#!/bin/sh

# Copyright (c) 2012 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
#
# Copyright (C) 2010 Free Software Foundation, Inc.
# 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, see <http://www.gnu.org/licenses/>.

# This is a modification of gdb-add-index that recursively adds an index
# to the shared libraries dependencies from the same build.

target="$1"
target_dir="${target%/*}"

OLDIFS=$IFS
IFS=$'\n'

shared_libraries=$(
    ldd -d "$target" | grep "$target_dir" | cut -d '>' -f2 | cut -d ' ' -f2
    )

# This function is basically the RedHat's gdb-add-index script and is why
# we have the FSF copyright above.
function index_one_file {
  local file="$1"
  local dir="${file%/*}"

  # We don't care if gdb gives an error.
  gdb -nx --batch-silent -ex "file $file" -ex "save gdb-index $dir"

  if test -f "${file}.gdb-index"; then
    objcopy --add-section .gdb_index="${file}.gdb-index" --set-section-flags \
        .gdb_index=readonly "$file" "$file"
    rm -f "${file}.gdb-index"
  fi
}

function maybe_index {
  readelf -e "$1" | grep '.gdb_index' > /dev/null 2>&1
  if [[ "$?" != 0 ]]; then
    echo "Adding .gdb_index to $1"
    index_one_file "$1"
  else
    echo "Skipping $1 (already has .gdb_index)"
  fi
}

maybe_index "$target"
for lib in $shared_libraries; do
  maybe_index "$lib"
done