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-rw-r--r--compiler/rustc_incremental/Cargo.toml22
-rw-r--r--compiler/rustc_incremental/src/assert_dep_graph.rs446
-rw-r--r--compiler/rustc_incremental/src/assert_module_sources.rs178
-rw-r--r--compiler/rustc_incremental/src/lib.rs30
-rw-r--r--compiler/rustc_incremental/src/persist/README.md3
-rw-r--r--compiler/rustc_incremental/src/persist/data.rs13
-rw-r--r--compiler/rustc_incremental/src/persist/dirty_clean.rs480
-rw-r--r--compiler/rustc_incremental/src/persist/file_format.rs195
-rw-r--r--compiler/rustc_incremental/src/persist/fs.rs984
-rw-r--r--compiler/rustc_incremental/src/persist/fs/tests.rs84
-rw-r--r--compiler/rustc_incremental/src/persist/load.rs235
-rw-r--r--compiler/rustc_incremental/src/persist/mod.rs25
-rw-r--r--compiler/rustc_incremental/src/persist/save.rs188
-rw-r--r--compiler/rustc_incremental/src/persist/work_product.rs59
14 files changed, 2942 insertions, 0 deletions
diff --git a/compiler/rustc_incremental/Cargo.toml b/compiler/rustc_incremental/Cargo.toml
new file mode 100644
index 000000000..d3c425a07
--- /dev/null
+++ b/compiler/rustc_incremental/Cargo.toml
@@ -0,0 +1,22 @@
+[package]
+name = "rustc_incremental"
+version = "0.0.0"
+edition = "2021"
+
+[lib]
+doctest = false
+
+[dependencies]
+rustc_graphviz = { path = "../rustc_graphviz" }
+tracing = "0.1"
+rand = "0.8.4"
+rustc_middle = { path = "../rustc_middle" }
+rustc_data_structures = { path = "../rustc_data_structures" }
+rustc_hir = { path = "../rustc_hir" }
+rustc_serialize = { path = "../rustc_serialize" }
+rustc_ast = { path = "../rustc_ast" }
+rustc_macros = { path = "../rustc_macros" }
+rustc_span = { path = "../rustc_span" }
+rustc_fs_util = { path = "../rustc_fs_util" }
+rustc_session = { path = "../rustc_session" }
+rustc_errors = { path = "../rustc_errors" }
diff --git a/compiler/rustc_incremental/src/assert_dep_graph.rs b/compiler/rustc_incremental/src/assert_dep_graph.rs
new file mode 100644
index 000000000..69e482ce8
--- /dev/null
+++ b/compiler/rustc_incremental/src/assert_dep_graph.rs
@@ -0,0 +1,446 @@
+//! This pass is only used for the UNIT TESTS and DEBUGGING NEEDS
+//! around dependency graph construction. It serves two purposes; it
+//! will dump graphs in graphviz form to disk, and it searches for
+//! `#[rustc_if_this_changed]` and `#[rustc_then_this_would_need]`
+//! annotations. These annotations can be used to test whether paths
+//! exist in the graph. These checks run after codegen, so they view the
+//! the final state of the dependency graph. Note that there are
+//! similar assertions found in `persist::dirty_clean` which check the
+//! **initial** state of the dependency graph, just after it has been
+//! loaded from disk.
+//!
+//! In this code, we report errors on each `rustc_if_this_changed`
+//! annotation. If a path exists in all cases, then we would report
+//! "all path(s) exist". Otherwise, we report: "no path to `foo`" for
+//! each case where no path exists. `ui` tests can then be
+//! used to check when paths exist or do not.
+//!
+//! The full form of the `rustc_if_this_changed` annotation is
+//! `#[rustc_if_this_changed("foo")]`, which will report a
+//! source node of `foo(def_id)`. The `"foo"` is optional and
+//! defaults to `"Hir"` if omitted.
+//!
+//! Example:
+//!
+//! ```ignore (needs flags)
+//! #[rustc_if_this_changed(Hir)]
+//! fn foo() { }
+//!
+//! #[rustc_then_this_would_need(codegen)] //~ ERROR no path from `foo`
+//! fn bar() { }
+//!
+//! #[rustc_then_this_would_need(codegen)] //~ ERROR OK
+//! fn baz() { foo(); }
+//! ```
+
+use rustc_ast as ast;
+use rustc_data_structures::fx::FxHashSet;
+use rustc_data_structures::graph::implementation::{Direction, NodeIndex, INCOMING, OUTGOING};
+use rustc_graphviz as dot;
+use rustc_hir as hir;
+use rustc_hir::def_id::DefId;
+use rustc_hir::intravisit::{self, Visitor};
+use rustc_middle::dep_graph::{
+ DepGraphQuery, DepKind, DepNode, DepNodeExt, DepNodeFilter, EdgeFilter,
+};
+use rustc_middle::hir::nested_filter;
+use rustc_middle::ty::TyCtxt;
+use rustc_span::symbol::{sym, Symbol};
+use rustc_span::Span;
+
+use std::env;
+use std::fs::{self, File};
+use std::io::{BufWriter, Write};
+
+#[allow(missing_docs)]
+pub fn assert_dep_graph(tcx: TyCtxt<'_>) {
+ tcx.dep_graph.with_ignore(|| {
+ if tcx.sess.opts.unstable_opts.dump_dep_graph {
+ tcx.dep_graph.with_query(dump_graph);
+ }
+
+ if !tcx.sess.opts.unstable_opts.query_dep_graph {
+ return;
+ }
+
+ // if the `rustc_attrs` feature is not enabled, then the
+ // attributes we are interested in cannot be present anyway, so
+ // skip the walk.
+ if !tcx.features().rustc_attrs {
+ return;
+ }
+
+ // Find annotations supplied by user (if any).
+ let (if_this_changed, then_this_would_need) = {
+ let mut visitor =
+ IfThisChanged { tcx, if_this_changed: vec![], then_this_would_need: vec![] };
+ visitor.process_attrs(hir::CRATE_HIR_ID);
+ tcx.hir().visit_all_item_likes_in_crate(&mut visitor);
+ (visitor.if_this_changed, visitor.then_this_would_need)
+ };
+
+ if !if_this_changed.is_empty() || !then_this_would_need.is_empty() {
+ assert!(
+ tcx.sess.opts.unstable_opts.query_dep_graph,
+ "cannot use the `#[{}]` or `#[{}]` annotations \
+ without supplying `-Z query-dep-graph`",
+ sym::rustc_if_this_changed,
+ sym::rustc_then_this_would_need
+ );
+ }
+
+ // Check paths.
+ check_paths(tcx, &if_this_changed, &then_this_would_need);
+ })
+}
+
+type Sources = Vec<(Span, DefId, DepNode)>;
+type Targets = Vec<(Span, Symbol, hir::HirId, DepNode)>;
+
+struct IfThisChanged<'tcx> {
+ tcx: TyCtxt<'tcx>,
+ if_this_changed: Sources,
+ then_this_would_need: Targets,
+}
+
+impl<'tcx> IfThisChanged<'tcx> {
+ fn argument(&self, attr: &ast::Attribute) -> Option<Symbol> {
+ let mut value = None;
+ for list_item in attr.meta_item_list().unwrap_or_default() {
+ match list_item.ident() {
+ Some(ident) if list_item.is_word() && value.is_none() => value = Some(ident.name),
+ _ =>
+ // FIXME better-encapsulate meta_item (don't directly access `node`)
+ {
+ span_bug!(list_item.span(), "unexpected meta-item {:?}", list_item)
+ }
+ }
+ }
+ value
+ }
+
+ fn process_attrs(&mut self, hir_id: hir::HirId) {
+ let def_id = self.tcx.hir().local_def_id(hir_id);
+ let def_path_hash = self.tcx.def_path_hash(def_id.to_def_id());
+ let attrs = self.tcx.hir().attrs(hir_id);
+ for attr in attrs {
+ if attr.has_name(sym::rustc_if_this_changed) {
+ let dep_node_interned = self.argument(attr);
+ let dep_node = match dep_node_interned {
+ None => {
+ DepNode::from_def_path_hash(self.tcx, def_path_hash, DepKind::hir_owner)
+ }
+ Some(n) => {
+ match DepNode::from_label_string(self.tcx, n.as_str(), def_path_hash) {
+ Ok(n) => n,
+ Err(()) => {
+ self.tcx.sess.span_fatal(
+ attr.span,
+ &format!("unrecognized DepNode variant {:?}", n),
+ );
+ }
+ }
+ }
+ };
+ self.if_this_changed.push((attr.span, def_id.to_def_id(), dep_node));
+ } else if attr.has_name(sym::rustc_then_this_would_need) {
+ let dep_node_interned = self.argument(attr);
+ let dep_node = match dep_node_interned {
+ Some(n) => {
+ match DepNode::from_label_string(self.tcx, n.as_str(), def_path_hash) {
+ Ok(n) => n,
+ Err(()) => {
+ self.tcx.sess.span_fatal(
+ attr.span,
+ &format!("unrecognized DepNode variant {:?}", n),
+ );
+ }
+ }
+ }
+ None => {
+ self.tcx.sess.span_fatal(attr.span, "missing DepNode variant");
+ }
+ };
+ self.then_this_would_need.push((
+ attr.span,
+ dep_node_interned.unwrap(),
+ hir_id,
+ dep_node,
+ ));
+ }
+ }
+ }
+}
+
+impl<'tcx> Visitor<'tcx> for IfThisChanged<'tcx> {
+ type NestedFilter = nested_filter::OnlyBodies;
+
+ fn nested_visit_map(&mut self) -> Self::Map {
+ self.tcx.hir()
+ }
+
+ fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
+ self.process_attrs(item.hir_id());
+ intravisit::walk_item(self, item);
+ }
+
+ fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem<'tcx>) {
+ self.process_attrs(trait_item.hir_id());
+ intravisit::walk_trait_item(self, trait_item);
+ }
+
+ fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem<'tcx>) {
+ self.process_attrs(impl_item.hir_id());
+ intravisit::walk_impl_item(self, impl_item);
+ }
+
+ fn visit_field_def(&mut self, s: &'tcx hir::FieldDef<'tcx>) {
+ self.process_attrs(s.hir_id);
+ intravisit::walk_field_def(self, s);
+ }
+}
+
+fn check_paths<'tcx>(tcx: TyCtxt<'tcx>, if_this_changed: &Sources, then_this_would_need: &Targets) {
+ // Return early here so as not to construct the query, which is not cheap.
+ if if_this_changed.is_empty() {
+ for &(target_span, _, _, _) in then_this_would_need {
+ tcx.sess.span_err(target_span, "no `#[rustc_if_this_changed]` annotation detected");
+ }
+ return;
+ }
+ tcx.dep_graph.with_query(|query| {
+ for &(_, source_def_id, ref source_dep_node) in if_this_changed {
+ let dependents = query.transitive_predecessors(source_dep_node);
+ for &(target_span, ref target_pass, _, ref target_dep_node) in then_this_would_need {
+ if !dependents.contains(&target_dep_node) {
+ tcx.sess.span_err(
+ target_span,
+ &format!(
+ "no path from `{}` to `{}`",
+ tcx.def_path_str(source_def_id),
+ target_pass
+ ),
+ );
+ } else {
+ tcx.sess.span_err(target_span, "OK");
+ }
+ }
+ }
+ });
+}
+
+fn dump_graph(query: &DepGraphQuery) {
+ let path: String = env::var("RUST_DEP_GRAPH").unwrap_or_else(|_| "dep_graph".to_string());
+
+ let nodes = match env::var("RUST_DEP_GRAPH_FILTER") {
+ Ok(string) => {
+ // Expect one of: "-> target", "source -> target", or "source ->".
+ let edge_filter =
+ EdgeFilter::new(&string).unwrap_or_else(|e| bug!("invalid filter: {}", e));
+ let sources = node_set(&query, &edge_filter.source);
+ let targets = node_set(&query, &edge_filter.target);
+ filter_nodes(&query, &sources, &targets)
+ }
+ Err(_) => query.nodes().into_iter().map(|n| n.kind).collect(),
+ };
+ let edges = filter_edges(&query, &nodes);
+
+ {
+ // dump a .txt file with just the edges:
+ let txt_path = format!("{}.txt", path);
+ let mut file = BufWriter::new(File::create(&txt_path).unwrap());
+ for &(ref source, ref target) in &edges {
+ write!(file, "{:?} -> {:?}\n", source, target).unwrap();
+ }
+ }
+
+ {
+ // dump a .dot file in graphviz format:
+ let dot_path = format!("{}.dot", path);
+ let mut v = Vec::new();
+ dot::render(&GraphvizDepGraph(nodes, edges), &mut v).unwrap();
+ fs::write(dot_path, v).unwrap();
+ }
+}
+
+#[allow(missing_docs)]
+pub struct GraphvizDepGraph(FxHashSet<DepKind>, Vec<(DepKind, DepKind)>);
+
+impl<'a> dot::GraphWalk<'a> for GraphvizDepGraph {
+ type Node = DepKind;
+ type Edge = (DepKind, DepKind);
+ fn nodes(&self) -> dot::Nodes<'_, DepKind> {
+ let nodes: Vec<_> = self.0.iter().cloned().collect();
+ nodes.into()
+ }
+ fn edges(&self) -> dot::Edges<'_, (DepKind, DepKind)> {
+ self.1[..].into()
+ }
+ fn source(&self, edge: &(DepKind, DepKind)) -> DepKind {
+ edge.0
+ }
+ fn target(&self, edge: &(DepKind, DepKind)) -> DepKind {
+ edge.1
+ }
+}
+
+impl<'a> dot::Labeller<'a> for GraphvizDepGraph {
+ type Node = DepKind;
+ type Edge = (DepKind, DepKind);
+ fn graph_id(&self) -> dot::Id<'_> {
+ dot::Id::new("DependencyGraph").unwrap()
+ }
+ fn node_id(&self, n: &DepKind) -> dot::Id<'_> {
+ let s: String = format!("{:?}", n)
+ .chars()
+ .map(|c| if c == '_' || c.is_alphanumeric() { c } else { '_' })
+ .collect();
+ debug!("n={:?} s={:?}", n, s);
+ dot::Id::new(s).unwrap()
+ }
+ fn node_label(&self, n: &DepKind) -> dot::LabelText<'_> {
+ dot::LabelText::label(format!("{:?}", n))
+ }
+}
+
+// Given an optional filter like `"x,y,z"`, returns either `None` (no
+// filter) or the set of nodes whose labels contain all of those
+// substrings.
