rapx/analysis/safedrop/safedrop.rs
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use rustc_data_structures::fx::FxHashSet;
use rustc_middle::mir::Operand::{Constant, Copy, Move};
use rustc_middle::mir::{Operand, Place, TerminatorKind};
use rustc_middle::ty::{TyCtxt, TyKind};
use std::collections::{HashMap, HashSet};
use crate::analysis::core::alias::FnMap;
use crate::analysis::safedrop::SafeDropGraph;
use crate::rap_error;
pub const VISIT_LIMIT: usize = 1000;
impl<'tcx> SafeDropGraph<'tcx> {
// analyze the drop statement and update the liveness for nodes.
pub fn drop_check(&mut self, bb_index: usize, tcx: TyCtxt<'tcx>) {
let cur_block = self.blocks[bb_index].clone();
for drop in cur_block.drops {
match drop.kind {
TerminatorKind::Drop {
ref place,
target: _,
unwind: _,
replace: _,
} => {
if !self.drop_heap_item_check(place, tcx) {
continue;
}
let birth = self.scc_indices[bb_index];
let drop_local = self.projection(tcx, false, place.clone());
let info = drop.source_info.clone();
self.dead_node(drop_local, birth, &info, false);
}
TerminatorKind::Call {
func: _, ref args, ..
} => {
if args.len() > 0 {
let birth = self.scc_indices[bb_index];
let place = match args[0].node {
Operand::Copy(place) => place,
Operand::Move(place) => place,
_ => {
rap_error!("Constant operand exists: {:?}", args[0]);
return;
}
};
let drop_local = self.projection(tcx, false, place.clone());
let info = drop.source_info.clone();
self.dead_node(drop_local, birth, &info, false);
}
}
_ => {}
}
}
}
pub fn drop_heap_item_check(&self, place: &Place<'tcx>, tcx: TyCtxt<'tcx>) -> bool {
let place_ty = place.ty(&tcx.optimized_mir(self.def_id).local_decls, tcx);
match place_ty.ty.kind() {
TyKind::Adt(adtdef, ..) => match self.adt_owner.get(&adtdef.did()) {
None => true,
Some(owenr_unit) => {
let idx = match place_ty.variant_index {
Some(vdx) => vdx.index(),
None => 0,
};
if owenr_unit[idx].0.is_owned() || owenr_unit[idx].1.contains(&true) {
true
} else {
false
}
}
},
_ => true,
}
}
pub fn split_check(&mut self, bb_index: usize, tcx: TyCtxt<'tcx>, fn_map: &FnMap) {
/* duplicate the status before visiting a path; */
let backup_values = self.values.clone(); // duplicate the status when visiting different paths;
let backup_constant = self.constant.clone();
let backup_alias_set = self.alias_set.clone();
let backup_dead = self.dead_record.clone();
self.check(bb_index, tcx, fn_map);
/* restore after visit */
self.values = backup_values;
self.constant = backup_constant;
self.alias_set = backup_alias_set;
self.dead_record = backup_dead;
}
pub fn split_check_with_cond(
&mut self,
bb_index: usize,
path_discr_id: usize,
path_discr_val: usize,
tcx: TyCtxt<'tcx>,
fn_map: &FnMap,
) {
/* duplicate the status before visiting a path; */
let backup_values = self.values.clone(); // duplicate the status when visiting different paths;
let backup_constant = self.constant.clone();
let backup_alias_set = self.alias_set.clone();
let backup_dead = self.dead_record.clone();
/* add control-sensitive indicator to the path status */
self.constant.insert(path_discr_id, path_discr_val);
self.check(bb_index, tcx, fn_map);
/* restore after visit */
self.values = backup_values;
self.constant = backup_constant;
self.alias_set = backup_alias_set;
self.dead_record = backup_dead;
}
// the core function of the safedrop.
