[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen master] build: make cc-option properly deal with unrecognized sub-options
commit 824b5a40dd3de0bd58fa306f4be8d6e13e1c327d Author: Jan Beulich <jbeulich@xxxxxxxx> AuthorDate: Wed Aug 23 09:25:52 2023 +0200 Commit: Jan Beulich <jbeulich@xxxxxxxx> CommitDate: Wed Aug 23 09:25:52 2023 +0200 build: make cc-option properly deal with unrecognized sub-options In options like -march=, it may be only the sub-option which is unrecognized by the compiler. In such an event the error message often splits option and argument, typically saying something like "bad value '<argument>' for '<option>'. Instead of extend the grep invocation, stop parsing compiler output altogether. Instead substitute -Wno-* options by their -W* counterparts for probing (obviously assuming that such a counterpart always exists). Suggested-by: Anthony PERARD <anthony.perard@xxxxxxxxxx> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> Reviewed-by: Anthony PERARD <anthony.perard@xxxxxxxxxx> --- Config.mk | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/Config.mk b/Config.mk index dc3afaa47e..29c29f8d7f 100644 --- a/Config.mk +++ b/Config.mk @@ -85,17 +85,17 @@ PYTHON_PREFIX_ARG ?= --prefix="$(prefix)" # cc-option: Check if compiler supports first option, else fall back to second. # -# This is complicated by the fact that unrecognised -Wno-* options: +# This is complicated by the fact that with most gcc versions unrecognised +# -Wno-* options: # (a) are ignored unless the compilation emits a warning; and # (b) even then produce a warning rather than an error -# To handle this we do a test compile, passing the option-under-test, on a code -# fragment that will always produce a warning (integer assigned to pointer). -# We then grep for the option-under-test in the compiler's output, the presence -# of which would indicate an "unrecognized command-line option" warning/error. +# Further Clang also only warns for unrecognised -W* options. To handle this +# we do a test compile, substituting -Wno-* by -W* and adding -Werror. This +# way all unrecognised options are diagnosed uniformly, allowing us to merely +# check exit status. # # Usage: cflags-y += $(call cc-option,$(CC),-march=winchip-c6,-march=i586) -cc-option = $(shell if test -z "`echo 'void*p=1;' | \ - $(1) $(2) -c -o /dev/null -x c - 2>&1 | grep -- $(2:-Wa$(comma)%=%) -`"; \ +cc-option = $(shell if $(1) $(2:-Wno-%=-W%) -Werror -c -o /dev/null -x c /dev/null >/dev/null 2>&1; \ then echo "$(2)"; else echo "$(3)"; fi ;) # cc-option-add: Add an option to compilation flags, but only if supported. -- generated by git-patchbot for /home/xen/git/xen.git#master
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