1 use crate::ty::{self, TyCtxt};
2 use parking_lot::{Condvar, Mutex};
3 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
4 use rustc_data_structures::profiling::QueryInvocationId;
5 use rustc_data_structures::sharded::{self, Sharded};
6 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
7 use rustc_data_structures::sync::{AtomicU32, AtomicU64, Lock, Lrc, Ordering};
8 use rustc_errors::Diagnostic;
9 use rustc_hir::def_id::DefId;
10 use rustc_index::vec::{Idx, IndexVec};
11 use smallvec::SmallVec;
12 use std::collections::hash_map::Entry;
16 use std::sync::atomic::Ordering::Relaxed;
18 use crate::ich::{Fingerprint, StableHashingContext, StableHashingContextProvider};
20 use super::debug::EdgeFilter;
21 use super::dep_node::{DepKind, DepNode, WorkProductId};
22 use super::prev::PreviousDepGraph;
23 use super::query::DepGraphQuery;
24 use super::safe::DepGraphSafe;
25 use super::serialized::{SerializedDepGraph, SerializedDepNodeIndex};
29 data: Option<Lrc<DepGraphData>>,
31 /// This field is used for assigning DepNodeIndices when running in
32 /// non-incremental mode. Even in non-incremental mode we make sure that
33 /// each task has a `DepNodeIndex` that uniquely identifies it. This unique
34 /// ID is used for self-profiling.
35 virtual_dep_node_index: Lrc<AtomicU32>,
38 rustc_index::newtype_index! {
39 pub struct DepNodeIndex { .. }
43 pub const INVALID: DepNodeIndex = DepNodeIndex::MAX;
46 impl std::convert::From<DepNodeIndex> for QueryInvocationId {
48 fn from(dep_node_index: DepNodeIndex) -> Self {
49 QueryInvocationId(dep_node_index.as_u32())
54 pub enum DepNodeColor {
60 pub fn is_green(self) -> bool {
62 DepNodeColor::Red => false,
63 DepNodeColor::Green(_) => true,
69 /// The new encoding of the dependency graph, optimized for red/green
70 /// tracking. The `current` field is the dependency graph of only the
71 /// current compilation session: We don't merge the previous dep-graph into
72 /// current one anymore.
73 current: CurrentDepGraph,
75 /// The dep-graph from the previous compilation session. It contains all
76 /// nodes and edges as well as all fingerprints of nodes that have them.
77 previous: PreviousDepGraph,
79 colors: DepNodeColorMap,
81 /// A set of loaded diagnostics that is in the progress of being emitted.
82 emitting_diagnostics: Mutex<FxHashSet<DepNodeIndex>>,
84 /// Used to wait for diagnostics to be emitted.
85 emitting_diagnostics_cond_var: Condvar,
87 /// When we load, there may be `.o` files, cached MIR, or other such
88 /// things available to us. If we find that they are not dirty, we
89 /// load the path to the file storing those work-products here into
90 /// this map. We can later look for and extract that data.
91 previous_work_products: FxHashMap<WorkProductId, WorkProduct>,
93 dep_node_debug: Lock<FxHashMap<DepNode, String>>,
96 pub fn hash_result<R>(hcx: &mut StableHashingContext<'_>, result: &R) -> Option<Fingerprint>
98 R: for<'a> HashStable<StableHashingContext<'a>>,
100 let mut stable_hasher = StableHasher::new();
101 result.hash_stable(hcx, &mut stable_hasher);
103 Some(stable_hasher.finish())
108 prev_graph: PreviousDepGraph,
109 prev_work_products: FxHashMap<WorkProductId, WorkProduct>,
111 let prev_graph_node_count = prev_graph.node_count();
114 data: Some(Lrc::new(DepGraphData {
115 previous_work_products: prev_work_products,
116 dep_node_debug: Default::default(),
117 current: CurrentDepGraph::new(prev_graph_node_count),
118 emitting_diagnostics: Default::default(),
119 emitting_diagnostics_cond_var: Condvar::new(),
120 previous: prev_graph,
121 colors: DepNodeColorMap::new(prev_graph_node_count),
123 virtual_dep_node_index: Lrc::new(AtomicU32::new(0)),
127 pub fn new_disabled() -> DepGraph {
128 DepGraph { data: None, virtual_dep_node_index: Lrc::new(AtomicU32::new(0)) }
131 /// Returns `true` if we are actually building the full dep-graph, and `false` otherwise.
