From: Nathan Chancellor <natechancellor@gmail.com>
To: Masahiro Yamada <masahiroy@kernel.org>,
Michal Marek <michal.lkml@markovi.net>,
Arnd Bergmann <arnd@arndb.de>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>, Jason Baron <jbaron@akamai.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org,
linux-arch@vger.kernel.org, linux-mm@kvack.org,
clang-built-linux@googlegroups.com,
Nathan Chancellor <natechancellor@gmail.com>
Subject: [PATCH 6/6] kbuild: Enable -Wtautological-compare
Date: Tue, 18 Feb 2020 21:54:23 -0700
Message-ID: <20200219045423.54190-7-natechancellor@gmail.com> (raw)
In-Reply-To: <20200219045423.54190-1-natechancellor@gmail.com>
Currently, we disable -Wtautological-compare, which in turn disables a
bunch of more specific tautological comparison warnings that are useful
for the kernel (see clang's documentation below). Now that all of the
major/noisy warnings have been fixed, enable -Wtautological-compare so
that more issues can be caught at build time.
-Wtautological-constant-out-of-range-compare is kept disabled 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 they are almost always harmless so this one
subwarning is kept disabled.
Link: https://github.com/ClangBuiltLinux/linux/issues/488
Link: http://releases.llvm.org/9.0.0/tools/clang/docs/DiagnosticsReference.html#wtautological-compare
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---
Makefile | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/Makefile b/Makefile
index b954c304c479..99080c57a1cb 100644
--- a/Makefile
+++ b/Makefile
@@ -742,8 +742,7 @@ ifdef CONFIG_CC_IS_CLANG
KBUILD_CPPFLAGS += -Qunused-arguments
KBUILD_CFLAGS += -Wno-format-invalid-specifier
KBUILD_CFLAGS += -Wno-gnu
-# Quiet clang warning: comparison of unsigned expression < 0 is always false
-KBUILD_CFLAGS += -Wno-tautological-compare
+KBUILD_CFLAGS += -Wno-tautological-constant-out-of-range-compare
# CLANG uses a _MergedGlobals as optimization, but this breaks modpost, as the
# source of a reference will be _MergedGlobals and not on of the whitelisted names.
# See modpost pattern 2
--
2.25.1
next prev parent reply index
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-19 4:54 [PATCH 0/6] Silence some instances of -Wtautological-compare and enable globally Nathan Chancellor
2020-02-19 4:54 ` [PATCH 1/6] asm/sections: Add COMPARE_SECTIONS macro Nathan Chancellor
2020-02-19 4:54 ` [PATCH 2/6] kernel/extable: Wrap section comparison in sort_main_extable with COMPARE_SECTIONS Nathan Chancellor
2020-02-19 4:54 ` [PATCH 3/6] tracing: Wrap section comparison in tracer_alloc_buffers " Nathan Chancellor
2020-02-19 14:34 ` Steven Rostedt
2020-02-19 17:44 ` Nick Desaulniers
2020-02-19 18:16 ` Jason Gunthorpe
2020-02-19 19:09 ` Steven Rostedt
2020-02-19 19:11 ` Nick Desaulniers
2020-02-19 19:22 ` Nathan Chancellor
2020-02-19 19:43 ` Steven Rostedt
2020-02-19 19:54 ` Jason Gunthorpe
2020-02-19 21:32 ` Nick Desaulniers
2020-02-19 4:54 ` [PATCH 4/6] dynamic_debug: Wrap section comparison in dynamic_debug_init " Nathan Chancellor
2020-02-19 4:54 ` [PATCH 5/6] mm: kmemleak: Wrap section comparison in kmemleak_init " Nathan Chancellor
2020-02-19 4:54 ` Nathan Chancellor [this message]
2020-04-21 4:03 ` [PATCH 0/6] Silence some instances of -Wtautological-compare and enable globally Andrew Morton
2020-04-21 4:32 ` Nathan Chancellor
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