Auto merge of #86778 - tmiasko:fast-multiline, r=davidtwco

Avoid byte to char position conversions in `is_multiline`

Converting a byte position into a char position is currently linear in
the number of multibyte characters in the source code. Avoid it when
checking if a range spans across lines.

This makes it feasible to compile source files with a large number of
multibyte characters.
This commit is contained in:
bors 2021-07-03 16:06:35 +00:00
commit 96859dbaf6

View File

@ -461,9 +461,13 @@ pub fn span_to_filename(&self, sp: Span) -> FileName {
}
pub fn is_multiline(&self, sp: Span) -> bool {
let lo = self.lookup_char_pos(sp.lo());
let hi = self.lookup_char_pos(sp.hi());
lo.line != hi.line
let lo = self.lookup_source_file_idx(sp.lo());
let hi = self.lookup_source_file_idx(sp.hi());
if lo != hi {
return true;
}
let f = (*self.files.borrow().source_files)[lo].clone();
f.lookup_line(sp.lo()) != f.lookup_line(sp.hi())
}
pub fn is_valid_span(&self, sp: Span) -> Result<(Loc, Loc), SpanLinesError> {