133 pub fn is_fully_enabled(&self) -> bool {
137 pub fn query(&self) -> DepGraphQuery {
138 let data = self.data.as_ref().unwrap().current.data.lock();
139 let nodes: Vec<_> = data.iter().map(|n| n.node).collect();
140 let mut edges = Vec::new();
141 for (from, edge_targets) in data.iter().map(|d| (d.node, &d.edges)) {
142 for &edge_target in edge_targets.iter() {
143 let to = data[edge_target].node;
144 edges.push((from, to));
148 DepGraphQuery::new(&nodes[..], &edges[..])
151 pub fn assert_ignored(&self) {
152 if let Some(..) = self.data {
153 ty::tls::with_context_opt(|icx| {
154 let icx = if let Some(icx) = icx { icx } else { return };
155 assert!(icx.task_deps.is_none(), "expected no task dependency tracking");
160 pub fn with_ignore<OP, R>(&self, op: OP) -> R
164 ty::tls::with_context(|icx| {
165 let icx = ty::tls::ImplicitCtxt { task_deps: None, ..icx.clone() };
167 ty::tls::enter_context(&icx, |_| op())
171 /// Starts a new dep-graph task. Dep-graph tasks are specified
172 /// using a free function (`task`) and **not** a closure -- this
173 /// is intentional because we want to exercise tight control over
174 /// what state they have access to. In particular, we want to
175 /// prevent implicit 'leaks' of tracked state into the task (which
176 /// could then be read without generating correct edges in the
177 /// dep-graph -- see the [rustc guide] for more details on
178 /// the dep-graph). To this end, the task function gets exactly two
179 /// pieces of state: the context `cx` and an argument `arg`. Both
180 /// of these bits of state must be of some type that implements
181 /// `DepGraphSafe` and hence does not leak.
183 /// The choice of two arguments is not fundamental. One argument
184 /// would work just as well, since multiple values can be
185 /// collected using tuples. However, using two arguments works out
186 /// to be quite convenient, since it is common to need a context
187 /// (`cx`) and some argument (e.g., a `DefId` identifying what
188 /// item to process).
190 /// For cases where you need some other number of arguments:
192 /// - If you only need one argument, just use `()` for the `arg`
194 /// - If you need 3+ arguments, use a tuple for the
197 /// [rustc guide]: https://rust-lang.github.io/rustc-guide/incremental-compilation.html
198 pub fn with_task<'a, C, A, R>(
204 hash_result: impl FnOnce(&mut StableHashingContext<'_>, &R) -> Option<Fingerprint>,
205 ) -> (R, DepNodeIndex)
207 C: DepGraphSafe + StableHashingContextProvider<'a>,
217 #[cfg(debug_assertions)]
219 reads: SmallVec::new(),
220 read_set: Default::default(),
223 |data, key, fingerprint, task| data.complete_task(key, task.unwrap(), fingerprint),
228 /// Creates a new dep-graph input with value `input`
229 pub fn input_task<'a, C, R>(&self, key: DepNode, cx: C, input: R) -> (R, DepNodeIndex)
231 C: DepGraphSafe + StableHashingContextProvider<'a>,
232 R: for<'b> HashStable<StableHashingContext<'b>>,
234 fn identity_fn<C, A>(_: C, arg: A) -> A {
245 |data, key, fingerprint, _| data.alloc_node(key, SmallVec::new(), fingerprint),
250 fn with_task_impl<'a, C, A, R>(
257 create_task: fn(DepNode) -> Option<TaskDeps>,
258 finish_task_and_alloc_depnode: fn(
264 hash_result: impl FnOnce(&mut StableHashingContext<'_>, &R) -> Option<Fingerprint>,
265 ) -> (R, DepNodeIndex)
267 C: DepGraphSafe + StableHashingContextProvider<'a>,
269 if let Some(ref data) = self.data {
270 let task_deps = create_task(key).map(|deps| Lock::new(deps));
272 // In incremental mode, hash the result of the task. We don't
273 // do anything with the hash yet, but we are computing it
275 // - we make sure that the infrastructure works and
276 // - we can get an idea of the runtime cost.
277 let mut hcx = cx.get_stable_hashing_context();
279 let result = if no_tcx {
282 ty::tls::with_context(|icx| {
284 ty::tls::ImplicitCtxt { task_deps: task_deps.as_ref(), ..icx.clone() };
286 ty::tls::enter_context(&icx, |_| task(cx, arg))
290 let current_fingerprint = hash_result(&mut hcx, &result);
292 let dep_node_index = finish_task_and_alloc_depnode(
295 current_fingerprint.unwrap_or(Fingerprint::ZERO),
296 task_deps.map(|lock| lock.into_inner()),
299 let print_status = cfg!(debug_assertions) && hcx.sess().opts.debugging_opts.dep_tasks;
301 // Determine the color of the new DepNode.
