Write indentation faster. Previously was writing indentation to buffer with a call to `memset`, which is relatively expensive. Where indentation `<= 16` (common case), write 16 tabs with a single 16-byte XMM write, which is faster.
This PR does not upgrade rustc. Only changes are applied.
We cannot upgrade to the lastet Rust version yet due to wasm-bindgen
breaking some generated types.
THere's also some elided lifetimes in `**/generated/**`, which requires
modification to ast tools.
Breaking change. `Codegen::into_source_text` consume `Codegen`, instead of taking the `CodeBuffer` and substituting an empty one.
Keeping the `Codegen` alive seems unintuitive, as its state is then out of sync. Consuming the `CodeBuffer` is also marginally cheaper.
# What This PR Does
Adds `CodeBuffer`, a simple wrapper over a `Vec<u8>` with a protective and reduced API for upholding UTF-8 validity guarantees. Closes#6147.
Note that this struct is actually quite small. Most of the added lines are doc comments.
I am unable to print all comments correctly. Comments have way too much semantic meaning in JavaScript.
This PR reduces the scope to only print jsdoc comments that are attached to statements and class elements, in order to get isolated declarations shipped.
Previously it included a newline in the value
```
"hashbang": {
"type": "Hashbang",
"start": 0,
"end": 16,
"value": "/usr/bin/node\n"
},
```
This change will also make the lexer emit a `\n` token, which will make comment position detection correct.
`Codegen::with_source_text` gives us enough information to use `Codegen::with_capacity`. This change makes the API cleaner as users have to provide less redundant information.
Revert #5192 and add a comment that it's not a perf gain.
This was really surprising to me, but the benchmarks do demonstrate it.
Please see the benchmarks commit-by-commit on this PR. Adding `#[inline]` to the function does give +1% gain, but it's no better than it was before #5192. So I think preferable to just revert to the simpler original.
I think likely explanation is that the compiler is already performing this optimization itself. And if it does it itself, then it understands the code better, and can then make better decisions about inlining.
https://godbolt.org/z/xzhWWeMoe seems to demonstrate this - there are 2 calls to `Item::gen` in the generated assembly, so it has split the loop into 2.
try to fix: https://github.com/rolldown/rolldown/issues/2013
1. Before we only considering the ast is untouched, but considering the
scenario.
```js
const a = /*__PURE__*/ test(),
// ^^^ ^^^^^^ is removed during transform
b = a();
```
Then according to the previous algorithm, `PURE` will attach to `b =
a()`
2. Now, we try to attach comments as much as possible unless the
comments are separated by comments, for the case above, `PURE` will not
be attached to `a()` since the content between `b = a()` and `/*
__PURE__*/` is not all whitespace.
3. we added back `MoveMap`, for the special case
```js
/*__NODE_SIDE_EFFECTS__*/ export const c = 100;
// ^^^^^^^^^^^^^^^^^^^^^ should be attached to first declarator,
// ^^^^^^ are not whitespace
```
