Unverified Commit 5fa9b82c authored by Anders Roxell's avatar Anders Roxell Committed by Nathan Chancellor
Browse files

scripts: kconfig: merge_config.sh: refactor from shell/sed/grep to awk 



merge_config.sh shell/sed/grep loop scales poorly and is slow.
With Yocto genericarm64 kernel and around 190 config fragments
the script takes more than 20 minutes to run on a fast build machine.
Re-implementation with awk does the same job in 10 seconds.
Using awk since it is likely available in the build environments
and using perl, python etc would introduce more complex runtime
dependencies. awk is good enough and lot better than shell/sed/grep.

Output stays the same but changed execution time means that
parallel job output may be ordered differently.

Signed-off-by: default avatarAnders Roxell <anders.roxell@linaro.org>
Signed-off-by: default avatarMikko Rapeli <mikko.rapeli@linaro.org>
Link: https://patch.msgid.link/20260122105751.2186609-1-mikko.rapeli@linaro.org


Signed-off-by: default avatarNathan Chancellor <nathan@kernel.org>
parent a081b578

scripts/kconfig/merge_config.sh

+128 −40
Original line number Diff line number Diff line
@@ -16,8 +16,8 @@ 
set -e



clean_up() {

	rm -f $TMP_FILE

	rm -f $MERGE_FILE

	rm -f "$TMP_FILE"

	rm -f "$TMP_FILE.new"

}



usage() {
@@ -43,6 +43,10 @@ STRICT=false 
CONFIG_PREFIX=${CONFIG_-CONFIG_}

WARNOVERRIDE=echo



if [ -z "$AWK" ]; then

	AWK=awk

fi



while true; do

	case $1 in

	"-n")
@@ -117,11 +121,8 @@ if [ ! -r "$INITFILE" ]; then 
fi



MERGE_LIST=$*

SED_CONFIG_EXP1="s/^\(${CONFIG_PREFIX}[a-zA-Z0-9_]*\)=.*/\1/p"

SED_CONFIG_EXP2="s/^# \(${CONFIG_PREFIX}[a-zA-Z0-9_]*\) is not set$/\1/p"



TMP_FILE=$(mktemp ./.tmp.config.XXXXXXXXXX)

MERGE_FILE=$(mktemp ./.merge_tmp.config.XXXXXXXXXX)



echo "Using $INITFILE as base"
@@ -136,42 +137,129 @@ for ORIG_MERGE_FILE in $MERGE_LIST ; do 
		echo "The merge file '$ORIG_MERGE_FILE' does not exist.  Exit." >&2

		exit 1

	fi

	cat $ORIG_MERGE_FILE > $MERGE_FILE

	CFG_LIST=$(sed -n -e "$SED_CONFIG_EXP1" -e "$SED_CONFIG_EXP2" $MERGE_FILE)



	for CFG in $CFG_LIST ; do

		grep -q -w $CFG $TMP_FILE || continue

		PREV_VAL=$(grep -w $CFG $TMP_FILE)

		NEW_VAL=$(grep -w $CFG $MERGE_FILE)

		BUILTIN_FLAG=false

		if [ "$BUILTIN" = "true" ] && [ "${NEW_VAL#CONFIG_*=}" = "m" ] && [ "${PREV_VAL#CONFIG_*=}" = "y" ]; then

			${WARNOVERRIDE} Previous  value: $PREV_VAL

			${WARNOVERRIDE} New value:       $NEW_VAL

			${WARNOVERRIDE} -y passed, will not demote y to m

			${WARNOVERRIDE}

			BUILTIN_FLAG=true

		elif [ "x$PREV_VAL" != "x$NEW_VAL" ] ; then

			${WARNOVERRIDE} Value of $CFG is redefined by fragment $ORIG_MERGE_FILE:

			${WARNOVERRIDE} Previous  value: $PREV_VAL

			${WARNOVERRIDE} New value:       $NEW_VAL

			${WARNOVERRIDE}

			if [ "$STRICT" = "true" ]; then

	# Use awk for single-pass processing instead of per-symbol grep/sed

	if ! "$AWK" -v prefix="$CONFIG_PREFIX" \

		-v warnoverride="$WARNOVERRIDE" \

		-v strict="$STRICT" \

		-v builtin="$BUILTIN" \

		-v warnredun="$WARNREDUN" '

