1 // dwarf_reader.h -- parse dwarf2/3 debug information for gold -*- C++ -*-
3 // Copyright 2007, 2008, 2009, 2010, 2011, 2012 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.
23 #ifndef GOLD_DWARF_READER_H
24 #define GOLD_DWARF_READER_H
29 #include <sys/types.h>
32 #include "elfcpp_swap.h"
39 class Dwarf_info_reader;
40 struct LineStateMachine;
42 // This class is used to extract the section index and offset of
43 // the target of a relocation for a given offset within the section.
45 class Elf_reloc_mapper
55 // Initialize the relocation tracker for section RELOC_SHNDX.
57 initialize(unsigned int reloc_shndx, unsigned int reloc_type)
58 { return this->do_initialize(reloc_shndx, reloc_type); }
60 // Return the next reloc_offset.
63 { return this->do_next_offset(); }
65 // Advance to the next relocation past OFFSET.
68 { this->do_advance(offset); }
70 // Return the section index and offset within the section of the target
71 // of the relocation for RELOC_OFFSET in the referring section.
73 get_reloc_target(off_t reloc_offset, off_t* target_offset)
74 { return this->do_get_reloc_target(reloc_offset, target_offset); }
76 // Checkpoint the current position in the reloc section.
79 { return this->do_checkpoint(); }
81 // Reset the current position to the CHECKPOINT.
83 reset(uint64_t checkpoint)
84 { this->do_reset(checkpoint); }
88 do_initialize(unsigned int, unsigned int) = 0;
90 // Return the next reloc_offset.
94 // Advance to the next relocation past OFFSET.
96 do_advance(off_t offset) = 0;
99 do_get_reloc_target(off_t reloc_offset, off_t* target_offset) = 0;
101 // Checkpoint the current position in the reloc section.
103 do_checkpoint() const = 0;
105 // Reset the current position to the CHECKPOINT.
107 do_reset(uint64_t checkpoint) = 0;
110 template<int size, bool big_endian>
111 class Sized_elf_reloc_mapper : public Elf_reloc_mapper
114 Sized_elf_reloc_mapper(Object* object, const unsigned char* symtab,
116 : object_(object), symtab_(symtab), symtab_size_(symtab_size),
117 reloc_type_(0), track_relocs_()
122 do_initialize(unsigned int reloc_shndx, unsigned int reloc_type);
124 // Return the next reloc_offset.
127 { return this->track_relocs_.next_offset(); }
129 // Advance to the next relocation past OFFSET.
131 do_advance(off_t offset)
132 { this->track_relocs_.advance(offset); }
135 do_get_reloc_target(off_t reloc_offset, off_t* target_offset);
137 // Checkpoint the current position in the reloc section.
139 do_checkpoint() const
140 { return this->track_relocs_.checkpoint(); }
142 // Reset the current position to the CHECKPOINT.
144 do_reset(uint64_t checkpoint)
145 { this->track_relocs_.reset(checkpoint); }
148 typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
150 // Return the section index of symbol SYMNDX, and copy its value to *VALUE.
151 // Set *IS_ORDINARY true if the section index is an ordinary section index.
153 symbol_section(unsigned int symndx, Address* value, bool* is_ordinary);
157 // The ELF symbol table.
158 const unsigned char* symtab_;
159 // The size of the ELF symbol table.
161 // Type of the relocation section (SHT_REL or SHT_RELA).
162 unsigned int reloc_type_;
163 // Relocations for the referring section.
164 Track_relocs<size, big_endian> track_relocs_;
167 // This class is used to read the abbreviations table from the
168 // .debug_abbrev section of the object file.
170 class Dwarf_abbrev_table
173 // An attribute list entry.
176 Attribute(unsigned int a, unsigned int f)
183 // An abbrev code entry.
