
2770 case CONSTRAINT_ONLY_IF_RO:
2771 if (this->constraint_ != CONSTRAINT_ONLY_IF_RW)
2775 case CONSTRAINT_ONLY_IF_RW:
2776 if (this->constraint_ != CONSTRAINT_ONLY_IF_RO)
2784 // We have found the alternate constraint. We just need to move
2785 // over the Output_section. When constraints are used properly,
2786 // THIS should not have an output_section pointer, as all the input
2787 // sections should have matched the other definition.
2789 if (this->output_section_ != NULL)
2790 gold_error(_("mismatched definition for constrained sections"));
2792 this->output_section_ = posd->output_section_;
2793 posd->output_section_ = NULL;
2795 if (this->is_relro_)
2796 this->output_section_->set_is_relro();
2798 this->output_section_->clear_is_relro();
2803 // Get the list of segments to use for an allocated section when using
2807 Output_section_definition::allocate_to_segment(String_list** phdrs_list,
2810 // Update phdrs_list even if we don't have an output section. It
2811 // might be used by the following sections.
2812 if (this->phdrs_ != NULL)
2813 *phdrs_list = this->phdrs_;
2815 if (this->output_section_ == NULL)
2817 if ((this->output_section_->flags() & elfcpp::SHF_ALLOC) == 0)
2820 return this->output_section_;
2823 // Look for an output section by name and return the address, the load
2824 // address, the alignment, and the size. This is used when an
2825 // expression refers to an output section which was not actually
2826 // created. This returns true if the section was found, false
2830 Output_section_definition::get_output_section_info(const char* name,
2832 uint64_t* load_address,
2833 uint64_t* addralign,
2834 uint64_t* size) const
2836 if (this->name_ != name)
2839 if (this->output_section_ != NULL)
2841 *address = this->output_section_->address();
2842 if (this->output_section_->has_load_address())
2843 *load_address = this->output_section_->load_address();
2845 *load_address = *address;
2846 *addralign = this->output_section_->addralign();
2847 *size = this->output_section_->current_data_size();
2851 *address = this->evaluated_address_;
2852 *load_address = this->evaluated_load_address_;
2853 *addralign = this->evaluated_addralign_;
2860 // Print for debugging.
2863 Output_section_definition::print(FILE* f) const
2865 fprintf(f, " %s ", this->name_.c_str());
2867 if (this->address_ != NULL)
2869 this->address_->print(f);
2873 if (this->script_section_type_ != SCRIPT_SECTION_TYPE_NONE)
2875 this->script_section_type_name(this->script_section_type_));
2879 if (this->load_address_ != NULL)
2882 this->load_address_->print(f);
2886 if (this->align_ != NULL)
2888 fprintf(f, "ALIGN(");
2889 this->align_->print(f);
2893 if (this->subalign_ != NULL)
2895 fprintf(f, "SUBALIGN(");
2896 this->subalign_->print(f);
2902 for (Output_section_elements::const_iterator p = this->elements_.begin();
2903 p != this->elements_.end();
2909 if (this->fill_ != NULL)
2912 this->fill_->print(f);
2915 if (this->phdrs_ != NULL)
2917 for (String_list::const_iterator p = this->phdrs_->begin();
2918 p != this->phdrs_->end();
2920 fprintf(f, " :%s", p->c_str());
2926 Script_sections::Section_type
2927 Output_section_definition::section_type() const
2929 switch (this->script_section_type_)
2931 case SCRIPT_SECTION_TYPE_NONE:
2932 return Script_sections::ST_NONE;
2933 case SCRIPT_SECTION_TYPE_NOLOAD:
2934 return Script_sections::ST_NOLOAD;
2935 case SCRIPT_SECTION_TYPE_COPY:
2936 case SCRIPT_SECTION_TYPE_DSECT:
2937 case SCRIPT_SECTION_TYPE_INFO:
2938 case SCRIPT_SECTION_TYPE_OVERLAY:
2939 // There are not really support so we treat them as ST_NONE. The
2940 // parse should have issued errors for them already.
2941 return Script_sections::ST_NONE;
2947 // Return the name of a script section type.
2950 Output_section_definition::script_section_type_name(
2951 Script_section_type script_section_type)
2953 switch (script_section_type)
2955 case SCRIPT_SECTION_TYPE_NONE:
2957 case SCRIPT_SECTION_TYPE_NOLOAD:
2959 case SCRIPT_SECTION_TYPE_DSECT:
2961 case SCRIPT_SECTION_TYPE_COPY:
2963 case SCRIPT_SECTION_TYPE_INFO:
2965 case SCRIPT_SECTION_TYPE_OVERLAY:
2973 Output_section_definition::set_memory_region(Memory_region* mr, bool set_vma)
2975 gold_assert(mr != NULL);
2976 // Add the current section to the specified region's list.
2977 mr->add_section(this, set_vma);
2980 // An output section created to hold orphaned input sections. These
2981 // do not actually appear in linker scripts. However, for convenience
2982 // when setting the output section addresses, we put a marker to these
2983 // sections in the appropriate place in the list of SECTIONS elements.
2985 class Orphan_output_section : public Sections_element
2988 Orphan_output_section(Output_section* os)
2992 // Return whether the orphan output section is relro. We can just
2993 // check the output section because we always set the flag, if
2994 // needed, just after we create the Orphan_output_section.
2997 { return this->os_->is_relro(); }
2999 // Initialize OSP with an output section. This should have been
3002 orphan_section_init(Orphan_section_placement*,
3003 Script_sections::Elements_iterator)
3004 { gold_unreachable(); }
3006 // Set section addresses.
3008 set_section_addresses(Symbol_table*, Layout*, uint64_t*, uint64_t*,
3011 // Get the list of segments to use for an allocated section when
3012 // using a PHDRS clause.
3014 allocate_to_segment(String_list**, bool*);
3016 // Return the associated Output_section.
3018 get_output_section() const
3019 { return this->os_; }
3021 // Print for debugging.
3023 print(FILE* f) const
3025 fprintf(f, " marker for orphaned output section %s\n",
3030 Output_section* os_;
3033 // Set section addresses.
