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rustc_span: Remove transmutes from span encoding

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This commit is contained in:
Vadim Petrochenkov 2024-06-13 19:50:44 +03:00
parent 6fea953267
commit 220f3ec99f
1 changed files with 37 additions and 15 deletions
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52
compiler/rustc_span/src/span_encoding.rs
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@ -4,10 +4,10 @@ use crate::SPAN_TRACK;
use crate::{BytePos, SpanData};
use rustc_data_structures::fx::FxIndexSet;
// This code is very hot and uses lots of arithmetic, avoid overflow checks for performance.
// See https://github.com/rust-lang/rust/pull/119440#issuecomment-1874255727
use rustc_serialize::int_overflow::DebugStrictAdd;
use std::mem::transmute;
/// A compressed span.
///
@ -105,15 +105,12 @@ struct InlineParent {
#[derive(Clone, Copy)]
struct PartiallyInterned {
index: u32,
_marker1: u16,
ctxt: u16,
}
#[derive(Clone, Copy)]
struct Interned {
index: u32,
_marker1: u16,
_marker2: u16,
}
impl InlineCtxt {
@ -130,7 +127,13 @@ impl InlineCtxt {
}
#[inline]
fn span(lo: u32, len: u16, ctxt: u16) -> Span {
unsafe { transmute(InlineCtxt { lo, len, ctxt }) }
Span { lo_or_index: lo, len_with_tag_or_marker: len, ctxt_or_parent_or_marker: ctxt }
}
#[inline]
fn from_span(span: Span) -> InlineCtxt {
let (lo, len, ctxt) =
(span.lo_or_index, span.len_with_tag_or_marker, span.ctxt_or_parent_or_marker);
InlineCtxt { lo, len, ctxt }
}
}
@ -147,8 +150,16 @@ impl InlineParent {
}
}
#[inline]
fn span(lo: u32, len_with_tag: u16, parent: u16) -> Span {
unsafe { transmute(InlineParent { lo, len_with_tag, parent }) }
fn span(lo: u32, len: u16, parent: u16) -> Span {
let (lo_or_index, len_with_tag_or_marker, ctxt_or_parent_or_marker) =
(lo, PARENT_TAG | len, parent);
Span { lo_or_index, len_with_tag_or_marker, ctxt_or_parent_or_marker }
}
#[inline]
fn from_span(span: Span) -> InlineParent {
let (lo, len_with_tag, parent) =
(span.lo_or_index, span.len_with_tag_or_marker, span.ctxt_or_parent_or_marker);
InlineParent { lo, len_with_tag, parent }
}
}
@ -162,7 +173,13 @@ impl PartiallyInterned {
}
#[inline]
fn span(index: u32, ctxt: u16) -> Span {
unsafe { transmute(PartiallyInterned { index, _marker1: BASE_LEN_INTERNED_MARKER, ctxt }) }
let (lo_or_index, len_with_tag_or_marker, ctxt_or_parent_or_marker) =
(index, BASE_LEN_INTERNED_MARKER, ctxt);
Span { lo_or_index, len_with_tag_or_marker, ctxt_or_parent_or_marker }
}
#[inline]
fn from_span(span: Span) -> PartiallyInterned {
PartiallyInterned { index: span.lo_or_index, ctxt: span.ctxt_or_parent_or_marker }
}
}
@ -173,8 +190,13 @@ impl Interned {
}
#[inline]
fn span(index: u32) -> Span {
let _marker1 = BASE_LEN_INTERNED_MARKER;
unsafe { transmute(Interned { index, _marker1, _marker2: CTXT_INTERNED_MARKER }) }
let (lo_or_index, len_with_tag_or_marker, ctxt_or_parent_or_marker) =
(index, BASE_LEN_INTERNED_MARKER, CTXT_INTERNED_MARKER);
Span { lo_or_index, len_with_tag_or_marker, ctxt_or_parent_or_marker }
}
#[inline]
fn from_span(span: Span) -> Interned {
Interned { index: span.lo_or_index }
}
}
@ -192,20 +214,20 @@ macro_rules! match_span_kind {
if $span.len_with_tag_or_marker != BASE_LEN_INTERNED_MARKER {
if $span.len_with_tag_or_marker & PARENT_TAG == 0 {
// Inline-context format.
let $span1: InlineCtxt = unsafe { transmute($span) };
let $span1 = InlineCtxt::from_span($span);
$arm1
} else {
// Inline-parent format.
let $span2: InlineParent = unsafe { transmute($span) };
let $span2 = InlineParent::from_span($span);
$arm2
}
} else if $span.ctxt_or_parent_or_marker != CTXT_INTERNED_MARKER {
// Partially-interned format.
let $span3: PartiallyInterned = unsafe { transmute($span) };
let $span3 = PartiallyInterned::from_span($span);
$arm3
} else {
// Interned format.
let $span4: Interned = unsafe { transmute($span) };
let $span4 = Interned::from_span($span);
$arm4
}
};
@ -245,7 +267,7 @@ impl Span {
&& let parent32 = parent.local_def_index.as_u32()
&& parent32 <= MAX_CTXT
{
return InlineParent::span(lo.0, PARENT_TAG | len as u16, parent32 as u16);
return InlineParent::span(lo.0, len as u16, parent32 as u16);
}
}