+fn node_set<'q>(
+ query: &'q DepGraphQuery,
+ filter: &DepNodeFilter,
+) -> Option<FxHashSet<&'q DepNode>> {
+ debug!("node_set(filter={:?})", filter);
+
+ if filter.accepts_all() {
+ return None;
+ }
+
+ Some(query.nodes().into_iter().filter(|n| filter.test(n)).collect())
+}
+
+fn filter_nodes<'q>(
+ query: &'q DepGraphQuery,
+ sources: &Option<FxHashSet<&'q DepNode>>,
+ targets: &Option<FxHashSet<&'q DepNode>>,
+) -> FxHashSet<DepKind> {
+ if let Some(sources) = sources {
+ if let Some(targets) = targets {
+ walk_between(query, sources, targets)
+ } else {
+ walk_nodes(query, sources, OUTGOING)
+ }
+ } else if let Some(targets) = targets {
+ walk_nodes(query, targets, INCOMING)
+ } else {
+ query.nodes().into_iter().map(|n| n.kind).collect()
+ }
+}
+
+fn walk_nodes<'q>(
+ query: &'q DepGraphQuery,
+ starts: &FxHashSet<&'q DepNode>,
+ direction: Direction,
+) -> FxHashSet<DepKind> {
+ let mut set = FxHashSet::default();
+ for &start in starts {
+ debug!("walk_nodes: start={:?} outgoing?={:?}", start, direction == OUTGOING);
+ if set.insert(start.kind) {
+ let mut stack = vec![query.indices[start]];
+ while let Some(index) = stack.pop() {
+ for (_, edge) in query.graph.adjacent_edges(index, direction) {
+ let neighbor_index = edge.source_or_target(direction);
+ let neighbor = query.graph.node_data(neighbor_index);
+ if set.insert(neighbor.kind) {
+ stack.push(neighbor_index);
+ }
+ }
+ }
+ }
+ }
+ set
+}
+
+fn walk_between<'q>(
+ query: &'q DepGraphQuery,
+ sources: &FxHashSet<&'q DepNode>,
+ targets: &FxHashSet<&'q DepNode>,
+) -> FxHashSet<DepKind> {
+ // This is a bit tricky. We want to include a node only if it is:
+ // (a) reachable from a source and (b) will reach a target. And we
+ // have to be careful about cycles etc. Luckily efficiency is not
+ // a big concern!
+
+ #[derive(Copy, Clone, PartialEq)]
+ enum State {
+ Undecided,
+ Deciding,
+ Included,
+ Excluded,
+ }
+
+ let mut node_states = vec![State::Undecided; query.graph.len_nodes()];
+
+ for &target in targets {
+ node_states[query.indices[target].0] = State::Included;
+ }
+
+ for source in sources.iter().map(|&n| query.indices[n]) {
+ recurse(query, &mut node_states, source);
+ }
+
+ return query
+ .nodes()
+ .into_iter()
+ .filter(|&n| {
+ let index = query.indices[n];
+ node_states[index.0] == State::Included
+ })
+ .map(|n| n.kind)
+ .collect();
+
+ fn recurse(query: &DepGraphQuery, node_states: &mut [State], node: NodeIndex) -> bool {
+ match node_states[node.0] {
+ // known to reach a target
+ State::Included => return true,
+
+ // known not to reach a target
+ State::Excluded => return false,
+
+ // backedge, not yet known, say false
+ State::Deciding => return false,
+
+ State::Undecided => {}
+ }
+
+ node_states[node.0] = State::Deciding;
+
+ for neighbor_index in query.graph.successor_nodes(node) {
+ if recurse(query, node_states, neighbor_index) {
+ node_states[node.0] = State::Included;
+ }
+ }
+
+ // if we didn't find a path to target, then set to excluded
+ if node_states[node.0] == State::Deciding {
+ node_states[node.0] = State::Excluded;
+ false
+ } else {
+ assert!(node_states[node.0] == State::Included);
+ true
+ }
+ }
+}
+
+fn filter_edges<'q>(
+ query: &'q DepGraphQuery,
+ nodes: &FxHashSet<DepKind>,
+) -> Vec<(DepKind, DepKind)> {
+ let uniq: FxHashSet<_> = query
+ .edges()
+ .into_iter()
+ .map(|(s, t)| (s.kind, t.kind))
+ .filter(|(source, target)| nodes.contains(source) && nodes.contains(target))
+ .collect();
+ uniq.into_iter().collect()
+}
diff --git a/compiler/rustc_incremental/src/assert_module_sources.rs b/compiler/rustc_incremental/src/assert_module_sources.rs
new file mode 100644
index 000000000..89d419bc8
--- /dev/null
+++ b/compiler/rustc_incremental/src/assert_module_sources.rs
@@ -0,0 +1,178 @@
+//! This pass is only used for UNIT TESTS related to incremental
+//! compilation. It tests whether a particular `.o` file will be re-used
+//! from a previous compilation or whether it must be regenerated.
+//!
+//! The user adds annotations to the crate of the following form:
+//!
+//! ```
+//! # #![feature(rustc_attrs)]
+//! #![rustc_partition_reused(module="spike", cfg="rpass2")]
+//! #![rustc_partition_codegened(module="spike-x", cfg="rpass2")]
+//! ```
+//!
+//! The first indicates (in the cfg `rpass2`) that `spike.o` will be
+//! reused, the second that `spike-x.o` will be recreated. If these
+//! annotations are inaccurate, errors are reported.
+//!
+//! The reason that we use `cfg=...` and not `#[cfg_attr]` is so that
+//! the HIR doesn't change as a result of the annotations, which might
+//! perturb the reuse results.
+//!
+//! `#![rustc_expected_cgu_reuse(module="spike", cfg="rpass2", kind="post-lto")]
+//! allows for doing a more fine-grained check to see if pre- or post-lto data
+//! was re-used.
+
+use rustc_ast as ast;
+use rustc_data_structures::fx::FxHashSet;
+use rustc_hir::def_id::LOCAL_CRATE;
+use rustc_middle::mir::mono::CodegenUnitNameBuilder;
+use rustc_middle::ty::TyCtxt;
+use rustc_session::cgu_reuse_tracker::*;
+use rustc_span::symbol::{sym, Symbol};
+
+#[allow(missing_docs)]
+pub fn assert_module_sources(tcx: TyCtxt<'_>) {
+ tcx.dep_graph.with_ignore(|| {
+ if tcx.sess.opts.incremental.is_none() {
+ return;
+ }
+
+ let available_cgus =
+ tcx.collect_and_partition_mono_items(()).1.iter().map(|cgu| cgu.name()).collect();
+
+ let ams = AssertModuleSource { tcx, available_cgus };
+
+ for attr in tcx.hir().attrs(rustc_hir::CRATE_HIR_ID) {
+ ams.check_attr(attr);
+ }
+ })
+}
+
+struct AssertModuleSource<'tcx> {
+ tcx: TyCtxt<'tcx>,
+ available_cgus: FxHashSet<Symbol>,
+}
+
+impl<'tcx> AssertModuleSource<'tcx> {
+ fn check_attr(&self, attr: &ast::Attribute) {
+ let (expected_reuse, comp_kind) = if attr.has_name(sym::rustc_partition_reused) {
+ (CguReuse::PreLto, ComparisonKind::AtLeast)
+ } else if attr.has_name(sym::rustc_partition_codegened) {
+ (CguReuse::No, ComparisonKind::Exact)
+ } else if attr.has_name(sym::rustc_expected_cgu_reuse) {
+ match self.field(attr, sym::kind) {
+ sym::no => (CguReuse::No, ComparisonKind::Exact),
+ sym::pre_dash_lto => (CguReuse::PreLto, ComparisonKind::Exact),
+ sym::post_dash_lto => (CguReuse::PostLto, ComparisonKind::Exact),
+ sym::any => (CguReuse::PreLto, ComparisonKind::AtLeast),
+ other => {
+ self.tcx.sess.span_fatal(
+ attr.span,
+ &format!("unknown cgu-reuse-kind `{}` specified", other),
+ );
+ }
+ }
+ } else {
+ return;
+ };
+
+ if !self.tcx.sess.opts.unstable_opts.query_dep_graph {
+ self.tcx.sess.span_fatal(
+ attr.span,
+ "found CGU-reuse attribute but `-Zquery-dep-graph` was not specified",
+ );
+ }
+
+ if !self.check_config(attr) {
+ debug!("check_attr: config does not match, ignoring attr");
+ return;
+ }
+
+ let user_path = self.field(attr, sym::module).to_string();
+ let crate_name = self.tcx.crate_name(LOCAL_CRATE).to_string();
+
+ if !user_path.starts_with(&crate_name) {
+ let msg = format!(
+ "Found malformed codegen unit name `{}`. \
+ Codegen units names must always start with the name of the \
+ crate (`{}` in this case).",
+ user_path, crate_name
+ );
+ self.tcx.sess.span_fatal(attr.span, &msg);
+ }
+
+ // Split of the "special suffix" if there is one.
+ let (user_path, cgu_special_suffix) = if let Some(index) = user_path.rfind('.') {
+ (&user_path[..index], Some(&user_path[index + 1..]))
+ } else {
+ (&user_path[..], None)
+ };
+
+ let mut iter = user_path.split('-');
+
+ // Remove the crate name
+ assert_eq!(iter.next().unwrap(), crate_name);
+
+ let cgu_path_components = iter.collect::<Vec<_>>();
+
+ let cgu_name_builder = &mut CodegenUnitNameBuilder::new(self.tcx);
+ let cgu_name =
+ cgu_name_builder.build_cgu_name(LOCAL_CRATE, cgu_path_components, cgu_special_suffix);
+
+ debug!("mapping '{}' to cgu name '{}'", self.field(attr, sym::module), cgu_name);
+
+ if !self.available_cgus.contains(&cgu_name) {
+ let mut cgu_names: Vec<&str> =
+ self.available_cgus.iter().map(|cgu| cgu.as_str()).collect();
+ cgu_names.sort();
+ self.tcx.sess.span_err(
+ attr.span,
+ &format!(
+ "no module named `{}` (mangled: {}). Available modules: {}",
+ user_path,
+ cgu_name,
+ cgu_names.join(", ")
+ ),
+ );
+ }
+
+ self.tcx.sess.cgu_reuse_tracker.set_expectation(
+ cgu_name,
+ &user_path,
+ attr.span,
+ expected_reuse,
+ comp_kind,
+ );
+ }
+
+ fn field(&self, attr: &ast::Attribute, name: Symbol) -> Symbol {
+ for item in attr.meta_item_list().unwrap_or_else(Vec::new) {
+ if item.has_name(name) {
+ if let Some(value) = item.value_str() {
+ return value;
+ } else {
+ self.tcx.sess.span_fatal(
+ item.span(),
+ &format!("associated value expected for `{}`", name),
+ );
+ }
+ }
+ }
+
+ self.tcx.sess.span_fatal(attr.span, &format!("no field `{}`", name));
+ }
+
+ /// Scan for a `cfg="foo"` attribute and check whether we have a
+ /// cfg flag called `foo`.
+ fn check_config(&self, attr: &ast::Attribute) -> bool {
+ let config = &self.tcx.sess.parse_sess.config;
+ let value = self.field(attr, sym::cfg);
+ debug!("check_config(config={:?}, value={:?})", config, value);
+ if config.iter().any(|&(name, _)| name == value) {
+ debug!("check_config: matched");
+ return true;
+ }
+ debug!("check_config: no match found");
+ false
+ }
+}
diff --git a/compiler/rustc_incremental/src/lib.rs b/compiler/rustc_incremental/src/lib.rs
new file mode 100644
index 000000000..1e88e8091
--- /dev/null
+++ b/compiler/rustc_incremental/src/lib.rs
@@ -0,0 +1,30 @@
+//! Support for serializing the dep-graph and reloading it.
+
+#![deny(missing_docs)]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
+#![feature(let_else)]
+#![recursion_limit = "256"]
+#![allow(rustc::potential_query_instability)]
+
+#[macro_use]
+extern crate rustc_middle;
+#[macro_use]
+extern crate tracing;
+
+mod assert_dep_graph;
+pub mod assert_module_sources;
+mod persist;
+
+use assert_dep_graph::assert_dep_graph;
+pub use persist::copy_cgu_workproduct_to_incr_comp_cache_dir;
+pub use persist::delete_workproduct_files;
+pub use persist::finalize_session_directory;
+pub use persist::garbage_collect_session_directories;
+pub use persist::in_incr_comp_dir;
+pub use persist::in_incr_comp_dir_sess;
+pub use persist::load_query_result_cache;
+pub use persist::prepare_session_directory;
+pub use persist::save_dep_graph;
+pub use persist::save_work_product_index;
+pub use persist::LoadResult;
+pub use persist::{build_dep_graph, load_dep_graph, DepGraphFuture};
diff --git a/compiler/rustc_incremental/src/persist/README.md b/compiler/rustc_incremental/src/persist/README.md
new file mode 100644
index 000000000..b01fe219e
--- /dev/null
+++ b/compiler/rustc_incremental/src/persist/README.md
@@ -0,0 +1,3 @@
+For info on how the incremental compilation works, see the [rustc dev guide].
+
+[rustc dev guide]: https://rustc-dev-guide.rust-lang.org/query.html
diff --git a/compiler/rustc_incremental/src/persist/data.rs b/compiler/rustc_incremental/src/persist/data.rs
new file mode 100644
index 000000000..81e541097
--- /dev/null
+++ b/compiler/rustc_incremental/src/persist/data.rs
@@ -0,0 +1,13 @@
+//! The data that we will serialize and deserialize.
+
+use rustc_macros::{Decodable, Encodable};
+use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
+
+#[derive(Debug, Encodable, Decodable)]
+pub struct SerializedWorkProduct {
+ /// node that produced the work-product
+ pub id: WorkProductId,
+
+ /// work-product data itself
+ pub work_product: WorkProduct,
+}
diff --git a/compiler/rustc_incremental/src/persist/dirty_clean.rs b/compiler/rustc_incremental/src/persist/dirty_clean.rs
new file mode 100644
index 000000000..710c4a01b
--- /dev/null
+++ b/compiler/rustc_incremental/src/persist/dirty_clean.rs
@@ -0,0 +1,480 @@
+//! Debugging code to test fingerprints computed for query results. For each node marked with
+//! `#[rustc_clean]` we will compare the fingerprint from the current and from the previous
+//! compilation session as appropriate:
+//!
