| // dwarf_reader.cc -- parse dwarf2/3 debug information |
| |
| // 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. |
| |
| #include "gold.h" |
| |
| #include <algorithm> |
| #include <vector> |
| |
| #include "elfcpp_swap.h" |
| #include "dwarf.h" |
| #include "object.h" |
| #include "parameters.h" |
| #include "reloc.h" |
| #include "dwarf_reader.h" |
| #include "int_encoding.h" |
| #include "compressed_output.h" |
| |
| namespace gold { |
| |
| struct LineStateMachine |
| { |
| int file_num; |
| uint64_t address; |
| int line_num; |
| int column_num; |
| unsigned int shndx; // the section address refers to |
| bool is_stmt; // stmt means statement. |
| bool basic_block; |
| bool end_sequence; |
| }; |
| |
| static void |
| ResetLineStateMachine(struct LineStateMachine* lsm, bool default_is_stmt) |
| { |
| lsm->file_num = 1; |
| lsm->address = 0; |
| lsm->line_num = 1; |
| lsm->column_num = 0; |
| lsm->shndx = -1U; |
| lsm->is_stmt = default_is_stmt; |
| lsm->basic_block = false; |
| lsm->end_sequence = false; |
| } |
| |
| template<int size, bool big_endian> |
| Sized_dwarf_line_info<size, big_endian>::Sized_dwarf_line_info(Object* object, |
| unsigned int read_shndx) |
| : data_valid_(false), buffer_(NULL), symtab_buffer_(NULL), |
| directories_(), files_(), current_header_index_(-1) |
| { |
| unsigned int debug_shndx; |
| for (debug_shndx = 1; debug_shndx < object->shnum(); ++debug_shndx) |
| { |
| // FIXME: do this more efficiently: section_name() isn't super-fast |
| std::string name = object->section_name(debug_shndx); |
| if (name == ".debug_line" || name == ".zdebug_line") |
| { |
| section_size_type buffer_size; |
| this->buffer_ = object->section_contents(debug_shndx, &buffer_size, |
| false); |
| this->buffer_end_ = this->buffer_ + buffer_size; |
| break; |
| } |
| } |
| if (this->buffer_ == NULL) |
| return; |
| |
| section_size_type uncompressed_size = 0; |
| unsigned char* uncompressed_data = NULL; |
| if (object->section_is_compressed(debug_shndx, &uncompressed_size)) |
| { |
| uncompressed_data = new unsigned char[uncompressed_size]; |
| if (!decompress_input_section(this->buffer_, |
| this->buffer_end_ - this->buffer_, |
| uncompressed_data, |
| uncompressed_size)) |
| object->error(_("could not decompress section %s"), |
| object->section_name(debug_shndx).c_str()); |
| this->buffer_ = uncompressed_data; |
| this->buffer_end_ = this->buffer_ + uncompressed_size; |
| } |
| |
| // Find the relocation section for ".debug_line". |
| // We expect these for relobjs (.o's) but not dynobjs (.so's). |
| bool got_relocs = false; |
| for (unsigned int reloc_shndx = 0; |
| reloc_shndx < object->shnum(); |
| ++reloc_shndx) |
| { |
| unsigned int reloc_sh_type = object->section_type(reloc_shndx); |
| if ((reloc_sh_type == elfcpp::SHT_REL |
| || reloc_sh_type == elfcpp::SHT_RELA) |
| && object->section_info(reloc_shndx) == debug_shndx) |
| { |
| got_relocs = this->track_relocs_.initialize(object, reloc_shndx, |
| reloc_sh_type); |
| this->track_relocs_type_ = reloc_sh_type; |
| break; |
| } |
| } |
| |
| // Finally, we need the symtab section to interpret the relocs. |
| if (got_relocs) |
| { |
| unsigned int symtab_shndx; |
| for (symtab_shndx = 0; symtab_shndx < object->shnum(); ++symtab_shndx) |
| if (object->section_type(symtab_shndx) == elfcpp::SHT_SYMTAB) |
| { |
| this->symtab_buffer_ = object->section_contents( |
| symtab_shndx, &this->symtab_buffer_size_, false); |
| break; |
| } |
| if (this->symtab_buffer_ == NULL) |
| return; |
| } |
| |
| // Now that we have successfully read all the data, parse the debug |
| // info. |
| this->data_valid_ = true; |
| this->read_line_mappings(object, read_shndx); |
| } |
| |
| // Read the DWARF header. |
| |
| template<int size, bool big_endian> |
| const unsigned char* |
