James Robinson | 646469d | 2014-10-03 15:33:28 -0700 | [diff] [blame] | 1 | #!/bin/bash |
| 2 | # Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| 3 | # Use of this source code is governed by a BSD-style license that can be |
| 4 | # found in the LICENSE file. |
| 5 | # |
| 6 | # Saves the gdb index for a given binary and its shared library dependencies. |
| 7 | # |
| 8 | # This will run gdb index in parallel on a number of binaries using SIGUSR1 |
| 9 | # as the communication mechanism to simulate a semaphore. Because of the |
| 10 | # nature of this technique, using "set -e" is very difficult. The SIGUSR1 |
| 11 | # terminates a "wait" with an error which we need to interpret. |
| 12 | # |
| 13 | # When modifying this code, most of the real logic is in the index_one_file |
| 14 | # function. The rest is cleanup + sempahore plumbing. |
| 15 | |
| 16 | # Cleanup temp directory and ensure all child jobs are dead-dead. |
| 17 | function on_exit { |
| 18 | trap "" EXIT USR1 # Avoid reentrancy. |
| 19 | |
| 20 | local jobs=$(jobs -p) |
| 21 | if [ -n "$jobs" ]; then |
| 22 | echo -n "Killing outstanding index jobs..." |
| 23 | kill -KILL $(jobs -p) |
| 24 | wait |
| 25 | echo "done" |
| 26 | fi |
| 27 | |
| 28 | if [ -f "$DIRECTORY" ]; then |
| 29 | echo -n "Removing temp directory $DIRECTORY..." |
| 30 | rm -rf $DIRECTORY |
| 31 | echo done |
| 32 | fi |
| 33 | } |
| 34 | |
| 35 | # Add index to one binary. |
| 36 | function index_one_file { |
| 37 | local file=$1 |
| 38 | local basename=$(basename "$file") |
| 39 | local should_index="${SHOULD_INDEX}" |
| 40 | |
James Robinson | d753aca | 2015-01-12 13:07:20 -0800 | [diff] [blame] | 41 | local readelf_out=$(${TOOLCHAIN_PREFIX}readelf -S "$file") |
James Robinson | 646469d | 2014-10-03 15:33:28 -0700 | [diff] [blame] | 42 | if [[ $readelf_out =~ "gdb_index" ]]; then |
| 43 | if [ "${REMOVE_INDEX}" = 1 ]; then |
James Robinson | d753aca | 2015-01-12 13:07:20 -0800 | [diff] [blame] | 44 | ${TOOLCHAIN_PREFIX}objcopy --remove-section .gdb_index "$file" |
James Robinson | 646469d | 2014-10-03 15:33:28 -0700 | [diff] [blame] | 45 | echo "Removed index from $basename." |
| 46 | else |
| 47 | echo "Skipped $basename -- already contains index." |
| 48 | should_index=0 |
| 49 | fi |
| 50 | fi |
| 51 | |
| 52 | if [ "${should_index}" = 1 ]; then |
| 53 | local start=$(date +"%s%N") |
| 54 | echo "Adding index to $basename..." |
| 55 | |
James Robinson | d753aca | 2015-01-12 13:07:20 -0800 | [diff] [blame] | 56 | ${TOOLCHAIN_PREFIX}gdb -batch "$file" -ex "save gdb-index $DIRECTORY" \ |
| 57 | -ex "quit" |
James Robinson | 646469d | 2014-10-03 15:33:28 -0700 | [diff] [blame] | 58 | local index_file="$DIRECTORY/$basename.gdb-index" |
| 59 | if [ -f "$index_file" ]; then |
James Robinson | d753aca | 2015-01-12 13:07:20 -0800 | [diff] [blame] | 60 | ${TOOLCHAIN_PREFIX}objcopy --add-section .gdb_index="$index_file" \ |
James Robinson | 646469d | 2014-10-03 15:33:28 -0700 | [diff] [blame] | 61 | --set-section-flags .gdb_index=readonly "$file" "$file" |
| 62 | local finish=$(date +"%s%N") |
James Robinson | d753aca | 2015-01-12 13:07:20 -0800 | [diff] [blame] | 63 | local elapsed=$(((finish - start)/1000000)) |
| 64 | echo " ...$basename indexed. [${elapsed}ms]" |
