Instruction:
How would you explain what the following Python 3 function does
def execute(self, state, successors=None, arguments=None, ret_to=None):
        # fill out all the fun stuff we don't want to frontload
        if self.addr is None and not state.regs.ip.symbolic:
            self.addr = state.addr
        if self.arch is None:
            self.arch = state.arch
        if self.project is None:
            self.project = state.project
        if self.cc is None:
            if self.arch.name in DEFAULT_CC:
                self.cc = DEFAULT_CC[self.arch.name](self.arch)
            else:
                raise SimProcedureError('There is no default calling convention for architecture %s.'
                                        ' You must specify a calling convention.' % self.arch.name)

        inst = copy.copy(self)
        inst.state = state
        inst.successors = successors
        inst.ret_to = ret_to
        inst.inhibit_autoret = False

        # check to see if this is a syscall and if we should override its return value
        override = None
        if inst.is_syscall:
            state.history.recent_syscall_count = 1
            if len(state.posix.queued_syscall_returns):
                override = state.posix.queued_syscall_returns.pop(0)

        if callable(override):
            try:
                r = override(state, run=inst)
            except TypeError:
                r = override(state)
            inst.use_state_arguments = True

        elif override is not None:
            r = override
            inst.use_state_arguments = True

        else:
            # get the arguments

            # If the simprocedure is related to a Java function call the appropriate setup_args methos
            # TODO: should we move this?
            if self.is_java:
                sim_args = self._setup_args(inst, state, arguments)
                self.use_state_arguments = False

            # handle if this is a continuation from a return
            elif inst.is_continuation:
                if state.callstack.top.procedure_data is None:
                    raise SimProcedureError("Tried to return to a SimProcedure in an inapplicable stack frame!")

                saved_sp, sim_args, saved_local_vars, saved_lr = state.callstack.top.procedure_data
                state.regs.sp = saved_sp
                if saved_lr is not None:
                    state.regs.lr = saved_lr
                inst.arguments = sim_args
                inst.use_state_arguments = True
                inst.call_ret_expr = state.registers.load(state.arch.ret_offset, state.arch.bytes, endness=state.arch.register_endness)
                for name, val in saved_local_vars:
                    setattr(inst, name, val)
            else:
                if arguments is None:
                    inst.use_state_arguments = True
                    sim_args = [ inst.arg(_) for _ in range(inst.num_args) ]
                    inst.arguments = sim_args
                else:
                    inst.use_state_arguments = False
                    sim_args = arguments[:inst.num_args]
                    inst.arguments = arguments

            # run it
            l.debug("Executing %s%s%s%s%s with %s, %s", *(inst._describe_me() + (sim_args, inst.kwargs)))
            r = getattr(inst, inst.run_func)(*sim_args, **inst.kwargs)

        if inst.returns and inst.is_function and not inst.inhibit_autoret:
            inst.ret(r)

        return inst

Response:
Call this method with a SimState and a SimSuccessors to execute the procedure.

        Alternately, successors may be none if this is an inline call. In that case, you should
        provide arguments to the function.


Instruction:
Write a Python 3 script for
returning the ith argument. Raise a SimProcedureArgumentError if we don t have such an argument available.

Response:
def arg(self, i):
        """
        Returns the ith argument. Raise a SimProcedureArgumentError if we don't have such an argument available.

        :param int i: The index of the argument to get
        :return: The argument
        :rtype: object
        """
        if self.use_state_arguments:
            r = self.cc.arg(self.state, i)
        else:
            if i >= len(self.arguments):
                raise SimProcedureArgumentError("Argument %d does not exist." % i)
            r = self.arguments[i]           # pylint: disable=unsubscriptable-object

        l.debug("returning argument")
        return r


Instruction:
Given the following Python 3 function, write the documentation
def inline_call(self, procedure, *arguments, **kwargs):
        e_args = [ self.state.solver.BVV(a, self.state.arch.bits) if isinstance(a, int) else a for a in arguments ]
        p = procedure(project=self.project, **kwargs)
        return p.execute(self.state, None, arguments=e_args)

Response: In - line call another SimProcedure in - line to retrieve its return value.


Instruction:
How would you implement a function in Python 3 that
adds an exit representing a return from this function.

Response:
def ret(self, expr=None):
        """
        Add an exit representing a return from this function.
        If this is not an inline call, grab a return address from the state and jump to it.
        If this is not an inline call, set a return expression with the calling convention.
        """
        self.inhibit_autoret = True

        if expr is not None:
            if o.SIMPLIFY_RETS in self.state.options:
                l.debug("... simplifying")
                l.debug("... before: %s", expr)
                expr = self.state.solver.simplify(expr)
                l.debug("... after: %s", expr)

            if self.symbolic_return:
                size = len(expr)
                new_expr = self.state.solver.Unconstrained(
                        "symbolic_return_" + self.display_name,
                        size,
                        key=('symbolic_return', self.display_name)) #pylint:disable=maybe-no-member
                self.state.add_constraints(new_expr == expr)
                expr = new_expr

            self.ret_expr = expr

        ret_addr = None
        # TODO: I had to put this check here because I don't understand why self.use_state_arguments gets reset to true
        # when calling the function ret. at the calling point the attribute is set to False
        if isinstance(self.addr, SootAddressDescriptor):
            ret_addr = self._compute_ret_addr(expr)
        elif self.use_state_arguments:
            ret_addr = self.cc.teardown_callsite(
                    self.state,
                    expr,
                    arg_types=[False]*self.num_args if self.cc.args is None else None)

        if not self.should_add_successors:
            l.debug("Returning without setting exits due to 'internal' call.")
            return

        if self.ret_to is not None:
            ret_addr = self.ret_to

        if ret_addr is None:
            raise SimProcedureError("No source for return address in ret() call!")

        self._prepare_ret_state()

        self._exit_action(self.state, ret_addr)
        self.successors.add_successor(self.state, ret_addr, self.state.solver.true, 'Ijk_Ret')


Instruction:
Can you create a Python 3 function that
adds an exit representing calling another function via pointer.

Response:
def call(self, addr, args, continue_at, cc=None):
        """
        Add an exit representing calling another function via pointer.

        :param addr:        The address of the function to call
        :param args:        The list of arguments to call the function with
        :param continue_at: Later, when the called function returns, execution of the current
                            procedure will continue in the named method.
        :param cc:          Optional: use this calling convention for calling the new function.
                            Default is to use the current convention.
        """
        self.inhibit_autoret = True

        if cc is None:
            cc = self.cc

        call_state = self.state.copy()
        ret_addr = self.make_continuation(continue_at)
        saved_local_vars = list(zip(self.local_vars, map(lambda name: getattr(self, name), self.local_vars)))
        simcallstack_entry = (self.state.regs.sp if hasattr(self.state.regs, "sp") else None,
                              self.arguments,
                              saved_local_vars,
                              self.state.regs.lr if self.state.arch.lr_offset is not None else None)
        cc.setup_callsite(call_state, ret_addr, args)
        call_state.callstack.top.procedure_data = simcallstack_entry

        # TODO: Move this to setup_callsite?
        if isinstance(call_state.addr, SootAddressDescriptor):
            pass
        elif call_state.libc.ppc64_abiv == 'ppc64_1':
            call_state.regs.r2 = self.state.mem[addr + 8:].long.resolved
            addr = call_state.mem[addr:].long.resolved
        elif call_state.arch.name in ('MIPS32', 'MIPS64'):
            call_state.regs.t9 = addr

        self._exit_action(call_state, addr)
        self.successors.add_successor(call_state, addr, call_state.solver.true, 'Ijk_Call')

        if o.DO_RET_EMULATION in self.state.options:
            # we need to set up the call because the continuation will try to tear it down
            ret_state = self.state.copy()
            cc.setup_callsite(ret_state, ret_addr, args)
            ret_state.callstack.top.procedure_data = simcallstack_entry
            guard = ret_state.solver.true if o.TRUE_RET_EMULATION_GUARD in ret_state.options else ret_state.solver.false
            self.successors.add_successor(ret_state, ret_addr, guard, 'Ijk_FakeRet')


Instruction:
How would you explain what the following Python 3 function does
def jump(self, addr):
        self.inhibit_autoret = True
        self._exit_action(self.state, addr)
        self.successors.add_successor(self.state, addr, self.state.solver.true, 'Ijk_Boring')

Response: Add an exit representing jumping to an address.


Instruction:
How would you explain what the following Python 3 function does
def exit(self, exit_code):
        self.inhibit_autoret = True
        self.state.options.discard(o.AST_DEPS)
        self.state.options.discard(o.AUTO_REFS)

        if isinstance(exit_code, int):
            exit_code = self.state.solver.BVV(exit_code, self.state.arch.bits)
        self.state.history.add_event('terminate', exit_code=exit_code)
        self.successors.add_successor(self.state, self.state.regs.ip, self.state.solver.true, 'Ijk_Exit')

Response: Add an exit representing terminating the program.


Instruction:
Given the following Python 3 function, write the documentation
def _explore(self):

        # TODO: The worklist algorithm can definitely use some optimizations. It is a future work.

        # The worklist holds individual VFGNodes that comes from the VFG
        # Initialize the worklist with all nodes in VFG
        worklist = list(self._vfg.graph.nodes())
        # Set up a set of worklist for fast inclusion test
        worklist_set = set(worklist)

        # A dict storing defs set
        # variable -> locations
        live_defs_per_node = { }

        while worklist:
            # Pop out a node
            node = worklist[0]
            worklist_set.remove(node)
            worklist = worklist[ 1 : ]

            # Grab all final states. There are usually more than one (one state for each successor), and we gotta
            # process all of them
            final_states = node.final_states

            if node in live_defs_per_node:
                live_defs = live_defs_per_node[node]
            else:
                live_defs = { }
                live_defs_per_node[node] = live_defs

            successing_nodes = self._vfg.graph.successors(node)
            for state in final_states:
                if state.history.jumpkind == 'Ijk_FakeRet' and len(final_states) > 1:
                    # Skip fakerets if there are other control flow transitions available
                    continue

                # TODO: Match the jumpkind
                # TODO: Support cases where IP is undecidable
                corresponding_successors = [ n for n in successing_nodes if n.addr == state.solver.eval(state.ip) ]
                if not corresponding_successors:
                    continue
                successing_node = corresponding_successors[0]

                new_defs = self._track(state, live_defs)

                if successing_node in live_defs_per_node:
                    defs_for_next_node = live_defs_per_node[successing_node]
                else:
                    defs_for_next_node = { }
                    live_defs_per_node[successing_node] = defs_for_next_node

                changed = False
                for var, code_loc_set in new_defs.items():
                    if var not in defs_for_next_node:
                        defs_for_next_node[var] = code_loc_set
                        changed = True

                    else:
                        for code_loc in code_loc_set:
                            if code_loc not in defs_for_next_node[var]:
                                defs_for_next_node[var].add(code_loc)
                                changed = True

                if changed:
                    # Put all reachable successors back to our worklist again
                    if successing_node not in worklist_set:
                        worklist.append(successing_node)
                        worklist_set.add(successing_node)
                    all_successors_dict = networkx.dfs_successors(self._vfg.graph, source=successing_node)
                    for successors in all_successors_dict.values():
                        for s in successors:
                            if s not in worklist_set:
                                worklist.append(s)
                                worklist_set.add(s)

Response: Explore the entire VFG and generate def - use chains for all registers and memory addresses using a worklist.


