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Unrolled build for rust-lang#113142
Rollup merge of rust-lang#113142 - the8472:opt-cstr-display, r=Mark-Simulacrum optimize EscapeAscii's Display and CStr's Debug ``` old: ascii::bench_ascii_escape_display_mixed 17.97µs/iter +/- 204.00ns ascii::bench_ascii_escape_display_no_escape 545.00ns/iter +/- 6.00ns new: ascii::bench_ascii_escape_display_mixed 4.99µs/iter +/- 56.00ns ascii::bench_ascii_escape_display_no_escape 91.00ns/iter +/- 1.00ns ```
2 parents 5378c1c + 6c87448 commit dc17111

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‎library/core/benches/ascii.rs

+28
Original file line numberDiff line numberDiff line change
@@ -63,6 +63,7 @@ macro_rules! benches {
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}
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}
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66+
use std::fmt::Write;
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use test::black_box;
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use test::Bencher;
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@@ -351,3 +352,30 @@ static ASCII_CHARACTER_CLASS: [AsciiCharacterClass; 256] = [
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N, N, N, N, N, N, N, N, N, N, N, N, N, N, N, N,
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N, N, N, N, N, N, N, N, N, N, N, N, N, N, N, N,
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];
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const ASCII_PATH: &[u8] = b"home/kyubey/rust/build/x86_64-unknown-linux-gnu/stage0/lib:/home/kyubey/workspace/rust/build/x86_64-unknown-linux-gnu/stage0-tools/release/deps";
357+
const RUST_INCANTATION: &[u8] = br#"AR_x86_64_unknown_linux_gnu="ar" CARGO_INCREMENTAL="0" CARGO_PROFILE_RELEASE_DEBUG="1" CARGO_PROFILE_RELEASE_DEBUG_ASSERTIONS="false" CARGO_PROFILE_RELEASE_OVERFLOW_CHECKS="false" CARGO_TARGET_DIR="/home/kyubey/workspace/rust/build/x86_64-unknown-linux-gnu/stage0-std" CC_x86_64_unknown_linux_gnu="cc" CFG_COMPILER_HOST_TRIPLE="x86_64-unknown-linux-gnu" CFG_RELEASE_CHANNEL="dev" CFLAGS_x86_64_unknown_linux_gnu="-ffunction-sections -fdata-sections -fPIC -m64" CXXFLAGS_x86_64_unknown_linux_gnu="-ffunction-sections -fdata-sections -fPIC -m64" CXX_x86_64_unknown_linux_gnu="c++" LD_LIBRARY_PATH="/home/kyubey/workspace/rust/build/x86_64-unknown-linux-gnu/stage0-sysroot/lib/rustlib/x86_64-unknown-linux-gnu/lib" LIBC_CHECK_CFG="1" RANLIB_x86_64_unknown_linux_gnu="ar s" REAL_LIBRARY_PATH_VAR="LD_LIBRARY_PATH" RUSTBUILD_NATIVE_DIR="/home/kyubey/workspace/rust/build/x86_64-unknown-linux-gnu/native" RUSTC="/home/kyubey/workspace/rust/build/bootstrap/debug/rustc" RUSTC_BOOTSTRAP="1" RUSTC_BREAK_ON_ICE="1" RUSTC_ERROR_METADATA_DST="/home/kyubey/workspace/rust/build/tmp/extended-error-metadata" RUSTC_FORCE_UNSTABLE="1" RUSTC_HOST_FUSE_LD_LLD="1" RUSTC_INSTALL_BINDIR="bin" RUSTC_LIBDIR="/home/kyubey/workspace/rust/build/x86_64-unknown-linux-gnu/stage0/lib" RUSTC_LINT_FLAGS="-Wrust_2018_idioms -Wunused_lifetimes -Wsemicolon_in_expressions_from_macros" RUSTC_REAL="/home/kyubey/workspace/rust/build/x86_64-unknown-linux-gnu/stage0/bin/rustc" RUSTC_SNAPSHOT="/home/kyubey/workspace/rust/build/x86_64-unknown-linux-gnu/stage0/bin/rustc" RUSTC_SNAPSHOT_LIBDIR="/home/kyubey/workspace/rust/build/x86_64-unknown-linux-gnu/stage0/lib" RUSTC_STAGE="0" RUSTC_SYSROOT="/home/kyubey/workspace/rust/build/x86_64-unknown-linux-gnu/stage0-sysroot" RUSTC_VERBOSE="0" RUSTDOC="/home/kyubey/workspace/rust/build/bootstrap/debug/rustdoc" RUSTDOCFLAGS="-C target-cpu=native --cfg=bootstrap -Csymbol-mangling-version=legacy -Zunstable-options -Zunstable-options --check-cfg=values(bootstrap) --check-cfg=values(stdarch_intel_sde) --check-cfg=values(no_fp_fmt_parse) --check-cfg=values(no_global_oom_handling) --check-cfg=values(no_rc) --check-cfg=values(no_sync) --check-cfg=values(freebsd12) --check-cfg=values(freebsd13) --check-cfg=values(backtrace_in_libstd) --check-cfg=values(target_env,\"libnx\") --check-cfg=values(target_arch,\"asmjs\",\"spirv\",\"nvptx\",\"xtensa\") -Clink-arg=-fuse-ld=lld -Clink-arg=-Wl,--threads=1 -Wrustdoc::invalid_codeblock_attributes --crate-version 1.72.0-dev -Zcrate-attr=doc(html_root_url=\"https://doc.rust-lang.org/nightly/\") -Zcrate-attr=warn(rust_2018_idioms)" RUSTDOC_FUSE_LD_LLD="1" RUSTDOC_LIBDIR="/home/kyubey/workspace/rust/build/x86_64-unknown-linux-gnu/stage0/lib" RUSTDOC_REAL="/path/to/nowhere/rustdoc/not/required" RUSTFLAGS="-C target-cpu=native --cfg=bootstrap -Csymbol-mangling-version=legacy -Zunstable-options -Zunstable-options --check-cfg=values(bootstrap) --check-cfg=values(stdarch_intel_sde) --check-cfg=values(no_fp_fmt_parse) --check-cfg=values(no_global_oom_handling) --check-cfg=values(no_rc) --check-cfg=values(no_sync) --check-cfg=values(freebsd12) --check-cfg=values(freebsd13) --check-cfg=values(backtrace_in_libstd) --check-cfg=values(target_env,\"libnx\") --check-cfg=values(target_arch,\"asmjs\",\"spirv\",\"nvptx\",\"xtensa\") -Zmacro-backtrace -Clink-args=-Wl,-z,origin -Clink-args=-Wl,-rpath,$ORIGIN/../lib -Clink-args=-fuse-ld=lld -Csplit-debuginfo=off -Cprefer-dynamic -Zinline-mir -Clto=off -Zcrate-attr=doc(html_root_url=\"https://doc.rust-lang.org/nightly/\")" RUST_COMPILER_RT_ROOT="/home/kyubey/workspace/rust/src/llvm-project/compiler-rt" RUST_TEST_THREADS="48" WINAPI_NO_BUNDLED_LIBRARIES="1" __CARGO_DEFAULT_LIB_METADATA="bootstrapstd" "/home/kyubey/workspace/rust/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "bench" "--target" "x86_64-unknown-linux-gnu" "-Zcheck-cfg=names,values,output" "-Zbinary-dep-depinfo" "-j" "48" "--features" " panic-unwind backtrace compiler-builtins-c" "--manifest-path" "/home/kyubey/workspace/rust/library/sysroot/Cargo.toml" "-p" "core" "--" "bench_ascii_escape_display" "--quiet" "-Z" "unstable-options" "--format" "json""#;
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#[bench]
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fn bench_ascii_escape_display_no_escape(b: &mut Bencher) {
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let mut writer = String::with_capacity(8 * 1024);
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b.iter(move || {
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writer.clear();
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let iter = ASCII_PATH.escape_ascii();
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write!(writer, "{}", iter).unwrap();
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writer.len()
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})
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}
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#[bench]
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fn bench_ascii_escape_display_mixed(b: &mut Bencher) {
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let mut writer = String::with_capacity(8 * 1024);
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b.iter(move || {
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writer.clear();
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let iter = RUST_INCANTATION.escape_ascii();
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write!(writer, "{}", iter).unwrap();
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writer.len()
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})
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}

