On Sat, Aug 15, 2015 at 6:45 PM, Mark Johnston <ma...@freebsd.org> wrote: > There seems to be a bug in the make rules when DTrace is enabled. It > causes dtrace -G to be invoked twice when building PostgreSQL as a > FreeBSD port: once during the build itself, and once during > installation. For a long time this has been worked around on FreeBSD > with a change to libdtrace itself, but this workaround is proving > problematic and I'd like to fix the problem properly. I'm not sure > whether the problem has been observed on other operating systems that > support DTrace. > > The bug is in src/backend/Makefile. probes.o, the dtrace(1)-generated > object file, depends on the objfiles.txt for each of the backend > subdirs. These files depend in turn on the object files themselves; if > objfiles.txt is out of date with respect to one of its object files, the > mtime of objfiles.txt is updated with "touch" (see backend/common.mk). > The problem is that dtrace -G, which runs at the end of the build, > modifies a number of object files (it overwrites their probe sites with > NOPs), thus making their corresponding objfiles.txt out of date. Then, > when "make install" traverses the backend subdirs, it updates > objfiles.txt, which causes probes.o to be rebuilt, resulting in an error > from dtrace(1).
Gosh, that's pretty ugly. I would have thought it would be a real no-no to update the .o file once it got generated. If nothing else, a modification to the .c file concurrent with a make invocation might lead to the .o not getting rebuilt the next time make is run. > The attached patch fixes the problem by having probes.o depend on object > files directly, rather than on objfiles.txt. I've tested it with > PostgreSQL 9.0-9.4 on FreeBSD CURRENT. I don't see a particular reason not to make this change, though. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