| Sized_dwarf_line_info<size, big_endian>::read_header_prolog( |
| const unsigned char* lineptr) |
| { |
| uint32_t initial_length = elfcpp::Swap_unaligned<32, big_endian>::readval(lineptr); |
| lineptr += 4; |
| |
| // In DWARF2/3, if the initial length is all 1 bits, then the offset |
| // size is 8 and we need to read the next 8 bytes for the real length. |
| if (initial_length == 0xffffffff) |
| { |
| header_.offset_size = 8; |
| initial_length = elfcpp::Swap_unaligned<64, big_endian>::readval(lineptr); |
| lineptr += 8; |
| } |
| else |
| header_.offset_size = 4; |
| |
| header_.total_length = initial_length; |
| |
| gold_assert(lineptr + header_.total_length <= buffer_end_); |
| |
| header_.version = elfcpp::Swap_unaligned<16, big_endian>::readval(lineptr); |
| lineptr += 2; |
| |
| if (header_.offset_size == 4) |
| header_.prologue_length = elfcpp::Swap_unaligned<32, big_endian>::readval(lineptr); |
| else |
| header_.prologue_length = elfcpp::Swap_unaligned<64, big_endian>::readval(lineptr); |
| lineptr += header_.offset_size; |
| |
| header_.min_insn_length = *lineptr; |
| lineptr += 1; |
| |
| header_.default_is_stmt = *lineptr; |
| lineptr += 1; |
| |
| header_.line_base = *reinterpret_cast<const signed char*>(lineptr); |
| lineptr += 1; |
| |
| header_.line_range = *lineptr; |
| lineptr += 1; |
| |
| header_.opcode_base = *lineptr; |
| lineptr += 1; |
| |
| header_.std_opcode_lengths.reserve(header_.opcode_base + 1); |
| header_.std_opcode_lengths[0] = 0; |
| for (int i = 1; i < header_.opcode_base; i++) |
| { |
| header_.std_opcode_lengths[i] = *lineptr; |
| lineptr += 1; |
| } |
| |
| return lineptr; |
| } |
| |
| // The header for a debug_line section is mildly complicated, because |
| // the line info is very tightly encoded. |
| |
| template<int size, bool big_endian> |
| const unsigned char* |
| Sized_dwarf_line_info<size, big_endian>::read_header_tables( |
| const unsigned char* lineptr) |
| { |
| ++this->current_header_index_; |
| |
| // Create a new directories_ entry and a new files_ entry for our new |
| // header. We initialize each with a single empty element, because |
| // dwarf indexes directory and filenames starting at 1. |
| gold_assert(static_cast<int>(this->directories_.size()) |
| == this->current_header_index_); |
| gold_assert(static_cast<int>(this->files_.size()) |
| == this->current_header_index_); |
| this->directories_.push_back(std::vector<std::string>(1)); |
| this->files_.push_back(std::vector<std::pair<int, std::string> >(1)); |
| |
| // It is legal for the directory entry table to be empty. |
| if (*lineptr) |
| { |
| int dirindex = 1; |
| while (*lineptr) |
| { |
| const char* dirname = reinterpret_cast<const char*>(lineptr); |
| gold_assert(dirindex |
| == static_cast<int>(this->directories_.back().size())); |
| this->directories_.back().push_back(dirname); |
| lineptr += this->directories_.back().back().size() + 1; |
| dirindex++; |
| } |
| } |
| lineptr++; |
| |
| // It is also legal for the file entry table to be empty. |
| if (*lineptr) |
| { |
| int fileindex = 1; |
| size_t len; |
| while (*lineptr) |
| { |
| const char* filename = reinterpret_cast<const char*>(lineptr); |
| lineptr += strlen(filename) + 1; |
| |
| uint64_t dirindex = read_unsigned_LEB_128(lineptr, &len); |
| lineptr += len; |
| |
| if (dirindex >= this->directories_.back().size()) |
| dirindex = 0; |
| int dirindexi = static_cast<int>(dirindex); |
| |
| read_unsigned_LEB_128(lineptr, &len); // mod_time |
| lineptr += len; |
| |
| read_unsigned_LEB_128(lineptr, &len); // filelength |
| lineptr += len; |
| |
| gold_assert(fileindex |
| == static_cast<int>(this->files_.back().size())); |
| this->files_.back().push_back(std::make_pair(dirindexi, filename)); |
| fileindex++; |
| } |
| } |
| lineptr++; |
| |
| return lineptr; |
