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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 | |
41 local readelf_out=$(${TOOLCHAIN_PREFIX}readelf -S "$file") | |
42 if [[ $readelf_out =~ "gdb_index" ]]; then | |
43 if [ "${REMOVE_INDEX}" = 1 ]; then | |
44 ${TOOLCHAIN_PREFIX}objcopy --remove-section .gdb_index "$file" | |
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 | |
56 ${TOOLCHAIN_PREFIX}gdb -batch "$file" -ex "save gdb-index $DIRECTORY" \ | |
57 -ex "quit" | |
58 local index_file="$DIRECTORY/$basename.gdb-index" | |
59 if [ -f "$index_file" ]; then | |
60 ${TOOLCHAIN_PREFIX}objcopy --add-section .gdb_index="$index_file" \ | |
61 --set-section-flags .gdb_index=readonly "$file" "$file" | |
62 local finish=$(date +"%s%N") | |
63 local elapsed=$(((finish - start)/1000000)) | |
64 echo " ...$basename indexed. [${elapsed}ms]" | |
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 | |
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