	BEGIN {

		strict_violated = 0

		cfg_regex = "^" prefix "[a-zA-Z0-9_]+"

		notset_regex = "^# " prefix "[a-zA-Z0-9_]+ is not set$"

	}



	# Extract config name from a line, returns "" if not a config line

	function get_cfg(line) {

		if (match(line, cfg_regex)) {

			return substr(line, RSTART, RLENGTH)

		} else if (match(line, notset_regex)) {

			# Extract CONFIG_FOO from "# CONFIG_FOO is not set"

			sub(/^# /, "", line)

			sub(/ is not set$/, "", line)

			return line

		}

		return ""

	}



	function warn_builtin(cfg, prev, new) {

		if (warnoverride == "true") return

		print cfg ": -y passed, will not demote y to m"

		print "Previous value: " prev

		print "New value: " new

		print ""

	}



	function warn_redefined(cfg, prev, new) {

		if (warnoverride == "true") return

		print "Value of " cfg " is redefined by fragment " mergefile ":"

		print "Previous value: " prev

		print "New value: " new

		print ""

	}



	function warn_redundant(cfg) {

		if (warnredun != "true" || warnoverride == "true") return

		print "Value of " cfg " is redundant by fragment " mergefile ":"

	}



	# First pass: read merge file, store all lines and index

	FILENAME == ARGV[1] {

	        mergefile = FILENAME

		merge_lines[FNR] = $0

		merge_total = FNR

		cfg = get_cfg($0)

		if (cfg != "") {

			merge_cfg[cfg] = $0

			merge_cfg_line[cfg] = FNR

		}

		next

	}



	# Second pass: process base file (TMP_FILE)

	FILENAME == ARGV[2] {

		cfg = get_cfg($0)



		# Not a config or not in merge file - keep it

		if (cfg == "" || !(cfg in merge_cfg)) {

			print $0 >> ARGV[3]

			next

		}



	        prev_val = $0

		new_val = merge_cfg[cfg]



		# BUILTIN: do not demote y to m

		if (builtin == "true" && new_val ~ /=m$/ && prev_val ~ /=y$/) {

			warn_builtin(cfg, prev_val, new_val)

			print $0 >> ARGV[3]

			skip_merge[merge_cfg_line[cfg]] = 1

			next

		}



		# Values equal - redundant

		if (prev_val == new_val) {

			warn_redundant(cfg)

			next

		}



		# "=n" is the same as "is not set"

		if (prev_val ~ /=n$/ && new_val ~ / is not set$/) {

			print $0 >> ARGV[3]

			next

		}



		# Values differ - redefined

		warn_redefined(cfg, prev_val, new_val)

		if (strict == "true") {

			strict_violated = 1

		}

	}



	# output file, skip all lines

	FILENAME == ARGV[3] {

		nextfile

	}



	END {

		# Newline in case base file lacks trailing newline

		print "" >> ARGV[3]

		# Append merge file, skipping lines marked for builtin preservation

		for (i = 1; i <= merge_total; i++) {

			if (!(i in skip_merge)) {

				print merge_lines[i] >> ARGV[3]

			}

		}

		if (strict_violated) {

			exit 1

		}

	}' \

	"$ORIG_MERGE_FILE" "$TMP_FILE" "$TMP_FILE.new"; then

		# awk exited non-zero, strict mode was violated

		STRICT_MODE_VIOLATED=true

	fi

		elif [ "$WARNREDUN" = "true" ]; then

			${WARNOVERRIDE} Value of $CFG is redundant by fragment $ORIG_MERGE_FILE:

		fi

		if [ "$BUILTIN_FLAG" = "false" ]; then

			sed -i "/$CFG[ =]/d" $TMP_FILE

		else

			sed -i "/$CFG[ =]/d" $MERGE_FILE

		fi

	mv "$TMP_FILE.new" "$TMP_FILE"

done

	# In case the previous file lacks a new line at the end

	echo >> $TMP_FILE

	cat $MERGE_FILE >> $TMP_FILE

done



if [ "$STRICT_MODE_VIOLATED" = "true" ]; then

	echo "The fragment redefined a value and strict mode had been passed."

	exit 1