| } |
| |
| // Process a single opcode in the .debug.line structure. |
| |
| // Templating on size and big_endian would yield more efficient (and |
| // simpler) code, but would bloat the binary. Speed isn't important |
| // here. |
| |
| template<int size, bool big_endian> |
| bool |
| Sized_dwarf_line_info<size, big_endian>::process_one_opcode( |
| const unsigned char* start, struct LineStateMachine* lsm, size_t* len) |
| { |
| size_t oplen = 0; |
| size_t templen; |
| unsigned char opcode = *start; |
| oplen++; |
| start++; |
| |
| // If the opcode is great than the opcode_base, it is a special |
| // opcode. Most line programs consist mainly of special opcodes. |
| if (opcode >= header_.opcode_base) |
| { |
| opcode -= header_.opcode_base; |
| const int advance_address = ((opcode / header_.line_range) |
| * header_.min_insn_length); |
| lsm->address += advance_address; |
| |
| const int advance_line = ((opcode % header_.line_range) |
| + header_.line_base); |
| lsm->line_num += advance_line; |
| lsm->basic_block = true; |
| *len = oplen; |
| return true; |
| } |
| |
| // Otherwise, we have the regular opcodes |
| switch (opcode) |
| { |
| case elfcpp::DW_LNS_copy: |
| lsm->basic_block = false; |
| *len = oplen; |
| return true; |
| |
| case elfcpp::DW_LNS_advance_pc: |
| { |
| const uint64_t advance_address |
| = read_unsigned_LEB_128(start, &templen); |
| oplen += templen; |
| lsm->address += header_.min_insn_length * advance_address; |
| } |
| break; |
| |
| case elfcpp::DW_LNS_advance_line: |
| { |
| const uint64_t advance_line = read_signed_LEB_128(start, &templen); |
| oplen += templen; |
| lsm->line_num += advance_line; |
| } |
| break; |
| |
| case elfcpp::DW_LNS_set_file: |
| { |
| const uint64_t fileno = read_unsigned_LEB_128(start, &templen); |
| oplen += templen; |
| lsm->file_num = fileno; |
| } |
| break; |
| |
| case elfcpp::DW_LNS_set_column: |
| { |
| const uint64_t colno = read_unsigned_LEB_128(start, &templen); |
| oplen += templen; |
| lsm->column_num = colno; |
| } |
| break; |
| |
| case elfcpp::DW_LNS_negate_stmt: |
| lsm->is_stmt = !lsm->is_stmt; |
| break; |
| |
| case elfcpp::DW_LNS_set_basic_block: |
| lsm->basic_block = true; |
| break; |
| |
| case elfcpp::DW_LNS_fixed_advance_pc: |
| { |
| int advance_address; |
| advance_address = elfcpp::Swap_unaligned<16, big_endian>::readval(start); |
| oplen += 2; |
| lsm->address += advance_address; |
| } |
| break; |
| |
| case elfcpp::DW_LNS_const_add_pc: |
| { |
| const int advance_address = (header_.min_insn_length |
| * ((255 - header_.opcode_base) |
| / header_.line_range)); |
| lsm->address += advance_address; |
| } |
| break; |
| |
| case elfcpp::DW_LNS_extended_op: |
| { |
| const uint64_t extended_op_len |
| = read_unsigned_LEB_128(start, &templen); |
| start += templen; |
| oplen += templen + extended_op_len; |
| |
| const unsigned char extended_op = *start; |
| start++; |
| |
| switch (extended_op) |
| { |
| case elfcpp::DW_LNE_end_sequence: |
| // This means that the current byte is the one immediately |
| // after a set of instructions. Record the current line |
| // for up to one less than the current address. |
| lsm->line_num = -1; |
| lsm->end_sequence = true; |
| *len = oplen; |
| return true; |
| |
| case elfcpp::DW_LNE_set_address: |
| { |
| lsm->address = |
| elfcpp::Swap_unaligned<size, big_endian>::readval(start); |
| typename Reloc_map::const_iterator it |
| = this->reloc_map_.find(start - this->buffer_); |
| if (it != reloc_map_.end()) |
| { |
| // If this is a SHT_RELA section, then ignore the |
| // section contents. This assumes that this is a |
| // straight reloc which just uses the reloc addend. |
| // The reloc addend has already been included in the |
| // symbol value. |
| if (this->track_relocs_type_ == elfcpp::SHT_RELA) |
