Re: [PATCH 1/1] MINOR: build: force CC to set a return code when probing options
Hi Bertrand, On Sat, Mar 06, 2021 at 08:25:46PM +, Bertrand Jacquin wrote: > gcc returns non zero code if an option is not supported (tested > from 6.5 to 10.2). > > $ gcc -Wfoobar -E -xc - -o /dev/null < /dev/null > /dev/null 2>&1 ; echo $? > 1 > > clang always return 0 if an option in not recognized unless > -Werror is also passed, preventing a correct probing of options > supported by the compiler (tested with clang 6.0.1 to 11.1.0). > > $ clang -Wfoobar -E -xc - -o /dev/null < /dev/null > /dev/null 2>&1 ; echo > $? > 0 > $ clang -Werror -Wfoobar -E -xc - -o /dev/null < /dev/null > /dev/null 2>&1 > ; echo $? > 1 That's interesting, because we've constantly been complaining about gcc not accepting random -Wfoobar and requiring runtime discovery, but on the other hand, not having any info about support is a problem as well. I can indeed imagine that we could enable -Werror=some-option-about-commandline but that would require to detect it, so I think that -Werror indeed remains an acceptable solution here. > Please note today this is not visible since clang 11 exit with SIGABRT > or with return code 1 on older version due to bad file descriptor from > file descriptor handling > > $ clang -Wfoobar -E -xc - -o /dev/null < /dev/null 2>&0 ; echo $? > Aborted (core dumped) > 134 This is particularly ugly, I can imagine how annoying it can become if a tens of cores are produced upon every single haproxy build. Let's hope they quickly fix it. Thanks for the explanation, I'm taking your patch! Willy
Re: [PATCH 1/1] MINOR: build: force CC to set a return code when probing options
Hello Bertrand, On Sun, 7 Mar 2021 at 00:53, Bertrand Jacquin wrote: > I am not proposing haproxy build-system to use -Werror here, I'm only > proposing to use -Werror when probing for options supported by the > compiler, as effectively clang return a code if 0 even if an option is > not supported. The fact haproxy does not use -Wno-clobbered today is > with clang build because of an internal bug in clang with how haproxy is > using stdin/stderr indirection. > > With the proposal above, Werror is only use to probe options, it is not > reflected in SPEC_CFLAGS. Got it, thanks for clarifying. Lukas
Re: [PATCH 1/1] MINOR: build: force CC to set a return code when probing options
Hi Lukas, On Saturday, March 06 2021 at 23:48:52 +0100, Lukas Tribus wrote: > Hello, > > On Sat, 6 Mar 2021 at 21:25, Bertrand Jacquin wrote: > > > > gcc returns non zero code if an option is not supported (tested > > from 6.5 to 10.2). > > > > $ gcc -Wfoobar -E -xc - -o /dev/null < /dev/null > /dev/null 2>&1 ; echo > > $? > > 1 > > > > clang always return 0 if an option in not recognized unless > > -Werror is also passed, preventing a correct probing of options > > supported by the compiler (tested with clang 6.0.1 to 11.1.0) > > -Werror is more than just "-Wunknown-warning-option" on clang. > -Werror/ERR is specifically optional in the Makefile. > > If we want to change the haproxy build-system to do -Werror from now > on we need a) discuss it and b) fix it all up. We can't hardcode > -Werror and at the same time claim that it's an optional parameter. I am not proposing haproxy build-system to use -Werror here, I'm only proposing to use -Werror when probing for options supported by the compiler, as effectively clang return a code if 0 even if an option is not supported. The fact haproxy does not use -Wno-clobbered today is with clang build because of an internal bug in clang with how haproxy is using stdin/stderr indirection. With the proposal above, Werror is only use to probe options, it is not reflected in SPEC_CFLAGS. -- Bertrand
