From 4d0831e8a029c03f49f434f28b8faef9f0bd403f Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 14 Jun 2020 23:43:41 +0900 Subject: kconfig: unify cc-option and as-option cc-option and as-option are almost the same; both pass the flag to $(CC). The main difference is the cc-option stops before the assemble stage (-S option) whereas as-option stops after (-c option). I chose -S because it is slightly faster, but $(cc-option,-gz=zlib) returns a wrong result (https://lkml.org/lkml/2020/6/9/1529). It has been fixed by commit 7b16994437c7 ("Makefile: Improve compressed debug info support detection"), but the assembler should always be invoked for more reliable compiler option tests. However, you cannot simply replace -S with -c because the following code in lib/Kconfig.debug would break: depends on $(cc-option,-gsplit-dwarf) The combination of -c and -gsplit-dwarf does not accept /dev/null as output. $ cat /dev/null | gcc -gsplit-dwarf -S -x c - -o /dev/null $ echo $? 0 $ cat /dev/null | gcc -gsplit-dwarf -c -x c - -o /dev/null objcopy: Warning: '/dev/null' is not an ordinary file $ echo $? 1 $ cat /dev/null | gcc -gsplit-dwarf -c -x c - -o tmp.o $ echo $? 0 There is another flag that creates an separate file based on the object file path: $ cat /dev/null | gcc -ftest-coverage -c -x c - -o /dev/null :1: error: cannot open /dev/null.gcno So, we cannot use /dev/null to sink the output. Align the cc-option implementation with scripts/Kbuild.include. With -c option used in cc-option, as-option is unneeded. Signed-off-by: Masahiro Yamada Acked-by: Will Deacon --- arch/arm64/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 31380da53689..6eb18f45258e 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1564,7 +1564,7 @@ config CC_HAS_SIGN_RETURN_ADDRESS def_bool $(cc-option,-msign-return-address=all) config AS_HAS_PAC - def_bool $(as-option,-Wa$(comma)-march=armv8.3-a) + def_bool $(cc-option,-Wa$(comma)-march=armv8.3-a) config AS_HAS_CFI_NEGATE_RA_STATE def_bool $(as-instr,.cfi_startproc\n.cfi_negate_ra_state\n.cfi_endproc\n) -- cgit v1.2.3