URL
https://opencores.org/ocsvn/open8_urisc/open8_urisc/trunk
Subversion Repositories open8_urisc
[/] [open8_urisc/] [trunk/] [gnu/] [binutils/] [gold/] [dwarf_reader.cc] - Rev 89
Go to most recent revision | Compare with Previous | Blame | View Log
// 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.resize(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. 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.
Go to most recent revision | Compare with Previous | Blame | View Log