3036 Orphan_output_section::set_section_addresses(Symbol_table*, Layout*,
3037 uint64_t* dot_value,
3039 uint64_t* load_address)
3041 typedef std::list<Output_section::Input_section> Input_section_list;
3043 bool have_load_address = *load_address != *dot_value;
3045 uint64_t address = *dot_value;
3046 address = align_address(address, this->os_->addralign());
3048 // If input section sorting is requested via --section-ordering-file or
3049 // linker plugins, then do it here. This is important because we want
3050 // any sorting specified in the linker scripts, which will be done after
3051 // this, to take precedence. The final order of input sections is then
3052 // guaranteed to be according to the linker script specification.
3053 if (this->os_ != NULL
3054 && this->os_->input_section_order_specified())
3055 this->os_->sort_attached_input_sections();
3057 // For a relocatable link, all orphan sections are put at
3058 // address 0. In general we expect all sections to be at
3059 // address 0 for a relocatable link, but we permit the linker
3060 // script to override that for specific output sections.
3061 if (parameters->options().relocatable())
3065 have_load_address = false;
3068 if ((this->os_->flags() & elfcpp::SHF_ALLOC) != 0)
3070 this->os_->set_address(address);
3071 if (have_load_address)
3072 this->os_->set_load_address(align_address(*load_address,
3073 this->os_->addralign()));
3076 Input_section_list input_sections;
3077 address += this->os_->get_input_sections(address, "", &input_sections);
3079 for (Input_section_list::iterator p = input_sections.begin();
3080 p != input_sections.end();
3083 uint64_t addralign = p->addralign();
3084 if (!p->is_input_section())
3085 p->output_section_data()->finalize_data_size();
3086 uint64_t size = p->data_size();
3087 address = align_address(address, addralign);
3088 this->os_->add_script_input_section(*p);
3092 if (parameters->options().relocatable())
3094 // For a relocatable link, reset DOT_VALUE to 0.
3098 else if (this->os_ == NULL
3099 || (this->os_->flags() & elfcpp::SHF_TLS) == 0
3100 || this->os_->type() != elfcpp::SHT_NOBITS)
3102 // An SHF_TLS/SHT_NOBITS section does not take up any address space.
3103 if (!have_load_address)
3104 *load_address = address;
3106 *load_address += address - *dot_value;
3108 *dot_value = address;
3112 // Get the list of segments to use for an allocated section when using
3113 // a PHDRS clause. If this is an allocated section, return the
3114 // Output_section. We don't change the list of segments.
3117 Orphan_output_section::allocate_to_segment(String_list**, bool* orphan)
3119 if ((this->os_->flags() & elfcpp::SHF_ALLOC) == 0)
3125 // Class Phdrs_element. A program header from a PHDRS clause.
3130 Phdrs_element(const char* name, size_t namelen, unsigned int type,
3131 bool includes_filehdr, bool includes_phdrs,
3132 bool is_flags_valid, unsigned int flags,
3133 Expression* load_address)
3134 : name_(name, namelen), type_(type), includes_filehdr_(includes_filehdr),
3135 includes_phdrs_(includes_phdrs), is_flags_valid_(is_flags_valid),
3136 flags_(flags), load_address_(load_address), load_address_value_(0),
3140 // Return the name of this segment.
3143 { return this->name_; }
3145 // Return the type of the segment.
3148 { return this->type_; }
3150 // Whether to include the file header.
3152 includes_filehdr() const
3153 { return this->includes_filehdr_; }
3155 // Whether to include the program headers.
3157 includes_phdrs() const
3158 { return this->includes_phdrs_; }
3160 // Return whether there is a load address.
3162 has_load_address() const
3163 { return this->load_address_ != NULL; }
3165 // Evaluate the load address expression if there is one.
3167 eval_load_address(Symbol_table* symtab, Layout* layout)
3169 if (this->load_address_ != NULL)
3170 this->load_address_value_ = this->load_address_->eval(symtab, layout,
3174 // Return the load address.
3176 load_address() const
3178 gold_assert(this->load_address_ != NULL);
3179 return this->load_address_value_;
3182 // Create the segment.
3184 create_segment(Layout* layout)
3186 this->segment_ = layout->make_output_segment(this->type_, this->flags_);
3187 return this->segment_;
3190 // Return the segment.
3193 { return this->segment_; }
3195 // Release the segment.
3198 { this->segment_ = NULL; }
3200 // Set the segment flags if appropriate.
3202 set_flags_if_valid()
3204 if (this->is_flags_valid_)
3205 this->segment_->set_flags(this->flags_);
3208 // Print for debugging.
3213 // The name used in the script.
3215 // The type of the segment (PT_LOAD, etc.).
3217 // Whether this segment includes the file header.
3218 bool includes_filehdr_;
3219 // Whether this segment includes the section headers.
3220 bool includes_phdrs_;
3221 // Whether the flags were explicitly specified.
3222 bool is_flags_valid_;
3223 // The flags for this segment (PF_R, etc.) if specified.
3224 unsigned int flags_;
3225 // The expression for the load address for this segment. This may
3227 Expression* load_address_;
3228 // The actual load address from evaluating the expression.
3229 uint64_t load_address_value_;
3230 // The segment itself.
3231 Output_segment* segment_;
3234 // Print for debugging.
3237 Phdrs_element::print(FILE* f) const
3239 fprintf(f, " %s 0x%x", this->name_.c_str(), this->type_);
3240 if (this->includes_filehdr_)
3241 fprintf(f, " FILEHDR");
3242 if (this->includes_phdrs_)
3243 fprintf(f, " PHDRS");
3244 if (this->is_flags_valid_)
3245 fprintf(f, " FLAGS(%u)", this->flags_);
3246 if (this->load_address_ != NULL)
3249 this->load_address_->print(f);
3255 // Add a memory region.
3258 Script_sections::add_memory_region(const char* name, size_t namelen,
3259 unsigned int attributes,
3260 Expression* start, Expression* length)
3262 if (this->memory_regions_ == NULL)
3263 this->memory_regions_ = new Memory_regions();
3264 else if (this->find_memory_region(name, namelen))
3266 gold_error(_("region '%.*s' already defined"), static_cast<int>(namelen),
3268 // FIXME: Add a GOLD extension to allow multiple regions with the same
3269 // name. This would amount to a single region covering disjoint blocks
3270 // of memory, which is useful for embedded devices.
3273 // FIXME: Check the length and start values. Currently we allow
3274 // non-constant expressions for these values, whereas LD does not.