302 if let Some(prev_index) = data.previous.node_to_index_opt(&key) {
303 let prev_fingerprint = data.previous.fingerprint_by_index(prev_index);
305 let color = if let Some(current_fingerprint) = current_fingerprint {
306 if current_fingerprint == prev_fingerprint {
308 eprintln!("[task::green] {:?}", key);
310 DepNodeColor::Green(dep_node_index)
313 eprintln!("[task::red] {:?}", key);
319 eprintln!("[task::unknown] {:?}", key);
321 // Mark the node as Red if we can't hash the result
326 data.colors.get(prev_index).is_none(),
327 "DepGraph::with_task() - Duplicate DepNodeColor \
332 data.colors.insert(prev_index, color);
335 eprintln!("[task::new] {:?}", key);
339 (result, dep_node_index)
341 (task(cx, arg), self.next_virtual_depnode_index())
345 /// Executes something within an "anonymous" task, that is, a task the
346 /// `DepNode` of which is determined by the list of inputs it read from.
347 pub fn with_anon_task<OP, R>(&self, dep_kind: DepKind, op: OP) -> (R, DepNodeIndex)
351 if let Some(ref data) = self.data {
352 let (result, task_deps) = ty::tls::with_context(|icx| {
353 let task_deps = Lock::new(TaskDeps {
354 #[cfg(debug_assertions)]
356 reads: SmallVec::new(),
357 read_set: Default::default(),
361 let icx = ty::tls::ImplicitCtxt { task_deps: Some(&task_deps), ..icx.clone() };
363 ty::tls::enter_context(&icx, |_| op())
366 (r, task_deps.into_inner())
368 let dep_node_index = data.current.complete_anon_task(dep_kind, task_deps);
369 (result, dep_node_index)
371 (op(), self.next_virtual_depnode_index())
375 /// Executes something within an "eval-always" task which is a task
376 /// that runs whenever anything changes.
377 pub fn with_eval_always_task<'a, C, A, R>(
383 hash_result: impl FnOnce(&mut StableHashingContext<'_>, &R) -> Option<Fingerprint>,
384 ) -> (R, DepNodeIndex)
386 C: DepGraphSafe + StableHashingContextProvider<'a>,
395 |data, key, fingerprint, _| data.alloc_node(key, smallvec![], fingerprint),
401 pub fn read(&self, v: DepNode) {
402 if let Some(ref data) = self.data {
403 let map = data.current.node_to_node_index.get_shard_by_value(&v).lock();
404 if let Some(dep_node_index) = map.get(&v).copied() {
406 data.read_index(dep_node_index);
408 bug!("DepKind {:?} should be pre-allocated but isn't.", v.kind)
414 pub fn read_index(&self, dep_node_index: DepNodeIndex) {
415 if let Some(ref data) = self.data {
416 data.read_index(dep_node_index);
421 pub fn dep_node_index_of(&self, dep_node: &DepNode) -> DepNodeIndex {
427 .get_shard_by_value(dep_node)
435 pub fn dep_node_exists(&self, dep_node: &DepNode) -> bool {
436 if let Some(ref data) = self.data {
439 .get_shard_by_value(&dep_node)
441 .contains_key(dep_node)
448 pub fn fingerprint_of(&self, dep_node_index: DepNodeIndex) -> Fingerprint {
449 let data = self.data.as_ref().expect("dep graph enabled").current.data.lock();
450 data[dep_node_index].fingerprint
453 pub fn prev_fingerprint_of(&self, dep_node: &DepNode) -> Option<Fingerprint> {
454 self.data.as_ref().unwrap().previous.fingerprint_of(dep_node)
458 pub fn prev_dep_node_index_of(&self, dep_node: &DepNode) -> SerializedDepNodeIndex {
459 self.data.as_ref().unwrap().previous.node_to_index(dep_node)
462 /// Checks whether a previous work product exists for `v` and, if
463 /// so, return the path that leads to it. Used to skip doing work.
464 pub fn previous_work_product(&self, v: &WorkProductId) -> Option<WorkProduct> {
465 self.data.as_ref().and_then(|data| data.previous_work_products.get(v).cloned())
468 /// Access the map of work-products created during the cached run. Only
469 /// used during saving of the dep-graph.
