--- /dev/null
+// dwarf_reader.cc -- parse dwarf2/3 debug information
+
+// Copyright 2007, 2008, 2009 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"
+
+namespace gold {
+
+// Read an unsigned LEB128 number. Each byte contains 7 bits of
+// information, plus one bit saying whether the number continues or
+// not.
+
+uint64_t
+read_unsigned_LEB_128(const unsigned char* buffer, size_t* len)
+{
+ uint64_t result = 0;
+ size_t num_read = 0;
+ unsigned int shift = 0;
+ unsigned char byte;
+
+ do
+ {
+ if (num_read >= 64 / 7)
+ {
+ gold_warning(_("Unusually large LEB128 decoded, "
+ "debug information may be corrupted"));
+ break;
+ }
+ byte = *buffer++;
+ num_read++;
+ result |= (static_cast<uint64_t>(byte & 0x7f)) << shift;
+ shift += 7;
+ }
+ while (byte & 0x80);
+
+ *len = num_read;
+
+ return result;
+}
+
+// Read a signed LEB128 number. These are like regular LEB128
+// numbers, except the last byte may have a sign bit set.
+
+int64_t
+read_signed_LEB_128(const unsigned char* buffer, size_t* len)
+{
+ int64_t result = 0;
+ int shift = 0;
+ size_t num_read = 0;
+ unsigned char byte;
+
+ do
+ {
+ if (num_read >= 64 / 7)
+ {
+ gold_warning(_("Unusually large LEB128 decoded, "
+ "debug information may be corrupted"));
+ break;
+ }
+ byte = *buffer++;
+ num_read++;
+ result |= (static_cast<uint64_t>(byte & 0x7f) << shift);
+ shift += 7;
+ }
+ while (byte & 0x80);
+
+ if ((shift < 8 * static_cast<int>(sizeof(result))) && (byte & 0x40))
+ result |= -((static_cast<int64_t>(1)) << shift);
+ *len = num_read;
+ return result;
+}
+
+// This is the format of a DWARF2/3 line state machine that we process
+// opcodes using. There is no need for anything outside the lineinfo
+// processor to know how this works.
+
+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 = 0; debug_shndx < object->shnum(); ++debug_shndx)
+ // FIXME: do this more efficiently: section_name() isn't super-fast
+ if (object->section_name(debug_shndx) == ".debug_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;
+
+ // 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);
+ 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
+ = reloc_map_.find(start - this->buffer_);
+ if (it != reloc_map_.end())
+ {
+ // value + addend.
+ 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, lsm.line_num };
+ line_number_map_[lsm.shndx].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)
+ 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, 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, line_num = 16}, // 0
+ // {offset = 3224, header_num = 0, file_num = 1, line_num = 20}, // 1
+ // {offset = 3226, header_num = 0, file_num = 1, line_num = 22}, // 2
+ // {offset = 3231, header_num = 0, file_num = 1, line_num = 25}, // 3
+ // {offset = 3232, header_num = 0, file_num = 1, line_num = -1}, // 4
+ // {offset = 3232, header_num = 0, file_num = 1, line_num = 65}, // 5
+ // {offset = 3235, header_num = 0, file_num = 1, line_num = 66}, // 6
+ // {offset = 3236, header_num = 0, file_num = 1, line_num = -1}, // 7
+ // {offset = 5764, header_num = 0, file_num = 1, line_num = 47}, // 8
+ // {offset = 5765, header_num = 0, file_num = 1, line_num = 48}, // 9
+ // {offset = 5767, header_num = 0, file_num = 1, line_num = 49}, // 10
+ // {offset = 5768, header_num = 0, file_num = 1, line_num = 50}, // 11
+ // {offset = 5773, header_num = 0, file_num = 1, line_num = -1}, // 12
+ // {offset = 5787, header_num = 1, file_num = 1, line_num = 19}, // 13
+ // {offset = 5790, header_num = 1, file_num = 1, line_num = 20}, // 14
+ // {offset = 5793, header_num = 1, file_num = 1, line_num = 67}, // 15
+ // {offset = 5793, header_num = 1, file_num = 1, line_num = -1}, // 16
+ // {offset = 5795, header_num = 1, file_num = 1, line_num = 68}, // 17
+ // {offset = 5798, header_num = 1, file_num = 1, line_num = -1}, // 18
+ // 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[19] (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[17]. Since it's not an exact match, we back
+ // up to offsets[15]. Note we back up to the *first*
+ // entry with offset 5793, not just offsets[17-1].
+ // We note offsets[15] is a valid entry, so we return it.
+ // If offsets[15] had had line_num == -1, we would have
+ // checked offsets[16]. The reason for this is that
+ // 15 and 16 can be in an arbitrary order, since we sort
+ // only by offset. (Note it doesn't help to use line_number
+ // as a secondary 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.
+ for (; it != range_end; ++it)
+ if (it->line_num != -1)
+ return it;
+ return offsets->end();
+}
+
+// Return a string for a file name and line number.
+
+template<int size, bool big_endian>
+std::string
+Sized_dwarf_line_info<size, big_endian>::do_addr2line(unsigned int shndx,
+ off_t offset)
+{
+ 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 "";
+
+ // Convert the file_num + line_num into a string.
+ std::string ret;
+
+ gold_assert(it->header_num < static_cast<int>(this->files_.size()));
+ gold_assert(it->file_num
+ < static_cast<int>(this->files_[it->header_num].size()));
+ const std::pair<int, std::string>& filename_pair
+ = this->files_[it->header_num][it->file_num];
+ const std::string& filename = filename_pair.second;
+
+ gold_assert(it->header_num < static_cast<int>(this->directories_.size()));
+ gold_assert(filename_pair.first
+ < static_cast<int>(this->directories_[it->header_num].size()));
+ const std::string& dirname
+ = this->directories_[it->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", it->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)
+{
+ 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);
+
+ // 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.
projects / msp430-binutils.git / blobdiff