On 10/26/20 6:10 PM, Eric Biggers wrote: > [+Jes Sorensen] > > On Mon, Oct 26, 2020 at 08:48:31PM +0000, luca.boccassi@xxxxxxxxx wrote: >> From: Romain Perier <romain.perier@xxxxxxxxx> >> >> Currently, CFLAGS are defined by default. It has to effect to define its >> c-compiler options only when the variable is not defined on the cmdline >> by the user, it is not possible to merge or mix both, while it could >> be interesting for using the app warning cflags or the pkg-config >> cflags, while using the distributor flags. Most distributions packages >> use their own compilation flags, typically for hardening purpose but not >> only. This fixes the issue by using the override keyword. >> >> Signed-off-by: Romain Perier <romain.perier@xxxxxxxxx> >> --- >> Currently used in Debian, were we want to append context-specific >> compiler flags (eg: for compiler hardening options) without >> removing the default flags >> >> Makefile | 5 +++-- >> 1 file changed, 3 insertions(+), 2 deletions(-) >> >> diff --git a/Makefile b/Makefile >> index 6c6c8c9..5020cac 100644 >> --- a/Makefile >> +++ b/Makefile >> @@ -35,14 +35,15 @@ >> cc-option = $(shell if $(CC) $(1) -c -x c /dev/null -o /dev/null > /dev/null 2>&1; \ >> then echo $(1); fi) >> >> -CFLAGS ?= -O2 -Wall -Wundef \ >> +override CFLAGS := -O2 -Wall -Wundef \ >> $(call cc-option,-Wdeclaration-after-statement) \ >> $(call cc-option,-Wimplicit-fallthrough) \ >> $(call cc-option,-Wmissing-field-initializers) \ >> $(call cc-option,-Wmissing-prototypes) \ >> $(call cc-option,-Wstrict-prototypes) \ >> $(call cc-option,-Wunused-parameter) \ >> - $(call cc-option,-Wvla) >> + $(call cc-option,-Wvla) \ >> + $(CFLAGS) >> >> override CPPFLAGS := -Iinclude -D_FILE_OFFSET_BITS=64 $(CPPFLAGS) > > I had it like this originally, but Jes requested that it be changed to the > current way for rpm packaging. See the thread: > https://lkml.kernel.org/linux-fscrypt/20200515205649.1670512-3-Jes.Sorensen@xxxxxxxxx/T/#u > > Can we come to an agreement on one way to do it? > > To me, the approach with 'override' makes more sense. The only non-warning > option is -O2, and if someone doesn't want that, they can just specify > CFLAGS=-O0 and it will override -O2 (since the last option "wins"). > > Jes, can you explain why that way doesn't work with rpm? I don't remember all the details and I haven't looked at this in a while. Matthew Almond has helpfully offered to look into it. Jes
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