470 pub fn previous_work_products(&self) -> &FxHashMap<WorkProductId, WorkProduct> {
471 &self.data.as_ref().unwrap().previous_work_products
475 pub fn register_dep_node_debug_str<F>(&self, dep_node: DepNode, debug_str_gen: F)
477 F: FnOnce() -> String,
479 let dep_node_debug = &self.data.as_ref().unwrap().dep_node_debug;
481 if dep_node_debug.borrow().contains_key(&dep_node) {
484 let debug_str = debug_str_gen();
485 dep_node_debug.borrow_mut().insert(dep_node, debug_str);
488 pub(super) fn dep_node_debug_str(&self, dep_node: DepNode) -> Option<String> {
489 self.data.as_ref()?.dep_node_debug.borrow().get(&dep_node).cloned()
492 pub fn edge_deduplication_data(&self) -> Option<(u64, u64)> {
493 if cfg!(debug_assertions) {
494 let current_dep_graph = &self.data.as_ref().unwrap().current;
497 current_dep_graph.total_read_count.load(Relaxed),
498 current_dep_graph.total_duplicate_read_count.load(Relaxed),
505 pub fn serialize(&self) -> SerializedDepGraph {
506 let data = self.data.as_ref().unwrap().current.data.lock();
508 let fingerprints: IndexVec<SerializedDepNodeIndex, _> =
509 data.iter().map(|d| d.fingerprint).collect();
510 let nodes: IndexVec<SerializedDepNodeIndex, _> = data.iter().map(|d| d.node).collect();
512 let total_edge_count: usize = data.iter().map(|d| d.edges.len()).sum();
514 let mut edge_list_indices = IndexVec::with_capacity(nodes.len());
515 let mut edge_list_data = Vec::with_capacity(total_edge_count);
517 for (current_dep_node_index, edges) in data.iter_enumerated().map(|(i, d)| (i, &d.edges)) {
518 let start = edge_list_data.len() as u32;
519 // This should really just be a memcpy :/
520 edge_list_data.extend(edges.iter().map(|i| SerializedDepNodeIndex::new(i.index())));
521 let end = edge_list_data.len() as u32;
523 debug_assert_eq!(current_dep_node_index.index(), edge_list_indices.len());
524 edge_list_indices.push((start, end));
527 debug_assert!(edge_list_data.len() <= ::std::u32::MAX as usize);
528 debug_assert_eq!(edge_list_data.len(), total_edge_count);
530 SerializedDepGraph { nodes, fingerprints, edge_list_indices, edge_list_data }
533 pub fn node_color(&self, dep_node: &DepNode) -> Option<DepNodeColor> {
534 if let Some(ref data) = self.data {
535 if let Some(prev_index) = data.previous.node_to_index_opt(dep_node) {
536 return data.colors.get(prev_index);
538 // This is a node that did not exist in the previous compilation
539 // session, so we consider it to be red.
540 return Some(DepNodeColor::Red);
547 /// Try to read a node index for the node dep_node.
548 /// A node will have an index, when it's already been marked green, or when we can mark it
549 /// green. This function will mark the current task as a reader of the specified node, when
550 /// a node index can be found for that node.
551 pub fn try_mark_green_and_read(
555 ) -> Option<(SerializedDepNodeIndex, DepNodeIndex)> {
556 self.try_mark_green(tcx, dep_node).map(|(prev_index, dep_node_index)| {
557 debug_assert!(self.is_green(&dep_node));
558 self.read_index(dep_node_index);
559 (prev_index, dep_node_index)
563 pub fn try_mark_green(
567 ) -> Option<(SerializedDepNodeIndex, DepNodeIndex)> {
568 debug_assert!(!dep_node.kind.is_eval_always());
570 // Return None if the dep graph is disabled
571 let data = self.data.as_ref()?;
573 // Return None if the dep node didn't exist in the previous session
574 let prev_index = data.previous.node_to_index_opt(dep_node)?;
576 match data.colors.get(prev_index) {
577 Some(DepNodeColor::Green(dep_node_index)) => Some((prev_index, dep_node_index)),
578 Some(DepNodeColor::Red) => None,
580 // This DepNode and the corresponding query invocation existed
581 // in the previous compilation session too, so we can try to
582 // mark it as green by recursively marking all of its
583 // dependencies green.
584 self.try_mark_previous_green(tcx, data, prev_index, &dep_node)
585 .map(|dep_node_index| (prev_index, dep_node_index))
590 /// Try to mark a dep-node which existed in the previous compilation session as green.
591 fn try_mark_previous_green<'tcx>(
595 prev_dep_node_index: SerializedDepNodeIndex,
597 ) -> Option<DepNodeIndex> {
598 debug!("try_mark_previous_green({:?}) - BEGIN", dep_node);
600 #[cfg(not(parallel_compiler))]
606 .get_shard_by_value(dep_node)
608 .contains_key(dep_node)
610 debug_assert!(data.colors.get(prev_dep_node_index).is_none());
613 // We never try to mark eval_always nodes as green
614 debug_assert!(!dep_node.kind.is_eval_always());
616 debug_assert_eq!(data.previous.index_to_node(prev_dep_node_index), *dep_node);
618 let prev_deps = data.previous.edge_targets_from(prev_dep_node_index);
620 let mut current_deps = SmallVec::new();
622 for &dep_dep_node_index in prev_deps {
623 let dep_dep_node_color = data.colors.get(dep_dep_node_index);
625 match dep_dep_node_color {
626 Some(DepNodeColor::Green(node_index)) => {
627 // This dependency has been marked as green before, we are
628 // still fine and can continue with checking the other
631 "try_mark_previous_green({:?}) --- found dependency {:?} to \
632 be immediately green",
634 data.previous.index_to_node(dep_dep_node_index)
636 current_deps.push(node_index);
638 Some(DepNodeColor::Red) => {
639 // We found a dependency the value of which has changed
640 // compared to the previous compilation session. We cannot
641 // mark the DepNode as green and also don't need to bother
642 // with checking any of the other dependencies.
