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Make DepGraph::previous_work_products immutable
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Fixes #50501
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@wesleywiser
wesleywiser committed May 8, 2018
1 parent 565235e commit 000d3c9
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Showing 3 changed files with 74 additions and 83 deletions.
26 changes: 7 additions & 19 deletions src/librustc/dep_graph/graph.rs
View file
Expand Up @@ -77,7 +77,7 @@ struct DepGraphData {
/// things available to us. If we find that they are not dirty, we
/// load the path to the file storing those work-products here into
/// this map. We can later look for and extract that data.
previous_work_products: RwLock<FxHashMap<WorkProductId, WorkProduct>>,
previous_work_products: FxHashMap<WorkProductId, WorkProduct>,

/// Work-products that we generate in this run.
work_products: RwLock<FxHashMap<WorkProductId, WorkProduct>>,
Expand All @@ -90,7 +90,8 @@ struct DepGraphData {

impl DepGraph {

pub fn new(prev_graph: PreviousDepGraph) -> DepGraph {
pub fn new(prev_graph: PreviousDepGraph,
prev_work_products: FxHashMap<WorkProductId, WorkProduct>) -> DepGraph {
// Pre-allocate the fingerprints array. We over-allocate a little so
// that we hopefully don't have to re-allocate during this compilation
// session.
Expand All @@ -100,7 +101,7 @@ impl DepGraph {
(prev_graph_node_count * 115) / 100);
DepGraph {
data: Some(Lrc::new(DepGraphData {
previous_work_products: RwLock::new(FxHashMap()),
previous_work_products: prev_work_products,
work_products: RwLock::new(FxHashMap()),
dep_node_debug: Lock::new(FxHashMap()),
current: Lock::new(CurrentDepGraph::new()),
Expand Down Expand Up @@ -460,19 +461,6 @@ impl DepGraph {
self.data.as_ref().unwrap().previous.node_to_index(dep_node)
}

/// Indicates that a previous work product exists for `v`. This is
/// invoked during initial start-up based on what nodes are clean
/// (and what files exist in the incr. directory).
pub fn insert_previous_work_product(&self, v: &WorkProductId, data: WorkProduct) {
debug!("insert_previous_work_product({:?}, {:?})", v, data);
self.data
.as_ref()
.unwrap()
.previous_work_products
.borrow_mut()
.insert(v.clone(), data);
}

/// Indicates that we created the given work-product in this run
/// for `v`. This record will be preserved and loaded in the next
/// run.
Expand All @@ -492,7 +480,7 @@ impl DepGraph {
self.data
.as_ref()
.and_then(|data| {
data.previous_work_products.borrow().get(v).cloned()
data.previous_work_products.get(v).cloned()
})
}

Expand All @@ -504,8 +492,8 @@ impl DepGraph {

/// Access the map of work-products created during the cached run. Only
/// used during saving of the dep-graph.
pub fn previous_work_products(&self) -> ReadGuard<FxHashMap<WorkProductId, WorkProduct>> {
self.data.as_ref().unwrap().previous_work_products.borrow()
pub fn previous_work_products(&self) -> &FxHashMap<WorkProductId, WorkProduct> {
&self.data.as_ref().unwrap().previous_work_products
}

#[inline(always)]
Expand Down
19 changes: 10 additions & 9 deletions src/librustc_driver/driver.rs
View file
Expand Up @@ -980,15 +980,16 @@ where
let dep_graph = match future_dep_graph {
None => DepGraph::new_disabled(),
Some(future) => {
let prev_graph = time(sess, "blocked while dep-graph loading finishes", || {
future
.open()
.unwrap_or_else(|e| rustc_incremental::LoadResult::Error {
message: format!("could not decode incremental cache: {:?}", e),
})
.open(sess)
});
DepGraph::new(prev_graph)
let (prev_graph, prev_work_products) =
time(sess, "blocked while dep-graph loading finishes", || {
future
.open()
.unwrap_or_else(|e| rustc_incremental::LoadResult::Error {
message: format!("could not decode incremental cache: {:?}", e),
})
.open(sess)
});
DepGraph::new(prev_graph, prev_work_products)
}
};
let hir_forest = time(sess, "lowering ast -> hir", || {
Expand Down
112 changes: 57 additions & 55 deletions src/librustc_incremental/persist/load.rs
View file
Expand Up @@ -10,7 +10,8 @@

//! Code to save/load the dep-graph from files.

use rustc::dep_graph::{PreviousDepGraph, SerializedDepGraph};
use rustc_data_structures::fx::FxHashMap;
use rustc::dep_graph::{PreviousDepGraph, SerializedDepGraph, WorkProduct, WorkProductId};
use rustc::session::Session;
use rustc::ty::TyCtxt;
use rustc::ty::maps::OnDiskCache;
Expand All @@ -32,73 +33,30 @@ pub fn dep_graph_tcx_init<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {

tcx.allocate_metadata_dep_nodes();
tcx.precompute_in_scope_traits_hashes();

if tcx.sess.incr_comp_session_dir_opt().is_none() {
// If we are only building with -Zquery-dep-graph but without an actual
// incr. comp. session directory, we exit here. Otherwise we'd fail
// when trying to load work products.
return
}

let work_products_path = work_products_path(tcx.sess);
let load_result = load_data(tcx.sess.opts.debugging_opts.incremental_info, &work_products_path);

