[PATCH v2 2/5] Makefile.compiler: Use KBUILD_AFLAGS for as-option

From: Nick Desaulniers
Date: Wed Aug 31 2022 - 14:44:33 EST


as-instr uses KBUILD_AFLAGS, but as-option uses KBUILD_CFLAGS. This can
cause as-option to fail unexpectedly because clang will emit
-Werror,-Wunused-command-line-argument for various -m and -f flags for
assembler sources.

Callers of as-option (and as-instr) likely want to be adding flags to
KBUILD_AFLAGS/aflags-y, not KBUILD_CFLAGS/cflags-y.

Link: https://github.com/ClangBuiltLinux/linux/issues/1699
Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
---
Changes v1 -> v2:
* Split off changes to arch/x86/boot/compressed/Makefile into parent
patch, as per Masahiro.

scripts/Makefile.compiler | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/scripts/Makefile.compiler b/scripts/Makefile.compiler
index 94d0d40cddb3..d1739f0d3ce3 100644
--- a/scripts/Makefile.compiler
+++ b/scripts/Makefile.compiler
@@ -29,13 +29,13 @@ try-run = $(shell set -e; \
fi)

# as-option
-# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
+# Usage: aflags-y += $(call as-option,-Wa$(comma)-isa=foo,)

as-option = $(call try-run,\
- $(CC) $(KBUILD_CFLAGS) $(1) -c -x assembler /dev/null -o "$$TMP",$(1),$(2))
+ $(CC) $(KBUILD_AFLAGS) $(1) -c -x assembler /dev/null -o "$$TMP",$(1),$(2))

# as-instr
-# Usage: cflags-y += $(call as-instr,instr,option1,option2)
+# Usage: aflags-y += $(call as-instr,instr,option1,option2)

as-instr = $(call try-run,\
printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3))
--
2.37.2.672.g94769d06f0-goog