186 Abbrev_code(unsigned int t, bool hc)
187 : tag(t), has_children(hc), has_sibling_attribute(false), attributes()
189 this->attributes.reserve(10);
193 add_attribute(unsigned int attr, unsigned int form)
195 this->attributes.push_back(Attribute(attr, form));
200 // True if the DIE has children.
201 bool has_children : 1;
202 // True if the DIE has a sibling attribute.
203 bool has_sibling_attribute : 1;
204 // The list of attributes and forms.
205 std::vector<Attribute> attributes;
209 : abbrev_shndx_(0), abbrev_offset_(0), buffer_(NULL), buffer_end_(NULL),
210 owns_buffer_(false), buffer_pos_(NULL), high_abbrev_codes_()
212 memset(this->low_abbrev_codes_, 0, sizeof(this->low_abbrev_codes_));
215 ~Dwarf_abbrev_table()
217 if (this->owns_buffer_ && this->buffer_ != NULL)
218 delete[] this->buffer_;
219 this->clear_abbrev_codes();
222 // Read the abbrev table from an object file.
224 read_abbrevs(Relobj* object,
225 unsigned int abbrev_shndx,
228 // If we've already read this abbrev table, return immediately.
229 if (this->abbrev_shndx_ > 0
230 && this->abbrev_shndx_ == abbrev_shndx
231 && this->abbrev_offset_ == abbrev_offset)
233 return this->do_read_abbrevs(object, abbrev_shndx, abbrev_offset);
236 // Return the abbrev code entry for CODE. This is a fast path for
237 // abbrev codes that are in the direct lookup table. If not found
238 // there, we call do_get_abbrev() to do the hard work.
240 get_abbrev(unsigned int code)
242 if (code < this->low_abbrev_code_max_
243 && this->low_abbrev_codes_[code] != NULL)
244 return this->low_abbrev_codes_[code];
245 return this->do_get_abbrev(code);
249 // Read the abbrev table from an object file.
251 do_read_abbrevs(Relobj* object,
252 unsigned int abbrev_shndx,
253 off_t abbrev_offset);
255 // Lookup the abbrev code entry for CODE.
257 do_get_abbrev(unsigned int code);
259 // Store an abbrev code entry for CODE.
261 store_abbrev(unsigned int code, const Abbrev_code* entry)
263 if (code < this->low_abbrev_code_max_)
264 this->low_abbrev_codes_[code] = entry;
266 this->high_abbrev_codes_[code] = entry;
269 // Clear the abbrev code table and release the memory it uses.
271 clear_abbrev_codes();
273 typedef Unordered_map<unsigned int, const Abbrev_code*> Abbrev_code_table;
275 // The section index of the current abbrev table.
276 unsigned int abbrev_shndx_;
277 // The offset within the section of the current abbrev table.
278 off_t abbrev_offset_;
279 // The buffer containing the .debug_abbrev section.
280 const unsigned char* buffer_;
281 const unsigned char* buffer_end_;
282 // True if this object owns the buffer and needs to delete it.
284 // Pointer to the current position in the buffer.
285 const unsigned char* buffer_pos_;
286 // The table of abbrev codes.
287 // We use a direct-lookup array for low abbrev codes,
288 // and store the rest in a hash table.
289 static const unsigned int low_abbrev_code_max_ = 256;
290 const Abbrev_code* low_abbrev_codes_[low_abbrev_code_max_];
291 Abbrev_code_table high_abbrev_codes_;
294 // A DWARF range list. The start and end offsets are relative
295 // to the input section SHNDX. Each range must lie entirely
296 // within a single section.
298 class Dwarf_range_list
303 Range(unsigned int a_shndx, off_t a_start, off_t a_end)
304 : shndx(a_shndx), start(a_start), end(a_end)
317 add(unsigned int shndx, off_t start, off_t end)
318 { this->range_list_.push_back(Range(shndx, start, end)); }
322 { return this->range_list_.size(); }
325 operator[](off_t i) const
326 { return this->range_list_[i]; }
329 std::vector<Range> range_list_;
332 // This class is used to read the ranges table from the
333 // .debug_ranges section of the object file.