pub fn check(&mut self, bb_index: usize, tcx: TyCtxt<'tcx>, fn_map: &FnMap) {
self.visit_times += 1;
if self.visit_times > VISIT_LIMIT {
return;
}
let cur_block = self.blocks[self.scc_indices[bb_index]].clone();
self.alias_bb(self.scc_indices[bb_index], tcx);
self.alias_bbcall(self.scc_indices[bb_index], tcx, fn_map);
self.drop_check(self.scc_indices[bb_index], tcx);
if self.child_scc.get(&self.scc_indices[bb_index]).is_some() {
let init_index = self.scc_indices[bb_index];
let (init_block, cur_targets, scc_block_set) =
self.child_scc.get(&init_index).unwrap().clone();
for enum_index in cur_targets.all_targets() {
let backup_values = self.values.clone();
let backup_constant = self.constant.clone();
let mut block_node = if bb_index == init_index {
init_block.clone()
} else {
self.blocks[bb_index].clone()
};
if !block_node.switch_stmts.is_empty() {
let TerminatorKind::SwitchInt { targets, .. } =
block_node.switch_stmts[0].kind.clone()
else {
unreachable!();
};
if cur_targets == targets {
block_node.next = FxHashSet::default();
block_node.next.insert(enum_index.index());
}
}
let mut work_list = Vec::new();
let mut work_set = FxHashSet::<usize>::default();
work_list.push(bb_index);
work_set.insert(bb_index);
while !work_list.is_empty() {
let current_node = work_list.pop().unwrap();
block_node.scc_sub_blocks.push(current_node);
let real_node = if current_node != init_index {
self.blocks[current_node].clone()
} else {
init_block.clone()
};
if real_node.switch_stmts.is_empty() {
for next in &real_node.next {
block_node.next.insert(*next);
}
} else {
let TerminatorKind::SwitchInt { ref targets, .. } =
real_node.switch_stmts[0].kind
else {
unreachable!();
};
if cur_targets == *targets {
block_node.next.insert(enum_index.index());
} else {
for next in &real_node.next {
block_node.next.insert(*next);
}
}
}
if real_node.switch_stmts.is_empty() {
for next in &real_node.next {
if scc_block_set.contains(next) && !work_set.contains(next) {
work_set.insert(*next);
work_list.push(*next);
}
}
} else {
let TerminatorKind::SwitchInt { ref targets, .. } =
real_node.switch_stmts[0].kind
else {
unreachable!();
};
if cur_targets == *targets {
let next_index = enum_index.index();
if scc_block_set.contains(&next_index)
&& !work_set.contains(&next_index)
{
work_set.insert(next_index);
work_list.push(next_index);
}
} else {
for next in &real_node.next {
if scc_block_set.contains(next) && !work_set.contains(next) {
work_set.insert(*next);
work_list.push(*next);
}
}
}
}
}
/* remove next nodes which are already in the current SCC */
let mut to_remove = Vec::new();
for i in block_node.next.iter() {
if self.scc_indices[*i] == init_index {
to_remove.push(*i);
}
}
for i in to_remove {
block_node.next.remove(&i);
}
for i in block_node.scc_sub_blocks.clone() {
self.alias_bb(i, tcx);
self.alias_bbcall(i, tcx, fn_map);
self.drop_check(i, tcx);
}
/* Reach a leaf node, check bugs */
match block_node.next.len() {
0 => {
// check the bugs.
if Self::should_check(self.def_id) {
self.dp_check(&cur_block);
}
return;
}
_ => {
/*
* Equivalent to self.check(cur_block.next[0]..);
* We cannot use [0] for FxHashSet.
*/
for next in block_node.next {
self.check(next, tcx, fn_map);
}
}
}
self.values = backup_values;
self.constant = backup_constant;
}
return;
}
let mut order = vec![];
order.push(vec![]);
/* Handle cases if the current block is a merged scc block with sub block */
if !cur_block.scc_sub_blocks.is_empty() {
match std::env::var_os("FAST_ALIAS") {
Some(_) => {
order.push(cur_block.scc_sub_blocks.clone());
}
_ => {
self.calculate_scc_order(
&mut cur_block.scc_sub_blocks.clone(),
&mut vec![],
&mut order,
&mut HashMap::new(),
bb_index,
bb_index,
&mut HashSet::new(),
);
}
}
}
let backup_values = self.values.clone(); // duplicate the status when visiting different paths;
let backup_constant = self.constant.clone();
let backup_alias_set = self.alias_set.clone();
for scc_each in order {
self.alias_set = backup_alias_set.clone();
self.values = backup_values.clone();
self.constant = backup_constant.clone();
if !scc_each.is_empty() {
for idx in scc_each {
self.alias_bb(idx, tcx);
self.alias_bbcall(idx, tcx, fn_map);
}
}
let cur_block = cur_block.clone();
/* Reach a leaf node, check bugs */
match cur_block.next.len() {
0 => {
if Self::should_check(self.def_id) {
self.dp_check(&cur_block);
}
return;
}
1 => {
/*
* Equivalent to self.check(cur_block.next[0]..);
* We cannot use [0] for FxHashSet.
*/
for next in cur_block.next {
self.check(next, tcx, fn_map);
}
return;
}
_ => { // multiple blocks
}
}
/* Begin: handle the SwitchInt statement. */
let mut single_target = false;
let mut sw_val = 0;
let mut sw_target = 0; // Single target
let mut path_discr_id = 0; // To avoid analyzing paths that cannot be reached with one enum type.
let mut sw_targets = None; // Multiple targets of SwitchInt
if !cur_block.switch_stmts.is_empty() && cur_block.scc_sub_blocks.is_empty() {
if let TerminatorKind::SwitchInt {
ref discr,
ref targets,
} = cur_block.switch_stmts[0].clone().kind
{
match discr {
Copy(p) | Move(p) => {
let place = self.projection(tcx, false, *p);
if let Some(father) = self.disc_map.get(&self.values[place].local) {
if let Some(constant) = self.constant.get(father) {
if *constant != usize::MAX {
single_target = true;
sw_val = *constant;
}
}
if self.values[place].local == place {
path_discr_id = *father;
sw_targets = Some(targets.clone());
}
}
}
Constant(c) => {
single_target = true;
let param_env = self.tcx.param_env(self.def_id);
if let Some(val) = c.const_.try_eval_target_usize(self.tcx, param_env) {
sw_val = val as usize;
}
}
}
if single_target {
/* Find the target based on the value;
* Since sw_val is a const, only one target is reachable.
