From 731b6859c41de0e03ff99c704db4bb621a87fb88 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=C3=86var=20Arnfj=C3=B6r=C3=B0=20Bjarmason?= Date: Thu, 23 Sep 2021 00:08:01 +0200 Subject: [PATCH] Makefile: make COMPUTE_HEADER_DEPENDENCIES=auto work with DEVOPTS=pedantic MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The "COMPUTE_HEADER_DEPENDENCIES" feature added in [1] was extended to use auto-detection in [2], that "auto" detection has always piped STDERR to /dev/null, so any failures on compilers that didn't support these GCC flags would silently fall back to "COMPUTE_HEADER_DEPENDENCIES=no". Later when -Wpedantic support was added to DEVOPTS in [3] we started passing -Wpedantic in combination with -Werror to the compiler here. Note (to the pedantic): [3] actually passed "-pedantic", but it and "-Wpedantic" are synonyms. Turning on -Wpedantic in [3] broke the auto-detection, since this relies on compiling an empty program. GCC would loudly complain on STDERR: /dev/null:1: error: ISO C forbids an empty translation unit [-Werror=pedantic] cc1: note: unrecognized command-line option ‘-Wno-pedantic-ms-format’ may have been intended to silence earlier diagnostics cc1: all warnings being treated as errors But as that ended up in the "$(dep_check)" variable due to the "2>&1" in [2] we didn't see it. Then when [4] made DEVOPTS=pedantic the default specifying "DEVELOPER=1" would effectively set "COMPUTE_HEADER_DEPENDENCIES=no". To fix these issues let's unconditionally pass -Wno-pedantic after $(ALL_CFLAGS), we might get a -Wpedantic via config.mak.dev after, or the builder might specify it via CFLAGS. In either case this will undo current and future problems with -Wpedantic. I think it would make sense to simply remove the "2>&1", it would mean that anyone using a non-GCC-like compiler would get warnings under COMPUTE_HEADER_DEPENDENCIES=auto, e.g on AIX's xlc would emit: /opt/IBM/xlc/13.1.3/bin/.orig/xlc: 1501-208 (S) command option D is missing a subargument Non-zero 40 exit with COMPUTE_HEADER_DEPENDENCIES=auto, set it to "yes" or "no" to quiet auto-detect And on Solaris with SunCC: cc: Warning: Option -x passed to ld, if ld is invoked, ignored otherwise cc: refused to overwrite input file by output file: /dev/null cc: Warning: Option -x passed to ld, if ld is invoked, ignored otherwise cc: refused to overwrite input file by output file: /dev/null Non-zero 1 exit with COMPUTE_HEADER_DEPENDENCIES=auto, set it to "yes" or "no" to quiet auto-detect Both could be quieted by setting COMPUTE_HEADER_DEPENDENCIES=no explicitly, as suggested, but let's see if this'll fix it without emitting too much noise at those that aren't using "gcc" or "clang". 1. f2fabbf76e4 (Teach Makefile to check header dependencies, 2010-01-26) 2. 111ee18c31f (Makefile: Use computed header dependencies if the compiler supports it, 2011-08-18) 3. 729b3925ed9 (Makefile: add a DEVOPTS flag to get pedantic compilation, 2018-07-24) 4. 6a8cbc41bac (developer: enable pedantic by default, 2021-09-03) Signed-off-by: Ævar Arnfjörð Bjarmason Signed-off-by: Junio C Hamano --- Makefile | 1 + 1 file changed, 1 insertion(+) diff --git a/Makefile b/Makefile index 9df565f27b..10ea12aae2 100644 --- a/Makefile +++ b/Makefile @@ -1278,6 +1278,7 @@ endif ifeq ($(COMPUTE_HEADER_DEPENDENCIES),auto) dep_check = $(shell $(CC) $(ALL_CFLAGS) \ + -Wno-pedantic \ -c -MF /dev/null -MQ /dev/null -MMD -MP \ -x c /dev/null -o /dev/null 2>&1; \ echo $$?)