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ICH: Fix codemap lookup caching.

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This commit is contained in:
Michael Woerister 2016-08-31 16:29:04 -04:00
parent a142d2ff02
commit 2faca22bd3
1 changed files with 52 additions and 42 deletions
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94
src/librustc_incremental/calculate_svh/svh_visitor.rs
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@ -43,72 +43,82 @@ pub struct StrictVersionHashVisitor<'a, 'hash: 'a, 'tcx: 'hash> {
codemap: CachingCodemapView<'tcx>,
}
#[derive(Clone)]
struct CacheEntry {
time_stamp: usize,
line_number: usize,
line_start: BytePos,
line_end: BytePos,
file: Rc<FileMap>,
}
struct CachingCodemapView<'tcx> {
codemap: &'tcx CodeMap,
// Format: (line number, line-start, line-end, file)
line_cache: [(usize, BytePos, BytePos, Rc<FileMap>); 4],
eviction_index: usize,
line_cache: [CacheEntry; 3],
time_stamp: usize,
}
impl<'tcx> CachingCodemapView<'tcx> {
fn new<'a>(tcx: TyCtxt<'a, 'tcx, 'tcx>) -> CachingCodemapView<'tcx> {
let codemap = tcx.sess.codemap();
let first_file = codemap.files.borrow()[0].clone();
let entry = CacheEntry {
time_stamp: 0,
line_number: 0,
line_start: BytePos(0),
line_end: BytePos(0),
file: first_file,
};
CachingCodemapView {
codemap: codemap,
line_cache: [(0, BytePos(0), BytePos(0), first_file.clone()),
(0, BytePos(0), BytePos(0), first_file.clone()),
(0, BytePos(0), BytePos(0), first_file.clone()),
(0, BytePos(0), BytePos(0), first_file.clone())],
eviction_index: 0,
line_cache: [entry.clone(), entry.clone(), entry.clone()],
time_stamp: 0,
}
}
fn byte_pos_to_line_and_col(&mut self,
pos: BytePos)
-> (Rc<FileMap>, usize, BytePos) {
self.time_stamp += 1;
// Check if the position is in one of the cached lines
for &(line, start, end, ref file) in self.line_cache.iter() {
if pos >= start && pos < end {
return (file.clone(), line, pos - start);
}
}
// Check whether we have a cached line in the correct file, so we can
// overwrite it without having to look up the file again.
for &mut (ref mut line,
ref mut start,
ref mut end,
ref file) in self.line_cache.iter_mut() {
if pos >= file.start_pos && pos < file.end_pos {
let line_index = file.lookup_line(pos).unwrap();
let (line_start, line_end) = file.line_bounds(line_index);
// Update the cache entry in place
*line = line_index + 1;
*start = line_start;
*end = line_end;
return (file.clone(), line_index + 1, pos - line_start);
for cache_entry in self.line_cache.iter_mut() {
if pos >= cache_entry.line_start && pos < cache_entry.line_end {
cache_entry.time_stamp = self.time_stamp;
return (cache_entry.file.clone(),
cache_entry.line_number,
pos - cache_entry.line_start);
}
}
// No cache hit ...
let file_index = self.codemap.lookup_filemap_idx(pos);
let file = self.codemap.files.borrow()[file_index].clone();
let line_index = file.lookup_line(pos).unwrap();
let (line_start, line_end) = file.line_bounds(line_index);
let mut oldest = 0;
for index in 1 .. self.line_cache.len() {
if self.line_cache[index].time_stamp < self.line_cache[oldest].time_stamp {
oldest = index;
}
}
// Just overwrite some cache entry. If we got this far, all of them
// point to the wrong file.
self.line_cache[self.eviction_index] = (line_index + 1,
line_start,
line_end,
file.clone());
self.eviction_index = (self.eviction_index + 1) % self.line_cache.len();
let cache_entry = &mut self.line_cache[oldest];
return (file, line_index + 1, pos - line_start);
// If the entry doesn't point to the correct file, fix it up
if pos < cache_entry.file.start_pos || pos >= cache_entry.file.end_pos {
let file_index = self.codemap.lookup_filemap_idx(pos);
cache_entry.file = self.codemap.files.borrow()[file_index].clone();
}
let line_index = cache_entry.file.lookup_line(pos).unwrap();
let line_bounds = cache_entry.file.line_bounds(line_index);
cache_entry.line_number = line_index + 1;
cache_entry.line_start = line_bounds.0;
cache_entry.line_end = line_bounds.1;
cache_entry.time_stamp = self.time_stamp;
return (cache_entry.file.clone(),
cache_entry.line_number,
pos - cache_entry.line_start);
}
}