bjoernager/rust
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Only encode position from start of file.

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This commit is contained in:
Camille GILLOT 2022-08-07 12:27:38 +02:00
parent 16ba778c12
commit bacb4db48c
4 changed files with 22 additions and 30 deletions
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18
compiler/rustc_metadata/src/rmeta/decoder.rs
View file

@ -581,28 +581,26 @@ impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for Span {
foreign_data.imported_source_file(metadata_index, sess)
};
// Make sure our binary search above is correct.
// Make sure our span is well-formed.
debug_assert!(
lo >= source_file.original_start_pos && lo <= source_file.original_end_pos,
"Bad binary search: lo={:?} source_file.original_start_pos={:?} source_file.original_end_pos={:?}",
lo + source_file.original_start_pos <= source_file.original_end_pos,
"Malformed encoded span: lo={:?} source_file.original_start_pos={:?} source_file.original_end_pos={:?}",
lo,
source_file.original_start_pos,
source_file.original_end_pos
);
// Make sure we correctly filtered out invalid spans during encoding
// Make sure we correctly filtered out invalid spans during encoding.
debug_assert!(
hi >= source_file.original_start_pos && hi <= source_file.original_end_pos,
"Bad binary search: hi={:?} source_file.original_start_pos={:?} source_file.original_end_pos={:?}",
hi + source_file.original_start_pos <= source_file.original_end_pos,
"Malformed encoded span: hi={:?} source_file.original_start_pos={:?} source_file.original_end_pos={:?}",
hi,
source_file.original_start_pos,
source_file.original_end_pos
);
let lo =
(lo + source_file.translated_source_file.start_pos) - source_file.original_start_pos;
let hi =
(hi + source_file.translated_source_file.start_pos) - source_file.original_start_pos;
let lo = lo + source_file.translated_source_file.start_pos;
let hi = hi + source_file.translated_source_file.start_pos;
// Do not try to decode parent for foreign spans.
Span::new(lo, hi, ctxt, None)

26
compiler/rustc_metadata/src/rmeta/encoder.rs
View file

@ -235,6 +235,7 @@ impl<'a, 'tcx> Encodable<EncodeContext<'a, 'tcx>> for Span {
(source_map.files()[source_file_index].clone(), source_file_index);
}
let (ref source_file, source_file_index) = s.source_file_cache;
debug_assert!(source_file.contains(span.lo));
if !source_file.contains(span.hi) {
// Unfortunately, macro expansion still sometimes generates Spans
@ -242,9 +243,6 @@ impl<'a, 'tcx> Encodable<EncodeContext<'a, 'tcx>> for Span {
return TAG_PARTIAL_SPAN.encode(s);
}
// Length is independent of the span provenance.
let len = span.hi - span.lo;
// There are two possible cases here:
// 1. This span comes from a 'foreign' crate - e.g. some crate upstream of the
// crate we are writing metadata for. When the metadata for *this* crate gets
@ -261,7 +259,7 @@ impl<'a, 'tcx> Encodable<EncodeContext<'a, 'tcx>> for Span {
// if we're a proc-macro crate.
// This allows us to avoid loading the dependencies of proc-macro crates: all of
// the information we need to decode `Span`s is stored in the proc-macro crate.
let (tag, lo, metadata_index) = if source_file.is_imported() && !s.is_proc_macro {
let (tag, metadata_index) = if source_file.is_imported() && !s.is_proc_macro {
// To simplify deserialization, we 'rebase' this span onto the crate it originally came from
// (the crate that 'owns' the file it references. These rebased 'lo' and 'hi' values
// are relative to the source map information for the 'foreign' crate whose CrateNum
@ -271,18 +269,15 @@ impl<'a, 'tcx> Encodable<EncodeContext<'a, 'tcx>> for Span {
//
// All of this logic ensures that the final result of deserialization is a 'normal'
// Span that can be used without any additional trouble.
let (external_start_pos, metadata_index) = {
let metadata_index = {
// Introduce a new scope so that we drop the 'lock()' temporary
match &*source_file.external_src.lock() {
ExternalSource::Foreign { original_start_pos, metadata_index, .. } => {
(*original_start_pos, *metadata_index)
}
ExternalSource::Foreign { metadata_index, .. } => *metadata_index,
src => panic!("Unexpected external source {:?}", src),
}
};
let lo = (span.lo - source_file.start_pos) + external_start_pos;
(TAG_VALID_SPAN_FOREIGN, lo, metadata_index)
(TAG_VALID_SPAN_FOREIGN, metadata_index)
} else {
// Record the fact that we need to encode the data for this `SourceFile`
let source_files =
@ -291,14 +286,19 @@ impl<'a, 'tcx> Encodable<EncodeContext<'a, 'tcx>> for Span {
let metadata_index: u32 =
metadata_index.try_into().expect("cannot export more than U32_MAX files");
(TAG_VALID_SPAN_LOCAL, span.lo, metadata_index)
(TAG_VALID_SPAN_LOCAL, metadata_index)
};
tag.encode(s);
lo.encode(s);
// Encode the start position relative to the file start, so we profit more from the
// variable-length integer encoding.
let lo = span.lo - source_file.start_pos;
// Encode length which is usually less than span.hi and profits more
// from the variable-length integer encoding that we use.
let len = span.hi - span.lo;
tag.encode(s);
lo.encode(s);
len.encode(s);
// Encode the index of the `SourceFile` for the span, in order to make decoding faster.

4
compiler/rustc_span/src/lib.rs
View file

@ -1094,10 +1094,6 @@ pub enum ExternalSource {
Unneeded,
Foreign {
kind: ExternalSourceKind,
/// This SourceFile's byte-offset within the source_map of its original crate.
original_start_pos: BytePos,
/// The end of this SourceFile within the source_map of its original crate.
original_end_pos: BytePos,
/// Index of the file inside metadata.
metadata_index: u32,
},

4
compiler/rustc_span/src/source_map.rs
View file

@ -336,7 +336,7 @@ impl SourceMap {
mut file_local_non_narrow_chars: Vec<NonNarrowChar>,
mut file_local_normalized_pos: Vec<NormalizedPos>,
original_start_pos: BytePos,
original_end_pos: BytePos,
_original_end_pos: BytePos,
metadata_index: u32,
) -> Lrc<SourceFile> {
let start_pos = self
@ -382,8 +382,6 @@ impl SourceMap {
src_hash,
external_src: Lock::new(ExternalSource::Foreign {
kind: ExternalSourceKind::AbsentOk,
original_start_pos,
original_end_pos,
metadata_index,
}),
start_pos,