perf(lexer): use bitshifting when parsing known integers

[DonIsaac]

What This PR Does

• perf(lexer): use bit shifting when parsing hex, octal, and binary integers instead of mul_add-ing on f64s. Check out the difference in assembly generated here
• perf(lexer): skip redundant utf8 check when parsing BigInts
• refactor(lexer): remove unsafe usage (as per @overlookmotel's request here)
• test(lexer): add numeric parsing unit tests

I don't expect this PR to have a large performance improvement, since the most common case (Kind::Decimal) is not affected. We could do this, however, by splitting Kind::Decimal into Kind::DecimalFloat and Kind::DecimalInt when the lexer encounters a .

[graphite-app]

Your org has enabled the Graphite merge queue for merging into main

Add the label “merge” to the PR and Graphite will automatically add it to the merge queue when it’s ready to merge. Or use the label “hotfix” to add to the merge queue as a hot fix.

You must have a Graphite account and log in to Graphite in order to use the merge queue. Sign up using this link.

[codspeed-hq]

CodSpeed Performance Report

Merging #3296 will not alter performance

_{Comparing don/perf/lexer/shift-when-parsing-ints (61757a1) with main (712ee0d)}

Summary

✅ 27 untouched benchmarks

[Boshen]

use bit shifting

Can you comment why it's better on the spot for future contributors.

[overlookmotel]

Just to say, the bitshift algorithm is brilliant! Very smart.

Interesting that compiler unrolls the loop. Looks like it unrolls in batches of 4 characters, which should be good for this use case. If it had used batches of 8 chars for octals, that'd likely be a de-opt because JS rarely contains numbers which are as large as 8 digits (decimal or octal).

[DonIsaac]

use bit shifting

Can you comment why it's better on the spot for future contributors.

In this PR discussion, or in the code?

[overlookmotel]

use bit shifting

Can you comment why it's better on the spot for future contributors.

In this PR discussion, or in the code?

I think by "on the spot", Boshen means in the code in the place where it happens.

[Boshen]

Yes, in the code.

[Boshen]

Brilliant work! Thank you!