Bruno Haible <br...@clisp.org> writes: > Arsen Arsenović wrote: >> An alternative that I pondered was to teach the linker about some notion >> of "compatibility strings" that it would compare and reject if >> different, plus teaching the compiler how to emit those, plus teaching >> glibc to tell the compiler to emit those.. We could have key-value >> pairs in some section. For each key K, we could have the linker check >> that, for each (shared or otherwise) object either does not contain K or >> contains K with the same value as all the other ones, and produce an >> error otherwise. On the resulting object, the KV pairs would be the >> union of all KV pairs of all constituent objects. > > This sounds much like the arm eabi attributes: If a .s file does not > start with > .eabi_attribute 20, 1 > .eabi_attribute 21, 1 > .eabi_attribute 23, 3 > .eabi_attribute 24, 1 > .eabi_attribute 25, 1 > .eabi_attribute 26, 2 > .eabi_attribute 30, 2 > .eabi_attribute 34, 0 > .eabi_attribute 18, 4 > the resulting .o file cannot be linked with other .o files on the system. > > Is it a hassle even for packages that don't use time_t of off_t (such as > GNU libffcall or libffi). > > Yes, it would be useful to have a way to have the linker warn if a binary > that depends on 32-bit time_t and a binary that depends on 64-bit time_t > get linked together. But PLEASE implement this in a way that is a no-op > when time_t is not used by either of the two binaries.
I mentioned that a missing pair should not preclude linking. This is because what I imagined is somehow attaching this tag to the typedef for time_t, or such, so if the typedef is not used, no such tag is emitted. I'm not sure how feasible that is, I, of course, don't have a full implementation. -- Arsen Arsenović
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