335 class Dwarf_ranges_table
338 Dwarf_ranges_table(Dwarf_info_reader* dwinfo)
339 : dwinfo_(dwinfo), ranges_shndx_(0), ranges_buffer_(NULL),
340 ranges_buffer_end_(NULL), owns_ranges_buffer_(false),
341 ranges_reloc_mapper_(NULL), reloc_type_(0), output_section_offset_(0)
344 ~Dwarf_ranges_table()
346 if (this->owns_ranges_buffer_ && this->ranges_buffer_ != NULL)
347 delete[] this->ranges_buffer_;
348 if (this->ranges_reloc_mapper_ != NULL)
349 delete this->ranges_reloc_mapper_;
352 // Read the ranges table from an object file.
354 read_ranges_table(Relobj* object,
355 const unsigned char* symtab,
357 unsigned int ranges_shndx);
359 // Read the range table from an object file.
361 read_range_list(Relobj* object,
362 const unsigned char* symtab,
364 unsigned int address_size,
365 unsigned int ranges_shndx,
366 off_t ranges_offset);
368 // Look for a relocation at offset OFF in the range table,
369 // and return the section index and offset of the target.
371 lookup_reloc(off_t off, off_t* target_off);
374 // The Dwarf_info_reader, for reading data.
375 Dwarf_info_reader* dwinfo_;
376 // The section index of the ranges table.
377 unsigned int ranges_shndx_;
378 // The buffer containing the .debug_ranges section.
379 const unsigned char* ranges_buffer_;
380 const unsigned char* ranges_buffer_end_;
381 // True if this object owns the buffer and needs to delete it.
382 bool owns_ranges_buffer_;
383 // Relocation mapper for the .debug_ranges section.
384 Elf_reloc_mapper* ranges_reloc_mapper_;
385 // Type of the relocation section (SHT_REL or SHT_RELA).
386 unsigned int reloc_type_;
387 // For incremental update links, this will hold the offset of the
388 // input section within the output section. Offsets read from
389 // relocated data will be relative to the output section, and need
390 // to be corrected before reading data from the input section.
391 uint64_t output_section_offset_;
394 // This class is used to read the pubnames and pubtypes tables from the
395 // .debug_pubnames and .debug_pubtypes sections of the object file.
397 class Dwarf_pubnames_table
400 Dwarf_pubnames_table(Dwarf_info_reader* dwinfo, bool is_pubtypes)
401 : dwinfo_(dwinfo), buffer_(NULL), buffer_end_(NULL), owns_buffer_(false),
402 offset_size_(0), pinfo_(NULL), is_pubtypes_(is_pubtypes),
403 output_section_offset_(0), unit_length_(0), cu_offset_(0)
406 ~Dwarf_pubnames_table()
408 if (this->owns_buffer_ && this->buffer_ != NULL)
409 delete[] this->buffer_;
412 // Read the pubnames section from the object file, using the symbol
413 // table for relocating it.
415 read_section(Relobj* object, const unsigned char* symbol_table,
418 // Read the header for the set at OFFSET.
420 read_header(off_t offset);
422 // Return the offset to the cu within the info or types section.
425 { return this->cu_offset_; }
427 // Return the size of this subsection of the table. The unit length
428 // doesn't include the size of its own field.
431 { return this->unit_length_; }
433 // Read the next name from the set.
438 // The Dwarf_info_reader, for reading data.
439 Dwarf_info_reader* dwinfo_;
440 // The buffer containing the .debug_ranges section.
441 const unsigned char* buffer_;
442 const unsigned char* buffer_end_;
443 // True if this object owns the buffer and needs to delete it.
445 // The size of a DWARF offset for the current set.
446 unsigned int offset_size_;
447 // The current position within the buffer.
