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use hir::def_id::DefId;
use std::cell::RefCell;
use std::env;
use super::DepNode;
use super::thread::DepMessage;
use super::debug::EdgeFilter;
pub struct ShadowGraph {
stack: RefCell<Vec<Option<DepNode<DefId>>>>,
forbidden_edge: Option<EdgeFilter>,
}
const ENABLED: bool = cfg!(debug_assertions);
impl ShadowGraph {
pub fn new() -> Self {
let forbidden_edge = if !ENABLED {
None
} else {
match env::var("RUST_FORBID_DEP_GRAPH_EDGE") {
Ok(s) => {
match EdgeFilter::new(&s) {
Ok(f) => Some(f),
Err(err) => bug!("RUST_FORBID_DEP_GRAPH_EDGE invalid: {}", err),
}
}
Err(_) => None,
}
};
ShadowGraph {
stack: RefCell::new(vec![]),
forbidden_edge: forbidden_edge,
}
}
#[inline]
pub fn enabled(&self) -> bool {
ENABLED
}
pub fn enqueue(&self, message: &DepMessage) {
if ENABLED {
if self.stack.try_borrow().is_err() {
return;
}
let mut stack = self.stack.borrow_mut();
match *message {
DepMessage::Read(ref n) => self.check_edge(Some(Some(n)), top(&stack)),
DepMessage::Write(ref n) => self.check_edge(top(&stack), Some(Some(n))),
DepMessage::PushTask(ref n) => stack.push(Some(n.clone())),
DepMessage::PushIgnore => stack.push(None),
DepMessage::PopTask(ref n) => {
match stack.pop() {
Some(Some(m)) => {
if *n != m {
bug!("stack mismatch: found {:?} expected {:?}", m, n)
}
}
Some(None) => bug!("stack mismatch: found Ignore expected {:?}", n),
None => bug!("stack mismatch: found empty stack, expected {:?}", n),
}
}
DepMessage::PopIgnore => {
match stack.pop() {
Some(Some(m)) => bug!("stack mismatch: found {:?} expected ignore", m),
Some(None) => (),
None => bug!("stack mismatch: found empty stack, expected ignore"),
}
}
DepMessage::Query => (),
}
}
}
fn check_edge(&self,
source: Option<Option<&DepNode<DefId>>>,
target: Option<Option<&DepNode<DefId>>>) {
assert!(ENABLED);
match (source, target) {
(None, None) => unreachable!(),
(None, Some(n)) | (Some(n), None) => bug!("read/write of {:?} but no current task", n),
(Some(None), _) | (_, Some(None)) => (),
(Some(Some(source)), Some(Some(target))) => {
if let Some(ref forbidden_edge) = self.forbidden_edge {
if forbidden_edge.test(source, target) {
bug!("forbidden edge {:?} -> {:?} created", source, target)
}
}
}
}
}
}
fn top<'s>(stack: &'s Vec<Option<DepNode<DefId>>>) -> Option<Option<&'s DepNode<DefId>>> {
stack.last()
.map(|n: &'s Option<DepNode<DefId>>| -> Option<&'s DepNode<DefId>> {
n.as_ref()
})
}