On Thu, Sep 1, 2022 at 3:44 AM Nick Desaulniers <ndesaulniers@xxxxxxxxxx> wrote: > > cc-ifversion is GCC specific. Replace it with compiler specific > variants. Update the users of cc-ifversion to use these new macros. > Provide a helper for checking compiler versions for GCC and Clang > simultaneously, that will be used in a follow up patch. > > Cc: Jonathan Corbet <corbet@xxxxxxx> > Cc: linux-doc@xxxxxxxxxxxxxxx > Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx > Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx > Link: https://github.com/ClangBuiltLinux/linux/issues/350 > Link: https://lore.kernel.org/llvm/CAGG=3QWSAUakO42kubrCap8fp-gm1ERJJAYXTnP1iHk_wrH=BQ@xxxxxxxxxxxxxx/ > Suggested-by: Bill Wendling <morbo@xxxxxxxxxx> > Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> > --- > Changes v1 -> v2: > * New patch. > > Documentation/kbuild/makefiles.rst | 44 +++++++++++++++------ > Makefile | 4 +- > drivers/gpu/drm/amd/display/dc/dml/Makefile | 12 ++---- > scripts/Makefile.compiler | 15 +++++-- > 4 files changed, 49 insertions(+), 26 deletions(-) > > diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst > index 11a296e52d68..e46f5b45c422 100644 > --- a/Documentation/kbuild/makefiles.rst > +++ b/Documentation/kbuild/makefiles.rst > @@ -682,22 +682,42 @@ 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-min-version > + cc-min-version tests if the value of $(CONFIG_GCC_VERSION) is greater > + than or equal to the first value provided, or if the value of > + $(CONFIG_CLANG_VERSION) is greater than or equal to the second value > + provided, and evaluates > + to y if so. > + > + Example:: > + > + cflags-$(call cc-min-version, 70100, 110000) := -foo > + > + In this example, cflags-y will be assigned the value -foo if $(CC) is gcc and > + $(CONFIG_GCC_VERSION) is >= 7.1, or 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 $(CC) in path with > diff --git a/Makefile b/Makefile > index 952d354069a4..caa39ecb1136 100644 > --- a/Makefile > +++ b/Makefile > @@ -972,7 +972,7 @@ ifdef CONFIG_CC_IS_GCC > KBUILD_CFLAGS += -Wno-maybe-uninitialized > endif > > -ifdef CONFIG_CC_IS_GCC > +ifeq ($(call gcc-min-version, 90100),y) > # 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 > @@ -984,7 +984,7 @@ 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@xxxxxxxxxxxxxxxx > -KBUILD_CFLAGS += $(call cc-ifversion, -ge, 0901, -Wno-alloc-size-larger-than) > +KBUILD_CFLAGS += -Wno-alloc-size-larger-than > endif > > # disable invalid "can't wrap" optimizations for signed / pointers > diff --git a/drivers/gpu/drm/amd/display/dc/dml/Makefile b/drivers/gpu/drm/amd/display/dc/dml/Makefile > index 86a3b5bfd699..d8ee4743b2e3 100644 > --- a/drivers/gpu/drm/amd/display/dc/dml/Makefile > +++ b/drivers/gpu/drm/amd/display/dc/dml/Makefile > @@ -33,20 +33,14 @@ ifdef CONFIG_PPC64 > dml_ccflags := -mhard-float -maltivec > endif > > -ifdef CONFIG_CC_IS_GCC > -ifeq ($(call cc-ifversion, -lt, 0701, y), y) > -IS_OLD_GCC = 1 > -endif > -endif > - > ifdef CONFIG_X86 > -ifdef IS_OLD_GCC > +ifeq ($(call gcc-min-version, 70100),y) > +dml_ccflags += -msse2 > +else > # Stack alignment mismatch, proceed with caution. > # GCC < 7.1 cannot compile code using `double` and -mpreferred-stack-boundary=3 > # (8B stack alignment). > dml_ccflags += -mpreferred-stack-boundary=4 > -else > -dml_ccflags += -msse2 > endif > endif > > diff --git a/scripts/Makefile.compiler b/scripts/Makefile.compiler > index d1739f0d3ce3..13dade724fa3 100644 > --- a/scripts/Makefile.compiler > +++ b/scripts/Makefile.compiler > @@ -61,9 +61,18 @@ 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) -ge $(1) ] && echo y) > + > +# clang-min-version > +# Usage: cflags-$(call clang-min-version, 110000) += -foo > +clang-min-version = $(shell [ $(CONFIG_CLANG_VERSION) -ge $(1) ] && echo y) > + > +# cc-min-version > +# Usage: cflags-$(call cc-min-version, 701000, 110000) > +# ^ GCC ^ Clang > +cc-min-version = $(filter y, $(call gcc-min-version, $(1)), $(call clang-min-version, $(2))) A more intuitive and more efficient form would be: cc-min-version = $(or $(call gcc-min-version, $(1)), $(call clang-min-version, $(2))) In your implementation, both gcc-min-version and clang-min-version are expanded before being passed to $(filter ...). So the shell is always invoked twice. $(or A, B) is lazily expanded; A is evaluated first. If and only if A is empty, B is expanded. If gcc-min-version is met, the shell invocation in clang-min-version will be short-cut. But, I do not find a place where cc-min-version is useful. Looking at the next patch, # gcc-11+, clang-14+ ifeq ($(call cc-min-version, 110000, 140000),y) dwarf-version-y := 5 else dwarf-version-y := 4 endif ... can be written in a more simpler way: dwarf-version-y := 4 dwarf-version-$(call gcc-min-version, 110000) := 5 dwarf-version-$(call clang-min-version, 140000) := 5 With $(call cc-min-version, 110000, 140000), you never know the meaning of 110000, 140000 until you see the definition of this macro. So, you feel like adding the comment "gcc-11+, clang-14+". The latter form, the code is self-documenting. > # ld-option > # Usage: KBUILD_LDFLAGS += $(call ld-option, -X, -Y) > -- > 2.37.2.672.g94769d06f0-goog > -- Best Regards Masahiro Yamada