448 const unsigned char* pinfo_;
449 // TRUE if this is a .debug_pubtypes section.
451 // For incremental update links, this will hold the offset of the
452 // input section within the output section. Offsets read from
453 // relocated data will be relative to the output section, and need
454 // to be corrected before reading data from the input section.
455 uint64_t output_section_offset_;
456 // Fields read from the header.
457 uint64_t unit_length_;
460 // Track relocations for this table so we can find the CUs that
461 // correspond to the subsections.
462 Elf_reloc_mapper* reloc_mapper_;
463 // Type of the relocation section (SHT_REL or SHT_RELA).
464 unsigned int reloc_type_;
467 // This class represents a DWARF Debug Info Entry (DIE).
472 // An attribute value.
473 struct Attribute_value
481 const char* stringval;
482 const unsigned char* blockval;
487 // Section index for reference forms.
489 // Block length for block forms.
490 unsigned int blocklen;
491 // Attribute offset for DW_FORM_strp.
492 unsigned int attr_off;
496 // A list of attribute values.
497 typedef std::vector<Attribute_value> Attributes;
499 Dwarf_die(Dwarf_info_reader* dwinfo,
503 // Return the DWARF tag for this DIE.
507 if (this->abbrev_code_ == NULL)
509 return this->abbrev_code_->tag;
512 // Return true if this DIE has children.
516 gold_assert(this->abbrev_code_ != NULL);
517 return this->abbrev_code_->has_children;
520 // Return true if this DIE has a sibling attribute.
522 has_sibling_attribute() const
524 gold_assert(this->abbrev_code_ != NULL);
525 return this->abbrev_code_->has_sibling_attribute;
528 // Return the value of attribute ATTR.
529 const Attribute_value*
530 attribute(unsigned int attr);
532 // Return the value of the DW_AT_name attribute.
536 if (this->name_ == NULL)
541 // Return the value of the DW_AT_linkage_name
542 // or DW_AT_MIPS_linkage_name attribute.
546 if (this->linkage_name_ == NULL)
547 this->set_linkage_name();
548 return this->linkage_name_;
551 // Return the value of the DW_AT_specification attribute.
555 if (!this->attributes_read_)
556 this->read_attributes();
557 return this->specification_;
560 // Return the value of the DW_AT_abstract_origin attribute.
564 if (!this->attributes_read_)
565 this->read_attributes();
566 return this->abstract_origin_;
569 // Return the value of attribute ATTR as a string.
571 string_attribute(unsigned int attr);
573 // Return the value of attribute ATTR as an integer.
575 int_attribute(unsigned int attr);
577 // Return the value of attribute ATTR as an unsigned integer.
579 uint_attribute(unsigned int attr);
581 // Return the value of attribute ATTR as a reference.
583 ref_attribute(unsigned int attr, unsigned int* shndx);
585 // Return the value of attribute ATTR as a address.
587 address_attribute(unsigned int attr, unsigned int* shndx);
589 // Return the value of attribute ATTR as a flag.
591 flag_attribute(unsigned int attr)
592 { return this->int_attribute(attr) != 0; }
594 // Return true if this DIE is a declaration.
597 { return this->flag_attribute(elfcpp::DW_AT_declaration); }
599 // Return the parent of this DIE.
602 { return this->parent_; }
604 // Return the offset of this DIE.
607 { return this->die_offset_; }
609 // Return the offset of this DIE's first child.
613 // Set the offset of this DIE's next sibling.
615 set_sibling_offset(off_t sibling_offset)
616 { this->sibling_offset_ = sibling_offset; }
618 // Return the offset of this DIE's next sibling.
623 typedef Dwarf_abbrev_table::Abbrev_code Abbrev_code;
625 // Read all the attributes of the DIE.
629 // Set the name of the DIE if present.
633 // Set the linkage name if present.
637 // Skip all the attributes of the DIE and return the offset
642 // The Dwarf_info_reader, for reading attributes.
