Better gadget filtering in RegSetter

[Kyle-Kyle]

Description

Currently, there are a lot of noisy gadgets in reg_setter. (such as pop rbp; add dh, dh; ret when there is pop rbp; ret. This is caused by the need to do basic register arithmetic. This is slowing us down when we need to try different gadgets.
Moving the register arithmetic logic out of RegSetter will make it cleaner and we will have the chance of doing register arithmetic properly

Alternatives

No response

Additional context

No response

[Kyle-Kyle]

when it happens, use the following as testcase:

def test_gadget_filtering():
    proj = angr.load_shellcode(
        """ 
        pop rbp; add dh, dh; ret 
        pop rbp; or dh, dh; ret 
        pop rbp; add cl, ch; ret 
        pop rbp; sub al, 0xf6; ret 
        pop rbp; or al, ch; ret 
        pop rbp; add bl, ch; ret 
        pop rbp; ret 
        pop rbp; add bh, dh; ret 
        pop rbp; and dh, dh; ret 
        pop rbp; and bh, dh; ret 
        pop rbp; ret 
        shr cl, 0x99; pop rbp; ret 
        cdq ; pop rbp; ret 
        imul al; pop rbp; ret 
        shr cl, 0x3f; pop rbp; ret 
        xor eax, 0x7502e383; cmp cl, byte ptr [rax - 0x75]; pop rbp; add bh, dh; ret 
        """,
        "amd64",
        load_address=0x400000,
        auto_load_libs=False,
    )   
    rop = proj.analyses.ROP()
    rop.find_gadgets_single_threaded(show_progress=False)
    assert len(rop.chain_builder._reg_setter._reg_setting_dict['rbp']) == 1
    assert rop.chain_builder._reg_setter._reg_setting_dict['rbp'][0].dstr().strip() == "pop rbp; ret"

[Kyle-Kyle]

when it happens. we also need to use the following testcase to make sure it does not hang when handling huge concrete data

def test_hard_regs_loop():
    cache_path = os.path.join(data_dir, "bronze_ropchain")
    proj = angr.Project(os.path.join(tests_dir, "i386", "bronze_ropchain"), auto_load_libs=False)
    rop = proj.analyses.ROP()

    if os.path.exists(cache_path):
        rop.load_gadgets(cache_path, optimize=False)
    else:
        rop.find_gadgets()

    rop.set_badbytes([0x00, 0x0A])
    chain = rop.set_regs(eax=0x4200009a, edx=0xdeadbefc)
    chain.pp()