blob: 992ac16159794685cdf2f233aad43e5883a107e2 [file] [log] [blame]
James Robinson646469d2014-10-03 15:33:28 -07001#!/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.
17function 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.
36function index_one_file {
37 local file=$1
38 local basename=$(basename "$file")
39 local should_index="${SHOULD_INDEX}"
40
James Robinsond753aca2015-01-12 13:07:20 -080041 local readelf_out=$(${TOOLCHAIN_PREFIX}readelf -S "$file")
James Robinson646469d2014-10-03 15:33:28 -070042 if [[ $readelf_out =~ "gdb_index" ]]; then
43 if [ "${REMOVE_INDEX}" = 1 ]; then
James Robinsond753aca2015-01-12 13:07:20 -080044 ${TOOLCHAIN_PREFIX}objcopy --remove-section .gdb_index "$file"
James Robinson646469d2014-10-03 15:33:28 -070045 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 Robinsond753aca2015-01-12 13:07:20 -080056 ${TOOLCHAIN_PREFIX}gdb -batch "$file" -ex "save gdb-index $DIRECTORY" \
57 -ex "quit"
James Robinson646469d2014-10-03 15:33:28 -070058 local index_file="$DIRECTORY/$basename.gdb-index"
59 if [ -f "$index_file" ]; then
James Robinsond753aca2015-01-12 13:07:20 -080060 ${TOOLCHAIN_PREFIX}objcopy --add-section .gdb_index="$index_file" \
James Robinson646469d2014-10-03 15:33:28 -070061 --set-section-flags .gdb_index=readonly "$file" "$file"
62 local finish=$(date +"%s%N")
James Robinsond753aca2015-01-12 13:07:20 -080063 local elapsed=$(((finish - start)/1000000))
64 echo " ...$basename indexed. [${elapsed}ms]"
James Robinson646469d2014-10-03 15:33:28 -070065 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.
73function 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
82CUR_FILE_NUM=0
83function 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
96REMOVE_INDEX=0
97SHOULD_INDEX=1
98while 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
113done
114
115if [[ ! $# == 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
120fi
121
122FILENAME="$1"
123if [[ ! -f "$FILENAME" ]]; then
124 echo "Path $FILENAME does not exist."
125 exit 1
126fi
127
128# Ensure we cleanup on on exit.
129trap on_exit EXIT
130
131# We're good to go! Create temp directory for index files.
132DIRECTORY=$(mktemp -d)
133echo "Made temp directory $DIRECTORY."
134
135# Create array with the filename and all shared libraries that
136# have the same dirname. The dirname is a signal that these
137# shared libraries were part of the same build as the binary.
138declare -a FILES_TO_INDEX=($FILENAME
139 $(ldd "$FILENAME" 2>/dev/null \
140 | grep $(dirname "$FILENAME") \
141 | sed "s/.*[ \t]\(.*\) (.*/\1/")
142)
143
144# Start concurrent indexing.
145trap 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.
149INDEX_TASKS=${INDEX_TASKS:-4}
150for ((i=0;i<${INDEX_TASKS};i++)); do
151 index_next
152done
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.
159wait
160while (( $? > 128 )); do
161 wait
162done