644 "try_mark_previous_green({:?}) - END - dependency {:?} was \
647 data.previous.index_to_node(dep_dep_node_index)
652 let dep_dep_node = &data.previous.index_to_node(dep_dep_node_index);
654 // We don't know the state of this dependency. If it isn't
655 // an eval_always node, let's try to mark it green recursively.
656 if !dep_dep_node.kind.is_eval_always() {
658 "try_mark_previous_green({:?}) --- state of dependency {:?} \
659 is unknown, trying to mark it green",
660 dep_node, dep_dep_node
663 let node_index = self.try_mark_previous_green(
669 if let Some(node_index) = node_index {
671 "try_mark_previous_green({:?}) --- managed to MARK \
672 dependency {:?} as green",
673 dep_node, dep_dep_node
675 current_deps.push(node_index);
679 match dep_dep_node.kind {
680 DepKind::Hir | DepKind::HirBody | DepKind::CrateMetadata => {
681 if let Some(def_id) = dep_dep_node.extract_def_id(tcx) {
682 if def_id_corresponds_to_hir_dep_node(tcx, def_id) {
683 // The `DefPath` has corresponding node,
684 // and that node should have been marked
685 // either red or green in `data.colors`.
687 "DepNode {:?} should have been \
688 pre-marked as red or green but wasn't.",
692 // This `DefPath` does not have a
693 // corresponding `DepNode` (e.g. a
694 // struct field), and the ` DefPath`
695 // collided with the `DefPath` of a
696 // proper item that existed in the
697 // previous compilation session.
699 // Since the given `DefPath` does not
700 // denote the item that previously
701 // existed, we just fail to mark green.
705 // If the node does not exist anymore, we
706 // just fail to mark green.
711 // For other kinds of nodes it's OK to be
717 // We failed to mark it green, so we try to force the query.
719 "try_mark_previous_green({:?}) --- trying to force \
721 dep_node, dep_dep_node
723 if crate::ty::query::force_from_dep_node(tcx, dep_dep_node) {
724 let dep_dep_node_color = data.colors.get(dep_dep_node_index);
726 match dep_dep_node_color {
727 Some(DepNodeColor::Green(node_index)) => {
729 "try_mark_previous_green({:?}) --- managed to \
730 FORCE dependency {:?} to green",
731 dep_node, dep_dep_node
733 current_deps.push(node_index);
735 Some(DepNodeColor::Red) => {
737 "try_mark_previous_green({:?}) - END - \
738 dependency {:?} was red after forcing",
739 dep_node, dep_dep_node
744 if !tcx.sess.has_errors_or_delayed_span_bugs() {
746 "try_mark_previous_green() - Forcing the DepNode \
747 should have set its color"
750 // If the query we just forced has resulted in
751 // some kind of compilation error, we cannot rely on
752 // the dep-node color having been properly updated.
753 // This means that the query system has reached an
754 // invalid state. We let the compiler continue (by
755 // returning `None`) so it can emit error messages
756 // and wind down, but rely on the fact that this
757 // invalid state will not be persisted to the
758 // incremental compilation cache because of
759 // compilation errors being present.
761 "try_mark_previous_green({:?}) - END - \
762 dependency {:?} resulted in compilation error",
763 dep_node, dep_dep_node
770 // The DepNode could not be forced.
772 "try_mark_previous_green({:?}) - END - dependency {:?} \
773 could not be forced",
774 dep_node, dep_dep_node
782 // If we got here without hitting a `return` that means that all
783 // dependencies of this DepNode could be marked as green. Therefore we
784 // can also mark this DepNode as green.
786 // There may be multiple threads trying to mark the same dep node green concurrently
788 let dep_node_index = {
789 // Copy the fingerprint from the previous graph,
790 // so we don't have to recompute it
791 let fingerprint = data.previous.fingerprint_by_index(prev_dep_node_index);
793 // We allocating an entry for the node in the current dependency graph and
794 // adding all the appropriate edges imported from the previous graph
795 data.current.intern_node(*dep_node, current_deps, fingerprint)
798 // ... emitting any stored diagnostic ...
