25 Nov, 2020
1 commit
-
This warning behaves differently depending on the architecture
and compiler. Using x86 gcc, we get no output at all because
gcc knows the architecture can handle unaligned accesses.Using x86 clang, or gcc on an architecture that needs to
manually deal with unaligned accesses, the build log is
completely flooded with these warnings, as they are commonly
invoked by inline functions of networking headers, e.g.include/linux/skbuff.h:1426:26: warning: cast increases required alignment of target type [-Wcast-align]
The compiler is correct to point this out, as we are dealing
with undefined behavior that does cause problems in practice,
but there is also no good way to rewrite the code in commonly
included headers to a safer method.Signed-off-by: Arnd Bergmann
Reviewed-by: Nathan Chancellor
Signed-off-by: Masahiro Yamada
18 Aug, 2020
1 commit
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This -Wsign-compare compiler warning can be very noisy
and most of the suggested conversions are unnecessary.Make the warning W=3 so it's described under the
"can most likely be ignored" block.Signed-off-by: Joe Perches
Signed-off-by: Masahiro Yamada
10 Jul, 2020
1 commit
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-Wtype-limits is included in -Wextra which is added at W=1. It warns
(among other things) that 'comparison of an unsigned variable `< 0` is
always false. This causes noisy warnings, especially when used in
macros, hence it is more suitable for W=2.Link: https://lore.kernel.org/lkml/CAHk-=wiKCXEWKJ9dWUimGbrVRo_N2RosESUw8E7m9AEtyZcu=w@mail.gmail.com/
Signed-off-by: Rikard Falkeborn
Suggested-by: Arnd Bergmann
Acked-by: Andy Shevchenko
Signed-off-by: Linus Torvalds
08 Apr, 2020
1 commit
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Currently, we disable -Wtautological-compare, which in turn disables a
bunch of more specific tautological comparison warnings that are useful
for the kernel such as -Wtautological-bitwise-compare. See clang's
documentation below for the other warnings that are suppressed by
-Wtautological-compare. Now that all of the major/noisy warnings have
been fixed, enable -Wtautological-compare so that more issues can be
caught at build time by various continuous integration setups.-Wtautological-constant-out-of-range-compare is kept disabled under a
normal build but visible at W=1 because there are places in the kernel
where a constant or variable size can change based on the kernel
configuration. These are not fixed in a clean/concise way and the ones
I have audited so far appear to be harmless. It is not a subgroup but
rather just one warning so we do not lose out on much coverage by
default.Link: https://github.com/ClangBuiltLinux/linux/issues/488
Link: http://releases.llvm.org/10.0.0/tools/clang/docs/DiagnosticsReference.html#wtautological-compare
Link: https://bugs.llvm.org/show_bug.cgi?id=42666
Signed-off-by: Nathan Chancellor
Signed-off-by: Masahiro Yamada
14 Mar, 2020
1 commit
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Clang's -Wpointer-to-int-cast deviates from GCC in that it warns when
casting to enums. The kernel does this in certain places, such as device
tree matches to set the version of the device being used, which allows
the kernel to avoid using a gigantic union.https://elixir.bootlin.com/linux/v5.5.8/source/drivers/ata/ahci_brcm.c#L428
https://elixir.bootlin.com/linux/v5.5.8/source/drivers/ata/ahci_brcm.c#L402
https://elixir.bootlin.com/linux/v5.5.8/source/include/linux/mod_devicetable.h#L264To avoid a ton of false positive warnings, disable this particular part
of the warning, which has been split off into a separate diagnostic so
that the entire warning does not need to be turned off for clang. It
will be visible under W=1 in case people want to go about fixing these
easily and enabling the warning treewide.Cc: stable@vger.kernel.org
Link: https://github.com/ClangBuiltLinux/linux/issues/887
Link: https://github.com/llvm/llvm-project/commit/2a41b31fcdfcb67ab7038fc2ffb606fd50b83a84
Signed-off-by: Nathan Chancellor
Signed-off-by: Masahiro Yamada
09 Sep, 2019
1 commit
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GCC and Clang have different policy for -Wunused-function; GCC does not
warn unused static inline functions at all whereas Clang does if they
are defined in source files instead of included headers although it has
been suppressed since commit abb2ea7dfd82 ("compiler, clang: suppress
warning for unused static inline functions").We often miss to delete unused functions where 'static inline' is used
in *.c files since there is no tool to detect them. Unused code remains
until somebody notices. For example, commit 075ddd75680f ("regulator:
core: remove unused rdev_get_supply()").Let's remove __maybe_unused from the inline macro to allow Clang to
start finding unused static inline functions. For now, we do this only
for W=1 build since it is not a good idea to sprinkle warnings for the
normal build (e.g. 35 warnings for arch/x86/configs/x86_64_defconfig).My initial attempt was to add -Wno-unused-function for no W= build
(https://lore.kernel.org/patchwork/patch/1120594/)Nathan Chancellor pointed out that would weaken Clang's checks since
we would no longer get -Wunused-function without W=1. It is true GCC
would catch unused static non-inline functions, but it would weaken
Clang as a standalone compiler, at least.Hence, here is a counter implementation. The current problem is, W=...
