| // dwarf_reader.h -- parse dwarf2/3 debug information for gold -*- C++ -*- |
| |
| // Copyright 2007, 2008, 2009, 2010 Free Software Foundation, Inc. |
| // Written by Ian Lance Taylor <iant@google.com>. |
| |
| // This file is part of gold. |
| |
| // This program is free software; you can redistribute it and/or modify |
| // it under the terms of the GNU General Public License as published by |
| // the Free Software Foundation; either version 3 of the License, or |
| // (at your option) any later version. |
| |
| // This program is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| // GNU General Public License for more details. |
| |
| // You should have received a copy of the GNU General Public License |
| // along with this program; if not, write to the Free Software |
| // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, |
| // MA 02110-1301, USA. |
| |
| #ifndef GOLD_DWARF_READER_H |
| #define GOLD_DWARF_READER_H |
| |
| #include <vector> |
| #include <map> |
| #include <limits.h> |
| |
| #include "elfcpp.h" |
| #include "elfcpp_swap.h" |
| #include "dwarf.h" |
| #include "reloc.h" |
| |
| namespace gold |
| { |
| |
| template<int size, bool big_endian> |
| class Track_relocs; |
| struct LineStateMachine; |
| |
| // We can't do better than to keep the offsets in a sorted vector. |
| // Here, offset is the key, and file_num/line_num is the value. |
| struct Offset_to_lineno_entry |
| { |
| off_t offset; |
| int header_num; // which file-list to use (i.e. which .o file are we in) |
| // A pointer into files_. |
| unsigned int file_num : sizeof(int) * CHAR_BIT - 1; |
| // True if this was the last entry for the current offset, meaning |
| // it's the line that actually applies. |
| unsigned int last_line_for_offset : 1; |
| // The line number in the source file. -1 to indicate end-of-function. |
| int line_num; |
| |
| // This sorts by offsets first, and then puts the correct line to |
| // report for a given offset at the beginning of the run of equal |
| // offsets (so that asking for 1 line gives the best answer). This |
| // is not a total ordering. |
| bool operator<(const Offset_to_lineno_entry& that) const |
| { |
| if (this->offset != that.offset) |
| return this->offset < that.offset; |
| // Note the '>' which makes this sort 'true' first. |
| return this->last_line_for_offset > that.last_line_for_offset; |
| } |
| }; |
| |
| // This class is used to read the line information from the debugging |
| // section of an object file. |
| |
| class Dwarf_line_info |
| { |
| public: |
| Dwarf_line_info() |
| { } |
| |
| virtual |
| ~Dwarf_line_info() |
| { } |
| |
| // Given a section number and an offset, returns the associated |
| // file and line-number, as a string: "file:lineno". If unable |
| // to do the mapping, returns the empty string. You must call |
| // read_line_mappings() before calling this function. If |
| // 'other_lines' is non-NULL, fills that in with other line |
| // numbers assigned to the same offset. |
| std::string |
| addr2line(unsigned int shndx, off_t offset, |
| std::vector<std::string>* other_lines) |
| { return this->do_addr2line(shndx, offset, other_lines); } |
| |
| // A helper function for a single addr2line lookup. It also keeps a |
| // cache of the last CACHE_SIZE Dwarf_line_info objects it created; |
| // set to 0 not to cache at all. The larger CACHE_SIZE is, the more |
| // chance this routine won't have to re-create a Dwarf_line_info |
| // object for its addr2line computation; such creations are slow. |
| // NOTE: Not thread-safe, so only call from one thread at a time. |
| static std::string |
| one_addr2line(Object* object, unsigned int shndx, off_t offset, |
| size_t cache_size, std::vector<std::string>* other_lines); |
| |
| // This reclaims all the memory that one_addr2line may have cached. |
| // Use this when you know you will not be calling one_addr2line again. |
| static void |
| clear_addr2line_cache(); |
| |
| private: |
| virtual std::string |
| do_addr2line(unsigned int shndx, off_t offset, |
| std::vector<std::string>* other_lines) = 0; |
| }; |
| |
| template<int size, bool big_endian> |
| class Sized_dwarf_line_info : public Dwarf_line_info |
| { |
| public: |
| // Initializes a .debug_line reader for a given object file. |
| // If SHNDX is specified and non-negative, only read the debug |
| // information that pertains to the specified section. |