800 // FIXME: Store the fact that a node has diagnostics in a bit in the dep graph somewhere
801 // Maybe store a list on disk and encode this fact in the DepNodeState
802 let diagnostics = tcx.queries.on_disk_cache.load_diagnostics(tcx, prev_dep_node_index);
804 #[cfg(not(parallel_compiler))]
806 data.colors.get(prev_dep_node_index).is_none(),
807 "DepGraph::try_mark_previous_green() - Duplicate DepNodeColor \
812 if unlikely!(!diagnostics.is_empty()) {
813 self.emit_diagnostics(tcx, data, dep_node_index, prev_dep_node_index, diagnostics);
816 // ... and finally storing a "Green" entry in the color map.
817 // Multiple threads can all write the same color here
818 data.colors.insert(prev_dep_node_index, DepNodeColor::Green(dep_node_index));
820 debug!("try_mark_previous_green({:?}) - END - successfully marked as green", dep_node);
824 /// Atomically emits some loaded diagnostics.
825 /// This may be called concurrently on multiple threads for the same dep node.
828 fn emit_diagnostics<'tcx>(
832 dep_node_index: DepNodeIndex,
833 prev_dep_node_index: SerializedDepNodeIndex,
834 diagnostics: Vec<Diagnostic>,
836 let mut emitting = data.emitting_diagnostics.lock();
838 if data.colors.get(prev_dep_node_index) == Some(DepNodeColor::Green(dep_node_index)) {
839 // The node is already green so diagnostics must have been emitted already
843 if emitting.insert(dep_node_index) {
844 // We were the first to insert the node in the set so this thread
845 // must emit the diagnostics and signal other potentially waiting
849 // Promote the previous diagnostics to the current session.
850 tcx.queries.on_disk_cache.store_diagnostics(dep_node_index, diagnostics.clone().into());
852 let handle = tcx.sess.diagnostic();
854 for diagnostic in diagnostics {
855 handle.emit_diagnostic(&diagnostic);
858 // Mark the node as green now that diagnostics are emitted
859 data.colors.insert(prev_dep_node_index, DepNodeColor::Green(dep_node_index));
861 // Remove the node from the set
862 data.emitting_diagnostics.lock().remove(&dep_node_index);
865 data.emitting_diagnostics_cond_var.notify_all();
867 // We must wait for the other thread to finish emitting the diagnostic
870 data.emitting_diagnostics_cond_var.wait(&mut emitting);
871 if data.colors.get(prev_dep_node_index) == Some(DepNodeColor::Green(dep_node_index))
879 // Returns true if the given node has been marked as green during the
880 // current compilation session. Used in various assertions
881 pub fn is_green(&self, dep_node: &DepNode) -> bool {
882 self.node_color(dep_node).map(|c| c.is_green()).unwrap_or(false)
885 // This method loads all on-disk cacheable query results into memory, so
886 // they can be written out to the new cache file again. Most query results
887 // will already be in memory but in the case where we marked something as
888 // green but then did not need the value, that value will never have been
891 // This method will only load queries that will end up in the disk cache.
892 // Other queries will not be executed.
893 pub fn exec_cache_promotions(&self, tcx: TyCtxt<'_>) {
894 let _prof_timer = tcx.prof.generic_activity("incr_comp_query_cache_promotion");
896 let data = self.data.as_ref().unwrap();
897 for prev_index in data.colors.values.indices() {
898 match data.colors.get(prev_index) {
899 Some(DepNodeColor::Green(_)) => {
900 let dep_node = data.previous.index_to_node(prev_index);
901 dep_node.try_load_from_on_disk_cache(tcx);
903 None | Some(DepNodeColor::Red) => {
904 // We can skip red nodes because a node can only be marked
905 // as red if the query result was recomputed and thus is
906 // already in memory.
912 fn next_virtual_depnode_index(&self) -> DepNodeIndex {
913 let index = self.virtual_dep_node_index.fetch_add(1, Relaxed);
914 DepNodeIndex::from_u32(index)
918 fn def_id_corresponds_to_hir_dep_node(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
919 let hir_id = tcx.hir().as_local_hir_id(def_id).unwrap();
920 def_id.index == hir_id.owner
923 /// A "work product" is an intermediate result that we save into the
924 /// incremental directory for later re-use. The primary example are
925 /// the object files that we save for each partition at code
928 /// Each work product is associated with a dep-node, representing the
929 /// process that produced the work-product. If that dep-node is found
930 /// to be dirty when we load up, then we will delete the work-product
931 /// at load time. If the work-product is found to be clean, then we
932 /// will keep a record in the `previous_work_products` list.
