Dealing with two stack variables

[a-hamza-r]

Multiple programs in the repository, including twostackvars, and ovs/datapath.o, sections: [tail-1, tail-4, tail-5, tail-7, tail-8, tail-11, tail-13] dead with two stack pointers (at different offsets) joined. It is usually followed by a lookup for numeric value at the stack pointer offset in the joined basic block. It is likely to fail because if the numbers were at different offsets, they are forgotten during join. For this purpose, the eBPF (zoneCrab domain) has stack_numeric_size variable with each stack variable that computes how many bytes after the stack_offset, the bytes are numeric. In eBPF, the check succeeds. However, type domain does not, for the given benchmarks.
Link to pull request for stack_numeric_size-related discussion: vbpf#292