| Sized_dwarf_line_info(Object* object, unsigned int read_shndx = -1U); |
| |
| private: |
| std::string |
| do_addr2line(unsigned int shndx, off_t offset, |
| std::vector<std::string>* other_lines); |
| |
| // Formats a file and line number to a string like "dirname/filename:lineno". |
| std::string |
| format_file_lineno(const Offset_to_lineno_entry& lineno) const; |
| |
| // Start processing line info, and populates the offset_map_. |
| // If SHNDX is non-negative, only store debug information that |
| // pertains to the specified section. |
| void |
| read_line_mappings(Object*, unsigned int shndx); |
| |
| // Reads the relocation section associated with .debug_line and |
| // stores relocation information in reloc_map_. |
| void |
| read_relocs(Object*); |
| |
| // Looks in the symtab to see what section a symbol is in. |
| unsigned int |
| symbol_section(Object*, unsigned int sym, |
| typename elfcpp::Elf_types<size>::Elf_Addr* value, |
| bool* is_ordinary); |
| |
| // Reads the DWARF2/3 header for this line info. Each takes as input |
| // a starting buffer position, and returns the ending position. |
| const unsigned char* |
| read_header_prolog(const unsigned char* lineptr); |
| |
| const unsigned char* |
| read_header_tables(const unsigned char* lineptr); |
| |
| // Reads the DWARF2/3 line information. If shndx is non-negative, |
| // discard all line information that doesn't pertain to the given |
| // section. |
| const unsigned char* |
| read_lines(const unsigned char* lineptr, unsigned int shndx); |
| |
| // Process a single line info opcode at START using the state |
| // machine at LSM. Return true if we should define a line using the |
| // current state of the line state machine. Place the length of the |
| // opcode in LEN. |
| bool |
| process_one_opcode(const unsigned char* start, |
| struct LineStateMachine* lsm, size_t* len); |
| |
| // Some parts of processing differ depending on whether the input |
| // was a .o file or not. |
| bool input_is_relobj(); |
| |
| // If we saw anything amiss while parsing, we set this to false. |
| // Then addr2line will always fail (rather than return possibly- |
| // corrupt data). |
| bool data_valid_; |
| |
| // A DWARF2/3 line info header. This is not the same size as in the |
| // actual file, as the one in the file may have a 32 bit or 64 bit |
| // lengths. |
| |
| struct Dwarf_line_infoHeader |
| { |
| off_t total_length; |
| int version; |
| off_t prologue_length; |
| int min_insn_length; // insn stands for instructin |
| bool default_is_stmt; // stmt stands for statement |
| signed char line_base; |
| int line_range; |
| unsigned char opcode_base; |
| std::vector<unsigned char> std_opcode_lengths; |
| int offset_size; |
| } header_; |
| |
| // buffer is the buffer for our line info, starting at exactly where |
| // the line info to read is. |
| const unsigned char* buffer_; |
| const unsigned char* buffer_end_; |
| |
| // This has relocations that point into buffer. |
| Track_relocs<size, big_endian> track_relocs_; |
| // The type of the reloc section in track_relocs_--SHT_REL or SHT_RELA. |
| unsigned int track_relocs_type_; |
| |
| // This is used to figure out what section to apply a relocation to. |
| const unsigned char* symtab_buffer_; |
| section_size_type symtab_buffer_size_; |
| |
| // Holds the directories and files as we see them. We have an array |
| // of directory-lists, one for each .o file we're reading (usually |
| // there will just be one, but there may be more if input is a .so). |
| std::vector<std::vector<std::string> > directories_; |
| // The first part is an index into directories_, the second the filename. |
| std::vector<std::vector< std::pair<int, std::string> > > files_; |
| |
| // An index into the current directories_ and files_ vectors. |
| int current_header_index_; |
| |
| // A sorted map from offset of the relocation target to the shndx |
| // and addend for the relocation. |
| typedef std::map<typename elfcpp::Elf_types<size>::Elf_Addr, |
| std::pair<unsigned int, |
| typename elfcpp::Elf_types<size>::Elf_Swxword> > |
| Reloc_map; |
| Reloc_map reloc_map_; |
| |
| // We have a vector of offset->lineno entries for every input section. |
| typedef Unordered_map<unsigned int, std::vector<Offset_to_lineno_entry> > |
| Lineno_map; |
| |
| Lineno_map line_number_map_; |
| }; |
| |
| } // End namespace gold. |
| |
| #endif // !defined(GOLD_DWARF_READER_H) |