934 /// In addition, work products have an associated hash. This hash is
935 /// an extra hash that can be used to decide if the work-product from
936 /// a previous compilation can be re-used (in addition to the dirty
939 /// As the primary example, consider the object files we generate for
940 /// each partition. In the first run, we create partitions based on
941 /// the symbols that need to be compiled. For each partition P, we
942 /// hash the symbols in P and create a `WorkProduct` record associated
943 /// with `DepNode::CodegenUnit(P)`; the hash is the set of symbols
946 /// The next time we compile, if the `DepNode::CodegenUnit(P)` is
947 /// judged to be clean (which means none of the things we read to
948 /// generate the partition were found to be dirty), it will be loaded
949 /// into previous work products. We will then regenerate the set of
950 /// symbols in the partition P and hash them (note that new symbols
951 /// may be added -- for example, new monomorphizations -- even if
952 /// nothing in P changed!). We will compare that hash against the
953 /// previous hash. If it matches up, we can reuse the object file.
954 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
955 pub struct WorkProduct {
956 pub cgu_name: String,
957 /// Saved files associated with this CGU.
958 pub saved_files: Vec<(WorkProductFileKind, String)>,
961 #[derive(Clone, Copy, Debug, RustcEncodable, RustcDecodable, PartialEq)]
962 pub enum WorkProductFileKind {
971 edges: SmallVec<[DepNodeIndex; 8]>,
972 fingerprint: Fingerprint,
975 /// `CurrentDepGraph` stores the dependency graph for the current session.
976 /// It will be populated as we run queries or tasks.
978 /// The nodes in it are identified by an index (`DepNodeIndex`).
979 /// The data for each node is stored in its `DepNodeData`, found in the `data` field.
981 /// We never remove nodes from the graph: they are only added.
983 /// This struct uses two locks internally. The `data` and `node_to_node_index` fields are
984 /// locked separately. Operations that take a `DepNodeIndex` typically just access
987 /// The only operation that must manipulate both locks is adding new nodes, in which case
988 /// we first acquire the `node_to_node_index` lock and then, once a new node is to be inserted,
989 /// acquire the lock on `data.`
990 pub(super) struct CurrentDepGraph {
991 data: Lock<IndexVec<DepNodeIndex, DepNodeData>>,
992 node_to_node_index: Sharded<FxHashMap<DepNode, DepNodeIndex>>,
994 /// Used to trap when a specific edge is added to the graph.
995 /// This is used for debug purposes and is only active with `debug_assertions`.
997 forbidden_edge: Option<EdgeFilter>,
999 /// Anonymous `DepNode`s are nodes whose IDs we compute from the list of
1000 /// their edges. This has the beneficial side-effect that multiple anonymous
1001 /// nodes can be coalesced into one without changing the semantics of the
1002 /// dependency graph. However, the merging of nodes can lead to a subtle
1003 /// problem during red-green marking: The color of an anonymous node from
1004 /// the current session might "shadow" the color of the node with the same
1005 /// ID from the previous session. In order to side-step this problem, we make
1006 /// sure that anonymous `NodeId`s allocated in different sessions don't overlap.
1007 /// This is implemented by mixing a session-key into the ID fingerprint of
1008 /// each anon node. The session-key is just a random number generated when
1009 /// the `DepGraph` is created.
1010 anon_id_seed: Fingerprint,
1012 /// These are simple counters that are for profiling and
1013 /// debugging and only active with `debug_assertions`.
1014 total_read_count: AtomicU64,
1015 total_duplicate_read_count: AtomicU64,
1018 impl CurrentDepGraph {
1019 fn new(prev_graph_node_count: usize) -> CurrentDepGraph {
1020 use std::time::{SystemTime, UNIX_EPOCH};
1022 let duration = SystemTime::now().duration_since(UNIX_EPOCH).unwrap();
1023 let nanos = duration.as_secs() * 1_000_000_000 + duration.subsec_nanos() as u64;
1024 let mut stable_hasher = StableHasher::new();
1025 nanos.hash(&mut stable_hasher);
1027 let forbidden_edge = if cfg!(debug_assertions) {
1028 match env::var("RUST_FORBID_DEP_GRAPH_EDGE") {
1029 Ok(s) => match EdgeFilter::new(&s) {
1031 Err(err) => bug!("RUST_FORBID_DEP_GRAPH_EDGE invalid: {}", err),
1039 // Pre-allocate the dep node structures. We over-allocate a little so
1040 // that we hopefully don't have to re-allocate during this compilation
1041 // session. The over-allocation is 2% plus a small constant to account
1042 // for the fact that in very small crates 2% might not be enough.