Instruction:
Create a Python 3 function to
give all live definitions prior to this program point, track the changes, and return a new list of live definitions. We scan through the action list of the new state to track the changes. :param state: The input state at that program point. :param live_defs: A list of all live definitions prior to reaching this program point. :returns: A list of new live definitions.

Response:
def _track(self, state, live_defs):
        """
        Given all live definitions prior to this program point, track the changes, and return a new list of live
        definitions. We scan through the action list of the new state to track the changes.

        :param state:       The input state at that program point.
        :param live_defs:   A list of all live definitions prior to reaching this program point.
        :returns:           A list of new live definitions.
        """

        # Make a copy of live_defs
        live_defs = live_defs.copy()

        action_list = list(state.history.recent_actions)

        # Since all temporary variables are local, we simply track them in a local dict
        temps = { }

        # All dependence edges are added to the graph either at the end of this method, or when they are going to be
        # overwritten by a new edge. This is because we sometimes have to modify a  previous edge (e.g. add new labels
        # to the edge)
        temps_to_edges = defaultdict(list)
        regs_to_edges = defaultdict(list)

        def _annotate_edges_in_dict(dict_, key, **new_labels):
            """

            :param dict_:       The dict, can be either `temps_to_edges` or `regs_to_edges`
            :param key:         The key used in finding elements in the dict
            :param new_labels:  New labels to be added to those edges
            """

            for edge_tuple in dict_[key]:
                # unpack it
                _, _, labels = edge_tuple
                for k, v in new_labels.items():
                    if k in labels:
                        labels[k] = labels[k] + (v, )
                    else:
                        # Construct a tuple
                        labels[k] = (v, )

        def _dump_edge_from_dict(dict_, key, del_key=True):
            """
            Pick an edge from the dict based on the key specified, add it to our graph, and remove the key from dict.

            :param dict_:   The dict, can be either `temps_to_edges` or `regs_to_edges`.
            :param key:     The key used in finding elements in the dict.
            """
            for edge_tuple in dict_[key]:
                # unpack it
                prev_code_loc, current_code_loc, labels = edge_tuple
                # Add the new edge
                self._add_edge(prev_code_loc, current_code_loc, **labels)

            # Clear it
            if del_key:
                del dict_[key]

        for a in action_list:

            if a.bbl_addr is None:
                current_code_loc = CodeLocation(None, None, sim_procedure=a.sim_procedure)
            else:
                current_code_loc = CodeLocation(a.bbl_addr, a.stmt_idx, ins_addr=a.ins_addr)

            if a.type == "mem":
                if a.actual_addrs is None:
                    # For now, mem reads don't necessarily have actual_addrs set properly
                    addr_list = set(state.memory.normalize_address(a.addr.ast, convert_to_valueset=True))
                else:
                    addr_list = set(a.actual_addrs)

                for addr in addr_list:
                    variable = SimMemoryVariable(addr, a.data.ast.size()) # TODO: Properly unpack the SAO

                    if a.action == "read":
                        # Create an edge between def site and use site

                        prevdefs = self._def_lookup(live_defs, variable)

                        for prev_code_loc, labels in prevdefs.items():
                            self._read_edge = True
                            self._add_edge(prev_code_loc, current_code_loc, **labels)

                    else: #if a.action == "write":
                        # Kill the existing live def
                        self._kill(live_defs, variable, current_code_loc)

                    # For each of its register dependency and data dependency, we revise the corresponding edge
                    for reg_off in a.addr.reg_deps:
                        _annotate_edges_in_dict(regs_to_edges, reg_off, subtype='mem_addr')
                    for tmp in a.addr.tmp_deps:
                        _annotate_edges_in_dict(temps_to_edges, tmp, subtype='mem_addr')

                    for reg_off in a.data.reg_deps:
                        _annotate_edges_in_dict(regs_to_edges, reg_off, subtype='mem_data')
                    for tmp in a.data.tmp_deps:
                        _annotate_edges_in_dict(temps_to_edges, tmp, subtype='mem_data')

            elif a.type == 'reg':
                # For now, we assume a.offset is not symbolic
                # TODO: Support symbolic register offsets

                #variable = SimRegisterVariable(a.offset, a.data.ast.size())
                variable = SimRegisterVariable(a.offset, self.project.arch.bits)

                if a.action == 'read':
                    # What do we want to do?
                    prevdefs = self._def_lookup(live_defs, variable)

                    if a.offset in regs_to_edges:
                        _dump_edge_from_dict(regs_to_edges, a.offset)

                    for prev_code_loc, labels in prevdefs.items():
                        edge_tuple = (prev_code_loc, current_code_loc, labels)
                        regs_to_edges[a.offset].append(edge_tuple)

                else:
                    # write
                    self._kill(live_defs, variable, current_code_loc)

            elif a.type == 'tmp':
                # tmp is definitely not symbolic
                if a.action == 'read':
                    prev_code_loc = temps[a.tmp]
                    edge_tuple = (prev_code_loc, current_code_loc, {'type':'tmp', 'data':a.tmp})

                    if a.tmp in temps_to_edges:
                        _dump_edge_from_dict(temps_to_edges, a.tmp)

                    temps_to_edges[a.tmp].append(edge_tuple)

                else:
                    # write
                    temps[a.tmp] = current_code_loc

            elif a.type == 'exit':
                # exits should only depend on tmps

                for tmp in a.tmp_deps:
                    prev_code_loc = temps[tmp]
                    edge_tuple = (prev_code_loc, current_code_loc, {'type': 'exit', 'data': tmp})

                    if tmp in temps_to_edges:
                        _dump_edge_from_dict(temps_to_edges, tmp)

                    temps_to_edges[tmp].append(edge_tuple)

        # In the end, dump all other edges in those two dicts
        for reg_offset in regs_to_edges:
            _dump_edge_from_dict(regs_to_edges, reg_offset, del_key=False)
        for tmp in temps_to_edges:
            _dump_edge_from_dict(temps_to_edges, tmp, del_key=False)

        return live_defs


Instruction:
Can you generate a brief explanation for the following Python 3 code
def _def_lookup(self, live_defs, variable):

        prevdefs = { }

        if variable in live_defs:
            code_loc_set = live_defs[variable]
            for code_loc in code_loc_set:
                # Label edges with cardinality or actual sets of addresses
                if isinstance(variable, SimMemoryVariable):
                    type_ = 'mem'
                elif isinstance(variable, SimRegisterVariable):
                    type_ = 'reg'
                else:
                    raise AngrDDGError('Unknown variable type %s' % type(variable))

                if self.keep_data is True:
                    data = variable

                    prevdefs[code_loc] = {
                        'type': type_,
                        'data': data
                    }

                else:
                    if code_loc in prevdefs:
                        count = prevdefs[code_loc]['count'] + 1
                    else:
                        count = 0
                    prevdefs[code_loc] = {
                        'type': type_,
                        'count': count
                    }
        return prevdefs

Response: This is a backward lookup in the previous defs.


Instruction:
Can you generate a brief explanation for the following Python 3 code
def _kill(self, live_defs, variable, code_loc):

        # Case 1: address perfectly match, we kill
        # Case 2: a is a subset of the original address
        # Case 3: a is a superset of the original address

        live_defs[variable] = { code_loc }
        l.debug("XX CodeLoc %s kills variable %s", code_loc, variable)

Response: Kill previous defs. `addr_list` is a list of normalized addresses.


Instruction:
Create a Python 3 function to
add an edge from s_a to s_b.

Response:
def _add_edge(self, s_a, s_b, **edge_labels):
        """
        Add an edge in the graph from `s_a` to statement `s_b`, where `s_a` and `s_b` are tuples of statements of the
        form (irsb_addr, stmt_idx).
        """
        # Is that edge already in the graph ?
        # If at least one is new, then we are not redoing the same path again
        if (s_a, s_b) not in self.graph.edges():
            self.graph.add_edge(s_a, s_b, **edge_labels)
            self._new = True
            l.info("New edge: %s --> %s", s_a, s_b)


Instruction:
Create a Python 3 function to
get all nodes matching the given basic block address and statement index.

Response:
def get_all_nodes(self, simrun_addr, stmt_idx):
        """
        Get all DDG nodes matching the given basic block address and statement index.
        """
        nodes=[]
        for n in self.graph.nodes():
            if n.simrun_addr == simrun_addr and n.stmt_idx == stmt_idx:
                nodes.add(n)
        return nodes


Instruction:
Here you have a function in Python 3, explain what it does
def vector_args(self, args):
        for i in reversed(range(self._vector_count)):
            pieces = []
            for vec in args:
                pieces.append(vec[(i+1) * self._vector_size - 1 : i * self._vector_size])
            yield pieces

Response: Yields each individual lane pair from the arguments in the order from most significan to least significant


Instruction:
Write a Python 3 function for
counting the leading zeroes

Response:
def _op_generic_Clz(self, args):
        """Count the leading zeroes"""
        wtf_expr = claripy.BVV(self._from_size, self._from_size)
        for a in range(self._from_size):
            bit = claripy.Extract(a, a, args[0])
            wtf_expr = claripy.If(bit==1, claripy.BVV(self._from_size-a-1, self._from_size), wtf_expr)
        return wtf_expr


Instruction:
Can you generate the documentation for the following Python 3 function
def _op_generic_Ctz(self, args):
        wtf_expr = claripy.BVV(self._from_size, self._from_size)
        for a in reversed(range(self._from_size)):
            bit = claripy.Extract(a, a, args[0])
            wtf_expr = claripy.If(bit == 1, claripy.BVV(a, self._from_size), wtf_expr)
        return wtf_expr

Response: Count the trailing zeroes in the ctz table


Instruction:
Given the following Python 3 function, write the documentation
def _op_generic_HAdd(self, args):
        components = []
        for a, b in self.vector_args(args):
            if self.is_signed:
                a = a.sign_extend(self._vector_size)
                b = b.sign_extend(self._vector_size)
            else:
                a = a.zero_extend(self._vector_size)
                b = b.zero_extend(self._vector_size)
            components.append((a + b)[self._vector_size:1])
        return claripy.Concat(*components)

Response: Halving add for some ARM NEON instructions.


