http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46489
--- Comment #5 from Jorn Wolfgang Rennecke <amylaar at gcc dot gnu.org> 2010-12-20 17:04:39 UTC --- (In reply to comment #4) > This sounds like a nice approach for making sure it is safe to remove a > tm.h include from a particular source file - if combined with generating a > list of every target (every triplet with significant differences in how > config.gcc / libgcc/config.host configure it, whether in the set of > headers or the set of tm_defines) so you can run tests automatically for > all targets - I fear our configure system is turing complete, and thus such a list is not computable. But by testing at least one configuration per target architecture, we already get a useful test coverage. I can also make a script to search for every macro that is documented with @defmac, so the remaining uncertainty would be for undocumented macros that only appear in specific configuration variants. I think a slight risk to break something where undocumented macros are involved is acceptable in phase 1/2, as long as the breakage is obvious during the gcc build - without the target macro poisoning, we could have obscure changes in behaviour that could be very hard to debug. > it may avoid the need to check for every macro with one of > the properties I identified as meaning a target macro, that is used > anywhere in that source file or any header it includes. I'd be more > doubtful about actually checking in a #include of tm-poison.h on trunk > (the code to generate it, however, might be useful to check in). Yes, the idea is to auto-generate the file.