if let LoadResult::Ok { data: (work_products_data, start_pos) } = load_result {
// Decode the list of work_products
let mut work_product_decoder = Decoder::new(&work_products_data[..], start_pos);
let work_products: Vec<SerializedWorkProduct> =
RustcDecodable::decode(&mut work_product_decoder).unwrap_or_else(|e| {
let msg = format!("Error decoding `work-products` from incremental \
compilation session directory: {}", e);
tcx.sess.fatal(&msg[..])
});

for swp in work_products {
let mut all_files_exist = true;
for &(_, ref file_name) in swp.work_product.saved_files.iter() {
let path = in_incr_comp_dir_sess(tcx.sess, file_name);
if !path.exists() {
all_files_exist = false;

if tcx.sess.opts.debugging_opts.incremental_info {
eprintln!("incremental: could not find file for work \
product: {}", path.display());
}
}
}

if all_files_exist {
debug!("reconcile_work_products: all files for {:?} exist", swp);
tcx.dep_graph.insert_previous_work_product(&swp.id, swp.work_product);
} else {
debug!("reconcile_work_products: some file for {:?} does not exist", swp);
delete_dirty_work_product(tcx, swp);
}
}
}
}

type WorkProductMap = FxHashMap<WorkProductId, WorkProduct>;

pub enum LoadResult<T> {
Ok { data: T },
DataOutOfDate,
Error { message: String },
}


impl LoadResult<PreviousDepGraph> {
pub fn open(self, sess: &Session) -> PreviousDepGraph {
impl LoadResult<(PreviousDepGraph, WorkProductMap)> {
pub fn open(self, sess: &Session) -> (PreviousDepGraph, WorkProductMap) {
match self {
LoadResult::Error { message } => {
sess.warn(&message);
PreviousDepGraph::new(SerializedDepGraph::new())
(PreviousDepGraph::new(SerializedDepGraph::new()), FxHashMap())
},
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));
}
PreviousDepGraph::new(SerializedDepGraph::new())
(PreviousDepGraph::new(SerializedDepGraph::new()), FxHashMap())
}
LoadResult::Ok { data } => data
}
Expand All @@ -125,10 +83,10 @@ fn load_data(report_incremental_info: bool, path: &Path) -> LoadResult<(Vec<u8>,
}
}

fn delete_dirty_work_product(tcx: TyCtxt,
fn delete_dirty_work_product(sess: &Session,
swp: SerializedWorkProduct) {
debug!("delete_dirty_work_product({:?})", swp);
work_product::delete_workproduct_files(tcx.sess, &swp.work_product);
work_product::delete_workproduct_files(sess, &swp.work_product);
}

/// Either a result that has already be computed or a
Expand All @@ -149,7 +107,7 @@ impl<T> MaybeAsync<T> {

/// Launch a thread and load the dependency graph in the background.
pub fn load_dep_graph(sess: &Session) ->
MaybeAsync<LoadResult<PreviousDepGraph>>
MaybeAsync<LoadResult<(PreviousDepGraph, WorkProductMap)>>
{
// Since `sess` isn't `Sync`, we perform all accesses to `sess`
// before we fire the background thread.
Expand All @@ -159,7 +117,7 @@ pub fn load_dep_graph(sess: &Session) ->
if sess.opts.incremental.is_none() {
// No incremental compilation.
return MaybeAsync::Sync(LoadResult::Ok {
data: PreviousDepGraph::new(SerializedDepGraph::new())
data: (PreviousDepGraph::new(SerializedDepGraph::new()), FxHashMap())
});
}

Expand All @@ -169,6 +127,50 @@ pub fn load_dep_graph(sess: &Session) ->
let report_incremental_info = sess.opts.debugging_opts.incremental_info;
let expected_hash = sess.opts.dep_tracking_hash();

let mut prev_work_products = FxHashMap();

// If we are only building with -Zquery-dep-graph but without an actual
// incr. comp. session directory, we exit here. 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);

if let LoadResult::Ok { data: (work_products_data, start_pos) } = load_result {
// Decode the list of work_products
let mut work_product_decoder = Decoder::new(&work_products_data[..], start_pos);
let work_products: Vec<SerializedWorkProduct> =
RustcDecodable::decode(&mut work_product_decoder).unwrap_or_else(|e| {
let msg = format!("Error decoding `work-products` from incremental \
compilation session directory: {}", e);
sess.fatal(&msg[..])
});

for swp in work_products {
let mut all_files_exist = true;
for &(_, ref file_name) in swp.work_product.saved_files.iter() {
let path = in_incr_comp_dir_sess(sess, file_name);
if !path.exists() {
all_files_exist = false;

if sess.opts.debugging_opts.incremental_info {
eprintln!("incremental: could not find file for work \
product: {}", path.display());
}
}
}

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 || {
time_ext(time_passes, None, "background load prev dep-graph", move || {
match load_data(report_incremental_info, &path) {
Expand All @@ -195,7 +197,7 @@ pub fn load_dep_graph(sess: &Session) ->
let dep_graph = SerializedDepGraph::decode(&mut decoder)
.expect("Error reading cached dep-graph");

LoadResult::Ok { data: PreviousDepGraph::new(dep_graph) }
LoadResult::Ok { data: (PreviousDepGraph::new(dep_graph), prev_work_products) }
}
}
})
Expand Down

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