The following commit has been merged into the objtool/core branch of tip: Commit-ID: e36b69e918112430ee53e24238bb87f5146f9acf Gitweb: https://git.kernel.org/tip/e36b69e918112430ee53e24238bb87f5146f9acf Author: Brian Johannesmeyer <bjohannesmeyer@xxxxxxxxx> AuthorDate: Mon, 15 Apr 2024 16:55:36 +02:00 Committer: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> CommitterDate: Tue, 02 Jul 2024 23:38:36 -07:00 scripts/faddr2line: Invoke addr2line as a single long-running process Rather than invoking a separate addr2line process for each address, invoke a single addr2line coprocess, and pass each address to its stdin. Previous work [0] applied a similar change to perf, leading to a ~60x speed-up [1]. If using an object file that is _not_ vmlinux, faddr2line passes a section name argument to addr2line. Because we do not know until runtime which section names will be passed to addr2line, we cannot apply this change to non-vmlinux object files. Hence, it only applies to vmlinux. [0] commit be8ecc57f180 ("perf srcline: Use long-running addr2line per DSO") [1] Link: https://eighty-twenty.org/2021/09/09/perf-addr2line-speed-improvement Signed-off-by: Brian Johannesmeyer <bjohannesmeyer@xxxxxxxxx> Link: https://lore.kernel.org/r/20240415145538.1938745-6-bjohannesmeyer@xxxxxxxxx Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> --- scripts/faddr2line | 52 ++++++++++++++++++++++++++++++++++++++------- 1 file changed, 45 insertions(+), 7 deletions(-) diff --git a/scripts/faddr2line b/scripts/faddr2line index 820680c..48fc8cf 100755 --- a/scripts/faddr2line +++ b/scripts/faddr2line @@ -126,6 +126,48 @@ check_vmlinux() { fi } +init_addr2line() { + local objfile=$1 + + check_vmlinux + + ADDR2LINE_ARGS="--functions --pretty-print --inlines --addresses --exe=$objfile" + if [[ $IS_VMLINUX = 1 ]]; then + # If the executable file is vmlinux, we don't pass section names to + # addr2line, so we can launch it now as a single long-running process. + coproc ADDR2LINE_PROC (${ADDR2LINE} ${ADDR2LINE_ARGS}) + fi +} + +run_addr2line() { + local addr=$1 + local sec_name=$2 + + if [[ $IS_VMLINUX = 1 ]]; then + # We send to the addr2line process: (1) the address, then (2) a sentinel + # value, i.e., something that can't be interpreted as a valid address + # (i.e., ","). This causes addr2line to write out: (1) the answer for + # our address, then (2) either "?? ??:0" or "0x0...0: ..." (if + # using binutils' addr2line), or "," (if using LLVM's addr2line). + echo ${addr} >& "${ADDR2LINE_PROC[1]}" + echo "," >& "${ADDR2LINE_PROC[1]}" + local first_line + read -r first_line <& "${ADDR2LINE_PROC[0]}" + ADDR2LINE_OUT=$(echo "${first_line}" | sed 's/^0x[0-9a-fA-F]*: //') + while read -r line <& "${ADDR2LINE_PROC[0]}"; do + if [[ "$line" == "?? ??:0" ]] || [[ "$line" == "," ]] || [[ $(echo "$line" | ${GREP} "^0x00*: ") ]]; then + break + fi + ADDR2LINE_OUT+=$'\n'$(echo "$line" | sed 's/^0x[0-9a-fA-F]*: //') + done + else + # Run addr2line as a single invocation. + local sec_arg + [[ -z $sec_name ]] && sec_arg="" || sec_arg="--section=${sec_name}" + ADDR2LINE_OUT=$(${ADDR2LINE} ${ADDR2LINE_ARGS} ${sec_arg} ${addr} | sed 's/^0x[0-9a-fA-F]*: //') + fi +} + __faddr2line() { local objfile=$1 local func_addr=$2 @@ -260,12 +302,8 @@ __faddr2line() { # Pass section address to addr2line and strip absolute paths # from the output: - local args="--functions --pretty-print --inlines --addresses --exe=$objfile" - [[ $IS_VMLINUX = 0 ]] && args="$args --section=$sec_name" - local output_with_addr=$(${ADDR2LINE} $args $addr | sed "s; $dir_prefix\(\./\)*; ;") - [[ -z $output_with_addr ]] && continue - - local output=$(echo "${output_with_addr}" | sed 's/^0x[0-9a-fA-F]*: //') + run_addr2line $addr $sec_name + local output=$(echo "${ADDR2LINE_OUT}" | sed "s; $dir_prefix\(\./\)*; ;") [[ -z $output ]] && continue # Default output (non --list): @@ -309,7 +347,7 @@ run_readelf $objfile echo "${ELF_SECHEADERS}" | ${GREP} -q '\.debug_info' || die "CONFIG_DEBUG_INFO not enabled" -check_vmlinux +init_addr2line $objfile DIR_PREFIX=supercalifragilisticexpialidocious find_dir_prefix $objfile