+//! - `#[rustc_clean(cfg="rev2", except="typeck")]` if we are
+//! in `#[cfg(rev2)]`, then the fingerprints associated with
+//! `DepNode::typeck(X)` must be DIFFERENT (`X` is the `DefId` of the
+//! current node).
+//! - `#[rustc_clean(cfg="rev2")]` same as above, except that the
+//! fingerprints must be the SAME (along with all other fingerprints).
+//!
+//! - `#[rustc_clean(cfg="rev2", loaded_from_disk='typeck")]` asserts that
+//! the query result for `DepNode::typeck(X)` was actually
+//! loaded from disk (not just marked green). This can be useful
+//! to ensure that a test is actually exercising the deserialization
+//! logic for a particular query result. This can be combined with
+//! `except`
+//!
+//! Errors are reported if we are in the suitable configuration but
+//! the required condition is not met.
+
+use rustc_ast::{self as ast, Attribute, NestedMetaItem};
+use rustc_data_structures::fx::FxHashSet;
+use rustc_hir::def_id::LocalDefId;
+use rustc_hir::intravisit;
+use rustc_hir::Node as HirNode;
+use rustc_hir::{ImplItemKind, ItemKind as HirItem, TraitItemKind};
+use rustc_middle::dep_graph::{label_strs, DepNode, DepNodeExt};
+use rustc_middle::hir::nested_filter;
+use rustc_middle::ty::TyCtxt;
+use rustc_span::symbol::{sym, Symbol};
+use rustc_span::Span;
+use std::iter::FromIterator;
+use std::vec::Vec;
+
+const LOADED_FROM_DISK: Symbol = sym::loaded_from_disk;
+const EXCEPT: Symbol = sym::except;
+const CFG: Symbol = sym::cfg;
+
+// Base and Extra labels to build up the labels
+
+/// For typedef, constants, and statics
+const BASE_CONST: &[&str] = &[label_strs::type_of];
+
+/// DepNodes for functions + methods
+const BASE_FN: &[&str] = &[
+ // Callers will depend on the signature of these items, so we better test
+ label_strs::fn_sig,
+ label_strs::generics_of,
+ label_strs::predicates_of,
+ label_strs::type_of,
+ // And a big part of compilation (that we eventually want to cache) is type inference
+ // information:
+ label_strs::typeck,
+];
+
+/// DepNodes for Hir, which is pretty much everything
+const BASE_HIR: &[&str] = &[
+ // hir_owner and hir_owner_nodes should be computed for all nodes
+ label_strs::hir_owner,
+ label_strs::hir_owner_nodes,
+];
+
+/// `impl` implementation of struct/trait
+const BASE_IMPL: &[&str] =
+ &[label_strs::associated_item_def_ids, label_strs::generics_of, label_strs::impl_trait_ref];
+
+/// DepNodes for mir_built/Optimized, which is relevant in "executable"
+/// code, i.e., functions+methods
+const BASE_MIR: &[&str] = &[label_strs::optimized_mir, label_strs::promoted_mir];
+
+/// Struct, Enum and Union DepNodes
+///
+/// Note that changing the type of a field does not change the type of the struct or enum, but
+/// adding/removing fields or changing a fields name or visibility does.
+const BASE_STRUCT: &[&str] =
+ &[label_strs::generics_of, label_strs::predicates_of, label_strs::type_of];
+
+/// Trait definition `DepNode`s.
+/// Extra `DepNode`s for functions and methods.
+const EXTRA_ASSOCIATED: &[&str] = &[label_strs::associated_item];
+
+const EXTRA_TRAIT: &[&str] = &[];
+
+// Fully Built Labels
+
+const LABELS_CONST: &[&[&str]] = &[BASE_HIR, BASE_CONST];
+
+/// Constant/Typedef in an impl
+const LABELS_CONST_IN_IMPL: &[&[&str]] = &[BASE_HIR, BASE_CONST, EXTRA_ASSOCIATED];
+
+/// Trait-Const/Typedef DepNodes
+const LABELS_CONST_IN_TRAIT: &[&[&str]] = &[BASE_HIR, BASE_CONST, EXTRA_ASSOCIATED, EXTRA_TRAIT];
+
+/// Function `DepNode`s.
+const LABELS_FN: &[&[&str]] = &[BASE_HIR, BASE_MIR, BASE_FN];
+
+/// Method `DepNode`s.
+const LABELS_FN_IN_IMPL: &[&[&str]] = &[BASE_HIR, BASE_MIR, BASE_FN, EXTRA_ASSOCIATED];
+
+/// Trait method `DepNode`s.
+const LABELS_FN_IN_TRAIT: &[&[&str]] =
+ &[BASE_HIR, BASE_MIR, BASE_FN, EXTRA_ASSOCIATED, EXTRA_TRAIT];
+
+/// For generic cases like inline-assembly, modules, etc.
+const LABELS_HIR_ONLY: &[&[&str]] = &[BASE_HIR];
+
+/// Impl `DepNode`s.
+const LABELS_TRAIT: &[&[&str]] = &[
+ BASE_HIR,
+ &[label_strs::associated_item_def_ids, label_strs::predicates_of, label_strs::generics_of],
+];
+
+/// Impl `DepNode`s.
+const LABELS_IMPL: &[&[&str]] = &[BASE_HIR, BASE_IMPL];
+
+/// Abstract data type (struct, enum, union) `DepNode`s.
+const LABELS_ADT: &[&[&str]] = &[BASE_HIR, BASE_STRUCT];
+
+// FIXME: Struct/Enum/Unions Fields (there is currently no way to attach these)
+//
+// Fields are kind of separate from their containers, as they can change independently from
+// them. We should at least check
+//
+// type_of for these.
+
+type Labels = FxHashSet<String>;
+
+/// Represents the requested configuration by rustc_clean/dirty
+struct Assertion {
+ clean: Labels,
+ dirty: Labels,
+ loaded_from_disk: Labels,
+}
+
+pub fn check_dirty_clean_annotations(tcx: TyCtxt<'_>) {
+ if !tcx.sess.opts.unstable_opts.query_dep_graph {
+ return;
+ }
+
+ // can't add `#[rustc_clean]` etc without opting in to this feature
+ if !tcx.features().rustc_attrs {
+ return;
+ }
+
+ tcx.dep_graph.with_ignore(|| {
+ let mut dirty_clean_visitor = DirtyCleanVisitor { tcx, checked_attrs: Default::default() };
+
+ let crate_items = tcx.hir_crate_items(());
+
+ for id in crate_items.items() {
+ dirty_clean_visitor.check_item(id.def_id);
+ }
+
+ for id in crate_items.trait_items() {
+ dirty_clean_visitor.check_item(id.def_id);
+ }
+
+ for id in crate_items.impl_items() {
+ dirty_clean_visitor.check_item(id.def_id);
+ }
+
+ for id in crate_items.foreign_items() {
+ dirty_clean_visitor.check_item(id.def_id);
+ }
+
+ let mut all_attrs = FindAllAttrs { tcx, found_attrs: vec![] };
+ tcx.hir().walk_attributes(&mut all_attrs);
+
+ // Note that we cannot use the existing "unused attribute"-infrastructure
+ // here, since that is running before codegen. This is also the reason why
+ // all codegen-specific attributes are `AssumedUsed` in rustc_ast::feature_gate.
+ all_attrs.report_unchecked_attrs(dirty_clean_visitor.checked_attrs);
+ })
+}
+
+pub struct DirtyCleanVisitor<'tcx> {
+ tcx: TyCtxt<'tcx>,
+ checked_attrs: FxHashSet<ast::AttrId>,
+}
+
+impl<'tcx> DirtyCleanVisitor<'tcx> {
+ /// Possibly "deserialize" the attribute into a clean/dirty assertion
+ fn assertion_maybe(&mut self, item_id: LocalDefId, attr: &Attribute) -> Option<Assertion> {
+ assert!(attr.has_name(sym::rustc_clean));
+ if !check_config(self.tcx, attr) {
+ // skip: not the correct `cfg=`
+ return None;
+ }
+ let assertion = self.assertion_auto(item_id, attr);
+ Some(assertion)
+ }
+
+ /// Gets the "auto" assertion on pre-validated attr, along with the `except` labels.
+ fn assertion_auto(&mut self, item_id: LocalDefId, attr: &Attribute) -> Assertion {
+ let (name, mut auto) = self.auto_labels(item_id, attr);
+ let except = self.except(attr);
+ let loaded_from_disk = self.loaded_from_disk(attr);
+ for e in except.iter() {
+ if !auto.remove(e) {
+ let msg = format!(
+ "`except` specified DepNodes that can not be affected for \"{}\": \"{}\"",
+ name, e
+ );
+ self.tcx.sess.span_fatal(attr.span, &msg);
+ }
+ }
+ Assertion { clean: auto, dirty: except, loaded_from_disk }
+ }
+
+ /// `loaded_from_disk=` attribute value
+ fn loaded_from_disk(&self, attr: &Attribute) -> Labels {
+ for item in attr.meta_item_list().unwrap_or_else(Vec::new) {
+ if item.has_name(LOADED_FROM_DISK) {
+ let value = expect_associated_value(self.tcx, &item);
+ return self.resolve_labels(&item, value);
+ }
+ }
+ // If `loaded_from_disk=` is not specified, don't assert anything
+ Labels::default()
+ }
+
+ /// `except=` attribute value
+ fn except(&self, attr: &Attribute) -> Labels {
+ for item in attr.meta_item_list().unwrap_or_else(Vec::new) {
+ if item.has_name(EXCEPT) {
+ let value = expect_associated_value(self.tcx, &item);
+ return self.resolve_labels(&item, value);
+ }
+ }
+ // if no `label` or `except` is given, only the node's group are asserted
+ Labels::default()
+ }
+
+ /// Return all DepNode labels that should be asserted for this item.
+ /// index=0 is the "name" used for error messages
+ fn auto_labels(&mut self, item_id: LocalDefId, attr: &Attribute) -> (&'static str, Labels) {
+ let node = self.tcx.hir().get_by_def_id(item_id);
+ let (name, labels) = match node {
+ HirNode::Item(item) => {
+ match item.kind {
+ // note: these are in the same order as hir::Item_;
+ // FIXME(michaelwoerister): do commented out ones
+
+ // // An `extern crate` item, with optional original crate name,
+ // HirItem::ExternCrate(..), // intentionally no assertions
+
+ // // `use foo::bar::*;` or `use foo::bar::baz as quux;`
+ // HirItem::Use(..), // intentionally no assertions
+
+ // A `static` item
+ HirItem::Static(..) => ("ItemStatic", LABELS_CONST),
+
+ // A `const` item
+ HirItem::Const(..) => ("ItemConst", LABELS_CONST),
+
+ // A function declaration
+ HirItem::Fn(..) => ("ItemFn", LABELS_FN),
+
+ // // A module
+ HirItem::Mod(..) => ("ItemMod", LABELS_HIR_ONLY),
+
+ // // An external module
+ HirItem::ForeignMod { .. } => ("ItemForeignMod", LABELS_HIR_ONLY),
+
+ // Module-level inline assembly (from global_asm!)
+ HirItem::GlobalAsm(..) => ("ItemGlobalAsm", LABELS_HIR_ONLY),
+
+ // A type alias, e.g., `type Foo = Bar<u8>`
+ HirItem::TyAlias(..) => ("ItemTy", LABELS_HIR_ONLY),
+
+ // An enum definition, e.g., `enum Foo<A, B> {C<A>, D<B>}`
+ HirItem::Enum(..) => ("ItemEnum", LABELS_ADT),
+
+ // A struct definition, e.g., `struct Foo<A> {x: A}`
+ HirItem::Struct(..) => ("ItemStruct", LABELS_ADT),
+
+ // A union definition, e.g., `union Foo<A, B> {x: A, y: B}`
+ HirItem::Union(..) => ("ItemUnion", LABELS_ADT),
+
+ // Represents a Trait Declaration
+ HirItem::Trait(..) => ("ItemTrait", LABELS_TRAIT),
+
+ // An implementation, eg `impl<A> Trait for Foo { .. }`
+ HirItem::Impl { .. } => ("ItemKind::Impl", LABELS_IMPL),
+
+ _ => self.tcx.sess.span_fatal(
+ attr.span,
+ &format!(
+ "clean/dirty auto-assertions not yet defined \
+ for Node::Item.node={:?}",
+ item.kind
+ ),
+ ),
+ }
+ }
+ HirNode::TraitItem(item) => match item.kind {
+ TraitItemKind::Fn(..) => ("Node::TraitItem", LABELS_FN_IN_TRAIT),
+ TraitItemKind::Const(..) => ("NodeTraitConst", LABELS_CONST_IN_TRAIT),
+ TraitItemKind::Type(..) => ("NodeTraitType", LABELS_CONST_IN_TRAIT),
+ },
+ HirNode::ImplItem(item) => match item.kind {
+ ImplItemKind::Fn(..) => ("Node::ImplItem", LABELS_FN_IN_IMPL),
+ ImplItemKind::Const(..) => ("NodeImplConst", LABELS_CONST_IN_IMPL),
+ ImplItemKind::TyAlias(..) => ("NodeImplType", LABELS_CONST_IN_IMPL),
+ },
+ _ => self.tcx.sess.span_fatal(
+ attr.span,
+ &format!("clean/dirty auto-assertions not yet defined for {:?}", node),
+ ),
+ };
+ let labels =
+ Labels::from_iter(labels.iter().flat_map(|s| s.iter().map(|l| (*l).to_string())));
+ (name, labels)
+ }
+
+ fn resolve_labels(&self, item: &NestedMetaItem, value: Symbol) -> Labels {
+ let mut out = Labels::default();
+ for label in value.as_str().split(',') {
+ let label = label.trim();
+ if DepNode::has_label_string(label) {
+ if out.contains(label) {
+ self.tcx.sess.span_fatal(
+ item.span(),
+ &format!("dep-node label `{}` is repeated", label),
+ );
+ }
+ out.insert(label.to_string());
+ } else {
+ self.tcx
+ .sess
+ .span_fatal(item.span(), &format!("dep-node label `{}` not recognized", label));
+ }
+ }
+ out
+ }
+
+ fn dep_node_str(&self, dep_node: &DepNode) -> String {
+ if let Some(def_id) = dep_node.extract_def_id(self.tcx) {
+ format!("{:?}({})", dep_node.kind, self.tcx.def_path_str(def_id))
+ } else {
+ format!("{:?}({:?})", dep_node.kind, dep_node.hash)
+ }
+ }
+
+ fn assert_dirty(&self, item_span: Span, dep_node: DepNode) {
+ debug!("assert_dirty({:?})", dep_node);
+
+ if self.tcx.dep_graph.is_green(&dep_node) {
+ let dep_node_str = self.dep_node_str(&dep_node);
+ self.tcx
+ .sess
+ .span_err(item_span, &format!("`{}` should be dirty but is not", dep_node_str));
+ }
+ }
+
+ fn assert_clean(&self, item_span: Span, dep_node: DepNode) {
+ debug!("assert_clean({:?})", dep_node);
+
+ if self.tcx.dep_graph.is_red(&dep_node) {
+ let dep_node_str = self.dep_node_str(&dep_node);
+ self.tcx
+ .sess
+ .span_err(item_span, &format!("`{}` should be clean but is not", dep_node_str));
+ }
+ }
+
+ fn assert_loaded_from_disk(&self, item_span: Span, dep_node: DepNode) {
+ debug!("assert_loaded_from_disk({:?})", dep_node);
+
+ if !self.tcx.dep_graph.debug_was_loaded_from_disk(dep_node) {
+ let dep_node_str = self.dep_node_str(&dep_node);
+ self.tcx.sess.span_err(
+ item_span,
+ &format!("`{}` should have been loaded from disk but it was not", dep_node_str),
+ );
+ }
+ }
+
+ fn check_item(&mut self, item_id: LocalDefId) {
+ let item_span = self.tcx.def_span(item_id.to_def_id());
+ let def_path_hash = self.tcx.def_path_hash(item_id.to_def_id());
+ for attr in self.tcx.get_attrs(item_id.to_def_id(), sym::rustc_clean) {
+ let Some(assertion) = self.assertion_maybe(item_id, attr) else {
+ continue;
+ };
+ self.checked_attrs.insert(attr.id);
+ for label in assertion.clean {
+ let dep_node = DepNode::from_label_string(self.tcx, &label, def_path_hash).unwrap();
+ self.assert_clean(item_span, dep_node);
+ }
+ for label in assertion.dirty {
+ let dep_node = DepNode::from_label_string(self.tcx, &label, def_path_hash).unwrap();
+ self.assert_dirty(item_span, dep_node);
+ }
+ for label in assertion.loaded_from_disk {
+ let dep_node = DepNode::from_label_string(self.tcx, &label, def_path_hash).unwrap();
+ self.assert_loaded_from_disk(item_span, dep_node);
+ }
+ }
+ }
+}
+
+/// Given a `#[rustc_clean]` attribute, scan for a `cfg="foo"` attribute and check whether we have
+/// a cfg flag called `foo`.
