1 // dwarf_reader.h -- parse dwarf2/3 debug information for gold -*- C++ -*-
3 // Copyright 2007 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
30 #include "elfcpp_swap.h"
37 template<int size
, bool big_endian
>
39 struct LineStateMachine
;
41 // This class is used to read the line information from the debugging
42 // section of an object file.
44 template<int size
, bool big_endian
>
48 // Initializes a .debug_line reader for a given object file.
49 Dwarf_line_info(Object
* object
);
51 // Given a section number and an offset, returns the associated
52 // file and line-number, as a string: "file:lineno". If unable
53 // to do the mapping, returns the empty string. You must call
54 // read_line_mappings() before calling this function.
56 addr2line(unsigned int shndx
, off_t offset
);
59 // Start processing line info, and populates the offset_map_.
63 // Reads the relocation section associated with .debug_line and
64 // stores relocation information in reloc_map_.
68 // Looks in the symtab to see what section a symbol is in.
70 symbol_section(unsigned int sym
,
71 typename
elfcpp::Elf_types
<size
>::Elf_Addr
* value
);
73 // Reads the DWARF2/3 header for this line info. Each takes as input
74 // a starting buffer position, and returns the ending position.
76 read_header_prolog(const unsigned char* lineptr
);
79 read_header_tables(const unsigned char* lineptr
);
81 // Reads the DWARF2/3 line information.
83 read_lines(const unsigned char* lineptr
);
85 // Process a single line info opcode at START using the state
86 // machine at LSM. Return true if we should define a line using the
87 // current state of the line state machine. Place the length of the
90 process_one_opcode(const unsigned char* start
,
91 struct LineStateMachine
* lsm
, size_t* len
);
93 // Some parts of processing differ depending on whether the input
94 // was a .o file or not.
95 bool input_is_relobj();
97 // If we saw anything amiss while parsing, we set this to false.
98 // Then addr2line will always fail (rather than return possibly-
102 // A DWARF2/3 line info header. This is not the same size as in the
103 // actual file, as the one in the file may have a 32 bit or 64 bit
106 struct Dwarf_line_infoHeader
110 off_t prologue_length
;
111 int min_insn_length
; // insn stands for instructin
112 bool default_is_stmt
; // stmt stands for statement
113 signed char line_base
;
115 unsigned char opcode_base
;
116 std::vector
<unsigned char> std_opcode_lengths
;
120 // buffer is the buffer for our line info, starting at exactly where
121 // the line info to read is.
122 const unsigned char* buffer_
;
123 const unsigned char* buffer_end_
;
125 // This has relocations that point into buffer.
126 Track_relocs
<size
, big_endian
> track_relocs_
;
128 // This is used to figure out what section to apply a relocation to.
129 const unsigned char* symtab_buffer_
;
130 off_t symtab_buffer_size_
;
132 // Holds the directories and files as we see them. We have an array
133 // of directory-lists, one for each .o file we're reading (usually
134 // there will just be one, but there may be more if input is a .so).
135 std::vector
<std::vector
<std::string
> > directories_
;
136 // The first part is an index into directories_, the second the filename.
137 std::vector
<std::vector
< std::pair
<int, std::string
> > > files_
;
139 // An index into the current directories_ and files_ vectors.
140 int current_header_index_
;
142 // A sorted map from offset of the relocation target to the shndx
143 // and addend for the relocation.
144 typedef std::map
<typename
elfcpp::Elf_types
<size
>::Elf_Addr
,
145 std::pair
<unsigned int,
146 typename
elfcpp::Elf_types
<size
>::Elf_Swxword
> >
148 Reloc_map reloc_map_
;
150 // We can't do better than to keep the offsets in a sorted vector.
151 // Here, offset is the key, and file_num/line_num is the value.
152 struct Offset_to_lineno_entry
155 int header_num
; // which file-list to use (i.e. which .o file are we in)
156 int file_num
; // a pointer into files_
157 int line_num
; // the line number in the source file
158 // Offsets are unique within a section, so that's a sufficient sort key.
159 bool operator<(const Offset_to_lineno_entry
& that
) const
160 { return this->offset
< that
.offset
; }
162 // We have a vector of offset->lineno entries for every input section.
163 typedef Unordered_map
<unsigned int, std::vector
<Offset_to_lineno_entry
> >
166 Lineno_map line_number_map_
;
169 } // End namespace gold.
171 #endif // !defined(GOLD_DWARF_READER_H)