643 Dwarf_info_reader* dwinfo_;
644 // The parent of this DIE.
646 // Offset of this DIE within its compilation unit.
648 // Offset of the first attribute, relative to the beginning of the DIE.
650 // Offset of the first child, relative to the compilation unit.
652 // Offset of the next sibling, relative to the compilation unit.
653 off_t sibling_offset_;
654 // The abbreviation table entry.
655 const Abbrev_code* abbrev_code_;
656 // The list of attributes.
657 Attributes attributes_;
658 // True if the attributes have been read.
659 bool attributes_read_;
660 // The following fields hold common attributes to avoid a linear
661 // search through the attribute list.
662 // The DIE name (DW_AT_name).
664 // Offset of the name in the string table (for DW_FORM_strp).
666 // The linkage name (DW_AT_linkage_name or DW_AT_MIPS_linkage_name).
667 const char* linkage_name_;
668 // Offset of the linkage name in the string table (for DW_FORM_strp).
669 off_t linkage_name_off_;
670 // Section index of the string table (for DW_FORM_strp).
671 unsigned int string_shndx_;
672 // The value of a DW_AT_specification attribute.
673 off_t specification_;
674 // The value of a DW_AT_abstract_origin attribute.
675 off_t abstract_origin_;
678 // This class is used to read the debug info from the .debug_info
679 // or .debug_types sections. This is a base class that implements
680 // the generic parsing of the compilation unit header and DIE
681 // structure. The parse() method parses the entire section, and
682 // calls the various visit_xxx() methods for each header. Clients
683 // should derive a new class from this one and implement the
684 // visit_compilation_unit() and visit_type_unit() functions.
686 class Dwarf_info_reader
689 Dwarf_info_reader(bool is_type_unit,
691 const unsigned char* symtab,
694 unsigned int reloc_shndx,
695 unsigned int reloc_type)
696 : is_type_unit_(is_type_unit), object_(object), symtab_(symtab),
697 symtab_size_(symtab_size), shndx_(shndx), reloc_shndx_(reloc_shndx),
698 reloc_type_(reloc_type), abbrev_shndx_(0), string_shndx_(0),
699 buffer_(NULL), buffer_end_(NULL), cu_offset_(0), cu_length_(0),
700 offset_size_(0), address_size_(0), cu_version_(0), type_signature_(0),
701 type_offset_(0), abbrev_table_(), ranges_table_(this),
702 reloc_mapper_(NULL), string_buffer_(NULL), string_buffer_end_(NULL),
703 owns_string_buffer_(false), string_output_section_offset_(0)
709 if (this->reloc_mapper_ != NULL)
710 delete this->reloc_mapper_;
711 if (this->owns_string_buffer_ && this->string_buffer_ != NULL)
712 delete[] this->string_buffer_;
715 // Begin parsing the debug info. This calls visit_compilation_unit()
716 // or visit_type_unit() for each compilation or type unit found in the
717 // section, and visit_die() for each top-level DIE.
721 // Return the abbrev code entry for a CODE.
722 const Dwarf_abbrev_table::Abbrev_code*
723 get_abbrev(unsigned int code)
724 { return this->abbrev_table_.get_abbrev(code); }
726 // Return a pointer to the DWARF info buffer at OFFSET.
728 buffer_at_offset(off_t offset) const
730 const unsigned char* p = this->buffer_ + this->cu_offset_ + offset;
731 if (this->check_buffer(p + 1))
736 // Read a possibly unaligned integer of SIZE.
737 template <int valsize>
738 inline typename elfcpp::Valtype_base<valsize>::Valtype
739 read_from_pointer(const unsigned char* source);
741 // Read a possibly unaligned integer of SIZE. Update SOURCE after read.