+fn check_config(tcx: TyCtxt<'_>, attr: &Attribute) -> bool {
+ debug!("check_config(attr={:?})", attr);
+ let config = &tcx.sess.parse_sess.config;
+ debug!("check_config: config={:?}", config);
+ let mut cfg = None;
+ for item in attr.meta_item_list().unwrap_or_else(Vec::new) {
+ if item.has_name(CFG) {
+ let value = expect_associated_value(tcx, &item);
+ debug!("check_config: searching for cfg {:?}", value);
+ cfg = Some(config.contains(&(value, None)));
+ } else if !(item.has_name(EXCEPT) || item.has_name(LOADED_FROM_DISK)) {
+ tcx.sess.span_err(attr.span, &format!("unknown item `{}`", item.name_or_empty()));
+ }
+ }
+
+ match cfg {
+ None => tcx.sess.span_fatal(attr.span, "no cfg attribute"),
+ Some(c) => c,
+ }
+}
+
+fn expect_associated_value(tcx: TyCtxt<'_>, item: &NestedMetaItem) -> Symbol {
+ if let Some(value) = item.value_str() {
+ value
+ } else {
+ let msg = if let Some(ident) = item.ident() {
+ format!("associated value expected for `{}`", ident)
+ } else {
+ "expected an associated value".to_string()
+ };
+
+ tcx.sess.span_fatal(item.span(), &msg);
+ }
+}
+
+// A visitor that collects all #[rustc_clean] attributes from
+// the HIR. It is used to verify that we really ran checks for all annotated
+// nodes.
+pub struct FindAllAttrs<'tcx> {
+ tcx: TyCtxt<'tcx>,
+ found_attrs: Vec<&'tcx Attribute>,
+}
+
+impl<'tcx> FindAllAttrs<'tcx> {
+ fn is_active_attr(&mut self, attr: &Attribute) -> bool {
+ if attr.has_name(sym::rustc_clean) && check_config(self.tcx, attr) {
+ return true;
+ }
+
+ false
+ }
+
+ fn report_unchecked_attrs(&self, mut checked_attrs: FxHashSet<ast::AttrId>) {
+ for attr in &self.found_attrs {
+ if !checked_attrs.contains(&attr.id) {
+ self.tcx.sess.span_err(attr.span, "found unchecked `#[rustc_clean]` attribute");
+ checked_attrs.insert(attr.id);
+ }
+ }
+ }
+}
+
+impl<'tcx> intravisit::Visitor<'tcx> for FindAllAttrs<'tcx> {
+ type NestedFilter = nested_filter::All;
+
+ fn nested_visit_map(&mut self) -> Self::Map {
+ self.tcx.hir()
+ }
+
+ fn visit_attribute(&mut self, attr: &'tcx Attribute) {
+ if self.is_active_attr(attr) {
+ self.found_attrs.push(attr);
+ }
+ }
+}
diff --git a/compiler/rustc_incremental/src/persist/file_format.rs b/compiler/rustc_incremental/src/persist/file_format.rs
new file mode 100644
index 000000000..2dbd4b6bc
--- /dev/null
+++ b/compiler/rustc_incremental/src/persist/file_format.rs
@@ -0,0 +1,195 @@
+//! This module defines a generic file format that allows to check if a given
+//! file generated by incremental compilation was generated by a compatible
+//! compiler version. This file format is used for the on-disk version of the
+//! dependency graph and the exported metadata hashes.
+//!
+//! In practice "compatible compiler version" means "exactly the same compiler
+//! version", since the header encodes the git commit hash of the compiler.
+//! Since we can always just ignore the incremental compilation cache and
+//! compiler versions don't change frequently for the typical user, being
+//! conservative here practically has no downside.
+
+use std::env;
+use std::fs;
+use std::io::{self, Read};
+use std::path::{Path, PathBuf};
+
+use rustc_data_structures::memmap::Mmap;
+use rustc_serialize::opaque::{FileEncodeResult, FileEncoder};
+use rustc_serialize::Encoder;
+use rustc_session::Session;
+
+/// The first few bytes of files generated by incremental compilation.
+const FILE_MAGIC: &[u8] = b"RSIC";
+
+/// Change this if the header format changes.
+const HEADER_FORMAT_VERSION: u16 = 0;
+
+/// A version string that hopefully is always different for compiler versions
+/// with different encodings of incremental compilation artifacts. Contains
+/// the Git commit hash.
+const RUSTC_VERSION: Option<&str> = option_env!("CFG_VERSION");
+
+pub(crate) fn write_file_header(stream: &mut FileEncoder, nightly_build: bool) {
+ stream.emit_raw_bytes(FILE_MAGIC);
+ stream
+ .emit_raw_bytes(&[(HEADER_FORMAT_VERSION >> 0) as u8, (HEADER_FORMAT_VERSION >> 8) as u8]);
+
+ let rustc_version = rustc_version(nightly_build);
+ assert_eq!(rustc_version.len(), (rustc_version.len() as u8) as usize);
+ stream.emit_raw_bytes(&[rustc_version.len() as u8]);
+ stream.emit_raw_bytes(rustc_version.as_bytes());
+}
+
+pub(crate) fn save_in<F>(sess: &Session, path_buf: PathBuf, name: &str, encode: F)
+where
+ F: FnOnce(FileEncoder) -> FileEncodeResult,
+{
+ debug!("save: storing data in {}", path_buf.display());
+
+ // Delete the old file, if any.
+ // Note: It's important that we actually delete the old file and not just
+ // truncate and overwrite it, since it might be a shared hard-link, the
+ // underlying data of which we don't want to modify.
+ //
+ // We have to ensure we have dropped the memory maps to this file
+ // before performing this removal.
+ match fs::remove_file(&path_buf) {
+ Ok(()) => {
+ debug!("save: remove old file");
+ }
+ Err(err) if err.kind() == io::ErrorKind::NotFound => (),
+ Err(err) => {
+ sess.err(&format!(
+ "unable to delete old {} at `{}`: {}",
+ name,
+ path_buf.display(),
+ err
+ ));
+ return;
+ }
+ }
+
+ let mut encoder = match FileEncoder::new(&path_buf) {
+ Ok(encoder) => encoder,
+ Err(err) => {
+ sess.err(&format!("failed to create {} at `{}`: {}", name, path_buf.display(), err));
+ return;
+ }
+ };
+
+ write_file_header(&mut encoder, sess.is_nightly_build());
+
+ match encode(encoder) {
+ Ok(position) => {
+ sess.prof.artifact_size(
+ &name.replace(' ', "_"),
+ path_buf.file_name().unwrap().to_string_lossy(),
+ position as u64,
+ );
+ debug!("save: data written to disk successfully");
+ }
+ Err(err) => {
+ sess.err(&format!("failed to write {} to `{}`: {}", name, path_buf.display(), err));
+ }
+ }
+}
+
+/// Reads the contents of a file with a file header as defined in this module.
+///
+/// - Returns `Ok(Some(data, pos))` if the file existed and was generated by a
+/// compatible compiler version. `data` is the entire contents of the file
+/// and `pos` points to the first byte after the header.
+/// - Returns `Ok(None)` if the file did not exist or was generated by an
+/// incompatible version of the compiler.
+/// - Returns `Err(..)` if some kind of IO error occurred while reading the
+/// file.
+pub fn read_file(
+ report_incremental_info: bool,
+ path: &Path,
+ nightly_build: bool,
+) -> io::Result<Option<(Mmap, usize)>> {
+ let file = match fs::File::open(path) {
+ Ok(file) => file,
+ Err(err) if err.kind() == io::ErrorKind::NotFound => return Ok(None),
+ Err(err) => return Err(err),
+ };
+ // SAFETY: This process must not modify nor remove the backing file while the memory map lives.
+ // For the dep-graph and the work product index, it is as soon as the decoding is done.
+ // For the query result cache, the memory map is dropped in save_dep_graph before calling
+ // save_in and trying to remove the backing file.
+ //
+ // There is no way to prevent another process from modifying this file.
+ let mmap = unsafe { Mmap::map(file) }?;
+
+ let mut file = io::Cursor::new(&*mmap);
+
+ // Check FILE_MAGIC
+ {
+ debug_assert!(FILE_MAGIC.len() == 4);
+ let mut file_magic = [0u8; 4];
+ file.read_exact(&mut file_magic)?;
+ if file_magic != FILE_MAGIC {
+ report_format_mismatch(report_incremental_info, path, "Wrong FILE_MAGIC");
+ return Ok(None);
+ }
+ }
+
+ // Check HEADER_FORMAT_VERSION
+ {
+ debug_assert!(::std::mem::size_of_val(&HEADER_FORMAT_VERSION) == 2);
+ let mut header_format_version = [0u8; 2];
+ file.read_exact(&mut header_format_version)?;
+ let header_format_version =
+ (header_format_version[0] as u16) | ((header_format_version[1] as u16) << 8);
+
+ if header_format_version != HEADER_FORMAT_VERSION {
+ report_format_mismatch(report_incremental_info, path, "Wrong HEADER_FORMAT_VERSION");
+ return Ok(None);
+ }
+ }
+
+ // Check RUSTC_VERSION
+ {
+ let mut rustc_version_str_len = [0u8; 1];
+ file.read_exact(&mut rustc_version_str_len)?;
+ let rustc_version_str_len = rustc_version_str_len[0] as usize;
+ let mut buffer = vec![0; rustc_version_str_len];
+ file.read_exact(&mut buffer)?;
+
+ if buffer != rustc_version(nightly_build).as_bytes() {
+ report_format_mismatch(report_incremental_info, path, "Different compiler version");
+ return Ok(None);
+ }
+ }
+
+ let post_header_start_pos = file.position() as usize;
+ Ok(Some((mmap, post_header_start_pos)))
+}
+
+fn report_format_mismatch(report_incremental_info: bool, file: &Path, message: &str) {
+ debug!("read_file: {}", message);
+
+ if report_incremental_info {
+ eprintln!(
+ "[incremental] ignoring cache artifact `{}`: {}",
+ file.file_name().unwrap().to_string_lossy(),
+ message
+ );
+ }
+}
+
+fn rustc_version(nightly_build: bool) -> String {
+ if nightly_build {
+ if let Some(val) = env::var_os("RUSTC_FORCE_RUSTC_VERSION") {
+ return val.to_string_lossy().into_owned();
+ }
+ }
+
+ RUSTC_VERSION
+ .expect(
+ "Cannot use rustc without explicit version for \
+ incremental compilation",
+ )
+ .to_string()
+}
diff --git a/compiler/rustc_incremental/src/persist/fs.rs b/compiler/rustc_incremental/src/persist/fs.rs
new file mode 100644
index 000000000..25c1b2e1c
--- /dev/null
+++ b/compiler/rustc_incremental/src/persist/fs.rs
@@ -0,0 +1,984 @@
+//! This module manages how the incremental compilation cache is represented in
+//! the file system.
+//!
+//! Incremental compilation caches are managed according to a copy-on-write
+//! strategy: Once a complete, consistent cache version is finalized, it is
+//! never modified. Instead, when a subsequent compilation session is started,
+//! the compiler will allocate a new version of the cache that starts out as
+//! a copy of the previous version. Then only this new copy is modified and it
+//! will not be visible to other processes until it is finalized. This ensures
+//! that multiple compiler processes can be executed concurrently for the same
+//! crate without interfering with each other or blocking each other.
+//!
+//! More concretely this is implemented via the following protocol:
+//!
+//! 1. For a newly started compilation session, the compiler allocates a
+//! new `session` directory within the incremental compilation directory.
+//! This session directory will have a unique name that ends with the suffix
+//! "-working" and that contains a creation timestamp.
+//! 2. Next, the compiler looks for the newest finalized session directory,
+//! that is, a session directory from a previous compilation session that
+//! has been marked as valid and consistent. A session directory is
+//! considered finalized if the "-working" suffix in the directory name has
+//! been replaced by the SVH of the crate.
