Re: [PATCH v2] travis-ci: enable more warnings on travis linux-gcc job
From: Jeff King <hidden>
Date: 2018-03-17 16:08:39
Subsystem:
kernel build + files below scripts/ (unless maintained elsewhere), the rest · Maintainers:
Nathan Chancellor, Nicolas Schier, Linus Torvalds
On Sat, Mar 17, 2018 at 03:59:23PM +0100, Duy Nguyen wrote:
On Sat, Mar 17, 2018 at 03:29:31PM +0100, Lars Schneider wrote:quoted
I interpreted Peff's comment like this: If DEVELOPER=1 is set and we detect a gcc-6 in the makefile, then we could set your additional flags in the makefile. This way every developer with a new compiler would run these flags locally (if DEVELOPER=1 is set).Aha. Something like this? I split developer cflags out to a separate file because I imagine people may start to add gcc7, clang....
Yeah, gcc 7 is already standard on debian unstable, so...
+GCC_VER := $(shell sh -c '$(CC) --version | grep ^gcc >/dev/null && $(CC) -dumpversion | cut -f 1 -d .') + +ifeq ($(GCC_VER),6)
...this probably needs to be "greater than or equal to". Unfortunately I think that's hard to do in pure make. But we're already relying on $(shell) here, so we could just move the logic there. Something like the patch below, perhaps. It should do the right thing on clang and gcc, and I added in an extra clang-only warning I've found useful. Otherwise the list of flags comes from your patch. The "clang4" limit is just what I happened to have on my system to test with. Some of those flags might work for clang3, and some of the gcc6-only flags might work on newer versions of clang. I was puzzled by -Wno-maybe-uninitialized, though. I think that has found bugs for us before (but also false positives, but we usually squelch those in the code). And it's part of -Wall, not -Wextra, so we shouldn't need it as part of this patch, should we?
diff --git a/Makefile b/Makefile
index a1d8775adb..9dfd152a1e 100644
--- a/Makefile
+++ b/Makefile@@ -442,15 +442,6 @@ GIT-VERSION-FILE: FORCE # CFLAGS and LDFLAGS are for the users to override from the command line. CFLAGS = -g -O2 -Wall -DEVELOPER_CFLAGS = -Werror \ - -Wdeclaration-after-statement \ - -Wno-format-zero-length \ - -Wold-style-definition \ - -Woverflow \ - -Wpointer-arith \ - -Wstrict-prototypes \ - -Wunused \ - -Wvla LDFLAGS = ALL_CFLAGS = $(CPPFLAGS) $(CFLAGS) ALL_LDFLAGS = $(LDFLAGS)
@@ -1051,7 +1042,7 @@ include config.mak.uname -include config.mak ifdef DEVELOPER -CFLAGS += $(DEVELOPER_CFLAGS) +include config.mak.dev endif comma := ,
diff --git a/config.mak.dev b/config.mak.dev
new file mode 100644
index 0000000000..59aef342c4
--- /dev/null
+++ b/config.mak.dev@@ -0,0 +1,28 @@ +CFLAGS += -Werror +CFLAGS += -Wdeclaration-after-statement +CFLAGS += -Wno-format-zero-length +CFLAGS += -Wold-style-definition +CFLAGS += -Woverflow +CFLAGS += -Wpointer-arith +CFLAGS += -Wstrict-prototypes +CFLAGS += -Wunused +CFLAGS += -Wvla + +COMPILER_FEATURES := $(shell ./detect-compiler $(CC)) + +ifneq ($(filter clang4,$(COMPILER_FEATURES)),) +CFLAGS += -Wtautological-constant-out-of-range-compare +endif + +ifneq ($(or $(filter gcc6,$(COMPILER_FEATURES)),$(filter clang4,$(COMPILER_FEATURES))),) +CFLAGS += -Wextra +CFLAGS += -Wmissing-prototypes +CFLAGS += -Wno-empty-body +CFLAGS += -Wno-missing-field-initializers +CFLAGS += -Wno-sign-compare +CFLAGS += -Wno-unused-function +CFLAGS += -Wno-unused-parameter +ifneq ($(filter gcc6,$(COMPILER_FEATURES)),) +CFLAGS += -Wno-maybe-uninitialized +endif +endif
diff --git a/detect-compiler b/detect-compiler
new file mode 100755
index 0000000000..043367828c
--- /dev/null
+++ b/detect-compiler@@ -0,0 +1,32 @@ +#!/bin/sh +# +# Probe the compiler for vintage, version, etc. This is used for setting +# optional make knobs under the DEVELOPER knob. + +CC="$*" + +print_flags() { + family=$1 + version=$($CC -dumpversion | cut -f 1 -d .) + + # Print a feature flag not only for the current version, but also + # for any prior versions we encompass. This avoids needing to do + # numeric comparisons in make, which are awkward. + while test "$version" -gt 0 + do + echo $family$version + version=$((version - 1)) + done +} + +case "$($CC --version 2>&1)" in +gcc*) + print_flags gcc + ;; +clang*) + print_flags clang + ;; +*) + : unknown compiler family + ;; +esac
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2.17.0.rc0.402.ged0b3fd1ee