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Auto merge of #122013 - Swatinem:unicode-gen-fastpath, r=scottmcm

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Add a lower bound check to `unicode-table-generator` output

This adds a dedicated check for the lower bound
(if it is outside of ASCII range) to the output of the `unicode-table-generator` tool.

This generalized the ASCII-only fast-path, but only for the `Grapheme_Extend` property for now, as that is the only one with a lower bound outside of ASCII.
This commit is contained in:
bors 2024-04-20 20:33:25 +00:00
commit dbce3b43b6
4 changed files with 32 additions and 4 deletions
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2
library/core/src/char/methods.rs
View File

@ -927,7 +927,7 @@ pub fn is_control(self) -> bool {
#[must_use]
#[inline]
pub(crate) fn is_grapheme_extended(self) -> bool {
self > '\x7f' && unicode::Grapheme_Extend(self)
unicode::Grapheme_Extend(self)
}
/// Returns `true` if this `char` has one of the general categories for numbers.

4
library/core/src/unicode/unicode_data.rs
View File

@ -315,7 +315,11 @@ pub mod grapheme_extend {
15, 0, 7, 1, 17, 2, 7, 1, 2, 1, 5, 100, 1, 160, 7, 0, 1, 61, 4, 0, 4, 0, 7, 109, 7, 0, 96,
128, 240, 0,
];
#[inline]
pub fn lookup(c: char) -> bool {
(c as u32) >= 0x300 && lookup_slow(c)
}
fn lookup_slow(c: char) -> bool {
super::skip_search(
c as u32,
&SHORT_OFFSET_RUNS,

6
src/tools/unicode-table-generator/src/raw_emitter.rs
View File

@ -23,6 +23,7 @@ fn blank_line(&mut self) {
}
fn emit_bitset(&mut self, ranges: &[Range<u32>]) -> Result<(), String> {
let first_code_point = ranges.first().unwrap().start;
let last_code_point = ranges.last().unwrap().end;
// bitset for every bit in the codepoint range
//
@ -101,7 +102,10 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
)
.unwrap();
writeln!(&mut self.file, "pub const fn lookup(c: char) -> bool {{").unwrap();
writeln!(&mut self.file, " super::bitset_search(",).unwrap();
if first_code_point > 0x7f {
writeln!(&mut self.file, " (c as u32) >= {first_code_point:#04x} &&").unwrap();
}
writeln!(&mut self.file, " super::bitset_search(").unwrap();
writeln!(&mut self.file, " c as u32,").unwrap();
writeln!(&mut self.file, " &BITSET_CHUNKS_MAP,").unwrap();
writeln!(&mut self.file, " &BITSET_INDEX_CHUNKS,").unwrap();

24
src/tools/unicode-table-generator/src/skiplist.rs
View File

@ -25,8 +25,9 @@ fn pack(&self) -> u32 {
impl RawEmitter {
pub fn emit_skiplist(&mut self, ranges: &[Range<u32>]) {
let first_code_point = ranges.first().unwrap().start;
let mut offsets = Vec::<u32>::new();
let points = ranges.iter().flat_map(|r| vec![r.start, r.end]).collect::<Vec<u32>>();
let points = ranges.iter().flat_map(|r| [r.start, r.end]).collect::<Vec<u32>>();
let mut offset = 0;
for pt in points {
let delta = pt - offset;
@ -86,7 +87,26 @@ pub fn emit_skiplist(&mut self, ranges: &[Range<u32>]) {
.unwrap();
self.bytes_used += coded_offsets.len();
writeln!(&mut self.file, "pub fn lookup(c: char) -> bool {{").unwrap();
// The inlining in this code works like the following:
//
// The `skip_search` function is always inlined into the parent `lookup` fn,
// thus the compiler can generate optimal code based on the referenced `static`s.
//
// In the case of ASCII optimization, the lower-bounds check is inlined into
// the caller, and slower-path `skip_search` is outlined into a separate `lookup_slow` fn.
//
// Thus, in both cases, the `skip_search` function is specialized for the `static`s,
// and outlined into the prebuilt `std`.
if first_code_point > 0x7f {
writeln!(&mut self.file, "#[inline]").unwrap();
writeln!(&mut self.file, "pub fn lookup(c: char) -> bool {{").unwrap();
writeln!(&mut self.file, " (c as u32) >= {first_code_point:#04x} && lookup_slow(c)")
.unwrap();
writeln!(&mut self.file, "}}").unwrap();
writeln!(&mut self.file, "fn lookup_slow(c: char) -> bool {{").unwrap();
} else {
writeln!(&mut self.file, "pub fn lookup(c: char) -> bool {{").unwrap();
}
writeln!(&mut self.file, " super::skip_search(",).unwrap();
writeln!(&mut self.file, " c as u32,").unwrap();
writeln!(&mut self.file, " &SHORT_OFFSET_RUNS,").unwrap();