+//! 3. Once the compiler has found a valid, finalized session directory, it will
+//! hard-link/copy its contents into the new "-working" directory. If all
+//! goes well, it will have its own, private copy of the source directory and
+//! subsequently not have to worry about synchronizing with other compiler
+//! processes.
+//! 4. Now the compiler can do its normal compilation process, which involves
+//! reading and updating its private session directory.
+//! 5. When compilation finishes without errors, the private session directory
+//! will be in a state where it can be used as input for other compilation
+//! sessions. That is, it will contain a dependency graph and cache artifacts
+//! that are consistent with the state of the source code it was compiled
+//! from, with no need to change them ever again. At this point, the compiler
+//! finalizes and "publishes" its private session directory by renaming it
+//! from "s-{timestamp}-{random}-working" to "s-{timestamp}-{SVH}".
+//! 6. At this point the "old" session directory that we copied our data from
+//! at the beginning of the session has become obsolete because we have just
+//! published a more current version. Thus the compiler will delete it.
+//!
+//! ## Garbage Collection
+//!
+//! Naively following the above protocol might lead to old session directories
+//! piling up if a compiler instance crashes for some reason before its able to
+//! remove its private session directory. In order to avoid wasting disk space,
+//! the compiler also does some garbage collection each time it is started in
+//! incremental compilation mode. Specifically, it will scan the incremental
+//! compilation directory for private session directories that are not in use
+//! any more and will delete those. It will also delete any finalized session
+//! directories for a given crate except for the most recent one.
+//!
+//! ## Synchronization
+//!
+//! There is some synchronization needed in order for the compiler to be able to
+//! determine whether a given private session directory is not in used any more.
+//! This is done by creating a lock file for each session directory and
+//! locking it while the directory is still being used. Since file locks have
+//! operating system support, we can rely on the lock being released if the
+//! compiler process dies for some unexpected reason. Thus, when garbage
+//! collecting private session directories, the collecting process can determine
+//! whether the directory is still in use by trying to acquire a lock on the
+//! file. If locking the file fails, the original process must still be alive.
+//! If locking the file succeeds, we know that the owning process is not alive
+//! any more and we can safely delete the directory.
+//! There is still a small time window between the original process creating the
+//! lock file and actually locking it. In order to minimize the chance that
+//! another process tries to acquire the lock in just that instance, only
+//! session directories that are older than a few seconds are considered for
+//! garbage collection.
+//!
+//! Another case that has to be considered is what happens if one process
+//! deletes a finalized session directory that another process is currently
+//! trying to copy from. This case is also handled via the lock file. Before
+//! a process starts copying a finalized session directory, it will acquire a
+//! shared lock on the directory's lock file. Any garbage collecting process,
+//! on the other hand, will acquire an exclusive lock on the lock file.
+//! Thus, if a directory is being collected, any reader process will fail
+//! acquiring the shared lock and will leave the directory alone. Conversely,
+//! if a collecting process can't acquire the exclusive lock because the
+//! directory is currently being read from, it will leave collecting that
+//! directory to another process at a later point in time.
+//! The exact same scheme is also used when reading the metadata hashes file
+//! from an extern crate. When a crate is compiled, the hash values of its
+//! metadata are stored in a file in its session directory. When the
+//! compilation session of another crate imports the first crate's metadata,
+//! it also has to read in the accompanying metadata hashes. It thus will access
+//! the finalized session directory of all crates it links to and while doing
+//! so, it will also place a read lock on that the respective session directory
+//! so that it won't be deleted while the metadata hashes are loaded.
+//!
+//! ## Preconditions
+//!
+//! This system relies on two features being available in the file system in
+//! order to work really well: file locking and hard linking.
+//! If hard linking is not available (like on FAT) the data in the cache
+//! actually has to be copied at the beginning of each session.
+//! If file locking does not work reliably (like on NFS), some of the
+//! synchronization will go haywire.
+//! In both cases we recommend to locate the incremental compilation directory
+//! on a file system that supports these things.
+//! It might be a good idea though to try and detect whether we are on an
+//! unsupported file system and emit a warning in that case. This is not yet
+//! implemented.
+
+use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_data_structures::svh::Svh;
+use rustc_data_structures::{base_n, flock};
+use rustc_errors::ErrorGuaranteed;
+use rustc_fs_util::{link_or_copy, LinkOrCopy};
+use rustc_session::{Session, StableCrateId};
+
+use std::fs as std_fs;
+use std::io::{self, ErrorKind};
+use std::mem;
+use std::path::{Path, PathBuf};
+use std::time::{Duration, SystemTime, UNIX_EPOCH};
+
+use rand::{thread_rng, RngCore};
+
+#[cfg(test)]
+mod tests;
+
+const LOCK_FILE_EXT: &str = ".lock";
+const DEP_GRAPH_FILENAME: &str = "dep-graph.bin";
+const STAGING_DEP_GRAPH_FILENAME: &str = "dep-graph.part.bin";
+const WORK_PRODUCTS_FILENAME: &str = "work-products.bin";
+const QUERY_CACHE_FILENAME: &str = "query-cache.bin";
+
+// We encode integers using the following base, so they are shorter than decimal
+// or hexadecimal numbers (we want short file and directory names). Since these
+// numbers will be used in file names, we choose an encoding that is not
+// case-sensitive (as opposed to base64, for example).
+const INT_ENCODE_BASE: usize = base_n::CASE_INSENSITIVE;
+
+/// Returns the path to a session's dependency graph.
+pub fn dep_graph_path(sess: &Session) -> PathBuf {
+ in_incr_comp_dir_sess(sess, DEP_GRAPH_FILENAME)
+}
+/// Returns the path to a session's staging dependency graph.
+///
+/// On the difference between dep-graph and staging dep-graph,
+/// see `build_dep_graph`.
+pub fn staging_dep_graph_path(sess: &Session) -> PathBuf {
+ in_incr_comp_dir_sess(sess, STAGING_DEP_GRAPH_FILENAME)
+}
+pub fn work_products_path(sess: &Session) -> PathBuf {
+ in_incr_comp_dir_sess(sess, WORK_PRODUCTS_FILENAME)
+}
+/// Returns the path to a session's query cache.
+pub fn query_cache_path(sess: &Session) -> PathBuf {
+ in_incr_comp_dir_sess(sess, QUERY_CACHE_FILENAME)
+}
+
+/// Locks a given session directory.
+pub fn lock_file_path(session_dir: &Path) -> PathBuf {
+ let crate_dir = session_dir.parent().unwrap();
+
+ let directory_name = session_dir.file_name().unwrap().to_string_lossy();
+ assert_no_characters_lost(&directory_name);
+
+ let dash_indices: Vec<_> = directory_name.match_indices('-').map(|(idx, _)| idx).collect();
+ if dash_indices.len() != 3 {
+ bug!(
+ "Encountered incremental compilation session directory with \
+ malformed name: {}",
+ session_dir.display()
+ )
+ }
+
+ crate_dir.join(&directory_name[0..dash_indices[2]]).with_extension(&LOCK_FILE_EXT[1..])
+}
+
+/// Returns the path for a given filename within the incremental compilation directory
+/// in the current session.
+pub fn in_incr_comp_dir_sess(sess: &Session, file_name: &str) -> PathBuf {
+ in_incr_comp_dir(&sess.incr_comp_session_dir(), file_name)
+}
+
+/// Returns the path for a given filename within the incremental compilation directory,
+/// not necessarily from the current session.
+///
+/// To ensure the file is part of the current session, use [`in_incr_comp_dir_sess`].
+pub fn in_incr_comp_dir(incr_comp_session_dir: &Path, file_name: &str) -> PathBuf {
+ incr_comp_session_dir.join(file_name)
+}
+
+/// Allocates the private session directory.
+///
+/// If the result of this function is `Ok`, we have a valid incremental
+/// compilation session directory. A valid session
+/// directory is one that contains a locked lock file. It may or may not contain
+/// a dep-graph and work products from a previous session.
+///
+/// This always attempts to load a dep-graph from the directory.
+/// If loading fails for some reason, we fallback to a disabled `DepGraph`.
+/// See [`rustc_interface::queries::dep_graph`].
+///
+/// If this function returns an error, it may leave behind an invalid session directory.
+/// The garbage collection will take care of it.
+///
+/// [`rustc_interface::queries::dep_graph`]: ../../rustc_interface/struct.Queries.html#structfield.dep_graph
+pub fn prepare_session_directory(
+ sess: &Session,
+ crate_name: &str,
+ stable_crate_id: StableCrateId,
+) -> Result<(), ErrorGuaranteed> {
+ if sess.opts.incremental.is_none() {
+ return Ok(());
+ }
+
+ let _timer = sess.timer("incr_comp_prepare_session_directory");
+
+ debug!("prepare_session_directory");
+
+ // {incr-comp-dir}/{crate-name-and-disambiguator}
+ let crate_dir = crate_path(sess, crate_name, stable_crate_id);
+ debug!("crate-dir: {}", crate_dir.display());
+ create_dir(sess, &crate_dir, "crate")?;
+
+ // Hack: canonicalize the path *after creating the directory*
+ // because, on windows, long paths can cause problems;
+ // canonicalization inserts this weird prefix that makes windows
+ // tolerate long paths.
+ let crate_dir = match crate_dir.canonicalize() {
+ Ok(v) => v,
+ Err(err) => {
+ let reported = sess.err(&format!(
+ "incremental compilation: error canonicalizing path `{}`: {}",
+ crate_dir.display(),
+ err
+ ));
+ return Err(reported);
+ }
+ };
+
+ let mut source_directories_already_tried = FxHashSet::default();
+
+ loop {
+ // Generate a session directory of the form:
+ //
+ // {incr-comp-dir}/{crate-name-and-disambiguator}/s-{timestamp}-{random}-working
+ let session_dir = generate_session_dir_path(&crate_dir);
+ debug!("session-dir: {}", session_dir.display());
+
+ // Lock the new session directory. If this fails, return an
+ // error without retrying
+ let (directory_lock, lock_file_path) = lock_directory(sess, &session_dir)?;
+
+ // Now that we have the lock, we can actually create the session
+ // directory
+ create_dir(sess, &session_dir, "session")?;
+
+ // Find a suitable source directory to copy from. Ignore those that we
+ // have already tried before.
+ let source_directory = find_source_directory(&crate_dir, &source_directories_already_tried);
+
+ let Some(source_directory) = source_directory else {
+ // There's nowhere to copy from, we're done
+ debug!(
+ "no source directory found. Continuing with empty session \
+ directory."
+ );
+
+ sess.init_incr_comp_session(session_dir, directory_lock, false);
+ return Ok(());
+ };
+
+ debug!("attempting to copy data from source: {}", source_directory.display());
+
+ // Try copying over all files from the source directory
+ if let Ok(allows_links) = copy_files(sess, &session_dir, &source_directory) {
+ debug!("successfully copied data from: {}", source_directory.display());
+
+ if !allows_links {
+ sess.warn(&format!(
+ "Hard linking files in the incremental \
+ compilation cache failed. Copying files \
+ instead. Consider moving the cache \
+ directory to a file system which supports \
+ hard linking in session dir `{}`",
+ session_dir.display()
+ ));
+ }
+
+ sess.init_incr_comp_session(session_dir, directory_lock, true);
+ return Ok(());
+ } else {
+ debug!("copying failed - trying next directory");
+
+ // Something went wrong while trying to copy/link files from the
+ // source directory. Try again with a different one.
+ source_directories_already_tried.insert(source_directory);
+
+ // Try to remove the session directory we just allocated. We don't
+ // know if there's any garbage in it from the failed copy action.
+ if let Err(err) = safe_remove_dir_all(&session_dir) {
+ sess.warn(&format!(
+ "Failed to delete partly initialized \
+ session dir `{}`: {}",
+ session_dir.display(),
+ err
+ ));
+ }
+
+ delete_session_dir_lock_file(sess, &lock_file_path);
+ mem::drop(directory_lock);
+ }
+ }
+}
+
+/// This function finalizes and thus 'publishes' the session directory by
+/// renaming it to `s-{timestamp}-{svh}` and releasing the file lock.
+/// If there have been compilation errors, however, this function will just
+/// delete the presumably invalid session directory.
+pub fn finalize_session_directory(sess: &Session, svh: Svh) {
+ if sess.opts.incremental.is_none() {
+ return;
+ }
+
+ let _timer = sess.timer("incr_comp_finalize_session_directory");
+
+ let incr_comp_session_dir: PathBuf = sess.incr_comp_session_dir().clone();
+
+ if sess.has_errors_or_delayed_span_bugs() {
+ // If there have been any errors during compilation, we don't want to
+ // publish this session directory. Rather, we'll just delete it.
+
+ debug!(
+ "finalize_session_directory() - invalidating session directory: {}",
+ incr_comp_session_dir.display()
+ );
+
+ if let Err(err) = safe_remove_dir_all(&*incr_comp_session_dir) {
+ sess.warn(&format!(
+ "Error deleting incremental compilation \
+ session directory `{}`: {}",
+ incr_comp_session_dir.display(),
+ err
+ ));
+ }
+
+ let lock_file_path = lock_file_path(&*incr_comp_session_dir);
+ delete_session_dir_lock_file(sess, &lock_file_path);
+ sess.mark_incr_comp_session_as_invalid();
+ }
+
+ debug!("finalize_session_directory() - session directory: {}", incr_comp_session_dir.display());
+
+ let old_sub_dir_name = incr_comp_session_dir.file_name().unwrap().to_string_lossy();
+ assert_no_characters_lost(&old_sub_dir_name);
+
+ // Keep the 's-{timestamp}-{random-number}' prefix, but replace the
+ // '-working' part with the SVH of the crate
+ let dash_indices: Vec<_> = old_sub_dir_name.match_indices('-').map(|(idx, _)| idx).collect();
+ if dash_indices.len() != 3 {
+ bug!(
+ "Encountered incremental compilation session directory with \
+ malformed name: {}",
+ incr_comp_session_dir.display()
+ )
+ }
+
+ // State: "s-{timestamp}-{random-number}-"
+ let mut new_sub_dir_name = String::from(&old_sub_dir_name[..=dash_indices[2]]);
+
+ // Append the svh
+ base_n::push_str(svh.as_u64() as u128, INT_ENCODE_BASE, &mut new_sub_dir_name);
+
+ // Create the full path
+ let new_path = incr_comp_session_dir.parent().unwrap().join(new_sub_dir_name);
+ debug!("finalize_session_directory() - new path: {}", new_path.display());
+
+ match rename_path_with_retry(&*incr_comp_session_dir, &new_path, 3) {
+ Ok(_) => {
+ debug!("finalize_session_directory() - directory renamed successfully");
+
+ // This unlocks the directory
+ sess.finalize_incr_comp_session(new_path);
+ }
+ Err(e) => {
+ // Warn about the error. However, no need to abort compilation now.
