[llvm-dev] question about llvmlite

[Samaneh Berenjian via llvm-dev]

​Hi all,

I am using llvmlite for pyvex and I want the output of my code (which is written based on llvmlite) to be like pyvex. In pyvex, (https://github.com/angr/pyvex). Considering pyvex, I tried to implement the following statements in pyvex to llvmlite:

for stmt in irsb.statements:

   if isinstance(stmt, pyvex.IRStmt.Store):

      print "ST%s(%s) = %s" % (self.endness[-2:].lower(), self.addr, self.data) (which gets the data in a register and store it in another register)

I translate it in llvmlite as follows:

from ctypes import CFUNCTYPE, c_int

import archinfo

import llvmlite.ir as ll

import llvmlite.binding as llvm

import pyvex

CODE = b"\x55\x48\x8b\x05\xb8\x13\x00\x00"

mehran = -100

llvm.initialize()

llvm.initialize_native_target()

llvm.initialize_native_asmprinter()

module = ll.Module()

func_ty = ll.FunctionType(ll.VoidType(), [])

func = ll.Function(module, func_ty, name='read_instructions')

a = func.args

bb_entry = func.append_basic_block('entry')

irbuilder = ll.IRBuilder(bb_entry)

int_type = ll.IntType(64);

irsb = pyvex.block.IRSB(CODE, 0x400400, archinfo.ArchAMD64())

for stmt in irsb.statements:

    #if isinstance(pyvex.IRStmt.Store):

    with irbuilder.if_then(stmt, pyvex.IRStmt.Store):

       t = irbuilder.load_reg(ll.IntType(64), stmt.data)

       t1 = irbuilder.load_reg(ll.IntType(64), stmt.addr)

       tcall = irbuilder.call(func, [t])

       t1call = irbuilder.call(func, [t1])

       result  =  irbuilder.store_reg(ll.Constant(ll.IntType(64), t), ll.IntType(64), t1)

       irbuilder.ret( result )

       print( module )

       target = llvm.Target.from_default_triple()

       target_machine = target.create_target_machine()

       backing_mod = llvm.parse_assembly("")

       engine = llvm.create_mcjit_compiler(backing_mod, target_machine)

       mod = llvm.parse_assembly( str( module ) )

       mod.verify()

       engine.add_module(mod)

       engine.finalize_object()

       func_ptr = engine.get_function_address("read_instructions")

       c_fn_fib = CFUNCTYPE(c_int64, c_int64)(func_ptr)

           

Having the above code, when running it, I am stopped with error:

AttributeError: 'IMark' object has no attribute 'data'

Can anyone help me in this way?

Thank you

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[Brian Cain via llvm-dev]

I think you want “stmt.addr” and “stmt.data” instead of “self.addr”, “self.data”.

 

You can check what attributes an object has with “dir(self)” and “dir(stmt)”.  The error indicates you’ve referenced an attribute of “self” that doesn’t exist.

 

-Brian

[Samaneh Berenjian via llvm-dev]

Thank you for the reply. In the case of my code, it does not matter to use stmt or self. I even did your suggestion but right now it does not know the self. :(