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Don't hash span filenames twice in IchHasher.

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This significantly reduces the number of bytes hashed by IchHasher.
This commit is contained in:
Nicholas Nethercote 2016-10-27 09:06:31 +11:00
parent 4497196ba5
commit af0b27e01f
1 changed files with 31 additions and 11 deletions
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42
src/librustc_incremental/calculate_svh/svh_visitor.rs
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@ -82,6 +82,8 @@ impl<'a, 'hash, 'tcx> StrictVersionHashVisitor<'a, 'hash, 'tcx> {
// within the CodeMap.
// Also note that we are hashing byte offsets for the column, not unicode
// codepoint offsets. For the purpose of the hash that's sufficient.
// Also, hashing filenames is expensive so we avoid doing it twice when the
// span starts and ends in the same file, which is almost always the case.
fn hash_span(&mut self, span: Span) {
debug_assert!(self.hash_spans);
debug!("hash_span: st={:?}", self.st);
@ -98,21 +100,35 @@ impl<'a, 'hash, 'tcx> StrictVersionHashVisitor<'a, 'hash, 'tcx> {
span.hi
};
let loc1 = self.codemap.byte_pos_to_line_and_col(span.lo);
let loc2 = self.codemap.byte_pos_to_line_and_col(span_hi);
let expansion_kind = match span.expn_id {
let expn_kind = match span.expn_id {
NO_EXPANSION => SawSpanExpnKind::NoExpansion,
COMMAND_LINE_EXPN => SawSpanExpnKind::CommandLine,
_ => SawSpanExpnKind::SomeExpansion,
};
SawSpan(loc1.as_ref().map(|&(ref fm, line, col)| (&fm.name[..], line, col)),
loc2.as_ref().map(|&(ref fm, line, col)| (&fm.name[..], line, col)),
expansion_kind)
.hash(self.st);
let loc1 = self.codemap.byte_pos_to_line_and_col(span.lo);
let loc1 = loc1.as_ref()
.map(|&(ref fm, line, col)| (&fm.name[..], line, col))
.unwrap_or(("???", 0, BytePos(0)));
if expansion_kind == SawSpanExpnKind::SomeExpansion {
let loc2 = self.codemap.byte_pos_to_line_and_col(span_hi);
let loc2 = loc2.as_ref()
.map(|&(ref fm, line, col)| (&fm.name[..], line, col))
.unwrap_or(("???", 0, BytePos(0)));
let saw = if loc1.0 == loc2.0 {
SawSpan(loc1.0,
loc1.1, loc1.2,
loc2.1, loc2.2,
expn_kind)
} else {
SawSpanTwoFiles(loc1.0, loc1.1, loc1.2,
loc2.0, loc2.1, loc2.2,
expn_kind)
};
saw.hash(self.st);
if expn_kind == SawSpanExpnKind::SomeExpansion {
let call_site = self.codemap.codemap().source_callsite(span);
self.hash_span(call_site);
}
@ -184,9 +200,13 @@ enum SawAbiComponent<'a> {
SawAssocTypeBinding,
SawAttribute(ast::AttrStyle),
SawMacroDef,
SawSpan(Option<(&'a str, usize, BytePos)>,
Option<(&'a str, usize, BytePos)>,
SawSpan(&'a str,
usize, BytePos,
usize, BytePos,
SawSpanExpnKind),
SawSpanTwoFiles(&'a str, usize, BytePos,
&'a str, usize, BytePos,
SawSpanExpnKind),
}
/// SawExprComponent carries all of the information that we want