742 template <int valsize>
743 inline typename elfcpp::Valtype_base<valsize>::Valtype
744 read_from_pointer(const unsigned char** source);
746 // Look for a relocation at offset ATTR_OFF in the dwarf info,
747 // and return the section index and offset of the target.
749 lookup_reloc(off_t attr_off, off_t* target_off);
751 // Return a string from the DWARF string table.
753 get_string(off_t str_off, unsigned int string_shndx);
755 // Return the size of a DWARF offset.
758 { return this->offset_size_; }
760 // Return the size of an address.
763 { return this->address_size_; }
765 // Set the section index of the .debug_abbrev section.
766 // We use this if there are no relocations for the .debug_info section.
767 // If not set, the code parse() routine will search for the section by name.
769 set_abbrev_shndx(unsigned int abbrev_shndx)
770 { this->abbrev_shndx_ = abbrev_shndx; }
772 // Return a pointer to the object file's ELF symbol table.
775 { return this->symtab_; }
777 // Return the size of the object file's ELF symbol table.
780 { return this->symtab_size_; }
782 // Return the offset of the current compilation unit.
785 { return this->cu_offset_; }
788 // Begin parsing the debug info. This calls visit_compilation_unit()
789 // or visit_type_unit() for each compilation or type unit found in the
790 // section, and visit_die() for each top-level DIE.
791 template<bool big_endian>
795 // The following methods are hooks that are meant to be implemented
796 // by a derived class. A default, do-nothing, implementation of
797 // each is provided for this base class.
799 // Visit a compilation unit.
801 visit_compilation_unit(off_t cu_offset, off_t cu_length, Dwarf_die* root_die);
803 // Visit a type unit.
805 visit_type_unit(off_t tu_offset, off_t type_offset, uint64_t signature,
806 Dwarf_die* root_die);
808 // Read the range table.
810 read_range_list(unsigned int ranges_shndx, off_t ranges_offset)
812 return this->ranges_table_.read_range_list(this->object_,
820 // Return the object.
823 { return this->object_; }
825 // Checkpoint the relocation tracker.
827 get_reloc_checkpoint() const
828 { return this->reloc_mapper_->checkpoint(); }
830 // Reset the relocation tracker to the CHECKPOINT.
832 reset_relocs(uint64_t checkpoint)
833 { this->reloc_mapper_->reset(checkpoint); }
836 // Print a warning about a corrupt debug section.
838 warn_corrupt_debug_section() const;
840 // Check that P is within the bounds of the current section.
842 check_buffer(const unsigned char* p) const
844 if (p > this->buffer_ + this->cu_offset_ + this->cu_length_)
846 this->warn_corrupt_debug_section();
852 // Read the DWARF string table.
854 read_string_table(unsigned int string_shndx)
856 // If we've already read this string table, return immediately.
857 if (this->string_shndx_ > 0 && this->string_shndx_ == string_shndx)
859 if (string_shndx == 0 && this->string_shndx_ > 0)
861 return this->do_read_string_table(string_shndx);
865 do_read_string_table(unsigned int string_shndx);
867 // True if this is a type unit; false for a compilation unit.
869 // The object containing the .debug_info or .debug_types input section.
871 // The ELF symbol table.
872 const unsigned char* symtab_;
873 // The size of the ELF symbol table.
875 // Index of the .debug_info or .debug_types section.
877 // Index of the relocation section.
878 unsigned int reloc_shndx_;
879 // Type of the relocation section (SHT_REL or SHT_RELA).
880 unsigned int reloc_type_;
881 // Index of the .debug_abbrev section (0 if not known).
882 unsigned int abbrev_shndx_;
883 // Index of the .debug_str section.
884 unsigned int string_shndx_;
885 // The buffer for the debug info.
886 const unsigned char* buffer_;
887 const unsigned char* buffer_end_;
888 // Offset of the current compilation unit.
890 // Length of the current compilation unit.
892 // Size of a DWARF offset for the current compilation unit.
893 unsigned int offset_size_;
894 // Size of an address for the target architecture.
