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//! A driver concretely executes a Falcon IL programs.
use crate::architecture::Architecture;
use crate::executor::successor::*;
use crate::executor::State;
use crate::il;
use crate::Error;
use crate::RC;
/// A driver for a concrete executor over Falcon IL.
#[derive(Debug, Clone)]
pub struct Driver {
program: RC<il::Program>,
location: il::ProgramLocation,
state: State,
architecture: RC<dyn Architecture>,
}
impl Driver {
/// Create a new driver for concrete execution over Falcon IL.
pub fn new(
program: RC<il::Program>,
location: il::ProgramLocation,
state: State,
architecture: RC<dyn Architecture>,
) -> Driver {
Driver {
program,
location,
state,
architecture,
}
}
/// Step forward over Falcon IL.
pub fn step(self) -> Result<Driver, Error> {
let location = self.location.apply(&self.program)?;
match *location.function_location() {
il::RefFunctionLocation::Instruction(_, instruction) => {
let successor = self.state.execute(instruction.operation())?;
match successor.type_().clone() {
SuccessorType::FallThrough => {
let locations = location.forward()?;
if locations.len() == 1 {
Ok(Driver::new(
self.program.clone(),
locations[0].clone().into(),
successor.into(),
self.architecture,
))
} else {
// every location should be an edge, and only one
// edge should be satisfiable
for location in locations {
if let il::RefFunctionLocation::Edge(edge) =
*location.function_location()
{
if successor
.state()
.symbolize_and_eval(
edge.condition()
.ok_or("Failed to get edge condition")?,
)?
.is_one()
{
return Ok(Driver::new(
self.program.clone(),
location.clone().into(),
successor.into(),
self.architecture,
));
}
}
}
Err(Error::ExecutorNoValidLocation)
}
}
SuccessorType::Branch(address) => {
match il::RefProgramLocation::from_address(&self.program, address) {
Some(location) => Ok(Driver::new(
self.program.clone(),
location.into(),
successor.into(),
self.architecture,
)),
None => {
let state: State = successor.into();
let function = self
.architecture
.translator()
.translate_function(state.memory(), address)
.map_err(|e| Error::ExecutorLiftFail(address, Box::new(e)))?;
let mut program = self.program.clone();
RC::make_mut(&mut program).add_function(function);
let location: il::ProgramLocation =
il::RefProgramLocation::from_address(&program, address)
.ok_or("Failed to get location for newly lifted function")?
.into();
Ok(Driver::new(program, location, state, self.architecture))
}
}
}
SuccessorType::Intrinsic(ref intrinsic) => Err(Error::UnhandledIntrinsic(
intrinsic.instruction_str().to_string(),
)),
}
}
il::RefFunctionLocation::Edge(_) => {
let locations = location.forward()?;
Ok(Driver::new(
self.program.clone(),
locations[0].clone().into(),
self.state,
self.architecture,
))
}
il::RefFunctionLocation::EmptyBlock(_) => {
let locations = location.forward()?;
if locations.len() == 1 {
return Ok(Driver::new(
self.program.clone(),
locations[0].clone().into(),
self.state,
self.architecture,
));
} else {
for location in locations {
if let il::RefFunctionLocation::Edge(edge) = *location.function_location() {
if self
.state
.symbolize_and_eval(
edge.condition().ok_or(Error::ExecutorNoEdgeCondition)?,
)?
.is_one()
{
return Ok(Driver::new(
self.program.clone(),
location.clone().into(),
self.state,
self.architecture,
));
}
}
}
}
Err(Error::ExecutorNoValidLocation)
}
}
}
/// Retrieve the Falcon IL program associated with this driver.
pub fn program(&self) -> &il::Program {
&self.program
}
/// If this driver is sitting on an instruction with an address, return
/// that address.
pub fn address(&self) -> Option<u64> {
self.location
.apply(&self.program)
.expect("Failed to apply program location")
.address()
}
/// Retrieve the `il::ProgramLocation` associated with this driver.
pub fn location(&self) -> &il::ProgramLocation {
&self.location
}
/// Retrieve the concrete `State` associated with this driver.
pub fn state(&self) -> &State {
&self.state
}
/// Retrieve a mutable reference to the `State` associated with this driver.
pub fn state_mut(&mut self) -> &mut State {
&mut self.state
}
}