Instruction:
Write a Python 3 script to
return unsigned saturated BV from signed BV.

Response:
def _op_generic_StoU_saturation(self, value, min_value, max_value): #pylint:disable=no-self-use
        """
        Return unsigned saturated BV from signed BV.
        Min and max value should be unsigned.
        """
        return claripy.If(
            claripy.SGT(value, max_value),
            max_value,
            claripy.If(claripy.SLT(value, min_value), min_value, value))


Instruction:
Make a summary of the following Python 3 code
def _scan_block(self, cfg_job):

        addr = cfg_job.addr
        current_func_addr = cfg_job.func_addr

        if self._addr_hooked_or_syscall(addr):
            entries = self._scan_procedure(cfg_job, current_func_addr)

        else:
            entries = self._scan_soot_block(cfg_job, current_func_addr)

        return entries

Response: Scan a basic block starting at a specific address.


Instruction:
Write a Python 3 script for
scanning the Soot block for successors and create a list of entries.

Response:
def _scan_soot_block(self, cfg_job, current_func_addr):
        """
        Generate a list of successors (generating them each as entries) to IRSB.
        Updates previous CFG nodes with edges.

        :param CFGJob cfg_job: The CFGJob instance.
        :param int current_func_addr: Address of the current function
        :return: a list of successors
        :rtype: list
        """

        addr, function_addr, cfg_node, soot_block = self._generate_cfgnode(cfg_job, current_func_addr)

        # Add edges going to this node in function graphs
        cfg_job.apply_function_edges(self, clear=True)

        # function_addr and current_function_addr can be different. e.g. when tracing an optimized tail-call that jumps
        # into another function that has been identified before.

        if cfg_node is None:
            # exceptions occurred, or we cannot get a CFGNode for other reasons
            return [ ]

        self._graph_add_edge(cfg_node, cfg_job.src_node, cfg_job.jumpkind, cfg_job.src_ins_addr,
                             cfg_job.src_stmt_idx
                             )
        self._function_add_node(cfg_node, function_addr)

        # If we have traced it before, don't trace it anymore
        if addr in self._traced_addresses:
            # the address has been traced before
            return [ ]
        else:
            # Mark the address as traced
            self._traced_addresses.add(addr)

        # soot_block is only used once per CFGNode. We should be able to clean up the CFGNode here in order to save memory
        cfg_node.soot_block = None

        successors = self._soot_get_successors(addr, current_func_addr, soot_block, cfg_node)

        entries = [ ]

        for suc in successors:
            stmt_idx, stmt_addr, target, jumpkind = suc

            entries += self._create_jobs(target, jumpkind, function_addr, soot_block, addr, cfg_node, stmt_addr,
                                         stmt_idx
                                         )

        return entries


Instruction:
Write a Python 3 function for
creating a list of CFGJobs that are needed to perform a function call or exit.

Response:
def _create_jobs(self, target, jumpkind, current_function_addr, soot_block, addr, cfg_node, stmt_addr, stmt_idx):  # pylint:disable=arguments-differ

        """
        Given a node and details of a successor, makes a list of CFGJobs
        and if it is a call or exit marks it appropriately so in the CFG

        :param int target:          Destination of the resultant job
        :param str jumpkind:        The jumpkind of the edge going to this node
        :param int current_function_addr: Address of the current function
        :param pyvex.IRSB irsb:     IRSB of the predecessor node
        :param int addr:            The predecessor address
        :param CFGNode cfg_node:    The CFGNode of the predecessor node
        :param int ins_addr:        Address of the source instruction.
        :param int stmt_addr:       ID of the source statement.
        :return:                    a list of CFGJobs
        :rtype:                     list
        """

        target_addr = target

        jobs = [ ]

        if target_addr is None:
            # The target address is not a concrete value

            if jumpkind == "Ijk_Ret":
                # This block ends with a return instruction.
                if current_function_addr != -1:
                    self._function_exits[current_function_addr].add(addr)
                    self._function_add_return_site(addr, current_function_addr)
                    self.functions[current_function_addr].returning = True
                    self._pending_jobs.add_returning_function(current_function_addr)

                cfg_node.has_return = True

        elif target_addr is not None:
            # This is a direct jump with a concrete target.

            # pylint: disable=too-many-nested-blocks
            if jumpkind in ('Ijk_Boring', 'Ijk_InvalICache'):
                # it might be a jumpout
                target_func_addr = None
                if target_addr in self._traced_addresses:
                    node = self.get_any_node(target_addr)
                    if node is not None:
                        target_func_addr = node.function_address
                if target_func_addr is None:
                    target_func_addr = current_function_addr

                to_outside = not target_func_addr == current_function_addr

                edge = FunctionTransitionEdge(cfg_node, target_addr, current_function_addr,
                                              to_outside=to_outside,
                                              dst_func_addr=target_func_addr,
                                              ins_addr=stmt_addr,
                                              stmt_idx=stmt_idx,
                                              )

                ce = CFGJob(target_addr, target_func_addr, jumpkind, last_addr=addr, src_node=cfg_node,
                            src_ins_addr=stmt_addr, src_stmt_idx=stmt_idx, func_edges=[ edge ])
                jobs.append(ce)

            elif jumpkind == 'Ijk_Call' or jumpkind.startswith("Ijk_Sys"):
                jobs += self._create_job_call(addr, soot_block, cfg_node, stmt_idx, stmt_addr, current_function_addr,
                                              target_addr, jumpkind, is_syscall=False
                                              )
                self._pending_jobs.add_returning_function(target.method)

            else:
                # TODO: Support more jumpkinds
                l.debug("Unsupported jumpkind %s", jumpkind)

        return jobs


Instruction:
Implement a function in Python 3 to
revisit the entire control flow graph and create Function instances accordingly.

Response:
def make_functions(self):
        """
        Revisit the entire control flow graph, create Function instances accordingly, and correctly put blocks into
        each function.

        Although Function objects are crated during the CFG recovery, they are neither sound nor accurate. With a
        pre-constructed CFG, this method rebuilds all functions bearing the following rules:

            - A block may only belong to one function.
            - Small functions lying inside the startpoint and the endpoint of another function will be merged with the
              other function
            - Tail call optimizations are detected.
            - PLT stubs are aligned by 16.

        :return: None
        """

        tmp_functions = self.kb.functions.copy()

        for function in tmp_functions.values():
            function.mark_nonreturning_calls_endpoints()

        # Clear old functions dict
        self.kb.functions.clear()

        blockaddr_to_function = { }
        traversed_cfg_nodes = set()

        function_nodes = set()

        # Find nodes for beginnings of all functions
        for _, dst, data in self.graph.edges(data=True):
            jumpkind = data.get('jumpkind', "")
            if jumpkind == 'Ijk_Call' or jumpkind.startswith('Ijk_Sys'):
                function_nodes.add(dst)

        entry_node = self.get_any_node(self._binary.entry)
        if entry_node is not None:
            function_nodes.add(entry_node)

        for n in self.graph.nodes():
            funcloc = self._loc_to_funcloc(n.addr)
            if funcloc in tmp_functions:
                function_nodes.add(n)

        # traverse the graph starting from each node, not following call edges
        # it's important that we traverse all functions in order so that we have a greater chance to come across
        # rational functions before its irrational counterparts (e.g. due to failed jump table resolution)

        min_stage_2_progress = 50.0
        max_stage_2_progress = 90.0
        nodes_count = len(function_nodes)
        for i, fn in enumerate(function_nodes):

            if self._show_progressbar or self._progress_callback:
                progress = min_stage_2_progress + (max_stage_2_progress - min_stage_2_progress) * (i * 1.0 / nodes_count)
                self._update_progress(progress)

            self._graph_bfs_custom(self.graph, [ fn ], self._graph_traversal_handler, blockaddr_to_function,
                                   tmp_functions, traversed_cfg_nodes
                                   )

        # Don't forget those small function chunks that are not called by anything.
        # There might be references to them from data, or simply references that we cannot find via static analysis

        secondary_function_nodes = set()
        # add all function chunks ("functions" that are not called from anywhere)
        for func_addr in tmp_functions:
            node = self.get_any_node(func_addr)
            if node is None:
                continue
            if node.addr not in blockaddr_to_function:
                secondary_function_nodes.add(node)

        missing_cfg_nodes = set(self.graph.nodes()) - traversed_cfg_nodes
        missing_cfg_nodes = { node for node in missing_cfg_nodes if node.function_address is not None }
        if missing_cfg_nodes:
            l.debug('%d CFGNodes are missing in the first traversal.', len(missing_cfg_nodes))
            secondary_function_nodes |=  missing_cfg_nodes

        min_stage_3_progress = 90.0
        max_stage_3_progress = 99.9

        nodes_count = len(secondary_function_nodes)
        for i, fn in enumerate(secondary_function_nodes):

            if self._show_progressbar or self._progress_callback:
                progress = min_stage_3_progress + (max_stage_3_progress - min_stage_3_progress) * (i * 1.0 / nodes_count)
                self._update_progress(progress)

            self._graph_bfs_custom(self.graph, [fn], self._graph_traversal_handler, blockaddr_to_function,
                                   tmp_functions
                                   )

        to_remove = set()

        # remove empty functions
        for function in self.kb.functions.values():
            if function.startpoint is None:
                to_remove.add(function.addr)

        for addr in to_remove:
            del self.kb.functions[addr]

        # Update CFGNode.function_address
        for node in self.model.nodes():
            if node.addr in blockaddr_to_function:
                node.function_address = blockaddr_to_function[node.addr].addr


Instruction:
Can you generate a brief explanation for the following Python 3 code
def set_field(self, state, field_name, field_type, value):
        field_ref = SimSootValue_InstanceFieldRef.get_ref(state=state,
                                                          obj_alloc_id=self.heap_alloc_id,
                                                          field_class_name=self.type,
                                                          field_name=field_name,
                                                          field_type=field_type)
        # store value in java memory
        state.memory.store(field_ref, value)

Response: Sets the value of the specified field in the state.


