Commit 88b61e3b authored by Nick Desaulniers's avatar Nick Desaulniers Committed by Masahiro Yamada
Browse files

Makefile.compiler: replace cc-ifversion with compiler-specific macros 

cc-ifversion is GCC specific. Replace it with compiler specific
variants. Update the users of cc-ifversion to use these new macros.

Link: https://github.com/ClangBuiltLinux/linux/issues/350
Link: https://lore.kernel.org/llvm/CAGG=3QWSAUakO42kubrCap8fp-gm1ERJJAYXTnP1iHk_wrH=BQ@mail.gmail.com/


Suggested-by: default avatarBill Wendling <morbo@google.com>
Reviewed-by: default avatarNathan Chancellor <nathan@kernel.org>
Signed-off-by: default avatarNick Desaulniers <ndesaulniers@google.com>
Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
parent 2e07005f

Documentation/kbuild/makefiles.rst

+17 −12
Original line number Diff line number Diff line
@@ -682,22 +682,27 @@ more details, with real examples. 
	In the above example, -Wno-unused-but-set-variable will be added to

	KBUILD_CFLAGS only if gcc really accepts it.



    cc-ifversion

	cc-ifversion tests the version of $(CC) and equals the fourth parameter

	if version expression is true, or the fifth (if given) if the version

	expression is false.

    gcc-min-version

	gcc-min-version tests if the value of $(CONFIG_GCC_VERSION) is greater than

	or equal to the provided value and evaluates to y if so.



	Example::



		#fs/reiserfs/Makefile

		ccflags-y := $(call cc-ifversion, -lt, 0402, -O1)

		cflags-$(call gcc-min-version, 70100) := -foo



	In this example, ccflags-y will be assigned the value -O1 if the

	$(CC) version is less than 4.2.

	cc-ifversion takes all the shell operators:

	-eq, -ne, -lt, -le, -gt, and -ge

	The third parameter may be a text as in this example, but it may also

	be an expanded variable or a macro.

	In this example, cflags-y will be assigned the value -foo if $(CC) is gcc and

	$(CONFIG_GCC_VERSION) is >= 7.1.



    clang-min-version

	clang-min-version tests if the value of $(CONFIG_CLANG_VERSION) is greater

	than or equal to the provided value and evaluates to y if so.



	Example::



		cflags-$(call clang-min-version, 110000) := -foo



	In this example, cflags-y will be assigned the value -foo if $(CC) is clang

	and $(CONFIG_CLANG_VERSION) is >= 11.0.0.



    cc-cross-prefix

	cc-cross-prefix is used to check if there exists a $(CC) in path with

Makefile

+2 −4
Original line number Diff line number Diff line
@@ -790,7 +790,6 @@ KBUILD_CFLAGS += $(stackp-flags-y) 


KBUILD_CFLAGS-$(CONFIG_WERROR) += -Werror

KBUILD_CFLAGS-$(CONFIG_CC_NO_ARRAY_BOUNDS) += -Wno-array-bounds

KBUILD_CFLAGS += $(KBUILD_CFLAGS-y) $(CONFIG_CC_IMPLICIT_FALLTHROUGH)



ifdef CONFIG_CC_IS_CLANG

KBUILD_CPPFLAGS += -Qunused-arguments
@@ -972,7 +971,6 @@ ifdef CONFIG_CC_IS_GCC 
KBUILD_CFLAGS += -Wno-maybe-uninitialized

endif



ifdef CONFIG_CC_IS_GCC

# The allocators already balk at large sizes, so silence the compiler

# warnings for bounds checks involving those possible values. While

# -Wno-alloc-size-larger-than would normally be used here, earlier versions
@@ -984,8 +982,8 @@ ifdef CONFIG_CC_IS_GCC 
# ignored, continuing to default to PTRDIFF_MAX. So, left with no other

# choice, we must perform a versioned check to disable this warning.

# https://lore.kernel.org/lkml/20210824115859.187f272f@canb.auug.org.au

KBUILD_CFLAGS += $(call cc-ifversion, -ge, 0901, -Wno-alloc-size-larger-than)

endif

KBUILD_CFLAGS-$(call gcc-min-version, 90100) += -Wno-alloc-size-larger-than

KBUILD_CFLAGS += $(KBUILD_CFLAGS-y) $(CONFIG_CC_IMPLICIT_FALLTHROUGH)



# disable invalid "can't wrap" optimizations for signed / pointers

KBUILD_CFLAGS	+= -fno-strict-overflow

drivers/gpu/drm/amd/display/dc/dml/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -34,7 +34,7 @@ dml_ccflags := -mhard-float -maltivec 
endif



ifdef CONFIG_CC_IS_GCC

ifeq ($(call cc-ifversion, -lt, 0701, y), y)

ifneq ($(call gcc-min-version, 70100),y)

IS_OLD_GCC = 1

endif

endif

scripts/Makefile.compiler

+7 −3
Original line number Diff line number Diff line
@@ -61,9 +61,13 @@ cc-option-yn = $(call try-run,\ 
cc-disable-warning = $(call try-run,\

	$(CC) -Werror $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))



# cc-ifversion

# Usage:  EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)

cc-ifversion = $(shell [ $(CONFIG_GCC_VERSION)0 $(1) $(2)000 ] && echo $(3) || echo $(4))

# gcc-min-version

# Usage: cflags-$(call gcc-min-version, 70100) += -foo

gcc-min-version = $(shell [ $(CONFIG_GCC_VERSION)0 -ge $(1)0 ] && echo y)



# clang-min-version

# Usage: cflags-$(call clang-min-version, 110000) += -foo

clang-min-version = $(shell [ $(CONFIG_CLANG_VERSION)0 -ge $(1)0 ] && echo y)



# ld-option

# Usage: KBUILD_LDFLAGS += $(call ld-option, -X, -Y)

scripts/Makefile.extrawarn

+2 −2
Original line number Diff line number Diff line
@@ -48,7 +48,7 @@ else 
ifdef CONFIG_CC_IS_CLANG

KBUILD_CFLAGS += -Wno-initializer-overrides

# Clang before clang-16 would warn on default argument promotions.

ifeq ($(shell [ $(CONFIG_CLANG_VERSION) -lt 160000 ] && echo y),y)

ifneq ($(call clang-min-version, 160000),y)

# Disable -Wformat

KBUILD_CFLAGS += -Wno-format

# Then re-enable flags that were part of the -Wformat group that aren't
@@ -56,7 +56,7 @@ KBUILD_CFLAGS += -Wno-format 
KBUILD_CFLAGS += -Wformat-extra-args -Wformat-invalid-specifier

KBUILD_CFLAGS += -Wformat-zero-length -Wnonnull

# Requires clang-12+.

ifeq ($(shell [ $(CONFIG_CLANG_VERSION) -ge 120000 ] && echo y),y)

ifeq ($(call clang-min-version, 120000),y)

KBUILD_CFLAGS += -Wformat-insufficient-args

endif

endif