3276 // FIXME: Add a GOLD extension to allow NEGATIVE LENGTHS. This would
3277 // describe a region that packs from the end address going down, rather
3278 // than the start address going up. This would be useful for embedded
3281 this->memory_regions_->push_back(new Memory_region(name, namelen, attributes,
3285 // Find a memory region.
3288 Script_sections::find_memory_region(const char* name, size_t namelen)
3290 if (this->memory_regions_ == NULL)
3293 for (Memory_regions::const_iterator m = this->memory_regions_->begin();
3294 m != this->memory_regions_->end();
3296 if ((*m)->name_match(name, namelen))
3302 // Find a memory region's origin.
3305 Script_sections::find_memory_region_origin(const char* name, size_t namelen)
3307 Memory_region* mr = find_memory_region(name, namelen);
3311 return mr->start_address();
3314 // Find a memory region's length.
3317 Script_sections::find_memory_region_length(const char* name, size_t namelen)
3319 Memory_region* mr = find_memory_region(name, namelen);
3323 return mr->length();
3326 // Set the memory region to use for the current section.
3329 Script_sections::set_memory_region(Memory_region* mr, bool set_vma)
3331 gold_assert(!this->sections_elements_->empty());
3332 this->sections_elements_->back()->set_memory_region(mr, set_vma);
3335 // Class Script_sections.
3337 Script_sections::Script_sections()
3338 : saw_sections_clause_(false),
3339 in_sections_clause_(false),
3340 sections_elements_(NULL),
3341 output_section_(NULL),
3342 memory_regions_(NULL),
3343 phdrs_elements_(NULL),
3344 orphan_section_placement_(NULL),
3345 data_segment_align_start_(),
3346 saw_data_segment_align_(false),
3347 saw_relro_end_(false),
3348 saw_segment_start_expression_(false),
3349 segments_created_(false)
3353 // Start a SECTIONS clause.
3356 Script_sections::start_sections()
3358 gold_assert(!this->in_sections_clause_ && this->output_section_ == NULL);
3359 this->saw_sections_clause_ = true;
3360 this->in_sections_clause_ = true;
3361 if (this->sections_elements_ == NULL)
3362 this->sections_elements_ = new Sections_elements;
3365 // Finish a SECTIONS clause.
3368 Script_sections::finish_sections()
3370 gold_assert(this->in_sections_clause_ && this->output_section_ == NULL);
3371 this->in_sections_clause_ = false;
3374 // Add a symbol to be defined.
3377 Script_sections::add_symbol_assignment(const char* name, size_t length,
3378 Expression* val, bool provide,
3381 if (this->output_section_ != NULL)
3382 this->output_section_->add_symbol_assignment(name, length, val,
3386 Sections_element* p = new Sections_element_assignment(name, length,
3389 this->sections_elements_->push_back(p);
3393 // Add an assignment to the special dot symbol.
3396 Script_sections::add_dot_assignment(Expression* val)
3398 if (this->output_section_ != NULL)
3399 this->output_section_->add_dot_assignment(val);
3402 // The GNU linker permits assignments to . to appears outside of
3403 // a SECTIONS clause, and treats it as appearing inside, so
3404 // sections_elements_ may be NULL here.
3405 if (this->sections_elements_ == NULL)
3407 this->sections_elements_ = new Sections_elements;
3408 this->saw_sections_clause_ = true;
3411 Sections_element* p = new Sections_element_dot_assignment(val);
3412 this->sections_elements_->push_back(p);
3416 // Add an assertion.
3419 Script_sections::add_assertion(Expression* check, const char* message,
3422 if (this->output_section_ != NULL)
3423 this->output_section_->add_assertion(check, message, messagelen);
3426 Sections_element* p = new Sections_element_assertion(check, message,
3428 this->sections_elements_->push_back(p);
3432 // Start processing entries for an output section.
3435 Script_sections::start_output_section(
3438 const Parser_output_section_header* header)
3440 Output_section_definition* posd = new Output_section_definition(name,
3443 this->sections_elements_->push_back(posd);
3444 gold_assert(this->output_section_ == NULL);
3445 this->output_section_ = posd;
3448 // Stop processing entries for an output section.
3451 Script_sections::finish_output_section(
3452 const Parser_output_section_trailer* trailer)
3454 gold_assert(this->output_section_ != NULL);
3455 this->output_section_->finish(trailer);
3456 this->output_section_ = NULL;
3459 // Add a data item to the current output section.
3462 Script_sections::add_data(int size, bool is_signed, Expression* val)
3464 gold_assert(this->output_section_ != NULL);
3465 this->output_section_->add_data(size, is_signed, val);
3468 // Add a fill value setting to the current output section.
3471 Script_sections::add_fill(Expression* val)
3473 gold_assert(this->output_section_ != NULL);
3474 this->output_section_->add_fill(val);
3477 // Add an input section specification to the current output section.
3480 Script_sections::add_input_section(const Input_section_spec* spec, bool keep)
3482 gold_assert(this->output_section_ != NULL);
3483 this->output_section_->add_input_section(spec, keep);
3486 // This is called when we see DATA_SEGMENT_ALIGN. It means that any
3487 // subsequent output sections may be relro.
3490 Script_sections::data_segment_align()
3492 if (this->saw_data_segment_align_)
3493 gold_error(_("DATA_SEGMENT_ALIGN may only appear once in a linker script"));
3494 gold_assert(!this->sections_elements_->empty());
3495 Sections_elements::iterator p = this->sections_elements_->end();
3497 this->data_segment_align_start_ = p;
3498 this->saw_data_segment_align_ = true;
3501 // This is called when we see DATA_SEGMENT_RELRO_END. It means that
3502 // any output sections seen since DATA_SEGMENT_ALIGN are relro.
3505 Script_sections::data_segment_relro_end()
3507 if (this->saw_relro_end_)
3508 gold_error(_("DATA_SEGMENT_RELRO_END may only appear once "
3509 "in a linker script"));
3510 this->saw_relro_end_ = true;
3512 if (!this->saw_data_segment_align_)
3513 gold_error(_("DATA_SEGMENT_RELRO_END must follow DATA_SEGMENT_ALIGN"));
3516 Sections_elements::iterator p = this->data_segment_align_start_;
3517 for (++p; p != this->sections_elements_->end(); ++p)
3518 (*p)->set_is_relro();
3522 // Create any required sections.
