| Message ID | 20190509064635.1445-1-yamada.masahiro@socionext.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | kbuild: add some extra warning flags unconditionally | expand |
On Thu, May 9, 2019 at 8:47 AM Masahiro Yamada <yamada.masahiro@socionext.com> wrote: > > These flags are documented in the GCC 4.6 manual, and recognized by > Clang as well. Let's rip off the cc-option / cc-disable-warning switches. > BTW, is this a speedup when doing CC/LD FLAGS etc checks unconditionally? Asking in general - do you have any numbers :-)? - Sedat - > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> > --- > > scripts/Makefile.extrawarn | 13 +++++++------ > 1 file changed, 7 insertions(+), 6 deletions(-) > > diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn > index 523c4cafe2dc..3ab8d1a303cd 100644 > --- a/scripts/Makefile.extrawarn > +++ b/scripts/Makefile.extrawarn > @@ -23,15 +23,16 @@ warning- := $(empty) > warning-1 := -Wextra -Wunused -Wno-unused-parameter > warning-1 += -Wmissing-declarations > warning-1 += -Wmissing-format-attribute > -warning-1 += $(call cc-option, -Wmissing-prototypes) > +warning-1 += -Wmissing-prototypes > warning-1 += -Wold-style-definition > -warning-1 += $(call cc-option, -Wmissing-include-dirs) > +warning-1 += -Wmissing-include-dirs > warning-1 += $(call cc-option, -Wunused-but-set-variable) > warning-1 += $(call cc-option, -Wunused-const-variable) > warning-1 += $(call cc-option, -Wpacked-not-aligned) > warning-1 += $(call cc-option, -Wstringop-truncation) > -warning-1 += $(call cc-disable-warning, missing-field-initializers) > -warning-1 += $(call cc-disable-warning, sign-compare) > +# The following turn off the warnings enabled by -Wextra > +warning-1 += -Wno-missing-field-initializers > +warning-1 += -Wno-sign-compare > > warning-2 := -Waggregate-return > warning-2 += -Wcast-align > @@ -39,8 +40,8 @@ warning-2 += -Wdisabled-optimization > warning-2 += -Wnested-externs > warning-2 += -Wshadow > warning-2 += $(call cc-option, -Wlogical-op) > -warning-2 += $(call cc-option, -Wmissing-field-initializers) > -warning-2 += $(call cc-option, -Wsign-compare) > +warning-2 += -Wmissing-field-initializers > +warning-2 += -Wsign-compare > warning-2 += $(call cc-option, -Wmaybe-uninitialized) > warning-2 += $(call cc-option, -Wunused-macros) > > -- > 2.17.1 > > -- > You received this message because you are subscribed to the Google Groups "Clang Built Linux" group. > To unsubscribe from this group and stop receiving emails from it, send an email to clang-built-linux+unsubscribe@googlegroups.com. > To post to this group, send email to clang-built-linux@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/20190509064635.1445-1-yamada.masahiro%40socionext.com. > For more options, visit https://groups.google.com/d/optout.
On Thu, May 9, 2019 at 4:11 PM Sedat Dilek <sedat.dilek@gmail.com> wrote: > > On Thu, May 9, 2019 at 8:47 AM Masahiro Yamada > <yamada.masahiro@socionext.com> wrote: > > > > These flags are documented in the GCC 4.6 manual, and recognized by > > Clang as well. Let's rip off the cc-option / cc-disable-warning switches. > > > > BTW, is this a speedup when doing CC/LD FLAGS etc checks unconditionally? Yes. cc-option is somewhat costly because it invoked the compiler to check if the given flag is supported. So, I want to get rid of as many cc-option calls as possible. > Asking in general - do you have any numbers :-)? Removing a couple of cc-options does not make a measurable difference in general use-cases. But, this might be more beneficial for chrome OS because $(CC) is a wrapper and invoking it is much more expensive. > > - Sedat - > > > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> > > --- > > > > scripts/Makefile.extrawarn | 13 +++++++------ > > 1 file changed, 7 insertions(+), 6 deletions(-) > > > > diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn > > index 523c4cafe2dc..3ab8d1a303cd 100644 > > --- a/scripts/Makefile.extrawarn > > +++ b/scripts/Makefile.extrawarn > > @@ -23,15 +23,16 @@ warning- := $(empty) > > warning-1 := -Wextra -Wunused -Wno-unused-parameter > > warning-1 += -Wmissing-declarations > > warning-1 += -Wmissing-format-attribute > > -warning-1 += $(call cc-option, -Wmissing-prototypes) > > +warning-1 += -Wmissing-prototypes > > warning-1 += -Wold-style-definition > > -warning-1 += $(call cc-option, -Wmissing-include-dirs) > > +warning-1 += -Wmissing-include-dirs > > warning-1 += $(call cc-option, -Wunused-but-set-variable) > > warning-1 += $(call cc-option, -Wunused-const-variable) > > warning-1 += $(call cc-option, -Wpacked-not-aligned) > > warning-1 += $(call cc-option, -Wstringop-truncation) > > -warning-1 += $(call cc-disable-warning, missing-field-initializers) > > -warning-1 += $(call cc-disable-warning, sign-compare) > > +# The following turn off the warnings enabled by -Wextra > > +warning-1 += -Wno-missing-field-initializers > > +warning-1 += -Wno-sign-compare > > > > warning-2 := -Waggregate-return > > warning-2 += -Wcast-align > > @@ -39,8 +40,8 @@ warning-2 += -Wdisabled-optimization > > warning-2 += -Wnested-externs > > warning-2 += -Wshadow > > warning-2 += $(call cc-option, -Wlogical-op) > > -warning-2 += $(call cc-option, -Wmissing-field-initializers) > > -warning-2 += $(call cc-option, -Wsign-compare) > > +warning-2 += -Wmissing-field-initializers > > +warning-2 += -Wsign-compare > > warning-2 += $(call cc-option, -Wmaybe-uninitialized) > > warning-2 += $(call cc-option, -Wunused-macros) > > > > -- > > 2.17.1 > > > > -- > > You received this message because you are subscribed to the Google Groups "Clang Built Linux" group. > > To unsubscribe from this group and stop receiving emails from it, send an email to clang-built-linux+unsubscribe@googlegroups.com. > > To post to this group, send email to clang-built-linux@googlegroups.com. > > To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/20190509064635.1445-1-yamada.masahiro%40socionext.com. > > For more options, visit https://groups.google.com/d/optout.
On Thu, May 09, 2019 at 03:46:35PM +0900, Masahiro Yamada wrote: > These flags are documented in the GCC 4.6 manual, and recognized by > Clang as well. Let's rip off the cc-option / cc-disable-warning switches. > > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> > --- > > scripts/Makefile.extrawarn | 13 +++++++------ > 1 file changed, 7 insertions(+), 6 deletions(-) > > diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn > index 523c4cafe2dc..3ab8d1a303cd 100644 > --- a/scripts/Makefile.extrawarn > +++ b/scripts/Makefile.extrawarn > @@ -23,15 +23,16 @@ warning- := $(empty) > warning-1 := -Wextra -Wunused -Wno-unused-parameter > warning-1 += -Wmissing-declarations > warning-1 += -Wmissing-format-attribute > -warning-1 += $(call cc-option, -Wmissing-prototypes) > +warning-1 += -Wmissing-prototypes > warning-1 += -Wold-style-definition > -warning-1 += $(call cc-option, -Wmissing-include-dirs) > +warning-1 += -Wmissing-include-dirs > warning-1 += $(call cc-option, -Wunused-but-set-variable) > warning-1 += $(call cc-option, -Wunused-const-variable) > warning-1 += $(call cc-option, -Wpacked-not-aligned) > warning-1 += $(call cc-option, -Wstringop-truncation) > -warning-1 += $(call cc-disable-warning, missing-field-initializers) > -warning-1 += $(call cc-disable-warning, sign-compare) > +# The following turn off the warnings enabled by -Wextra > +warning-1 += -Wno-missing-field-initializers > +warning-1 += -Wno-sign-compare > > warning-2 := -Waggregate-return > warning-2 += -Wcast-align > @@ -39,8 +40,8 @@ warning-2 += -Wdisabled-optimization > warning-2 += -Wnested-externs > warning-2 += -Wshadow > warning-2 += $(call cc-option, -Wlogical-op) > -warning-2 += $(call cc-option, -Wmissing-field-initializers) > -warning-2 += $(call cc-option, -Wsign-compare) > +warning-2 += -Wmissing-field-initializers > +warning-2 += -Wsign-compare > warning-2 += $(call cc-option, -Wmaybe-uninitialized) > warning-2 += $(call cc-option, -Wunused-macros) > > -- > 2.17.1 >
