1#===- disassembler.py - Python LLVM Bindings -----------------*- python -*--===# 2# 3# The LLVM Compiler Infrastructure 4# 5# This file is distributed under the University of Illinois Open Source 6# License. See LICENSE.TXT for details. 7# 8#===------------------------------------------------------------------------===# 9 10from ctypes import CFUNCTYPE 11from ctypes import POINTER 12from ctypes import addressof 13from ctypes import byref 14from ctypes import c_byte 15from ctypes import c_char_p 16from ctypes import c_int 17from ctypes import c_size_t 18from ctypes import c_ubyte 19from ctypes import c_uint64 20from ctypes import c_void_p 21from ctypes import cast 22 23from .common import LLVMObject 24from .common import c_object_p 25from .common import get_library 26 27__all__ = [ 28 'Disassembler', 29] 30 31lib = get_library() 32callbacks = {} 33 34class Disassembler(LLVMObject): 35 """Represents a disassembler instance. 36 37 Disassembler instances are tied to specific "triple," which must be defined 38 at creation time. 39 40 Disassembler instances can disassemble instructions from multiple sources. 41 """ 42 def __init__(self, triple): 43 """Create a new disassembler instance. 44 45 The triple argument is the triple to create the disassembler for. This 46 is something like 'i386-apple-darwin9'. 47 """ 48 ptr = lib.LLVMCreateDisasm(c_char_p(triple), c_void_p(None), c_int(0), 49 callbacks['op_info'](0), callbacks['symbol_lookup'](0)) 50 if not ptr.contents: 51 raise Exception('Could not obtain disassembler for triple: %s' % 52 triple) 53 54 LLVMObject.__init__(self, ptr, disposer=lib.LLVMDisasmDispose) 55 56 def get_instruction(self, source, pc=0): 57 """Obtain the next instruction from an input source. 58 59 The input source should be a str or bytearray or something that 60 represents a sequence of bytes. 61 62 This function will start reading bytes from the beginning of the 63 source. 64 65 The pc argument specifies the address that the first byte is at. 66 67 This returns a 2-tuple of: 68 69 long number of bytes read. 0 if no instruction was read. 70 str representation of instruction. This will be the assembly that 71 represents the instruction. 72 """ 73 buf = cast(c_char_p(source), POINTER(c_ubyte)) 74 out_str = cast((c_byte * 255)(), c_char_p) 75 76 result = lib.LLVMDisasmInstruction(self, buf, c_uint64(len(source)), 77 c_uint64(pc), out_str, 255) 78 79 return (result, out_str.value) 80 81 def get_instructions(self, source, pc=0): 82 """Obtain multiple instructions from an input source. 83 84 This is like get_instruction() except it is a generator for all 85 instructions within the source. It starts at the beginning of the 86 source and reads instructions until no more can be read. 87 88 This generator returns 3-tuple of: 89 90 long address of instruction. 91 long size of instruction, in bytes. 92 str representation of instruction. 93 """ 94 source_bytes = c_char_p(source) 95 out_str = cast((c_byte * 255)(), c_char_p) 96 97 # This could probably be written cleaner. But, it does work. 98 buf = cast(source_bytes, POINTER(c_ubyte * len(source))).contents 99 offset = 0 100 address = pc 101 end_address = pc + len(source) 102 while address < end_address: 103 b = cast(addressof(buf) + offset, POINTER(c_ubyte)) 104 result = lib.LLVMDisasmInstruction(self, b, 105 c_uint64(len(source) - offset), c_uint64(address), 106 out_str, 255) 107 108 if result == 0: 109 break 110 111 yield (address, result, out_str.value) 112 113 address += result 114 offset += result 115 116 117def register_library(library): 118 library.LLVMCreateDisasm.argtypes = [c_char_p, c_void_p, c_int, 119 callbacks['op_info'], callbacks['symbol_lookup']] 120 library.LLVMCreateDisasm.restype = c_object_p 121 122 library.LLVMDisasmDispose.argtypes = [Disassembler] 123 124 library.LLVMDisasmInstruction.argtypes = [Disassembler, POINTER(c_ubyte), 125 c_uint64, c_uint64, c_char_p, c_size_t] 126 library.LLVMDisasmInstruction.restype = c_size_t 127 128callbacks['op_info'] = CFUNCTYPE(c_int, c_void_p, c_uint64, c_uint64, c_uint64, 129 c_int, c_void_p) 130callbacks['symbol_lookup'] = CFUNCTYPE(c_char_p, c_void_p, c_uint64, 131 POINTER(c_uint64), c_uint64, 132 POINTER(c_char_p)) 133 134register_library(lib) 135