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- #!/bin/bash
- # 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.
- #
- # Saves the gdb index for a given binary and its shared library dependencies.
- #
- # This will run gdb index in parallel on a number of binaries using SIGUSR1
- # as the communication mechanism to simulate a semaphore. Because of the
- # nature of this technique, using "set -e" is very difficult. The SIGUSR1
- # terminates a "wait" with an error which we need to interpret.
- #
- # When modifying this code, most of the real logic is in the index_one_file
- # function. The rest is cleanup + sempahore plumbing.
- function usage_exit {
- echo "Usage: $0 [-f] [-r] [-n] <paths-to-binaries>..."
- echo " -f forces replacement of an existing index."
- echo " -r removes the index section."
- echo " -n don't extract the dependencies of each binary with lld."
- echo " e.g., $0 -n out/Debug/lib.unstripped/lib*"
- echo
- echo " Set TOOLCHAIN_PREFIX to use a non-default set of binutils."
- exit 1
- }
- # Cleanup temp directory and ensure all child jobs are dead-dead.
- function on_exit {
- trap "" EXIT USR1 # Avoid reentrancy.
- local jobs=$(jobs -p)
- if [ -n "$jobs" ]; then
- echo -n "Killing outstanding index jobs..."
- kill -KILL $(jobs -p)
- wait
- echo "done"
- fi
- if [ -d "$directory" ]; then
- echo -n "Removing temp directory $directory..."
- rm -rf "$directory"
- echo done
- fi
- }
- # Add index to one binary.
- function index_one_file {
- local file=$1
- local basename=$(basename "$file")
- local should_index_this_file="${should_index}"
- local readelf_out=$(${TOOLCHAIN_PREFIX}readelf -S "$file")
- if [[ $readelf_out =~ "gdb_index" ]]; then
- if $remove_index; then
- ${TOOLCHAIN_PREFIX}objcopy --remove-section .gdb_index "$file"
- echo "Removed index from $basename."
- else
- echo "Skipped $basename -- already contains index."
- should_index_this_file=false
- fi
- fi
- if $should_index_this_file; then
- local start=$(date +"%s%N")
- echo "Adding index to $basename..."
- ${TOOLCHAIN_PREFIX}gdb -batch "$file" -ex "save gdb-index $directory" \
- -ex "quit"
- local index_file="$directory/$basename.gdb-index"
- if [ -f "$index_file" ]; then
- ${TOOLCHAIN_PREFIX}objcopy --add-section .gdb_index="$index_file" \
- --set-section-flags .gdb_index=readonly "$file" "$file"
- local finish=$(date +"%s%N")
- local elapsed=$(((finish - start) / 1000000))
- echo " ...$basename indexed. [${elapsed}ms]"
- else
- echo " ...$basename unindexable."
- fi
- fi
- }
- # Functions that when combined, concurrently index all files in FILES_TO_INDEX
- # array. The global FILES_TO_INDEX is declared in the main body of the script.
- function async_index {
- # Start a background subshell to run the index command.
- {
- index_one_file $1
- kill -SIGUSR1 $$ # $$ resolves to the parent script.
- exit 129 # See comment above wait loop at bottom.
- } &
- }
- cur_file_num=0
- function index_next {
- if ((cur_file_num >= ${#files_to_index[@]})); then
- return
- fi
- async_index "${files_to_index[cur_file_num]}"
- ((cur_file_num += 1)) || true
- }
- ########
- ### Main body of the script.
- remove_index=false
- should_index=true
- should_index_deps=true
- files_to_index=()
- while (($# > 0)); do
- case "$1" in
- -h)
- usage_exit
- ;;
- -f)
- remove_index=true
- ;;
- -r)
- remove_index=true
- should_index=false
- ;;
- -n)
- should_index_deps=false
- ;;
- -*)
- echo "Invalid option: $1" >&2
- usage_exit
- ;;
- *)
- if [[ ! -f "$1" ]]; then
- echo "Path $1 does not exist."
- exit 1
- fi
- files_to_index+=("$1")
- ;;
- esac
- shift
- done
- if ((${#files_to_index[@]} == 0)); then
- usage_exit
- fi
- dependencies=()
- if $should_index_deps; then
- for file in "${files_to_index[@]}"; do
- # Append the shared library dependencies of this file that
- # have the same dirname. The dirname is a signal that these
- # shared libraries were part of the same build as the binary.
- dependencies+=( \
- $(ldd "$file" 2>/dev/null \
- | grep $(dirname "$file") \
- | sed "s/.*[ \t]\(.*\) (.*/\1/") \
- )
- done
- fi
- files_to_index+=("${dependencies[@]}")
- # Ensure we cleanup on on exit.
- trap on_exit EXIT INT
- # We're good to go! Create temp directory for index files.
- directory=$(mktemp -d)
- echo "Made temp directory $directory."
- # Start concurrent indexing.
- trap index_next USR1
- # 4 is an arbitrary default. When changing, remember we are likely IO bound
- # so basing this off the number of cores is not sensible.
- index_tasks=${INDEX_TASKS:-4}
- for ((i = 0; i < index_tasks; i++)); do
- index_next
- done
- # Do a wait loop. Bash waits that terminate due a trap have an exit
- # code > 128. We also ensure that our subshell's "normal" exit occurs with
- # an exit code > 128. This allows us to do consider a > 128 exit code as
- # an indication that the loop should continue. Unfortunately, it also means
- # we cannot use set -e since technically the "wait" is failing.
- wait
- while (($? > 128)); do
- wait
- done
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