+ sess.warn(&format!(
+ "Error finalizing incremental compilation \
+ session directory `{}`: {}",
+ incr_comp_session_dir.display(),
+ e
+ ));
+
+ debug!("finalize_session_directory() - error, marking as invalid");
+ // Drop the file lock, so we can garage collect
+ sess.mark_incr_comp_session_as_invalid();
+ }
+ }
+
+ let _ = garbage_collect_session_directories(sess);
+}
+
+pub fn delete_all_session_dir_contents(sess: &Session) -> io::Result<()> {
+ let sess_dir_iterator = sess.incr_comp_session_dir().read_dir()?;
+ for entry in sess_dir_iterator {
+ let entry = entry?;
+ safe_remove_file(&entry.path())?
+ }
+ Ok(())
+}
+
+fn copy_files(sess: &Session, target_dir: &Path, source_dir: &Path) -> Result<bool, ()> {
+ // We acquire a shared lock on the lock file of the directory, so that
+ // nobody deletes it out from under us while we are reading from it.
+ let lock_file_path = lock_file_path(source_dir);
+
+ // not exclusive
+ let Ok(_lock) = flock::Lock::new(
+ &lock_file_path,
+ false, // don't wait,
+ false, // don't create
+ false,
+ ) else {
+ // Could not acquire the lock, don't try to copy from here
+ return Err(());
+ };
+
+ let Ok(source_dir_iterator) = source_dir.read_dir() else {
+ return Err(());
+ };
+
+ let mut files_linked = 0;
+ let mut files_copied = 0;
+
+ for entry in source_dir_iterator {
+ match entry {
+ Ok(entry) => {
+ let file_name = entry.file_name();
+
+ let target_file_path = target_dir.join(file_name);
+ let source_path = entry.path();
+
+ debug!("copying into session dir: {}", source_path.display());
+ match link_or_copy(source_path, target_file_path) {
+ Ok(LinkOrCopy::Link) => files_linked += 1,
+ Ok(LinkOrCopy::Copy) => files_copied += 1,
+ Err(_) => return Err(()),
+ }
+ }
+ Err(_) => return Err(()),
+ }
+ }
+
+ if sess.opts.unstable_opts.incremental_info {
+ eprintln!(
+ "[incremental] session directory: \
+ {} files hard-linked",
+ files_linked
+ );
+ eprintln!(
+ "[incremental] session directory: \
+ {} files copied",
+ files_copied
+ );
+ }
+
+ Ok(files_linked > 0 || files_copied == 0)
+}
+
+/// Generates unique directory path of the form:
+/// {crate_dir}/s-{timestamp}-{random-number}-working
+fn generate_session_dir_path(crate_dir: &Path) -> PathBuf {
+ let timestamp = timestamp_to_string(SystemTime::now());
+ debug!("generate_session_dir_path: timestamp = {}", timestamp);
+ let random_number = thread_rng().next_u32();
+ debug!("generate_session_dir_path: random_number = {}", random_number);
+
+ let directory_name = format!(
+ "s-{}-{}-working",
+ timestamp,
+ base_n::encode(random_number as u128, INT_ENCODE_BASE)
+ );
+ debug!("generate_session_dir_path: directory_name = {}", directory_name);
+ let directory_path = crate_dir.join(directory_name);
+ debug!("generate_session_dir_path: directory_path = {}", directory_path.display());
+ directory_path
+}
+
+fn create_dir(sess: &Session, path: &Path, dir_tag: &str) -> Result<(), ErrorGuaranteed> {
+ match std_fs::create_dir_all(path) {
+ Ok(()) => {
+ debug!("{} directory created successfully", dir_tag);
+ Ok(())
+ }
+ Err(err) => {
+ let reported = sess.err(&format!(
+ "Could not create incremental compilation {} \
+ directory `{}`: {}",
+ dir_tag,
+ path.display(),
+ err
+ ));
+ Err(reported)
+ }
+ }
+}
+
+/// Allocate the lock-file and lock it.
+fn lock_directory(
+ sess: &Session,
+ session_dir: &Path,
+) -> Result<(flock::Lock, PathBuf), ErrorGuaranteed> {
+ let lock_file_path = lock_file_path(session_dir);
+ debug!("lock_directory() - lock_file: {}", lock_file_path.display());
+
+ match flock::Lock::new(
+ &lock_file_path,
+ false, // don't wait
+ true, // create the lock file
+ true,
+ ) {
+ // the lock should be exclusive
+ Ok(lock) => Ok((lock, lock_file_path)),
+ Err(lock_err) => {
+ let mut err = sess.struct_err(&format!(
+ "incremental compilation: could not create \
+ session directory lock file: {}",
+ lock_err
+ ));
+ if flock::Lock::error_unsupported(&lock_err) {
+ err.note(&format!(
+ "the filesystem for the incremental path at {} \
+ does not appear to support locking, consider changing the \
+ incremental path to a filesystem that supports locking \
+ or disable incremental compilation",
+ session_dir.display()
+ ));
+ if std::env::var_os("CARGO").is_some() {
+ err.help(
+ "incremental compilation can be disabled by setting the \
+ environment variable CARGO_INCREMENTAL=0 (see \
+ https://doc.rust-lang.org/cargo/reference/profiles.html#incremental)",
+ );
+ err.help(
+ "the entire build directory can be changed to a different \
+ filesystem by setting the environment variable CARGO_TARGET_DIR \
+ to a different path (see \
+ https://doc.rust-lang.org/cargo/reference/config.html#buildtarget-dir)",
+ );
+ }
+ }
+ Err(err.emit())
+ }
+ }
+}
+
+fn delete_session_dir_lock_file(sess: &Session, lock_file_path: &Path) {
+ if let Err(err) = safe_remove_file(&lock_file_path) {
+ sess.warn(&format!(
+ "Error deleting lock file for incremental \
+ compilation session directory `{}`: {}",
+ lock_file_path.display(),
+ err
+ ));
+ }
+}
+
+/// Finds the most recent published session directory that is not in the
+/// ignore-list.
+fn find_source_directory(
+ crate_dir: &Path,
+ source_directories_already_tried: &FxHashSet<PathBuf>,
+) -> Option<PathBuf> {
+ let iter = crate_dir
+ .read_dir()
+ .unwrap() // FIXME
+ .filter_map(|e| e.ok().map(|e| e.path()));
+
+ find_source_directory_in_iter(iter, source_directories_already_tried)
+}
+
+fn find_source_directory_in_iter<I>(
+ iter: I,
+ source_directories_already_tried: &FxHashSet<PathBuf>,
+) -> Option<PathBuf>
+where
+ I: Iterator<Item = PathBuf>,
+{
+ let mut best_candidate = (UNIX_EPOCH, None);
+
+ for session_dir in iter {
+ debug!("find_source_directory_in_iter - inspecting `{}`", session_dir.display());
+
+ let directory_name = session_dir.file_name().unwrap().to_string_lossy();
+ assert_no_characters_lost(&directory_name);
+
+ if source_directories_already_tried.contains(&session_dir)
+ || !is_session_directory(&directory_name)
+ || !is_finalized(&directory_name)
+ {
+ debug!("find_source_directory_in_iter - ignoring");
+ continue;
+ }
+
+ let timestamp = extract_timestamp_from_session_dir(&directory_name).unwrap_or_else(|_| {
+ bug!("unexpected incr-comp session dir: {}", session_dir.display())
+ });
+
+ if timestamp > best_candidate.0 {
+ best_candidate = (timestamp, Some(session_dir.clone()));
+ }
+ }
+
+ best_candidate.1
+}
+
+fn is_finalized(directory_name: &str) -> bool {
+ !directory_name.ends_with("-working")
+}
+
+fn is_session_directory(directory_name: &str) -> bool {
+ directory_name.starts_with("s-") && !directory_name.ends_with(LOCK_FILE_EXT)
+}
+
+fn is_session_directory_lock_file(file_name: &str) -> bool {
+ file_name.starts_with("s-") && file_name.ends_with(LOCK_FILE_EXT)
+}
+
+fn extract_timestamp_from_session_dir(directory_name: &str) -> Result<SystemTime, ()> {
+ if !is_session_directory(directory_name) {
+ return Err(());
+ }
+
+ let dash_indices: Vec<_> = directory_name.match_indices('-').map(|(idx, _)| idx).collect();
+ if dash_indices.len() != 3 {
+ return Err(());
+ }
+
+ string_to_timestamp(&directory_name[dash_indices[0] + 1..dash_indices[1]])
+}
+
+fn timestamp_to_string(timestamp: SystemTime) -> String {
+ let duration = timestamp.duration_since(UNIX_EPOCH).unwrap();
+ let micros = duration.as_secs() * 1_000_000 + (duration.subsec_nanos() as u64) / 1000;
+ base_n::encode(micros as u128, INT_ENCODE_BASE)
+}
+
+fn string_to_timestamp(s: &str) -> Result<SystemTime, ()> {
+ let micros_since_unix_epoch = u64::from_str_radix(s, INT_ENCODE_BASE as u32);
+
+ if micros_since_unix_epoch.is_err() {
+ return Err(());
+ }
+
+ let micros_since_unix_epoch = micros_since_unix_epoch.unwrap();
+
+ let duration = Duration::new(
+ micros_since_unix_epoch / 1_000_000,
+ 1000 * (micros_since_unix_epoch % 1_000_000) as u32,
+ );
+ Ok(UNIX_EPOCH + duration)
+}
+
+fn crate_path(sess: &Session, crate_name: &str, stable_crate_id: StableCrateId) -> PathBuf {
+ let incr_dir = sess.opts.incremental.as_ref().unwrap().clone();
+
+ let stable_crate_id = base_n::encode(stable_crate_id.to_u64() as u128, INT_ENCODE_BASE);
+
+ let crate_name = format!("{}-{}", crate_name, stable_crate_id);
+ incr_dir.join(crate_name)
+}
+
+fn assert_no_characters_lost(s: &str) {
+ if s.contains('\u{FFFD}') {
+ bug!("Could not losslessly convert '{}'.", s)
+ }
+}
+
+fn is_old_enough_to_be_collected(timestamp: SystemTime) -> bool {
+ timestamp < SystemTime::now() - Duration::from_secs(10)
+}
+
+/// Runs garbage collection for the current session.
+pub fn garbage_collect_session_directories(sess: &Session) -> io::Result<()> {
+ debug!("garbage_collect_session_directories() - begin");
+
+ let session_directory = sess.incr_comp_session_dir();
+ debug!(
+ "garbage_collect_session_directories() - session directory: {}",
+ session_directory.display()
+ );
+
+ let crate_directory = session_directory.parent().unwrap();
+ debug!(
+ "garbage_collect_session_directories() - crate directory: {}",
+ crate_directory.display()
+ );
+
+ // First do a pass over the crate directory, collecting lock files and
+ // session directories
+ let mut session_directories = FxHashSet::default();
+ let mut lock_files = FxHashSet::default();
+
+ for dir_entry in crate_directory.read_dir()? {
+ let Ok(dir_entry) = dir_entry else {
+ // Ignore any errors
+ continue;
+ };
+
+ let entry_name = dir_entry.file_name();
+ let entry_name = entry_name.to_string_lossy();
+
+ if is_session_directory_lock_file(&entry_name) {
+ assert_no_characters_lost(&entry_name);
+ lock_files.insert(entry_name.into_owned());
+ } else if is_session_directory(&entry_name) {
+ assert_no_characters_lost(&entry_name);
+ session_directories.insert(entry_name.into_owned());
+ } else {
+ // This is something we don't know, leave it alone
+ }
+ }
+
+ // Now map from lock files to session directories
+ let lock_file_to_session_dir: FxHashMap<String, Option<String>> = lock_files
+ .into_iter()
+ .map(|lock_file_name| {
+ assert!(lock_file_name.ends_with(LOCK_FILE_EXT));
+ let dir_prefix_end = lock_file_name.len() - LOCK_FILE_EXT.len();
+ let session_dir = {
+ let dir_prefix = &lock_file_name[0..dir_prefix_end];
+ session_directories.iter().find(|dir_name| dir_name.starts_with(dir_prefix))
+ };
+ (lock_file_name, session_dir.map(String::clone))
+ })
+ .collect();
+
+ // Delete all lock files, that don't have an associated directory. They must
+ // be some kind of leftover
+ for (lock_file_name, directory_name) in &lock_file_to_session_dir {
+ if directory_name.is_none() {
+ let Ok(timestamp) = extract_timestamp_from_session_dir(lock_file_name) else {
+ debug!(
+ "found lock-file with malformed timestamp: {}",
+ crate_directory.join(&lock_file_name).display()
+ );
+ // Ignore it
+ continue;
+ };
+
+ let lock_file_path = crate_directory.join(&**lock_file_name);
+
+ if is_old_enough_to_be_collected(timestamp) {
+ debug!(
+ "garbage_collect_session_directories() - deleting \
+ garbage lock file: {}",
+ lock_file_path.display()
+ );
+ delete_session_dir_lock_file(sess, &lock_file_path);
+ } else {
+ debug!(
+ "garbage_collect_session_directories() - lock file with \
+ no session dir not old enough to be collected: {}",
+ lock_file_path.display()
+ );
+ }
+ }
+ }
+
+ // Filter out `None` directories
+ let lock_file_to_session_dir: FxHashMap<String, String> = lock_file_to_session_dir
+ .into_iter()
+ .filter_map(|(lock_file_name, directory_name)| directory_name.map(|n| (lock_file_name, n)))
+ .collect();
+
+ // Delete all session directories that don't have a lock file.
+ for directory_name in session_directories {
+ if !lock_file_to_session_dir.values().any(|dir| *dir == directory_name) {
+ let path = crate_directory.join(directory_name);
+ if let Err(err) = safe_remove_dir_all(&path) {
+ sess.warn(&format!(
+ "Failed to garbage collect invalid incremental \
+ compilation session directory `{}`: {}",
+ path.display(),
+ err
+ ));
+ }
+ }
+ }
+
+ // Now garbage collect the valid session directories.
