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 function usage_exit { 17 echo "Usage: $0 [-f] [-r] [-n] <paths-to-binaries>..." 18 echo " -f forces replacement of an existing index." 19 echo " -r removes the index section." 20 echo " -n don't extract the dependencies of each binary with lld." 21 echo " e.g., $0 -n out/Debug/lib.unstripped/lib*" 22 echo 23 echo " Set TOOLCHAIN_PREFIX to use a non-default set of binutils." 24 exit 1 25 } 26 27 # Cleanup temp directory and ensure all child jobs are dead-dead. 28 function on_exit { 29 trap "" EXIT USR1 # Avoid reentrancy. 30 31 local jobs=$(jobs -p) 32 if [ -n "$jobs" ]; then 33 echo -n "Killing outstanding index jobs..." 34 kill -KILL $(jobs -p) 35 wait 36 echo "done" 37 fi 38 39 if [ -f "$directory" ]; then 40 echo -n "Removing temp directory $directory..." 41 rm -rf "$directory" 42 echo done 43 fi 44 } 45 46 # Add index to one binary. 47 function index_one_file { 48 local file=$1 49 local basename=$(basename "$file") 50 local should_index_this_file="${should_index}" 51 52 local readelf_out=$(${TOOLCHAIN_PREFIX}readelf -S "$file") 53 if [[ $readelf_out =~ "gdb_index" ]]; then 54 if $remove_index; then 55 ${TOOLCHAIN_PREFIX}objcopy --remove-section .gdb_index "$file" 56 echo "Removed index from $basename." 57 else 58 echo "Skipped $basename -- already contains index." 59 should_index_this_file=false 60 fi 61 fi 62 63 if $should_index_this_file; then 64 local start=$(date +"%s%N") 65 echo "Adding index to $basename..." 66 67 ${TOOLCHAIN_PREFIX}gdb -batch "$file" -ex "save gdb-index $directory" \ 68 -ex "quit" 69 local index_file="$directory/$basename.gdb-index" 70 if [ -f "$index_file" ]; then 71 ${TOOLCHAIN_PREFIX}objcopy --add-section .gdb_index="$index_file" \ 72 --set-section-flags .gdb_index=readonly "$file" "$file" 73 local finish=$(date +"%s%N") 74 local elapsed=$(((finish - start) / 1000000)) 75 echo " ...$basename indexed. [${elapsed}ms]" 76 else 77 echo " ...$basename unindexable." 78 fi 79 fi 80 } 81 82 # Functions that when combined, concurrently index all files in FILES_TO_INDEX 83 # array. The global FILES_TO_INDEX is declared in the main body of the script. 84 function async_index { 85 # Start a background subshell to run the index command. 86 { 87 index_one_file $1 88 kill -SIGUSR1 $$ # $$ resolves to the parent script. 89 exit 129 # See comment above wait loop at bottom. 90 } & 91 } 92 93 cur_file_num=0 94 function index_next { 95 if ((cur_file_num >= ${#files_to_index[@]})); then 96 return 97 fi 98 99 async_index "${files_to_index[cur_file_num]}" 100 ((cur_file_num += 1)) || true 101 } 102 103 ######## 104 ### Main body of the script. 105 106 remove_index=false 107 should_index=true 108 should_index_deps=true 109 files_to_index=() 110 while (($# > 0)); do 111 case "$1" in 112 -h) 113 usage_exit 114 ;; 115 -f) 116 remove_index=true 117 ;; 118 -r) 119 remove_index=true 120 should_index=false 121 ;; 122 -n) 123 should_index_deps=false 124 ;; 125 -*) 126 echo "Invalid option: $1" >&2 127 usage_exit 128 ;; 129 *) 130 if [[ ! -f "$1" ]]; then 131 echo "Path $1 does not exist." 132 exit 1 133 fi 134 files_to_index+=("$1") 135 ;; 136 esac 137 shift 138 done 139 140 if ((${#files_to_index[@]} == 0)); then 141 usage_exit 142 fi 143 144 dependencies=() 145 if $should_index_deps; then 146 for file in "${files_to_index[@]}"; do 147 # Append the shared library dependencies of this file that 148 # have the same dirname. The dirname is a signal that these 149 # shared libraries were part of the same build as the binary. 150 dependencies+=( \ 151 $(ldd "$file" 2>/dev/null \ 152 | grep $(dirname "$file") \ 153 | sed "s/.*[ \t]\(.*\) (.*/\1/") \ 154 ) 155 done 156 fi 157 files_to_index+=("${dependencies[@]}") 158 159 # Ensure we cleanup on on exit. 160 trap on_exit EXIT INT 161 162 # We're good to go! Create temp directory for index files. 163 directory=$(mktemp -d) 164 echo "Made temp directory $directory." 165 166 # Start concurrent indexing. 167 trap index_next USR1 168 169 # 4 is an arbitrary default. When changing, remember we are likely IO bound 170 # so basing this off the number of cores is not sensible. 171 index_tasks=${INDEX_TASKS:-4} 172 for ((i = 0; i < index_tasks; i++)); do 173 index_next 174 done 175 176 # Do a wait loop. Bash waits that terminate due a trap have an exit 177 # code > 128. We also ensure that our subshell's "normal" exit occurs with 178 # an exit code > 128. This allows us to do consider a > 128 exit code as 179 # an indication that the loop should continue. Unfortunately, it also means 180 # we cannot use set -e since technically the "wait" is failing. 181 wait 182 while (($? > 128)); do 183 wait 184 done 185