3525 Script_sections::create_sections(Layout* layout)
3527 if (!this->saw_sections_clause_)
3529 for (Sections_elements::iterator p = this->sections_elements_->begin();
3530 p != this->sections_elements_->end();
3532 (*p)->create_sections(layout);
3535 // Add any symbols we are defining to the symbol table.
3538 Script_sections::add_symbols_to_table(Symbol_table* symtab)
3540 if (!this->saw_sections_clause_)
3542 for (Sections_elements::iterator p = this->sections_elements_->begin();
3543 p != this->sections_elements_->end();
3545 (*p)->add_symbols_to_table(symtab);
3548 // Finalize symbols and check assertions.
3551 Script_sections::finalize_symbols(Symbol_table* symtab, const Layout* layout)
3553 if (!this->saw_sections_clause_)
3555 uint64_t dot_value = 0;
3556 for (Sections_elements::iterator p = this->sections_elements_->begin();
3557 p != this->sections_elements_->end();
3559 (*p)->finalize_symbols(symtab, layout, &dot_value);
3562 // Return the name of the output section to use for an input file name
3563 // and section name.
3566 Script_sections::output_section_name(
3567 const char* file_name,
3568 const char* section_name,
3569 Output_section*** output_section_slot,
3570 Script_sections::Section_type* psection_type,
3573 for (Sections_elements::const_iterator p = this->sections_elements_->begin();
3574 p != this->sections_elements_->end();
3577 const char* ret = (*p)->output_section_name(file_name, section_name,
3578 output_section_slot,
3579 psection_type, keep);
3583 // The special name /DISCARD/ means that the input section
3584 // should be discarded.
3585 if (strcmp(ret, "/DISCARD/") == 0)
3587 *output_section_slot = NULL;
3588 *psection_type = Script_sections::ST_NONE;
3595 // We have an orphan section.
3596 *output_section_slot = NULL;
3597 *psection_type = Script_sections::ST_NONE;
3600 General_options::Orphan_handling orphan_handling =
3601 parameters->options().orphan_handling_enum();
3602 if (orphan_handling == General_options::ORPHAN_DISCARD)
3604 if (orphan_handling == General_options::ORPHAN_ERROR)
3606 if (file_name == NULL)
3607 gold_error(_("unplaced orphan section '%s'"), section_name);
3609 gold_error(_("unplaced orphan section '%s' from '%s'"),
3610 section_name, file_name);
3613 if (orphan_handling == General_options::ORPHAN_WARN)
3615 if (file_name == NULL)
3616 gold_warning(_("orphan section '%s' is being placed in section '%s'"),
3617 section_name, section_name);
3619 gold_warning(_("orphan section '%s' from '%s' is being placed "
3621 section_name, file_name, section_name);
3624 // If we couldn't find a mapping for the name, the output section
3625 // gets the name of the input section.
3626 return section_name;
3629 // Place a marker for an orphan output section into the SECTIONS
3633 Script_sections::place_orphan(Output_section* os)
3635 Orphan_section_placement* osp = this->orphan_section_placement_;
3638 // Initialize the Orphan_section_placement structure.
3639 osp = new Orphan_section_placement();
3640 for (Sections_elements::iterator p = this->sections_elements_->begin();
3641 p != this->sections_elements_->end();
3643 (*p)->orphan_section_init(osp, p);
3644 gold_assert(!this->sections_elements_->empty());
3645 Sections_elements::iterator last = this->sections_elements_->end();
3647 osp->last_init(last);
3648 this->orphan_section_placement_ = osp;
3651 Orphan_output_section* orphan = new Orphan_output_section(os);
3653 // Look for where to put ORPHAN.
3654 Sections_elements::iterator* where;
3655 if (osp->find_place(os, &where))
3657 if ((**where)->is_relro())
3660 os->clear_is_relro();
3662 // We want to insert ORPHAN after *WHERE, and then update *WHERE
3663 // so that the next one goes after this one.
3664 Sections_elements::iterator p = *where;
3665 gold_assert(p != this->sections_elements_->end());
3667 *where = this->sections_elements_->insert(p, orphan);
3671 os->clear_is_relro();
3672 // We don't have a place to put this orphan section. Put it,
3673 // and all other sections like it, at the end, but before the
3674 // sections which always come at the end.
3675 Sections_elements::iterator last = osp->last_place();
3676 *where = this->sections_elements_->insert(last, orphan);
3679 if ((os->flags() & elfcpp::SHF_ALLOC) != 0)
3680 osp->update_last_alloc(*where);
3683 // Set the addresses of all the output sections. Walk through all the
3684 // elements, tracking the dot symbol. Apply assignments which set
3685 // absolute symbol values, in case they are used when setting dot.
3686 // Fill in data statement values. As we find output sections, set the
3687 // address, set the address of all associated input sections, and
3688 // update dot. Return the segment which should hold the file header
3689 // and segment headers, if any.
3692 Script_sections::set_section_addresses(Symbol_table* symtab, Layout* layout)
3694 gold_assert(this->saw_sections_clause_);
3696 // Implement ONLY_IF_RO/ONLY_IF_RW constraints. These are a pain
3697 // for our representation.
3698 for (Sections_elements::iterator p = this->sections_elements_->begin();
3699 p != this->sections_elements_->end();
3702 Output_section_definition* posd;
3703 Section_constraint failed_constraint = (*p)->check_constraint(&posd);
3704 if (failed_constraint != CONSTRAINT_NONE)
3706 Sections_elements::iterator q;
3707 for (q = this->sections_elements_->begin();
3708 q != this->sections_elements_->end();
3713 if ((*q)->alternate_constraint(posd, failed_constraint))
3718 if (q == this->sections_elements_->end())
3719 gold_error(_("no matching section constraint"));
3723 // Force the alignment of the first TLS section to be the maximum
3724 // alignment of all TLS sections.
3725 Output_section* first_tls = NULL;
3726 uint64_t tls_align = 0;
3727 for (Sections_elements::const_iterator p = this->sections_elements_->begin();
3728 p != this->sections_elements_->end();
3731 Output_section* os = (*p)->get_output_section();
3732 if (os != NULL && (os->flags() & elfcpp::SHF_TLS) != 0)
3734 if (first_tls == NULL)
3736 if (os->addralign() > tls_align)
3737 tls_align = os->addralign();
3740 if (first_tls != NULL)
3741 first_tls->set_addralign(tls_align);
3743 // For a relocatable link, we implicitly set dot to zero.