| lsm->address = 0; |
| // Add in the symbol value. |
| lsm->address += it->second.second; |
| lsm->shndx = it->second.first; |
| } |
| else |
| { |
| // If we're a normal .o file, with relocs, every |
| // set_address should have an associated relocation. |
| if (this->input_is_relobj()) |
| this->data_valid_ = false; |
| } |
| break; |
| } |
| case elfcpp::DW_LNE_define_file: |
| { |
| const char* filename = reinterpret_cast<const char*>(start); |
| templen = strlen(filename) + 1; |
| start += templen; |
| |
| uint64_t dirindex = read_unsigned_LEB_128(start, &templen); |
| oplen += templen; |
| |
| if (dirindex >= this->directories_.back().size()) |
| dirindex = 0; |
| int dirindexi = static_cast<int>(dirindex); |
| |
| read_unsigned_LEB_128(start, &templen); // mod_time |
| oplen += templen; |
| |
| read_unsigned_LEB_128(start, &templen); // filelength |
| oplen += templen; |
| |
| this->files_.back().push_back(std::make_pair(dirindexi, |
| filename)); |
| } |
| break; |
| } |
| } |
| break; |
| |
| default: |
| { |
| // Ignore unknown opcode silently |
| for (int i = 0; i < header_.std_opcode_lengths[opcode]; i++) |
| { |
| size_t templen; |
| read_unsigned_LEB_128(start, &templen); |
| start += templen; |
| oplen += templen; |
| } |
| } |
| break; |
| } |
| *len = oplen; |
| return false; |
| } |
| |
| // Read the debug information at LINEPTR and store it in the line |
| // number map. |
| |
| template<int size, bool big_endian> |
| unsigned const char* |
| Sized_dwarf_line_info<size, big_endian>::read_lines(unsigned const char* lineptr, |
| unsigned int shndx) |
| { |
| struct LineStateMachine lsm; |
| |
| // LENGTHSTART is the place the length field is based on. It is the |
| // point in the header after the initial length field. |
| const unsigned char* lengthstart = buffer_; |
| |
| // In 64 bit dwarf, the initial length is 12 bytes, because of the |
| // 0xffffffff at the start. |
| if (header_.offset_size == 8) |
| lengthstart += 12; |
| else |
| lengthstart += 4; |
| |
| while (lineptr < lengthstart + header_.total_length) |
| { |
| ResetLineStateMachine(&lsm, header_.default_is_stmt); |
| while (!lsm.end_sequence) |
| { |
| size_t oplength; |
| bool add_line = this->process_one_opcode(lineptr, &lsm, &oplength); |
| if (add_line |
| && (shndx == -1U || lsm.shndx == -1U || shndx == lsm.shndx)) |
| { |
| Offset_to_lineno_entry entry |
| = { lsm.address, this->current_header_index_, |
| lsm.file_num, true, lsm.line_num }; |
| std::vector<Offset_to_lineno_entry>& |
| map(this->line_number_map_[lsm.shndx]); |
| // If we see two consecutive entries with the same |
| // offset and a real line number, then mark the first |
| // one as non-canonical. |
| if (!map.empty() |
| && (map.back().offset == static_cast<off_t>(lsm.address)) |
| && lsm.line_num != -1 |
| && map.back().line_num != -1) |
| map.back().last_line_for_offset = false; |
| map.push_back(entry); |
| } |
| lineptr += oplength; |
| } |
| } |
| |
| return lengthstart + header_.total_length; |
| } |
| |
| // Looks in the symtab to see what section a symbol is in. |
| |
| template<int size, bool big_endian> |
| unsigned int |
| Sized_dwarf_line_info<size, big_endian>::symbol_section( |
| Object* object, |
| unsigned int sym, |
| typename elfcpp::Elf_types<size>::Elf_Addr* value, |
| bool* is_ordinary) |
| { |
| const int symsize = elfcpp::Elf_sizes<size>::sym_size; |
| gold_assert(sym * symsize < this->symtab_buffer_size_); |
| elfcpp::Sym<size, big_endian> elfsym(this->symtab_buffer_ + sym * symsize); |
| *value = elfsym.get_st_value(); |
| return object->adjust_sym_shndx(sym, elfsym.get_st_shndx(), is_ordinary); |
| } |
| |
| // Read the relocations into a Reloc_map. |
| |
| template<int size, bool big_endian> |
| void |
| Sized_dwarf_line_info<size, big_endian>::read_relocs(Object* object) |
