Transformer performing extremely badly on cal.com benchmark

[overlookmotel]

#5324 enabled all > es6 transforms in our transformer benchmarks.

As expected, measured performance dropped a lot, because the transformer doing much more work in our benchmarks.

However, something is badly wrong with the transformer on the cal.com benchmark. It went from 12.2 ms to over 6 seconds!

I doubt this is a problem with the benchmarks. Likely one of the transforms is behaving extremely badly in some circumstances, and the cal.com fixture is triggering that behavior.

But which transform is the culprit?

[Boshen]

It's this:

                    // Enable React related plugins
                    transform_options.react.development = true;

What's so special about development?

[Boshen]

oxc/crates/oxc_transformer/src/react/jsx_source.rs

Lines 87 to 90 in 64db1b4

	// TODO: We shouldn't calculate line + column from scratch each time as it's expensive.
	// Build a table of byte indexes of each line's start on first usage, and save it.
	// Then calculate line and column from that.
	let (line, column) = get_line_column(elem.span.start, self.ctx.source_text);

[Boshen]

[Boshen]

Continue in #5500