bn: use symtab for names

[williballenthin]

implement #1445 for Binary Ninja backend

[xusheng6]

I did an initial investigation on this, and I found that BN is already parsing the info from the symtab section properly. We just need to improve the extractor to provide the most accurate info.

For sample 2bf18d which is used in the unit test, I see BN already names the function at 0x4088a4 __libc_connect.

There are also symbols for connect and __GI_connect at the very same address, but if we call get_symbol_at with that address, only the __libc_connect is returned.

>>> bv.get_symbols_by_name('connect')
[<FunctionSymbol: "connect" @ 0x4088a4>]

>>> bv.get_symbols_by_name('__GI_connect')
[<FunctionSymbol: "__GI_connect" @ 0x4088a4>]

>>> bv.get_symbol_at(0x4088a4)
<FunctionSymbol: "__libc_connect" @ 0x4088a4>

I will checkout our doc and see how we could retrieve the three symbols with that address. I remember we already properly support multiple symbols at the same address.

[williballenthin]

neat, thank you!

[xusheng6]

We have an API get_symbols that allows the user to specify a start and end: https://api.binary.ninja/binaryninja.binaryview-module.html#binaryninja.binaryview.BinaryView.get_symbols. This API can return the multiple APIs at the same address