| { |
| if (this->symtab_buffer_ == NULL) |
| return; |
| |
| typename elfcpp::Elf_types<size>::Elf_Addr value; |
| off_t reloc_offset; |
| while ((reloc_offset = this->track_relocs_.next_offset()) != -1) |
| { |
| const unsigned int sym = this->track_relocs_.next_symndx(); |
| |
| bool is_ordinary; |
| const unsigned int shndx = this->symbol_section(object, sym, &value, |
| &is_ordinary); |
| |
| // There is no reason to record non-ordinary section indexes, or |
| // SHN_UNDEF, because they will never match the real section. |
| if (is_ordinary && shndx != elfcpp::SHN_UNDEF) |
| { |
| value += this->track_relocs_.next_addend(); |
| this->reloc_map_[reloc_offset] = std::make_pair(shndx, value); |
| } |
| |
| this->track_relocs_.advance(reloc_offset + 1); |
| } |
| } |
| |
| // Read the line number info. |
| |
| template<int size, bool big_endian> |
| void |
| Sized_dwarf_line_info<size, big_endian>::read_line_mappings(Object* object, |
| unsigned int shndx) |
| { |
| gold_assert(this->data_valid_ == true); |
| |
| this->read_relocs(object); |
| while (this->buffer_ < this->buffer_end_) |
| { |
| const unsigned char* lineptr = this->buffer_; |
| lineptr = this->read_header_prolog(lineptr); |
| lineptr = this->read_header_tables(lineptr); |
| lineptr = this->read_lines(lineptr, shndx); |
| this->buffer_ = lineptr; |
| } |
| |
| // Sort the lines numbers, so addr2line can use binary search. |
| for (typename Lineno_map::iterator it = line_number_map_.begin(); |
| it != line_number_map_.end(); |
| ++it) |
| // Each vector needs to be sorted by offset. |
| std::sort(it->second.begin(), it->second.end()); |
| } |
| |
| // Some processing depends on whether the input is a .o file or not. |
| // For instance, .o files have relocs, and have .debug_lines |
| // information on a per section basis. .so files, on the other hand, |
| // lack relocs, and offsets are unique, so we can ignore the section |
| // information. |
| |
| template<int size, bool big_endian> |
| bool |
| Sized_dwarf_line_info<size, big_endian>::input_is_relobj() |
| { |
| // Only .o files have relocs and the symtab buffer that goes with them. |
| return this->symtab_buffer_ != NULL; |
| } |
| |
| // Given an Offset_to_lineno_entry vector, and an offset, figure out |
| // if the offset points into a function according to the vector (see |
| // comments below for the algorithm). If it does, return an iterator |
| // into the vector that points to the line-number that contains that |
| // offset. If not, it returns vector::end(). |
| |
| static std::vector<Offset_to_lineno_entry>::const_iterator |
| offset_to_iterator(const std::vector<Offset_to_lineno_entry>* offsets, |
| off_t offset) |
| { |
| const Offset_to_lineno_entry lookup_key = { offset, 0, 0, true, 0 }; |
| |
| // lower_bound() returns the smallest offset which is >= lookup_key. |
| // If no offset in offsets is >= lookup_key, returns end(). |
| std::vector<Offset_to_lineno_entry>::const_iterator it |
| = std::lower_bound(offsets->begin(), offsets->end(), lookup_key); |
| |
| // This code is easiest to understand with a concrete example. |
| // Here's a possible offsets array: |
| // {{offset = 3211, header_num = 0, file_num = 1, last, line_num = 16}, // 0 |
| // {offset = 3224, header_num = 0, file_num = 1, last, line_num = 20}, // 1 |
| // {offset = 3226, header_num = 0, file_num = 1, last, line_num = 22}, // 2 |
| // {offset = 3231, header_num = 0, file_num = 1, last, line_num = 25}, // 3 |
| // {offset = 3232, header_num = 0, file_num = 1, last, line_num = -1}, // 4 |
| // {offset = 3232, header_num = 0, file_num = 1, last, line_num = 65}, // 5 |
| // {offset = 3235, header_num = 0, file_num = 1, last, line_num = 66}, // 6 |
| // {offset = 3236, header_num = 0, file_num = 1, last, line_num = -1}, // 7 |