895 unsigned int address_size_;
896 // Compilation unit version number.
897 unsigned int cu_version_;
898 // Type signature (for a type unit).
899 uint64_t type_signature_;
900 // Offset from the type unit header to the type DIE (for a type unit).
902 // Abbreviations table for current compilation unit.
903 Dwarf_abbrev_table abbrev_table_;
904 // Ranges table for the current compilation unit.
905 Dwarf_ranges_table ranges_table_;
906 // Relocation mapper for the section.
907 Elf_reloc_mapper* reloc_mapper_;
908 // The buffer for the debug string table.
909 const char* string_buffer_;
910 const char* string_buffer_end_;
911 // True if this object owns the buffer and needs to delete it.
912 bool owns_string_buffer_;
913 // For incremental update links, this will hold the offset of the
914 // input .debug_str section within the output section. Offsets read
915 // from relocated data will be relative to the output section, and need
916 // to be corrected before reading data from the input section.
917 uint64_t string_output_section_offset_;
920 // We can't do better than to keep the offsets in a sorted vector.
921 // Here, offset is the key, and file_num/line_num is the value.
922 struct Offset_to_lineno_entry
925 int header_num; // which file-list to use (i.e. which .o file are we in)
926 // A pointer into files_.
927 unsigned int file_num : sizeof(int) * CHAR_BIT - 1;
928 // True if this was the last entry for the current offset, meaning
929 // it's the line that actually applies.
930 unsigned int last_line_for_offset : 1;
931 // The line number in the source file. -1 to indicate end-of-function.
934 // This sorts by offsets first, and then puts the correct line to
935 // report for a given offset at the beginning of the run of equal
936 // offsets (so that asking for 1 line gives the best answer). This
937 // is not a total ordering.
938 bool operator<(const Offset_to_lineno_entry& that) const
940 if (this->offset != that.offset)
941 return this->offset < that.offset;
942 // Note the '>' which makes this sort 'true' first.
943 return this->last_line_for_offset > that.last_line_for_offset;
947 // This class is used to read the line information from the debugging
948 // section of an object file.
950 class Dwarf_line_info
960 // Given a section number and an offset, returns the associated
961 // file and line-number, as a string: "file:lineno". If unable
962 // to do the mapping, returns the empty string. You must call
963 // read_line_mappings() before calling this function. If
964 // 'other_lines' is non-NULL, fills that in with other line
965 // numbers assigned to the same offset.
967 addr2line(unsigned int shndx, off_t offset,
968 std::vector<std::string>* other_lines)
969 { return this->do_addr2line(shndx, offset, other_lines); }
971 // A helper function for a single addr2line lookup. It also keeps a
972 // cache of the last CACHE_SIZE Dwarf_line_info objects it created;
973 // set to 0 not to cache at all. The larger CACHE_SIZE is, the more
974 // chance this routine won't have to re-create a Dwarf_line_info
975 // object for its addr2line computation; such creations are slow.
976 // NOTE: Not thread-safe, so only call from one thread at a time.
978 one_addr2line(Object* object, unsigned int shndx, off_t offset,
979 size_t cache_size, std::vector<std::string>* other_lines);
981 // This reclaims all the memory that one_addr2line may have cached.
982 // Use this when you know you will not be calling one_addr2line again.
984 clear_addr2line_cache();
988 do_addr2line(unsigned int shndx, off_t offset,
989 std::vector<std::string>* other_lines) = 0;
992 template<int size, bool big_endian>
993 class Sized_dwarf_line_info : public Dwarf_line_info
996 // Initializes a .debug_line reader for a given object file.
997 // If SHNDX is specified and non-negative, only read the debug
998 // information that pertains to the specified section.