James Robinson | 646469d | 2014-10-03 15:33:28 -0700 | [diff] [blame] | 65 | else |
| 66 | echo " ...$basename unindexable." |
| 67 | fi |
| 68 | fi |
| 69 | } |
| 70 | |
| 71 | # Functions that when combined, concurrently index all files in FILES_TO_INDEX |
| 72 | # array. The global FILES_TO_INDEX is declared in the main body of the script. |
| 73 | function async_index { |
| 74 | # Start a background subshell to run the index command. |
| 75 | { |
| 76 | index_one_file $1 |
| 77 | kill -SIGUSR1 $$ # $$ resolves to the parent script. |
| 78 | exit 129 # See comment above wait loop at bottom. |
| 79 | } & |
| 80 | } |
| 81 | |
| 82 | CUR_FILE_NUM=0 |
| 83 | function index_next { |
| 84 | if (( CUR_FILE_NUM >= ${#FILES_TO_INDEX[@]} )); then |
| 85 | return |
| 86 | fi |
| 87 | |
| 88 | async_index "${FILES_TO_INDEX[CUR_FILE_NUM]}" |
| 89 | ((CUR_FILE_NUM += 1)) || true |
| 90 | } |
| 91 | |
| 92 | |
| 93 | ######## |
| 94 | ### Main body of the script. |
| 95 | |
| 96 | REMOVE_INDEX=0 |
| 97 | SHOULD_INDEX=1 |
| 98 | while getopts ":f:r" opt; do |
| 99 | case $opt in |
| 100 | f) |
| 101 | REMOVE_INDEX=1 |
| 102 | shift |
| 103 | ;; |
| 104 | r) |
| 105 | REMOVE_INDEX=1 |
| 106 | SHOULD_INDEX=0 |
| 107 | shift |
| 108 | ;; |
| 109 | *) |
| 110 | echo "Invalid option: -$OPTARG" >&2 |
| 111 | ;; |
| 112 | esac |
| 113 | done |
| 114 | |
| 115 | if [[ ! $# == 1 ]]; then |
| 116 | echo "Usage: $0 [-f] [-r] path-to-binary" |
| 117 | echo " -f forces replacement of an existing index." |
| 118 | echo " -r removes the index section." |
| 119 | exit 1 |
| 120 | fi |
| 121 | |
| 122 | FILENAME="$1" |
| 123 | if [[ ! -f "$FILENAME" ]]; then |
| 124 | echo "Path $FILENAME does not exist." |
| 125 | exit 1 |
| 126 | fi |
| 127 | |
| 128 | # Ensure we cleanup on on exit. |
| 129 | trap on_exit EXIT |
| 130 | |
| 131 | # We're good to go! Create temp directory for index files. |
| 132 | DIRECTORY=$(mktemp -d) |
| 133 | echo "Made temp directory $DIRECTORY." |
| 134 | |
| 135 | # Create array with the filename and all shared libraries that |
| 136 | # have the same dirname. The dirname is a signal that these |
| 137 | # shared libraries were part of the same build as the binary. |
| 138 | declare -a FILES_TO_INDEX=($FILENAME |
| 139 | $(ldd "$FILENAME" 2>/dev/null \ |
| 140 | | grep $(dirname "$FILENAME") \ |
| 141 | | sed "s/.*[ \t]\(.*\) (.*/\1/") |
| 142 | ) |
| 143 | |
| 144 | # Start concurrent indexing. |
| 145 | trap index_next USR1 |
| 146 | |
| 147 | # 4 is an arbitrary default. When changing, remember we are likely IO bound |
| 148 | # so basing this off the number of cores is not sensible. |
| 149 | INDEX_TASKS=${INDEX_TASKS:-4} |
| 150 | for ((i=0;i<${INDEX_TASKS};i++)); do |
| 151 | index_next |
| 152 | done |
| 153 | |
| 154 | # Do a wait loop. Bash waits that terminate due a trap have an exit |
| 155 | # code > 128. We also ensure that our subshell's "normal" exit occurs with |
| 156 | # an exit code > 128. This allows us to do consider a > 128 exit code as |
| 157 | # an indication that the loop should continue. Unfortunately, it also means |
| 158 | # we cannot use set -e since technically the "wait" is failing. |
| 159 | wait |
| 160 | while (( $? > 128 )); do |
| 161 | wait |
| 162 | done |