only controls compiler flags, which are globally effective. There is
no way to address only 'static inline' functions.This commit defines KBUILD_EXTRA_WARN[123] corresponding to W=[123].
When KBUILD_EXTRA_WARN1 is defined, __maybe_unused is omitted from
the 'inline' macro.The new macro __inline_maybe_unused makes the code a bit uglier, so I
hope we can remove it entirely after fixing most of the warnings.If you contribute to code clean-up, please run "make CC=clang W=1"
and check -Wunused-function warnings. You will find lots of unused
functions.Some of them are false-positives because the call-sites are disabled
by #ifdef. I do not like to abuse the inline keyword for suppressing
unused-function warnings because it is intended to be a hint for the
compiler optimization. I prefer #ifdef around the definition, or
__maybe_unused if #ifdef would make the code too ugly.Signed-off-by: Masahiro Yamada
Reviewed-by: Nathan Chancellor
Tested-by: Nathan Chancellor
06 Sep, 2019
2 commits
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KBUILD_ENABLE_EXTRA_GCC_CHECKS started as a switch to add extra warning
options for GCC, but now it is a historical misnomer since we use it
also for Clang, DTC, and even kernel-doc.Rename it to more sensible, shorter KBUILD_EXTRA_WARN.
For the backward compatibility, KBUILD_ENABLE_EXTRA_GCC_CHECKS is still
supported (but not advertised in the documentation).I also fixed up 'make help', and updated the documentation.
Signed-off-by: Masahiro Yamada
Reviewed-by: Nathan Chancellor
Reviewed-by: Nick Desaulniers
Reviewed-by: Sedat Dilek -
Instead of the warning-[123] magic, let's accumulate compiler options
to KBUILD_CFLAGS directly as the top Makefile does. I think this makes
it easier to understand what is going on in this file.This commit slightly changes the behavior, I think all of which are OK.
[1] Currently, cc-option calls are needlessly evaluated. For example,
warning-3 += $(call cc-option, -Wpacked-bitfield-compat)
needs evaluating only when W=3, but it is actually evaluated for
W=1, W=2 as well. With this commit, only relevant cc-option calls
will be evaluated. This is a slight optimization.[2] Currently, unsupported level like W=4 is checked by:
$(error W=$(KBUILD_ENABLE_EXTRA_GCC_CHECKS) is unknown)
This will no longer be checked, but I do not think it is a big
deal.[3] Currently, 4 Clang warnings (Winitializer-overrides, Wformat,
Wsign-compare, Wformat-zero-length) are shown by any of W=1, W=2,
and W=3. With this commit, they will be warned only by W=1. I
think this is a more correct behavior since each warning belongs
to only one group.For understanding this commit correctly:
We have 3 warning groups, W=1, W=2, and W=3. You may think W=3 has a
higher level than W=1, but they are actually independent. If you like,
you can combine them like W=13. To enable all the warnings, you can
pass W=123. It is shown by 'make help', but not noticed much. Since we
support W= combination, there should not exist intersection among the
three groups. If we enable Winitializer-overrides for W=1, we do not
need to for W=2 or W=3. This is the reason why I think the change [3]
makes sense.The documentation says -Winitializer-overrides is enabled by default.
