src/llvm/bindings/python/llvm/disassembler.py

   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
  10 from ctypes import CFUNCTYPE
  11 from ctypes import POINTER
  12 from ctypes import addressof
  13 from ctypes import c_byte
  14 from ctypes import c_char_p
  15 from ctypes import c_int
  16 from ctypes import c_size_t
  17 from ctypes import c_ubyte
  18 from ctypes import c_uint64
  19 from ctypes import c_void_p
  20 from ctypes import cast
  21
  22 from .common import LLVMObject
  23 from .common import c_object_p
  24 from .common import get_library
  25
  26 __all__ = [
  27     'Disassembler',
  28 ]
  29
  30 lib = get_library()
  31 callbacks = {}
  32
  33 # Constants for set_options
  34 Option_UseMarkup = 1
  35
  36
  37
  38 _initialized = False
  39 _targets = ['AArch64', 'ARM', 'Hexagon', 'MSP430', 'Mips', 'NVPTX', 'PowerPC', 'R600', 'Sparc', 'SystemZ', 'X86', 'XCore']
  40 def _ensure_initialized():
  41     global _initialized
  42     if not _initialized:
  43         # Here one would want to call the functions
  44         # LLVMInitializeAll{TargetInfo,TargetMC,Disassembler}s, but
  45         # unfortunately they are only defined as static inline
  46         # functions in the header files of llvm-c, so they don't exist
  47         # as symbols in the shared library.
  48         # So until that is fixed use this hack to initialize them all
  49         for tgt in _targets:
  50             for initializer in ("TargetInfo", "TargetMC", "Disassembler"):
  51                 try:
  52                     f = getattr(lib, "LLVMInitialize" + tgt + initializer)
  53                 except AttributeError:
  54                     continue
  55                 f()
  56         _initialized = True
  57
  58
  59 class Disassembler(LLVMObject):
  60     """Represents a disassembler instance.
  61
  62     Disassembler instances are tied to specific "triple," which must be defined
  63     at creation time.
  64
  65     Disassembler instances can disassemble instructions from multiple sources.
  66     """
  67     def __init__(self, triple):
  68         """Create a new disassembler instance.
  69
  70         The triple argument is the triple to create the disassembler for. This
  71         is something like 'i386-apple-darwin9'.
  72         """
  73
  74         _ensure_initialized()
  75
  76         ptr = lib.LLVMCreateDisasm(c_char_p(triple), c_void_p(None), c_int(0),
  77                 callbacks['op_info'](0), callbacks['symbol_lookup'](0))
  78         if not ptr:
  79             raise Exception('Could not obtain disassembler for triple: %s' %
  80                             triple)
  81
  82         LLVMObject.__init__(self, ptr, disposer=lib.LLVMDisasmDispose)
  83
  84     def get_instruction(self, source, pc=0):
  85         """Obtain the next instruction from an input source.
  86
  87         The input source should be a str or bytearray or something that
  88         represents a sequence of bytes.
  89
  90         This function will start reading bytes from the beginning of the
  91         source.
  92
  93         The pc argument specifies the address that the first byte is at.
  94
  95         This returns a 2-tuple of:
  96
  97           long number of bytes read. 0 if no instruction was read.
  98           str representation of instruction. This will be the assembly that
  99             represents the instruction.
 100         """
 101         buf = cast(c_char_p(source), POINTER(c_ubyte))
 102         out_str = cast((c_byte * 255)(), c_char_p)
 103
 104         result = lib.LLVMDisasmInstruction(self, buf, c_uint64(len(source)),
 105                                            c_uint64(pc), out_str, 255)
 106
 107         return (result, out_str.value)
 108
 109     def get_instructions(self, source, pc=0):
 110         """Obtain multiple instructions from an input source.
 111
 112         This is like get_instruction() except it is a generator for all
 113         instructions within the source. It starts at the beginning of the
 114         source and reads instructions until no more can be read.
 115
 116         This generator returns 3-tuple of:
 117
 118           long address of instruction.
 119           long size of instruction, in bytes.
 120           str representation of instruction.
 121         """
 122         source_bytes = c_char_p(source)
 123         out_str = cast((c_byte * 255)(), c_char_p)
 124
 125         # This could probably be written cleaner. But, it does work.
 126         buf = cast(source_bytes, POINTER(c_ubyte * len(source))).contents
 127         offset = 0
 128         address = pc
 129         end_address = pc + len(source)
 130         while address < end_address:
 131             b = cast(addressof(buf) + offset, POINTER(c_ubyte))
 132             result = lib.LLVMDisasmInstruction(self, b,
 133                     c_uint64(len(source) - offset), c_uint64(address),
 134                     out_str, 255)
 135
 136             if result == 0:
 137                 break
 138
 139             yield (address, result, out_str.value)
 140
 141             address += result
 142             offset += result
 143
 144     def set_options(self, options):
 145         if not lib.LLVMSetDisasmOptions(self, options):
 146             raise Exception('Unable to set all disassembler options in %i' % options)
 147
 148
 149 def register_library(library):
 150     library.LLVMCreateDisasm.argtypes = [c_char_p, c_void_p, c_int,
 151         callbacks['op_info'], callbacks['symbol_lookup']]
 152     library.LLVMCreateDisasm.restype = c_object_p
 153
 154     library.LLVMDisasmDispose.argtypes = [Disassembler]
 155
 156     library.LLVMDisasmInstruction.argtypes = [Disassembler, POINTER(c_ubyte),
 157             c_uint64, c_uint64, c_char_p, c_size_t]
 158     library.LLVMDisasmInstruction.restype = c_size_t
 159
 160     library.LLVMSetDisasmOptions.argtypes = [Disassembler, c_uint64]
 161     library.LLVMSetDisasmOptions.restype = c_int
 162
 163
 164 callbacks['op_info'] = CFUNCTYPE(c_int, c_void_p, c_uint64, c_uint64, c_uint64,
 165                                  c_int, c_void_p)
 166 callbacks['symbol_lookup'] = CFUNCTYPE(c_char_p, c_void_p, c_uint64,
 167                                        POINTER(c_uint64), c_uint64,
 168                                        POINTER(c_char_p))
 169
 170 register_library(lib)