3744 uint64_t dot_value = 0;
3745 uint64_t dot_alignment = 0;
3746 uint64_t load_address = 0;
3748 // Check to see if we want to use any of -Ttext, -Tdata and -Tbss options
3749 // to set section addresses. If the script has any SEGMENT_START
3750 // expression, we do not set the section addresses.
3751 bool use_tsection_options =
3752 (!this->saw_segment_start_expression_
3753 && (parameters->options().user_set_Ttext()
3754 || parameters->options().user_set_Tdata()
3755 || parameters->options().user_set_Tbss()));
3757 for (Sections_elements::iterator p = this->sections_elements_->begin();
3758 p != this->sections_elements_->end();
3761 Output_section* os = (*p)->get_output_section();
3763 // Handle -Ttext, -Tdata and -Tbss options. We do this by looking for
3764 // the special sections by names and doing dot assignments.
3765 if (use_tsection_options
3767 && (os->flags() & elfcpp::SHF_ALLOC) != 0)
3769 uint64_t new_dot_value = dot_value;
3771 if (parameters->options().user_set_Ttext()
3772 && strcmp(os->name(), ".text") == 0)
3773 new_dot_value = parameters->options().Ttext();
3774 else if (parameters->options().user_set_Tdata()
3775 && strcmp(os->name(), ".data") == 0)
3776 new_dot_value = parameters->options().Tdata();
3777 else if (parameters->options().user_set_Tbss()
3778 && strcmp(os->name(), ".bss") == 0)
3779 new_dot_value = parameters->options().Tbss();
3781 // Update dot and load address if necessary.
3782 if (new_dot_value < dot_value)
3783 gold_error(_("dot may not move backward"));
3784 else if (new_dot_value != dot_value)
3786 dot_value = new_dot_value;
3787 load_address = new_dot_value;
3791 (*p)->set_section_addresses(symtab, layout, &dot_value, &dot_alignment,
3795 if (this->phdrs_elements_ != NULL)
3797 for (Phdrs_elements::iterator p = this->phdrs_elements_->begin();
3798 p != this->phdrs_elements_->end();
3800 (*p)->eval_load_address(symtab, layout);
3803 return this->create_segments(layout, dot_alignment);
3806 // Sort the sections in order to put them into segments.
3808 class Sort_output_sections
3811 Sort_output_sections(const Script_sections::Sections_elements* elements)
3812 : elements_(elements)
3816 operator()(const Output_section* os1, const Output_section* os2) const;
3820 script_compare(const Output_section* os1, const Output_section* os2) const;
3823 const Script_sections::Sections_elements* elements_;
3827 Sort_output_sections::operator()(const Output_section* os1,
3828 const Output_section* os2) const
3830 // Sort first by the load address.
3831 uint64_t lma1 = (os1->has_load_address()
3832 ? os1->load_address()
3834 uint64_t lma2 = (os2->has_load_address()
3835 ? os2->load_address()
3840 // Then sort by the virtual address.
3841 if (os1->address() != os2->address())
3842 return os1->address() < os2->address();
3844 // If the linker script says which of these sections is first, go
3845 // with what it says.
3846 int i = this->script_compare(os1, os2);
3850 // Sort PROGBITS before NOBITS.
3851 bool nobits1 = os1->type() == elfcpp::SHT_NOBITS;
3852 bool nobits2 = os2->type() == elfcpp::SHT_NOBITS;
3853 if (nobits1 != nobits2)
3856 // Sort PROGBITS TLS sections to the end, NOBITS TLS sections to the
3858 bool tls1 = (os1->flags() & elfcpp::SHF_TLS) != 0;
3859 bool tls2 = (os2->flags() & elfcpp::SHF_TLS) != 0;
3861 return nobits1 ? tls1 : tls2;
3863 // Sort non-NOLOAD before NOLOAD.
3864 if (os1->is_noload() && !os2->is_noload())
3866 if (!os1->is_noload() && os2->is_noload())
3869 // The sections seem practically identical. Sort by name to get a
3871 return os1->name() < os2->name();
3874 // Return -1 if OS1 comes before OS2 in ELEMENTS_, 1 if comes after, 0
3875 // if either OS1 or OS2 is not mentioned. This ensures that we keep
3876 // empty sections in the order in which they appear in a linker
3880 Sort_output_sections::script_compare(const Output_section* os1,
3881 const Output_section* os2) const
3883 if (this->elements_ == NULL)
3886 bool found_os1 = false;
3887 bool found_os2 = false;
3888 for (Script_sections::Sections_elements::const_iterator
3889 p = this->elements_->begin();
3890 p != this->elements_->end();
3893 if (os2 == (*p)->get_output_section())
3899 else if (os1 == (*p)->get_output_section())
3910 // Return whether OS is a BSS section. This is a SHT_NOBITS section.
3911 // We treat a section with the SHF_TLS flag set as taking up space
3912 // even if it is SHT_NOBITS (this is true of .tbss), as we allocate
3913 // space for them in the file.
3916 Script_sections::is_bss_section(const Output_section* os)
3918 return (os->type() == elfcpp::SHT_NOBITS
3919 && (os->flags() & elfcpp::SHF_TLS) == 0);
3922 // Return the size taken by the file header and the program headers.
3925 Script_sections::total_header_size(Layout* layout) const
3927 size_t segment_count = layout->segment_count();
3928 size_t file_header_size;
3929 size_t segment_headers_size;
3930 if (parameters->target().get_size() == 32)
3932 file_header_size = elfcpp::Elf_sizes<32>::ehdr_size;
3933 segment_headers_size = segment_count * elfcpp::Elf_sizes<32>::phdr_size;
3935 else if (parameters->target().get_size() == 64)
3937 file_header_size = elfcpp::Elf_sizes<64>::ehdr_size;
3938 segment_headers_size = segment_count * elfcpp::Elf_sizes<64>::phdr_size;
3943 return file_header_size + segment_headers_size;
3946 // Return the amount we have to subtract from the LMA to accommodate
3947 // headers of the given size. The complication is that the file
3948 // header have to be at the start of a page, as otherwise it will not
3949 // be at the start of the file.