* Filed 0 is the value; field 1 is the real target.
*/
for iter in targets.iter() {
if iter.0 as usize == sw_val {
sw_target = iter.1.as_usize();
break;
}
}
/* No target found, choose the default target.
* The default targets is not included within the iterator.
* We can only obtain the default target based on the last item of all_targets().
*/
if sw_target == 0 {
let all_target = targets.all_targets();
sw_target = all_target[all_target.len() - 1].as_usize();
}
}
}
}
/* End: finish handling SwitchInt */
// fixed path since a constant switchInt value
if single_target {
self.check(sw_target, tcx, fn_map);
} else {
// Other cases in switchInt terminators
if let Some(targets) = sw_targets {
for iter in targets.iter() {
if self.visit_times > VISIT_LIMIT {
continue;
}
let next_index = iter.1.as_usize();
let path_discr_val = iter.0 as usize;
self.split_check_with_cond(
next_index,
path_discr_id,
path_discr_val,
tcx,
fn_map,
);
}
let all_targets = targets.all_targets();
let next_index = all_targets[all_targets.len() - 1].as_usize();
let path_discr_val = usize::MAX; // to indicate the default path;
self.split_check_with_cond(
next_index,
path_discr_id,
path_discr_val,
tcx,
fn_map,
);
} else {
for i in cur_block.next {
if self.visit_times > VISIT_LIMIT {
continue;
}
let next_index = i;
self.split_check(next_index, tcx, fn_map);
}
}
}
}
}
pub fn calculate_scc_order(
&mut self,
scc: &Vec<usize>,
path: &mut Vec<usize>,
ans: &mut Vec<Vec<usize>>,
disc_map: &mut HashMap<usize, usize>,
idx: usize,
root: usize,
visit: &mut HashSet<usize>,
) {
if idx == root && !path.is_empty() {
ans.push(path.clone());
return;
}
visit.insert(idx);
let term = &self.terms[idx].clone();
match term {
TerminatorKind::SwitchInt {
ref discr,
ref targets,
} => match discr {
Copy(p) | Move(p) => {
let place = self.projection(self.tcx, false, *p);
if let Some(father) = self.disc_map.get(&self.values[place].local) {
let father = *father;
if let Some(constant) = disc_map.get(&father) {
let constant = *constant;
for t in targets.iter() {
if t.0 as usize == constant {
let target = t.1.as_usize();
if path.contains(&target) {
continue;
}
path.push(target);
self.calculate_scc_order(
scc, path, ans, disc_map, target, root, visit,
);
path.pop();
}
}
} else {
for t in targets.iter() {
let constant = t.0 as usize;
let target = t.1.as_usize();
if path.contains(&target) {
continue;
}
path.push(target);
disc_map.insert(father, constant);
self.calculate_scc_order(
scc, path, ans, disc_map, target, root, visit,
);
disc_map.remove(&father);
path.pop();
}
}
} else {
if let Some(constant) = disc_map.get(&place) {
let constant = *constant;
for t in targets.iter() {
if t.0 as usize == constant {
let target = t.1.as_usize();
if path.contains(&target) {
continue;
}
path.push(target);
self.calculate_scc_order(
scc, path, ans, disc_map, target, root, visit,
);
path.pop();
}
}
} else {
for t in targets.iter() {
let constant = t.0 as usize;
let target = t.1.as_usize();
if path.contains(&target) {
continue;
}
path.push(target);
disc_map.insert(place, constant);
self.calculate_scc_order(
scc, path, ans, disc_map, target, root, visit,
);
disc_map.remove(&place);
path.pop();
}
let constant = targets.iter().len();
let target = targets.otherwise().as_usize();
if !path.contains(&target) {
path.push(target);
disc_map.insert(place, constant);
self.calculate_scc_order(
scc, path, ans, disc_map, target, root, visit,
);
disc_map.remove(&place);
path.pop();
}
}
}
}
_ => {}
},
_ => {
for bidx in self.blocks[idx].next.clone() {
if !scc.contains(&bidx) && bidx != root {
continue;
}
if bidx != root {
path.push(bidx);
self.calculate_scc_order(scc, path, ans, disc_map, bidx, root, visit);
path.pop();
} else {
self.calculate_scc_order(scc, path, ans, disc_map, bidx, root, visit);
}
}
}
}
visit.remove(&idx);
}
}