+ let mut deletion_candidates = vec![];
+
+ for (lock_file_name, directory_name) in &lock_file_to_session_dir {
+ debug!("garbage_collect_session_directories() - inspecting: {}", directory_name);
+
+ let Ok(timestamp) = extract_timestamp_from_session_dir(directory_name) else {
+ debug!(
+ "found session-dir with malformed timestamp: {}",
+ crate_directory.join(directory_name).display()
+ );
+ // Ignore it
+ continue;
+ };
+
+ if is_finalized(directory_name) {
+ let lock_file_path = crate_directory.join(lock_file_name);
+ match flock::Lock::new(
+ &lock_file_path,
+ false, // don't wait
+ false, // don't create the lock-file
+ true,
+ ) {
+ // get an exclusive lock
+ Ok(lock) => {
+ debug!(
+ "garbage_collect_session_directories() - \
+ successfully acquired lock"
+ );
+ debug!(
+ "garbage_collect_session_directories() - adding \
+ deletion candidate: {}",
+ directory_name
+ );
+
+ // Note that we are holding on to the lock
+ deletion_candidates.push((
+ timestamp,
+ crate_directory.join(directory_name),
+ Some(lock),
+ ));
+ }
+ Err(_) => {
+ debug!(
+ "garbage_collect_session_directories() - \
+ not collecting, still in use"
+ );
+ }
+ }
+ } else if is_old_enough_to_be_collected(timestamp) {
+ // When cleaning out "-working" session directories, i.e.
+ // session directories that might still be in use by another
+ // compiler instance, we only look a directories that are
+ // at least ten seconds old. This is supposed to reduce the
+ // chance of deleting a directory in the time window where
+ // the process has allocated the directory but has not yet
+ // acquired the file-lock on it.
+
+ // Try to acquire the directory lock. If we can't, it
+ // means that the owning process is still alive and we
+ // leave this directory alone.
+ let lock_file_path = crate_directory.join(lock_file_name);
+ match flock::Lock::new(
+ &lock_file_path,
+ false, // don't wait
+ false, // don't create the lock-file
+ true,
+ ) {
+ // get an exclusive lock
+ Ok(lock) => {
+ debug!(
+ "garbage_collect_session_directories() - \
+ successfully acquired lock"
+ );
+
+ delete_old(sess, &crate_directory.join(directory_name));
+
+ // Let's make it explicit that the file lock is released at this point,
+ // or rather, that we held on to it until here
+ mem::drop(lock);
+ }
+ Err(_) => {
+ debug!(
+ "garbage_collect_session_directories() - \
+ not collecting, still in use"
+ );
+ }
+ }
+ } else {
+ debug!(
+ "garbage_collect_session_directories() - not finalized, not \
+ old enough"
+ );
+ }
+ }
+
+ // Delete all but the most recent of the candidates
+ for (path, lock) in all_except_most_recent(deletion_candidates) {
+ debug!("garbage_collect_session_directories() - deleting `{}`", path.display());
+
+ if let Err(err) = safe_remove_dir_all(&path) {
+ sess.warn(&format!(
+ "Failed to garbage collect finalized incremental \
+ compilation session directory `{}`: {}",
+ path.display(),
+ err
+ ));
+ } else {
+ delete_session_dir_lock_file(sess, &lock_file_path(&path));
+ }
+
+ // Let's make it explicit that the file lock is released at this point,
+ // or rather, that we held on to it until here
+ mem::drop(lock);
+ }
+
+ Ok(())
+}
+
+fn delete_old(sess: &Session, path: &Path) {
+ debug!("garbage_collect_session_directories() - deleting `{}`", path.display());
+
+ if let Err(err) = safe_remove_dir_all(&path) {
+ sess.warn(&format!(
+ "Failed to garbage collect incremental compilation session directory `{}`: {}",
+ path.display(),
+ err
+ ));
+ } else {
+ delete_session_dir_lock_file(sess, &lock_file_path(&path));
+ }
+}
+
+fn all_except_most_recent(
+ deletion_candidates: Vec<(SystemTime, PathBuf, Option<flock::Lock>)>,
+) -> FxHashMap<PathBuf, Option<flock::Lock>> {
+ let most_recent = deletion_candidates.iter().map(|&(timestamp, ..)| timestamp).max();
+
+ if let Some(most_recent) = most_recent {
+ deletion_candidates
+ .into_iter()
+ .filter(|&(timestamp, ..)| timestamp != most_recent)
+ .map(|(_, path, lock)| (path, lock))
+ .collect()
+ } else {
+ FxHashMap::default()
+ }
+}
+
+/// Since paths of artifacts within session directories can get quite long, we
+/// need to support deleting files with very long paths. The regular
+/// WinApi functions only support paths up to 260 characters, however. In order
+/// to circumvent this limitation, we canonicalize the path of the directory
+/// before passing it to std::fs::remove_dir_all(). This will convert the path
+/// into the '\\?\' format, which supports much longer paths.
+fn safe_remove_dir_all(p: &Path) -> io::Result<()> {
+ let canonicalized = match std_fs::canonicalize(p) {
+ Ok(canonicalized) => canonicalized,
+ Err(err) if err.kind() == io::ErrorKind::NotFound => return Ok(()),
+ Err(err) => return Err(err),
+ };
+
+ std_fs::remove_dir_all(canonicalized)
+}
+
+fn safe_remove_file(p: &Path) -> io::Result<()> {
+ let canonicalized = match std_fs::canonicalize(p) {
+ Ok(canonicalized) => canonicalized,
+ Err(err) if err.kind() == io::ErrorKind::NotFound => return Ok(()),
+ Err(err) => return Err(err),
+ };
+
+ match std_fs::remove_file(canonicalized) {
+ Err(err) if err.kind() == io::ErrorKind::NotFound => Ok(()),
+ result => result,
+ }
+}
+
+// On Windows the compiler would sometimes fail to rename the session directory because
+// the OS thought something was still being accessed in it. So we retry a few times to give
+// the OS time to catch up.
+// See https://github.com/rust-lang/rust/issues/86929.
+fn rename_path_with_retry(from: &Path, to: &Path, mut retries_left: usize) -> std::io::Result<()> {
+ loop {
+ match std_fs::rename(from, to) {
+ Ok(()) => return Ok(()),
+ Err(e) => {
+ if retries_left > 0 && e.kind() == ErrorKind::PermissionDenied {
+ // Try again after a short waiting period.
+ std::thread::sleep(Duration::from_millis(50));
+ retries_left -= 1;
+ } else {
+ return Err(e);
+ }
+ }
+ }
+ }
+}
diff --git a/compiler/rustc_incremental/src/persist/fs/tests.rs b/compiler/rustc_incremental/src/persist/fs/tests.rs
new file mode 100644
index 000000000..184796948
--- /dev/null
+++ b/compiler/rustc_incremental/src/persist/fs/tests.rs
@@ -0,0 +1,84 @@
+use super::*;
+
+#[test]
+fn test_all_except_most_recent() {
+ assert_eq!(
+ all_except_most_recent(vec![
+ (UNIX_EPOCH + Duration::new(4, 0), PathBuf::from("4"), None),
+ (UNIX_EPOCH + Duration::new(1, 0), PathBuf::from("1"), None),
+ (UNIX_EPOCH + Duration::new(5, 0), PathBuf::from("5"), None),
+ (UNIX_EPOCH + Duration::new(3, 0), PathBuf::from("3"), None),
+ (UNIX_EPOCH + Duration::new(2, 0), PathBuf::from("2"), None),
+ ])
+ .keys()
+ .cloned()
+ .collect::<FxHashSet<PathBuf>>(),
+ [PathBuf::from("1"), PathBuf::from("2"), PathBuf::from("3"), PathBuf::from("4"),]
+ .into_iter()
+ .collect::<FxHashSet<PathBuf>>()
+ );
+
+ assert_eq!(
+ all_except_most_recent(vec![]).keys().cloned().collect::<FxHashSet<PathBuf>>(),
+ FxHashSet::default()
+ );
+}
+
+#[test]
+fn test_timestamp_serialization() {
+ for i in 0..1_000u64 {
+ let time = UNIX_EPOCH + Duration::new(i * 1_434_578, (i as u32) * 239_000);
+ let s = timestamp_to_string(time);
+ assert_eq!(Ok(time), string_to_timestamp(&s));
+ }
+}
+
+#[test]
+fn test_find_source_directory_in_iter() {
+ let already_visited = FxHashSet::default();
+
+ // Find newest
+ assert_eq!(
+ find_source_directory_in_iter(
+ [
+ PathBuf::from("crate-dir/s-3234-0000-svh"),
+ PathBuf::from("crate-dir/s-2234-0000-svh"),
+ PathBuf::from("crate-dir/s-1234-0000-svh")
+ ]
+ .into_iter(),
+ &already_visited
+ ),
+ Some(PathBuf::from("crate-dir/s-3234-0000-svh"))
+ );
+
+ // Filter out "-working"
+ assert_eq!(
+ find_source_directory_in_iter(
+ [
+ PathBuf::from("crate-dir/s-3234-0000-working"),
+ PathBuf::from("crate-dir/s-2234-0000-svh"),
+ PathBuf::from("crate-dir/s-1234-0000-svh")
+ ]
+ .into_iter(),
+ &already_visited
+ ),
+ Some(PathBuf::from("crate-dir/s-2234-0000-svh"))
+ );
+
+ // Handle empty
+ assert_eq!(find_source_directory_in_iter([].into_iter(), &already_visited), None);
+
+ // Handle only working
+ assert_eq!(
+ find_source_directory_in_iter(
+ [
+ PathBuf::from("crate-dir/s-3234-0000-working"),
+ PathBuf::from("crate-dir/s-2234-0000-working"),
+ PathBuf::from("crate-dir/s-1234-0000-working")
+ ]
+ .into_iter(),
+ &already_visited
+ ),
+ None
+ );
+}
diff --git a/compiler/rustc_incremental/src/persist/load.rs b/compiler/rustc_incremental/src/persist/load.rs
new file mode 100644
index 000000000..1c5fd9169
--- /dev/null
+++ b/compiler/rustc_incremental/src/persist/load.rs
@@ -0,0 +1,235 @@
+//! Code to save/load the dep-graph from files.
+
+use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::memmap::Mmap;
+use rustc_middle::dep_graph::{SerializedDepGraph, WorkProduct, WorkProductId};
+use rustc_middle::ty::OnDiskCache;
+use rustc_serialize::opaque::MemDecoder;
+use rustc_serialize::Decodable;
+use rustc_session::config::IncrementalStateAssertion;
+use rustc_session::Session;
+use std::path::Path;
+
+use super::data::*;
+use super::file_format;
+use super::fs::*;
+use super::work_product;
+
+type WorkProductMap = FxHashMap<WorkProductId, WorkProduct>;
+
+#[derive(Debug)]
+/// Represents the result of an attempt to load incremental compilation data.
+pub enum LoadResult<T> {
+ /// Loading was successful.
+ Ok {
+ #[allow(missing_docs)]
+ data: T,
+ },
+ /// The file either didn't exist or was produced by an incompatible compiler version.
+ DataOutOfDate,
+ /// An error occurred.
+ Error {
+ #[allow(missing_docs)]
+ message: String,
+ },
+}
+
+impl<T: Default> LoadResult<T> {
+ /// Accesses the data returned in [`LoadResult::Ok`].
+ pub fn open(self, sess: &Session) -> T {
+ // Check for errors when using `-Zassert-incremental-state`
+ match (sess.opts.assert_incr_state, &self) {
+ (Some(IncrementalStateAssertion::NotLoaded), LoadResult::Ok { .. }) => {
+ sess.fatal(
+ "We asserted that the incremental cache should not be loaded, \
+ but it was loaded.",
+ );
+ }
+ (
+ Some(IncrementalStateAssertion::Loaded),
+ LoadResult::Error { .. } | LoadResult::DataOutOfDate,
+ ) => {
+ sess.fatal(
+ "We asserted that an existing incremental cache directory should \
+ be successfully loaded, but it was not.",
+ );
+ }
+ _ => {}
+ };
+
+ match self {
+ LoadResult::Error { message } => {
+ sess.warn(&message);
+ Default::default()
+ }
+ LoadResult::DataOutOfDate => {
+ if let Err(err) = delete_all_session_dir_contents(sess) {
+ sess.err(&format!(
+ "Failed to delete invalidated or incompatible \
+ incremental compilation session directory contents `{}`: {}.",
+ dep_graph_path(sess).display(),
+ err
+ ));
+ }
+ Default::default()
+ }
+ LoadResult::Ok { data } => data,
+ }
+ }
+}
+
+fn load_data(
+ report_incremental_info: bool,
+ path: &Path,
+ nightly_build: bool,
+) -> LoadResult<(Mmap, usize)> {
+ match file_format::read_file(report_incremental_info, path, nightly_build) {
+ Ok(Some(data_and_pos)) => LoadResult::Ok { data: data_and_pos },
+ Ok(None) => {
+ // The file either didn't exist or was produced by an incompatible
+ // compiler version. Neither is an error.
+ LoadResult::DataOutOfDate
+ }
+ Err(err) => LoadResult::Error {
+ message: format!("could not load dep-graph from `{}`: {}", path.display(), err),
+ },
+ }
+}
+
+fn delete_dirty_work_product(sess: &Session, swp: SerializedWorkProduct) {
+ debug!("delete_dirty_work_product({:?})", swp);
+ work_product::delete_workproduct_files(sess, &swp.work_product);
+}
+
+/// Either a result that has already be computed or a
+/// handle that will let us wait until it is computed
+/// by a background thread.
+pub enum MaybeAsync<T> {
+ Sync(T),
+ Async(std::thread::JoinHandle<T>),
+}
+
+impl<T> MaybeAsync<LoadResult<T>> {
+ /// Accesses the data returned in [`LoadResult::Ok`] in an asynchronous way if possible.
+ pub fn open(self) -> LoadResult<T> {
+ match self {
+ MaybeAsync::Sync(result) => result,
+ MaybeAsync::Async(handle) => handle.join().unwrap_or_else(|e| LoadResult::Error {
+ message: format!("could not decode incremental cache: {:?}", e),
+ }),
+ }
+ }
+}
+
+/// An asynchronous type for computing the dependency graph.
+pub type DepGraphFuture = MaybeAsync<LoadResult<(SerializedDepGraph, WorkProductMap)>>;
+
+/// Launch a thread and load the dependency graph in the background.
+pub fn load_dep_graph(sess: &Session) -> DepGraphFuture {
+ // Since `sess` isn't `Sync`, we perform all accesses to `sess`
+ // before we fire the background thread.
+
+ let prof = sess.prof.clone();
+
+ if sess.opts.incremental.is_none() {
+ // No incremental compilation.