Re: [PATCH 1/1] MINOR: build: force CC to set a return code when probing options
Hello, On Sat, 6 Mar 2021 at 21:25, Bertrand Jacquin wrote: > > gcc returns non zero code if an option is not supported (tested > from 6.5 to 10.2). > > $ gcc -Wfoobar -E -xc - -o /dev/null < /dev/null > /dev/null 2>&1 ; echo $? > 1 > > clang always return 0 if an option in not recognized unless > -Werror is also passed, preventing a correct probing of options > supported by the compiler (tested with clang 6.0.1 to 11.1.0) -Werror is more than just "-Wunknown-warning-option" on clang. -Werror/ERR is specifically optional in the Makefile. If we want to change the haproxy build-system to do -Werror from now on we need a) discuss it and b) fix it all up. We can't hardcode -Werror and at the same time claim that it's an optional parameter. Lukas
[PATCH 1/1] MINOR: build: force CC to set a return code when probing options
gcc returns non zero code if an option is not supported (tested from 6.5 to 10.2). $ gcc -Wfoobar -E -xc - -o /dev/null < /dev/null > /dev/null 2>&1 ; echo $? 1 clang always return 0 if an option in not recognized unless -Werror is also passed, preventing a correct probing of options supported by the compiler (tested with clang 6.0.1 to 11.1.0). $ clang -Wfoobar -E -xc - -o /dev/null < /dev/null > /dev/null 2>&1 ; echo $? 0 $ clang -Werror -Wfoobar -E -xc - -o /dev/null < /dev/null > /dev/null 2>&1 ; echo $? 1 Please note today this is not visible since clang 11 exit with SIGABRT or with return code 1 on older version due to bad file descriptor from file descriptor handling $ clang -Wfoobar -E -xc - -o /dev/null < /dev/null 2>&0 ; echo $? Aborted (core dumped) 134 $ clang -Wfoobar -E -xc - -o /dev/null < /dev/null ; echo $? warning: unknown warning option '-Wfoobar'; did you mean '-Wformat'? [-Wunknown-warning-option] 1 warning generated. 0 $ clang-11 -Werror -Wfoobar -E -xc - -o /dev/null < /dev/null ; echo $? error: unknown warning option '-Wfoobar'; did you mean '-Wformat'? [-Werror,-Wunknown-warning-option] 1 This specific issue is being tracked with clang upstream in https://bugs.llvm.org/show_bug.cgi?id=49463 --- Makefile | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/Makefile b/Makefile index 77960ba4cac5..0867047fdc69 100644 --- a/Makefile +++ b/Makefile @@ -126,16 +126,16 @@ endif # Usage: CFLAGS += $(call cc-opt,option). Eg: $(call cc-opt,-fwrapv) # Note: ensure the referencing variable is assigned using ":=" and not "=" to # call it only once. -cc-opt = $(shell set -e; if $(CC) $(1) -E -xc - -o /dev/null &0 2>&0; then echo "$(1)"; fi;) +cc-opt = $(shell set -e; if $(CC) -Werror $(1) -E -xc - -o /dev/null &0 2>&0; then echo "$(1)"; fi;) # same but emits $2 if $1 is not supported -cc-opt-alt = $(shell set -e; if $(CC) $(1) -E -xc - -o /dev/null &0 2>&0; then echo "$(1)"; else echo "$(2)"; fi;) +cc-opt-alt = $(shell set -e; if $(CC) -Werror $(1) -E -xc - -o /dev/null &0 2>&0; then echo "$(1)"; else echo "$(2)"; fi;) # Disable a warning when supported by the compiler. Don't put spaces around the # warning! And don't use cc-opt which doesn't always report an error until # another one is also returned. # Usage: CFLAGS += $(call cc-nowarn,warning). Eg: $(call cc-opt,format-truncation) -cc-nowarn = $(shell set -e; if $(CC) -W$(1) -E -xc - -o /dev/null &0 2>&0; then echo "-Wno-$(1)"; fi;) +cc-nowarn = $(shell set -e; if $(CC) -Werror -W$(1) -E -xc - -o /dev/null &0 2>&0; then echo "-Wno-$(1)"; fi;) Installation options. DESTDIR =
