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|
// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! Code to save/load the dep-graph from files.
use rbml::Error;
use rbml::opaque::Decoder;
use rustc::dep_graph::DepNode;
use rustc::hir::def_id::DefId;
use rustc::ty::TyCtxt;
use rustc_data_structures::fnv::FnvHashSet;
use rustc_serialize::Decodable as RustcDecodable;
use std::io::Read;
use std::fs::File;
use std::path::Path;
use super::data::*;
use super::directory::*;
use super::dirty_clean;
use super::hash::*;
use super::util::*;
type DirtyNodes = FnvHashSet<DepNode<DefId>>;
type CleanEdges = Vec<(DepNode<DefId>, DepNode<DefId>)>;
/// If we are in incremental mode, and a previous dep-graph exists,
/// then load up those nodes/edges that are still valid into the
/// dep-graph for this session. (This is assumed to be running very
/// early in compilation, before we've really done any work, but
/// actually it doesn't matter all that much.) See `README.md` for
/// more general overview.
pub fn load_dep_graph<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
let _ignore = tcx.dep_graph.in_ignore();
if let Some(dep_graph) = dep_graph_path(tcx) {
// FIXME(#32754) lock file?
load_dep_graph_if_exists(tcx, &dep_graph);
dirty_clean::check_dirty_clean_annotations(tcx);
}
}
pub fn load_dep_graph_if_exists<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, path: &Path) {
if !path.exists() {
return;
}
let mut data = vec![];
match
File::open(path)
.and_then(|mut file| file.read_to_end(&mut data))
{
Ok(_) => { }
Err(err) => {
tcx.sess.err(
&format!("could not load dep-graph from `{}`: {}",
path.display(), err));
return;
}
}
match decode_dep_graph(tcx, &data) {
Ok(dirty) => dirty,
Err(err) => {
bug!("decoding error in dep-graph from `{}`: {}", path.display(), err);
}
}
}
pub fn decode_dep_graph<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
data: &[u8])
-> Result<(), Error>
{
// Deserialize the directory and dep-graph.
let mut decoder = Decoder::new(data, 0);
let directory = try!(DefIdDirectory::decode(&mut decoder));
let serialized_dep_graph = try!(SerializedDepGraph::decode(&mut decoder));
debug!("decode_dep_graph: directory = {:#?}", directory);
debug!("decode_dep_graph: serialized_dep_graph = {:#?}", serialized_dep_graph);
// Retrace the paths in the directory to find their current location (if any).
let retraced = directory.retrace(tcx);
debug!("decode_dep_graph: retraced = {:#?}", retraced);
// Compute the set of Hir nodes whose data has changed.
let mut dirty_nodes =
initial_dirty_nodes(tcx, &serialized_dep_graph.hashes, &retraced);
debug!("decode_dep_graph: initial dirty_nodes = {:#?}", dirty_nodes);
// Find all DepNodes reachable from that core set. This loop
// iterates repeatedly over the list of edges whose source is not
// known to be dirty (`clean_edges`). If it finds an edge whose
// source is dirty, it removes it from that list and adds the
// target to `dirty_nodes`. It stops when it reaches a fixed
// point.
let clean_edges = compute_clean_edges(&serialized_dep_graph.edges,
&retraced,
&mut dirty_nodes);
// Add synthetic `foo->foo` edges for each clean node `foo` that
// we had before. This is sort of a hack to create clean nodes in
// the graph, since the existence of a node is a signal that the
// work it represents need not be repeated.
let clean_nodes =
serialized_dep_graph.nodes
.iter()
.filter_map(|node| retraced.map(node))
.filter(|node| !dirty_nodes.contains(node))
.map(|node| (node.clone(), node));
// Add nodes and edges that are not dirty into our main graph.
let dep_graph = tcx.dep_graph.clone();
for (source, target) in clean_edges.into_iter().chain(clean_nodes) {
let _task = dep_graph.in_task(target.clone());
dep_graph.read(source.clone());
debug!("decode_dep_graph: clean edge: {:?} -> {:?}", source, target);
}
Ok(())
}
fn initial_dirty_nodes<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
hashes: &[SerializedHash],
retraced: &RetracedDefIdDirectory)
-> DirtyNodes {
let mut hcx = HashContext::new(tcx);
let mut items_removed = false;
let mut dirty_nodes = FnvHashSet();
for hash in hashes {
match hash.node.map_def(|&i| retraced.def_id(i)) {
Some(dep_node) => {
let current_hash = hcx.hash(&dep_node).unwrap();
debug!("initial_dirty_nodes: hash of {:?} is {:?}, was {:?}",
dep_node, current_hash, hash.hash);
if current_hash != hash.hash {
dirty_nodes.insert(dep_node);
}
}
None => {
items_removed = true;
}
}
}
// If any of the items in the krate have changed, then we consider
// the meta-node `Krate` to be dirty, since that means something
// which (potentially) read the contents of every single item.
if items_removed || !dirty_nodes.is_empty() {
dirty_nodes.insert(DepNode::Krate);
}
dirty_nodes
}
fn compute_clean_edges(serialized_edges: &[(SerializedEdge)],
retraced: &RetracedDefIdDirectory,
dirty_nodes: &mut DirtyNodes)
-> CleanEdges {
// Build up an initial list of edges. Include an edge (source,
// target) if neither node has been removed. If the source has
// been removed, add target to the list of dirty nodes.
let mut clean_edges = Vec::with_capacity(serialized_edges.len());
for &(ref serialized_source, ref serialized_target) in serialized_edges {
if let Some(target) = retraced.map(serialized_target) {
if let Some(source) = retraced.map(serialized_source) {
clean_edges.push((source, target))
} else {
// source removed, target must be dirty
dirty_nodes.insert(target);
}
} else {
// target removed, ignore the edge
}
}
debug!("compute_clean_edges: dirty_nodes={:#?}", dirty_nodes);
// Propagate dirty marks by iterating repeatedly over
// `clean_edges`. If we find an edge `(source, target)` where
// `source` is dirty, add `target` to the list of dirty nodes and
// remove it. Keep doing this until we find no more dirty nodes.
let mut previous_size = 0;
while dirty_nodes.len() > previous_size {
debug!("compute_clean_edges: previous_size={}", previous_size);
previous_size = dirty_nodes.len();
let mut i = 0;
while i < clean_edges.len() {
if dirty_nodes.contains(&clean_edges[i].0) {
let (source, target) = clean_edges.swap_remove(i);
debug!("compute_clean_edges: dirty source {:?} -> {:?}",
source, target);
dirty_nodes.insert(target);
} else if dirty_nodes.contains(&clean_edges[i].1) {
let (source, target) = clean_edges.swap_remove(i);
debug!("compute_clean_edges: dirty target {:?} -> {:?}",
source, target);
} else {
i += 1;
}
}
}
clean_edges
}
|