(https://clang.llvm.org/docs/DiagnosticsReference.html#winitializer-overrides)
We negate it by passing -Wno-initializer-overrides for the normal
build, but we do not do that for W=1. This means, W=1 effectively
enables -Winitializer-overrides by the clang's default. The same for
the other three.Add comments in case people are confused with the code.
Signed-off-by: Masahiro Yamada
Reviewed-by: Nathan Chancellor
Tested-by: Sedat Dilek
Acked-by: Nick Desaulniers
Acked-by: Miguel Ojeda
24 Jun, 2019
2 commits
-
This flag turns off several other warnings that would
be useful. Most notably -warn_unused_result is disabled.
All of the following warnings are currently disabled:UnusedValue
|-UnusedComparison
|-warn_unused_comparison
|-UnusedResult
|-warn_unused_result
|-UnevaluatedExpression
|-PotentiallyEvaluatedExpression
|-warn_side_effects_typeid
|-warn_side_effects_unevaluated_context
|-warn_unused_expr
|-warn_unused_voidptr
|-warn_unused_container_subscript_expr
|-warn_unused_callWith this flag removed there are ~10 warnings.
Patches have been submitted for each of these warnings.Reported-by: Nick Desaulniers
Cc: clang-built-linux@googlegroups.com
Link: https://github.com/ClangBuiltLinux/linux/issues/520
Signed-off-by: Nathan Huckleberry
Reviewed-by: Nick Desaulniers
Signed-off-by: Masahiro Yamada -
This helps fine very dodgy behavior through both -Wuninitialized
(warning that a variable is always uninitialized) and
-Wsometimes-uninitialized (warning that a variable is sometimes
uninitialized, like GCC's -Wmaybe-uninitialized). These warnings
catch things that GCC doesn't such as:https://lore.kernel.org/lkml/86649ee4-9794-77a3-502c-f4cd10019c36@lca.pw/
We very much want to catch these so turn this warning on so that CI is
aware of it.Link: https://github.com/ClangBuiltLinux/linux/issues/381
Signed-off-by: Nathan Chancellor
Reviewed-by: Nick Desaulniers
Signed-off-by: Masahiro Yamada
09 Jun, 2019
1 commit
-
It makes little sense to pass -Waggregate-return these days since large
part of the linux kernel rely on returning struct(s). For instance:../include/linux/timekeeping.h: In function 'show_uptime':
../include/linux/ktime.h:91:34: error: function call has aggregate value [-Werror=aggregate-return]
#define ktime_to_timespec64(kt) ns_to_timespec64((kt))
^~~~~~~~~~~~~~~~~~~~~~
../include/linux/timekeeping.h:166:8: note: in expansion of macro 'ktime_to_timespec64'
*ts = ktime_to_timespec64(ktime_get_coarse_boottime());Remove this warning from W=2 completely.
Signed-off-by: Mathieu Malaterre
Signed-off-by: Masahiro Yamada
18 May, 2019
2 commits
-
We do not support old Clang versions. Upgrade your clang version
if any of these flags is unsupported.Let's add all flags inside ifdef CONFIG_CC_IS_CLANG unconditionally.
Signed-off-by: Masahiro Yamada
Reviewed-by: Sedat Dilek
Reviewed-by: Nathan Chancellor
Tested-by: Nick Desaulniers -
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
Reviewed-by: Nathan Chancellor
Tested-by: Nick Desaulniers
04 Nov, 2018
1 commit
-
Pull Kbuild updates from Masahiro Yamada:
- clean-up leftovers in Kconfig files
- remove stale oldnoconfig and silentoldconfig targets
- remove unneeded cc-fullversion and cc-name variables
- improve merge_config script to allow overriding option prefix
* tag 'kbuild-v4.20-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kbuild: remove cc-name variable
kbuild: replace cc-name test with CONFIG_CC_IS_CLANG
merge_config.sh: Allow to define config prefix
kbuild: remove unused cc-fullversion variable
kconfig: remove silentoldconfig target
kconfig: remove oldnoconfig target
powerpc: PCI_MSI needs PCI
powerpc: remove CONFIG_MCA leftovers
powerpc: remove CONFIG_PCI_QSPAN
scsi: aha152x: rename the PCMCIA define
02 Nov, 2018
2 commits
-
Evaluating cc-name invokes the compiler every time even when you are
not compiling anything, like 'make help'. This is not efficient.The compiler type has been already detected in the Kconfig stage.
