Differential D1984
Add SRCS_SUBDIRS to allow Makefiles to put objects in subdirectories Authored by dim on Feb 28 2015, 1:50 AM. Tags None Referenced Files
Details We have some software in the base system that includes more than one file with the same name (in different directories). In some cases we wish to build these into a single library or program, which does not work with our current build infrastructure. This change allows the Makefile to set EXTRA_OBJDIRS to a list of subdirectories, and those paths can be included in SRCS. EXTRA_OBJDIRS=foo bar
SRCS=foo/file1.c \
bar/file1.cPutting in review for comments for now.
Diff Detail
Event TimelineComment Actions I understand the motivation, but this change makes me nervous. How will linkers find these moved files? Comment Actions Linking is not a problem because the transformation for ${OBJS} leaves the subdir intact: OBJS+= ${SRCS:N*.h:R:S/$/.o/g} The link ends up looking like: cc -O2 -pipe -std=gnu99 -fstack-protector -Qunused-arguments -o test foo/file.o bar/file.o There is one caveat, the double-suffix rules in sys.mk do not include the -o argument: .c.o:
${CC} ${CFLAGS} -c ${.IMPSRC}
${CTFCONVERT_CMD}so the object file ends up in ${CANONICALOBJDIR}, not the subdirectory. I did not notice this before because bsd.lib.mk provides its own double-suffix rules that do include -o: .cc.o .C.o .cpp.o .cxx.o:
${CXX} ${STATIC_CXXFLAGS} ${CXXFLAGS} -c ${.IMPSRC} -o ${.TARGET}and the case I've been testing here is working on building a single libllvm With sys.mk updated to specify -o and this example Makefile: PROG=test SRCS=foo/file.c bar/file.c MAN= .include <bsd.prog.mk> the output looks like: joule% make cc -O2 -pipe -std=gnu99 -fstack-protector -Qunused-arguments -c foo/file.c -o foo/file.o cc -O2 -pipe -std=gnu99 -fstack-protector -Qunused-arguments -c bar/file.c -o bar/file.o cc -O2 -pipe -std=gnu99 -fstack-protector -Qunused-arguments -o test foo/file.o bar/file.o I will upload a new diff later on with sys.mk changes incorporated.
Comment Actions
Comment Actions How does this work with 'reach over' sources? Comment Actions I assume you mean with multiple settings of .PATH? It should work fine, although is not a use case that's motivating this.
Yeah, it wasn't immediately obvious to me how that could be done in make syntax, but it turns out it's not too bad with something like ${SRCS:M*/*:C/(^.*)\/[^\/]*$/\1/} Comment Actions If you aren't worried about / or ../ starting src files, it's simpler to say: Comment Actions I'm not convinced that an explicit SRCS_SUBDIRS adds value. In CheriBSD we're just building it internally with an expression like imp suggests. See: https://github.com/CTSRD-CHERI/cheribsd/commit/c29c584dbde5597cb6af232cdcfa192138ba534e The one caution with this change is that you must run "make obj" in the directory (or use buildworld et al to do it for you) or all sorts of weird things happen. With projects/bmake we're moving toward mandatory objdirs so I think this is fine, but there may be some confusion. Comment Actions I'd only made the change to create the object dirs. The change to explicitly use -o ${.TARGET} was done as a local makefile hack rather than doing in sys.mk where it belongs.
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