On 8/16/2021 5:21 PM, 'Nick Desaulniers' via Clang Built Linux wrote:
cc-option-yn can be replaced with cc-option. ie.
Checking for support:
ifeq ($(call cc-option-yn,$(FLAG)),y)
becomes:
ifneq ($(call cc-option,$(FLAG)),)
Checking for lack of support:
ifeq ($(call cc-option-yn,$(FLAG)),n)
becomes:
ifeq ($(call cc-option,$(FLAG)),)
This allows us to remove cc-option-yn. Do so and update the docs with
examples.
Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx>
---
Documentation/kbuild/makefiles.rst | 22 +++++++++-------------
scripts/Makefile.compiler | 5 -----
2 files changed, 9 insertions(+), 18 deletions(-)
diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst
index db3af0b45baf..4538c36d8df0 100644
--- a/Documentation/kbuild/makefiles.rst
+++ b/Documentation/kbuild/makefiles.rst
@@ -650,24 +650,20 @@ more details, with real examples.
-march=pentium-mmx if supported by $(CC), otherwise -march=i586.
The second argument to cc-option is optional, and if omitted,
cflags-y will be assigned no value if first option is not supported.
- Note: cc-option uses KBUILD_CFLAGS for $(CC) options
+ Note: cc-option uses KBUILD_CFLAGS for $(CC) options.
- cc-option-yn
- cc-option-yn is used to check if gcc supports a given option
- and return 'y' if supported, otherwise 'n'.
+ cc-option can be combined with conditionals to perform actions based on tool
+ support.
Example::
- #arch/ppc/Makefile
- biarch := $(call cc-option-yn, -m32)
- aflags-$(biarch) += -a32
- cflags-$(biarch) += -m32
+ ifneq ($(call cc-option,$(FLAG)),)
+ # $(FLAG) is supported
- In the above example, $(biarch) is set to y if $(CC) supports the -m32
- option. When $(biarch) equals 'y', the expanded variables $(aflags-y)
- and $(cflags-y) will be assigned the values -a32 and -m32,
- respectively.
- Note: cc-option-yn uses KBUILD_CFLAGS for $(CC) options
+ Or::
+
+ ifeq ($(call cc-option,$(FLAG)),)
+ # $(FLAG) is not supported
cc-disable-warning
cc-disable-warning checks if gcc supports a given warning and returns
diff --git a/scripts/Makefile.compiler b/scripts/Makefile.compiler
index 86ecd2ac874c..c19c0b544c0f 100644
--- a/scripts/Makefile.compiler
+++ b/scripts/Makefile.compiler
@@ -51,11 +51,6 @@ __cc-option = $(call try-run,\
cc-option = $(call __cc-option, $(CC),\
$(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS),$(1),$(2))
-# cc-option-yn
-# Usage: flag := $(call cc-option-yn,-march=winchip-c6)
-cc-option-yn = $(call try-run,\
- $(CC) -Werror $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",y,n)
-
# cc-disable-warning
# Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable)
cc-disable-warning = $(call try-run,\