Use CONFIG_CC_IS_CLANG, instead.Signed-off-by: Masahiro Yamada
Acked-by: Michael Ellerman (powerpc)
Acked-by: Paul Burton (MIPS)
Acked-by: Joel Stanley -
Pull compiler attribute updates from Miguel Ojeda:
"This is an effort to disentangle the include/linux/compiler*.h headers
and bring them up to date.The main idea behind the series is to use feature checking macros
(i.e. __has_attribute) instead of compiler version checks (e.g.
GCC_VERSION), which are compiler-agnostic (so they can be shared,
reducing the size of compiler-specific headers) and version-agnostic.Other related improvements have been performed in the headers as well,
which on top of the use of __has_attribute it has amounted to a
significant simplification of these headers (e.g. GCC_VERSION is now
only guarding a few non-attribute macros).This series should also help the efforts to support compiling the
kernel with clang and icc. A fair amount of documentation and comments
have also been added, clarified or removed; and the headers are now
more readable, which should help kernel developers in general.The series was triggered due to the move to gcc >= 4.6. In turn, this
series has also triggered Sparse to gain the ability to recognize
__has_attribute on its own.Finally, the __nonstring variable attribute series has been also
applied on top; plus two related patches from Nick Desaulniers for
unreachable() that came a bit afterwards"* tag 'compiler-attributes-for-linus-4.20-rc1' of https://github.com/ojeda/linux:
compiler-gcc: remove comment about gcc 4.5 from unreachable()
compiler.h: update definition of unreachable()
Compiler Attributes: ext4: remove local __nonstring definition
Compiler Attributes: auxdisplay: panel: use __nonstring
Compiler Attributes: enable -Wstringop-truncation on W=1 (gcc >= 8)
Compiler Attributes: add support for __nonstring (gcc >= 8)
Compiler Attributes: add MAINTAINERS entry
Compiler Attributes: add Doc/process/programming-language.rst
Compiler Attributes: remove uses of __attribute__ from compiler.h
Compiler Attributes: KENTRY used twice the "used" attribute
Compiler Attributes: use feature checks instead of version checks
Compiler Attributes: add missing SPDX ID in compiler_types.h
Compiler Attributes: remove unneeded sparse (__CHECKER__) tests
Compiler Attributes: homogenize __must_be_array
Compiler Attributes: remove unneeded tests
Compiler Attributes: always use the extra-underscores syntax
Compiler Attributes: remove unused attributes
11 Oct, 2018
1 commit
-
Now that Variable Length Arrays (VLAs) have been entirely removed[1]
from the kernel, enable the VLA warning globally. The only exceptions
to this are the KASan an UBSan tests which are explicitly checking that
VLAs trigger their respective tests.[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com
Cc: Masahiro Yamada
Cc: Andrew Morton
Cc: David Airlie
Cc: linux-kbuild@vger.kernel.org
Cc: intel-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Kees Cook
01 Oct, 2018
1 commit
-
Commit 217c3e019675 ("disable stringop truncation warnings for now")
disabled -Wstringop-truncation since it was too noisy.Having __nonstring available allows us to let GCC know that a string
is not meant to be NUL-terminated, which helps suppressing some
-Wstringop-truncation warnings.Note that using __nonstring actually triggers other warnings
(-Wstringop-overflow, which is on by default) which may be real
problems. Therefore, cleaning up -Wstringop-truncation warnings
also buys us the ability to uncover further potential problems.To encourage the use of __nonstring, we put the warning back at W=1.