| // {offset = 5764, header_num = 0, file_num = 1, last, line_num = 48}, // 8 |
| // {offset = 5764, header_num = 0, file_num = 1,!last, line_num = 47}, // 9 |
| // {offset = 5765, header_num = 0, file_num = 1, last, line_num = 49}, // 10 |
| // {offset = 5767, header_num = 0, file_num = 1, last, line_num = 50}, // 11 |
| // {offset = 5768, header_num = 0, file_num = 1, last, line_num = 51}, // 12 |
| // {offset = 5773, header_num = 0, file_num = 1, last, line_num = -1}, // 13 |
| // {offset = 5787, header_num = 1, file_num = 1, last, line_num = 19}, // 14 |
| // {offset = 5790, header_num = 1, file_num = 1, last, line_num = 20}, // 15 |
| // {offset = 5793, header_num = 1, file_num = 1, last, line_num = 67}, // 16 |
| // {offset = 5793, header_num = 1, file_num = 1, last, line_num = -1}, // 17 |
| // {offset = 5793, header_num = 1, file_num = 1,!last, line_num = 66}, // 18 |
| // {offset = 5795, header_num = 1, file_num = 1, last, line_num = 68}, // 19 |
| // {offset = 5798, header_num = 1, file_num = 1, last, line_num = -1}, // 20 |
| // The entries with line_num == -1 mark the end of a function: the |
| // associated offset is one past the last instruction in the |
| // function. This can correspond to the beginning of the next |
| // function (as is true for offset 3232); alternately, there can be |
| // a gap between the end of one function and the start of the next |
| // (as is true for some others, most obviously from 3236->5764). |
| // |
| // Case 1: lookup_key has offset == 10. lower_bound returns |
| // offsets[0]. Since it's not an exact match and we're |
| // at the beginning of offsets, we return end() (invalid). |
| // Case 2: lookup_key has offset 10000. lower_bound returns |
| // offset[21] (end()). We return end() (invalid). |
| // Case 3: lookup_key has offset == 3211. lower_bound matches |
| // offsets[0] exactly, and that's the entry we return. |
| // Case 4: lookup_key has offset == 3232. lower_bound returns |
| // offsets[4]. That's an exact match, but indicates |
| // end-of-function. We check if offsets[5] is also an |
| // exact match but not end-of-function. It is, so we |
| // return offsets[5]. |
| // Case 5: lookup_key has offset == 3214. lower_bound returns |
| // offsets[1]. Since it's not an exact match, we back |
| // up to the offset that's < lookup_key, offsets[0]. |
| // We note offsets[0] is a valid entry (not end-of-function), |
| // so that's the entry we return. |
| // Case 6: lookup_key has offset == 4000. lower_bound returns |
| // offsets[8]. Since it's not an exact match, we back |
| // up to offsets[7]. Since offsets[7] indicates |
| // end-of-function, we know lookup_key is between |
| // functions, so we return end() (not a valid offset). |
| // Case 7: lookup_key has offset == 5794. lower_bound returns |
| // offsets[19]. Since it's not an exact match, we back |
| // up to offsets[16]. Note we back up to the *first* |
| // entry with offset 5793, not just offsets[19-1]. |
| // We note offsets[16] is a valid entry, so we return it. |
| // If offsets[16] had had line_num == -1, we would have |
| // checked offsets[17]. The reason for this is that |
| // 16 and 17 can be in an arbitrary order, since we sort |
| // only by offset and last_line_for_offset. (Note it |
| // doesn't help to use line_number as a tertiary sort key, |
| // since sometimes we want the -1 to be first and sometimes |
| // we want it to be last.) |
| |
| // This deals with cases (1) and (2). |
| if ((it == offsets->begin() && offset < it->offset) |
| || it == offsets->end()) |
| return offsets->end(); |
| |
| // This deals with cases (3) and (4). |
| if (offset == it->offset) |
| { |
| while (it != offsets->end() |
| && it->offset == offset |
| && it->line_num == -1) |
| ++it; |
