From bbda5ec671d3fe62faefa1cab7270aa586042a4b Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Fri, 30 Nov 2018 10:05:26 +0900 Subject: kbuild: simplify dependency generation for CONFIG_TRIM_UNUSED_KSYMS My main motivation of this commit is to clean up scripts/Kbuild.include and scripts/Makefile.build. Currently, CONFIG_TRIM_UNUSED_KSYMS works with a tricky gimmick; possibly exported symbols are detected by letting $(CPP) replace EXPORT_SYMBOL* with a special string '=== __KSYM_*===', which is post-processed by sed, and passed to fixdep. The extra preprocessing is costly, and hacking cmd_and_fixdep is ugly. I came up with a new way to find exported symbols; insert a dummy symbol __ksym_marker_* to each potentially exported symbol. Those dummy symbols are picked up by $(NM), post-processed by sed, then appended to .*.cmd files. I collected the post-process part to a new shell script scripts/gen_ksymdeps.sh for readability. The dummy symbols are put into the .discard.* section so that the linker script rips them off the final vmlinux or modules. A nice side-effect is building with CONFIG_TRIM_UNUSED_KSYMS will be much faster. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Pitre --- scripts/gen_ksymdeps.sh | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) create mode 100755 scripts/gen_ksymdeps.sh (limited to 'scripts/gen_ksymdeps.sh') diff --git a/scripts/gen_ksymdeps.sh b/scripts/gen_ksymdeps.sh new file mode 100755 index 000000000000..1324986e1362 --- /dev/null +++ b/scripts/gen_ksymdeps.sh @@ -0,0 +1,25 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 + +set -e + +# List of exported symbols +ksyms=$($NM $1 | sed -n 's/.*__ksym_marker_\(.*\)/\1/p' | tr A-Z a-z) + +if [ -z "$ksyms" ]; then + exit 0 +fi + +echo +echo "ksymdeps_$1 := \\" + +for s in $ksyms +do + echo $s | sed -e 's:^_*: $(wildcard include/ksym/:' \ + -e 's:__*:/:g' -e 's/$/.h) \\/' +done + +echo +echo "$1: \$(ksymdeps_$1)" +echo +echo "\$(ksymdeps_$1):" -- cgit