1043 let new_node_count_estimate = (prev_graph_node_count * 102) / 100 + 200;
1046 data: Lock::new(IndexVec::with_capacity(new_node_count_estimate)),
1047 node_to_node_index: Sharded::new(|| {
1048 FxHashMap::with_capacity_and_hasher(
1049 new_node_count_estimate / sharded::SHARDS,
1053 anon_id_seed: stable_hasher.finish(),
1055 total_read_count: AtomicU64::new(0),
1056 total_duplicate_read_count: AtomicU64::new(0),
1063 task_deps: TaskDeps,
1064 fingerprint: Fingerprint,
1066 self.alloc_node(node, task_deps.reads, fingerprint)
1069 fn complete_anon_task(&self, kind: DepKind, task_deps: TaskDeps) -> DepNodeIndex {
1070 debug_assert!(!kind.is_eval_always());
1072 let mut hasher = StableHasher::new();
1074 // The dep node indices are hashed here instead of hashing the dep nodes of the
1075 // dependencies. These indices may refer to different nodes per session, but this isn't
1076 // a problem here because we that ensure the final dep node hash is per session only by
1077 // combining it with the per session random number `anon_id_seed`. This hash only need
1078 // to map the dependencies to a single value on a per session basis.
1079 task_deps.reads.hash(&mut hasher);
1081 let target_dep_node = DepNode {
1084 // Fingerprint::combine() is faster than sending Fingerprint
1085 // through the StableHasher (at least as long as StableHasher
1087 hash: self.anon_id_seed.combine(hasher.finish()),
1090 self.intern_node(target_dep_node, task_deps.reads, Fingerprint::ZERO)
1096 edges: SmallVec<[DepNodeIndex; 8]>,
1097 fingerprint: Fingerprint,
1100 !self.node_to_node_index.get_shard_by_value(&dep_node).lock().contains_key(&dep_node)
1102 self.intern_node(dep_node, edges, fingerprint)
1108 edges: SmallVec<[DepNodeIndex; 8]>,
1109 fingerprint: Fingerprint,
1111 match self.node_to_node_index.get_shard_by_value(&dep_node).lock().entry(dep_node) {
1112 Entry::Occupied(entry) => *entry.get(),
1113 Entry::Vacant(entry) => {
1114 let mut data = self.data.lock();
1115 let dep_node_index = DepNodeIndex::new(data.len());
1116 data.push(DepNodeData { node: dep_node, edges, fingerprint });
1117 entry.insert(dep_node_index);
1126 fn read_index(&self, source: DepNodeIndex) {
1127 ty::tls::with_context_opt(|icx| {
1128 let icx = if let Some(icx) = icx { icx } else { return };
1129 if let Some(task_deps) = icx.task_deps {
1130 let mut task_deps = task_deps.lock();
1131 if cfg!(debug_assertions) {
1132 self.current.total_read_count.fetch_add(1, Relaxed);
1134 if task_deps.read_set.insert(source) {
1135 task_deps.reads.push(source);
1137 #[cfg(debug_assertions)]
1139 if let Some(target) = task_deps.node {
1140 let data = self.current.data.lock();
1141 if let Some(ref forbidden_edge) = self.current.forbidden_edge {
1142 let source = data[source].node;
1143 if forbidden_edge.test(&source, &target) {
1144 bug!("forbidden edge {:?} -> {:?} created", source, target)
1149 } else if cfg!(debug_assertions) {
1150 self.current.total_duplicate_read_count.fetch_add(1, Relaxed);
1157 pub struct TaskDeps {
1158 #[cfg(debug_assertions)]
1159 node: Option<DepNode>,
1160 reads: SmallVec<[DepNodeIndex; 8]>,
1161 read_set: FxHashSet<DepNodeIndex>,
1164 // A data structure that stores Option<DepNodeColor> values as a contiguous
1165 // array, using one u32 per entry.
1166 struct DepNodeColorMap {
1167 values: IndexVec<SerializedDepNodeIndex, AtomicU32>,
1170 const COMPRESSED_NONE: u32 = 0;
1171 const COMPRESSED_RED: u32 = 1;
1172 const COMPRESSED_FIRST_GREEN: u32 = 2;
1174 impl DepNodeColorMap {
1175 fn new(size: usize) -> DepNodeColorMap {
1176 DepNodeColorMap { values: (0..size).map(|_| AtomicU32::new(COMPRESSED_NONE)).collect() }
1179 fn get(&self, index: SerializedDepNodeIndex) -> Option<DepNodeColor> {
1180 match self.values[index].load(Ordering::Acquire) {
1181 COMPRESSED_NONE => None,
1182 COMPRESSED_RED => Some(DepNodeColor::Red),
1184 Some(DepNodeColor::Green(DepNodeIndex::from_u32(value - COMPRESSED_FIRST_GREEN)))
1189 fn insert(&self, index: SerializedDepNodeIndex, color: DepNodeColor) {
1190 self.values[index].store(
1192 DepNodeColor::Red => COMPRESSED_RED,
1193 DepNodeColor::Green(index) => index.as_u32() + COMPRESSED_FIRST_GREEN,