| if (it == offsets->end() || it->offset != offset) |
| return offsets->end(); |
| else |
| return it; |
| } |
| |
| // This handles the first part of case (7) -- we back up to the |
| // *first* entry that has the offset that's behind us. |
| gold_assert(it != offsets->begin()); |
| std::vector<Offset_to_lineno_entry>::const_iterator range_end = it; |
| --it; |
| const off_t range_value = it->offset; |
| while (it != offsets->begin() && (it-1)->offset == range_value) |
| --it; |
| |
| // This handles cases (5), (6), and (7): if any entry in the |
| // equal_range [it, range_end) has a line_num != -1, it's a valid |
| // match. If not, we're not in a function. The line number we saw |
| // last for an offset will be sorted first, so it'll get returned if |
| // it's present. |
| for (; it != range_end; ++it) |
| if (it->line_num != -1) |
| return it; |
| return offsets->end(); |
| } |
| |
| // Returns the canonical filename:lineno for the address passed in. |
| // If other_lines is not NULL, appends the non-canonical lines |
| // assigned to the same address. |
| |
| template<int size, bool big_endian> |
| std::string |
| Sized_dwarf_line_info<size, big_endian>::do_addr2line( |
| unsigned int shndx, |
| off_t offset, |
| std::vector<std::string>* other_lines) |
| { |
| if (this->data_valid_ == false) |
| return ""; |
| |
| const std::vector<Offset_to_lineno_entry>* offsets; |
| // If we do not have reloc information, then our input is a .so or |
| // some similar data structure where all the information is held in |
| // the offset. In that case, we ignore the input shndx. |
| if (this->input_is_relobj()) |
| offsets = &this->line_number_map_[shndx]; |
| else |
| offsets = &this->line_number_map_[-1U]; |
| if (offsets->empty()) |
| return ""; |
| |
| typename std::vector<Offset_to_lineno_entry>::const_iterator it |
| = offset_to_iterator(offsets, offset); |
| if (it == offsets->end()) |
| return ""; |
| |
| std::string result = this->format_file_lineno(*it); |
| if (other_lines != NULL) |
| for (++it; it != offsets->end() && it->offset == offset; ++it) |
| { |
| if (it->line_num == -1) |
| continue; // The end of a previous function. |
| other_lines->push_back(this->format_file_lineno(*it)); |
| } |
| return result; |
| } |
| |
| // Convert the file_num + line_num into a string. |
| |
| template<int size, bool big_endian> |
| std::string |
| Sized_dwarf_line_info<size, big_endian>::format_file_lineno( |
| const Offset_to_lineno_entry& loc) const |
| { |
| std::string ret; |
| |
| gold_assert(loc.header_num < static_cast<int>(this->files_.size())); |
| gold_assert(loc.file_num |
| < static_cast<int>(this->files_[loc.header_num].size())); |
| const std::pair<int, std::string>& filename_pair |
| = this->files_[loc.header_num][loc.file_num]; |
| const std::string& filename = filename_pair.second; |
| |
| gold_assert(loc.header_num < static_cast<int>(this->directories_.size())); |
| gold_assert(filename_pair.first |
| < static_cast<int>(this->directories_[loc.header_num].size())); |
| const std::string& dirname |
| = this->directories_[loc.header_num][filename_pair.first]; |
| |
| if (!dirname.empty()) |
| { |
| ret += dirname; |
| ret += "/"; |
| } |
| ret += filename; |
| if (ret.empty()) |
| ret = "(unknown)"; |
| |
| char buffer[64]; // enough to hold a line number |
| snprintf(buffer, sizeof(buffer), "%d", loc.line_num); |
| ret += ":"; |
| ret += buffer; |
| |
| return ret; |
| } |
| |
| // Dwarf_line_info routines. |
| |
| static unsigned int next_generation_count = 0; |
| |
| struct Addr2line_cache_entry |
| { |
| Object* object; |
| unsigned int shndx; |
| Dwarf_line_info* dwarf_line_info; |
| unsigned int generation_count; |
| unsigned int access_count; |
| |
| Addr2line_cache_entry(Object* o, unsigned int s, Dwarf_line_info* d) |