Instruction:
Explain what the following Python 3 code does
def get_field(self, state, field_name, field_type):
        # get field reference
        field_ref = SimSootValue_InstanceFieldRef.get_ref(state=state,
                                                          obj_alloc_id=self.heap_alloc_id,
                                                          field_class_name=self.type,
                                                          field_name=field_name,
                                                          field_type=field_type)
        # load value from java memory
        return state.memory.load(field_ref, none_if_missing=True)

Response: Gets the value of an instance field.


Instruction:
How would you explain what the following Python 3 function does
def store_field(self, state, field_name, field_type, value):
        field_ref = SimSootValue_InstanceFieldRef(self.heap_alloc_id, self.type, field_name, field_type)
        state.memory.store(field_ref, value)

Response: Store a field of a given object in the state s memory.


Instruction:
Create a Python 3 function for
loading a field of a given object

Response:
def load_field(self, state, field_name, field_type):
        """
        Load a field of a given object, without resolving hierachy

        :param state: angr state where we want to load the object attribute
        :type SimState
        :param field_name: name of the attribute
        :type str
        :param field_type: type of the attribute
        :type str
        """
        field_ref = SimSootValue_InstanceFieldRef(self.heap_alloc_id, self.type, field_name, field_type)
        return state.memory.load(field_ref, none_if_missing=False)


Instruction:
Can you write a function in Python 3 where it
creates a new object in the state.

Response:
def new_object(cls, state, type_, symbolic=False, init_object=False):
        """
        Creates a new object reference.
        :param state: State associated to the object.
        :param type_: Class of the object.
        :param init_object: Whether the objects initializer method should be run.
        :return: Reference to the new object.
        """
        # create reference
        obj_ref = cls(heap_alloc_id=state.memory.get_new_uuid(), type_=type_, symbolic=symbolic)
        # run initializer
        if init_object:
            l.info(">" * 15 + " Initialize object %r ... " + ">" * 15, obj_ref)
            # find initializer method
            # TODO: add support for non-default initializing methods
            init_method = resolve_method(state, '<init>', type_, init_class=False).address()

            # setup init state
            args = [SootArgument(obj_ref, obj_ref.type, is_this_ref=True)]
            init_state = state.project.simos.state_call(init_method, *args,
                                                        base_state=state,
                                                        ret_addr=SootAddressTerminator())
            # run init state
            simgr = state.project.factory.simgr(init_state)
            simgr.run()
            # copy results from initialization to the state
            state.memory.vm_static_table = simgr.deadended[0].memory.vm_static_table.copy()
            state.memory.heap = simgr.deadended[0].memory.heap.copy()
            l.debug("<" * 15 + " Initialize object %r ... done " + "<" * 15, obj_ref)
        return obj_ref


Instruction:
Create a Python 3 function to
configure the project to set up global settings.

Response:
def configure_project(self):
        """
        Configure the project to set up global settings (like SimProcedures).
        """
        self.return_deadend = self.project.loader.extern_object.allocate()
        self.project.hook(self.return_deadend, P['stubs']['CallReturn']())

        self.unresolvable_jump_target = self.project.loader.extern_object.allocate()
        self.project.hook(self.unresolvable_jump_target, P['stubs']['UnresolvableJumpTarget']())
        self.unresolvable_call_target = self.project.loader.extern_object.allocate()
        self.project.hook(self.unresolvable_call_target, P['stubs']['UnresolvableCallTarget']())

        def irelative_resolver(resolver_addr):
            # autohooking runs before this does, might have provided this already
            # in that case, we want to advertise the _resolver_ address, since it is now
            # providing the behavior of the actual function
            if self.project.is_hooked(resolver_addr):
                return resolver_addr

            base_state = self.state_blank(addr=0,
                add_options={o.SYMBOL_FILL_UNCONSTRAINED_MEMORY, o.SYMBOL_FILL_UNCONSTRAINED_REGISTERS})
            resolver = self.project.factory.callable(resolver_addr, concrete_only=True, base_state=base_state)
            try:
                if isinstance(self.arch, ArchS390X):
                    # On s390x ifunc resolvers expect hwcaps.
                    val = resolver(0)
                else:
                    val = resolver()
            except AngrCallableMultistateError:
                _l.error("Resolver at %#x failed to resolve! (multivalued)", resolver_addr)
                return None
            except AngrCallableError:
                _l.error("Resolver at %#x failed to resolve!", resolver_addr)
                return None

            return val._model_concrete.value

        self.project.loader.perform_irelative_relocs(irelative_resolver)


Instruction:
Implement a function in Python 3 to
initialize a blank state.

Response:
def state_blank(self, addr=None, initial_prefix=None, brk=None, stack_end=None, stack_size=1024*1024*8, stdin=None, **kwargs):
        """
        Initialize a blank state.

        All parameters are optional.

        :param addr:            The execution start address.
        :param initial_prefix:
        :param stack_end:       The end of the stack (i.e., the byte after the last valid stack address).
        :param stack_size:      The number of bytes to allocate for stack space
        :param brk:             The address of the process' break.
        :return:                The initialized SimState.

        Any additional arguments will be passed to the SimState constructor
        """
        # TODO: move ALL of this into the SimState constructor
        if kwargs.get('mode', None) is None:
            kwargs['mode'] = self.project._default_analysis_mode
        if kwargs.get('permissions_backer', None) is None:
            # just a dict of address ranges to permission bits
            permission_map = { }
            for obj in self.project.loader.all_objects:
                for seg in obj.segments:
                    perms = 0
                    # bit values based off of protection bit values from sys/mman.h
                    if seg.is_readable:
                        perms |= 1  # PROT_READ
                    if seg.is_writable:
                        perms |= 2  # PROT_WRITE
                    if seg.is_executable:
                        perms |= 4  # PROT_EXEC
                    permission_map[(seg.min_addr, seg.max_addr)] = perms
            permissions_backer = (self.project.loader.main_object.execstack, permission_map)
            kwargs['permissions_backer'] = permissions_backer
        if kwargs.get('memory_backer', None) is None:
            kwargs['memory_backer'] = self.project.loader.memory
        if kwargs.get('os_name', None) is None:
            kwargs['os_name'] = self.name

        state = SimState(self.project, **kwargs)

        if stdin is not None and not isinstance(stdin, SimFileBase):
            if type(stdin) is type:
                stdin = stdin(name='stdin', has_end=False)
            else:
                stdin = SimFileStream(name='stdin', content=stdin, has_end=True)

        last_addr = self.project.loader.main_object.max_addr
        actual_brk = (last_addr - last_addr % 0x1000 + 0x1000) if brk is None else brk
        state.register_plugin('posix', SimSystemPosix(stdin=stdin, brk=actual_brk))

        actual_stack_end = state.arch.initial_sp if stack_end is None else stack_end
        if o.ABSTRACT_MEMORY not in state.options:
            state.memory.mem._preapproved_stack = IRange(actual_stack_end - stack_size, actual_stack_end)

        if state.arch.sp_offset is not None:
            state.regs.sp = actual_stack_end

        if initial_prefix is not None:
            for reg in state.arch.default_symbolic_registers:
                state.registers.store(reg, state.solver.BVS(
                    initial_prefix + "_" + reg,
                    state.arch.bits,
                    explicit_name=True,
                    key=('reg', reg),
                    eternal=True))

        for reg, val, is_addr, mem_region in state.arch.default_register_values:

            region_base = None  # so pycharm does not complain

            if is_addr:
                if isinstance(mem_region, tuple):
                    # unpack it
                    mem_region, region_base = mem_region
                elif mem_region == 'global':
                    # Backward compatibility
                    region_base = 0
                else:
                    raise AngrSimOSError('You must specify the base address for memory region "%s". ' % mem_region)

            # special case for stack pointer override
            if actual_stack_end is not None and state.arch.registers[reg][0] == state.arch.sp_offset:
                continue

            if o.ABSTRACT_MEMORY in state.options and is_addr:
                address = claripy.ValueSet(state.arch.bits, mem_region, region_base, val)
                state.registers.store(reg, address)
            else:
                state.registers.store(reg, val)

        if addr is None: addr = self.project.entry
        state.regs.ip = addr

        # set up the "root history" node
        state.scratch.ins_addr = addr
        state.scratch.bbl_addr = addr
        state.scratch.stmt_idx = 0
        state.history.jumpkind = 'Ijk_Boring'

        return state


Instruction:
Here you have a function in Python 3, explain what it does
def prepare_call_state(self, calling_state, initial_state=None,
                           preserve_registers=(), preserve_memory=()):
        """
        This function prepares a state that is executing a call instruction.
        If given an initial_state, it copies over all of the critical registers to it from the
        calling_state. Otherwise, it prepares the calling_state for action.

        This is mostly used to create minimalistic for CFG generation. Some ABIs, such as MIPS PIE and
        x86 PIE, require certain information to be maintained in certain registers. For example, for
        PIE MIPS, this function transfer t9, gp, and ra to the new state.
        """

        if isinstance(self.arch, ArchMIPS32):
            if initial_state is not None:
                initial_state = self.state_blank()
            mips_caller_saves = ('s0', 's1', 's2', 's3', 's4', 's5', 's6', 's7', 'gp', 'sp', 'bp', 'ra')
            preserve_registers = preserve_registers + mips_caller_saves + ('t9',)

        if initial_state is None:
            new_state = calling_state.copy()
        else:
            new_state = initial_state.copy()
            for reg in set(preserve_registers):
                new_state.registers.store(reg, calling_state.registers.load(reg))
            for addr, val in set(preserve_memory):
                new_state.memory.store(addr, calling_state.memory.load(addr, val))

        return new_state

Response: This function prepares a state that is executing a call instruction.


Instruction:
Write a Python 3 function for
preparing the address space with the data necessary to perform relocations pointing to the given symbol_name.

Response:
def prepare_function_symbol(self, symbol_name, basic_addr=None):
        """
        Prepare the address space with the data necessary to perform relocations pointing to the given symbol

        Returns a 2-tuple. The first item is the address of the function code, the second is the address of the
        relocation target.
        """
        if basic_addr is None:
            basic_addr = self.project.loader.extern_object.get_pseudo_addr(symbol_name)
        return basic_addr, basic_addr


Instruction:
How would you explain what the following Python 3 function does
def setup_gdt(self, state, gdt):
        state.memory.store(gdt.addr+8, gdt.table)
        state.regs.gdt = gdt.gdt
        state.regs.cs = gdt.cs
        state.regs.ds = gdt.ds
        state.regs.es = gdt.es
        state.regs.ss = gdt.ss
        state.regs.fs = gdt.fs
        state.regs.gs = gdt.gs

Response: Setup the state. regs. gdt to the object in which to write the GDT.