3952 Script_sections::header_size_adjustment(uint64_t lma,
3953 size_t sizeof_headers) const
3955 const uint64_t abi_pagesize = parameters->target().abi_pagesize();
3956 uint64_t hdr_lma = lma - sizeof_headers;
3957 hdr_lma &= ~(abi_pagesize - 1);
3958 return lma - hdr_lma;
3961 // Create the PT_LOAD segments when using a SECTIONS clause. Returns
3962 // the segment which should hold the file header and segment headers,
3966 Script_sections::create_segments(Layout* layout, uint64_t dot_alignment)
3968 gold_assert(this->saw_sections_clause_);
3970 if (parameters->options().relocatable())
3973 if (this->saw_phdrs_clause())
3974 return create_segments_from_phdrs_clause(layout, dot_alignment);
3976 Layout::Section_list sections;
3977 layout->get_allocated_sections(§ions);
3979 // Sort the sections by address.
3980 std::stable_sort(sections.begin(), sections.end(),
3981 Sort_output_sections(this->sections_elements_));
3983 this->create_note_and_tls_segments(layout, §ions);
3985 // Walk through the sections adding them to PT_LOAD segments.
3986 const uint64_t abi_pagesize = parameters->target().abi_pagesize();
3987 Output_segment* first_seg = NULL;
3988 Output_segment* current_seg = NULL;
3989 bool is_current_seg_readonly = true;
3990 uint64_t last_vma = 0;
3991 uint64_t last_lma = 0;
3992 uint64_t last_size = 0;
3993 bool in_bss = false;
3994 for (Layout::Section_list::iterator p = sections.begin();
3995 p != sections.end();
3998 const uint64_t vma = (*p)->address();
3999 const uint64_t lma = ((*p)->has_load_address()
4000 ? (*p)->load_address()
4002 const uint64_t size = (*p)->current_data_size();
4004 bool need_new_segment;
4005 if (current_seg == NULL)
4006 need_new_segment = true;
4007 else if (lma - vma != last_lma - last_vma)
4009 // This section has a different LMA relationship than the
4010 // last one; we need a new segment.
4011 need_new_segment = true;
4013 else if (align_address(last_lma + last_size, abi_pagesize)
4014 < align_address(lma, abi_pagesize))
4016 // Putting this section in the segment would require
4018 need_new_segment = true;
4020 else if (in_bss && !is_bss_section(*p))
4022 // A non-BSS section can not follow a BSS section in the
4024 need_new_segment = true;
4026 else if (is_current_seg_readonly
4027 && ((*p)->flags() & elfcpp::SHF_WRITE) != 0
4028 && !parameters->options().omagic())
4030 // Don't put a writable section in the same segment as a
4031 // non-writable section.
4032 need_new_segment = true;
4036 // Otherwise, reuse the existing segment.
4037 need_new_segment = false;
4040 elfcpp::Elf_Word seg_flags =
4041 Layout::section_flags_to_segment((*p)->flags());
4043 if (need_new_segment)
4045 current_seg = layout->make_output_segment(elfcpp::PT_LOAD,
4047 current_seg->set_addresses(vma, lma);
4048 current_seg->set_minimum_p_align(dot_alignment);
4049 if (first_seg == NULL)
4050 first_seg = current_seg;
4051 is_current_seg_readonly = true;
4055 current_seg->add_output_section_to_load(layout, *p, seg_flags);
4057 if (((*p)->flags() & elfcpp::SHF_WRITE) != 0)
4058 is_current_seg_readonly = false;
4060 if (is_bss_section(*p) && size > 0)
4068 // An ELF program should work even if the program headers are not in
4069 // a PT_LOAD segment. However, it appears that the Linux kernel
4070 // does not set the AT_PHDR auxiliary entry in that case. It sets
4071 // the load address to p_vaddr - p_offset of the first PT_LOAD
4072 // segment. It then sets AT_PHDR to the load address plus the
4073 // offset to the program headers, e_phoff in the file header. This
4074 // fails when the program headers appear in the file before the
4075 // first PT_LOAD segment. Therefore, we always create a PT_LOAD
4076 // segment to hold the file header and the program headers. This is
4077 // effectively what the GNU linker does, and it is slightly more
4078 // efficient in any case. We try to use the first PT_LOAD segment
4079 // if we can, otherwise we make a new one.
4081 if (first_seg == NULL)
4084 // -n or -N mean that the program is not demand paged and there is
4085 // no need to put the program headers in a PT_LOAD segment.
4086 if (parameters->options().nmagic() || parameters->options().omagic())
4089 size_t sizeof_headers = this->total_header_size(layout);
4091 uint64_t vma = first_seg->vaddr();
4092 uint64_t lma = first_seg->paddr();
4094 uint64_t subtract = this->header_size_adjustment(lma, sizeof_headers);
4096 if ((lma & (abi_pagesize - 1)) >= sizeof_headers)
4098 first_seg->set_addresses(vma - subtract, lma - subtract);
4102 // If there is no room to squeeze in the headers, then punt. The
4103 // resulting executable probably won't run on GNU/Linux, but we
4104 // trust that the user knows what they are doing.
4105 if (lma < subtract || vma < subtract)
4108 // If memory regions have been specified and the address range
4109 // we are about to use is not contained within any region then
4110 // issue a warning message about the segment we are going to
4111 // create. It will be outside of any region and so possibly
4112 // using non-existent or protected memory. We test LMA rather
4113 // than VMA since we assume that the headers will never be
4115 if (this->memory_regions_ != NULL
4116 && !this->block_in_region (NULL, layout, lma - subtract, subtract))
4117 gold_warning(_("creating a segment to contain the file and program"
4118 " headers outside of any MEMORY region"));
4120 Output_segment* load_seg = layout->make_output_segment(elfcpp::PT_LOAD,
4122 load_seg->set_addresses(vma - subtract, lma - subtract);
4127 // Create a PT_NOTE segment for each SHT_NOTE section and a PT_TLS
4128 // segment if there are any SHT_TLS sections.
