• Andrey Ignatov's avatar
    libbpf: Add version script for DSO · 16192a77
    Andrey Ignatov authored
    More and more projects use libbpf and one day it'll likely be packaged
    and distributed as DSO and that requires ABI versioning so that both
    compatible and incompatible changes to ABI can be introduced in a safe
    way in the future without breaking executables dynamically linked with a
    previous version of the library.
    
    Usual way to do ABI versioning is version script for the linker. Add
    such a script for libbpf. All global symbols currently exported via
    LIBBPF_API macro are added to the version script libbpf.map.
    
    The version name LIBBPF_0.0.1 is constructed from the name of the
    library + version specified by $(LIBBPF_VERSION) in Makefile.
    
    Version script does not duplicate the work done by LIBBPF_API macro, it
    rather complements it. The macro is used at compile time and can be used
    by compiler to do optimization that can't be done at link time, it is
    purely about global symbol visibility. The version script, in turn, is
    used at link time and takes care of ABI versioning. Both techniques are
    described in details in [1].
    
    Whenever ABI is changed in the future, version script should be changed
    appropriately.
    
    [1] https://www.akkadia.org/drepper/dsohowto.pdfSigned-off-by: default avatarAndrey Ignatov <rdna@fb.com>
    Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
    16192a77
Makefile 6.62 KB