├── README.md
└── objc-stub-fixer.py


/README.md:
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 1 | ### Hopper Objective-C Method Stub Fixer
 2 | 
 3 | #### Description
 4 | 
 5 | This script for Hopper Disassembler identifies and renames Objective-C method stubs using their selector names.
 6 | 
 7 | 
 8 | ![Before_and_After_Comparison](https://github.com/EthanArbuckle/Hopper-Objective-C-Stub-Fixer/assets/4250718/ca44cca4-2cef-459a-9e8a-66a89b68d95f)
 9 | 
10 | 
11 | https://github.com/EthanArbuckle/Hopper-Objective-C-Stub-Fixer/assets/4250718/cf5fae93-9525-4ca0-8c74-6ac435d36a7e
12 | 
13 | 


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/objc-stub-fixer.py:
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  1 | from typing import Optional
  2 | 
  3 | 
  4 | def read_c_string(doc: Document, address: int) -> str:
  5 |     """
  6 |     Read a null-terminated C string from the document at the given address.
  7 |     """
  8 |     result = bytearray()
  9 |     while True:
 10 |         byte = doc.readByte(address)
 11 |         if byte == 0:
 12 |             break
 13 |         result.append(byte)
 14 |         address += 1
 15 |     return result.decode()
 16 | 
 17 | 
 18 | def is_objc_stub(doc: Document, address: int) -> bool:
 19 |     """
 20 |     Check if the function at the given address is an Objective-C stub.
 21 |     """
 22 |     seg = doc.getCurrentSegment()
 23 |     instructions = [seg.getInstructionAtAddress(address + i * 4) for i in range(5)]
 24 |     if any(inst is None for inst in instructions):
 25 |         return False
 26 | 
 27 |     instruction_strings = [inst.getInstructionString() for inst in instructions]
 28 |     expected_instructions = ["adrp", "ldr", "adrp", "ldr", "br"]
 29 |     return all(inst.startswith(expected) for inst, expected in zip(instruction_strings, expected_instructions))
 30 | 
 31 | 
 32 | def parse_offset(ldr_inst_offset_str: str) -> Optional[int]:
 33 |     """
 34 |     Parse the offset from the ldr instruction string.
 35 |     """
 36 |     try:
 37 |         parts = ldr_inst_offset_str.split("[")[1].split("]")[0].split(",")
 38 |         offset = int(parts[1].strip()[1:], 16)
 39 |         return offset
 40 |     except (IndexError, ValueError) as e:
 41 |         print(f"Error parsing offset: {e}")
 42 |         return None
 43 | 
 44 | 
 45 | def get_page_address(adrp_inst: Instruction) -> Optional[int]:
 46 |     """
 47 |     Get the page address from the adrp instruction.
 48 |     """
 49 |     try:
 50 |         page_address = int(adrp_inst.getFormattedArgument(1)[1:], 16)
 51 |         return page_address
 52 |     except ValueError as e:
 53 |         print(f"Error parsing page address: {e}")
 54 |         return None
 55 | 
 56 | 
 57 | def get_selector(doc: Document, address: int) -> Optional[str]:
 58 |     """
 59 |     Extract the Objective-C selector from a stub function.
 60 |     """
 61 |     seg = doc.getCurrentSegment()
 62 |     adrp_inst = seg.getInstructionAtAddress(address)
 63 |     ldr_inst = seg.getInstructionAtAddress(address + 4)
 64 | 
 65 |     if not adrp_inst or not ldr_inst:
 66 |         print(f"Error: Couldn't read instructions at 0x{address:X} for selector extraction")
 67 |         return None
 68 | 
 69 |     page = get_page_address(adrp_inst)
 70 |     offset = parse_offset(str(ldr_inst.getFormattedArgument(1)))
 71 | 
 72 |     if page is None or offset is None:
 73 |         return None
 74 | 
 75 |     selector_addr = page + offset
 76 |     selector_ptr = doc.readUInt64LE(selector_addr)
 77 |     if selector_ptr:
 78 |         return read_c_string(doc, selector_ptr)
 79 | 
 80 |     return None
 81 | 
 82 | 
 83 | def rename_objc_stubs() -> None:
 84 |     """
 85 |     Main function to rename Objective-C stub functions in the current document.
 86 |     """
 87 |     doc = Document.getCurrentDocument()
 88 |     seg = doc.getSegmentByName("__TEXT")
 89 |     if not seg:
 90 |         print("Error: __TEXT segment not found")
 91 |         return
 92 | 
 93 |     renamed_functions = 0
 94 |     for procedure_address in seg.getNamedAddresses():
 95 |         procedure_name = doc.getNameAtAddress(procedure_address)
 96 |         if not procedure_name.startswith("sub_"):
 97 |             continue
 98 | 
 99 |         try:
100 |             if not is_objc_stub(doc, procedure_address):
101 |                 continue
102 | 
103 |             selector = get_selector(doc, procedure_address)
104 |             if not selector:
105 |                 print(f"Error: Failed to extract selector from stub at 0x{procedure_address:X} ({procedure_name})")
106 |                 continue
107 |         except Exception as exc:
108 |             print(f"Failed to analyze function 0x{procedure_address:X} ({procedure_name}): {exc}")
109 |             continue
110 | 
111 |         renamed_functions += 1
112 |         doc.setNameAtAddress(procedure_address, selector)
113 | 
114 |     print(f"Renamed {renamed_functions} stubs")
115 | 
116 | 
117 | if __name__ == "__main__":
118 |     rename_objc_stubs()
119 | 


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