‎library/core/src/ascii.rs

+11
Original file line numberDiff line numberDiff line change
@@ -96,6 +96,17 @@ pub fn escape_default(c: u8) -> EscapeDefault {
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EscapeDefault(escape::EscapeIterInner::new(data, range))
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}
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99+
impl EscapeDefault {
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pub(crate) fn empty() -> Self {
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let data = [Char::Null; 4];
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EscapeDefault(escape::EscapeIterInner::new(data, 0..0))
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}
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pub(crate) fn as_str(&self) -> &str {
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self.0.as_str()
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}
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}
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#[stable(feature = "rust1", since = "1.0.0")]
100111
impl Iterator for EscapeDefault {
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type Item = u8;

‎library/core/src/iter/adapters/flatten.rs

+8
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@@ -24,6 +24,14 @@ impl<I: Iterator, U: IntoIterator, F: FnMut(I::Item) -> U> FlatMap<I, U, F> {
2424
pub(in crate::iter) fn new(iter: I, f: F) -> FlatMap<I, U, F> {
2525
FlatMap { inner: FlattenCompat::new(iter.map(f)) }
2626
}
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pub(crate) fn into_parts(self) -> (Option<U::IntoIter>, Option<I>, Option<U::IntoIter>) {
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(
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self.inner.frontiter,
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self.inner.iter.into_inner().map(Map::into_inner),
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self.inner.backiter,
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)
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}
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}
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2937
#[stable(feature = "rust1", since = "1.0.0")]

‎library/core/src/iter/adapters/fuse.rs

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@@ -24,6 +24,10 @@ impl<I> Fuse<I> {
2424
pub(in crate::iter) fn new(iter: I) -> Fuse<I> {
2525
Fuse { iter: Some(iter) }
2626
}
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pub(crate) fn into_inner(self) -> Option<I> {
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self.iter
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}
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}
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2933
#[stable(feature = "fused", since = "1.26.0")]

‎library/core/src/iter/adapters/map.rs

+4
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@@ -69,6 +69,10 @@ impl<I, F> Map<I, F> {
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pub(in crate::iter) fn new(iter: I, f: F) -> Map<I, F> {
7070
Map { iter, f }
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}
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pub(crate) fn into_inner(self) -> I {
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self.iter
75+
}
7276
}
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7478
#[stable(feature = "core_impl_debug", since = "1.9.0")]

‎library/core/src/slice/ascii.rs

+40-1
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@@ -5,6 +5,7 @@ use crate::fmt::{self, Write};
55
use crate::iter;
66
use crate::mem;
77
use crate::ops;
8+
use core::ascii::EscapeDefault;
89

910
#[cfg(not(test))]
1011
impl [u8] {
@@ -253,7 +254,45 @@ impl<'a> iter::FusedIterator for EscapeAscii<'a> {}
253254
#[stable(feature = "inherent_ascii_escape", since = "1.60.0")]
254255
impl<'a> fmt::Display for EscapeAscii<'a> {
255256
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
256-
self.clone().try_for_each(|b| f.write_char(b as char))
257+
// disassemble iterator, including front/back parts of flatmap in case it has been partially consumed
258+
let (front, slice, back) = self.clone().inner.into_parts();
259+
let front = front.unwrap_or(EscapeDefault::empty());
260+
let mut bytes = slice.unwrap_or_default().as_slice();
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let back = back.unwrap_or(EscapeDefault::empty());
262+
263+
// usually empty, so the formatter won't have to do any work
264+
for byte in front {
265+
f.write_char(byte as char)?;
266+
}
267+
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fn needs_escape(b: u8) -> bool {
269+
b > 0x7E || b < 0x20 || b == b'\\' || b == b'\'' || b == b'"'
270+
}
271+
272+
while bytes.len() > 0 {
273+
// fast path for the printable, non-escaped subset of ascii
274+
let prefix = bytes.iter().take_while(|&&b| !needs_escape(b)).count();
275+
// SAFETY: prefix length was derived by counting bytes in the same splice, so it's in-bounds
276+
let (prefix, remainder) = unsafe { bytes.split_at_unchecked(prefix) };
277+
// SAFETY: prefix is a valid utf8 sequence, as it's a subset of ASCII
278+
let prefix = unsafe { crate::str::from_utf8_unchecked(prefix) };
279+
280+
f.write_str(prefix)?; // the fast part
281+
282+
bytes = remainder;
283+
284+
if let Some(&b) = bytes.first() {
285+
// guaranteed to be non-empty, better to write it as a str
286+
f.write_str(ascii::escape_default(b).as_str())?;
287+
bytes = &bytes[1..];
288+
}
289+
}
290+
291+
// also usually empty
292+
for byte in back {
293+
f.write_char(byte as char)?;
294+
}
295+
Ok(())
257296
}
258297
}
259298
#[stable(feature = "inherent_ascii_escape", since = "1.60.0")]

‎library/core/tests/ascii.rs

+10
Original file line numberDiff line numberDiff line change
@@ -479,3 +479,13 @@ fn ascii_ctype_const() {
479479
is_ascii_control => [false, false, false, false, false];
480480
}
481481
}
482+
483+
#[test]
484+
fn test_ascii_display() {
485+
assert_eq!(b"foo'bar".escape_ascii().to_string(), r#"foo\'bar"#);
486+
assert_eq!(b"\0\xff".escape_ascii().to_string(), r#"\x00\xff"#);
487+
let mut it = b"\0fastpath\xffremainder\xff".escape_ascii();
488+
let _ = it.advance_by(4);
489+
let _ = it.advance_back_by(4);
490+
assert_eq!(it.to_string(), r#"fastpath\xffremainder"#);
491+
}

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