999 Sized_dwarf_line_info(Object* object, unsigned int read_shndx = -1U);
1002 ~Sized_dwarf_line_info()
1004 if (this->buffer_start_ != NULL)
1005 delete[] this->buffer_start_;
1010 do_addr2line(unsigned int shndx, off_t offset,
1011 std::vector<std::string>* other_lines);
1013 // Formats a file and line number to a string like "dirname/filename:lineno".
1015 format_file_lineno(const Offset_to_lineno_entry& lineno) const;
1017 // Start processing line info, and populates the offset_map_.
1018 // If SHNDX is non-negative, only store debug information that
1019 // pertains to the specified section.
1021 read_line_mappings(unsigned int shndx);
1023 // Reads the relocation section associated with .debug_line and
1024 // stores relocation information in reloc_map_.
1028 // Reads the DWARF2/3 header for this line info. Each takes as input
1029 // a starting buffer position, and returns the ending position.
1030 const unsigned char*
1031 read_header_prolog(const unsigned char* lineptr);
1033 const unsigned char*
1034 read_header_tables(const unsigned char* lineptr);
1036 // Reads the DWARF2/3 line information. If shndx is non-negative,
1037 // discard all line information that doesn't pertain to the given
1039 const unsigned char*
1040 read_lines(const unsigned char* lineptr, unsigned int shndx);
1042 // Process a single line info opcode at START using the state
1043 // machine at LSM. Return true if we should define a line using the
1044 // current state of the line state machine. Place the length of the
1047 process_one_opcode(const unsigned char* start,
1048 struct LineStateMachine* lsm, size_t* len);
1050 // Some parts of processing differ depending on whether the input
1051 // was a .o file or not.
1052 bool input_is_relobj();
1054 // If we saw anything amiss while parsing, we set this to false.
1055 // Then addr2line will always fail (rather than return possibly-
1059 // A DWARF2/3 line info header. This is not the same size as in the
1060 // actual file, as the one in the file may have a 32 bit or 64 bit
1063 struct Dwarf_line_infoHeader
1067 off_t prologue_length;
1068 int min_insn_length; // insn stands for instructin
1069 bool default_is_stmt; // stmt stands for statement
1070 signed char line_base;
1072 unsigned char opcode_base;
1073 std::vector<unsigned char> std_opcode_lengths;
1077 // buffer is the buffer for our line info, starting at exactly where
1078 // the line info to read is.
1079 const unsigned char* buffer_;
1080 const unsigned char* buffer_end_;
1081 // If the buffer was allocated temporarily, and therefore must be
1082 // deallocated in the dtor, this contains a pointer to the start
1084 const unsigned char* buffer_start_;
1086 // This has relocations that point into buffer.
1087 Sized_elf_reloc_mapper<size, big_endian>* reloc_mapper_;
1088 // The type of the reloc section in track_relocs_--SHT_REL or SHT_RELA.
1089 unsigned int track_relocs_type_;
1091 // This is used to figure out what section to apply a relocation to.
1092 const unsigned char* symtab_buffer_;
1093 section_size_type symtab_buffer_size_;
1095 // Holds the directories and files as we see them. We have an array
1096 // of directory-lists, one for each .o file we're reading (usually
1097 // there will just be one, but there may be more if input is a .so).
1098 std::vector<std::vector<std::string> > directories_;
1099 // The first part is an index into directories_, the second the filename.
1100 std::vector<std::vector< std::pair<int, std::string> > > files_;
1102 // An index into the current directories_ and files_ vectors.
1103 int current_header_index_;
1105 // A sorted map from offset of the relocation target to the shndx
1106 // and addend for the relocation.
1107 typedef std::map<off_t, std::pair<unsigned int, off_t> >
1109 Reloc_map reloc_map_;
1111 // We have a vector of offset->lineno entries for every input section.
1112 typedef Unordered_map<unsigned int, std::vector<Offset_to_lineno_entry> >
1115 Lineno_map line_number_map_;
1118 } // End namespace gold.
1120 #endif // !defined(GOLD_DWARF_READER_H)