Instruction:
Here you have a function in Python 3, explain what it does
def generate_gdt(self, fs, gs, fs_size=0xFFFFFFFF, gs_size=0xFFFFFFFF):
        A_PRESENT = 0x80
        A_DATA = 0x10
        A_DATA_WRITABLE = 0x2
        A_PRIV_0 = 0x0
        A_DIR_CON_BIT = 0x4
        F_PROT_32 = 0x4
        S_GDT = 0x0
        S_PRIV_0 = 0x0
        GDT_ADDR = 0x4000
        GDT_LIMIT = 0x1000

        normal_entry = self._create_gdt_entry(0, 0xFFFFFFFF,
                                             A_PRESENT | A_DATA | A_DATA_WRITABLE | A_PRIV_0 | A_DIR_CON_BIT,
                                             F_PROT_32)
        stack_entry = self._create_gdt_entry(0, 0xFFFFFFFF, A_PRESENT | A_DATA | A_DATA_WRITABLE | A_PRIV_0,
                                            F_PROT_32)
        fs_entry = self._create_gdt_entry(fs, fs_size,
                                         A_PRESENT | A_DATA | A_DATA_WRITABLE | A_PRIV_0 | A_DIR_CON_BIT, F_PROT_32)
        gs_entry = self._create_gdt_entry(gs, gs_size,
                                         A_PRESENT | A_DATA | A_DATA_WRITABLE | A_PRIV_0 | A_DIR_CON_BIT, F_PROT_32)

        table = normal_entry + stack_entry + fs_entry + gs_entry
        gdt =  (GDT_ADDR << 16 | GDT_LIMIT)
        selector = self._create_selector(1, S_GDT | S_PRIV_0)
        cs = selector
        ds = selector
        es = selector
        selector = self._create_selector(2, S_GDT | S_PRIV_0)
        ss = selector
        selector = self._create_selector(3, S_GDT | S_PRIV_0)
        fs = selector
        selector = self._create_selector(4, S_GDT | S_PRIV_0)
        gs = selector
        global_descriptor_table = GlobalDescriptorTable(GDT_ADDR, GDT_LIMIT, table, gdt, cs, ds, es, ss, fs, gs)
        return global_descriptor_table

Response: Generate a GlobalDescriptorTable object and populate it using the value of the fs and gs segments.


Instruction:
Can you implement a function in Python 3 that
registers a struct definition globally

Response:
def define_struct(defn):
    """
    Register a struct definition globally

    >>> define_struct('struct abcd {int x; int y;}')
    """
    struct = parse_type(defn)
    ALL_TYPES[struct.name] = struct
    return struct


Instruction:
Write a Python 3 script for
running a string through the C preprocessor that ships with pycparser but is weirdly inaccessible?

Response:
def do_preprocess(defn):
    """
    Run a string through the C preprocessor that ships with pycparser but is weirdly inaccessible?
    """
    from pycparser.ply import lex, cpp
    lexer = lex.lex(cpp)
    p = cpp.Preprocessor(lexer)
    # p.add_path(dir) will add dir to the include search path
    p.parse(defn)
    return ''.join(tok.value for tok in p.parser if tok.type not in p.ignore)


Instruction:
Write a Python 3 script to
parse a series of C definitions returns a tuple of two type mappings one for variable definitions and one for type definitions.

Response:
def parse_file(defn, preprocess=True):
    """
    Parse a series of C definitions, returns a tuple of two type mappings, one for variable
    definitions and one for type definitions.
    """
    if pycparser is None:
        raise ImportError("Please install pycparser in order to parse C definitions")

    defn = '\n'.join(x for x in defn.split('\n') if _include_re.match(x) is None)

    if preprocess:
        defn = do_preprocess(defn)

    preamble, ignoreme = make_preamble()
    node = pycparser.c_parser.CParser().parse(preamble + defn)
    if not isinstance(node, pycparser.c_ast.FileAST):
        raise ValueError("Something went horribly wrong using pycparser")
    out = {}
    extra_types = {}
    for piece in node.ext:
        if isinstance(piece, pycparser.c_ast.FuncDef):
            out[piece.decl.name] = _decl_to_type(piece.decl.type, extra_types)
        elif isinstance(piece, pycparser.c_ast.Decl):
            ty = _decl_to_type(piece.type, extra_types)
            if piece.name is not None:
                out[piece.name] = ty
        elif isinstance(piece, pycparser.c_ast.Typedef):
            extra_types[piece.name] = _decl_to_type(piece.type, extra_types)

    for ty in ignoreme:
        del extra_types[ty]
    return out, extra_types


Instruction:
Can you generate the documentation for the following Python 3 function
def parse_type(defn, preprocess=True):
    if pycparser is None:
        raise ImportError("Please install pycparser in order to parse C definitions")

    defn = 'typedef ' + defn.strip('; \n\t\r') + ' QQQQ;'

    if preprocess:
        defn = do_preprocess(defn)

    node = pycparser.c_parser.CParser().parse(make_preamble()[0] + defn)
    if not isinstance(node, pycparser.c_ast.FileAST) or \
            not isinstance(node.ext[-1], pycparser.c_ast.Typedef):
        raise ValueError("Something went horribly wrong using pycparser")

    decl = node.ext[-1].type
    return _decl_to_type(decl)

Response: Parse a simple type expression into a SimType


Instruction:
Write a Python 3 script for
returning the alignment of the type in bytes.

Response:
def alignment(self):
        """
        The alignment of the type in bytes.
        """
        if self._arch is None:
            return NotImplemented
        return self.size // self._arch.byte_width


Instruction:
Can you write a function in Python 3 where it
synchronizes the concrete registers with the one getting from the concrete process memory.

Response:
def sync(self):
        """
        Handle the switch between the concrete execution and angr.
        This method takes care of:
        1- Synchronize registers.
        2- Set a concrete target to the memory backer so the memory reads are redirected in the concrete process memory.
        3- If possible restore the SimProcedures with the real addresses inside the concrete process.
        4- Set an inspect point to sync the segments register as soon as they are read during the symbolic execution.
        5- Flush all the pages loaded until now.

        :return:
        """

        def _sync_segments(state):
            """
            Segment registers synchronization is on demand as soon as the
            symbolic execution access a segment register.
            """
            concr_target = state.project.concrete_target

            if isinstance(state.arch, ArchAMD64):
                state.project.simos.initialize_segment_register_x64(state, concr_target)
            elif isinstance(state.arch, ArchX86):
                gdt = state.project.simos.initialize_gdt_x86(state, concr_target)
                state.concrete.whitelist.append((gdt.addr, gdt.addr + gdt.limit))

            state.inspect.remove_breakpoint('reg_read', bp=state.concrete.fs_register_bp)
            state.concrete.segment_registers_initialized = True

            state.concrete.fs_register_bp = None

        l.debug("Sync the state with the concrete memory inside the Concrete plugin")

        target = self.state.project.concrete_target

        # Setting a concrete memory backend
        self.state.memory.mem._memory_backer.set_concrete_target(target)

        # Sync angr registers with the one getting from the concrete target
        # registers that we don't want to concretize.
        l.debug("Synchronizing general purpose registers")

        to_sync_register = list(filter(lambda x: x.concrete, self.state.arch.register_list))

        for register in to_sync_register:

            # before let's sync all the subregisters of the current register.
            # sometimes this can be helpful ( i.e. ymmm0 e xmm0 )
            if register.subregisters:
                subregisters_names = map(lambda x: x[0], register.subregisters)
                self._sync_registers(subregisters_names, target)

            # finally let's synchronize the whole register
            self._sync_registers([register.name], target)

        if self.synchronize_cle:
            self._sync_cle(target)

        # Synchronize the imported functions addresses (.got, IAT) in the
        # concrete process with ones used in the SimProcedures dictionary
        if self.state.project._should_use_sim_procedures and not self.state.project.loader.main_object.pic:
            l.debug("Restoring SimProc using concrete memory")

            for reloc in self.state.project.loader.main_object.relocs:
                if reloc.symbol:  # consider only reloc with a symbol
                    l.debug("Trying to re-hook SimProc %s", reloc.symbol.name)
                    # l.debug("reloc.rebased_addr: %#x " % reloc.rebased_addr)
                    func_address = target.read_memory(reloc.rebased_addr, self.state.project.arch.bits / 8)
                    func_address = struct.unpack(self.state.project.arch.struct_fmt(), func_address)[0]
                    l.debug("Function address hook is now: %#x ", func_address)
                    self.state.project.rehook_symbol(func_address, reloc.symbol.name)

                    if self.synchronize_cle and not self.state.project.loader.main_object.contains_addr(func_address):
                        old_func_symbol = self.state.project.loader.find_symbol(reloc.symbol.name)

                        if old_func_symbol:  # if we actually have a symbol
                            owner_obj = old_func_symbol.owner

                            # calculating the new real address
                            new_relative_address = func_address - owner_obj.mapped_base

                            new_func_symbol = cle.backends.Symbol(owner_obj, old_func_symbol.name, new_relative_address,
                                                                  old_func_symbol.size, old_func_symbol.type)

                            for new_reloc in self.state.project.loader.find_relevant_relocations(old_func_symbol.name):
                                if new_reloc.symbol.name == new_func_symbol.name and \
                                        new_reloc.value != new_func_symbol.rebased_addr:

                                    l.debug("Updating CLE symbols metadata, moving %s from 0x%x to 0x%x",
                                            new_reloc.symbol.name,
                                            new_reloc.value,
                                            new_func_symbol.rebased_addr)

                                    new_reloc.resolve(new_func_symbol)
                                    new_reloc.relocate([])

        else:
            l.debug("SimProc not restored, you are going to simulate also the code of external libraries!")