| : object(o), shndx(s), dwarf_line_info(d), |
| generation_count(next_generation_count), access_count(0) |
| { |
| if (next_generation_count < (1U << 31)) |
| ++next_generation_count; |
| } |
| }; |
| // We expect this cache to be small, so don't bother with a hashtable |
| // or priority queue or anything: just use a simple vector. |
| static std::vector<Addr2line_cache_entry> addr2line_cache; |
| |
| std::string |
| Dwarf_line_info::one_addr2line(Object* object, |
| unsigned int shndx, off_t offset, |
| size_t cache_size, |
| std::vector<std::string>* other_lines) |
| { |
| Dwarf_line_info* lineinfo = NULL; |
| std::vector<Addr2line_cache_entry>::iterator it; |
| |
| // First, check the cache. If we hit, update the counts. |
| for (it = addr2line_cache.begin(); it != addr2line_cache.end(); ++it) |
| { |
| if (it->object == object && it->shndx == shndx) |
| { |
| lineinfo = it->dwarf_line_info; |
| it->generation_count = next_generation_count; |
| // We cap generation_count at 2^31 -1 to avoid overflow. |
| if (next_generation_count < (1U << 31)) |
| ++next_generation_count; |
| // We cap access_count at 31 so 2^access_count doesn't overflow |
| if (it->access_count < 31) |
| ++it->access_count; |
| break; |
| } |
| } |
| |
| // If we don't hit the cache, create a new object and insert into the |
| // cache. |
| if (lineinfo == NULL) |
| { |
| switch (parameters->size_and_endianness()) |
| { |
| #ifdef HAVE_TARGET_32_LITTLE |
| case Parameters::TARGET_32_LITTLE: |
| lineinfo = new Sized_dwarf_line_info<32, false>(object, shndx); break; |
| #endif |
| #ifdef HAVE_TARGET_32_BIG |
| case Parameters::TARGET_32_BIG: |
| lineinfo = new Sized_dwarf_line_info<32, true>(object, shndx); break; |
| #endif |
| #ifdef HAVE_TARGET_64_LITTLE |
| case Parameters::TARGET_64_LITTLE: |
| lineinfo = new Sized_dwarf_line_info<64, false>(object, shndx); break; |
| #endif |
| #ifdef HAVE_TARGET_64_BIG |
| case Parameters::TARGET_64_BIG: |
| lineinfo = new Sized_dwarf_line_info<64, true>(object, shndx); break; |
| #endif |
| default: |
| gold_unreachable(); |
| } |
| addr2line_cache.push_back(Addr2line_cache_entry(object, shndx, lineinfo)); |
| } |
| |
| // Now that we have our object, figure out the answer |
| std::string retval = lineinfo->addr2line(shndx, offset, other_lines); |
| |
| // Finally, if our cache has grown too big, delete old objects. We |
| // assume the common (probably only) case is deleting only one object. |
| // We use a pretty simple scheme to evict: function of LRU and MFU. |
| while (addr2line_cache.size() > cache_size) |
| { |
| unsigned int lowest_score = ~0U; |
| std::vector<Addr2line_cache_entry>::iterator lowest |
| = addr2line_cache.end(); |
| for (it = addr2line_cache.begin(); it != addr2line_cache.end(); ++it) |
| { |
| const unsigned int score = (it->generation_count |
| + (1U << it->access_count)); |
| if (score < lowest_score) |
| { |
| lowest_score = score; |
| lowest = it; |
| } |
| } |
| if (lowest != addr2line_cache.end()) |
| { |
| delete lowest->dwarf_line_info; |
| addr2line_cache.erase(lowest); |
| } |
| } |
| |
| return retval; |
| } |
| |
| void |
| Dwarf_line_info::clear_addr2line_cache() |
| { |
| for (std::vector<Addr2line_cache_entry>::iterator it = addr2line_cache.begin(); |
| it != addr2line_cache.end(); |
| ++it) |
| delete it->dwarf_line_info; |
| addr2line_cache.clear(); |
| } |
| |
| #ifdef HAVE_TARGET_32_LITTLE |
| template |
| class Sized_dwarf_line_info<32, false>; |
| #endif |
| |
| #ifdef HAVE_TARGET_32_BIG |
| template |
| class Sized_dwarf_line_info<32, true>; |
| #endif |
| |
| #ifdef HAVE_TARGET_64_LITTLE |
| template |
| class Sized_dwarf_line_info<64, false>; |
| #endif |
| |
| #ifdef HAVE_TARGET_64_BIG |
| template |
| class Sized_dwarf_line_info<64, true>; |
| #endif |
| |
| } // End namespace gold. |