NetBSD supports a number of platforms where both 32bit and 64bit execution is possible. The more well known example is the i386/AMD64 pair and the other important one is SPARC/SPARC64. On this platforms it is highly desirable to allow running all 32bit applications with a 64bit kernel. This is the purpose of the netbsd32 compatibility layer.

At the moment, the netbsd32 layer consists of a number of system call stubs and structure definitions written and maintained by hand. It is hard to ensure that the stubs and definitions are up-to-date and correct. One complication is the difference in alignment rules. On i386 uint64_t has a 32bit alignment, but on AMD64 it uses natural (64bit) alignment. This and the resulting padding introduced by the compiler can create hard to find bugs.


For this purpose, the Clang C parser or the libclang frontend can be used to analyse the C code.