        # flush the angr memory in order to synchronize them with the content of the
        # concrete process memory when a read/write to the page is performed
        self.state.memory.flush_pages(self.whitelist)
        l.info("Exiting SimEngineConcrete: simulated address %x concrete address %x ", self.state.addr,
               target.read_register("pc"))

        # now we have to register a SimInspect in order to synchronize the segments register
        # on demand when the symbolic execution accesses it
        if not self.segment_registers_callback_initialized:
            segment_register_name = self.state.project.simos.get_segment_register_name()
            if segment_register_name:
                self.fs_register_bp = self.state.inspect.b('reg_read',
                                                           reg_read_offset=segment_register_name,
                                                           action=_sync_segments)

                self.segment_registers_callback_initialized = True

                l.debug("Set SimInspect breakpoint to the new state!")
            else:
                l.error("Can't set breakpoint to synchronize segments registers, horrible things will happen.")


Instruction:
Can you create a Python 3 function that
calculates the similarity between two states.

Response:
def similarity(state_a, state_b):
        """
        The (L2) distance between the counts of the state addresses in the history of the path.
        :param state_a: The first state to compare
        :param state_b: The second state to compare
        """
        count_a = Counter(state_a.history.bbl_addrs)
        count_b = Counter(state_b.history.bbl_addrs)
        normal_distance = sum((count_a.get(addr, 0) - count_b.get(addr, 0)) ** 2
                              for addr in set(list(count_a.keys()) + list(count_b.keys()))) ** 0.5
        return 1.0 / (1 + normal_distance)


Instruction:
Can you implement a function in Python 3 that
resolves the given method based on the given characteristics.

Response:
def resolve_method(state, method_name, class_name, params=(), ret_type=None,
                   include_superclasses=True, init_class=True,
                   raise_exception_if_not_found=False):
    """
    Resolves the method based on the given characteristics (name, class and
    params) The method may be defined in one of the superclasses of the given
    class (TODO: support interfaces).

    :rtype: archinfo.arch_soot.SootMethodDescriptor
    """
    base_class = state.javavm_classloader.get_class(class_name)
    if include_superclasses:
        class_hierarchy = state.javavm_classloader.get_class_hierarchy(base_class)
    else:
        class_hierarchy = [base_class]
    # walk up in class hierarchy, until method is found
    for class_descriptor in class_hierarchy:
        java_binary = state.project.loader.main_object
        soot_method = java_binary.get_soot_method(method_name, class_descriptor.name,
                                                  params, none_if_missing=True)
        if soot_method is not None:
            # init the class
            if init_class:
                state.javavm_classloader.init_class(class_descriptor)
            return SootMethodDescriptor.from_soot_method(soot_method)

    # method could not be found
    # => we are executing code that is not loaded (typically library code)
    # => fallback: continue with infos available from the invocation, so we
    #              still can use SimProcedures
    if raise_exception_if_not_found:
        raise SootMethodNotLoadedException()
    else:
        return SootMethodDescriptor(class_name, method_name, params, ret_type=ret_type)


Instruction:
Make a summary of the following Python 3 code
def from_arg_kinds(cls, arch, fp_args, ret_fp=False, sizes=None, sp_delta=None, func_ty=None):
        basic = cls(arch, sp_delta=sp_delta, func_ty=func_ty)
        basic.args = basic.arg_locs(fp_args, sizes)
        basic.ret_val = basic.fp_return_val if ret_fp else basic.return_val
        return basic

Response: Create an instance of the class from the given arguments.


Instruction:
Can you generate the documentation for the following Python 3 function
def int_args(self):
        if self.ARG_REGS is None:
            raise NotImplementedError()
        for reg in self.ARG_REGS:            # pylint: disable=not-an-iterable
            yield SimRegArg(reg, self.arch.bytes)

Response: Iterate through all possible arg positions that can only be used to store integer or pointer values.


Instruction:
Can you implement a function in Python 3 that
iterates through all possible arg positions that can be used to store any kind of argument in a specific class.

Response:
def both_args(self):
        """
        Iterate through all the possible arg positions that can be used to store any kind of argument
        Does not take into account customizations.

        Returns an iterator of SimFunctionArguments
        """
        turtle = self.STACKARG_SP_BUFF + self.STACKARG_SP_DIFF
        while True:
            yield SimStackArg(turtle, self.arch.bytes)
            turtle += self.arch.bytes


Instruction:
Write a Python 3 function that can
iterate through all the possible arg positions that can only be used to store floating point values.

Response:
def fp_args(self):
        """
        Iterate through all the possible arg positions that can only be used to store floating point values
        Does not take into account customizations.

        Returns an iterator of SimFunctionArguments
        """
        if self.FP_ARG_REGS is None:
            raise NotImplementedError()
        for reg in self.FP_ARG_REGS:        # pylint: disable=not-an-iterable
            yield SimRegArg(reg, self.arch.registers[reg][1])


Instruction:
Can you write a function in Python 3 where it
returns True if the argument is a floating point argument False otherwise.

Response:
def is_fp_arg(self, arg):
        """
        This should take a SimFunctionArgument instance and return whether or not that argument is a floating-point
        argument.

        Returns True for MUST be a floating point arg,
                False for MUST NOT be a floating point arg,
                None for when it can be either.
        """
        if arg in self.int_args:
            return False
        if arg in self.fp_args or arg == self.FP_RETURN_VAL:
            return True
        return None


Instruction:
Given the following Python 3 function, write the documentation
def stack_space(self, args):
        out = self.STACKARG_SP_DIFF
        for arg in args:
            if isinstance(arg, SimStackArg):
                out = max(out, arg.stack_offset + self.arch.bytes)

        out += self.STACKARG_SP_BUFF
        return out

Response: Returns the number of bytes that should be allocated on the stack.


Instruction:
How would you code a function in Python 3 to
return a list of locations for each argument of the current function.

Response:
def arg_locs(self, is_fp=None, sizes=None):
        """
        Pass this a list of whether each parameter is floating-point or not, and get back a list of
        SimFunctionArguments. Optionally, pass a list of argument sizes (in bytes) as well.

        If you've customized this CC, this will sanity-check the provided locations with the given list.
        """
        session = self.arg_session
        if self.func_ty is None:
            # No function prototype is provided. `is_fp` must be provided.
            if is_fp is None:
                raise ValueError('"is_fp" must be provided when no function prototype is available.')
        else:
            # let's rely on the func_ty for the number of arguments and whether each argument is FP or not
            is_fp = [ True if isinstance(arg, (SimTypeFloat, SimTypeDouble)) else False for arg in self.func_ty.args ]

        if sizes is None: sizes = [self.arch.bytes] * len(is_fp)
        return [session.next_arg(ifp, size=sz) for ifp, sz in zip(is_fp, sizes)]


Instruction:
Can you generate a brief explanation for the following Python 3 code
def arg(self, state, index, stack_base=None):
        session = self.arg_session
        if self.args is None:
            arg_loc = [session.next_arg(False) for _ in range(index + 1)][-1]
        else:
            arg_loc = self.args[index]

        return arg_loc.get_value(state, stack_base=stack_base)

Response: Returns a bitvector expression representing the nth argument of a function.


Instruction:
Can you create a Python 3 function that
returns a list of bitvector expressions representing the arguments of a function.

Response:
def get_args(self, state, is_fp=None, sizes=None, stack_base=None):
        """
        `is_fp` should be a list of booleans specifying whether each corresponding argument is floating-point -
        True for fp and False for int. For a shorthand to assume that all the parameters are int, pass the number of
        parameters as an int.

        If you've customized this CC, you may omit this parameter entirely. If it is provided, it is used for
        sanity-checking.

        `sizes` is an optional list of argument sizes, in bytes. Be careful about using this if you've made explicit
        the arg locations, since it might decide to combine two locations into one if an arg is too big.

        `stack_base` is an optional pointer to the top of the stack at the function start. If it is not
        specified, use the current stack pointer.

        Returns a list of bitvector expressions representing the arguments of a function.
        """
        if sizes is None and self.func_ty is not None:
            sizes = [arg.size for arg in self.func_ty.args]
        if is_fp is None:
            if self.args is None:
                if self.func_ty is None:
                    raise ValueError("You must either customize this CC or pass a value to is_fp!")
                else:
                    arg_locs = self.arg_locs([False]*len(self.func_ty.args))
            else:
                arg_locs = self.args

        elif type(is_fp) is int:
            if self.args is not None and len(self.args) != is_fp:
                raise ValueError("Bad number of args requested: got %d, expected %d" % (is_fp, len(self.args)))
            arg_locs = self.arg_locs([False]*is_fp, sizes)
        else:
            arg_locs = self.arg_locs(is_fp, sizes)

        return [loc.get_value(state, stack_base=stack_base) for loc in arg_locs]


Instruction:
Given the following Python 3 function, write the documentation
def setup_callsite(self, state, ret_addr, args, stack_base=None, alloc_base=None, grow_like_stack=True):

        # STEP 0: clerical work

        if isinstance(self, SimCCSoot):
            SimEngineSoot.setup_callsite(state, args, ret_addr)
            return

        allocator = AllocHelper(self.arch.bits, self.arch.memory_endness == 'Iend_LE')

        #
        # STEP 1: convert all values into serialized form
        # this entails creating the vals list of simple values to store and also populating the allocator's
        # understanding of what aux data needs to be stored
        # This is also where we compute arg locations (arg_locs)
        #

        if self.func_ty is not None:
            vals = [self._standardize_value(arg, ty, state, allocator.dump) for arg, ty in zip(args, self.func_ty.args)]
        else:
            vals = [self._standardize_value(arg, None, state, allocator.dump) for arg in args]

        arg_session = self.arg_session
        arg_locs = [None]*len(args)
        for i, (arg, val) in enumerate(zip(args, vals)):
            if self.is_fp_value(arg) or \
                    (self.func_ty is not None and isinstance(self.func_ty.args[i], SimTypeFloat)):
                arg_locs[i] = arg_session.next_arg(is_fp=True, size=val.length // state.arch.byte_width)
                continue
            if val.length > state.arch.bits or (self.func_ty is None and isinstance(arg, (bytes, str, list, tuple))):
                vals[i] = allocator.dump(val, state)
            elif val.length < state.arch.bits:
                if self.arch.memory_endness == 'Iend_LE':
                    vals[i] = val.concat(claripy.BVV(0, state.arch.bits - val.length))
                else:
                    vals[i] = claripy.BVV(0, state.arch.bits - val.length).concat(val)
            arg_locs[i] = arg_session.next_arg(is_fp=False, size=vals[i].length // state.arch.byte_width)

        #
        # STEP 2: decide on memory storage locations
        # implement the contract for stack_base/alloc_base/grow_like_stack
        # after this, stack_base should be the final stack pointer, alloc_base should be the final aux storage location,
        # and the stack pointer should be updated
        #

        if stack_base is None:
            if alloc_base is None:
                alloc_size = allocator.size()
                state.regs.sp -= alloc_size
                alloc_base = state.regs.sp
                grow_like_stack = False

            state.regs.sp -= self.stack_space(arg_locs)

            # handle alignment
            alignment = (state.regs.sp + self.STACKARG_SP_DIFF) % self.STACK_ALIGNMENT
            state.regs.sp -= alignment

        else:
            state.regs.sp = stack_base

            if alloc_base is None:
                alloc_base = stack_base + self.stack_space(arg_locs)
                grow_like_stack = False

        if grow_like_stack:
            alloc_base -= allocator.size()
        if type(alloc_base) is int:
            alloc_base = claripy.BVV(alloc_base, state.arch.bits)

        for i, val in enumerate(vals):
            vals[i] = allocator.translate(val, alloc_base)

        #
        # STEP 3: store everything!
        #

        allocator.apply(state, alloc_base)

        for loc, val in zip(arg_locs, vals):
            if val.length > loc.size * 8:
                raise ValueError("Can't fit value {} into location {}".format(repr(val), repr(loc)))
            loc.set_value(state, val, endness='Iend_BE', stack_base=stack_base)
        self.return_addr.set_value(state, ret_addr, stack_base=stack_base)

Response: This function sets up the callsite for the caller.