In the future, if we end up with a fairly warning-free tree,
we might want to enable it by default.Tested-by: Sedat Dilek # on top of v4.19-rc5, clang 7
Reviewed-by: Kees Cook
Reviewed-by: Nick Desaulniers
Reviewed-by: Luc Van Oostenryck
Signed-off-by: Miguel Ojeda
18 Jan, 2018
1 commit
-
gcc-8 reports many -Wpacked-not-aligned warnings. The below are some
examples../include/linux/ceph/msgr.h:67:1: warning: alignment 1 of 'struct
ceph_entity_addr' is less than 8 [-Wpacked-not-aligned]
} __attribute__ ((packed));./include/linux/ceph/msgr.h:67:1: warning: alignment 1 of 'struct
ceph_entity_addr' is less than 8 [-Wpacked-not-aligned]
} __attribute__ ((packed));./include/linux/ceph/msgr.h:67:1: warning: alignment 1 of 'struct
ceph_entity_addr' is less than 8 [-Wpacked-not-aligned]
} __attribute__ ((packed));This patch suppresses this kind of warnings for default setting.
Signed-off-by: Xiongfeng Wang
Signed-off-by: Masahiro Yamada
02 Nov, 2017
1 commit
-
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.By default all files without license information are under the default
license of the kernel, which is GPL version 2.Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if
Reviewed-by: Philippe Ombredanne
Reviewed-by: Thomas Gleixner
Signed-off-by: Greg Kroah-Hartman
01 Sep, 2017
1 commit
-
We have lots of dead defines and macros in drivers, lets offer users a way
to detect and eventually remove them.Signed-off-by: Johannes Thumshirn
Signed-off-by: Masahiro Yamada
23 Apr, 2017
1 commit
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Since commit c3f0d0bc5b01 ("kbuild, LLVMLinux: Add -Werror to
cc-option to support clang"), cc-option and friends work nicely
for clang.However, -Wno-unknown-warning-option makes clang happy with any
unknown warning options even if -Werror is specified.Once -Wno-unknown-warning-option is added, any succeeding call of
cc-disable-warning is evaluated positive, then unknown warning
options are accepted. This should be dropped.Signed-off-by: Masahiro Yamada
12 Nov, 2016
2 commits
-
Previously the warnings were added back at the W=1 level and above, this
now turns them on again by default, assuming that we have addressed all
warnings and again have a clean build for v4.10.I found a number of new warnings in linux-next already and submitted
bugfixes for those. Hopefully they are caught by the 0day builder in
the future as soon as this patch is merged.Signed-off-by: Arnd Bergmann
Signed-off-by: Linus Torvalds -
Traditionally, we have always had warnings about uninitialized variables
enabled, as this is part of -Wall, and generally a good idea [1], but it
also always produced false positives, mainly because this is a variation
of the halting problem and provably impossible to get right in all cases
[2].Various people have identified cases that are particularly bad for false
positives, and in commit e74fc973b6e5 ("Turn off -Wmaybe-uninitialized
when building with -Os"), I turned off the warning for any build that
was done with CC_OPTIMIZE_FOR_SIZE. This drastically reduced the number
of false positive warnings in the default build but unfortunately had
the side effect of turning the warning off completely in 'allmodconfig'
builds, which in turn led to a lot of warnings (both actual bugs, and
remaining false positives) to go in unnoticed.With commit 877417e6ffb9 ("Kbuild: change CC_OPTIMIZE_FOR_SIZE
definition") enabled the warning again for allmodconfig builds in v4.7
and in v4.8-rc1, I had finally managed to address all warnings I get in
an ARM allmodconfig build and most other maybe-uninitialized warnings
for ARM randconfig builds.However, commit 6e8d666e9253 ("Disable "maybe-uninitialized" warning
globally") was merged at the same time and disabled it completely for
all configurations, because of false-positive warnings on x86 that I had
not addressed until then. This caused a lot of actual bugs to get
merged into mainline, and I sent several dozen patches for these during
the v4.9 development cycle. Most of these are actual bugs, some are for
correct code that is safe because it is only called under external
constraints that make it impossible to run into the case that gcc sees,
and in a few cases gcc is just stupid and finds something that can
obviously never happen.I have now done a few thousand randconfig builds on x86 and collected
all patches that I needed to address every single warning I got (I can
