Commit 6d5d4b4e authored by Committed by Junio C Hamano
Makefile: allow for combining DEVELOPER=1 and CFLAGS="..."
Ever since the DEVELOPER=1 facility introduced there's been no way to have custom CFLAGS (e.g. CFLAGS="-O0 -g -ggdb3") while still benefiting from the set of warnings and assertions DEVELOPER=1 enables. This is because the semantics of variables in the Makefile are such that the user setting CFLAGS overrides anything we set, including what we're doing in config.mak.dev. So let's introduce a "DEVELOPER_CFLAGS" variable in config.mak.dev and add it to ALL_CFLAGS. Before this the ALL_CFLAGS variable would (basically, there's some nuance we won't go into) be set to: $(CPPFLAGS) [$(CFLAGS) *or* $(CFLAGS) in config.mak.dev] $(BASIC_CFLAGS) $(EXTRA_CPPFLAGS) But will now be: $(DEVELOPER_CFLAGS) $(CPPFLAGS) $(CFLAGS) $(BASIC_CFLAGS) $(EXTRA_CPPFLAGS) The reason for putting DEVELOPER_CFLAGS first is to allow for selectively overriding something DEVELOPER=1 brings in. On both GCC and Clang later settings override earlier ones. E.g. "-Wextra -Wno-extra" will enable no "extra" warnings, but not if those two arguments are reversed. Examples of things that weren't possible before, but are now: # Use -O0 instead of -O2 for less painful debuggng DEVELOPER=1 CFLAGS="-O0 -g" # DEVELOPER=1 plus -Wextra, but disable some of the warnings DEVELOPER=1 DEVOPTS="no-error extra-all" CFLAGS="-O0 -g -Wno-unused-parameter" The reason for the patches leading up to this one re-arranged the various *FLAGS assignments and includes is just for readability. The Makefile supports assignments out of order, e.g.: $ cat Makefile X = $(A) $(B) $(C) A = A B = B include c.mak all: @echo $(X) $ cat c.mak C=C $ make A B C So we could have gotten away with the much smaller change of changing "CFLAGS" in config.mak.dev to "DEVELOPER_CFLAGS" and adding that to ALL_CFLAGS earlier in the Makefile "before" the config.mak.* includes. But I think it's more readable to use variables "after" they're included. 1. https://www.gnu.org/software/make/manual/html_node/Overriding.htmlSigned-off-by: Ævar Arnfjörð Bjarmason <firstname.lastname@example.org> Signed-off-by: Junio C Hamano <email@example.com>
Showing with 28 additions and 24 deletions