Instruction:
Can you generate the documentation for the following Python 3 function
def get_return_val(self, state, is_fp=None, size=None, stack_base=None):
        ty = self.func_ty.returnty if self.func_ty is not None else None
        if self.ret_val is not None:
            loc = self.ret_val
        elif is_fp is not None:
            loc = self.FP_RETURN_VAL if is_fp else self.RETURN_VAL
        elif ty is not None:
            loc = self.FP_RETURN_VAL if isinstance(ty, SimTypeFloat) else self.RETURN_VAL
        else:
            loc = self.RETURN_VAL

        if loc is None:
            raise NotImplementedError("This SimCC doesn't know how to get this value - should be implemented")

        val = loc.get_value(state, stack_base=stack_base, size=None if ty is None else ty.size//state.arch.byte_width)
        if self.is_fp_arg(loc) or self.is_fp_value(val) or isinstance(ty, SimTypeFloat):
            val = val.raw_to_fp()
        return val

Response: Get the return value out of the given state


Instruction:
Can you generate a brief explanation for the following Python 3 code
def set_return_val(self, state, val, is_fp=None, size=None, stack_base=None):
        ty = self.func_ty.returnty if self.func_ty is not None else None
        try:
            betterval = self._standardize_value(val, ty, state, None)
        except AttributeError:
            raise ValueError("Can't fit value %s into a return value" % repr(val))

        if self.ret_val is not None:
            loc = self.ret_val
        elif is_fp is not None:
            loc = self.FP_RETURN_VAL if is_fp else self.RETURN_VAL
        elif ty is not None:
            loc = self.FP_RETURN_VAL if isinstance(ty, SimTypeFloat) else self.RETURN_VAL
        else:
            loc = self.FP_RETURN_VAL if self.is_fp_value(val) else self.RETURN_VAL

        if loc is None:
            raise NotImplementedError("This SimCC doesn't know how to store this value - should be implemented")
        loc.set_value(state, betterval, endness='Iend_BE', stack_base=stack_base)

Response: Set the return value into the given state


Instruction:
Write a Python 3 function for
finding the most - fit calling convention and return the corresponding SimCC instance.

Response:
def find_cc(arch, args, sp_delta):
        """
        Pinpoint the best-fit calling convention and return the corresponding SimCC instance, or None if no fit is
        found.

        :param Arch arch:       An ArchX instance. Can be obtained from archinfo.
        :param list args:       A list of arguments.
        :param int sp_delta:    The change of stack pointer before and after the call is made.
        :return:                A calling convention instance, or None if none of the SimCC subclasses seems to fit the
                                arguments provided.
        :rtype:                 SimCC or None
        """
        if arch.name not in CC:
            return None
        possible_cc_classes = CC[arch.name]
        for cc_cls in possible_cc_classes:
            if cc_cls._match(arch, args, sp_delta):
                return cc_cls(arch, args=args, sp_delta=sp_delta)
        return None


Instruction:
Given the following Python 3 function, write the documentation
def get_arg_info(self, state, is_fp=None, sizes=None):
        argument_types = self.func_ty.args
        argument_names = self.func_ty.arg_names if self.func_ty.arg_names else ['unknown'] * len(self.func_ty.args)
        argument_locations = self.arg_locs(is_fp=is_fp, sizes=sizes)
        argument_values = self.get_args(state, is_fp=is_fp, sizes=sizes)
        return list(zip(argument_types, argument_names, argument_locations, argument_values))

Response:
This method returns the information from various locations
        is_fp and sizes are passed to self. get_args and returns the information of the nth argument in the list


Instruction:
Make a summary of the following Python 3 code
def add_successor(self, state, target, guard, jumpkind, add_guard=True, exit_stmt_idx=None, exit_ins_addr=None,
                      source=None):
        """
        Add a successor state of the SimRun.
        This procedure stores method parameters into state.scratch, does some housekeeping,
        and calls out to helper functions to prepare the state and categorize it into the appropriate
        successor lists.

        :param SimState state:    The successor state.
        :param target:            The target (of the jump/call/ret).
        :param guard:             The guard expression.
        :param str jumpkind:      The jumpkind (call, ret, jump, or whatnot).
        :param bool add_guard:    Whether to add the guard constraint (default: True).
        :param int exit_stmt_idx: The ID of the exit statement, an integer by default. 'default'
                                  stands for the default exit, and None means it's not from a
                                  statement (for example, from a SimProcedure).
        :param int exit_ins_addr: The instruction pointer of this exit, which is an integer by default.
        :param int source:        The source of the jump (i.e., the address of the basic block).
        """

        # First, trigger the SimInspect breakpoint
        state._inspect('exit', BP_BEFORE, exit_target=target, exit_guard=guard, exit_jumpkind=jumpkind)
        state.scratch.target = state._inspect_getattr("exit_target", target)
        state.scratch.guard = state._inspect_getattr("exit_guard", guard)
        state.history.jumpkind = state._inspect_getattr("exit_jumpkind", jumpkind)
        state.history.jump_target = state.scratch.target
        state.history.jump_guard = state.scratch.guard

        # track some vex-specific stuff here for now
        state.scratch.source = source if source is not None else self.addr
        state.scratch.exit_stmt_idx = exit_stmt_idx
        state.scratch.exit_ins_addr = exit_ins_addr

        self._preprocess_successor(state, add_guard=add_guard)

        if state.history.jumpkind == 'Ijk_SigFPE_IntDiv' and o.PRODUCE_ZERODIV_SUCCESSORS not in state.options:
            return

        self._categorize_successor(state)
        state._inspect('exit', BP_AFTER, exit_target=target, exit_guard=guard, exit_jumpkind=jumpkind)
        if state.supports_inspect:
            state.inspect.downsize()

Response: Add a successor state to the state.


Instruction:
Here you have a function in Python 3, explain what it does
def _categorize_successor(self, state):

        self.all_successors.append(state)
        target = state.scratch.target

        # categorize the state
        if o.APPROXIMATE_GUARDS in state.options and state.solver.is_false(state.scratch.guard, exact=False):
            if o.VALIDATE_APPROXIMATIONS in state.options:
                if state.satisfiable():
                    raise Exception('WTF')
            self.unsat_successors.append(state)
        elif o.APPROXIMATE_SATISFIABILITY in state.options and not state.solver.satisfiable(exact=False):
            if o.VALIDATE_APPROXIMATIONS in state.options:
                if state.solver.satisfiable():
                    raise Exception('WTF')
            self.unsat_successors.append(state)
        elif not state.scratch.guard.symbolic and state.solver.is_false(state.scratch.guard):
            self.unsat_successors.append(state)
        elif o.LAZY_SOLVES not in state.options and not state.satisfiable():
            self.unsat_successors.append(state)
        elif o.NO_SYMBOLIC_JUMP_RESOLUTION in state.options and state.solver.symbolic(target):
            self.unconstrained_successors.append(state)
        elif not state.solver.symbolic(target) and not state.history.jumpkind.startswith("Ijk_Sys"):
            # a successor with a concrete IP, and it's not a syscall
            self.successors.append(state)
            self.flat_successors.append(state)
        elif state.history.jumpkind.startswith("Ijk_Sys"):
            # syscall
            self.successors.append(state)

            # Misuse the ip_at_syscall register to save the return address for this syscall
            # state.ip *might be* changed to be the real address of syscall SimProcedures by syscall handling code in
            # angr
            state.regs.ip_at_syscall = state.ip

            try:
                symbolic_syscall_num, concrete_syscall_nums = self._resolve_syscall(state)
                if concrete_syscall_nums is not None:
                    for i, n in enumerate(concrete_syscall_nums):
                        split_state = state if i == len(concrete_syscall_nums) - 1 else state.copy()
                        split_state.add_constraints(symbolic_syscall_num == n)
                        if split_state.supports_inspect:
                            split_state.inspect.downsize()
                        self._fix_syscall_ip(split_state)

                        self.flat_successors.append(split_state)
                else:
                    # We cannot resolve the syscall number
                    # However, we still put it to the flat_successors list, and angr.SimOS.handle_syscall will pick it
                    # up, and create a "unknown syscall" stub for it.
                    self._fix_syscall_ip(state)
                    self.flat_successors.append(state)
            except AngrUnsupportedSyscallError:
                self.unsat_successors.append(state)

        else:
            # a successor with a symbolic IP
            _max_targets = state.options.symbolic_ip_max_targets
            _max_jumptable_targets = state.options.jumptable_symbolic_ip_max_targets
            try:
                if o.NO_IP_CONCRETIZATION in state.options:
                    # Don't try to concretize the IP
                    cond_and_targets = [ (claripy.true, target) ]
                    max_targets = 0
                elif o.KEEP_IP_SYMBOLIC in state.options:
                    s = claripy.Solver()
                    addrs = s.eval(target, _max_targets + 1, extra_constraints=tuple(state.ip_constraints))
                    if len(addrs) > _max_targets:
                        # It is not a library
                        l.debug("It is not a Library")
                        addrs = state.solver.eval_upto(target, _max_targets + 1)
                        l.debug("addrs :%s", addrs)
                    cond_and_targets = [ (target == addr, addr) for addr in addrs ]
                    max_targets = _max_targets
                else:
                    cond_and_targets = self._eval_target_jumptable(state, target, _max_jumptable_targets + 1)
                    if cond_and_targets is None:
                        # Fallback to the traditional and slow method
                        cond_and_targets = self._eval_target_brutal(state, target, _max_targets + 1)
                        max_targets = _max_targets
                    else:
                        max_targets = _max_jumptable_targets

                if len(cond_and_targets) > max_targets:
                    l.warning(
                        "Exit state has over %d possible solutions. Likely unconstrained; skipping. %s",
                        max_targets,
                        target.shallow_repr()
                    )
                    self.unconstrained_successors.append(state)
                else:
                    for cond, a in cond_and_targets:
                        split_state = state.copy()
                        if o.KEEP_IP_SYMBOLIC in split_state.options:
                            split_state.regs.ip = target
                        else:
                            split_state.add_constraints(cond, action=True)
                            split_state.regs.ip = a
                        if split_state.supports_inspect:
                            split_state.inspect.downsize()
                        self.flat_successors.append(split_state)
                    self.successors.append(state)
            except SimSolverModeError:
                self.unsat_successors.append(state)

        return state

Response: Add the state to the list of successors and the successors.


