bjoernager/rust
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Optimize .debug_line generation

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This reduces the amount of time spent in .debug_line generation by about 50%

Fixes #807
This commit is contained in:
bjorn3 2020-01-14 16:11:23 +01:00
parent 4fbb45c3f3
commit 29fafb44b1
1 changed files with 15 additions and 9 deletions
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24
src/debuginfo/line_info.rs
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@ -122,19 +122,25 @@ impl<'a, 'tcx> FunctionDebugContext<'a, 'tcx> {
ebbs.sort_by_key(|ebb| func.offsets[*ebb]); // Ensure inst offsets always increase
let line_strings = &mut self.debug_context.dwarf.line_strings;
let mut last_file = None;
let mut create_row_for_span = |line_program: &mut LineProgram, span: Span| {
let loc = tcx.sess.source_map().lookup_char_pos(span.lo());
let file_id = line_program_add_file(line_program, line_strings, &loc.file.name);
/*println!(
"srcloc {:>04X} {}:{}:{}",
line_program.row().address_offset,
file.display(),
loc.line,
loc.col.to_u32()
);*/
// line_program_add_file is very slow.
// Optimize for the common case of the current file not being changed.
let current_file_changed = if let Some(last_file) = &mut last_file {
// If the allocations are not equal, then the files may still be equal, but that
// is not a problem, as this is just an optimization.
!Lrc::ptr_eq(last_file, &loc.file)
} else {
true
};
if current_file_changed {
let file_id = line_program_add_file(line_program, line_strings, &loc.file.name);
line_program.row().file = file_id;
last_file = Some(loc.file.clone());
}
line_program.row().file = file_id;
line_program.row().line = loc.line as u64;
line_program.row().column = loc.col.to_u32() as u64 + 1;
line_program.generate_row();