+ return MaybeAsync::Sync(LoadResult::Ok { data: Default::default() });
+ }
+
+ let _timer = sess.prof.generic_activity("incr_comp_prepare_load_dep_graph");
+
+ // Calling `sess.incr_comp_session_dir()` will panic if `sess.opts.incremental.is_none()`.
+ // Fortunately, we just checked that this isn't the case.
+ let path = dep_graph_path(&sess);
+ let report_incremental_info = sess.opts.unstable_opts.incremental_info;
+ let expected_hash = sess.opts.dep_tracking_hash(false);
+
+ let mut prev_work_products = FxHashMap::default();
+ let nightly_build = sess.is_nightly_build();
+
+ // If we are only building with -Zquery-dep-graph but without an actual
+ // incr. comp. session directory, we skip this. Otherwise we'd fail
+ // when trying to load work products.
+ if sess.incr_comp_session_dir_opt().is_some() {
+ let work_products_path = work_products_path(sess);
+ let load_result = load_data(report_incremental_info, &work_products_path, nightly_build);
+
+ if let LoadResult::Ok { data: (work_products_data, start_pos) } = load_result {
+ // Decode the list of work_products
+ let mut work_product_decoder = MemDecoder::new(&work_products_data[..], start_pos);
+ let work_products: Vec<SerializedWorkProduct> =
+ Decodable::decode(&mut work_product_decoder);
+
+ for swp in work_products {
+ let all_files_exist = swp.work_product.saved_files.iter().all(|(_, path)| {
+ let exists = in_incr_comp_dir_sess(sess, path).exists();
+ if !exists && sess.opts.unstable_opts.incremental_info {
+ eprintln!("incremental: could not find file for work product: {path}",);
+ }
+ exists
+ });
+
+ if all_files_exist {
+ debug!("reconcile_work_products: all files for {:?} exist", swp);
+ prev_work_products.insert(swp.id, swp.work_product);
+ } else {
+ debug!("reconcile_work_products: some file for {:?} does not exist", swp);
+ delete_dirty_work_product(sess, swp);
+ }
+ }
+ }
+ }
+
+ MaybeAsync::Async(std::thread::spawn(move || {
+ let _prof_timer = prof.generic_activity("incr_comp_load_dep_graph");
+
+ match load_data(report_incremental_info, &path, nightly_build) {
+ LoadResult::DataOutOfDate => LoadResult::DataOutOfDate,
+ LoadResult::Error { message } => LoadResult::Error { message },
+ LoadResult::Ok { data: (bytes, start_pos) } => {
+ let mut decoder = MemDecoder::new(&bytes, start_pos);
+ let prev_commandline_args_hash = u64::decode(&mut decoder);
+
+ if prev_commandline_args_hash != expected_hash {
+ if report_incremental_info {
+ eprintln!(
+ "[incremental] completely ignoring cache because of \
+ differing commandline arguments"
+ );
+ }
+ // We can't reuse the cache, purge it.
+ debug!("load_dep_graph_new: differing commandline arg hashes");
+
+ // No need to do any further work
+ return LoadResult::DataOutOfDate;
+ }
+
+ let dep_graph = SerializedDepGraph::decode(&mut decoder);
+
+ LoadResult::Ok { data: (dep_graph, prev_work_products) }
+ }
+ }
+ }))
+}
+
+/// Attempts to load the query result cache from disk
+///
+/// If we are not in incremental compilation mode, returns `None`.
+/// Otherwise, tries to load the query result cache from disk,
+/// creating an empty cache if it could not be loaded.
+pub fn load_query_result_cache<'a, C: OnDiskCache<'a>>(sess: &'a Session) -> Option<C> {
+ if sess.opts.incremental.is_none() {
+ return None;
+ }
+
+ let _prof_timer = sess.prof.generic_activity("incr_comp_load_query_result_cache");
+
+ match load_data(
+ sess.opts.unstable_opts.incremental_info,
+ &query_cache_path(sess),
+ sess.is_nightly_build(),
+ ) {
+ LoadResult::Ok { data: (bytes, start_pos) } => Some(C::new(sess, bytes, start_pos)),
+ _ => Some(C::new_empty(sess.source_map())),
+ }
+}
diff --git a/compiler/rustc_incremental/src/persist/mod.rs b/compiler/rustc_incremental/src/persist/mod.rs
new file mode 100644
index 000000000..1336189bc
--- /dev/null
+++ b/compiler/rustc_incremental/src/persist/mod.rs
@@ -0,0 +1,25 @@
+//! When in incremental mode, this pass dumps out the dependency graph
+//! into the given directory. At the same time, it also hashes the
+//! various HIR nodes.
+
+mod data;
+mod dirty_clean;
+mod file_format;
+mod fs;
+mod load;
+mod save;
+mod work_product;
+
+pub use fs::finalize_session_directory;
+pub use fs::garbage_collect_session_directories;
+pub use fs::in_incr_comp_dir;
+pub use fs::in_incr_comp_dir_sess;
+pub use fs::prepare_session_directory;
+pub use load::load_query_result_cache;
+pub use load::LoadResult;
+pub use load::{load_dep_graph, DepGraphFuture};
+pub use save::build_dep_graph;
+pub use save::save_dep_graph;
+pub use save::save_work_product_index;
+pub use work_product::copy_cgu_workproduct_to_incr_comp_cache_dir;
+pub use work_product::delete_workproduct_files;
diff --git a/compiler/rustc_incremental/src/persist/save.rs b/compiler/rustc_incremental/src/persist/save.rs
new file mode 100644
index 000000000..710350314
--- /dev/null
+++ b/compiler/rustc_incremental/src/persist/save.rs
@@ -0,0 +1,188 @@
+use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::sync::join;
+use rustc_middle::dep_graph::{DepGraph, SerializedDepGraph, WorkProduct, WorkProductId};
+use rustc_middle::ty::TyCtxt;
+use rustc_serialize::opaque::{FileEncodeResult, FileEncoder};
+use rustc_serialize::Encodable as RustcEncodable;
+use rustc_session::Session;
+use std::fs;
+
+use super::data::*;
+use super::dirty_clean;
+use super::file_format;
+use super::fs::*;
+use super::work_product;
+
+/// Saves and writes the [`DepGraph`] to the file system.
+///
+/// This function saves both the dep-graph and the query result cache,
+/// and drops the result cache.
+///
+/// This function should only run after all queries have completed.
+/// Trying to execute a query afterwards would attempt to read the result cache we just dropped.
+pub fn save_dep_graph(tcx: TyCtxt<'_>) {
+ debug!("save_dep_graph()");
+ tcx.dep_graph.with_ignore(|| {
+ let sess = tcx.sess;
+ if sess.opts.incremental.is_none() {
+ return;
+ }
+ // This is going to be deleted in finalize_session_directory, so let's not create it
+ if sess.has_errors_or_delayed_span_bugs() {
+ return;
+ }
+
+ let query_cache_path = query_cache_path(sess);
+ let dep_graph_path = dep_graph_path(sess);
+ let staging_dep_graph_path = staging_dep_graph_path(sess);
+
+ sess.time("assert_dep_graph", || crate::assert_dep_graph(tcx));
+ sess.time("check_dirty_clean", || dirty_clean::check_dirty_clean_annotations(tcx));
+
+ if sess.opts.unstable_opts.incremental_info {
+ tcx.dep_graph.print_incremental_info()
+ }
+
+ join(
+ move || {
+ sess.time("incr_comp_persist_result_cache", || {
+ // Drop the memory map so that we can remove the file and write to it.
+ if let Some(odc) = &tcx.on_disk_cache {
+ odc.drop_serialized_data(tcx);
+ }
+
+ file_format::save_in(sess, query_cache_path, "query cache", |e| {
+ encode_query_cache(tcx, e)
+ });
+ });
+ },
+ move || {
+ sess.time("incr_comp_persist_dep_graph", || {
+ if let Err(err) = tcx.dep_graph.encode(&tcx.sess.prof) {
+ sess.err(&format!(
+ "failed to write dependency graph to `{}`: {}",
+ staging_dep_graph_path.display(),
+ err
+ ));
+ }
+ if let Err(err) = fs::rename(&staging_dep_graph_path, &dep_graph_path) {
+ sess.err(&format!(
+ "failed to move dependency graph from `{}` to `{}`: {}",
+ staging_dep_graph_path.display(),
+ dep_graph_path.display(),
+ err
+ ));
+ }
+ });
+ },
+ );
+ })
+}
+
+/// Saves the work product index.
+pub fn save_work_product_index(
+ sess: &Session,
+ dep_graph: &DepGraph,
+ new_work_products: FxHashMap<WorkProductId, WorkProduct>,
+) {
+ if sess.opts.incremental.is_none() {
+ return;
+ }
+ // This is going to be deleted in finalize_session_directory, so let's not create it
+ if sess.has_errors_or_delayed_span_bugs() {
+ return;
+ }
+
+ debug!("save_work_product_index()");
+ dep_graph.assert_ignored();
+ let path = work_products_path(sess);
+ file_format::save_in(sess, path, "work product index", |mut e| {
+ encode_work_product_index(&new_work_products, &mut e);
+ e.finish()
+ });
+
+ // We also need to clean out old work-products, as not all of them are
+ // deleted during invalidation. Some object files don't change their
+ // content, they are just not needed anymore.
+ let previous_work_products = dep_graph.previous_work_products();
+ for (id, wp) in previous_work_products.iter() {
+ if !new_work_products.contains_key(id) {
+ work_product::delete_workproduct_files(sess, wp);
+ debug_assert!(
+ !wp.saved_files.iter().all(|(_, path)| in_incr_comp_dir_sess(sess, path).exists())
+ );
+ }
+ }
+
+ // Check that we did not delete one of the current work-products:
+ debug_assert!({
+ new_work_products.iter().all(|(_, wp)| {
+ wp.saved_files.iter().all(|(_, path)| in_incr_comp_dir_sess(sess, path).exists())
+ })
+ });
+}
+
+fn encode_work_product_index(
+ work_products: &FxHashMap<WorkProductId, WorkProduct>,
+ encoder: &mut FileEncoder,
+) {
+ let serialized_products: Vec<_> = work_products
+ .iter()
+ .map(|(id, work_product)| SerializedWorkProduct {
+ id: *id,
+ work_product: work_product.clone(),
+ })
+ .collect();
+
+ serialized_products.encode(encoder)
+}
+
+fn encode_query_cache(tcx: TyCtxt<'_>, encoder: FileEncoder) -> FileEncodeResult {
+ tcx.sess.time("incr_comp_serialize_result_cache", || tcx.serialize_query_result_cache(encoder))
+}
+
+/// Builds the dependency graph.
+///
+/// This function creates the *staging dep-graph*. When the dep-graph is modified by a query
+/// execution, the new dependency information is not kept in memory but directly
+/// output to this file. `save_dep_graph` then finalizes the staging dep-graph
+/// and moves it to the permanent dep-graph path
+pub fn build_dep_graph(
+ sess: &Session,
+ prev_graph: SerializedDepGraph,
+ prev_work_products: FxHashMap<WorkProductId, WorkProduct>,
+) -> Option<DepGraph> {
+ if sess.opts.incremental.is_none() {
+ // No incremental compilation.
+ return None;
+ }
+
+ // Stream the dep-graph to an alternate file, to avoid overwriting anything in case of errors.
+ let path_buf = staging_dep_graph_path(sess);
+
+ let mut encoder = match FileEncoder::new(&path_buf) {
+ Ok(encoder) => encoder,
+ Err(err) => {
+ sess.err(&format!(
+ "failed to create dependency graph at `{}`: {}",
+ path_buf.display(),
+ err
+ ));
+ return None;
+ }
+ };
+
+ file_format::write_file_header(&mut encoder, sess.is_nightly_build());
+
+ // First encode the commandline arguments hash
+ sess.opts.dep_tracking_hash(false).encode(&mut encoder);
+
+ Some(DepGraph::new(
+ &sess.prof,
+ prev_graph,
+ prev_work_products,
+ encoder,
+ sess.opts.unstable_opts.query_dep_graph,
+ sess.opts.unstable_opts.incremental_info,
+ ))
+}
diff --git a/compiler/rustc_incremental/src/persist/work_product.rs b/compiler/rustc_incremental/src/persist/work_product.rs
new file mode 100644
index 000000000..2f1853c44
--- /dev/null
+++ b/compiler/rustc_incremental/src/persist/work_product.rs
@@ -0,0 +1,59 @@
+//! Functions for saving and removing intermediate [work products].
+//!
+//! [work products]: WorkProduct
+
+use crate::persist::fs::*;
+use rustc_data_structures::fx::FxHashMap;
+use rustc_fs_util::link_or_copy;
+use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
+use rustc_session::Session;
+use std::fs as std_fs;
+use std::path::Path;
+
+/// Copies a CGU work product to the incremental compilation directory, so next compilation can find and reuse it.
+pub fn copy_cgu_workproduct_to_incr_comp_cache_dir(
+ sess: &Session,
+ cgu_name: &str,
+ files: &[(&'static str, &Path)],
+) -> Option<(WorkProductId, WorkProduct)> {
+ debug!(?cgu_name, ?files);
+ sess.opts.incremental.as_ref()?;
+
+ let mut saved_files = FxHashMap::default();
+ for (ext, path) in files {
+ let file_name = format!("{cgu_name}.{ext}");
+ let path_in_incr_dir = in_incr_comp_dir_sess(sess, &file_name);
+ match link_or_copy(path, &path_in_incr_dir) {
+ Ok(_) => {
+ let _ = saved_files.insert(ext.to_string(), file_name);
+ }
+ Err(err) => {
+ sess.warn(&format!(
+ "error copying object file `{}` to incremental directory as `{}`: {}",
+ path.display(),
+ path_in_incr_dir.display(),
+ err
+ ));
+ }
+ }
+ }
+
+ let work_product = WorkProduct { cgu_name: cgu_name.to_string(), saved_files };
+ debug!(?work_product);
+ let work_product_id = WorkProductId::from_cgu_name(cgu_name);
+ Some((work_product_id, work_product))
+}
+
+/// Removes files for a given work product.
+pub fn delete_workproduct_files(sess: &Session, work_product: &WorkProduct) {
+ for (_, path) in &work_product.saved_files {
+ let path = in_incr_comp_dir_sess(sess, path);
+ if let Err(err) = std_fs::remove_file(&path) {
+ sess.warn(&format!(
+ "file-system error deleting outdated file `{}`: {}",
+ path.display(),
+ err
+ ));
+ }
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-19 15:05:18 +0000