Instruction:
Implement a Python 3 function for
resolving syscall information from the state and set the IP of the state accordingly.

Response:
def _fix_syscall_ip(state):
        """
        Resolve syscall information from the state, get the IP address of the syscall SimProcedure, and set the IP of
        the state accordingly. Don't do anything if the resolution fails.

        :param SimState state: the program state.
        :return: None
        """

        try:
            bypass = o.BYPASS_UNSUPPORTED_SYSCALL in state.options
            stub = state.project.simos.syscall(state, allow_unsupported=bypass)
            if stub: # can be None if simos is not a subclass of SimUserspace
                state.ip = stub.addr # fix the IP
        except AngrUnsupportedSyscallError:
            pass


Instruction:
Create a Python 3 function to
evaluate symbolic jump targets.

Response:
def _eval_target_jumptable(state, ip, limit):
        """
        A *very* fast method to evaluate symbolic jump targets if they are a) concrete targets, or b) targets coming
        from jump tables.

        :param state:   A SimState instance.
        :param ip:      The AST of the instruction pointer to evaluate.
        :param limit:   The maximum number of concrete IPs.
        :return:        A list of conditions and the corresponding concrete IPs, or None which indicates fallback is
                        necessary.
        :rtype:         list or None
        """

        if ip.symbolic is False:
            return [ (claripy.ast.bool.true, ip) ]  # concrete

        # Detect whether ip is in the form of "if a == 1 then addr_0 else if a == 2 then addr_1 else ..."
        cond_and_targets = [ ]  # tuple of (condition, target)

        ip_ = ip
        # Handle the outer Reverse
        outer_reverse = False
        if ip_.op == "Reverse":
            ip_ = ip_.args[0]
            outer_reverse = True

        fallback = False
        target_variable = None
        concretes = set()
        reached_sentinel = False

        for cond, target in claripy.reverse_ite_cases(ip_):
            # We must fully unpack the entire AST to make sure it indeed complies with the form above
            if reached_sentinel:
                # We should not have any other value beyond the sentinel - maybe one of the possible targets happens to
                # be the same as the sentinel value?
                fallback = True
                break

            if target.symbolic is False and state.solver.eval(target) == DUMMY_SYMBOLIC_READ_VALUE:
                # Ignore the dummy value, which acts as the sentinel of this ITE tree
                reached_sentinel = True
                continue

            if cond.op != "__eq__":
                # We only support equivalence right now. Fallback
                fallback = True
                break

            if cond.args[0].symbolic is True and cond.args[1].symbolic is False:
                variable, value = cond.args
            elif cond.args[0].symbolic is False and cond.args[1].symbolic is True:
                value, variable = cond.args
            else:
                # Cannot determine variable and value. Fallback
                fallback = True
                break

            if target_variable is None:
                target_variable = variable
            elif target_variable is not variable:
                # it's checking a different variable. Fallback
                fallback = True
                break

            # Make sure the conditions are mutually exclusive
            value_concrete = state.solver.eval(value)
            if value_concrete in concretes:
                # oops... the conditions are not mutually exclusive
                fallback = True
                break
            concretes.add(value_concrete)

            if target.symbolic is True:
                # Cannot handle symbolic targets. Fallback
                fallback = True
                break

            cond_and_targets.append((cond, target if not outer_reverse else state.solver.Reverse(target)))

        if reached_sentinel is False:
            # huh?
            fallback = True

        if fallback:
            return None
        else:
            return cond_and_targets[ : limit]


Instruction:
Make a summary of the following Python 3 code
def _repeat_bytes(byt, rep):

        if rep == 1:
            return byt

        remainder = rep % 2
        quotient = rep // 2

        r_ = memset._repeat_bytes(byt, quotient)
        if remainder == 1:
            r = r_ << ((quotient + 1) * 8)
            r |= (r_ << 8) + byt
        else:
            r = r_ << (quotient * 8)
            r |= r_
        return r

Response: This function is used to get a long number for a byte being repeated for many times.


Instruction:
Can you generate a brief explanation for the following Python 3 code
def copy(self):
        s = MemoryData(self.address, self.size, self.sort, pointer_addr=self.pointer_addr, max_size=self.max_size)
        s.content = self.content

        return s

Response: Make a copy of the MemoryData instance.


Instruction:
Here you have a function in Python 3, explain what it does
def store_mo(self, state, new_mo, overwrite=True): #pylint:disable=unused-argument
        start, end = self._resolve_range(new_mo)
        if overwrite:
            self.store_overwrite(state, new_mo, start, end)
        else:
            self.store_underwrite(state, new_mo, start, end)

Response: Stores a memory object in the state.


Instruction:
How would you explain what the following Python 3 function does
def load_mo(self, state, page_idx):

        try:
            key = next(self._storage.irange(maximum=page_idx, reverse=True))
        except StopIteration:
            return None
        else:
            return self._storage[key]

Response: Load a memory object from memory.


Instruction:
Write a Python 3 script to
load the slice of the memory.

Response:
def load_slice(self, state, start, end):
        """
        Return the memory objects overlapping with the provided slice.

        :param start: the start address
        :param end: the end address (non-inclusive)
        :returns: tuples of (starting_addr, memory_object)
        """
        keys = list(self._storage.irange(start, end-1))
        if not keys or keys[0] != start:
            try:
                key = next(self._storage.irange(maximum=start, reverse=True))
            except StopIteration:
                pass
            else:
                if self._storage[key].includes(start):
                    keys.insert(0, key)
        return [(max(start, key), self._storage[key]) for key in keys]


Instruction:
Can you write a function in Python 3 where it
loads a memory object from memory.

Response:
def load_mo(self, state, page_idx):
        """
        Loads a memory object from memory.

        :param page_idx: the index into the page
        :returns: a tuple of the object
        """
        mo = self._storage[page_idx-self._page_addr]
        return self._sinkhole if mo is None else mo


Instruction:
Given the following Python 3 function, write the documentation
def load_slice(self, state, start, end):
        items = [ ]
        if start > self._page_addr + self._page_size or end < self._page_addr:
            l.warning("Calling load_slice on the wrong page.")
            return items

        for addr in range(max(start, self._page_addr), min(end, self._page_addr + self._page_size)):
            i = addr - self._page_addr
            mo = self._storage[i]
            if mo is None:
                mo = self._sinkhole
            if mo is not None and (not items or items[-1][1] is not mo):
                items.append((addr, mo))
        return items

Response: Load the slice of memory objects from the memory.


Instruction:
How would you explain what the following Python 3 function does
def contains_no_backer(self, addr):

        for i, p in self._pages.items():
            if i * self._page_size <= addr < (i + 1) * self._page_size:
                return addr - (i * self._page_size) in p.keys()
        return False

Response: Tests if the address is contained in any page of paged memory without considering memory backers.


Instruction:
Can you implement a function in Python 3 that
gets the set of changed bytes between self and other.

Response:
def __changed_bytes(self, other):
        """
        Gets the set of changed bytes between `self` and `other`.

        :type other:    SimPagedMemory
        :returns:       A set of differing bytes.
        """
        if self._page_size != other._page_size:
            raise SimMemoryError("SimPagedMemory page sizes differ. This is asking for disaster.")

        our_pages = set(self._pages.keys())
        their_pages = set(other._pages.keys())
        their_additions = their_pages - our_pages
        our_additions = our_pages - their_pages
        common_pages = our_pages & their_pages

        candidates = set()
        for p in their_additions:
            candidates.update(other._pages[p].keys())
        for p in our_additions:
            candidates.update(self._pages[p].keys())

        for p in common_pages:
            our_page = self._pages[p]
            their_page = other._pages[p]

            if our_page is their_page:
                continue

            our_keys = set(our_page.keys())
            their_keys = set(their_page.keys())
            changes = (our_keys - their_keys) | (their_keys - our_keys) | {
                i for i in (our_keys & their_keys) if our_page.load_mo(self.state, i) is not their_page.load_mo(self.state, i)
            }
            candidates.update(changes)

        #both_changed = our_changes & their_changes
        #ours_changed_only = our_changes - both_changed
        #theirs_changed_only = their_changes - both_changed
        #both_deleted = their_deletions & our_deletions
        #ours_deleted_only = our_deletions - both_deleted
        #theirs_deleted_only = their_deletions - both_deleted

        differences = set()
        for c in candidates:
            if c not in self and c in other:
                differences.add(c)
            elif c in self and c not in other:
                differences.add(c)
            else:
                if type(self[c]) is not SimMemoryObject:
                    self[c] = SimMemoryObject(self.state.solver.BVV(ord(self[c]), self.byte_width), c, byte_width=self.byte_width)
                if type(other[c]) is not SimMemoryObject:
                    other[c] = SimMemoryObject(self.state.solver.BVV(ord(other[c]), self.byte_width), c, byte_width=self.byte_width)
                if c in self and self[c] != other[c]:
                    # Try to see if the bytes are equal
                    self_byte = self[c].bytes_at(c, 1)
                    other_byte = other[c].bytes_at(c, 1)
                    if self_byte is not other_byte:
                        #l.debug("%s: offset %x, two different bytes %s %s from %s %s", self.id, c,
                        #        self_byte, other_byte,
                        #        self[c].object.model, other[c].object.model)
                        differences.add(c)
                else:
                    # this means the byte is in neither memory
                    pass

        return differences