provide the combined patch for the other warnings if anyone is
interested), so I hope we can get the warning back and let people catch
the actual bugs earlier.This reverts the change to disable the warning completely and for now
brings it back at the "make W=1" level, so we can get it merged into
mainline without introducing false positives. A follow-up patch enables
it on all levels unless some configuration option turns it off because
of false-positives.Link: https://rusty.ozlabs.org/?p=232 [1]
Link: https://gcc.gnu.org/wiki/Better_Uninitialized_Warnings [2]
Signed-off-by: Arnd Bergmann
Signed-off-by: Linus Torvalds
11 May, 2016
1 commit
-
gcc-6 started warning by default about variables that are not
used anywhere and that are marked 'const', generating many
false positives in an allmodconfig build, e.g.:arch/arm/mach-davinci/board-da830-evm.c:282:20: warning: 'da830_evm_emif25_pins' defined but not used [-Wunused-const-variable=]
arch/arm/plat-omap/dmtimer.c:958:34: warning: 'omap_timer_match' defined but not used [-Wunused-const-variable=]
drivers/bluetooth/hci_bcm.c:625:39: warning: 'acpi_bcm_default_gpios' defined but not used [-Wunused-const-variable=]
drivers/char/hw_random/omap-rng.c:92:18: warning: 'reg_map_omap4' defined but not used [-Wunused-const-variable=]
drivers/devfreq/exynos/exynos5_bus.c:381:32: warning: 'exynos5_busfreq_int_pm' defined but not used [-Wunused-const-variable=]
drivers/dma/mv_xor.c:1139:34: warning: 'mv_xor_dt_ids' defined but not used [-Wunused-const-variable=]This is similar to the existing -Wunused-but-set-variable warning
that was added in an earlier release and that we disable by default
now and only enable when W=1 is set, so it makes sense to do
the same here. Once we have eliminated the majority of the
warnings for both, we can put them back into the default list.We probably want this in backport kernels as well, to allow building
them with gcc-6 without introducing extra warnings.Signed-off-by: Arnd Bergmann
Acked-by: Olof Johansson
Acked-by: Lee Jones
Cc: stable@vger.kernel.org
Signed-off-by: Michal Marek
12 Jan, 2016
1 commit
-
Ideally, a kernel compile with W=1 enabled should complete cleanly;
however, when we run one currently we are presented with ~25k warnings.
'sign-compare' accounts for ~22k of those ~25k.In this patch we're demoting 'sign-compare' warnings to W=2, with a view
to fixing the remaining 3k W=1 warnings required for a clean build.Arnd adds:
"As per our discussion, I'd add that this was inadvertedly introduced
by Behan when he moved the clang specific warnings into an ifdef block
and did not notice that -Wsign-compare was interpreted by both gcc
and clang.Earlier, it was introduced in just the same way by Jan-Simon as part
of 3d3d6b847420 ("kbuild: LLVMLinux: Adapt warnings for compilation
with clang")."Acked-by: Arnd Bergmann
Fixes: 26ea6bb1fef0 ("kbuild, LLVMLinux: Supress warnings unless W=1-3")
Signed-off-by: Lee Jones
Signed-off-by: Michal Marek
04 Sep, 2015
1 commit
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We cannot detect clang before including the arch Makefile, because that
can set the default cross compiler. We also cannot detect clang after
including the arch Makefile, because powerpc wants to know about clang.
Solve this by using an deferred variable. This costs us a few shell
invocations, but this is only a constant number.Reported-by: Behan Webster
Reported-by: Anton Blanchard
Signed-off-by: Michal Marek
05 Aug, 2014
1 commit
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clang has more warnings enabled by default. Turn them off unless W is
set. This patch fixes a logic bug where warnings in clang were disabled
when W was set.Signed-off-by: Behan Webster
Signed-off-by: Jan-Simon Möller
Signed-off-by: Mark Charlebois
Cc: bp@alien8.de
Signed-off-by: Michal Marek
17 Apr, 2014
1 commit
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W=... provides extra gcc checks.
Having such code in scripts/Makefile.build results in the same flags
being added to KBUILD_CFLAGS multiple times becuase
scripts/Makefile.build is invoked every time Kbuild descends into
the subdirectories.Since the top Makefile is already too cluttered, this commit moves
all of extra gcc check stuff to a new file scripts/Makefile.extrawarn,
which is included from the top Makefile.Signed-off-by: Masahiro Yamada
CC: Sam Ravnborg
Signed-off-by: Michal Marek