4131 Script_sections::create_note_and_tls_segments(
4133 const Layout::Section_list* sections)
4135 gold_assert(!this->saw_phdrs_clause());
4137 bool saw_tls = false;
4138 for (Layout::Section_list::const_iterator p = sections->begin();
4139 p != sections->end();
4142 if ((*p)->type() == elfcpp::SHT_NOTE)
4144 elfcpp::Elf_Word seg_flags =
4145 Layout::section_flags_to_segment((*p)->flags());
4146 Output_segment* oseg = layout->make_output_segment(elfcpp::PT_NOTE,
4148 oseg->add_output_section_to_nonload(*p, seg_flags);
4150 // Incorporate any subsequent SHT_NOTE sections, in the
4151 // hopes that the script is sensible.
4152 Layout::Section_list::const_iterator pnext = p + 1;
4153 while (pnext != sections->end()
4154 && (*pnext)->type() == elfcpp::SHT_NOTE)
4156 seg_flags = Layout::section_flags_to_segment((*pnext)->flags());
4157 oseg->add_output_section_to_nonload(*pnext, seg_flags);
4163 if (((*p)->flags() & elfcpp::SHF_TLS) != 0)
4166 gold_error(_("TLS sections are not adjacent"));
4168 elfcpp::Elf_Word seg_flags =
4169 Layout::section_flags_to_segment((*p)->flags());
4170 Output_segment* oseg = layout->make_output_segment(elfcpp::PT_TLS,
4172 oseg->add_output_section_to_nonload(*p, seg_flags);
4174 Layout::Section_list::const_iterator pnext = p + 1;
4175 while (pnext != sections->end()
4176 && ((*pnext)->flags() & elfcpp::SHF_TLS) != 0)
4178 seg_flags = Layout::section_flags_to_segment((*pnext)->flags());
4179 oseg->add_output_section_to_nonload(*pnext, seg_flags);
4187 // If we see a section named .interp then put the .interp section
4188 // in a PT_INTERP segment.
4189 // This is for GNU ld compatibility.
4190 if (strcmp((*p)->name(), ".interp") == 0)
4192 elfcpp::Elf_Word seg_flags =
4193 Layout::section_flags_to_segment((*p)->flags());
4194 Output_segment* oseg = layout->make_output_segment(elfcpp::PT_INTERP,
4196 oseg->add_output_section_to_nonload(*p, seg_flags);
4200 this->segments_created_ = true;
4203 // Add a program header. The PHDRS clause is syntactically distinct
4204 // from the SECTIONS clause, but we implement it with the SECTIONS
4205 // support because PHDRS is useless if there is no SECTIONS clause.
4208 Script_sections::add_phdr(const char* name, size_t namelen, unsigned int type,
4209 bool includes_filehdr, bool includes_phdrs,
4210 bool is_flags_valid, unsigned int flags,
4211 Expression* load_address)
4213 if (this->phdrs_elements_ == NULL)
4214 this->phdrs_elements_ = new Phdrs_elements();
4215 this->phdrs_elements_->push_back(new Phdrs_element(name, namelen, type,
4218 is_flags_valid, flags,
4222 // Return the number of segments we expect to create based on the
4223 // SECTIONS clause. This is used to implement SIZEOF_HEADERS.
4226 Script_sections::expected_segment_count(const Layout* layout) const
4228 // If we've already created the segments, we won't be adding any more.
4229 if (this->segments_created_)
4232 if (this->saw_phdrs_clause())
4233 return this->phdrs_elements_->size();
4235 Layout::Section_list sections;
4236 layout->get_allocated_sections(§ions);
4238 // We assume that we will need two PT_LOAD segments.
4241 bool saw_note = false;
4242 bool saw_tls = false;
4243 bool saw_interp = false;
4244 for (Layout::Section_list::const_iterator p = sections.begin();
4245 p != sections.end();
4248 if ((*p)->type() == elfcpp::SHT_NOTE)
4250 // Assume that all note sections will fit into a single
4258 else if (((*p)->flags() & elfcpp::SHF_TLS) != 0)
4260 // There can only be one PT_TLS segment.
4267 else if (strcmp((*p)->name(), ".interp") == 0)
4269 // There can only be one PT_INTERP segment.
4281 // Create the segments from a PHDRS clause. Return the segment which
4282 // should hold the file header and program headers, if any.
4285 Script_sections::create_segments_from_phdrs_clause(Layout* layout,
4286 uint64_t dot_alignment)
4288 this->attach_sections_using_phdrs_clause(layout);
4289 return this->set_phdrs_clause_addresses(layout, dot_alignment);
4292 // Create the segments from the PHDRS clause, and put the output
4293 // sections in them.
4296 Script_sections::attach_sections_using_phdrs_clause(Layout* layout)
4298 typedef std::map<std::string, Output_segment*> Name_to_segment;
4299 Name_to_segment name_to_segment;
4300 for (Phdrs_elements::const_iterator p = this->phdrs_elements_->begin();
4301 p != this->phdrs_elements_->end();
4303 name_to_segment[(*p)->name()] = (*p)->create_segment(layout);
4304 this->segments_created_ = true;
4306 // Walk through the output sections and attach them to segments.
4307 // Output sections in the script which do not list segments are
4308 // attached to the same set of segments as the immediately preceding
4311 String_list* phdr_names = NULL;
4312 bool load_segments_only = false;
4313 for (Sections_elements::const_iterator p = this->sections_elements_->begin();
4314 p != this->sections_elements_->end();
4318 String_list* old_phdr_names = phdr_names;
4319 Output_section* os = (*p)->allocate_to_segment(&phdr_names, &is_orphan);
4323 elfcpp::Elf_Word seg_flags =
4324 Layout::section_flags_to_segment(os->flags());
4326 if (phdr_names == NULL)
4328 // Don't worry about empty orphan sections.
4329 if (is_orphan && os->current_data_size() > 0)
4330 gold_error(_("allocated section %s not in any segment"),
4333 // To avoid later crashes drop this section into the first
4335 for (Phdrs_elements::const_iterator ppe =
4336 this->phdrs_elements_->begin();
4337 ppe != this->phdrs_elements_->end();
4340 Output_segment* oseg = (*ppe)->segment();
4341 if (oseg->type() == elfcpp::PT_LOAD)
4343 oseg->add_output_section_to_load(layout, os, seg_flags);
4351 // We see a list of segments names. Disable PT_LOAD segment only
4353 if (old_phdr_names != phdr_names)
4354 load_segments_only = false;
4356 // If this is an orphan section--one that was not explicitly
4357 // mentioned in the linker script--then it should not inherit
4358 // any segment type other than PT_LOAD. Otherwise, e.g., the
4359 // PT_INTERP segment will pick up following orphan sections,
4360 // which does not make sense. If this is not an orphan section,
4361 // we trust the linker script.
