bjoernager/rust
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Remove support for decompressing dylib metadata

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We haven't been compressing dylib metadata for a while now. Removing
decompression support will regress error messages about an incompatible
rustc version being used, but dylibs are pretty rare anyway.
This commit is contained in:
bjorn3 2024-03-22 20:11:32 +00:00
parent 4d296eabe4
commit 87b9c092fb
4 changed files with 4 additions and 35 deletions
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1
compiler/rustc_metadata/Cargo.toml
View file

@ -27,7 +27,6 @@ rustc_session = { path = "../rustc_session" }
rustc_span = { path = "../rustc_span" }
rustc_target = { path = "../rustc_target" }
rustc_type_ir = { path = "../rustc_type_ir" }
snap = "1"
tempfile = "3.2"
tracing = "0.1"
# tidy-alphabetical-end

29
compiler/rustc_metadata/src/locator.rs
View file

@ -213,7 +213,7 @@
//! metadata::locator or metadata::creader for all the juicy details!
use std::borrow::Cow;
use std::io::{Read, Result as IoResult, Write};
use std::io::{Result as IoResult, Write};
use std::ops::Deref;
use std::path::{Path, PathBuf};
use std::{cmp, fmt};
@ -232,7 +232,6 @@ use rustc_session::utils::CanonicalizedPath;
use rustc_span::Span;
use rustc_span::symbol::Symbol;
use rustc_target::spec::{Target, TargetTriple};
use snap::read::FrameDecoder;
use tracing::{debug, info};
use crate::creader::{Library, MetadataLoader};
@ -792,7 +791,6 @@ fn get_metadata_section<'p>(
CrateFlavor::Dylib => {
let buf =
loader.get_dylib_metadata(target, filename).map_err(MetadataError::LoadFailure)?;
// The header is uncompressed
let header_len = METADATA_HEADER.len();
// header + u64 length of data
let data_start = header_len + 8;
@ -806,7 +804,7 @@ fn get_metadata_section<'p>(
)));
}
// Length of the compressed stream - this allows linkers to pad the section if they want
// Length of the metadata - this allows linkers to pad the section if they want
let Ok(len_bytes) =
<[u8; 8]>::try_from(&buf[header_len..cmp::min(data_start, buf.len())])
else {
@ -814,29 +812,10 @@ fn get_metadata_section<'p>(
"invalid metadata length found".to_string(),
));
};
let compressed_len = u64::from_le_bytes(len_bytes) as usize;
let metadata_len = u64::from_le_bytes(len_bytes) as usize;
// Header is okay -> inflate the actual metadata
let compressed_bytes = buf.slice(|buf| &buf[data_start..(data_start + compressed_len)]);
if &compressed_bytes[..cmp::min(METADATA_HEADER.len(), compressed_bytes.len())]
== METADATA_HEADER
{
// The metadata was not actually compressed.
compressed_bytes
} else {
debug!("inflating {} bytes of compressed metadata", compressed_bytes.len());
// Assume the decompressed data will be at least the size of the compressed data, so we
// don't have to grow the buffer as much.
let mut inflated = Vec::with_capacity(compressed_bytes.len());
FrameDecoder::new(&*compressed_bytes).read_to_end(&mut inflated).map_err(|_| {
MetadataError::LoadFailure(format!(
"failed to decompress metadata: {}",
filename.display()
))
})?;
slice_owned(inflated, Deref::deref)
}
buf.slice(|buf| &buf[data_start..(data_start + metadata_len)])
}
CrateFlavor::Rmeta => {
// mmap the file, because only a small fraction of it is read.