From: Masahiro Yamada <yamada.masahiro@socionext.com> > On Thu, May 9, 2019 at 4:11 PM Sedat Dilek <sedat.dilek@gmail.com> wrote: > > BTW, is this a speedup when doing CC/LD FLAGS etc checks unconditionally? > > Yes. > cc-option is somewhat costly because it invoked the compiler to > check if the given flag is supported. > > So, I want to get rid of as many cc-option calls as possible. > > > > Asking in general - do you have any numbers :-)? > > Removing a couple of cc-options does not make > a measurable difference in general use-cases. > > But, this might be more beneficial for chrome OS > because $(CC) is a wrapper and invoking it is much more expensive. Android does too, which we plan on removing as we recently measured the performance cost of 5% for having a Python wrapper to aid in bisection. Anyways, I checked these options with clang 4 and gcc 4.6.4 in godbolt. Tested-by: Nick Desaulniers <ndesaulniers@google.com>
On Fri, May 10, 2019 at 1:47 AM Nick Desaulniers <ndesaulniers@google.com> wrote: > > From: Masahiro Yamada <yamada.masahiro@socionext.com> > > On Thu, May 9, 2019 at 4:11 PM Sedat Dilek <sedat.dilek@gmail.com> wrote: > > > BTW, is this a speedup when doing CC/LD FLAGS etc checks unconditionally? > > > > Yes. > > cc-option is somewhat costly because it invoked the compiler to > > check if the given flag is supported. > > > > So, I want to get rid of as many cc-option calls as possible. > > > > > > > Asking in general - do you have any numbers :-)? > > > > Removing a couple of cc-options does not make > > a measurable difference in general use-cases. > > > > But, this might be more beneficial for chrome OS > > because $(CC) is a wrapper and invoking it is much more expensive. > > Android does too, which we plan on removing as we recently measured > the performance cost of 5% for having a Python wrapper to aid in > bisection. > > Anyways, I checked these options with clang 4 and gcc 4.6.4 in godbolt. > Tested-by: Nick Desaulniers <ndesaulniers@google.com> > -- > Thanks, > ~Nick Desaulniers Applied to linux-kbuild.
diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn index 523c4cafe2dc..3ab8d1a303cd 100644 --- a/scripts/Makefile.extrawarn +++ b/scripts/Makefile.extrawarn @@ -23,15 +23,16 @@ warning- := $(empty) warning-1 := -Wextra -Wunused -Wno-unused-parameter warning-1 += -Wmissing-declarations warning-1 += -Wmissing-format-attribute -warning-1 += $(call cc-option, -Wmissing-prototypes) +warning-1 += -Wmissing-prototypes warning-1 += -Wold-style-definition -warning-1 += $(call cc-option, -Wmissing-include-dirs) +warning-1 += -Wmissing-include-dirs warning-1 += $(call cc-option, -Wunused-but-set-variable) warning-1 += $(call cc-option, -Wunused-const-variable) warning-1 += $(call cc-option, -Wpacked-not-aligned) warning-1 += $(call cc-option, -Wstringop-truncation) -warning-1 += $(call cc-disable-warning, missing-field-initializers) -warning-1 += $(call cc-disable-warning, sign-compare) +# The following turn off the warnings enabled by -Wextra +warning-1 += -Wno-missing-field-initializers +warning-1 += -Wno-sign-compare warning-2 := -Waggregate-return warning-2 += -Wcast-align @@ -39,8 +40,8 @@ warning-2 += -Wdisabled-optimization warning-2 += -Wnested-externs warning-2 += -Wshadow warning-2 += $(call cc-option, -Wlogical-op) -warning-2 += $(call cc-option, -Wmissing-field-initializers) -warning-2 += $(call cc-option, -Wsign-compare) +warning-2 += -Wmissing-field-initializers +warning-2 += -Wsign-compare warning-2 += $(call cc-option, -Wmaybe-uninitialized) warning-2 += $(call cc-option, -Wunused-macros)
These flags are documented in the GCC 4.6 manual, and recognized by Clang as well. Let's rip off the cc-option / cc-disable-warning switches. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> --- scripts/Makefile.extrawarn | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-)