4364 // Enable PT_LOAD segments only filtering until we see another
4365 // list of segment names.
4366 load_segments_only = true;
4369 bool in_load_segment = false;
4370 for (String_list::const_iterator q = phdr_names->begin();
4371 q != phdr_names->end();
4374 Name_to_segment::const_iterator r = name_to_segment.find(*q);
4375 if (r == name_to_segment.end())
4376 gold_error(_("no segment %s"), q->c_str());
4379 if (load_segments_only
4380 && r->second->type() != elfcpp::PT_LOAD)
4383 if (r->second->type() != elfcpp::PT_LOAD)
4384 r->second->add_output_section_to_nonload(os, seg_flags);
4387 r->second->add_output_section_to_load(layout, os, seg_flags);
4388 if (in_load_segment)
4389 gold_error(_("section in two PT_LOAD segments"));
4390 in_load_segment = true;
4395 if (!in_load_segment)
4396 gold_error(_("allocated section not in any PT_LOAD segment"));
4400 // Set the addresses for segments created from a PHDRS clause. Return
4401 // the segment which should hold the file header and program headers,
4405 Script_sections::set_phdrs_clause_addresses(Layout* layout,
4406 uint64_t dot_alignment)
4408 Output_segment* load_seg = NULL;
4409 for (Phdrs_elements::const_iterator p = this->phdrs_elements_->begin();
4410 p != this->phdrs_elements_->end();
4413 // Note that we have to set the flags after adding the output
4414 // sections to the segment, as adding an output segment can
4415 // change the flags.
4416 (*p)->set_flags_if_valid();
4418 Output_segment* oseg = (*p)->segment();
4420 if (oseg->type() != elfcpp::PT_LOAD)
4422 // The addresses of non-PT_LOAD segments are set from the
4423 // PT_LOAD segments.
4424 if ((*p)->has_load_address())
4425 gold_error(_("may only specify load address for PT_LOAD segment"));
4429 oseg->set_minimum_p_align(dot_alignment);
4431 // The output sections should have addresses from the SECTIONS
4432 // clause. The addresses don't have to be in order, so find the
4433 // one with the lowest load address. Use that to set the
4434 // address of the segment.
4436 Output_section* osec = oseg->section_with_lowest_load_address();
4439 oseg->set_addresses(0, 0);
4443 uint64_t vma = osec->address();
4444 uint64_t lma = osec->has_load_address() ? osec->load_address() : vma;
4446 // Override the load address of the section with the load
4447 // address specified for the segment.
4448 if ((*p)->has_load_address())
4450 if (osec->has_load_address())
4451 gold_warning(_("PHDRS load address overrides "
4452 "section %s load address"),
4455 lma = (*p)->load_address();
4458 bool headers = (*p)->includes_filehdr() && (*p)->includes_phdrs();
4459 if (!headers && ((*p)->includes_filehdr() || (*p)->includes_phdrs()))
4461 // We could support this if we wanted to.
4462 gold_error(_("using only one of FILEHDR and PHDRS is "
4463 "not currently supported"));
4467 size_t sizeof_headers = this->total_header_size(layout);
4468 uint64_t subtract = this->header_size_adjustment(lma,
4470 if (lma >= subtract && vma >= subtract)
4477 gold_error(_("sections loaded on first page without room "
4478 "for file and program headers "
4479 "are not supported"));
4482 if (load_seg != NULL)
4483 gold_error(_("using FILEHDR and PHDRS on more than one "
4484 "PT_LOAD segment is not currently supported"));
4488 oseg->set_addresses(vma, lma);
4494 // Add the file header and segment headers to non-load segments
4495 // specified in the PHDRS clause.
4498 Script_sections::put_headers_in_phdrs(Output_data* file_header,
4499 Output_data* segment_headers)
4501 gold_assert(this->saw_phdrs_clause());
4502 for (Phdrs_elements::iterator p = this->phdrs_elements_->begin();
4503 p != this->phdrs_elements_->end();
4506 if ((*p)->type() != elfcpp::PT_LOAD)
4508 if ((*p)->includes_phdrs())
4509 (*p)->segment()->add_initial_output_data(segment_headers);
4510 if ((*p)->includes_filehdr())
4511 (*p)->segment()->add_initial_output_data(file_header);
4516 // Look for an output section by name and return the address, the load
4517 // address, the alignment, and the size. This is used when an
4518 // expression refers to an output section which was not actually
4519 // created. This returns true if the section was found, false
4523 Script_sections::get_output_section_info(const char* name, uint64_t* address,
4524 uint64_t* load_address,
4525 uint64_t* addralign,
4526 uint64_t* size) const
4528 if (!this->saw_sections_clause_)
4530 for (Sections_elements::const_iterator p = this->sections_elements_->begin();
4531 p != this->sections_elements_->end();
4533 if ((*p)->get_output_section_info(name, address, load_address, addralign,
4539 // Release all Output_segments. This remove all pointers to all
4543 Script_sections::release_segments()
4545 if (this->saw_phdrs_clause())
4547 for (Phdrs_elements::const_iterator p = this->phdrs_elements_->begin();
4548 p != this->phdrs_elements_->end();
4550 (*p)->release_segment();
4552 this->segments_created_ = false;
4555 // Print the SECTIONS clause to F for debugging.
4558 Script_sections::print(FILE* f) const
4560 if (this->phdrs_elements_ != NULL)
4562 fprintf(f, "PHDRS {\n");
4563 for (Phdrs_elements::const_iterator p = this->phdrs_elements_->begin();
4564 p != this->phdrs_elements_->end();
4570 if (this->memory_regions_ != NULL)
4572 fprintf(f, "MEMORY {\n");
4573 for (Memory_regions::const_iterator m = this->memory_regions_->begin();
4574 m != this->memory_regions_->end();
4580 if (!this->saw_sections_clause_)
4583 fprintf(f, "SECTIONS {\n");
4585 for (Sections_elements::const_iterator p = this->sections_elements_->begin();
4586 p != this->sections_elements_->end();
4593 } // End namespace gold.